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XyZspineZyX
07-24-2003, 08:51 AM
Wow the P-51B!

Will it be 5mph faster then the D model?
Will it have more directional stability then the cutaway fuselage D?
Will it be more agile because of the two 4x .50 instead of the D's 6x?
will it have better alround vision with the brithish 'Malcom hood'buble canopy, then the standard D buble canopy?

This is why some Ace's prefered their 'old' B/C Mustang over the newer D!

Something simular happend in the luftwaffe where the Experten preferd their 109 F over the newer G model wich was heavier, less agile but had heavier weapons wich was welcomed by the comon pilots who did not like the Ferdinand's 'weak'armament.
The LW Ace's expert at shooting tought the Ferdinand was the best Bf 109


Ps less enthaushast on the depressing wheater forecast for the channel front i would rather have some sunny Medetereanian or north African climate! (whe live under the depressing wheater of the Netherlands, while my wife is from Greece)

regards,
Kees.

XyZspineZyX
07-24-2003, 08:51 AM
Wow the P-51B!

Will it be 5mph faster then the D model?
Will it have more directional stability then the cutaway fuselage D?
Will it be more agile because of the two 4x .50 instead of the D's 6x?
will it have better alround vision with the brithish 'Malcom hood'buble canopy, then the standard D buble canopy?

This is why some Ace's prefered their 'old' B/C Mustang over the newer D!

Something simular happend in the luftwaffe where the Experten preferd their 109 F over the newer G model wich was heavier, less agile but had heavier weapons wich was welcomed by the comon pilots who did not like the Ferdinand's 'weak'armament.
The LW Ace's expert at shooting tought the Ferdinand was the best Bf 109


Ps less enthaushast on the depressing wheater forecast for the channel front i would rather have some sunny Medetereanian or north African climate! (whe live under the depressing wheater of the Netherlands, while my wife is from Greece)

regards,
Kees.

XyZspineZyX
07-24-2003, 10:02 AM
Ferdinand?
I beleive "Friedrich" or "Franz" to have been more commonly used.
I love the "F" model, especially the F2. You can kill with the MG151/15. Takes practice is all.
Nice post /i/smilies/16x16_smiley-wink.gif


http://members.cox.net/miataman1/wurger.bmp

XyZspineZyX
07-24-2003, 10:20 AM
i know only 1 "ace" that prefered the friedrich ...there where others too, sure.

but must 109 pilots loved the extra horsepower and high alt performance of the 109G2..then the loved the g6 ...and so on.


wastel


..talked to veterans...

XyZspineZyX
07-24-2003, 10:45 AM
Flydutch wrote:
- Wow the P-51B!
- will it have better alround vision with the brithish
- 'Malcom hood'buble canopy, then the standard D buble
- canopy?
-
- regards,
- Kees.
-
-

I doubt it /i/smilies/16x16_smiley-sad.gif The Malcolm hood made it possible to lean and have a better view to check your 6, but leaning isnt implemented in FB so there goes that advantage. Oh well i suppose its still going to rock /i/smilies/16x16_smiley-happy.gif

XyZspineZyX
07-24-2003, 11:55 AM
I believe the Ferdinand was some 62 tons heavier than the 109G. /i/smilies/16x16_smiley-wink.gif



http://www.x-plane.org/users/isegrim/FB-desktopweb.jpg
'Only a dead Indianer is a good Indianer!'

Vezérünk a Bátorság, K*sérµnk a Szerencse!
(Courage leads, Luck escorts us! - Historical motto of the 101st Puma Fighter Regiment)

Flight tests and other aviation performance data: http://www.pbase.com/isegrim

XyZspineZyX
07-24-2003, 12:06 PM
who cares about 62 tons if the wing area is large enough./i/smilies/16x16_smiley-very-happy.gif

http://www.geocities.com/kimurakai/SIG/262_01011.jpg


"Kimura, tu as une tªte carrée comme un sale boche!"



Message Edited on 07/24/0312:14PM by KIMURA

XyZspineZyX
07-24-2003, 12:08 PM
KIMURA wrote:
- who cares about 62 ton the wing area is large
- enough. /i/smilies/16x16_smiley-very-happy.gif

Very true. Plus you pack a 88mm. You have to be cautious with .50s penetrating your armor, though. /i/smilies/16x16_smiley-very-happy.gif

http://www.x-plane.org/users/isegrim/FB-desktopweb.jpg
'Only a dead Indianer is a good Indianer!'

Vezérünk a Bátorság, K*sérµnk a Szerencse!
(Courage leads, Luck escorts us! - Historical motto of the 101st Puma Fighter Regiment)

Flight tests and other aviation performance data: http://www.pbase.com/isegrim

XyZspineZyX
07-24-2003, 04:08 PM
Will it be 5mph faster THAN the D model?
Will it have more directional stability THAN the cutaway fuselage D?
Will it be more agile because of the two 4x .50 instead of the D's 6x?
will it have better alround vision with the brithish 'Malcom hood'buble canopy, THAN the standard D buble canopy?

OK! I'll stop!

XyZspineZyX
07-25-2003, 04:46 PM
Ok you guys i should have said "Fritz" instead of the 'Ferdinand' (Why not make it the 'Elephant'model, instead of Emil! LOL)
Did you smarties now that Friederich means 'Piece Empire'?
and is the original name for Fred, Bet you knew that to!

Serious now, I am happy for sure to know there will be the B/C model Mustang, Don Gentiles, or Stanislavs Skalki's paintjobs will look awsome on it!

XyZspineZyX
07-25-2003, 04:59 PM
There are P-15's in FB where??? Where can I get a P-51?

XyZspineZyX
07-26-2003, 11:11 AM
Mokpa they are under development chek the dev updates!

Wastel would you give my greetings to that sole Friederich expert that you are aquinted with?
It could not be Werner Moelders since he died during the war!
I have read several times that the 'snipers' under the expert thought the F to be the higkight and the Gustaf to be the downfall of the series.

XyZspineZyX
07-26-2003, 04:56 PM
There's method to the madness: Emil, Friedrich, Gustav...

All words in the german phonetic alphabet at the time. Each country had it's own during WWII like Ack, Beer in the early war years for the UK, Able, Baker for the US, which all morphed into the international phonetic alphabet in the 50's (I believe), Alfa, Bravo, etc.

Cheers!

jocko-

417 RCAF

Message Edited on 07/26/0304:56PM by jocko417

XyZspineZyX
07-26-2003, 07:20 PM
Flydutch wrote:

- Will it have more directional stability then the
- cutaway fuselage D?

Another stability problem was due to the centerline tank on the D model, The larger tank, when full, affected it adversly, so much so that they would burn the fuel in the centerline tank (to a point) before buring the fule in the drop tanks!

- Will it be more agile because of the two 4x .50
- instead of the D's 6x?

And will it have the electric motor BOOTED ammo feeds that made the .50 ROF goto 950 vs the NON-BOOSTED 750, thus increasing your chance of a hit n kill!

- This is why some Ace's prefered their 'old' B/C
- Mustang over the newer D!



TAGERT
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If WAR was not the ANSWER.. Than what the H was your QUESTION?

ZG77_Nagual
07-26-2003, 07:27 PM
The B is the better dogfighter by all accounts.

http://pws.chartermi.net/~cmorey/pics/p47janes.jpg

XyZspineZyX
07-26-2003, 09:41 PM
ZG77_Nagual wrote:
- The B is the better dogfighter by all accounts.
-
-
---------------------------------------------

S!,
I've read the same. The B model outperformed the D w/ the exception to outward visability. However, I've also read that the B model suffered from MGs jamming during hi-G turns. Was this ever corrected in the B model?

HB



American by birth; Southern by the Grace of God!

www.jagdverband44.com (http://www.jagdverband44.com)
http://www.jagdverband44.com/JV44Banner400x75.jpg

XyZspineZyX
07-26-2003, 10:18 PM
HeinzBar wrote:
- I've also read that the B model suffered from MGs
- jamming during hi-G turns. Was this ever corrected
- in the B model?

If I recall correctly, that was ONE of the reasons they did the BOOST with the el motors to pull/feed the ammo over that hump... the .50s were mounted in kind of cockeyed.. or it was a hump (wing strut) near the feed that caused the belt of ammo to get hung up... It has been awhile, but I belive that was the jist of it. Basically the BOOST was a byproduct of the jam fix.




TAGERT
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If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-26-2003, 10:44 PM
tagert wrote:
- If I recall correctly, that was ONE of the reasons
- they did the BOOST with the el motors to pull/feed
- the ammo over that hump... the .50s were mounted in
- kind of cockeyed.. or it was a hump (wing strut)
- near the feed that caused the belt of ammo to get
- hung up... It has been awhile, but I belive that was
- the jist of it. Basically the BOOST was a byproduct
- of the jam fix.

But why use the sledgehammer of the .50 when the
ball pean of the French Mac 1935 7.5mm at 1500 rpm
or Russian ShKas (1800rpm) would surely be better :-)

Are there any references to the electrical boosting
of the .50s in P51Bs. I've never come across it in
my reading, and can't find any information on it.

XyZspineZyX
07-26-2003, 11:50 PM
Regarding the boost motors. This was a field modification. Some mechanics scrounged booster motors from the ammunition feeds of B-26 medium bombers. They installed these and that cleared up the majority of jams. After this method was proven, the booster motors were installed on as many B's and C's as the supply increased. Also there was one issue of the firing Solenoid freezing at altitude. they discovered this and the solution was to tape and then shelack the firing solenoids so they would not freeze.

Kalo

XyZspineZyX
07-27-2003, 01:19 AM
AaronGT wrote:
- But why use the sledgehammer of the .50 when the
- ball pean of the French Mac 1935 7.5mm at 1500 rpm
- or Russian ShKas (1800rpm) would surely be better
- :-)

Well because there is a limit... So guy way back when pointed that out! /i/smilies/16x16_smiley-wink.gif

- Are there any references to the electrical boosting
- of the .50s in P51Bs. I've never come across it in
- my reading, and can't find any information on it.

Read This:

THE MIGHTY EIGHTH WAR MANUAL
By Roger A. Freeman
ISBN 0-879338-508-1
page 230 paragraph 2 column 2

"A static test carried out in March 1944 by 4th group on a P-51B with flash hider and muzzle BOOSTER attach-ments gave a wider variation. Without any attachments the gun fired 694 rounds per minute. With a flash hider this was reduced to 677 rpm. When the BOOSTER was fitted 857 rpm was obtained but after firing 600 rounds in short bursts the rate rose to 949 rpm."




TAGERT
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If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-27-2003, 04:46 PM
The "Catalogue of Standard Ordnance Items, Second Edition 1944" gives 750-850 rnds/min ROF for the Browning Machinegune Gun, Cal. .50, Aircraft on page 376.

Amunition types: Ball, A.P., tracer, incendinary.


However it also notes:

"Rate of Fire

During training a maximum of 75 rounds is permitted from a cool gun. One minute after firing that burst, firing may be presumed at the rate of one 20-round burst per minute. Combat firing is unrestricted but burst longer than 75 rounds (5-second bursts) will overheat the barrel and if repeated without pause may lead to stoppages and "cooked-off" rounds. Prolonged firing may lead to scrapping the barrel, since a new barrel may be ruined by a prolonged burst of about 1/2 minute duration. After long bursts from synced guns the mechanism must be locked to the rear for two minutes to avoid having "cooked-off" rounds stike the propellor blade.

References TM 9-225, TM 9-1225, TM 9-2200."

http://www.x-plane.org/users/isegrim/FB-desktopweb.jpg
'Only a dead Indianer is a good Indianer!'

Vezérünk a Bátorság, K*sérµnk a Szerencse!
(Courage leads, Luck escorts us! - Historical motto of the 101st Puma Fighter Regiment)

Flight tests and other aviation performance data: http://www.pbase.com/isegrim

XyZspineZyX
07-27-2003, 09:22 PM
tagert wrote:
- Well because there is a limit...

Of course :-)

I'm on the trail of the RAF gunnery manuals and
assessments from 1940-43. Apparently it includes
figures on bullet dispersion (20ft at 400 yards
max grouping for a .303) and a survey of about
800 downed planes and what caused their loss,
plus discussions on relative merits of gun types
based on an analysis of this.

- THE MIGHTY EIGHTH WAR MANUAL
- By Roger A. Freeman
- ISBN 0-879338-508-1
- page 230 paragraph 2 column 2

Thanks.

- With a flash hider this was reduced to 677 rpm. When
- the BOOSTER was fitted 857 rpm was obtained but
- after firing 600 rounds in short bursts the rate
- rose to 949 rpm."

Any indications on what it did to the bullet groupings
at those speeds? The increase in cyclic rate would suggest
that there might have been some mechanism wear, which
might adversely affect accuracy. This being said, it's
more a combination of round density/round power rather
than accuracy per se that is important, but increased
dispersion will tend to decrease bullet density. Does the
increase in dispersion decrease the bullet density faster
than the increased ROF increases it?

At 949rpm you can't afford to take pot shots, by the way -
you are down to about 17 seconds firing time on the outer
pair of guns, which isn't much more than the Tempest V
(13 seconds).

XyZspineZyX
07-27-2003, 09:29 PM
Vo101_Isegrim wrote:
- During training a maximum of 75 rounds is permitted
- from a cool gun. One minute after firing that burst,
- firing may be presumed at the rate of one 20-round
- burst per minute.

Not really a problem in combat fighters, though.
That's equivalent to a 1.6 second burst, or alternatively,
two 0.8 second bursts a minute. You are unlikely to be
in a position to fire more often than that.

What it would mean is that the P40, although designed
as an interceptor to the same spec as the P39 (designed
around a cannon) and the P38 (originally slated for a
23mm Madsen as the main armament) would probably have
had a harder time downing bombers sufficiently quickly
since a long .50 burst might have been contraindicated
(and it only originally carried a pair of these in
addition to the .30s).

XyZspineZyX
07-28-2003, 01:56 AM
AaronGT wrote:
-- THE MIGHTY EIGHTH WAR MANUAL
-- By Roger A. Freeman
-- ISBN 0-879338-508-1
-- page 230 paragraph 2 column 2
-
- Thanks.

NP!

-- With a flash hider this was reduced to 677 rpm. When
-- the BOOSTER was fitted 857 rpm was obtained but
-- after firing 600 rounds in short bursts the rate
-- rose to 949 rpm."
-
- Any indications on what it did to the bullet
- groupings at those speeds?

None, and when you consider it was a static test Im sure they would have noted it.

- The increase in cyclic rate would suggest
- that there might have been some mechanism wear,
- which might adversely affect accuracy.

Doubt it, in that what is really important is how long the busts are maintained, that is where most of the damage would come from.


- This being said, it's more a combination of round
- density/round power rather than accuracy per se
- that is important,

Disagree.

- but increased dispersion will tend to decrease
- bullet density.

increased dispersion would, but not increased rof.

- Does the increase in dispersion decrease the
- bullet density faster than the increased ROF
- increases it?

Doubt it very much.

- At 949rpm you can't afford to take pot shots, by the
- way you are down to about 17 seconds firing time on
- the outer pair of guns, which isn't much more than
- the Tempest V (13 seconds).

Ill bet there were plenty of Tempest pilots that would have killed for 4 most seconds of fire time! /i/smilies/16x16_smiley-wink.gif



TAGERT
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If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-28-2003, 02:50 AM
AaronGT wrote:
-
- Vo101_Isegrim wrote:
-- During training a maximum of 75 rounds is permitted
-- from a cool gun. One minute after firing that burst,
-- firing may be presumed at the rate of one 20-round
-- burst per minute.
-
- Not really a problem in combat fighters, though.
- That's equivalent to a 1.6 second burst, or
- alternatively,
- two 0.8 second bursts a minute. You are unlikely to
- be
- in a position to fire more often than that.

Two 0.8 sec bursts spaced out will not heat the barrel as much as a 1.6 sec burst, heating over time is not linear and at some point the barrel will have cooled down enough from that original 5 second burst to go beyond 1.6 secs but I'd guess it would be quite a while if you keep firing 1.6 secs every minute. Maybe that's one reason they had switches to choose which guns to fire and not just to stretch firing time?

In sims, I find a full half second is a good burst and one full second on target is getting in a lot of insurance.

Cyclic fire... wear? I hope I got that wrong. It's what happens when the springs and bolt are in synch up from dead stop inertia and more or less resonating. An M16 starts out at 600 rpm advertised but hits over half that again before 20 rounds go out if it don't jam, which has more to do with heat and dirt than the design.

You can wear a barrel with a lot of fire and extended bursts. It just makes the later rounds a bit less accurate but since they drag inside the barrel less there will be less heating as well.


Neal

XyZspineZyX
07-28-2003, 08:41 AM
tagert wrote:
-
-
- Another stability problem was due to the centerline
- tank on the D model, The larger tank, when full,
- affected it adversly, so much so that they would
- burn the fuel in the centerline tank (to a point)
- before buring the fule in the drop tanks!
-

What centre line tank? Afaik know the P-51 was not able to carry a centre line tank, only two wing tanks. To carry a centre line tank the inner door covers for the wheels would have to be removed, as was done on the Fw190s.

Now if you meant the internal fuselage tank mounted behind the pilot, yes, it resulted in stability problems when full.

http://www.stenbergaa.com/stenberg/crandall-stormclouds2.jpg

XyZspineZyX
07-28-2003, 10:39 AM
WWMaxGunz wrote:
- Two 0.8 sec bursts spaced out will not heat the
- barrel as much as a 1.6 sec burst,

I know - it was just a quick thing to say. Not
knowning the details of the installations, who
is to know what total length in two bursts matches
1.6 in one burst?

- In sims, I find a full half second is a good burst
- and one full second on target is getting in a lot of
- insurance.
-
- Cyclic fire... wear? I hope I got that wrong.

There has to be some reason for the increase in
cyclic rate. Certainly the .50 was reknowned for
some issues with barrel wear after firing a few
hundred rounds. Firing at a cyclic rate that might
be above the design specs for a few hundred rounds,
with an increase in cyclic rate, might be caused
by a number of things. Wear might be a possibility,
and wear might mean gas leakage and reduction in
muzzle velocity and increased dispersion (along with
the barrel wear) and also perhaps increased vibration
from the higher ROF?

I've seen ROF creep over time in blank firing weapons
we used when doing WW2 reenactment, and that seemed
to be associated with wear of parts, or at the very
least, additional polishing and smoothing of the moving
parts. Wear would be bad, but polishing would be good.
Maybe the ROF increase is a polishing thing.

I'd be concerned that the breech was closed for long
enough to contain the gases if the ROF went too high
as gas leakage from too little time with the breech
closed would definitely adversely affect muzzle velocity,
cause fouling, and put additional strains on the gun.
The .30 is a blowback design, but I am not sure what
the M2 .50 is. Given that the M3 .50 had an ROF close
to the boosted P51B guns then it suggests that excess
gas may not have been an issue, but I suppose it depends
on the tweaks required to create the M3. Maybe it was
an issue, and the M3 needed tweaks to overcome this?
I don't know.

- what happens when the springs and bolt are in synch
- up from dead stop inertia and more or less
- resonating.

Resonance would be a bad thing! That would tend to
cause immense vibration in the gun and it would
get wrecked!

- An M16 starts out at 600 rpm advertised
- but hits over half that again before 20 rounds go
- out if it don't jam, which has more to do with heat
- and dirt than the design.

Maybe I am misreading the quote. I presumed that
it meant that if 600 rounds were fired, then the
rate of fire thereafter was permanently increased.
It mentions 600 rounds in short bursts, so I can't
see inertia being part of the equation.

I wonder what is going on in the M16. It's intriguing.
I'll have to think abotu that one!

- You can wear a barrel with a lot of fire and
- extended bursts. It just makes the later rounds a
- bit less accurate but since they drag inside the
- barrel less there will be less heating as well.

That makes sense.

XyZspineZyX
07-28-2003, 10:43 AM
tagert wrote:
-- Any indications on what it did to the bullet
-- groupings at those speeds?
-
- None, and when you consider it was a static test Im
- sure they would have noted it.

That's good, then.

-- This being said, it's more a combination of round
-- density/round power rather than accuracy per se
-- that is important,
-
- Disagree.

Well, I (and the RAF during WW2) disagree with you!

-- but increased dispersion will tend to decrease
-- bullet density.
-
- increased dispersion would, but not increased rof.

That's why I noted that increased ROF has the opposite
effect to increased dispersion.

- Ill bet there were plenty of Tempest pilots that
- would have killed for 4 most seconds of fire time!

True! The RAF tended to design for fairly short
firing times in fighters, whatever the armament,
though. 10 to 15 seconds was pretty much de rigeour
for single engined RAF fighters of the war.

XyZspineZyX
07-28-2003, 03:53 PM
Aaron, those M2's were used in the field to fire 1000's and 1000's of rounds and still worked as long as they were not fired in too long a burst. 1000's of rounds in a single prolonged battle, sometimes 1000's in a single day at least with M2's on the ground. The sergeant who taught me radar had been a marine machinegunner in Korea and attested to firing all night many nights during human wave attacks and they only had two barrels to change back and forth for their gun. Browning ran tests for the government on every gun type sold and that company had a solid reputation for reliability.

The M16A1 goes cyclic in less than 20 rounds of steady autofire. 600 rpm is the rate of fire from the start just between the 1st and 2nd round. You pull the trigger and let it go as fast as you can and 2 or 3 shots have gone off right then. With a cool, clean rifle you can fire off 20 rounds in less than 2 seconds time easy. It don't have the power of a 7.62 but even a car is not considered cover from an M16, those bullets pack 1100 ft-lbs at muzzle!

No, going cyclic does not wear the guns out quickly. these are precision machined and balanced tools. If anything, the pre-cyclic rounds are going to have parts with more misaligned forces than when everything is flowing. That is how cyclic fire rates get their great speed, the parts are jumping in line so nicely. In the case of the M16 and all gas operated guns, the bolt goes back when the gas in the barrel tapped near the very end of the barrel goes back to operate the bolt. The bullet is out and gone by the time the barrel is beginning to open. I believe the M2 is the same but maybe not. Browning was good about that, but the MG34, MG42 and Russian MG's were better for speed.

Cyclic rates are and were hit quite often without destroying the guns in short time. You want fun about wear and tear... I know vets who ran MG's in combat to where the barrels were white-hot before they had a chance to change them. I've been told a number of times that you could see the bullets firing through the inside of the barrels from outside. Those barrels were write-offs. The red-hots; for an M60 7.62mm medium MG you have an abspestos mitt, you turn a crank and pull the barrel out then put in your cool barrel. When that is hot, you change back again. This was done again and again without needing new barrels.

You have to take care about ROF numbers for guns since some people may feed you cyclic rates to compare to other guns' starting rates or where they should be quoting synchronized rates (don't those change with prop speed?).

What happens to worn guns? They sell some off (you can still buy M1's) or use them for training and when they are worn out for that... I guess that is what you guys fire blanks with? Don't the blank plastics build up behind those adapters?


Neal

XyZspineZyX
07-28-2003, 04:34 PM
MiloMorai wrote:
- Now if you meant the internal fuselage tank mounted
- behind the pilot, yes, it resulted in stability
- problems when full.

Roger the internal fuselage tank, the one in the CENTER, and not WING tanks, you know the tanks that can NOT be drop, thus not called DROP TANKS! /i/smilies/16x16_smiley-wink.gif




TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-28-2003, 04:46 PM
AaronGT wrote:
--- Any indications on what it did to the bullet
--- groupings at those speeds?
--
-- None, and when you consider it was a static test Im
-- sure they would have noted it.
-
- That's good, then.

It is good, and make sense... common sense really.

- That's why I noted that increased ROF has the
- opposite effect to increased dispersion.

Noted? You mean Guessed right? Thus you shouldn't state it like it is FACT, that increasing ROF would increase the DISPERSION. BUT.. let me play that game and let's ASSUME that it is TRUE.. Now the only question left is how much DISPERSION would it cause?

At this point you have to use a little more common sense. Now Im sure you have seen the pictures of the static convergance tests ground crews did? You know where they prop up the rear of the plane and shoot at some targets to check the convergance. Now.. dont you think that after such a mod in the field someone would have check the convergance after such a mod... and had the DISPERSION been a problem Im sure they would have removed the mod, or found another method... But they didnt, thus I think it is safe to assume that the DISPERSION was not a problem due to a greater ROF.



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-28-2003, 05:41 PM
The centreline tanks are in most cases drop tanks./i/smilies/16x16_smiley-wink.gif (the Spit could mount an external centreline tank that was not dropable) A bad word choice on your part./i/smilies/16x16_smiley-wink.gif

http://www.stenbergaa.com/stenberg/crandall-stormclouds2.jpg

XyZspineZyX
07-28-2003, 05:44 PM
tagert wrote:
-- That's why I noted that increased ROF has the
-- opposite effect to increased dispersion.
-
- Noted? You mean Guessed right?

No guess. I used my brain. I have a degree in theoretical
physics and a masters in computer science, so while I
am prepared to use first approximations and suppositions and models to examine something, wild guesses aren't really
my style.

- Thus you shouldn't
- state it like it is FACT, that increasing ROF would
- increase the DISPERSION.

Just as well I didn't then. I mentioned that I would
be concerned that there might be a possibility of
increased dispersion, and suggested some mechanisms
by which increased dispersion migh occur. I certainly
didn't suggest that increased dispersion was a certainty.

- At this point you have to use a little more common
- sense. Now Im sure you have seen the pictures of the
- static convergance tests ground crews did? You know
- where they prop up the rear of the plane and shoot
- at some targets to check the convergance. Now.. dont
- you think that after such a mod in the field someone
- would have check the convergance after such a mod...

They may well have done, and probably did. But if the
bullet density was increased sufficiently, it wouldn't
really matter, and they may not have noted it.

- and had the DISPERSION been a problem Im sure they
- would have removed the mod,

If the dispersion was (and I am not saying it is - you
seem to treat what I am throwing out as possibilties
as some kind of statement as belief that these possibilities
are facts, which somewhat confuses me) such that
bullet density was decreased in the target area, then
they would have removed it for sure.

It's entirely possible that dispersion was increased,
but bullet density, due to increased ROF was increased.
It is also possible that there was no increase in dispersion. I merely suggested that I wouldn't be surprised,
that with increased mechanical stress on the components,
that increased dispersion was a possibility. The increase
in dispersion might be negligible anyway.

If the ROF increase beats any increase in dispersion
then all is well.

- method... But they didnt, thus I think it is safe to
- assume that the DISPERSION was not a problem due to
- a greater ROF.

That seems a fair assessment to me too.

I would guess, though, that the extra complexity of the
installation (and weight, etc) wasn't worth continuing
with as a field mod when six gun Mustangs became available,
else the field mod would have continued. It would seem
that effort was expended on creating the M3 .50, but
I don't know if that was started before or after the
P51B experiments and field mods.

XyZspineZyX
07-28-2003, 06:07 PM
Vo101_Isegrim wrote:
-
- The "Catalogue of Standard Ordnance Items, Second
- Edition 1944" gives 750-850 rnds/min ROF for the
- Browning Machinegune Gun, Cal. .50, Aircraft on page
- 376.
-
- Amunition types: Ball, A.P., tracer, incendinary.
-



Now this giives me a one hell of an idea.....

"Amunition types: Ball, A.P., tracer, incendinary."

Wouldn't it be rather cool if we could select our own Ammo types in the arming screen?



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XyZspineZyX
07-28-2003, 09:54 PM
WWMaxGunz wrote:
- The M16A1 goes cyclic in less than 20 rounds of
- steady autofire.

The regulatory mechanisms in the gun should, in theory,
keep the rate constant. If it increases then something
must happen to make it change. If it is a gas operated
mechanism, then I can see that increased gas pressure
in the cylinder might be a reason for this. The M2
is blowback operated, though. Maybe there is a gradual
increase in pressure in the barrel as firing continues
and this might increase the force of blowback? It's an
alternative to the wear/polishing idea if that's implausible.

My experience of firing WW2 weapons is relegated
to firing blanks, but they certainly showed no
tendency to increase in ROF during a magazine, just
a tendency for some to slightly increase in ROF
over several hundred rounds (non continuous firing).
It's not a scientific study though - these were guns
ranging from 40 to almost 70 years old at the time.

- the bolt goes back when the gas
- in the barrel tapped near the very end of the barrel
- goes back to operate the bolt. The bullet is out
- and gone by the time the barrel is beginning to
- open.

That's not the point. The point is that the
barrel is has hot gases in from firing. THe sooner
it is opened, the more dangerous these are, hence
the need for delayed blowback, locking mechanisms, etc.
Things that the M16 employs, and that taxed the developers
of automatic weapns until they got it right. (That
and initially powders didn't burn cleanly enough - which
was the downfall of the first assault rifle in 1895).

Also you don't want to increase the cyclic rate of a
gas-operated gun too much above it's design specs.

- I believe the M2 is the same but maybe not.

The M2 is blowback, like the M1919 .30. (I had to go and
check if the M2 was blowback like its smaller
brother).

- what you guys fire blanks with? Don't the blank
- plastics build up behind those adapters?

Not that I was ever aware of. Our unit BAR man used
to fire anything up to a couple of hundred rounds in
one day, which was several weeks worth for those with
M1s. The only time it ever jammed was when a friend
cleaned it and loaned it to me for use that day.
It misfired on every round. I suspect it wasn't
reassembled correctly.

Some fired crimped
rounds (intended for firing grenades I think) rather
than the flat nosed ones, though, but that was because
they felt they fed better. The closure for the non
crimped rounds from the mostly 1950s vintage ones
we were firing in the 1980s were card/thick paper.
Some of the more lax people (sadly including our
squad leader) never cleaned the guns and had jams.
My best friend cleaned his, but never removed the blank
adapter and never had one jam from his M1 in several
hundred rounds fired, so I don't think the blank adapters
were particularly prone to clogging.

I had an M1917 and M1903 - no blank adaptor.

XyZspineZyX
07-29-2003, 12:55 AM
MiloMorai wrote:
- The centreline tanks are in most cases drop
- tanks.

Agreed.

- (the Spit could mount an external centreline
- tank that was not dropable)

True.

- A bad word choice on your part.

Disagree! /i/smilies/16x16_smiley-wink.gif


TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 01:23 AM
AaronGT wrote:
- No guess. I used my brain.

Ah, a WAG then! /i/smilies/16x16_smiley-wink.gif

- I have a degree in theoretical physics and a
- masters in computer science,

I have a dog with a cold nose!

- so while I am prepared to use first approximations
- and suppositions and models to examine something,
- wild guesses aren't really my style.

Disagree! /i/smilies/16x16_smiley-wink.gif

- Just as well I didn't then.

Really?

- I mentioned that I would be concerned that there
- might be a possibility of increased dispersion,
- and suggested some mechanisms by which increased
- dispersion migh occur. I certainly didn't suggest
- that increased dispersion was a certainty.

Disagree.

-
-- At this point you have to use a little more common
-- sense. Now Im sure you have seen the pictures of the
-- static convergance tests ground crews did? You know
-- where they prop up the rear of the plane and shoot
-- at some targets to check the convergance. Now.. dont
-- you think that after such a mod in the field someone
-- would have check the convergance after such a mod...
-
- They may well have done, and probably did.

May and Probably? Huh, well I did note it takes commn sense to realise they did.

- But if the bullet density was increased sufficiently,
- it wouldn't really matter, and they may not have
- noted it.

Like I said, only a question of HOW MUCH DISPERSION. And the fact that they didnt note it implys that it was so small.. IF ANY that it was not worth worrying about. Or are you asking me to belive there was a chance that it was really BAD and they decided to just go with it anyways? And that it was really BAD... yet no pilots make much note of it? Is that what your asking me to buy into?

- If the dispersion was

- (and I am not saying it is you seem to treat what
- I am throwing out as possibilties as some kind of
- statement as belief that these possibilities are
- facts, which somewhat confuses me)

Is how it came off, yes.

- such that bullet density was decreased in the
- target area, then they would have removed it
- for sure.

So you agree that if there was any, it was so small that it didnt mater?

- It's entirely possible that dispersion was
- increased, but bullet density, due to increased
- ROF was increased.

Ah, so maybe I dont understand what you mean by DISPERSION? I take that to mean a bigger spread of the bullets on the target, that is a bigger radis? Impling that the bigger ROF had some harmonic of the barrel/recoil would cause the bullet to land farther away from the aim point then with a lower ROF? Is that what you mean by bullet DISPERSION? Assuimg that IS WHAT YOU MEAN, then it would be VERY APPARETN at the end of a static convergance test that the bullets are hitting all over the place with the mod as opposed to without the mod... but you still think such a test would have been a MAYBE or a PROBABLY, so I can see where you might initally think there might have been a DISPERSION problem.

- It is also possible that there was no increase in
- dispersion. I merely suggested that I wouldn't be
- surprised,

Funny, but in your inital post you made the suttle statment and then carried on as if it was fact.. But maybe it is just me being hyper sensitive to your style of writing?

- that with increased mechanical stress on the
- components, that increased dispersion was a
- possibility.

I think your FORGETTING ONE THING! These mods were used on .50cal on BOMBERS.. That is to say they didnt take an electric motor booter off of a TRUCK and mount it on a .50 cal. The electric motor was DESIGNED for the .50 cal, just not initally intended for use on the P51B. Thus not mechanical stress on the componets, and no increased dispersion, in that gunners on the bombers would have complied too about dispersion problems.

- The increase in dispersion might be negligible anyway.

Im sure it was! In that Im sure they did a static test of the mod to prove it to them selfs... And if they didnt to a specific test to prove it to them selfs, Im sure that the next time the P51B went in for a static test to calibrate the convergance they would have at least noticed a bigger radis/spread of the hits... ie DISPERSION.

- If the ROF increase beats any increase in dispersion
- then all is well.

No need to beat it, it probally wasnt there, and if it was, probally so small that no one noticed it.

- That seems a fair assessment to me too.

Yup! /i/smilies/16x16_smiley-wink.gif

- I would guess, though, that the extra complexity of
- the installation (and weight, etc) wasn't worth
- continuing with as a field mod when six gun Mustangs
- became available, else the field mod would have
- continued.

Wasnt that complex, most field mods Aint! /i/smilies/16x16_smiley-wink.gif Now I may be wrong about this, but I dont think I am, The mod was not to increase the ROF, that was a bi-product of the mod, the mod was intended to fix the jamming problem P51B's had due to the cockeyed placement of the .50s and the ammo feeds to them, the ammo had to go OVER a big hump in the wing strut, on the P51D's that area was redesigned to accomidate the 6x.50s and that hump was fixed in that process.


- It would seem that effort was expended on creating
- the M3 .50, but I don't know if that was started
- before or after the P51B experiments and field mods.

Not sure what your taking about, thus no comment! /i/smilies/16x16_smiley-wink.gif


TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 01:30 AM
Yes, a bad choice of a word by you./i/smilies/16x16_smiley-wink.gif

Do a/c such as the 109, 190, Spit, Hurrie, which had fuselage fuel tanks, are they called 'centreline' tanks? No. Only those tanks mounted outside the airframe and below the fuselage were called 'centreline' fuel tanks.


tagert wrote:

-
-- A bad word choice on your part.
-
- Disagree!

http://www.stenbergaa.com/stenberg/crandall-stormclouds2.jpg

ZG77_Nagual
07-29-2003, 01:31 AM
You might see increased dispersion if there barrels got too hot - from a higher rof during long bursts - seems unlikely in this context - but there was the phenomenon of 'muzzle whip' on the m-16 - where the barrel would get so hot that the torque of the spinning round and recoil would cause it to move a bit. Like I said - doubtful in this context.

http://pws.chartermi.net/~cmorey/pics/p47janes.jpg

XyZspineZyX
07-29-2003, 01:40 AM
MiloMorai wrote:
- Yes, a bad choice of a word by you.

Ok Ok I give! Your right! Bad Choice! /i/smilies/16x16_smiley-wink.gif



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 01:41 AM
ZG77_Nagual wrote:
- You might see increased dispersion if there barrels
- got too hot - from a higher rof during long bursts -
- seems unlikely in this context - but there was the
- phenomenon of 'muzzle whip' on the m-16 - where the
- barrel would get so hot that the torque of the
- spinning round and recoil would cause it to move a
- bit. Like I said - doubtful in this context

Roger, we noted that, and are assuming short bursts and such.. But MAX brought up a good point, as the barrel gets hotter, expansion, thus less drag... So the only thing Im sure about is that Im not sure what would happen in the non recomended long burst dept! /i/smilies/16x16_smiley-wink.gif



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 05:15 AM
Centerline is standard aircraft nomenclature for a droppable tank mounted on the center line of the airframe.

On the subject of machine guns, all machineguns require care when firing, lest they wear their barrels. This is not confined to the Browning 0.50. Even modern multibarrel gattling guns will destroy themselves after a few seconds of firing time.

The MG42's barrel, for example, only lasts around 250-300 rounds before requiring changing, or about 10 seconds of total firing time before the barrel is effectively destroyed. That's part of hte reason they weren't suitable for aircrat mountings.

I am told by a friend of mine who used to be in the army, if they had a 0.50 barrel that was nearing the end of its operational lif time, but wasn't quite dead enough they could justify replacing it, they would take the gun down to the range, and fire off a full 100 round box, then pull the barrel out, and put it on a rock to cool. The barrel would be so hot, it would actually bend over the rock before it cooled. Once it cooled they'd just take the bent barrel down to the depot for replacement.

From what I have read, the jamming problem the P-51B had was caused by the wing being to thin to mount the guns in upright, so the guns were mounted at an angle, causing a kink in the feed mechanism. The kink would sometimes catch a round and hold onto it, preventing the gun from feeding properly.

The early F4F's also had problems with guns jamming. That aircraft had 450 round belts, and in negative 'G' manuvers, they would lift up in the ammo boxes, and when potitive 'G's returned, they would not always settle back down correctly. That was solved by simply installing dividers in the ammo boxes.

One additional jamming problem that some American fighters had was caused by burrs in the ammo bins. Sometimes ammo belts would snagg on the burrs and again, prevent the gun from feeding correctly. I think that was solved by either switching to stainless steel ammo bins, or by improving manufacturing processes. I don't recall which. Perhapse it was both?

An, additionally on the subject of the P-51B, I personally would be more exited to se a Mustang Mk IA's with Allison engines and the four Hispano 20mm cannon armament. That aircraft would be perfect for FB.

Harry Voyager

http://groups.msn.com/_Secure/0YQDLAswcqmIpvWP9dLzZVayPXOmo6IJ16aURujNfs4dDETH84 Q6eIkCbWQemjqF6O8ZfvzlsvUUauJyy9GYnKM6!o3fu!kBnWVh BgMt3q2T3BUQ8yjBBqECLxFaqXVV5U2kWiSIlq1s6VoaVvRqBy Q/Avatar%202%20500x500%20[final).jpg?dc=4675409848259594077

XyZspineZyX
07-29-2003, 05:23 AM
HarryVoyager wrote:
- Centerline is standard aircraft nomenclature for a
- droppable tank mounted on the center line of the
- airframe.

Centerline in the drafting world is standard nomenclature for things in and around the middle/center of something. /i/smilies/16x16_smiley-wink.gif Took 3 years of drafting in high school! /i/smilies/16x16_smiley-wink.gif

- I am told by a friend of mine who used to be in the
- army, if they had a 0.50 barrel that was nearing the
- end of its operational lif time, but wasn't quite
- dead enough they could justify replacing it, they
- would take the gun down to the range, and fire off a
- full 100 round box, then pull the barrel out, and
- put it on a rock to cool. The barrel would be so
- hot, it would actually bend over the rock before it
- cooled. Once it cooled they'd just take the bent
- barrel down to the depot for replacement.

True! Been there done that!

- From what I have read, the jamming problem the P-51B
- had was caused by the wing being to thin to mount
- the guns in upright, so the guns were mounted at an
- angle, causing a kink in the feed mechanism. The
- kink would sometimes catch a round and hold onto it,
- preventing the gun from feeding properly.

Roger they were mounted cockeyed.. ie at an angle, but I also read once that and a hump the ammo had to lay over contributed to the jamming.

- An, additionally on the subject of the P-51B, I
- personally would be more exited to se a Mustang Mk
- IA's with Allison engines and the four Hispano 20mm
- cannon armament. That aircraft would be perfect for
- FB.

Yup when you consider that 99 out of 100 online games never get above 10k because the bases are so close that you could toss a rock to the other.. the MkIA would be perfect, in that teh Allison was not bad at low alt.



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 01:21 PM
tagert wrote:
- HarryVoyager wrote:
-- Centerline is standard aircraft nomenclature for a
-- droppable tank mounted on the center line of the
-- airframe.
-
- Centerline in the drafting world is standard
- nomenclature for things in and around the
- middle/center of something. Took 3 years of drafting in
- high school!


Well, from your description, you failed your highschool drafting./i/smilies/16x16_smiley-wink.gif

'Centreline' is not 'in and around' but a precise line. IT IS THE 'axes of symetrical objects or features, bolt circles, paths of motion'. (had to dig out my old college drafting text book for that/i/smilies/16x16_smiley-wink.gif )

Now which fuselage centreline is this tank mounted on, the horizontal centreline or the vertical centreline?


Harry, too bad Mr PhD could not just simply admit, from the start, he used the wrong word, >>> without the extra diarreha <<<.

http://www.stenbergaa.com/stenberg/crandall-stormclouds2.jpg

XyZspineZyX
07-29-2003, 03:37 PM
tagert wrote:
-- so while I am prepared to use first approximations
-- and suppositions and models to examine something,
-- wild guesses aren't really my style.
-
- Disagree! /i/smilies/16x16_smiley-wink.gif
-
-- Just as well I didn't then.

You need to distinguish between something mentioned
as a possibility, and something being claimed as a
fact.

-- I mentioned that I would be concerned that there
-- might be a possibility of increased dispersion,
-- and suggested some mechanisms by which increased
-- dispersion migh occur. I certainly didn't suggest
-- that increased dispersion was a certainty.
-
- Disagree.

I know what I said.

- Like I said, only a question of HOW MUCH DISPERSION.

Yep, which is why I mentioned that it was a question
of how much disperion. I noted that dispersion and
ROF pull in different directions in terms of the
bullet density at the target area. Obviously how
much of each is important.

- And the fact that they didnt note it implys that it
- was so small.

Or the net effect was to improve bullet density, which
was a positive result all the same. Without detailed
figures we don't know what the effect on dispersion
or bullet density was, but we can surmise that the
improvement was positive. We can't treat it as fact
necessarily, as omission is not the same as proof.
We can only make an assumption, but it is probably
a fair one.


- about. Or are you asking me to belive there was a
- chance that it was really BAD and they decided to
- just go with it anyways?

No, and I never suggested it. All I did was mention
that dispersion might have been increased. If I gave
the impression that I was suggesting that I thought
that bullet density would have been decreased due to
this dispersion despite the increased ROF then I am
sorry. It was not my intention. It was just a side
note that I wondered/suspected there might be some
level of increased dispersion, of an unknown extent.

- BAD... yet no pilots make much note of it? Is that
- what your asking me to buy into?

No. You seem to be reading that into what I said, but
it isn't what I intended.

- Is how it came off, yes.

I apologise then. That is not what I intended to imply,
or allow room for that inference.


- Ah, so maybe I dont understand what you mean by
- DISPERSION? I take that to mean a bigger spread of
- the bullets on the target, that is a bigger radis?

Absolytely.

- Impling that the bigger ROF had some harmonic of the
- barrel/recoil would cause the bullet to land farther
- away from the aim point then with a lower ROF?

There could be increased vibration, unequal or unintended
pressure variations, etc. All manner of possibilities.
It depends on the action of the .50 in detail, and how
being pushed a bit outside its manufacturing tolerances
might affect it. Or the .50 might be able to cope with
a higher rate of fire without adverse effects. In
a wing mounting higher vibration, and any increased
dispersion, might not be significant compared to the
wing shake experienced from firing a standard ROF
weapon.

- that what you mean by bullet DISPERSION? Assuimg
- that IS WHAT YOU MEAN, then it would be VERY
- APPARETN at the end of a static convergance test
- that the bullets are hitting all over the place with
- the mod as opposed to without the mod...

It may have been apparent, or they may have been
looking for an increased bullet density towards the
centre of the target. If this was achieved they may
not have bothered to note any increased dispersion
as the required result (increased bullet density on
the target) would have been achieved.

Given that it was considered apparently worthwhile
to continue with the field mod until six gun Mustangs
came on line, we can surmise that improved bullet density
was achieved. From this we can secondarily infer that
the dispersion was such that the bullet density did
not decrease, and with figures for bullet dispersion
from a standard .50 in an equivalent mount, we could
put upper bounds on what the dispersion could be. If we
had a .50 and some motors we could test the dispersion
in a new experiment, but we might arouse the attention
of the police!

-- It is also possible that there was no increase in
-- dispersion. I merely suggested that I wouldn't be
-- surprised,
-
- Funny, but in your inital post you made the suttle
- statment and then carried on as if it was fact..
- But
- maybe it is just me being hyper sensitive to your
- style of writing?

I think it might be.

- I think your FORGETTING ONE THING! These mods were
- used on .50cal on BOMBERS..

The situation for bomber guns is rather different for
fighters. Bomber defensive guns were wildly inaccurate,
and the method was essentially to fill the air with
a sufficient quantity of bullets that even given the
extreme dispersion and inaccuracy of hand held mounts,
with enough guns an enemy fighter was likely to be hit.
In this instance increasing the ROF is a good route
for this. If the ROF mod increased the dispersion a bit it
wouldn't matter as dispersion was already very high.

In a fighter mount dispersion is rather lower.


-- It would seem that effort was expended on creating
-- the M3 .50, but I don't know if that was started
-- before or after the P51B experiments and field mods.
-
- Not sure what your taking about, thus no comment!

The M3 .50 was developed at the end of the war, just
clipping the end of it. It was a higher rate of fire
.50 calibre, which saw service in some later war P51s,
and of course the F86.

ZG77_Nagual
07-29-2003, 04:03 PM
As has been mentioned - the fuel tank in question is not a centerline tank - but a fusilage tank mounted behing the cockpit - of course technically it was along the front to back centerline - but it is not a drop tank but an internal fuel tank which, when fullish - messed with the aircraft's center of gravity. It was NOT jettisonable but they did make a point of using it first before entering combat on long missions.

I hope we can stop arguing about it. It was just a simple ambiguity in terms.

http://pws.chartermi.net/~cmorey/pics/p47janes.jpg


http://pws.chartermi.net/~cmorey/pics/p47janes.jpg

XyZspineZyX
07-29-2003, 04:38 PM
Which Spit carried a non dropable external tank on the centreline? I'm aware of the Mk II experiment with a single fixed tank attached to one wing, but as far as I know all the centre external tanks on Spits were dropable, even the 170 gallon.

ZG77_Nagual
07-29-2003, 05:22 PM
I thought we were on about mustangs /i/smilies/16x16_smiley-happy.gif
don't know from spits - though I sure would like that clipped mkxiv that feival has built for FB

http://pws.chartermi.net/~cmorey/pics/p47janes.jpg

XyZspineZyX
07-29-2003, 07:31 PM
MiloMorai wrote:
- Well, from your description, you failed your
- highschool drafting.

LOL!

-'Centreline' is not 'in and around' but a precise
- line. IT IS THE 'axes of symetrical objects or
- features, bolt circles, paths of motion'. (had to
- dig out my old college drafting text book for
- that)

Yeah I had to dumb it down from that hard line discription.

- Now which fuselage centreline is this tank mounted
- on, the horizontal centreline or the vertical
- centreline?

Depends on what you consider to be the horizontal and vertical! /i/smilies/16x16_smiley-wink.gif


TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 09:02 PM
ZG77_Nagual wrote:
- As has been mentioned - the fuel tank in question is
- not a centerline tank - but a fusilage tank mounted
- behing the cockpit - of course technically it was
- along the front to back centerline

Thank You!

- but it is not a drop tank but an internal fuel
- tank which,

Exactally!

- when fullish - messed with the aircraft's center of
- gravity.

Yup, was my inital point that got lost in the whole centerline debate! /i/smilies/16x16_smiley-wink.gif

- It was NOT jettisonable but they did make a
- point of using it first before entering combat on
- long missions.

Actually it is even stranger than that... The idea with drop tanks in general is to use the fule in them FIRST.. because you dont know when you might get jumpped and thus have to drop them... The stability problem was so bad in the P51D's that they would actually burn off the fule in the centerline... I mean fusalage tank behind the seat FIRST to the point where the problem was gone, then swithc to buring the fule in the drop tanks.

- I hope we can stop arguing about it. It was just a
- simple ambiguity in terms.

Agreed! My bad, but I think most understood what I meant, only a few missed it.



TAGERT
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If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-29-2003, 10:25 PM
Well if you really had highschool drafting you would know the plan view is the horizontal. The side view is the vertical.

Why don't you just use the correct word >> fuselage tank? But since you have to 'dumb down', it is undestandable why you don't.

OBW, the fuselage tank, or for you, centreline tank/i/smilies/16x16_smiley-wink.gif , was not completely emptied. When the tank was down to 20-30 gal., the wing drop tanks were then used.

http://www.stenbergaa.com/stenberg/crandall-stormclouds2.jpg

XyZspineZyX
07-31-2003, 02:03 AM
MiloMorai wrote:
- Well if you really had highschool

Well it was 30 years ago, not ment as an excuse, just a explanation. If you dont use things very often, you tend to loose them

- drafting you would know the plan view is the
- horizontal. The side view is the vertical.

But first and formost I would have to give a rats a$$! /i/smilies/16x16_smiley-wink.gif

- Why don't you just use the correct word >> fuselage
- tank?

Because centerline is not so wrong.

- But since you have to 'dumb down', it is
- undestandable why you don't.

Yes, very understandable, but dont be too hard on yourself, there are lots of people that benifit from it.

- OBW, the fuselage tank, or for you, centreline
- tank was not completely emptied. When the tank
- was down to 20-30 gal., the wing drop tanks were
- then used.

Note I never said it was completely emptied, I even went as far as to note that it wasnt... Im getting the impression that I may need to do some more dumbing down? Or did you just miss that part of my post? /i/smilies/16x16_smiley-wink.gif


TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-31-2003, 02:42 AM
AaronGT wrote:
- You need to distinguish between something mentioned
- as a possibility, and something being claimed as a
- fact.

Right back at chaa! /i/smilies/16x16_smiley-wink.gif

- I know what I said.

I know what I read.

- Yep, which is why I mentioned that it was a question
- of how much disperion. I noted that dispersion and
- ROF pull in different directions in terms of the
- bullet density at the target area. Obviously how
- much of each is important.

See... right there, you didn't point out that you *THINK* or *FEEL* or *BELIVE* that ROF pulls in a different direction in terms of bullet density, you just stated it like it is fact.

-- And the fact that they didn't note it implys that it
-- was so small.
-
- Or the net effect was to improve bullet density,
- which was a positive result all the same.

How can you have increased DISPERSION and at the same time have improved bullet DENSITY?

- Without detailed figures we don't know what the effect
- on dispersion or bullet density was, but we can surmise
- that the improvement was positive.
- We can't treat it as fact necessarily, as omission is
- not the same as proof.

Surmise.. is that a fancy way of saying "use common sense"?


- We can only make an assumption, but it is probably
- a fair one.

Probably a very very VERY fair one.

- No, and I never suggested it.

Was implied.

- All I did was mention that dispersion might have been
- increased.

So.. now it is might.. but above you said, and I quote

- "I noted that dispersion and ROF pull in different
- directions in terms of the bullet density at the
- target area."

Note you didn't say, there is a *CHANCE* that with increased ROF there may be a decrease in bullet density.

- If I gave the impression that I was suggesting that I
- thought that bullet density would have been decreased
- due to this dispersion despite the increased ROF then
- I am sorry.

No need to be sorry, we are just closing the loop on things... Good engineers and scientist do that, they make a statement, and don't assume it was received, they ask the person(s) to restate it back to ensure they are both on the same sheet of music.

- It was not my intention. It was just a side
- note that I wondered/suspected there might be some
- level of increased dispersion, of an unknown extent.

Fine, just wanted to point out to you that it came off that way.. A perfect example is what you said above, i.e. the dif directions statement.

- No. You seem to be reading that into what I said,
- but it isn't what I intended.

No, it is just my way of pointing out how silly it is to think it was BAD, in that someone, be it the mechanic at convergence testing, or the pilot after a sortie seeing his tracers all over the place... it would have been apart and talked about by someone.

- I apologise then. That is not what I intended to
- imply, or allow room for that inference.

No need to apologize either, just closing the loop here, ASKING for clarification on some things and letting you know how I interpreted your statements, all in the hopes of understanding.

-- Ah, so maybe I don't understand what you mean by
-- DISPERSION? I take that to mean a bigger spread of
-- the bullets on the target, that is a bigger radis?
-
- Absolytely.

Ah, good, I know it was a DUH... but I just wanted to clear that up from the start, in that if we are not on the same sheet of music with that basic notion, then the rest of the conversation is worthless.

-- Impling that the bigger ROF had some harmonic of the
-- barrel/recoil would cause the bullet to land farther
-- away from the aim point then with a lower ROF?
-
- There could be increased vibration, unequal or
- unintended pressure variations, etc. All manner of
- possibilities.

Agreed, could be, but, it appears there wasn't, in that had there been they would have removed the mod. In that I don't see how you can have IMPROVED bullet density and INCREASED dispersion at the same time?

- It depends on the action of the .50 in detail, and
- how being pushed a bit outside its manufacturing
- tolerances might affect it. Or the .50 might be able
- to cope with a higher rate of fire without adverse
- effects.

I think I should point this out again, the electric motors were designed for use with the .50 MG! They were initially designed for bombers .50 MG, and were applied to the P51B's .50 MG as a field MOD. That is to say this electric motor was not designed for use on a windshield wiper or a dish washer.. it was designed to be used on/with the .50 MG.

- In a wing mounting higher vibration, and any increased
- dispersion, might not be significant compared to the
- wing shake experienced from firing a standard ROF
- weapon.

Agreed.

- It may have been apparent, or they may have been
- looking for an increased bullet density towards the
- centre of the target. If this was achieved they may
- not have bothered to note any increased dispersion
- as the required result (increased bullet density on
- the target) would have been achieved.

Ah, ok, now your semi qualifying your def of how you can have improved bullet density and increased dispersion at the same time. Problem is I don't buy it! /i/smilies/16x16_smiley-wink.gif

- Given that it was considered apparently worthwhile
- to continue with the field mod until six gun
- Mustangs came on line, we can surmise that improved
- bullet density was achieved.
- From this we can secondarily infer that
- the dispersion was such that the bullet density did
- not decrease,

Disagree, in that it there is a 3rd case, no IMPROVEMENT in bullet density at all and no INCREASE in dispersion. Keep in mind the mod was NOT to address density or dispersion, it was to address the jamming problem. The higher ROF was just a bi-product of the jam fix mod.

- and with figures for bullet dispersion
- from a standard .50 in an equivalent mount, we could
- put upper bounds on what the dispersion could be. If
- we had a .50 and some motors we could test the
- dispersion in a new experiment, but we might arouse the
- attention of the police!

The probability is HIGH on that! /i/smilies/16x16_smiley-wink.gif

-- I think your FORGETTING ONE THING! These mods were
-- used on .50cal on BOMBERS..
-
- The situation for bomber guns is rather different
- for fighters.

YOUR MISSING THE MAIN POINT!! It was designed for the fifty cal!!! Thus all the issues you originally raised are not issues at all!! It was made for the .50 MG.

- Bomber defensive guns were wildly inaccurate,
- and the method was essentially to fill the air with
- a sufficient quantity of bullets that even given the
- extreme dispersion and inaccuracy of hand held
- mounts, with enough guns an enemy fighter was likely
- to be hit.

DID I JUST HEAR YOU SAY THAT WITH ENOUGH GUNS (i.e. MORE GUNS) AN ENEMY FIGHTER WAS LIKELY TO BE HIT? FUNNY... THERE WAS A GUY SAYING SOMETHING LIKE THAT WITH REGARDS TO 8x0.50 vs 6x AND 4x... WHO WAS THAT BRILLIANT GUY AND WHERE DID I READ THAT? /i/smilies/16x16_smiley-wink.gif

- In this instance increasing the ROF is a good route
- for this. If the ROF mod increased the dispersion a
- bit it wouldn't matter as dispersion was already very high.

For bombers yes, never said it wasn't, my only point there was to point out that the electric motor was designed to work with the .50 cal, thus all your worries about it damaging the gun were null and void.

- In a fighter mount dispersion is rather lower.

If any at all.

- The M3 .50 was developed at the end of the war, just
- clipping the end of it. It was a higher rate of fire
- .50 calibre, which saw service in some later war
- P51s, and of course the F86.

Ah, ok.



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-31-2003, 06:13 AM
I have never seen so much manure being spread as that which is coming from you. You should do something about that diarreha.


The 85gal tank, just filling in some details, you left out./i/smilies/16x16_smiley-happy.gif


OBW, the 190 and 109 used their centreline 300 l. tank first and then switched to the fuselage fuel tanks, err, for you, that is the fuselage horizontal/plan centreline fuel tank.



http://www.stenbergaa.com/stenberg/crandall-stormclouds2.jpg

XyZspineZyX
07-31-2003, 04:23 PM
tagert wrote:
- See... right there, you didn't point out that you
- *THINK* or *FEEL* or *BELIVE* that ROF pulls in a
- different direction in terms of bullet density, you
- just stated it like it is fact.

Maybe I wasn't as clear with my language as I should
have been, and this is probably a useful "heads up"
for me that I might give the wrong impression about
my uncertainty when I mention things.

-
--- And the fact that they didn't note it implys that it
--- was so small.
--
-- Or the net effect was to improve bullet density,
-- which was a positive result all the same.
-
- How can you have increased DISPERSION and at the
- same time have improved bullet DENSITY?

Due to increase in rate of fire. If the rate of fire
increases, but the dispersion of each round is greater,
then it is possible for bullet density to be higher.
This is one of the possible scenarios for the boosted
P51B guns - some increased dispersion, but the increase
in rate of fire outweighing this. Or there may have
been no increase in dispersion. I was basically just
originally the possibility of increased dispersion, and
in _general_ increased rate of fire does offer mechanisms
for increasing dispersion. I am not saying that dispersion
was necessarily increased in this instance, but just
floating the idea, for discussion, that it might have been,
and suggesting some possibilities for the ways that
dispersion might have been increased.

- Surmise.. is that a fancy way of saying "use common
- sense"?

It's a way of saying "draw the tentative conclusion that".

-- We can only make an assumption, but it is probably
-- a fair one.
-
- Probably a very very VERY fair one.
-
-- No, and I never suggested it.
-
- Was implied.

If you inferred it, I didn't mean to imply it, and I
am sorry if my language gave the impression that it
was implied.


-- "I noted that dispersion and ROF pull in different
-- directions in terms of the bullet density at the
-- target area."
-
- Note you didn't say, there is a *CHANCE* that with
- increased ROF there may be a decrease in bullet
- density.

There I was noting that dispersion tends to decrease
bullet density, and ROF (all other things being equal)
tends to increase it. In that statement above (in
isolation). I was noting two factors
that are contributions to bullet density, nothing more.
I don't understand how on earth you could have interpreted
it in the way you say.

- Fine, just wanted to point out to you that it came
- off that way..

Sorry.

- A perfect example is what you said
- above, i.e. the dif directions statement.

Ok, that one to me seems clear and unambiguous, and
I am genuinely confused as to your misinterpretation
of that one!

- No, it is just my way of pointing out how silly it
- is to think it was BAD, in that someone, be it the
- mechanic at convergence testing, or the pilot after
- a sortie seeing his tracers all over the place... it
- would have been apart and talked about by someone.

Good point. As a counterpoint to that, at what point
is the extra dispersion, in the heat of combat, visible,
and how much means a noticeable reduction in bullet
density at the target? (Assuming the same ROF).
If could be that the additional dispersion isn't visible to the human eye, especially under stressful combat
conditions.

This might be further
masked by there being more tracers airborne at any one
time. I don't suppose to know the answer to it, but it
is possible that if the bullet (and thus tracer) density
at the centre of the bullet stream was increased, then
a small increase in outliers might not be noticed.

The human brain is able to discriminate the smallest
changes in some things, yet can be fooled easily in others
in the area of perception. I suppose that being able
to distinguish some things is more evolutionary useful
and a more highly developed skill.

I think you'd need to talk to a psychologist to determine
if people can distinguish between a number of trials with
small variance (low ROF, low dispersion) and a higher
number of trials with slightly higher variation (high
ROF, slightly higher dispersion?).

Who knows. Maybe there is something out there in
the psychology literature?

This doesn't mean that I am saying that there _is_
increased dispersion, just that if pilots didn't perceive
it doesn't necessarily mean it wasn't present.


-- There could be increased vibration, unequal or
-- unintended pressure variations, etc. All manner of
-- possibilities.
-
- Agreed, could be, but, it appears there wasn't, in
- that had there been they would have removed the mod.

Well we don't have enough information to be definitive
about that, so we can't claim that as a fact. We can
presume that any increase in dispersion wasn't so large
that the modification wasn't still useful, but we can't
presume that it didn't increase dispersion without
finding some additional evidence. If we had a .50 and
some motors in theory we could test it, but that's
not likely to be an option!

- In that I don't see how you can have IMPROVED bullet
- density and INCREASED dispersion at the same time?

It's perfectly possible!

Ok.. back to a dice analogy. You have 60 dice. If you
throw a 4 or above, you put then box A, if not
you put them in box B. At the end you'd expect to have
about 30 dice in box A, more or less. You then repeat
the experiment, but with 100 dice, only now you only
put them in box A if you throw a 5 or above. You should
have 33 dice in box A. If the number of dice in box A
represents bullets on target (or a measure of bullet
density) then bullet density has gone up. The chance
of a dice ending up in box A has gone down, though.
You just have more dice.

As to the perception in real time, I suppose it would
be like throwing up all the dice and somehow having
special 'box A seeking dice' and seeing if you can
really see (without peeking in the box) as they fall
how many are going into which box.

-- It depends on the action of the .50 in detail, and
-- how being pushed a bit outside its manufacturing
-- tolerances might affect it. Or the .50 might be able
-- to cope with a higher rate of fire without adverse
-- effects.
-
- I think I should point this out again, the electric
- motors were designed for use with the .50 MG!

Yes, I understand that, but also the .50 was originally
designed for a lower rate of fire, and there may be
details of that design which made them behave in
a less than ideal ballistic or mechanical manner at that
higher rate of fire.

The requirements for guns on bombers in terms of
the way they present their fire to their targets is
different to fighters.

- on a windshield wiper or a dish washer.. it was
- designed to be used on/with the .50 MG.

If you had a car rated at 100mph at a certain octane
fuel, and then decided to drive around at 120mph after
filling up with higher octane fuel, would you expect
the engine life to be higher or lower? The fuel was
designed for engines, it is an engine, but you may
be running the engine beyond its design specs. You
can't assume that it will behave as well.

- Ah, ok, now your semi qualifying your def of how you
- can have improved bullet density and increased
- dispersion at the same time. Problem is I don't buy
- it!

See the dice analogy above. It's not too complex
a concept.

- Disagree, in that it there is a 3rd case, no
- IMPROVEMENT in bullet density at all and no INCREASE
- in dispersion. Keep in mind the mod was NOT to
- address density or dispersion, it was to address the
- jamming problem.

If there was an increase in ROF and no increase in
dispersion, then it is not possible for there to be
anything else other than an improvement in bullet
density without some of the bullets spontaneously
turning into dewdrops en route or something.

- The higher ROF was just a
- bi-product of the jam fix mod.

And if dispersion was not increased than a side effect
would be increased bullet density.

I would presume that the original design of the motors
was to increase ROF, though, If the original intention
of the motors on bombers was also just to prevent jams
then it would seem an unnecessary strain on the guns,
and on ammunition supplies to also increase ROF.

If you were designing purely to prevent jams, then
feeding at a faster rate would seem a bad way to go
about it, as you'd be putting more strain on the gun's
mechanical components and ammunition feed.

what did the motors actually speed up? They must
have been linked to the action of the guns in some
way, to have speeded up the ROF, I would imagine.
Was part of the logic that having the motors cycle the
action that a misfire would mean that the action would
still be cycled and the unfired round ejected? There
seem to have been two mechanisms for P51B jams - one
an ammunition feed jam, the other a firing solenoid
malfunction. Driving the cycling of the action would
allow some solenoid misfired without stopping the
following firings.

- YOUR MISSING THE MAIN POINT!! It was designed for
- the fifty cal!!!

No, haven't missed that at all.

- DID I JUST HEAR YOU SAY THAT WITH ENOUGH GUNS (i.e.
- MORE GUNS) AN ENEMY FIGHTER WAS LIKELY TO BE HIT?

Yes.


- FUNNY... THERE WAS A GUY SAYING SOMETHING LIKE THAT
- WITH REGARDS TO 8x0.50 vs 6x AND 4x... WHO WAS THAT
- BRILLIANT GUY AND WHERE DID I READ THAT?

Ah, that's because you are misunderstanding Bayesian
statistics.

With a fighter, the guns are all aimed by a single act,
so all the guns form an interdepdendent system, with
probability of hit of all guns (apart from ballistic
concerns) being down to the targeting at that instant.
I.e P(hit) is really P(hit|aim) in Bayesian speak - the
probability of a hit is really the probability of a hit
given that the aim is correct. This is true for all of the guns.

With a bomber you have a number of indepdendently targeted
weapons. In this instance P(hit) is really P(hit left waist gun | aim left waist gun). You have a number of independent
aiming actions. In this instance the total probability of
at least one hit climbs faster with the number of guns
deployed than with a fighter. However, conversely, the
average number of hits climbs _less_ quickly than with
increasing number of guns on a fighter.

With a lot of statistical analysis on large trials
you tend to reduce P(hit|aim is correct) to P(hit | any
aim at all, correct or not) which is what I did in my
analyses. The reason for this is that there are so many
aiming scenarios, that the trials are too rich in
detail if you had to list every aiming scenario too.
The thing is to not lump together too many very different
sets of aiming scenarios together and lose the detail
in trying to get some gross, managable overall idea of
the behaviour. Mind you, politicians quite often
do lump things together (data pooling) if it helps make
their point. I hope I managed to avoid data pooling in
what I was doing, though. It certainly wasn't my intention
to data pool.

- For bombers yes, never said it wasn't, my only point
- there was to point out that the electric motor was
- designed to work with the .50 cal, thus all your
- worries about it damaging the gun were null and
- void.

It might cause more wear, it might cause more dispersion.
Neither of those, for a bomber gun, might have been
that important, or not so important as just filling the
sky with lead.

-- In a fighter mount dispersion is rather lower.
-
- If any at all.

There is definitely dispersion. I am on the trail of a
gunnery manual from the RAF( I was hoping the HMSO
might have a copy - they used to issue various
WW2 manuals, but their web site is an alien experience!
Very confusing) which suggests that the dispersion for
a fighter (.303s) at 400 yards is a circle of about 20ft
diameter. That's definitely dispersion, although that
will be dispersion from all sources.

XyZspineZyX
08-03-2003, 10:03 PM
MiloMorai wrote:
- I have never seen so much manure being spread as
- that which is coming from you.
- You should do something about that diarreha.

Really? What about the time your mom said you look good in those close she dresses you up in? /i/smilies/16x16_smiley-wink.gif

- The 85gal tank, just filling in some details, you
- left out.

I didnt, you just didnt understand them when I said them, too busy going on about how the tank in the center is not on the centerline.

- OBW, the 190 and 109 used their centreline 300 l.
- tank first and then switched to the fuselage fuel
- tanks, err, for you, that is the fuselage
- horizontal/plan centreline fuel tank.

Hey, send me your home address and Ill send you a gold star!



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
08-03-2003, 11:04 PM
Personaly I Like the F4 & G6AS alot

never realy messed with the f2 much or g6

of corse the dora & A9 are high on the list as well /i/smilies/16x16_smiley-happy.gif

<center><FONT COLOR="white">ӚFJ-M œ R D ˜ ӡ[/i]</font>

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<center><FONT COLOR="black">
I am He who lives, and was dead
and behold
I am alive forevermore.
I am the Alpha and the Omega
the Begining and the End.[/i]</font>