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View Full Version : Bf-109 series extraordinary controls at high airspeeds



XyZspineZyX
09-05-2003, 10:09 AM
If I'm not mistaken..the Bf-109 family's controls (pitch, roll, yaw ) became increasingly heavy at higher airspeeds until about 500km/h and beyond they were virtually immovable. In IL2 FB v. 1.1 ...i've noticed that the 109s have excellent controllablity at very very high airspeeds. Am I wrong?
Oleg please check this out for me ..
Thanks

<center>
<img src=http://68.67.55.154:109/jerry/109popout2.jpg>

XyZspineZyX
09-05-2003, 10:09 AM
If I'm not mistaken..the Bf-109 family's controls (pitch, roll, yaw ) became increasingly heavy at higher airspeeds until about 500km/h and beyond they were virtually immovable. In IL2 FB v. 1.1 ...i've noticed that the 109s have excellent controllablity at very very high airspeeds. Am I wrong?
Oleg please check this out for me ..
Thanks

<center>
<img src=http://68.67.55.154:109/jerry/109popout2.jpg>

XyZspineZyX
09-05-2003, 10:33 AM
Remains heavy but still responsive at 500km/h~600km/h ranges in FB v1.1F.

Over 600km/h TAS, it really gets heavy. Over 650km/h TAS, in FB, I can't get my Bf109 into an accelerated stall, because the elevator authority is so limited that I cannot pull it into an AOA high enough.

Please please, try it out at various speeds and test it carefully, before you post these sort of claims.


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Message Edited on 09/05/0306:36PM by kweassa

XyZspineZyX
09-05-2003, 08:28 PM
For the 109Es, maybe its somewhat correct. But those hardly ever faced such airspeeds in combat.

The 109 series from "F" onwards is a different matter. It was only the elevator that was heavy, and not by as much as you would think based on Eric Brown. It was possible to make heavy Gs in order of 5-6 G up to speeds of 500-550kph, ie. maximum manouvering combat speeds. Beyond that it got heavier, but I have an extreme test where they put a 109F into a 70-80 degree dive, reached about 850 kph TAS before starting to pull it out, which they managed to do about 1000m after the pullout was initiated... IMHO, pretty aduquate for 95% of the cases, of course not the best.. but it should be kept in mind that pulling more than 6-7Gs was risking breaking the airframe, esp. at high speed on most planes.

Unlike elevator, ailerons and rudder forces were actually very light on 109F and G, and even lighter on 109K with Flettner-tab assitence on them. 109G was reported to have 80-90 degree rate of roll at 450 kph, with only 20lbs stickforce, half of that of the maximum. This is very light, by all standards.

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'Only a dead Indianer is a good Indianer!'

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XyZspineZyX
09-05-2003, 08:58 PM
Ironman69 wrote:
- If I'm not mistaken..the Bf-109 family's controls
- (pitch, roll, yaw ) became increasingly heavy at
- higher airspeeds until about 500km/h and beyond they
- were virtually immovable. In IL2 FB v. 1.1 ...i've
- noticed that the 109s have excellent controllablity
- at very very high airspeeds. Am I wrong?
- Oleg please check this out for me ..
-
- Thanks

You _are_ mistaken, as I had already pointed out to you once. 2 others have now as well. /i/smilies/16x16_smiley-wink.gif

This is the myth that refuses to die. lol /i/smilies/16x16_smiley-happy.gif

XyZspineZyX
09-06-2003, 09:57 AM
Maybe you get annoyed by AI planes? They are such dirty cheaters it really blows off me hat.. http://ubbxforums.ubi.com/infopop/emoticons/icon_mad.gif

Try following a rather tame 109 driven by your leader down to 100m alt at 720 km/h and zoom with thim that 12 G loop back up.....

This is an aspect I hate about FB. In a p-47 a dive to chase that bogey down to the deck is done cause you know youre controls are a good deal more responsive ... *shakes head*


muffinstomp

XyZspineZyX
09-06-2003, 11:29 AM
yeah if found the high speed control of late war 109 very bad between 500and600km/h he is quite heavy approching the Tb3 FM hehe then he is simply immobile

for a K4 who go at 720km/h at 6000-7000m i found this very strange have they built a very powerful plane but just for fly straight and do nothing exept be killed because uncontrable at those speed.

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NN_EnigmuS.
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XyZspineZyX
09-06-2003, 01:02 PM
Ironman69 wrote:
- If I'm not mistaken..the Bf-109 family's controls
- (pitch, roll, yaw ) became increasingly heavy at
- higher airspeeds until about 500km/h and beyond they
- were virtually immovable. In IL2 FB v. 1.1 ...i've
- noticed that the 109s have excellent controllablity
- at very very high airspeeds. Am I wrong?

In V1.1 the high speed control of 109s was overmodelled. After the betas it is downgraded, but whether the extent is accurate can´t say.



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XyZspineZyX
09-06-2003, 03:23 PM
jurinko wrote:
-
- Ironman69 wrote:
-- If I'm not mistaken..the Bf-109 family's controls
-- (pitch, roll, yaw ) became increasingly heavy at
-- higher airspeeds until about 500km/h and beyond they
-- were virtually immovable. In IL2 FB v. 1.1 ...i've
-- noticed that the 109s have excellent controllablity
-- at very very high airspeeds. Am I wrong?
-
- In V1.1 the high speed control of 109s was
- overmodelled. After the betas it is downgraded, but
- whether the extent is accurate can´t say.


There was no difference in elevator forces between Bf-109F&later and late war allied planes. If you notice something then it is not modelled correctly.


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XyZspineZyX
09-06-2003, 04:12 PM
NN_EnigmuS wrote:
-
- for a K4 who go at 720km/h at 6000-7000m i found
- this very strange have they built a very powerful
- plane but just for fly straight and do nothing exept
- be killed because uncontrable at those speed.
-

It`s not always logical, but there are some factors that explain it, why the heavy controls at high speed remained:

-it keeps the pilot from breaking his plane at high speeds bz exceeding allowed G-loads for airframe,

-or entering a high-G stall (airflow separates more easily when pulling it heavily at high speeds because of greater acceleration. The Me 109 had moderately high wingloading, and the slats could only make up for it if the G load increased gradually, and not suddenly (they needed some time to open and restore airflow).

-or blacking out himself and loosing his conciousness, loosing control over plane. It happens to me sometimes in Il-2, and it`s much worser than heavy controls alone when I am in a dive... /i/smilies/16x16_smiley-sad.gif

It`s also less important becasue of the nature of fight, because high true speeds happen only at high altitudes in fights, where you have little IAS and lift at the same time. So again, if you were allowed to make big elevator movements, you could stall the plane more easily. At low or medium altitudes, it`s not a problem because you travel at lower speeds as well, the plane cant go very fast.

And, regardless of control forces, there`s the human factor: if a pilot has light controls, and pulls a lot of G, he will feel the loads, and could pull less force while under G anyway. He would limit himself in any case...


Also keep in mind that the 109 was not the only plane with heavy elevator forces, the Mustang had practically the same elevator forces. Still, not many are aware of this..

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'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
09-06-2003, 04:53 PM
Mark Hanna says that over 300 mph the ailerons get very heavy:

The roll rate is very good and very positive below about 250 mph. This is particularly true of the Charles Church's Collection clipped wing aircraft. Our round tipped aeroplane is slightly less nice to feel. With the speed further back the roll rate remains good, particularly with a bit of help from the rudder. Above 250 mph however the roll starts to heavy up and up to 300 or so is very similar to a P-51. After that it's all getting pretty solid and you need two hands on the stick for any meaningfull roll rates.

Regards,

SkyChimp

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XyZspineZyX
09-06-2003, 05:19 PM
SkyChimp wrote:
- Mark Hanna says that over 300 mph the ailerons get
- very heavy:
-
- The roll rate is very good and very positive below
- about 250 mph. This is particularly true of the
- Charles Church's Collection clipped wing aircraft.
- Our round tipped aeroplane is slightly less nice to
- feel. With the speed further back the roll rate
- remains good, particularly with a bit of help from
- the rudder. Above 250 mph however the roll starts to
- heavy up and up to 300 or so is very similar to a
- P-51. After that it's all getting pretty solid and
- you need two hands on the stick for any meaningfull
- roll rates.


This is not at all in disagreement with other pilots. However, "very heavy", compared to what? In absolute terms maybe.

Say if we compare the heaviness of the 109s ailerons, we find that, compared to other fighters, P-47, P-51, Spitfire, they are very light.

From what I read, at 260-270 mph, the P-51 surely needed 50 lbs stickforce to achieve maximum deflection.

The P-47C, with 50lbs stickforce, could achieve maximum aileron deflection up to 230 mph IAS if I am not mistaken (looking at the NACA chart and what you posted).

The Spitfire MkVA, in NACA test, could only fully deflect ailerons up to 110mph IAS with 30lbs stickforce, and up to only 130mph with 40 lbs stickforce. The NACA roll chart says 50lbs for full deflection at 200mph.

That already means the use of two hands. With one hand, a pilot can only exert 18 to 22 lbs SIDEWAYS force (See "Dynamics of Flight - Stability and Control" graph).
For more force to use, he needs two hands (except for the potential future govenor of California maybe).

Me 109G pilot had very light ailerons, and could full deflect them with only 20 lbs stickforce :

"A full stick roll through 360 degrees at 460kph takes 4 to 4.5 seconds without using rudder, and needs a force of around 20 lbf. One interesting characteristic is that rolls at lower speeds entered at less than 1g, such as a roll-off-the-top or half Cuban, have a markedly lower roll rate to the right than to the left. Therefore, I always roll left in such manoeuvres.

- Dave Southwood."

http://109lair.hobbyvista.com/articles/airframes/black6/bk6_flight.htm


Notice how well Mark Hanna`s description agrees with this when put together.

A pilot can make about 20 lbs force with one hand sideways.

Dave Southwood tells that he needed about 20lbs for full deflection at 300mph.

Then Mark Hanna says that above 300mph, two hands are required ! Of course, it gets heavier, past the 20lbs force what Southwood said, and which is the maximum with only one hand.


BTW, thanks `Chimp, I was unaware up to now, that relative to other planes, the 109 had THAT light ailerons !



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'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

Message Edited on 09/06/0306:22PM by Vo101_Isegrim

XyZspineZyX
09-06-2003, 09:31 PM
Is it true that the 109k did not suffer from or not as much from a heavy elevator at higher speeds?