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View Full Version : Please look into the R4M rockets

XyZspineZyX
07-18-2003, 09:13 PM
I have been noticing the large performance drop off with the R4M rockets attached to the Me 262. I had assumed that the two SC 250s would be more of a hinderance.

MiloMorai, in another thread sited that:
2 SC250 bomb > -75kph(8700rpm), -65kph(8400rpm)

I flew some tests at 4000 m and 8400 rpm. The speed drop off with the 2 SC 250s was right on. Then I flew the same test with the R4M rockets. The drop off was HUGE! At 4000 m and 8400 rpm, a clean 262 will top out at about 925 km/h. With the R4M rockets attached, it can't pass 675 km/h. Now, with the two SC 250s it got up to about 850. Think about this for a second or two.

2 X SC 250 : Top speed 850 km/h
24 X R4M : Top speed 675 km/h

The SC 250 each weigh 250 kg, and each R4M rocket weighs 4 kg. 24X4=96 250X2=500. Anyone else noticing something VERY wrong? With the 500 kg payload it can reach 850 km/h, but with the 96 kg payload it reaches 675 km/h !!??!!

Now, after I launched all the rockets, it could get up to 900 km/h. So that's the effect from the launch rails, only 25 km/h difference. That means that from 675 km/h to 900 km/h, the sole reason is the rockets. Simply ridiculous for 96 kg. Also don't forget that the R4M set up is MUCH more aerodynamic than lugging two bombs under the nose. Please fix the 262's performance with the R4M rockets.

(Edit) Note: the normal max speed is 870 km/h. I was only using half fuel for these tests, that's why it reached 925 km/h clean.

Message Edited on 07/18/0301:41PM by Stecher_3.-JG51

XyZspineZyX
07-18-2003, 09:13 PM
I have been noticing the large performance drop off with the R4M rockets attached to the Me 262. I had assumed that the two SC 250s would be more of a hinderance.

MiloMorai, in another thread sited that:
2 SC250 bomb > -75kph(8700rpm), -65kph(8400rpm)

I flew some tests at 4000 m and 8400 rpm. The speed drop off with the 2 SC 250s was right on. Then I flew the same test with the R4M rockets. The drop off was HUGE! At 4000 m and 8400 rpm, a clean 262 will top out at about 925 km/h. With the R4M rockets attached, it can't pass 675 km/h. Now, with the two SC 250s it got up to about 850. Think about this for a second or two.

2 X SC 250 : Top speed 850 km/h
24 X R4M : Top speed 675 km/h

The SC 250 each weigh 250 kg, and each R4M rocket weighs 4 kg. 24X4=96 250X2=500. Anyone else noticing something VERY wrong? With the 500 kg payload it can reach 850 km/h, but with the 96 kg payload it reaches 675 km/h !!??!!

Now, after I launched all the rockets, it could get up to 900 km/h. So that's the effect from the launch rails, only 25 km/h difference. That means that from 675 km/h to 900 km/h, the sole reason is the rockets. Simply ridiculous for 96 kg. Also don't forget that the R4M set up is MUCH more aerodynamic than lugging two bombs under the nose. Please fix the 262's performance with the R4M rockets.

(Edit) Note: the normal max speed is 870 km/h. I was only using half fuel for these tests, that's why it reached 925 km/h clean.

Message Edited on 07/18/0301:41PM by Stecher_3.-JG51

XyZspineZyX
07-19-2003, 01:41 AM
A little bump for a worthy cause.

http://members.optusnet.com.au/~athosd/mypic3.jpg

XyZspineZyX
07-19-2003, 02:55 AM
From what I see, the rockets effect a wide area of the wing's underside. The boms are put on pylons so its not to effect the boundry later. The rocket pod is a big block that interupts a lot of the aerodynamics going under the wing. I think it has more to do with aerodynamics then weight for max speed. But I also dont think you should get knocked down 300KPH for the rockets.

Gib

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XyZspineZyX
07-19-2003, 06:10 AM
Stecher_3

before you get to carried away with speed here are some numbers for average speed of the Me262. They are taken off a small size Messerschmitt graph so will not be to the exact kph.

3250m > 715kph
4000m > 780kph
5000m > 800kph
6000m > 840kph
7000m > 870kph
8000m > 890kph

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

XyZspineZyX
07-19-2003, 02:32 PM
Rockets have a quite dramatic effect on aerodynamics, that's why they stopped putting 16 rockets on IL2s after the first model. And i think that effect is causing the extra loss in max speed, but i agree that the speed drop seems exagerared though (but i'm no expert on this). Is there no hostorical source with data on Me262 performance with R4M rockets?

Soundtech AKA 249th_Jag

XyZspineZyX
07-19-2003, 07:59 PM
The IL-2 carried rockets of 82 mm and 132 mm. The R4Ms are only 55 mm. I'm sure that they are going to make the 262 slower, but only a bit. If you want to argue that the interuption of airflow under the wing is the problem, that's fine. But remember, after all the rockets are fired, there are still the launch rails. And they only cause a slow down of 25 km/h. The rockets alone can't possibly slow it down another 225 km/h. Think about it logically. The pilots of the 262 were mainly the best of the best, and very particular about things. The R4M were not uncommon, and out of all the pilot quotes of the 262, I haven't seen one mentioning that there was a significant reduction in speed when carrying them. In all likelyhood, that would have been a big complaint if true. Let's look at it this way. In FB, carrying the R4M takes an aircraft capable of speeds near Mach 1, and turns it into an aircraft that is clearly slower than both the P-51D and the P-47D. If this is accurate, do you think the Luftwaffe would have used them? Of course not.

XyZspineZyX
07-20-2003, 01:56 PM
I agree.. and russian planes don't loose any speed when they are carrying rockets.. but FW-190 and Me-262 surely do...

VVS rockets should also be fixxed.. At the moment carrying 6 rockets with Yak1 does not slow her speed at all.. or manouvarability..

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XyZspineZyX
07-21-2003, 11:11 AM
as example..the loose of speed for an FW190F8 with 16 panzerblitz rockets was 30km/h with rockets, and 15km/h without rockest.

wastel

XyZspineZyX
07-21-2003, 11:47 AM
In addition to wastel's comment, the A-8 could do 550kph @ 2km, clean, but could only manage 515kph @ 2km with a SC500. At 3km, the speeds were 540kph and 510kph respectively.

'Clean' is with no ETC rack.

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

Message Edited on 07/21/0306:50AM by MiloMorai

XyZspineZyX
07-21-2003, 12:50 PM
BOOOOOOOMMMPH <-- like bump but louder

XyZspineZyX
07-21-2003, 03:46 PM
Stecher_3.-JG51 wrote:
- The IL-2 carried rockets of 82 mm and 132 mm. The
- R4Ms are only 55 mm.

I don't think it has much to do with the size of the
rocket, so much that the location and mounting disrupts
a large proportion of the underside of the wings. In addition
the drag is likely to increase as the speed increases.

The amount of wing disrupted by 16 rockets on an early IL2
is probably not vastly dissimilar from that being disrupted
by 24 R4Ms. At IL2 speeds, the amount of extra drag is
probably similar to that on the 16 rocket mount on the IL2.

However, the original test done was at maximum speed.

Perhaps a fairer comparasion of the drag between 16 RS-82
on an IL2 and 24 R4M on an Me262 is to find the maximum
speeds (with and without rockets) on the IL2, then fly
the Me262 clean with the throttle set such that it
attains about the same speed, and then try with the same
throttle setting, but with R4M and determine what the steady
speed is with the rockets.

XyZspineZyX
07-21-2003, 05:05 PM
Bathtub IL~2 much slower than sleek Me~262. Junk rocket drag much more effect on Me~262 at high speed. Also, Me~262 much more advanced design, and less tolerant of junk hanging under wing.

What Noob compares Me~262 with IL~2??

XyZspineZyX
07-21-2003, 05:27 PM
funny thing is, that the rocket rigs for the
mig and lagg series doesn' t slow down the plane.
with rockets, yes..there is drag..but the racks with
no rockets produce no drag...
..lol..balancing?

wastel

XyZspineZyX
07-21-2003, 07:34 PM
Pilots reported that R4M had very little effect on flight characteristics.

The numbers wastel provided for the FW seems very reasonable.

Anyway, this has already been reported several times and I guess it will be fixed with the patch.

XyZspineZyX
07-21-2003, 10:23 PM
wastel wrote:
- funny thing is, that the rocket rigs for the
- mig and lagg series doesn' t slow down the plane.
- with rockets, yes..there is drag..but the racks with
- no rockets produce no drag...
- ..lol..balancing?
-

The mountings for the RS-82 are comparatively
narrow, but project through the boundary layer.
Basically they are small pylons.

The R4M mountings are wide, flat plates attached
to the wings carrying a number of rockets, sitting
right in the boundary layer. Such a mounting does
make is easy to attach a launching facility for a
large number of rockets quickly, but see my last
paragraph.

The R4M and RS82 are pretty different mountings,
with different drag profiles, I would imagine. So
what is seen in FB may not be that inaccurate. Or the
lack of drag for unloaded RS-82 pylons may be an
oversight, and/or that for the R4M overdone.

These days aircraft tend to have pylon-mounted weaponry
on the wings, rather than the ordnance attached very
close to the wings. I expect there are several reasons
for this, but I wouldn't doubt that some of it is
aerodynamic. For large numbers of small rockets (the
equivalent of the R4M concept) they tend to be mounted
in pods on the end of pylons, rather than spread out
over the wing.