Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Dimlee]

This is what my Me163 il2fb flight model works well at also, its slightly dissappointing to climb at such a shallow angle when you have seen film of Komets climbing vertical.

I'd like to see such films. With the vertical climb. 

[taly01]

I should have said ..incredibly steep climb from takeoff......   Komet is one of the most fun planes in game, along with Ki27,. Making a quick mission with 4v4 Me163 v Ki27 is hilarious to watch.

[taly01]

I got to read more Komet history with speed record tests by Heini Dittmar, its interesting how the Me163A with only 750kgT reached 1,002kph, yet the Me163B with 1700kgT reached only a bit more 1,130kph.  Assuming he used the full 1700kg thrust, is all that extra thrust since Me163A 1700-750=950kg absorbed by turbulence/Mach compressibility?

[SAS~Storebror]

is all that extra thrust since Me163A 1700-750=950kg absorbed by turbulence/Mach compressibility?

Exactly.
The Komet speed is Mach limited. Wings are both too thick and their profile isn't suitable for transsonic speed. Additionally, all control surface become immediately ineffective once mach compressibility kicks (they all reside in the wake of the Mach cone).
Many of the anecdotal records of allegedly "transsonic" flights in wartime are wrong.
Either they cited it wrong, or the wrapped a story around the less astonishing truth, or it's simple propaganda.
For instance, the 1003kph flight of the Me 163A in 1941 is usually quoted as "high above Peenemünde".
"High above" this wouldn't work. There's a reason for all world speed records of the subsonic jet era to have been set right on the deck in some sort of deserts.

Our Me 163, after this rework, will reach 1000kph in a dive only. It will almost reach 1000kph in level flight and it will not be able to go supersonic, not even if you dive down vertically from 20km altitude.


Mike

[KingTiger503]

I Found Something in my book about the Komet,,

Check this out if you zoom in




Best Regards KT503

[SAS~Storebror]

Thanks KT, but as with so many books, this is wrong in so many ways.
The length of the Komet is 5.92m and the height is 2.80m. Source: D.(Luft) T.2163 B "Me 163 B Flugzeug-Handbuch" Teil 0 "Allgemeine Angaben".
The maximum speed is on the deck and depends more on environmental temperature than anything else. The speed at 10km altitude could be anything and it's of no interest whatsoever.
The "initial climb" equals the speed. 5000m/min would be 300kph. Seriously, no one keeps you from going almost 1000kph on the deck, pull up and "initially" climb three times that fast.
The "service ceiling" is misleading for a Me 163. It can climb (especially zoom climb) much higher. Thing about "service ceiling" is that it denotes the sustainable max. altitude. Taking the very limited flight time of the Me 163 into account, by the strict definition of it, the "service ceiling" for the Me 163 is ground level.

Fuel consumption: We know that the specific fuel consumption of the HWK 109-509 A-1 is roughly 5.3 lbs / 1000lb sec. at sea level, full throttle. Source: "Analysis and evaluation of german attainments and research in the liquid rocket engine field" vol. vii "thrust control" - ADA800132, feb. 1952.
1700kp thrust equals 3750lbf, so we get a fuel consumption of 19.875 lb/s at full throttle on the deck.

With 2018kg of fuel this results in 224 seconds full throttle time max, that's 3 minutes and 44 seconds.
I know this looks disappointing and it contradicts reports from e.g. Wolfgang Späte ("4-5 Minuten Vollschub") or many other sources which like to state 7.5 minutes burn time, but hey: You can't betray physics.
If a Me 163 ever made a powered flight for more than 4 minutes, then it's just for the simple reason that they've throttled back, which they had to do anyway.

"2 1/2 min from top of climb or 8 min in total" means the climb would take 5 1/2 minutes, which it doesn't. The climb takes 2 1/2 minutes if you do it right.


Mike

[taly01]

The Me163A level speed with the little 750kgT rocket is already at the safe limit of the airframe, the Mach limit is only around that of a P-51 and less than Spitfire!

Given Mach 0.82 is the limit of Me163
at 1000m is 996kph
9000m is 898kph
This supports I read 900kph was the do not exceed speed for Komet combat pilots.

The Me163B 1700kgT rocket was insanely overpowered for its Beetle airframe, the Me163B is a plane that tried to kill its pilot in many ways.