DCS: Me 262 Discussion (Development on hold currently)

Any new pictures? Updates? Nada?

Flame-out, not fire.

I don't know much about the subject, but this book seems to have a different opinion?

https://books.google.pl/books?id=RAbFQiX1F9AC&pg=PA9&lpg=PA9&dq=me262+engine+fire&source=bl&ots=kXiCYRm9UG&sig=bBWgQ0Hp7uEAZSsRvBmzTClnCms&hl=pl&sa=X&ved=0ahUKEwjFreKUy7XKAhVkwHIKHVS7BaIQ6AEITTAF#v=onepage&q=me262%20engine%20fire&f=false

Page 11:

"We had to be very careful with the throttles and advance them very, very slowly, or there was a risk of fire"

And there seem to be more flame-ups with some of the 262's. I don't know, maybe it was a different engine... but just wanted to point that out :P

Could it be that the chance of engine fire was present at the start up process, which was using ordinary aviation gas before switching to diesel J-2 jet fuel?

Maybe the avgas was more sensitive to sudden injections.

In any case, the engine startup process definitely appears to be a unique experience with the 262. :)

Could it be that the chance of engine fire was present at the start up process, which was using ordinary aviation gas before switching to diesel J-2 jet fuel?

 

Maybe the avgas was more sensitive to sudden injections.

 

In any case, the engine startup process definitely appears to be a unique experience with the 262. :)

Yes indeed and there is even more about the flame problem that it was even a fire hazard after switched to J2 fuel:

"The engines were started using Reidel starter unit. The turbines were run up to 1800rpm and C3 fuel was used to light up the Jumo. The throttle was advanced very very slowly untill at 3000rpm, you could switch to J2 fuel. Again one had to advance the throttles very slowly to 6000rpm and as one increased to 8000rpm the throttles could be used a little faster. Both Nowotny and Gunther Wegman suffered turbine fires because they advanced the throttles too rapidly."

The thing that I do not understand though is how can the same thing (advancing the throttle too fast) lead to putting out a fire and fire, two opposite things at the same time...

I guess engine fire could occur for a number of reasons at any time and any engine, and perhaps they misunderstood the cause.

The thing that I do not understand though is how can the same thing (advancing the throttle too fast) lead to putting out a fire and fire, two opposite things at the same time...

 

I guess engine fire could occur for a number of reasons at any time and any engine, and perhaps they misunderstood the cause.

Could it be that these are two seperate events that occured after another? Flameouts as I understand it is choking the fire in the combustion chamber by either not providing enough air through the intake (example sudden sharp turns or obstruction) or enriching the mixture too rapidly. After the choke, would the engine then flood with fuel (basically going outside of the combustion chamber) which could ignite on a seperate source and therefore create an uncontrollable runaway fire?

Just been reading some of this is very interesting

Apologies if its earlier in the thread, but the Jumo's were axial, although the ultimate way to go, I believe it was a mistake to tread that path, I think it was the path pursued by Ohain. They would have been better sticking to the well understood centrifugal types which were used as supercharger units in reciprocating engines for a fairly long time.

The axial engine even now walks a tightrope and has very narrow surge margin.

Speculation but advancing the throttles too fast could easily do 2 things

1) Cause a large step in the fuel flow before the engine had rotated to high enough RPMs to increase the air mass flow to keep the temperature under control. This would exceed the material limits in the hot section and would lead to nozzle and turbine damage which would reduce the propulsion developed. It could easily cause overtemperature and a fire.

2)The increased mass from the fuel could also lead to a larger pressure differential across the compressor leading to surge condition which is easily capable of blowing out the flame.

So depending on a lot of other variables it could well result in either condition

This is pure speculation with a sprinkling of knowledge of gas turbine engines and their performance

The first one is not so dangerous, generally, as the step of fuel flow rising the temperature then overcomes the combustion margin - flame-out.

The second reason that leads more probably to the flame -out is so called temeperature throttling - increased gas temperature leads to decreasing the admittance of turbine stator nozzles (or turbine itself) and air mass flow decreasing, that causes, in its turn, further temperature rising, etc, up to compressor stall, catastrophic air mass flow decreasing and flame-out... :)

 

 

By the way, L-39 has for its engine a manual mode - true hardcore manual, even without rpm governor, so, anyone can try.

I'll take your word for it YoYo, from my experiences with GTs they all behave very differently depending on the configuration of the 3 main sections.

I can certainly see the first, but a little unclear on the second. Help me here to understand.

Are you saying the increase in temperature causes a decrease in mass flow (makes sense) as the load stays the same the speed drops, and the condition is self feeding leading to flame out? I would think that could also do a lot of damage to hot gas part components too.

Or have I failed miserably to grasp the concept :book: :doh:

There was only one fire reason some sources mentioned - on the ground. Flame-out, a lot of fuel thrown to the ground then new ignition - fire.

Makes sense, thanks for the clarification Yoyo! :)

I hadn't realized ED was planning to actually do a 262 until I saw this thread. Nice!

I'll be taking this bird online and killing F-15s with it.

Are we getting the version with the more idiot-proof throttle? I can't say I relish the prospect of constantly killing my engines because of my laughably imprecise (one-inch throw) throttle slider. : (

just make it a option in the menu to have it simplified...

Ew, no deal! I'd much rather struggle with my shitty throttle slider than turn on an arcade aid. : /

Legitimate question by Echo, will we get the 004B Jumos with throttle governor? Will the aircraft feature the EZ42 as does the Dora?

Ew, no deal! I'd much rather struggle with my shitty throttle slider than turn on an arcade aid. : /

A dedicated throttle isnt that expensive, and it would free up your current slider for some other useful functions :thumbup:

@ED: Please give us some early Jumo's.... :-(

Legitimate question by Echo, will we get the 004B Jumos with throttle governor? Will the aircraft feature the EZ42 as does the Dora?

Hopefully we get it with the more reliable B-4 engines with the throttle governor, anything else would be abit weird.

Ideally we get the option to have it on or not though, that way you could simulate the B-2 engines without it as well.

As for the EZ-42, well that would be nice, again though the option to choose would be ideal :)

As for the EZ-42, well that would be nice, again though the option to choose would be ideal :)

Though the EZ 42 was fitted to the Me 262, IMHO considering the ballistics of the MK 108 it would make as much sense as fitting a sniper scope to a a sawed-off barrel shotgun. :lol:

You are being bit harsh on the MK108s Kurfürst! ; ) Sure they have a comparatively arked ballistic trajectory (probably close to a naval gun :D ) , but in terms of precision/spread are actually a bit better than the higher velocity MG151/20s. Anyway, I wouldnt like to be on the receiving end of 4x MK108 nose canons with or without an EZ42. :surrender:

PS: Please include R4M rockets!

From what I remember it was mainly the 109 pilots who complained about the Mk108 ballistics. Considering the much higher speed and airframe ruggedness of the 262 they could actually be somewhat more effective.

R4M would be nice indeed even though we got no B-17s to shoot at (yet).

From what I remember it was mainly the 109 pilots who complained about the Mk108 ballistics. Considering the much higher speed and airframe ruggedness of the 262 they could actually be somewhat more effective.

 

R4M would be nice indeed even though we got no B-17s to shoot at (yet).

I don't think we will see a 262 before the Normandy Map including units anyway.

From what I remember it was mainly the 109 pilots who complained about the Mk108 ballistics. Considering the much higher speed and airframe ruggedness of the 262 they could actually be somewhat more effective.

It should als be possible to adjust the guns in term of horizontal and vertical convergence in the 262. Now that isnt possible with a prop mounted gun, so shells will quickly fall below the nose at high ark trajectories. The MK108 is a really a much better fit in 262 than in the 109 as you said.

Ew, no deal! I'd much rather struggle with my shitty throttle slider than turn on an arcade aid. : /

but.. you want throttle governor to be standard just because you can't enable an assist? how is it any different?