[BUG] Dora accelerating with stopped engine

[Aginor]

Hey guys!

I noticed something really really weird.

I have attached a track. Please forgive me my really bad flying, I haven't flown the Dora in ages and I had some problems with my controls.

 

Anyway, here's what happened:

I took off after a ramp start, then I was fidgeting around with my cooling, and then I killed my engine. Well, not THAT unusual until that point.

But then something weird happened: As I was looking whether I could glide back to Batumi I noticed my plane accelerated. Pretty quickly actually.

Finally I crashed because I was travelling at the speed of sound.

 

I haven't tried to reproduce it yet, but I will do that soon.

 

EDIT: Yep, I can reproduce it. It is pretty hilarious actually. I just augured in at over 800 knots.

EDIT: After further testing it seems I can't reproduce it every time. I did it twice but then the next retries I couldn't...

Dora_speeding.trk

Edited August 14, 2015 by Aginor

[Aginor]

Anyone who can reproduce that as well?

[Anatoli-Kagari9]

I will try it tonight and report back!

[Anatoli-Kagari9]

Hehehh... Unbelievable!

 

I did try your track, and as speed was increasing past 350 mph I took control, and from there continued until the ailerons, elevator and other surfaces started to detach.

 

We really have a problem here - FDM, wrong RAM calculation ?

Edited August 20, 2015 by jcomm

[Aginor]

Yeah, in my second try I tried climbing, which is jet-like.

Most limitations of the piston engine still apply, like that it doesn't work once you are too high up. Then the plane started descending, gaining LOADS of speed. Finally I blacked out, my wings ripped off, but the plane kept accelerating, eventually reaching about 800 knots in the dive, shortly before crashing.

Most impressive!

 

I am still not sure what causes it though. I _think_ it happens at exactly the point where the engine stutters and dies, except it doesn't in those cases because it skips the stuttering and goes straight to a complete stop. Every time it did that the speed bug happened.

 

I am not an expert for flight models, but I am a coder. To me it looks like there may be an undefined state in a state machine for the engine system.

[Anatoli-Kagari9]

I begin to think it is something related to the ramjet / exhaust thrust with some problem with it's code.

 

There's an hint on it's implementation and effects in this thread.

 

Could you please try with ISA weather too because it's cold weather /dense (atmosphere) in your SITU file, and this can impact the ram calculations, I believe .... ?

Edited August 21, 2015 by jcomm

[Aginor]

Ok, I'll try that. Can't promise it will happen in the next few days though.