reported Engine overspeed bug

[GUMAR]

It seems to me, that developers didn't notice my pos in "correct as is" topic, so here is new one.

 

  

On 1/20/2021 at 12:19 AM, GUMAR said:

Made a simple test.

Manually set 2800-2900 RPM. MP well above 40". 50 seconds --> Master bearing damage. While "maximum permissible diving RPM" is 3060 from P-47s manual.

Conclusion.

Bearing damage occurs whenever you exceed 2800 RPM regardless of manifold pressure.

 

P.S. As a background, I did numerous dive tests before to find operational limits for P-47.  

P-47_bearing_dmg.trk 39.53 kB · 6 downloads

 

  

On 1/20/2021 at 1:08 AM, grafspee said:

Agree, 3000rpm 52" main bearing damaged after 8 second.

 

[felixx75]

On 2/16/2021 at 5:07 PM, GUMAR said:

"maximum permissible diving RPM" is 3060 from P-47s manual

Wich manual? The manual, which comes with the module speaks about a max. normal rpm of 2750. There is also the red marking. 

[grafspee]

24 minutes ago, felixx75 said:

Wich manual? The manual, which comes with the module speaks about a max. normal rpm of 2750. There is also the red marking. 

Every single one about P-47. 

Same case as in P-51.

3000rpm is max rpm set by governor, but maximum permissible rpm is 3250, again red marking at 3000rpm.

[felixx75]

1 hour ago, grafspee said:

Every single one about P-47.

I think, the sim refers to it's own manual. And there I can't find anything about 30x0 rpm (but I may be wrong).
Since i only know the game manual, i would be curious to know more. Do you have a link to another manual?

 

edit: (but that's not really correct, because its about the "N"-model -> different, more powerful engine, new turbocharger)

Edited March 10, 2021 by felixx75

[grafspee]

It was linked couple times already.

Doesn't say how much long engine can operate at this rpm, but in game even below 3000 makes your engine dead after couple of seconds.

Edited March 10, 2021 by grafspee

[felixx75]

Since WEP (64'' @ 2750) or even TO Power (52'' @2700 rpm) is limited to 5 minutes (military to 15 minutes), "seconds" seems very short, but not to far. The engine MAY be overspeeded for up to XX seconds (while diving), that does not mean, that every single engine will reach this without damage. Some engines will have survived this, others not. So you have one of the engines, wich dies at these parameters, and tbh these few seconds won't make a huge difference in our simulation.
So just stick to the parameters, the DCS manual gives you and the engine won't die after 8 seconds...

Edited March 17, 2021 by felixx75

[grafspee]

Limits are set that all engine will survive it. Those are operational limits that's it. If manual says 3060 rpm is max, it is just that way.

Going in to any detail is just pointless.

And power limits are quite different thing. 52" 2700 is limited to 15 min.

It is not total limit so when you let your engine cool off you can engage another 15 min

Staying at 2700 rpm but with reduced MP for example 35" you can fly much much longer then 15min. 

What is the issue here that engine is going puff even before 3000rpm.

Lowre rpm allow for more economic flight.

Edited March 10, 2021 by grafspee

[grafspee]

Just remember that those engines are projected for 300h-500h, so operational limits are set accordingly. Probably you should get away with 1 hour of military power in that thing. 

Don't think that those time limits are set at the edged. RPM/MP are quite close limits as always you want to have as much power from engine as possible.

So if you exceed 3060rpm in dive you should expect something to happen. If you push engine couple minutes longer then limit nothing really happens maybe it loses 20-40 hours of life time.

When in flight i overspeed prop rpm, i cant do much, only is to pull out of the dive.

I always refer to real manuals if it comes to DCS warbirds.

Edited March 10, 2021 by grafspee

[NineLine]

Hey all, this is reported, thanks!

[GUMAR]

On 3/18/2021 at 1:39 AM, NineLine said:

Hey all, this is reported, thanks!

Great, thank you!