Differents engine power for a same speed in close formation

[diditopgun]

Hi !

 

A strange behavior happened tonight in multiplayer with a friend.

To stay in close formation at the same speed with the same external payload we had very different engine parameters:

 

Me: RPM 80%, fuel flow 54 kg/min, remaining fuel 2,4t

Him: RPM 90%, fuel flow 72 kg/min, remaining fuel 2,3t

 

He had to apply far more power than me to stay in formation with a bit lighter plane than me (he had less fuel)...... WTF ??? :shocking:

 

I don't know if it's related to M2000 or DCS but... so strange !

[PiedDroit]

You should still have the track in your Saved Games\DCS\Tracks\Multiplayer, can you post it here?

 

I'd be interested to see the AoA's and speeds.

As you can fly at the same speed either with low AoA or higher AoA which puts you in a different regime (*) (with more drag) that requires more power.

I don't know if that could apply here.

 

(*) I think the correct translation is "backside of the power curve", correct if I'm wrong - in french it's "second régime de vol".

[diditopgun]

Speed ~700km/h and same AOA ~5° for both players (confirmed on tacview ACMI):

 

[PiedDroit]

Speed ~700km/h and same AOA ~5° for both players (confirmed on tacview ACMI):

One of them is smoking. Bad carburetor tuning if you ask me. Give that mixer screw one eight of a turn I'd say.

Joking aside, it's obviously not what I was thinking about, I hope someone else can reproduce. I'll check that next time I have time to fly with a buddy.

[xaoslaad]

Were you hosting? I'd bet anything clients lag. My buddy always falls _way_ behind me even when we start rolling down the runway together.

 

I could just be more agressive in vaporizing digital fuel. I suspect a little of Column A, a litle of Column B, not that I have proof of either...

Edited May 23, 2016 by xaoslaad

[diditopgun]

Yes I was hosting.

[bkthunder]

I noticed the same on the VA server with some other guys, but then I realised that some people are flying the Open Beta, and some the Release version of DCS. I'm not sure but it could be that.In the OB the Mirage was patched and the engine was tuned to solve a bug that gave too much power at altitude.

[jojo]

I'd be interested to see the AoA's and speeds.

As you can fly at the same speed either with low AoA or higher AoA which puts you in a different regime (*) (with more drag) that requires more power.

I don't know if that could apply here.

 

(*) I think the correct translation is "backside of the power curve", correct if I'm wrong - in french it's "second régime de vol".

 

I would say it's unlikely in close formation flying in level flight.

A given thrust and AoA give you a given speed, and reciprocally if you have the same weight.

 

It would need confirmation but I think that with landing gear retracted (SLATS out) the FBW prevent from flying in "second régime"

[diditopgun]

I noticed the same on the VA server with some other guys, but then I realised that some people are flying the Open Beta, and some the Release version of DCS. I'm not sure but it could be that.In the OB the Mirage was patched and the engine was tuned to solve a bug that gave too much power at altitude.

 

We were all in open beta version so it's not linked to it.

 

When you notice this on VA server it was with the Mirage or other planes ?

[Azrayen]

I could have had a similar issue with Su-27. Never thought of investigating it re: host vs client, but could be...

[PiedDroit]

I would say it's unlikely in close formation flying in level flight.

A given thrust and AoA give you a given speed, and reciprocally if you have the same weight.

 

It would need confirmation but I think that with landing gear retracted (SLATS out) the FBW prevent from flying in "second régime"

 

Yes you're right, OP gave some parameters (AoA and speeds) that clearly rule out this possibility.

Probably a client /host issue as indicated by others.

P. S. i think it's possible to go in second regime even with FBW as there's no autothrottle and FBW won't make the A/C pitch down to regain speed. but that's another debate :D

Edited May 23, 2016 by PiedDroit

[bkthunder]

We were all in open beta version so it's not linked to it.

 

When you notice this on VA server it was with the Mirage or other planes ?

 

It was with another Mirage, but I have no idea about his fuel load. I supposed he was heavier 'cause he needed A/B while I could keep up with MIL.