Variable Vmcg?

[tarmac12]

I was going through a interview prep book and came across this question. It gives an answer but I still don't get it. If sounds as if Vmcg is a variable depending on weight. I always thought it was one speed only. Here is the question and I hope someone can shed some light on it for me.


If VMCG is limiting, how would you increase aircraft weight?

By reducing take-off thrust. This would allow a lower value of VMCG and so the V1 could be reduced, resulting in a greater take-off weight for the same take-off distance.

Thanks

[Tankengine]

That is Question and Answer!:ok:

[john_tullamarine]

You might run a query in Tech Log. This topic has been the subject of numerous discussions. One of the sideline advantages of derate takeoff.

[AerocatS2A]

It's not variable depending on weight, it is dependent on thrust. If you have lower thrust there is less asymmetric thrust if you lose an engine so vmcg is lower. This may allow for a lower V1 if the V1 was limited by vmcg. This may allow a greater takeoff weight if the limit was stopping distance on the runway.

[pilotchute]

Thanks Aerocat. Always simple once it's explained to you.

Cheers