Take off problems

[Pat Pattle]

Here's an odd one.

The Wellington I in BoB will not take off from certain airfields (RAF Honnington in the test), just sits there stuck to the runway.

I copied over one of the MAW Wellies and on the same airfield it takes off. The fm's etc are all identical, it's the same model re-skinned.


The BoB Wellie did take off from Duxford, the only difference I can see between it and Honnington are the object files. Duxford has a "concrete" runway in the file, Honningtons is "grass".

However when I change Honnington to "concrete" it still won't budge.

Any one any ideas please? I have a feeling this has been discussed before many moons ago.

Cheers,

Clive

 

[MajorMagee]

Payload differences?

 

[NachtPiloten]

Takeoff

There are two issues at play here. The modeled hesitance the ground is exerting onto the wheels and the limitation of the propeller curves in the airfile. Well actually they work in unison. The problem here is similar to the one when you have a seaplane. The resistance the water places is initially too high for the propeller thrust CFS models using either aired or airwrench parameters. You really need to manually revise the propeller tables to have the thrust much greater at low engine/airplane speed. Second, grassy/dirt fields are modeled have higher roll resistance than paved runways.

This is why in many cases higher than expected throttle is needed to initiate takeoff, we usually do not spend enough time in the tables to compensate for this programming characteristic. So to fix this the tables should be revised to provide more initial thrust for a given prop angle and throttle position. The downside it that this a tedious process and usually does not present in most cases; mostly limited to seaplanes ( I have spent many an hour getting this right for the PBY and Sunderland - thanks to Greg Pierson for showing me the way!!!). I have noticed this before on the Wellington but rocking the plane often got her to roll (idle to full throttle repeatedly).

The major is correct, load will make a difference so for now reduce fuel as in most cases we never need maximum fuel load to fly in CFS3 unless you are going England to Italy and back.

If you want to learn how to do this let me know and I will be happy to share.

shchaslyvoho Rizdva -

 

[Pat Pattle]

Thanks for the replies Andy and Ted, I wondered if it was fm or payload related but I don't think it is.

In QC, same aircraft, same payload, same everything it will not take off from RAF Honington but it will take off from RAF Scampton. The 2 airfields share the same facility and object files so it can't be the fm.
I've even tried swapping the contents of facility files over between airfields but still no go.

It's almost as if it's geographic but I can't see any obvious difference in the global layer or qclocation files either.

Gremlins?

 

[Bravo/4]

Have you tried WEP Clive?

 

[gecko]

As Ted says, fixing the propeller tables will solve it, but it can be a real pain. In air dat, the first propeller table has the thrust parameters. If you increase the values in the second column, starting on the second row (leave the first column and first row alone at all costs) this will increase the thrust produced by the propeller when the aircraft is at zero airspeed.

The geographical aspect of this is odd though.