Nose Heavy Lancs

**kdriver** · February 27th, 2012, 05:30

Is there a fix or can some kind person correct the nose down attitude on Buddha13's conversion of Dave Garwood's Lancaster? The AI aircraft pile up on take off and landing as well as flying with a nose down attitude.

By the way, I'm getting good frame rates for bombing attacks on the Tirpitz with 16 Lancs and heavy flak over the fjords of northern Norway.

**Oglivie** · February 27th, 2012, 17:49

Originally Posted by kdriver

Is there a fix or can some kind person correct the nose down attitude on Buddha13's conversion of Dave Garwood's Lancaster? The AI aircraft pile up on take off and landing as well as flying with a nose down attitude.

By the way, I'm getting good frame rates for bombing attacks on the Tirpitz with 16 Lancs and heavy flak over the fjords of northern Norway.

Initially looking at the Air file it appears that the Horizontal Stab incidence is a bit high and this will push the nose down as speed increases...try it at zero. Another possible problem is the Wing Center. If there still is issues try reducing the wing center to 20. The stab incidence, and possibly with the wing center change, should fix the problem.

The Wing Incidence may or may not be okay with these changes. If it flies with too much nose down (at zero vertical speed - level flight) the wing Incidence could be reduced a degree or two also.

Cheers,
O

**bearcat241** · February 28th, 2012, 02:52

KD, you have the guys taking off from the grass in your pic, which sort of explains some things at least in my own mind. Do they behave like this on hard runways as well? I've seen this happen before on a few occasions with heavy models where my AI flight spawned off runway instead of center runway. As they began roll out or touchdown at landing they go nose down. This happened in my cases because the actual runway position in the associated scenery *.bgls and the airbase.dat conflicted with the position in the mission file. Corrections may be in order there.

BTW Oglivie, your air file pic from Buddha13's conversion contains the exact same data as the stock 1% AvH 1GB_LancasterMk1. We all know how careful those guys were about this kind of detail. Apparently Buddha decided that the 1% flight dynamics was the safest bet for this conversion, which follows a long-standing and common pattern in our community. Kinda makes me doubt that the stock FDE is the source of the problem, but hey, sh*t happens, right?

The 1% FDE packages are generally good bets for both player and AI. But every so often you might get strange AI behaviors due to the sophistication of the 1% designs, which sometimes causes the CFS2 AI engine to stumble a bit.

**bearcat241** · February 28th, 2012, 04:06

Ok Kdriver, i re-read your post again and noticed that you mentioned that the kites also fly nose-down, in addition to their strange ground behavior. Sorry i missed that before. As Oglivie suggested, your air file and/or aircraft.cfg will need some complex mods to eliminate that completely. I'm guessing here that your cfg shows empty_weight_CG_position= -0.08, 0, 0 // (feet) longitudinal, lateral, vertical distance from specified datum. This -0.08 longitudinal CoG may need to be offset backwards a bit more to keep the nose and tail on the same horizontal plane in flight. This will also help the ground behavior.

**kdriver** · February 28th, 2012, 15:46

Thanks very much Oglivie and Bearcat. I'll try each of your suggestions separately, as well as placing the aircraft on a wide concrete runway. Here's the cfg file entry: empty_weight_CG_position= 0.000, 0.000, 0.000. The Lancasters are carrying Tallboy bombs, so I'll also try having no payload to see if this makes a difference.

**kdriver** · March 1st, 2012, 17:12

I tested the mission with the Garwood/Buddha Lancaster and frame rates were good.

Changes to the air file, the runway surface, and the payload made no difference to the landing/takeoff attitude.

I now have this entry in the cfg file: empty_weight_CG_position= -1.00, 0, 0. This fixes the takeoff and partially fixes the landings - the aircraft have their noses down but don't generally blow up on touch down. The aircraft is tail heavy in flight.

Thanks for your help chaps. :ernae:

**bearcat241** · March 1st, 2012, 18:28

That's progress my man...keep at it. As long you get the AI to behave, you can always trim that heavy tail. What you really need is an FDE makeover. Maybe swap another Lancaster-based flight model into the equation, with a few tweaks to carryover engine locations, scrape points, contact points and other misc.

**Oglivie** · March 1st, 2012, 18:41

I had some time to tinker a little. No easy answer tweaking the current 1% Air file, so I tried a VB_Lancaster Air and the AI were good. It needs tweaking either way, but will be easier with the VB or similar Air file. Where the exact tweaking needs to be done for the 1% file escapes me at the present time.