Flip Flop Aircraft Engine Starting?

[rhodges]

With some aircraft, when the engine is started, the aircraft goes completely crazy flip flopping and wandering all over creation. It almost seems that the prop stays still and the aircraft rotates which may not actually be the case. Bill Lyons J3 Cub and the Commercial Level Simulations Arrow II would be examples. This is not a constant problem. Sometimes the aircraft will startup normally, but I have never been able to isolate the cause, or solution. Has anyone else seen this happen and have any idea what the correction might be?

 

Thanks:

RTH

[mrzippy]

I have seen it even with the engines not running! The plane wants to hop and bounce around. On one aircraft I changed the contact points and made it steady.

[rhodges]

Thanks for the reply mrzippy

 

I know what you are talking about. Normally corrupt contact points will result in a similar situation any time the aircraft is taken out of the slew mode, and the aircraft will go crazy. The aircraft in question are sitting properly on the ground and quite stable with the exception of when the engine is started. I am not sure I have ever seen it happen with a multi-engine aircraft. The simple solution is to select the aircraft with the engines already running and there is no problem, but that does lack a bit of realism

 

Thanks again:

RTH

[il88pp]

I have a car in I use in fsx. Well, I say car, butit's not anymore really. It still looks and feels like a car, but I made it so it now flies as well.

 

Anywho, this car shows some the following behaviour.

If I switch it off., use slew, pause, unpause, and then try to start it with the starter in the VC, it takes off almost vertically. If you then are not very quick to get it back using slew, it totally spins out of control and either keeps climbing or crashes somewhere off-airport.

 

I still can't put my finger on what causes this. The problem could be caused by, in this aircraft, the toggle fuel valve command, the starter, the slew, the pausing, possibly even reloading aircraft or scenery while in slew, or even changing aircraft settings (crash detection off/on) while paused or simply during flight/taxi.

Another idea,

I often "crash" with this "plane".

I land it off-airport. I prefer uphill landings, in the rough, and tose aren't really what the gear was madde for. I actually adjusted the gear contact points, because with the wheel position it had the wheels hovered above he ground. Unfortunately this change means it now sometimes even crashes while driving. (it looks much better though)

Anywho,

I usually fly with crash detection off. And crash it often. You do recognise this, the plane makes a little jump when it crashes.

I have a feeling that only after a flight and (crash) landing, when I turn the engine off, and then on again later, the vertical takeoffs and Spinouts happen.

 

I manage to take control of it usually by quickly pressing "y" to enter slew mode, then "F1" to touch down, then "y" to exit slew, and then "control E" to start the engine.

 

So try to start, especially after a crash. - I hope that helps.

 

From what you guys are saying I should adjust my contact points I suppose... Would moving them sideways help?? because I don't want to move them down. I want the wheels to visibly touch the green surface.

 

Edit: Hey! Maybe i'll try adding some floats just above the wheels, (or scrapes?!):confused:. That may stop it and cause some sparks as well.:)

[napamule2]

When you first load your DEFAULT flight (C-172, I hope, and not 3rd party or payware aircraft) move your joystick and be ready to push F1 (throttle cut) as the throttle will go to 100%. This behaviour is due to setting of throttle sensitivity and null (spike). The setting should be 95% sensitivity and 5% null. Fix? Never found one. Deal with it.

 

Every airplane I have seen comes out with 'static_cg_height=xxx' wrong. If main gear height is '-4.010' the 'static_cg_height' s/b '4.210'. It will load '0.200' 'in the air' and then 'drop' and due to compression be 'right' and not sail off or spin. No use asking the 1000 or so modelers to change to this 'standard'. They don't 'take orders' or 'DO' requests.

 

The cnt points for a vehicle (or car, or truck, or tank) that rolls on the ground have to be changed as the flying 'object' cnt pts won't 'make it'. Then it will not crash on making a turn at 40 kts, or when it hits a 'bump' (vertex), yet the wheels will be on the ground (ie: not hovering). Every model is different. The modeler, when he designs the gear, actually 'gives' the gear it's 'properties' (ie: compression). You have to observe, then trial-n-error, to properly adjust the cnt pts. Then there is the fuel load (position of tanks) and engine(s) (poistion) which effects the 'balance' and, of course, the actual center of model (not CoG). But there is more (air file values, engine power, etc). Having the model of 'car' I can make beneficial changes to behaviour in about an hour or so. I might even have a set of cnt pts/cfg/air for that model as I 'own' almost evey FREEWARE vehicle out there. Let me know (PM me your email addy). I KNOW I can help.

Chuck B

Edit: So do I have to emphasize that you NEVER make a 3rd party aircraft your 'default' flight and ALWAYS make the C-172 your 'default' flight. There is a proven benefit in making the C-172 the 'default' flight. It sets things up so FSX can function properly. No if or buts about THAT. Got it? OK!

[evm]

With some aircraft, when the engine is started, the aircraft goes completely crazy flip flopping and wandering all over creation. It almost seems that the prop stays still and the aircraft rotates which may not actually be the case. Bill Lyons J3 Cub and the Commercial Level Simulations Arrow II would be examples. This is not a constant problem. Sometimes the aircraft will startup normally, but I have never been able to isolate the cause, or solution. Has anyone else seen this happen and have any idea what the correction might be?

 

Thanks:

RTH

 

Sometimes I get this when the aircraft is a certain amount overweight. I stumbled upon that by accident, using an external app that adds weight. If I overload the Alabeo Pawnee Brave by roughly 300 lb, she starts jumping when the engine is running and leaps and bounds when she takes off. Same thing with the default Cub. Maybe take a look at weights and balances, size of the fuel tanks etc.. As a test you could remove 50% fuel before startup, see if it still jumps.

[il88pp]

Napamule2, Thanks, I'm starting a new thread with a reply. I don't want to hijack this thread.

( https://www.flightsim.com/vbfs/showthread.php?295587-Working-on-BMW-prevent-crash-bmw760li-zip-made-it-fly )

[ScatterbrainKid]

Just a thought but maybe the 5 realism sliders have got something to do with the flip-flopping, especially the Torque factor so it might be worthwhile juggling them to see if it helps-

 

http://i53.photobucket.com/albums/g64/PoorOldSpike/sub2/FSX-Airc-Realism_zpsbdxr8kic.jpg~original

[jpatt1000]

I first had this proplem with Virtavia's B-29. I've now had the He-111 and the new AJ2 Savage do it as well. It seems to happen when you crank the starter with the fuel shut off. I got around it by first starting the plane with SHIFT+E Then shutting the engines down individually. That way I know for sure the state of the fuel controls and the I can start them individually from the VC or using "engine 1 start" etc. from keystrokes set up in the options menu. No clue why it's just been these three.