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Working on BMW -- prevent crash -- bmw760li.zip -- made it fly


il88pp

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In another thread I replied, but also asked a question.

I got an answer from napamule2.

To not muddle up the thread, I decided to split it off as a separate thread, here goes!

 

Originally posted by user: 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!

 

Thanks for all the pointers! I'm doing a flight now, no trial and error possible for quite a few hours.

I will try your advice. I'll start with the 'static_cg_height=xxx' and go from there.

If I remember correctly I tried changing compression and it got bouncy after a small change, but I will look at it again.

I don't know if I understand balance correctly. It does not lean over in corners when driving. And it corners real good while flying. So I think balance is ok, yes??

 

What is the actual center of model (not CoG)? Where is this defined?

 

You said "But there is more (.air file values, engine power, etc)". Do you mean this in relation to making it fly? Or was that in relation to crashing as well?

It does fly fine. A little nose up, true, but good enough for me.

 

The model is the: bmw760li.zip

But no need to dig out your FDE's. I would rather dig my own way out of this one. It's sort of a leisure craft anyway. Not one I fly every day, especially not in this cold season.:)

 

I have a lot of eating to do as well though, and some other stuff, so it may be a while untill I get down to it in earnest.

 

Merry -X- Mas!

il88pp.

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Ok, be that way. No one is going to force you to accept any mods. Or argue about it (if this was you aim). Best to SHOW you how it's SUPPOSED to work. This is a PT Cruiser I did 3 years ago. I have better video of BMW (extreme) but need to edit so as to embed. I'll be BAAACK.

Chuck B

 

Here is the BMW as a 'beast' (extreme performance FDEs-just for fun). I can't enbed (or edit) so the link will take you to YouTube to watch. Vehicle FDEs is all I do 24/7 for 10 yrs+. Enjoy. Link: https://youtu.be/c7XDuSTUopA

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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My aim was not to argue:).

 

No, I's just I want to learn. Not only fix this one's crashing, but also be able to fix other ones later. That kind of thing. I'd rather learn how to make my own FDE then copy one efrom you.

 

You taught me how to make the BMW fly, and that worked out very well. Handles great. Takes off at 65 knots. Thanks.

I don't use it to drive much, or to drive high speed. I usually fly to some nice spot off airport, park, and camp out for a while. Picknick, coffee, and on my way again.

Your help is much appreciated. I just have a few too many chestnuts in the fire at the moment. I will keep an eye on the thread and get there when I get there.

 

 

A question about the Video. Was that filmed with crash detection on?

I heard a grinding noise in the sound at times but I don't know if that was a crash with crash detection off, or a "scrape" with crash detection on.

Thanks.

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Like they say: 'Limitations May Apply'. I ALWAYS turn off crash detection. The FDEs will help but due to 'bumps' (caused by vertex) you WILL crash due to stress, etc. That's the nature of the 'beast'. You MIGHT drive 100 miles thru mountains and not crash (at 25 kts - hehe). But at speeds higher than 60 kts you are not going to make it with crash detection ON. Or one day you will and the next time you won't. Why worry about it. Just turn off crash detection and enjoy your vehicles in all 'scenarios'.

 

The 'smoke' and possibly 'sparks' you saw in video is due to vehicle 'hunching down' on tires when I pull back on joy stick when it is going at high speed. I forgot to turn off 'sparks' in (Effects). And the 'noise' is cnt pts noise (0,2,3,4,9, etc) which I forgot to change to '4' (water splash - which only 'sounds' when on water so not when on asphalt when it hits a bump (there are many 'hidden' - which will crash you).

 

My latest video (here) shows Airbike with gear down and even on land it just 'scrapes' against/over 'bumps' and keeps on going and not crash. On land or water (water does have 'sand bars' and 'sudden' elevation changes ('wall') that are not smooth). That ability to slam into things and not crash is due to cnt pts, of course. (Mums the word bird..hehe). I can drive into a 45 degree 'bump' on road at 200 kts and not bounce in the air. Keeps on trucking - doesn't even slow down. It's ALL cnt pts my friend. Asta la vista Baby... . (Get your own - hehe).

Chuck B

Edit: Moderators: you can lock this thread now - we are 'done' with this... (hehe)

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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Hooo Hooo Hold on a second:D Two more quick questions.

 

Even with crash detect off sometimes a crash is so hard that the engine quits.

Would it help to use a .air from a high wing aircraft and use that as basis?

Or are engine positions in the model.

 

And I think I asked before, but just to be safe. Would trying a tricycle gear help?

Or is that a waste of time?

It has 4 wheels now. But that feels weird.

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Oh oh. It's supposed to be 'Ho Ho Ho'. Where did the other 'Ho' go? I don't know. :-)

 

Ok, the crash making engine quit is due to 'stress...'. So you also have to uncheck 'Stress causes crash'. OK? OK! (I was going to say (kidding) that is was due to you smashing up the propeller - ha). Was that too simple? Knowledge is power.

 

And 3 wheels DON'T work right. Believe me. I tried. I have found that only 4 wheels will lend themselfs for vehicle wheels (ie: always on the ground as opposed to just in 'contact' with ground when landing). The question is very legit. I have had long arguments with modelers of vehicles that insisted 3 wheels would be better. So I said, ok go ahead and send me the cnt pts so I can test them. It's been 9 years and haven't heard back from any of them. One also said 'I don't need your FDEs. I am going to learn how to do it myself'. I never heard back from him either.

 

So by now you are thinking I am all 'smug' and full of self pride and arrogance about vehicles FDEs (AND cnt pts). Not so. It's just that this has been my FOCUS for the last 10 years. Lots of hard work. Lots of trial n error. Lots of 'start over' days. Lost my good FDEs for vehicles in a 2012 hard drive crash (bad MBR). The files are still there but it costs $400 to retrieve the data by pro lab. The FDEs I have now I made starting in 2012. To top it off I had a full blown stroke in 2012. I keep working - damn the torpedoes - full speed ahead. You only live once. Might as well make the best of it.

Chuck B

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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I knew you have worked on this for years. And it's much appreciated. That's why I was trying to tap some of your knowledge.:):D

Ok, 4 wheels it is then. I'll try getting my head around that. Recieved and understood. Thanks.

 

I said high wing aircraft.

I should have said high wing with engine on wing - aircraft. Would borrowing an air file from one of those help. (props being higher up?).

Or is 'props highere up' a .mdl thing?

 

Engine stress... good workaround. Should have though of that myself. Thank ou.

 

Sorry to hear about that crash. Maybe worth a try connecting that disk to a linux (live) system. "systemrescuecd" for example.

 

Hooo Hooo Hoooo, Meeeeeeeeeerry Christmas!!

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Um, pardon my intrusion, but isn't

[GeneralEngineData]
engine_type = 0
Engine.0 = 7.5, 0, 0.036
fuel_flow_scalar = .73
min_throttle_limit = 0

the third line (Engine.0 = 7.5, 0, 0.036) of this section what you're looking for?

That's out of the _Spartan aircraft.cfg file, but, except for gliders, all planes haves one. It's read the same way lights and so on are: Longitudinal measure, Latitudinal, Vertical, in that order. Measured from the usual reference point.

From what I understand, that defines where the thrust from the engine occurs, so on jets, it's the aft end, on props, the front.

I don't mean to intrude. I apologize for interfering. Carry on.

Pat☺

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Had a thought...then there was the smell of something burning, and sparks, and then a big fire, and then the lights went out! I guess I better not do that again!

Sgt, USMC, 10 years proud service, Inactive reserve now :D

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Hi Pat, thank you! Your brainwaves always much appreciated!:rolleyes::D I hadn't even thought of looking in that section. And I assumed the aircraft.cfg would probably not affect it anyway. Some variables in there are "just for show" I hear.

It may well have an effect, but I somehow doubt that position info prevents the props from breaking...

 

I didn't test the change you pointed out though.

I realised that I was prbably thinking along the wrong track anyway. Must have been all that nogg!

The engine is probably placced just right already.

I realised the engine usually stalls when I drive down a steep slope nose first. Moves that would make any aircraft cringe, no matter where the engine is positioned.

In his video's Chuck is driving on relatively flat surfaces. Roads, airports. I drive it off road and off airport most of the time.

It doesn't stall that often. Only during extreme moves. Andf there's always "Aircraft Reload" to fix it.

 

I think the best path for me is Chucks workaround, to switch "detect engine damage" off, and take it from there.

Even if positioning the engine higher (using aircraft.cfg) helps, it would probably affect the handling, and especially the flying.

I may try it someday, and if moving the engine up helps I will let you know. But it's on the back burner. And testing these kind of small incremental changes is usually a long drawn out affair anyway.

 

Thanks guys, off now for some more celebrations.:) Wanna keep this feeling going a little longer.:D

il.

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No sweat!

Have a great time, and enjoy the Nogg! I love the stuff, although I use a good Brourbon rather than rum in it. Well, I used to anyway...

For the stalling maybe you need an aerobatic carb set in the aircraft.cfg file? Just a thought. They happen so rarely...

Pat☺

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Had a thought...then there was the smell of something burning, and sparks, and then a big fire, and then the lights went out! I guess I better not do that again!

Sgt, USMC, 10 years proud service, Inactive reserve now :D

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No. Aerobatic carb only helps if you plan on going up-side-down. Vehicles are not supposed to do that (ha). So that leaves around 24 other things to 'fix'.

 

The idle FRICTION setting in (engine) section will cause problem due to xyz. Here is default value: idle_rpm_friction_scalar=1.0 //Scalar on idle RPM friction .

 

Change it to: idle_rpm_friction_scalar= 0.6 //Scalar on idle RPM friction .

That should cure the engine dies problem on crash or bump. Actually you should of noticed that the engines die anytime it's on idle, so this might not be it. If it is, then there is only 23 other things to fix. You thought is was easy, eh?

Chuck B

i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D:). FS9 and FSX Acceleration (locked at 30 FPS).
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Engine does not die on idle just parked a while. I must have done something right.

You and some others helped me with the bmw worked on this in a thread 3-4 mnths ago. That thread was about using aired.)

 

I put 0.6 in, will try a test flight later.

 

Difficult...

It's like that climbing saying. "Every sheer cliff look daunting at first. It's when you get close up with it that you start seeing the weaknesses in the rockface you can use. A crack to wedge your foot in, a good handhold..."

I can only judge how difficult it was at the end of the journey. And even then that wouldn't mean a thing to anyone else.

Glad to have you as a traveling companion.:D

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I was about to throw in the towel.

 

I had raised wheels a bit. And "raised static_cg_height=" a little more then wheels

and changed to: idle_rpm_friction_scalar=0.6

I also moved the engine as Pat suggested. I placed it between th efront and rear wheels. (so driving down a slope wouldn't foul the prop).

And I moved the engine up from -3 to 3.

I managed to land 1t 18000ft in the andes, without stalling the engine. But I stil got a engine stall, even while driving over not even all that uneven terrain.

 

My head's not really in the game. I rather do some relaxing flights then keep reloading and tinkering.

So was gojng to say; "I'd like to leave it here for now. I hope we can pick it up again at some later date."

 

Then I made one last attempt. i did what I had planned in the firs phase. Added floats.

I added two floats at the front wheel positions, just a bit further out to the side.

And two floats exactly at the rear wheel positions.

I also disabled all scrapes that were in there.

Now no more crashes I think. Engine did not stall even after some very rough high speed driving.

(Btw, I was surprised to see the BMW topped out at 20.000 ft. I crossed a couple of high peaks on the way to machu Picchu.:) )

 

Thanks you two. Goal achieved. I have no idea which of the changes helped most. I may have a look at gear compression ration later.

Much later! first I'll cruise into the new year. No more messy tinkering on planes for a bit.

 

Thanks much!:D

il88pp.

 

edit: Oops, just noticed that engine vertical changed from -3 to +3 means the plane doesn't easily lift off or climb. (Trim at the stop.) Fine when returned to -3 again.

Glad I know now, can be useful later.

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