F-111E/F and EF111A (JY)

[delbydoo]

Thank you John for your time - I found the same as Giorgio, taxi's and takes off fine, bounces during landing but that I can live with; as others have said before, it is a cracking model and now has it's place in the sim. It must be extemely niggling to come across this sort of thing after you've spent many hours making it, so again thanks for the time you have put in.
Unfortunately .air file tweaking is beyond my remit (I've never been able to get AirEd to read a file anyway) so I'll leave it to someone else to sort that last bit of bounce out.

[MIKE JG]

The first priority is to get the model to sit properly on the ground while is is sitting still. I noticed that the model on my setup does not sit level on the ground either static or during taxi when it's not moving.

That should be the starting point and then go from there.

I don't know if you modeled gear compression into the landing gear but if so, that complicates things a bit and takes a little more work.

It's a brilliant model, with some work I'm sure you guys can tame it.

[delbydoo]

It's a brilliant model, with some work I'm sure you guys can tame it.

To quote Galaxy Quest: "Never give up, never surrender"

[Stewart Pearson]

Okay dokey,

Experiment part deux.

I altered the contact points as suggested on the previous page and this did eliminate the bouncing during taxi and on the take off run.

However I did still have a bounce or three just at the point of rotation from the runway.

Been swapping out values etc for the last 2 hours and have (on my set up) managed to iron that last bit out.

I'm using the following values;

[contact_points]

point.0=1, 12.77, 0.00, -4.5, 1181.1, 0, 0.89, 46.8, 0.6349, 2.5, 0.9100, 10.0, 10.0, 0, 260.0, 260.0
point.1=1, -9.88, -4.31, -4.0, 1574.8, 1, 1.70, 0.0, 0.6349, 2.5, 0.5456, 9.0, 9.0, 2, 260.0, 260.0
point.2=1, -9.88, 4.31, -4.0, 1574.8, 2, 1.70, 0.0, 0.6349, 2.5, 0.5456, 9.0, 9.0, 3, 260.0, 260.0

Can someone who has been suffering the bounces try this on their set-up and see if it makes any difference. I have so far, not looked at landing characteristics with these values.

Edit: Well I checked out a landing and the phrase "bounced like a cheque came to mind" - damn it. I'm guessing that the solution lies somewhere between the two sets of figures.

[John Young]

You might find the compression values of 0.6349 too high Stew, particularly on landing. From what I have read the value shouldn't really exceed 0.3. There is no physical compression built into the undercarriage in the model. However, AirWrench does show the compression as specified in the aircraft.cfg file.

So far 617 people have downloaded the FS9 version of the F-111. No one has posted a problem at ACG or e-mailed me (the contact points for help given in the manual). Despite 2 days of trying to see the problem, I just can't:



The first screen shot above is the parked state immediately after a re-load to a new time to eliminate any effects of a saved situation. The static pitch and static_cg height are spot on - the aircraft do not drop at all and sit right. In the take-off shot, the aircraft rotates smoothly and there is no bounce or puff of smoke. The aircraft lands on the main wheels with the expected puff of smoke and then settles two seconds later onto the nose wheel. There is no bounce whatsoever. I have not seen one anywhere in 2 days of observation.

I can't understand this and it's quite soul destroying. I don't really want to mess with the files anymore because I can't tell if I have solved a problem I don't have. I might actually make the situation worse without knowing it. It's a bit soul destroying really.

All I can do is sit and wait to see if you guys can solve the problem for yourself. I appreciate the work you are putting in to do that.

John

[Stewart Pearson]

Thanks for all your efforts John....................it's an impossible task to try and fix a problem you're not experiencing yourself.

The figure I used (0.6349) was actually a misread on my part from another AI cfg file.

However, as it solved the bounce on take off problem, I figured to use it as a starting point and begin making changes.

Don't you fret John, you've done a super job mate and if some of us are experiencing small probs, it's not a biggie.

You've done more than enough. I'm sure one of us will "crack it" and post the results here. That way if you do get any contacts/emails through ACG, you'll have the answer to hand.

Thanks again.

[Stewart Pearson]

By george, I think (note that) I may have cracked it!!!!

Have attached my aircraft cfg - can someone (with the bouncies) test it on their system please?

For those technically minded I changed the following;

From

reference_datum_position = 0, 0, 0
empty_weight_CG_position = 0, 0, 0

To

reference_datum_position = 0, 0, 0
empty_weight_CG_position = -5.00, 0, 1.0

+++++++

From

;Moments of Inertia
empty_weight_pitch_MOI = 50000
empty_weight_roll_MOI = 45000
empty_weight_yaw_MOI = 70000
empty_weight_coupled_MOI = 0.0


To

;Moments of Inertia
empty_weight_pitch_MOI = 90000
empty_weight_roll_MOI = 45000
empty_weight_yaw_MOI = 90000
empty_weight_coupled_MOI = 0.0

From

Center1 = -41.4, 0.0, -1.5, 359.0, 0.0
LeftMain = -36.3, -10.0, -1.5, 268.5, 0.0
RightMain = -36.3, 10.0, -1.5, 268.5, 0.0

To

[fuel]
Center1 = -6.9, 0.00, -1.5, 359.0, 0.0
LeftMain = -1.8, -10.0, -1.5, 268.5, 0.0
RightMain = -1.8, 10.0, -1.5, 268.5, 0.0

Contact points remain the same as John's update.

Now I haven't got a clue, which (if any) of these changes did the trick, but together with the change in contact points from John, it seems to perform okay dokey on my system.

[delbydoo]

Got it, thanks Stewart.....I'll have a look tomo..z.zz..z.zzzzzzzzzzzzzzzzz

[Chrisb]

Stew,

Oooh, now a cfg technician.

I have tried your cfg and I now have NO bumpy taxying, NO rubbish take off and NO bumpy effect filled landing. All is smooth and clear. I have only just discovered the spoiler devices on the wings upon landing because before they were obscured by all the effect smoke. The only thing I have noticed is that it is still taking off at runway marker three at Lakenheath, which is shorter than the F-15E.

Chris

[John Young]

Phew, I can't tell you how relieved I am this morning Stew. It was brave of you to tamper with the MOI - I normally use the values that AirWrench gives me. Thank you and to Chris also for testing your result. I also ran a test too this morning and can confirm that I have no problems with your file. I notice though that you have swapped the afterburner effect for the fx_f16_ab.fx. It's a better looking effect than mine, although it needs moving back a tad into the jet pipes. I don't own the copyright to that effect however, but Graham at flightsimmer.com (PAI) did give me permission to include it along with their GR1 in my Marham 1993 pack. I'll drop him a PM and ask him if I can stretch things a bit and include it in the F-111 pack as well.

I also made a few tests with the empty weight of the aircraft to get the aircraft further down the runway before rotation. Increasing it from 14000 to 18000 extends the take off distance to about half the runway length. You could push it a bit further but that value gives a safe margin to stop in when landing. This is the entry:

[WEIGHT_AND_BALANCE]
max_gross_weight = 20450.0 // (pounds)
empty_weight = 18000.0 // (pounds)

The maximum gross weight isn't used in AI aircraft. I think I'm right also about the fuel weight and position - it's also not used. Have you ever known an AI aircraft to run out of fuel? To verify the irrelevance, I put a massive 2000 gallons into the right tank and positioned it at a ridiculous 100 ft behind the aircraft. It made no difference to take-off or landing at all. No need to change the values then in your file.

Looking after the grandchildren today, but I'll finish off the wing root glove remapping next. Hopefully by then, other people with the bounce would have tried your file and confirmed OK. I can then release a Version 2.

Thanks again Stew and Chris.

John

[Chrisb]

John

It had to happen. The model is so good. All credit must go to Stewart though. I merely took his cfg and commented on the result.
The point about the take off distance may be a small point but it also lands and slows in quite a short distance just beyond the centre taxiway at Lakenheath. This means that it taxies slowly off the end of the runway and therefore causes some overshoots by the following aircraft. If it is extended a little that would reduce that slow period too.

Chris

[bismarck]

Hello, just a quick test on my side, all work fine also for me.
Thanks Stew and all. I was working on it, you saved me a lot of test

Giorgio

[delbydoo]

Stewie, this one is especially for you.........





Works a treat for me, one teeny weeny little bounce on the nose wheel after landing......barely noticeable.

Thanks a lot mate. Happy.

[Stewart Pearson]

I'm chuffed that it seems to have worked guys.

As I said, not a clue about the how or the why, just kept changing things until I got it smoothed out.

I am surprised that those members in the UK weren't calling the Police reporting disturbances last night..............after about 3 hours, the language at "Chez Stew" became a tad choice at times.

Daryl, I was aware of the little after landing "hop" but figured that it added a wee bit of realism............well, truth be told, I haven't been able to get that smoothed out completely

John, maybe now you can relax mate and move on to your next project. Thanks once again for a super model and for all your work.

[delbydoo]

after about 3 hours, the language at "Chez Stew" became a tad choice at times.

Really? From a Scot? Nah.......don't believe it

[Stewart Pearson]

after about 3 hours, the language at "Chez Stew" became a tad choice at times.

Really? From a Scot? Nah.......don't believe it

Yeah I'm using a brand new version of FS9.

It's called "Aww you awkward b*****d Flight Simulator 2004"

[mikewmac]

John: Yesterday I installed and tested your original, outstanding JYAI F-111 model/FDE at Miramar (KNKX) and it worked fine for me with no taxi, takeoff and/or landing bounce/smoke when viewed with MS's Traffic Toolbox Explorer. I did induce some taxi, takeoff and landing bounce/smoke when I used Traffic View Board (TVB) and switched to view your AI F-111 as it taxied, took off or landed, but this is a typical occurrence when switching between AI when observing them with TVB.

I'm currently working on several other AI FDE's, but as soon as I have some free time I will test your updated JYAI F-111 FDE to see how it works also.

Eventually I might create my own personal AI FDE for your outstanding JYAI F-111 to use with textures for the F/B-111A's based at the old Plattsburgh AFB, if and when they become available from some motivated painter. Years ago I used to fly over Plattsburgh AFB on my way to Clinton County Airport from Burlington when the F/B-111A's were based there. They were an awesome sight from directly above at 3000 feet.

Stew: I'm happy to see that you were able to eliminate most of the JYAI F-111 bounce and/or smoke that you were observing and that using my standard ;Moments of Inertia settings, probably from my WSAI F-15E FDE, helped. I use those settings in all of my AI FDE's to stabilize AI models both on the ground and in flight. As John states, the change of the JYAI F-111 [fuel] settings to those from my WSAI F-15E FDE were probably superfluous. Also as you stated, the 0.6349 that you used earlier from my WSAI F-15E FDE wasn't a static compression setting and wasn't intended to be used as such.

[Stewart Pearson]

Stew: I'm happy to see that you were able to eliminate most of the JYAI F-111 bounce and/or smoke that you were observing and that using my standard ;Moments of Inertia settings, probably from my WSAI F-15E FDE, helped. I use those settings in all of my AI FDE's to stabilize AI models both on the ground and in flight. As John states, the change of the JYAI F-111 [fuel] settings to those from my WSAI F-15E FDE were probably superfluous. Also as you stated, the 0.6349 that you used earlier from my WSAI F-15E FDE wasn't a static compression setting and wasn't intended to be used as such.

Hi Mike,

I think I actually pinched the values from the NB F-14 cfg file. Truth be known mate, I pinched values from loads of different developers and just tried mixing and matching, until I got some that did the trick.

So, are you saying that changing the fuel tank position, relative to cog doesn't have any effect at all?

[mikewmac]

Stew: I'm happy to see that you were able to eliminate most of the JYAI F-111 bounce and/or smoke that you were observing and that using my standard ;Moments of Inertia settings, probably from my WSAI F-15E FDE, helped. I use those settings in all of my AI FDE's to stabilize AI models both on the ground and in flight. As John states, the change of the JYAI F-111 [fuel] settings to those from my WSAI F-15E FDE were probably superfluous. Also as you stated, the 0.6349 that you used earlier from my WSAI F-15E FDE wasn't a static compression setting and wasn't intended to be used as such.

Hi Mike,

I think I actually pinched the values from the NB F-14 cfg file. Truth be known mate, I pinched values from loads of different developers and just tried mixing and matching, until I got some that did the trick.

Stew,

Those settings are the same in almost all of my jet fighter AI FDE's, so the NBAI F-14 would have had the same ones. I have no problem with you using them. I was just pointing out that I use those higher ;Moments of Inertia settings in my aircraft.cfg files to help stabilize AI models and they probably helped eliminate your bounce and smoke problems. Personally, I didn't have those problems with the JYAI F-111, so, like John, I couldn't really address it effectively.

[Stewart Pearson]

Stew,

Those settings are the same in almost all of my jet fighter AI FDE's, so the NBAI F-14 would have had the same ones. I have no problem with you using them. I was just pointing out that I use those higher ;Moments of Inertia settings in my aircraft.cfg files to help stabilize AI models and they probably helped eliminate your bounce and smoke problems. Personally, I didn't have those problems with the JYAI F-111, so, like John, I couldn't really address it effectively.

Ah, so it may well have been the MoI changes that did the trick?

I knew you didn't have a problem Mike, I was just trying to establish what all these changes were and the effect they had on aircraft behaviour and wanted to be sure you knew where I got them from, in case there was a difference.

I just knew that I didn't get the figures from the WSAI F-15E.....................................I haven't installed it yet!!!

My approach to the problem last night was very much a "I fire an arrow in the air, it comes to rest I know not where" one.