MAIW JGAI Saab MFI-17 Supporter Conversion Support

Joseph29 · Post by **Joseph29** » 22 Jul 2024, 02:40

Since there is no thread for the MFI-17 I will ask this question here.

I installed this plane in P3D v5.4 and I am having problems with it. When the plane taxi it bounces all over the place. I saw one plane bounce so high it was over the tops of the buildings and nose dived straight into the ground. The plane never took off because after bouncing around for like 30 seconds the plane disappeared.

jetpilot1980 · Post by **jetpilot1980** » 22 Jul 2024, 11:31

Usually when that happens it's a contact points issue... I took a quick look at the aircraft.cfg... One thing I have found is when the static_cg_height is at or above the abs value of the z coordinate of the landing gear contact point it can cause this issue... Looking at that I noticed that the gear is -3.96 and the static cg is 3.96; which could be the issue... Try changing the value to static_cg_height=3.00 and see if that helps...

Joseph29 · Post by **Joseph29** » 22 Jul 2024, 12:38

jetpilot1980 wrote: 22 Jul 2024, 11:31 Usually when that happens it's a contact points issue... I took a quick look at the aircraft.cfg... One thing I have found is when the static_cg_height is at or above the abs value of the z coordinate of the landing gear contact point it can cause this issue... Looking at that I noticed that the gear is -3.96 and the static cg is 3.96; which could be the issue... Try changing the value to static_cg_height=3.00 and see if that helps...

Thank you. I will try this either later on tonight or tomorrow (I don't have time now) and let you know if it works.

Joseph29 · Post by **Joseph29** » 24 Jul 2024, 02:46

I just tried changing the static_cg_height= to 3.00 and that didn't do anything. The planes still bounce wildly when they taxi.

Post by **John Young** » 24 Jul 2024, 05:07

It's not the static_cg_height you need to experiment with, but the empty_weight_CG_position (usually the X value). Are you sure you haven't changed anything in the original FDE that is causing the bounce - is there a generic problem with it?

John

Jim · Post by **Jim** » 24 Jul 2024, 09:48

Folks,

I have the same probem: bouncing all over the place.
I also had it when I tried my shoddy attempt at converting the original FS9 Norway/Denmark packs. I uninstalled them and awaited an official conversion...

Miljan's "Repaint MFI-17 Mushshak - RAFO (JGAI)" pack seems to work ok for me. (I must have converted the "no" model for it.)

So, now I have tried the aircraft.cfg file from Miljan with the new conversion pack and the bouncing has stopped. I have not tested thoghroughly though.
I cannot see any differences in the above mentioned values, but the layout of the files are quite different.

Is there a max character length for a row of text in the aircraft.cfg file?

Jim

Joseph29 · Post by **Joseph29** » 24 Jul 2024, 11:27

Jim wrote: 24 Jul 2024, 09:48 Miljan's "Repaint MFI-17 Mushshak - RAFO (JGAI)" pack seems to work ok for me. (I must have converted the "no" model for it.)

I found this in the download section, but it only has repaints no models.

Jim · Post by **Jim** » 25 Jul 2024, 12:49

I would use the model from the new conversion pack Joseph (but at the time would have used a self-converted model from the FS9 Norway pack).

Anyway, what I said does NOT work. I'm getting inconsistent results today at best.

Jim · Post by **Jim** » 25 Jul 2024, 14:38

Sticking with the new conversion pack, I'm getting better behaviour with a value 0.5 to 2, eg...
empty_weight_CG_position = 1, 0, 0

(They still misbehave if I increase the sim speed to x2 or x4.)

Post by **John Young** » 25 Jul 2024, 15:32

That might be due to the MOI values Jim. Now that's a science in it's own right that I have never really grasped, so I either use the values that MAIW have regularly used in the past for different aircraft types, or I calculate them with AirWrench, which is not always useful because they are produced for a user-flyable aircraft.

I don't know if these will help, but they are the values from my Grob Prefect:

empty_weight_pitch_MOI = 30000
empty_weight_roll_MOI = 18200
empty_weight_yaw_MOI = 36500
empty_weight_coupled_MOI= 0.0

John

Jim · Post by **Jim** » 26 Jul 2024, 10:52

Thanks John,

The MOIs gave the same improvement as the CG adjustment, so I went the whole hog and swapped in your Prefect's [WEIGHT_AND_BALANCE] , [contact_points] & [airplane_geometry] sections entirely and that seems to work perfectly even at x2, x4 speeds.

Which is handy for an impatient tester

I hope Joseph29 gets his to work too.

Post by **gsnde** » 26 Jul 2024, 11:15

Post support related comments for the MAIW JGAI Saab MFI-17 Supporter Conversion package in this thread.

Post by **John Young** » 26 Jul 2024, 14:38

Jim, I'm glad that worked. While you may want to try and engineer a new FDE each time, I have always found it easier to pick from a stock of proven ones for each aircraft type that can be adjusted (contact points and speeds) as needed. I remain indebted to Michael Macintyre who worked with me to produce some fast jet stuff that I have used over again. I also have a favourite twin jet airliner FDE that has served me well from the work that Steve did with me on the Boeing Poseidon.

John

Post by **gsnde** » 27 Jul 2024, 10:17

An updated version with this fix included has been published

Joseph29 · Post by **Joseph29** » 27 Jul 2024, 13:56

Just wanted to say thank you. The new values are good.