Alpha Jet A Project
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you could create a AFM -with NFBW aero module, like the A10, but it is extremly difficult, and the result can be disapointing.
HOWEVER.
It will be always better to create AFM , noeone can really fly OFM those days , everything is shit.
As always, first create good OFM for performance , then AFM for handling.
AFM alphajet can be based on the AV8 one
and yes topolo, you can do a lot of things with AFM files, and by tweaking them, i could even desactivate the FLCS behind ,but that requires you tweak the AV8 / F16 AFM to be stable and not unstable….
that is doable
Topolo - You are not alone , i will continue to improve OFM file from what i have but i don’t have accurate AirFoil data for the Alpha Jet neither CD, alfa and beta indexes. Do you have any documentations or tutorials how to read and interpret the data file?
Mav-jp- You are correct :), even the AJet will benefit from AFM data. No FLCS but LG damper and suspension and other non FLCS related data. And thank you for the tip. I will try to use AV8 as a baseline for the Ajet.
Anyone need the 3DS max files that i have now?
Here i can find accurate databases for the CL and CD indexes?
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Topolo - You are not alone , i will continue to improve OFM file from what i have but i don’t have accurate AirFoil data for the Alpha Jet neither CD, alfa and beta indexes. Do you have any documentations or tutorials how to read and interpret the data file?
Here i can find accurate databases for the CL and CD indexes?OFM file (for what I’m concerned) is mainly (if not only) CL(M,AoA), CD(M,AoA) a Thurst(M,Z) tables, so I’m curious (and here, believe me, it is really not sarcastic, just really curious, because public data are really not easy to find) to know how and from which data you are improving AJet OFM
First solution, you have RL aero data (usually measured in wind tunnel and then remapped using test flight, like it does exists for some US or Sovient a/c) and engine performance charts (mix of engine test bed and test filght).
Second solution: yo have the AJet Performance Charts (EM charts + Climb charts + Acceleration charts + Range/Endurance) and a computational methodology to reverse engineer the aero and thrust laws from performance curves
Which of the two are you following ?PS1: Airfoil data will give you near to nothing on the full a/c aero, so do not spend to much time on this if you want to fit the flight envelope and perf.
PS2: @Mav I know what you can do with an AFM, I just want to mention that it does not seems to me really affordable to build an AFM for a non FLCS a/c all over sub and transonic domain that will give to the a/c the RL flavor. The best we can do IMO is to fit performance with an OFM, then give a more pleasant handling (but not a more realistic handling) -
OFM file (for what I’m concerned) is mainly (if not only) CL(M,AoA), CD(M,AoA) a Thurst(M,Z) tables, so I’m curious (and here, believe me, it is really not sarcastic, just really curious, because public data are really not easy to find) to know how and from which data you are improving AJet OFM
First solution, you have RL aero data (usually measured in wind tunnel and then remapped using test flight, like it does exists for some US or Sovient a/c) and engine performance charts (mix of engine test bed and test filght).
Second solution: yo have the AJet Performance Charts (EM charts + Climb charts + Acceleration charts + Range/Endurance) and a computational methodology to reverse engineer the aero and thrust laws from performance curves
Which of the two are you following ?None really
I used the G4 (he closest plane in the database i guess) as a baseline for CD and CL. And from there i tweak bit by bit until performance and thrust are close from other Alpha Jet Sims (X-PLANE and DCS). But again i do not have accurate data and since airfoils don’t match the database inputs they are useless. Also Ajet its a particular case of 2 NACA airfoils in one wing. The root and tip wings have diferente CL and CD indexes.Do you have any idea how to improve this?
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PS2: @Mav I know what you can do with an AFM, I just want to mention that it does not seems to me really affordable to build an AFM for a non FLCS a/c all over sub and transonic domain that will give to the a/c the RL flavor. The best we can do IMO is to fit performance with an OFM, then give a more pleasant handling (but not a more realistic handling)as i was saying if you tweak the Cm data to be stable , then we can totally remove the FLCS and you will have what you want, with correct triming behavior etc…
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FYI , in AFM data
1 #has NASA Model
Removes any FLCS interaction, you have direct control (see A10 AFM)
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as i was saying if you tweak the Cm data to be stable , then we can totally remove the FLCS and you will have what you want, with correct triming behavior etc…
I do not say it is not possible, just say it’s not affordable
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Just to make is perhaps a bit clearer :
1- Gather as much as possible of fight dynamics data of Alpha-Jet E.
2- Take A-10 OFM (two engines, no FBW)…
3- Tweak this OFM to reach basic Alpha-Jet E performances
4- Once you have something accurate with OFM, pickup F-16 AFM.
5- You will be able to tweak a lot of stuff of the aircraft behavior. For example, gear pistons animations shall be tweaked there
6- Doing this, you will probably note that your DOFs are not well configured. You will need to readjust them to have something realistic. (I will probably send you FCK-1C gears only .3dsmax model to check how it’s supposed to work).
7- Everytime you adjust something, check it in BMS. Once it’s good, go to the next phase.Here you go !
Radium
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Just to make is perhaps a bit clearer :
1- Gather as much as possible of fight dynamics data of Alpha-Jet E.
2- Take A-10 OFM (two engines, no FBW)…
3- Tweak this OFM to reach basic Alpha-Jet E performances
4- Once you have something accurate with OFM, pickup F-16 AFM.
5- You will be able to tweak a lot of stuff of the aircraft behavior. For example, gear pistons animations shall be tweaked there
6- Doing this, you will probably note that your DOFs are not well configured. You will need to readjust them to have something realistic. (I will probably send you FCK-1C gears only .3dsmax model to check how it’s supposed to work).
7- Everytime you adjust something, check it in BMS. Once it’s good, go to the next phase.Here you go !
Radium
OFM a10 , why ???
Do not take f16 AFM , take AV8
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OFM a10 , why ???
Do not take f16 AFM , take AV8
A10 : no FBW, 2 engines ? No ?
You think that AV-8 is better ? Ok then
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A10 : no FBW, 2 engines ? No ?
You think that AV-8 is better ? Ok then
It is because you spoke about using the A10 OFM file. So it is better to use the A10 AFM file or the AV8 AFM file (as Mav-JP recommendation) but no OFM files at all
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Keep in mind that we already had a working dat file for the POH theatre. I suppose i can use some data from a10 data file but the original AMX data file in the POH was already improved (somehow)
I just teak a little more.
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@Bad:
It is because you spoke about using the A10 OFM file. So it is better to use the A10 AFM file or the AV8 AFM file (as Mav-JP recommendation) but no OFM files at all
Guys please don’t spread wrong information
First : do proper OFM , no need to copy anyone , create it from scratch
Then : create AFM based on av8afm since I worked on it already to make it stable and as neutral as possible
Third : if you wish to remove FLCS you need adjusting the Cm a little bit
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I came up with this values can someone comment?
alpha CL CD CDp CM Top_Xtr Bot_Xtr
–---- -------- --------- --------- -------- -------- --------
-19.000 -1.3961 0.05759 0.05328 -0.0445 1.0000 0.0132
-10.000 -0.9406 0.01413 0.00819 -0.0180 0.9884 0.0315
-5.000 -0.4036 0.01005 0.00338 -0.0121 0.7357 0.0507
0.000 0.1267 0.00774 0.00162 -0.0056 0.3503 0.5734
2.500 0.4002 0.00822 0.00219 -0.0038 0.2321 0.7737
5.000 0.6714 0.00915 0.00336 -0.0014 0.1855 0.9206
10.000 1.2291 0.01386 0.00780 -0.0055 0.0913 1.0000
15.000 1.5252 0.02684 0.02117 0.0228 0.0421 1.0000
19.000 1.4702 0.08052 0.07626 0.0118 0.0330 1.0000 -
How did you come up with those values ?
When I played with the SU-27/30 OFM and then AFM I used Coefficients provided by someone with some knowledge of the subject.
There was more then enough other data to be measured, calculated, and then tested/verified many times over to keep me busy for a few years.
Converting Thrust data alone provided a goodly learning curve. And then there was hit-box, landing gear mapping, wheel rotation etc etc etc.
I had a lots of fun but in the end was let down by the model non-maker. Bit of a sob story really.
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How did you come up with those values ?
When I played with the SU-27/30 OFM and then AFM I used Coefficients provided by someone with some knowledge of the subject.
There was more then enough other data to be measured, calculated, and then tested/verified many times over to keep me busy for a few years.
Converting Thrust data alone provided a goodly learning curve. And then there was hit-box, landing gear mapping, wheel rotation etc etc etc.
I had a lots of fun but in the end was let down by the model non-maker. Bit of a sob story really.
Do not worry, Su-27 family will have a brand new OFM/AFM soon (at least some of them)
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Do not worry, Su-27 family will have a brand new OFM/AFM soon (at least some of them)
When I started (2012/13 I think ) no one seemed interested, at least I had a go at it. And as I have stated I had a lot of fun trying.
Look forward to flying it soon (3-4 weeks) ?
PS: way too many emo’s now. Cull the emo’s, death to unused emo’s.
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How did you come up with those values ?
When I played with the SU-27/30 OFM and then AFM I used Coefficients provided by someone with some knowledge of the subject.
There was more then enough other data to be measured, calculated, and then tested/verified many times over to keep me busy for a few years.
Converting Thrust data alone provided a goodly learning curve. And then there was hit-box, landing gear mapping, wheel rotation etc etc etc.
I had a lots of fun but in the end was let down by the model non-maker. Bit of a sob story really.
That’s my biggest problem.
Without any IRL accurate data im using NACA profiles to calculate CL and CD.
The two problems is that AJET itself as 2 different airfoils and CL and CD can´t be deduced only from wing geometry.
Also CD in BMS don’t have direct relation with RL CD adimensional values. By a factor of x3.2 at least.
Unless anyone can came with RL data it will a pure exercise of trial and error.
BTW - Tested a AV8 AFM file in the Ajet and violá worked.
Of course the Values are all messed up but at least flew
One other question - How to increase loss of momentum during a hard turn. Right now even with low trust the plane keep a 8 g turning without losing air speed, but in strait line max speed is M0.85 a sea level so i guess drag and thrust are ok. Any clues?
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Hello,
What about just going further the model ?
For now, from what I see, only 10% of the job is done.
Please consider :
- Finish the model
- Unwrap
- Textures
- DOF
- Switch
- Licenseplates
- LODs
Flight model will only come there.
Regards,
Radium
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Hello,
What about just going further the model ?
For now, from what I see, only 10% of the job is done.
Please consider :
- Finish the model
- Unwrap
- Textures
- DOF
- Switch
- Licenseplates
- LODs
Flight model will only come there.
Regards,
Radium
Your right
Its taking a lot of time because i’m not a 3DS guy.
I’m starting to learn now how to manage more complex task.
But you are right first tings first
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Your right
Its taking a lot of time because i’m not a 3DS guy.
I’m starting to learn now how to manage more complex task.
But you are right first tings first
Do I understand that you are a Blender guy ?
(One more ? :()