In most fighter jets, pilots have direct command of the main control surfaces (ailerons, elevons etc.) but the slats are controlled automatically by the fly-by-wire system without any input from the pilot.
For the most part, they are programmed to deploy at lower speeds to aid in generating additional lift, as well as during high alpha (angle of attack). I used 4 hinges (attached to 4 sperate slat surfaces) with the expression below to accomplish this function in SimplePlanes.
(1 - inverselerp(100, 250, TAS)) + ((AngleOfAttack < -0.5) & TAS > 50 ? (-AngleOfAttack / 30) : 0)
In English, the Hinge starts at its full down position (1). At a true airspeed of 100m/s, the flaps begin to retract linearly back to their fully up position (0) through a true airspeed of 250. In addition, if the angle of attack is less than -.5 (pitch up), and the true airspeed is greater than 50, then the input is the Angle of Attack divided by 30.
Things you can edit to your crafts requirements is the range through which the slats will move up (inverselerp(lower TAS limit, upper TAS limit, TAS), and the amount of input each AoA degree provides (AnlgeOfAttack / X)- higher numbers makes it less sensitive, and lower numbers makes it more sensitive.
SP interprets AOA erratically when the craft isn't moving, hence why I added the TAS > 50 condition- to keep the slats from flailing around when stationary lol. I recommend leaving this above 0.
Specifications
Spotlights
- DeathStalker627 4.6 years ago
- CRJ900Pilot 4.6 years ago
- RussianAce 4.6 years ago
General Characteristics
- Predecessor Funky Trees Challenge
- Successors 1 airplane(s) +14 bonus
- Created On Windows
- Wingspan 32.5ft (9.9m)
- Length 43.8ft (13.4m)
- Height 11.4ft (3.5m)
- Empty Weight 16,361lbs (7,421kg)
- Loaded Weight 23,915lbs (10,847kg)
Performance
- Power/Weight Ratio 2.819
- Wing Loading 68.3lbs/ft2 (333.5kg/m2)
- Wing Area 350.1ft2 (32.5m2)
- Drag Points 3859
Parts
- Number of Parts 105
- Control Surfaces 6
- Performance Cost 763
Well I appreciate your willingness to help but I've just decided by the help of another friend that I'll just set these slats to vtol. If I do more slats in the future I will try to use a rotator instead of a piston and I'll try to use a code. But this time we can just leave it. Thank you though! @lemoose
Send me the plane youre working on and ill be happy to help. Similar code should work for the pistons too but if you have any literature handy on exactly how it behaves in the plane it would certainly help get it just right @Hedero
Yeah, well it's fine. I'll do something about it. Thanks for trying! @SnoWFLakE0s
@Hedero
.
Probably, sounds like it.
I'm using pistons instead of rotators. Would that be the reason it's not working? Cause the slats will shift forward and backwards several times before either sitting full forward or fully retracted. @SnoWFLakE0s
@Hedero
.
Which part of your attempt didn't work? Looks fine to me, although it looks like it'll only work for negative angles of attack.
Except this code used on the aircraft is far more complex then what I need. All I need is for the slats to deploy when exceeding (x) degrees. I don't need them to deploy at low/high speeds or whatever. I tried "AngleOfAttack < 50" but it didn't work. Warhawk95 told me to try it but whenever I put code in it doesn't seem to work as I wish. And of course if you don't feel like messing with code right now that's perfectly fine. @SnoWFLakE0s
@Hedero
.
The system provided here would work pretty well for your purposes. The description provides usage instructions, if you see that it doesn't work come up with a set of requirements and I'll figure something out.
Hey bro, I'm asking you 'cause I don't know if LeMosse is still active on the site or not. But I am making a basic prop plane called the M.S. 1500 Epervier and it utilizes slats. I was wondering what a good code function would be for them. I believe they only deploy based on angle of attack, as they aren't very complex. Thanks ft god. @SnoWFLakE0s
Wow I love what you did to the intakes!
Neat
Yep. I haven’t seen Lerp/inverselerp used too much. Inverselerp is definitely a powerful function though. To be honest I’m surprised that lerp and inverselerp are so rare. I guess me and snowflake have been using funky trees for systems that don’t really call for lerp or inverselerp.
@spefyjerbf @SnoWFLakE0s ha really? I also use it for the flaps on this plane (and my f35 submission) as well as on the planes ive uploaded just this month alone.
@SnoWFLakE0s beat me to the comment about the inverselerp. Great work!
Thanks! Much appreciated! @CRJ900Pilot
Woah, that’s cool! I might add this system on my upcoming project! I’ll credit you @lemoose
Cool. I think this is the first time I've seen anyone use inverselerp. Noted!
I was too lazy to do this lol
SmArT
As long as the COM isn’t too far ahead or behind from where the slats are attached, they do function! @CRJ900Pilot
Is this functional or just decorative? Either way its really cool!
@lemoose
I'll try them on my next plane.
Yea you would unfortunately. I had to redonthe wings for all the planes i retrofit these slats and it was a real pain lol @ArcturusAerospace
@lemoose
Now I would use it, but then I'd have to redo the wings of my fighter :(
The hinge already has the code you need. Just attach it to the main wing of your airplane and on the moving end attach the slat surface. @ArcturusAerospace