[1.3.1] Ferram Aerospace Research: v0.15.9.1 "Liepmann" 4/2/18

[Forty21112]

@Ferram: Okay, so is there a way to restore the axis? I just assumed that the vectors are the arrow that was pointing up. Sorry about that, I'm new to this complicated stuff.

[GabeTeuton]

Well guys, I finally did it, and guess what? I found what I believe was the problem... SP+ parts , those awesome parts I believe have some issues, not sure if the issues are related to those parts being added to the game, or to FAR, at least in my ksp... I'll listen to what you have to say...

I thought that i should used only mk1 parts to make the ssto and give it a try... here it is...

(i'm not sure how to make the entire image in the album show instead of half of it)

[spoiler=]

Javascript is disabled. View full album

Edited October 16, 2014 by GabeTeuton

[GabeTeuton]

Well guys, I finally did it, and guess what? I found what I believe was the problem... SP+ parts , those awesome parts I believe have some issues, not sure if the issues are related to those parts being added to the game, or to FAR, at least in my ksp... I'll listen to what you have to say...

I thought that i should used only mk1 parts to make the ssto and give it a try... here it is...

(i'm not sure how to make the entire image in the album show instead of half of it)

[spoiler=]

http://imgur.com/a/biq7I

AWESOME, just finished the return mission successfully... lost both vertical stabilizes during reentry, and overshooted ksc by 450 km +/-, but had 300 units of liquid fuel to spare... so awesomeeeeee!!!!!

Still disappointed i wasn't able to make it work with the SP+ parts... will wait for your suggestions!

[Wanderfound]

AWESOME, just finished the return mission successfully... lost both vertical stabilizes during reentry, and overshooted ksc by 450 km +/-, but had 300 units of liquid fuel to spare... so awesomeeeeee!!!!!

Still disappointed i wasn't able to make it work with the SP+ parts... will wait for your suggestions!

Post screenshots for each ship with the FAR stability derivatives analysis showing, and we'll see if we can figure out exactly what the problem was.

Do one set with temperature zero, density 0.5 and speed Mach 1.5 (this is the low altitude ascent one), another with temperature -20, density 0.04 and speed Mach 5 (just before the rockets go on) and a third set with temperature -20, density 0.01 and speed Mach 6 (just after the rockets go on).

[GabeTeuton]

Post screenshots for each ship with the FAR stability derivatives analysis showing, and we'll see if we can figure out exactly what the problem was.

Do one set with temperature zero, density 0.5 and speed Mach 1.5 (this is the low altitude ascent one), another with temperature -20, density 0.04 and speed Mach 5 (just before the rockets go on) and a third set with temperature -20, density 0.01 and speed Mach 6 (just after the rockets go on).

Copy that! Will do tomorrow as right now i'll go to work !!!

[Wanderfound]

Copy that! Will do tomorrow as right now i'll go to work !!!

While you're at it, have a look at what the CoM does on the Mk2 plane when the front tank is empty but the rear is full. Your dCoM is balanced, but your 1/2dCoM might not be.

[SkyRender]

I guess it's somewhat satisfying to know that the exaggeration of the problem is in fact something caused by the new parts as I surmised. Probably gonna be a pain for Ferram to fix, too...

[Wanderfound]

I guess it's somewhat satisfying to know that the exaggeration of the problem is in fact something caused by the new parts as I surmised. Probably gonna be a pain for Ferram to fix, too...

"Failure to design in a manner that adequately accounts for the effects of body lift" is not something for Ferram to fix. They're working fine for me.

[nli2work]

this mod is making me thinking I should get an analogue controller instead of using keyboard to fly.

[jrandom]

this mod is making me thinking I should get an analogue controller instead of using keyboard to fly.

YES! I bought a flightstick (Logitech Extreme 3D Pro) for the express purpose of flying planes. Combined with the Razor Nostromo I have key controls for rocket flight, flightstick control for planes, and enough buttons to map to all my custom actions, throttle, etc. I rarely ever have to reach for the keyboard during flight.

[SkyRender]

"Failure to design in a manner that adequately accounts for the effects of body lift" is not something for Ferram to fix. They're working fine for me.

Actually, the problem isn't the fact that the SP+ parts all have lift. I designed a perfectly functional SP+ plane in 0.24.2 by using the then-stock control surfaces instead of the ones included with SP+. With stock flaps, the phantom roll problem basically didn't exist, but even in 0.24.2, the SP+ elevon flaps would cause phantom roll effects. Even if you disable roll control on those flaps, they still cause your craft to roll randomly with far greater intensity than the C7 flaps ever did.

[jrandom]

I built this aircraft using SP wings and control surfaces and it flew beautifully after I reduced the maximum deflection angle.

[Wanderfound]

Actually, the problem isn't the fact that the SP+ parts all have lift. I designed a perfectly functional SP+ plane in 0.24.2 by using the then-stock control surfaces instead of the ones included with SP+. With stock flaps, the phantom roll problem basically didn't exist, but even in 0.24.2, the SP+ elevon flaps would cause phantom roll effects. Even if you disable roll control on those flaps, they still cause your craft to roll randomly with far greater intensity than the C7 flaps ever did.

This has three different types of SP+ elevons on it. Roll stability looks okay to me:

[ferram4]

@SkyRender: "Phantom roll?" I hope you have a test case for that, because I haven't seen any roll effects that can't be attributed to proper aerodynamics + flexing of the vehicle. And I ran into a lot of actual phantom roll rebuilding the wing interaction code.

[DivisionByZero]

I have a question - I'm not sure it should go here but the change-log indicated the intake parameters were altered, so I'll ask:

Is there a set of performance curves for the different air intake schemes? In principle, I'd expect the supersonic intakes to perform better at high velocity, but is that actually present in the code? Are there altitude and velocity curves for these things?

Thanks

[JackCY]

thumbs up on the stall visualization

[ferram4]

@DivisionByZero: No, it only applies to the drag applied to the intakes, not to anything else. They're otherwise just as broken as stock.

[SkyRender]

I've done some more testing to see if I can combat this crazy roll problem. Doubling the mass of the SP+ elevons seems to have helped, as well as halving their deflection strength. There's still a slight random roll during takeoff, but that happens in stock too.

[Matrix Aran]

A quick question: I've been thinking of a challenge for this upcoming weekend and I though about building something equivalent to the "tailless" McDonnell Douglas X-36 in KSP. Would it in theory be feasible to build such a thing with FAR running and set up the control surfaces in such a way that the craft was somewhat controllable? (read: the pilot can at least chose where to crash it)

[blowfish]

this mod is making me thinking I should get an analogue controller instead of using keyboard to fly.

Heh. I was just thinking how sore my finger was getting from trying to keep the nose of my plane up.

[velusip]

i have the exact same problem if i don't launch with SAS on, or give it a slight nudge to the right just after launch. i think there is something weird in how the physics system is settling stuff on the pad.

I too have noticed some unusual events on the launch pad with KSP 0.25 and FAR 0.14.3. The vessel breaks launching the pod at billions of meters per second. It's not very cool.

[DaMichel]

Heh. I was just thinking how sore my finger was getting from trying to keep the nose of my plane up.

Turn SAS off and use trim (ALT+WASD). It sounds like your plane is pretty stable (nosing down) so this should reduce your workload a lot. Use FARs flight assistant options if it is a bit too twitchy. I find the wing leveler very useful at times.

P.S. Ferram4, the latest updates fixed by issues with flaps & air brakes. Thanks!

Edited October 16, 2014 by DaMichel

[blowfish]

Turn SAS off and use trim (ALT+WASD). It sounds like your plane is pretty stable (nosing down) so this should reduce your workload a lot. Use FARs flight assistant options if it is a bit too twitchy. I find the wing leveler very useful at times.

P.S. Ferram4, the latest updates fixed by issues with flaps & air brakes. Thanks!

I usually use the FAR flight assistants in atmospheric flight and SAS on and off but trim sounds like it would be useful. Thanks

[ferram4]

@velusip: Reproduction steps and a log, please? Just saying, "X thing that shouldn't happen happens" doesn't help me find out what is wrong.

[jrandom]

A quick question: I've been thinking of a challenge for this upcoming weekend and I though about building something equivalent to the "tailless" McDonnell Douglas X-36 in KSP. Would it in theory be feasible to build such a thing with FAR running and set up the control surfaces in such a way that the craft was somewhat controllable? (read: the pilot can at least chose where to crash it)

Who cares if it's it's feasible? Do it anyway, it's the kerbal way! (Actually, I think I've built planes like this in the past...)