[0.24] Spaceplane Plus 1.3

[Turnip199]

Am I doing something wrong, or do the wings provide very, very little lift? Adding a tiny stock wing throws around the CoL a ton, and rotation speeds are in the hundreds of m/s for even small aircraft

[Wanderfound]

Am I doing something wrong, or do the wings provide very, very little lift? Adding a tiny stock wing throws around the CoL a ton, and rotation speeds are in the hundreds of m/s for even small aircraft

Depends; stock aero, NEAR or FAR?

Screenshots of the plane with CoM/CoL/CoT indicators on would help.

[Turnip199]

Depends; stock aero, NEAR or FAR?

Screenshots of the plane with CoM/CoL/CoT indicators on would help.

NEAR

Tiny wings shouldn't move the CoL as much as it is compared to such large wings. Without the stock wings (image 1), the front wheel starts to lift off at 186 m/s, it doesn't lift off until it's past the end of the runway, and even then it doesn't get positive rate of climb.

[King_komodo93]

Hidden parts are a good thing – that means Module Manager is making parts compatible with different mods. For example, SP+ will remove all the stock lift configs from it's parts and replace them with FAR, but only if you have FAR installed.

The output log is too large to post here. Could you upload it to a site like Pastebin or Dropbox and link to it here?

Good point didn't notice that I only put part of it there (second dumbest thing I did yesterday) here you go. https://www.dropbox.com/s/1zekkyj4ez01kqz/output_log.txt

[Master Tao]

It's definitely having issues loading the part models. Maybe you have a corrupted download? Could you download from Dropbox or Mediafire instead?

[Renegrade]

Am I doing something wrong, or do the wings provide very, very little lift? Adding a tiny stock wing throws around the CoL a ton, and rotation speeds are in the hundreds of m/s for even small aircraft

Actually the wings did seem kinda low-lift to me as well vs. stock wings in FAR (especially considering their size) .. thought it might have been my imagination, but now I'm not so sure..

[Joachim]

Hidden parts are a good thing – that means Module Manager is making parts compatible with different mods. For example, SP+ will remove all the stock lift configs from it's parts and replace them with FAR, but only if you have FAR installed.

The output log is too large to post here. Could you upload it to a site like Pastebin or Dropbox and link to it here?

Neat plane. Haven't seen a joined wing in a while.

I was trying to be super efficient in terms of lift, stability etc. Normally I have LOADS more engines lol

[Wanderfound]

Actually the wings did seem kinda low-lift to me as well vs. stock wings in FAR (especially considering their size) .. thought it might have been my imagination, but now I'm not so sure..

Should be easy to test: put stock deltas on in SPH, screenshot, replace with SP+ deltas, compare.

[Hodo]

NEAR

http://i.imgur.com/oY4Lhws.jpg

http://i.imgur.com/Ql1hdm3.jpg

Tiny wings shouldn't move the CoL as much as it is compared to such large wings. Without the stock wings (image 1), the front wheel starts to lift off at 186 m/s, it doesn't lift off until it's past the end of the runway, and even then it doesn't get positive rate of climb.

I have a suggestion to help with your problem. You could try removing the front two fuel tanks and replace them with just structural parts, this would reduce the mass at the front of the craft moving the CoM further back. The other option is to move your wings forward, which would be ugly but would fix the problem. Delta wing designs tend to generate bulk of their lift towards the rear of the wing. Which I find odd, but what do I know.

[King_komodo93]

It's definitely having issues loading the part models. Maybe you have a corrupted download? Could you download from Dropbox or Mediafire instead?

DL'd from all of them have had the same problem regardless of location.

[Master Tao]

DL'd from all of them have had the same problem regardless of location.

Ah! I think I found it. You've got Firespitter and ModuleManager in double-deep GameData folders: KSP\GameData\GameData\. Try bumping them up a level.

[Wanderfound]

DL'd from all of them have had the same problem regardless of location.

There's something going wrong somewhere; they work just fine for me (FAR, many delta-based designs in both stock and SP+, e.g.: http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread). Maybe Module Manager issues?

Can you give us screenshots of an identical plane with stock vs SP+ deltas? It might confirm whether your problem is restricted to SP+ or is a broader issue.

EDIT: semi ninja'd...

[King_komodo93]

Ah! I think I found it. You've got Firespitter and ModuleManager in double-deep GameData folders: KSP\GameData\GameData\. Try bumping them up a level.

That fixed it thank you. Should've figured that it would be something that silly (silliness being my fault).

[Geschosskopf]

Didn't see this mentioned in the last few pages; in fact quite the opposite, so here goes.

First off, I'm using NEAR (and DRE if that makes a difference).

So anyway, I've seen folks complaining these wings were very low-lift. I have the opposite problem--I can't get my planes to slow down or land when they come down from space. Let's say I've got a plane in a 100km orbit and I do a de-orbit burn over the desert so my blue trajectory line comes down in the ocean just E of KSC. With stock wings, this will make them come down close enough to KSC that I can then fly them to the runway. But not with these SP+ wings. Instead, the plane doesn't even start reentry flames until passing over KSC at about 32km. It will get down to about 25km halfway across the ocean, then start an unstoppable climb until it gets back up to about 40km. Then it starts back down again and the process repeats. Each time it gets a tiny bit lower before going up again. Without using any thrust or touching the controls except to maintain a good reentry AoA, the plane will glide 3/4 of the way around Kerbin. I've also tried trying to force the plane down with pitch and have added control surfaces to use as spoilers (via NEAR) but that doesn't have much effect.

Any ideas what's causing this?

[TheReaper]

SP+ generaly have troubles recognizing correct drag/lift with NEAR, i think porkjet should do a re run of config files, they generaly have lower drag, although they have the reguler lift as they are intented, they usualy end up massive force in pitch down or high wing pressure that plane wont even have to use engines at all. i have never exprienced these problems with FAR or stock though.

[dualmaster]

Didn't see this mentioned in the last few pages; in fact quite the opposite, so here goes.

First off, I'm using NEAR (and DRE if that makes a difference).

So anyway, I've seen folks complaining these wings were very low-lift. I have the opposite problem--I can't get my planes to slow down or land when they come down from space. Let's say I've got a plane in a 100km orbit and I do a de-orbit burn over the desert so my blue trajectory line comes down in the ocean just E of KSC. With stock wings, this will make them come down close enough to KSC that I can then fly them to the runway. But not with these SP+ wings. Instead, the plane doesn't even start reentry flames until passing over KSC at about 32km. It will get down to about 25km halfway across the ocean, then start an unstoppable climb until it gets back up to about 40km. Then it starts back down again and the process repeats. Each time it gets a tiny bit lower before going up again. Without using any thrust or touching the controls except to maintain a good reentry AoA, the plane will glide 3/4 of the way around Kerbin. I've also tried trying to force the plane down with pitch and have added control surfaces to use as spoilers (via NEAR) but that doesn't have much effect.

Any ideas what's causing this?

I'm using FAR+DRE and have experienced the same. If you dive into the atmosphere too quickly you burn up, but if you maintain enough AOA to limit your vertical descent you end up taking forever to slow down. I tried using some S-turns such that keeping an AOA just turns you to the side instead of lifting out of the atmosphere, but even with that it still takes 10-15 minutes to slow down to normal cruising speeds in the lower atmosphere.

Additionally, I have a ton of trouble trying to land. In the lower atmosphere with zero thrust I can barely slow down below 200 m/s. At 1000m and 200 m/s, I'll glide tens of kilometers and still be going 120+ m/s. I can't even flair very hard because modest AOA causes the plane to break up from aerodynamic stresses. The only way I've been able to land a plane is using B9's air flaps to slow me down.

I need to build some planes with B9 or stock parts and see if it is just an issue with SP+ parts.

[Starwaster]

I'm using FAR+DRE and have experienced the same. If you dive into the atmosphere too quickly you burn up, but if you maintain enough AOA to limit your vertical descent you end up taking forever to slow down. I tried using some S-turns such that keeping an AOA just turns you to the side instead of lifting out of the atmosphere, but even with that it still takes 10-15 minutes to slow down to normal cruising speeds in the lower atmosphere.

Additionally, I have a ton of trouble trying to land. In the lower atmosphere with zero thrust I can barely slow down below 200 m/s. At 1000m and 200 m/s, I'll glide tens of kilometers and still be going 120+ m/s. I can't even flair very hard because modest AOA causes the plane to break up from aerodynamic stresses. The only way I've been able to land a plane is using B9's air flaps to slow me down.

I need to build some planes with B9 or stock parts and see if it is just an issue with SP+ parts.

What you're describing sounds about typical of shuttle landings. You're about maybe 20% faster than the shuttle might have been. Also remember that the shuttle had to use air brakes too. What you're lacking that the shuttle had is a drag chute

Real Chute mod has drag chutes. They deploy on touchdown.

Frankly I'd disable the aerodynamic stress feature of FAR. It's overzealous to the point of unrealistic. You SHOULD be able to flare pretty hard when trying to land and anything that stops you from doing that you should ditch.

[TheReaper]

I'm using FAR+DRE and have experienced the same. If you dive into the atmosphere too quickly you burn up, but if you maintain enough AOA to limit your vertical descent you end up taking forever to slow down. I tried using some S-turns such that keeping an AOA just turns you to the side instead of lifting out of the atmosphere, but even with that it still takes 10-15 minutes to slow down to normal cruising speeds in the lower atmosphere.

Additionally, I have a ton of trouble trying to land. In the lower atmosphere with zero thrust I can barely slow down below 200 m/s. At 1000m and 200 m/s, I'll glide tens of kilometers and still be going 120+ m/s. I can't even flair very hard because modest AOA causes the plane to break up from aerodynamic stresses. The only way I've been able to land a plane is using B9's air flaps to slow me down.

I need to build some planes with B9 or stock parts and see if it is just an issue with SP+ parts.

you definitly need b9 airbrakes

[Wanderfound]

I can't even flair very hard because modest AOA causes the plane to break up from aerodynamic stresses. The only way I've been able to land a plane is using B9's air flaps to slow me down.

I need to build some planes with B9 or stock parts and see if it is just an issue with SP+ parts.

Are you strutting your wings? It's pretty much compulsory with FAR, whether you're using stock parts or SP+.

I don't have trouble getting my SP+ planes to land, and they don't pop their wings any more often than my stock planes, but they do seem to take longer to slow during reentry than stock. I think it's just because SP+ parts let me create much sleeker designs; they should be lower drag.

For me, the solution is just to set my descent westwards of where I'd do it in stock. Don't aim straight for KSC, try to get down far enough that you just clear the mountains and then do a series of dive/flare manoeuvres as soon as you get past them. Lined up, low and slow as early as possible is the trick for easy landings.

[TheReaper]

best re entires i ve exprienced are decents that directly ends in the mounterns west of KSC, just above them, get low enough to pass em up close, high enough to not hit em,you will sitll have a couple of kilometers of run down that you can use to make a good landing trajectory.airbrakes are highly recomended

[dualmaster]

Frankly I'd disable the aerodynamic stress feature of FAR. It's overzealous to the point of unrealistic. You SHOULD be able to flare pretty hard when trying to land and anything that stops you from doing that you should ditch.

I expect I'll eventually go to just using NEAR instead of FAR. The extra challenge is good, but in the long run I don't want to deal with accidental disassembly just because I turned a tad too hard.

Are you strutting your wings? It's pretty much compulsory with FAR, whether you're using stock parts or SP+.

I don't have trouble getting my SP+ planes to land, and they don't pop their wings any more often than my stock planes, but they do seem to take longer to slow during reentry than stock. I think it's just because SP+ parts let me create much sleeker designs; they should be lower drag.

For me, the solution is just to set my descent westwards of where I'd do it in stock. Don't aim straight for KSC, try to get down far enough that you just clear the mountains and then do a series of dive/flare manoeuvres as soon as you get past them. Lined up, low and slow as early as possible is the trick for easy landings.

I'll have to try strutting a little heavier. I hate how it looks but I guess the B9 invisible struts aren't too bad.

[Wanderfound]

I expect I'll eventually go to just using NEAR instead of FAR. The extra challenge is good, but in the long run I don't want to deal with accidental disassembly just because I turned a tad too hard.

I'll have to try strutting a little heavier. I hate how it looks but I guess the B9 invisible struts aren't too bad.

Strut from underneath, and start from the wingtip in so you don't get the ugly bit showing out there. A pair of struts per wing piece usually does me; one along the leading edge, one along the trailing edge.

It helps that I prefer streamlined delta-based designs that rarely have more than a few pieces per wing (and that's on the big planes; my small ones use single deltas). Most of the KSP plane designs I see around are massively over-winged, IMO.

See http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1353924&viewfull=1#post1353924 for an example of what works for me.

[Geschosskopf]

SP+ generaly have troubles recognizing correct drag/lift with NEAR, i think porkjet should do a re run of config files, they generaly have lower drag, although they have the reguler lift as they are intented, they usualy end up massive force in pitch down or high wing pressure that plane wont even have to use engines at all. i have never exprienced these problems with FAR or stock though.

In the meantime, any ideas of what I could change myself? I mean, anybody can edit ModuleManager files.

I'm using FAR+DRE and have experienced the same. If you dive into the atmosphere too quickly you burn up, but if you maintain enough AOA to limit your vertical descent you end up taking forever to slow down.

Thanks for the confirmation. I was worried I might have screwed something up on my end.

Additionally, I have a ton of trouble trying to land. In the lower atmosphere with zero thrust I can barely slow down below 200 m/s. At 1000m and 200 m/s, I'll glide tens of kilometers and still be going 120+ m/s. I can't even flair very hard because modest AOA causes the plane to break up from aerodynamic stresses. The only way I've been able to land a plane is using B9's air flaps to slow me down.

[Wanderfound]

Additionally, I have a ton of trouble trying to land. In the lower atmosphere with zero thrust I can barely slow down below 200 m/s. At 1000m and 200 m/s, I'll glide tens of kilometers and still be going 120+ m/s. I can't even flair very hard because modest AOA causes the plane to break up from aerodynamic stresses. The only way I've been able to land a plane is using B9's air flaps to slow me down.

Although it's not ideal (100m/s is closer to the mark), 200m/s is a perfectly survivable landing speed. It's your vertical velocity that you need to control, not the horizontal. Excess horizontal is only a problem if you run out of runway or paddock before your ground-brakes finish doing their thing (and you can help them along with spoilers, RCS, Vernors and, in extreme cases, Sepratrons). Coming on to the strip fast but shallow is usually a better option than trying to bleed off huge amounts of speed over the runway when you need to be concentrating on getting your wheels down gently and level.

The behaviour you're describing all sounds normal to me. You want to get down below 1,000m with the throttle off when you're still at least 10km out. A 40 ton hypersonic spaceplane isn't a Cessna; you can't expect to land it like one.

What sort of angle are you folks thinking of as a "modest AoA", BTW?

[AdmiralTigerclaw]

Never had an issue with FAR's atmospheric stress factor myself. I built an SR-71 that behaved nicely until 400 knots EAS. After that, aerodynamic stresses became dangerous for the structure to perform turns in... Just like the real thing!

That being said, people having trouble using FAR probably are doing two things wrong:

1: Not designing their vehicles right. (IE: Trying to make mutually exclusive aerodynamic principles all fit on the same vehicle.)

2: Not flying their designs as they SHOULD fly them. (IE: Trying to fly a brick like a jet fighter.)

Seriously, flare-dive-flare-dive? NO! What do you think you are? An ace combat pilot?

Use S-curves and gentle banking turns on your final approaches. Long slowdown reentries (shallow/soft reentries) are going to take half Kerbin's orbit. You run into the same problem you get with people who fly a jet fighter simulator for the first time. They get impatient and get too aggressive with routine operations like landing and come in hotter than the collector tower for a solar thermal power plant at three-o-clock on an Arizona summer afternoon. And then they expect the thing to behave nicely when they ask it to suddenly perform like an F-15E at Red Flag?

Use the FAR settings for equivalent airspeed and find your stall speed and critical AoA. Learn to fly your design inside its envelope.

My suggestion is to utilize Knots Equivalent Air Speed. (EAS) It's a measurement that gives you the 'equivalent' speed relationship to the pressure it would receive on the vehicle's flight surfaces at those speeds at sea level. A typical vehicle that has cargo capability and spaceworthiness is probably going to have a safe flight range between 120 knots and 390 knots. With 120 being 'too slow, you gonna stall if you haven't already', and 390+ being 'too fast, something's gonna rip off'. A light single engine prop like you'd see at a small country airport will get off the ground at around 55 knots and fly no faster than 130 knots. High supersonics and flying bricks probably will have the lower limit around 170 to 200 knots for stable flight and gliding. Only combat fightercraft, built for high Gs and heavy wing loading in turns are really meant to do any form of maneuvering above 400 KEAS.

Also remember, 10 and 20 degrees are actually pretty steep dives in the realm of aircraft and you'll maintain insane amounts of speed at these angles. A typical landing descent for an aircraft to an airport is a 3 degree glide slope. In flight in KSP, a descent looks deceptively shallow in the external camera views. I'd suggest navball hud and setting it so you have horizontal lines every ten degrees. (See previously linked video.) Also install the PAPI (Precision Approach Path Indicator) mod so you have a visual indication of your glide slope position. (I think it defaults to 6 degrees, so you might have to tweak its config.) There's an HSI mod floating around too that gives you aircraft ILS markers for approach.

(As a parting shot: Typical flight for an SR-71 airframe: Takeoff 170 KEAS; Low Level Flight with safe turning 250 to 300 KEAS; At Altitude Supersonic Cruise with long, slow [5 minutes +] high mach turns, 300 to 365 KEAS; Landing ~200 KEAS)