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

[BigNose]

Saw some of you trying to get to Mach 2 with a single basic jet engine, thought I would slap one on my F-104G Starfighter replica (Luftwaffe version) and give it a shot. It normaly uses a a BDynamics Vector jet (gimbal off) limited to 78.5% thrust for realistic performance and TWR. The real F-104 was limited to fly Mach 2 not because of it's aerodynamics (in theory it could have flown much faster), but because its engine's compressor wasn't up for it and overheated at around Mach 2.1! So there was a warning in the cockpit which lit up (the word: SLOW) to get the pilot to pull the throttle back, otherwise engine explosion.

The basic jet engine is a bit too weak for the task (unrealisticly weak for my starfighter replica), I could barely touch Mach 1.968.

NOTE: This F-104 wasn't built for minimal wave drag but to be a good replica. Interestingly enough, with the BDynamics engine it pretty much flys exactly like one (according the the specifications I got from a real manual of a Starfighter).

[balu0]

So nice to see a replica performing realistically

[ferram4]

@bagofholding & Neuntausend: I did find a possible race / deadlock in the vessel voxelization code, and it should be fixed in the current dev build. Try that, and see if you can reproduce it. In any case, if it's that, I think I might have fixed it, so I'll consider this closed unless someone can reproduce on the dev build.

@Kitspace: Yes, it will default to the middle at neutral. As I said, adding code to adjust that would mean adding more sliders to the bloated tweakables menu, so not unless I do something like implement the B9 tweakables method instead.

Never flown a plane at very low altitude at very high Mach number on a plane that displayed raw IAS, have you? Most planes that can fly fast enough to hit those effects automatically go for EAS to avoid confusion.

Also, wikipedia is correct... for incompressible flow. They're actually talking about total pressure, technically, which is equal to stagnation pressure for Mach = 0, but is lower than stagnation pressure for all Mach > 0. This is unfortunately how wikipedia operates; incorrect information because the people that can follow wikipedia's red tape are only competent at following the red tape, not with what they're describing. God knows if it's even possible to get that fixed.

Most aerodynamics textbooks will cover the difference correctly.

@Sterbehilfe: No idea why you're telling me, FAR doesn't touch engine thrust, fuel consumption, or the throttle at all.

[Sterbehilfe]

But do i know that? I'm an end user here as far i know the AoA or DPCP stabilizers throttle back when im flying wrong. But good to know. I found 2 more wrongs with my plane by myself ... the CoM was excentric in regards to the rocket engines, and its possible my "throttling down" happens because of low power. But wait, engines in KSP work without power .... i just dont know.

On the up side, i managed my first reentry without tearing the plane apart.

[balu0]

@bagofholding & Neuntausend: I did find a possible race / deadlock in the vessel voxelization code, and it should be fixed in the current dev build. Try that, and see if you can reproduce it. In any case, if it's that, I think I might have fixed it, so I'll consider this closed unless someone can reproduce on the dev build.

@Kitspace: Yes, it will default to the middle at neutral. As I said, adding code to adjust that would mean adding more sliders to the bloated tweakables menu, so not unless I do something like implement the B9 tweakables method instead.

Never flown a plane at very low altitude at very high Mach number on a plane that displayed raw IAS, have you? Most planes that can fly fast enough to hit those effects automatically go for EAS to avoid confusion.

Also, wikipedia is correct... for incompressible flow. They're actually talking about total pressure, technically, which is equal to stagnation pressure for Mach = 0, but is lower than stagnation pressure for all Mach > 0. This is unfortunately how wikipedia operates; incorrect information because the people that can follow wikipedia's red tape are only competent at following the red tape, not with what they're describing. God knows if it's even possible to get that fixed.

Most aerodynamics textbooks will cover the difference correctly.

@Sterbehilfe: No idea why you're telling me, FAR doesn't touch engine thrust, fuel consumption, or the throttle at all.

ferram4: Your answer to Kitspace interests me greatly. I know about the sub sonic stuff and aerodynamics for small aircraft, gliders and stuff, and I always thought that TAS > IAS is an iron rule and always true (expect that wacky stuff that flying under sea level ) But I can see the logic behind the compressibility stuff, but I'm not familiar enough with that and my only info source was wiki. Could you plz direct me towards a good source , book or link that explains this stuff ? What I found on the net so far is only basic stuff in sub-sonic ranges. And here we want to go fast

[Hektos]

You could add a structural part in the middle to extend the fuselage of the aircraft which would help with that smoothing. Right now your craft is VERY short in length. I took this old design of mine and brought it back for this version of FAR.

The Akula as I called it, is a Mig-21 knock off and it works surprisingly well even now in NuFAR.

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

The reason it does well is because it is pretty long, not as long as most of my aircraft but longer than yours is. It is a bit longer now that I have replaced the center inline intake with a precooler.

Thanks for the tips. I think I'm just really into the mindset of short planes for some reason. Feels so weird to have a long skinny plane with barely any wing

[Hodo]

Thanks for the tips. I think I'm just really into the mindset of short planes for some reason. Feels so weird to have a long skinny plane with barely any wing

You don't have to go all F-104 Starfighter with a plane and go manned missile but you can go with a bit longer craft with a bit less wing to get more performance out of it.

[BigNose]

You don't have to go all F-104 Starfighter with a plane and go manned missile [...]

You just have to stay above 600 knots, then it performs brilliantly!

[Hodo]

You just have to stay above 600 knots, then it performs brilliantly!

LOL its almost like the F-15E Strike Eagle pilots guide to dogfighting. The F-15E is great at 450kts to about 600kts, but a school bus at anything slower than that.

I honestly loved the F-104 as a kid it looked like a futuristic fighter. Then I saw my first F-15C Eagle and I was hooked, if it hadn't been for my eyes going bad I would have been an Eagle driver.

[FourGreenFields]

@ferram: Sorry if you just didnt bother telling me, but did you get the link for the vehicle file?

I am worried I might have ninja'ed you there.

[B15HOP_xmen]

Once again, everyone say it with me, post the output log. Just telling me, "something borke!" with no context basically tells me... nothing. I have no way to fix this.

And honestly, at this point you're hurting yourselves and everyone else. I have bugfixes for things that I would like to release, but I can't with show-stopping bugs around. And if people don't provide logs and full, absolute, completely, start-from-scratch-this-will-always-cause-the-bug reproduction steps, I can't close any of these issues and until they're closed, I can't release bugfixes.

Seriously, this thread is starting to get bug reports with quality comparable to the MJ thread. You people are better than that, act it.

For future reference, where is the output log. No bugs but I play KSP enough to possibly find them. I might do a fresh KSP steam install soon with just KSP + Ferram + Engineer redux and proc parts.

[Guest]

Trying to make a mini fighter lol

[B15HOP_xmen]

For those complaining about loosing yaw authority in high altitude and high mach numbers, I want to share an excerpt from the book: Facing the Heat Barrier: A History of Hypersonics, T. A. Heppenheimer, page 74:

"To steer the aircraft while in flight, the X-15 mounted aerodynamic controls. These retained effectiveness at altitudes well below 100,000 feet (30.48 km). However, they lost effectiveness between 90,000 and 100,000 feet. The X-15 therefore incorporated reaction controls, which were small thrusters fueled with hydrogen peroxide. Nose-mounted units controlled pitch and yaw. Other units, set near the wingtips, gave control of roll"

Also a comment from the pilot during high altitude flight:

"During a flight in September of that year (1956), the test pilot Iven Kincheloe took it (the X-15 aircraft) to 126,200 feet. At that altitude, its aerodynamic controls were useless. Kincheloe flew a ballistic arc, experiencing near-weightlessness for close to a minute. His airplane banked to the left, but he did not try to counter this movement, for he knew that his X-2 could easily go into a deadly tumble"

That X-15 was very experimental to me. I also have quite a lot of reaction control. Once I hit 15km I usually switch RCS on. Some planes are naturally stable even up around 20km altitude in kerbal. I realise Kerbal has a different atmosphere to reality so the air drops off sooner but it is just a game. Otherwise we would have to launch from an earth sized planet with earth sized atmosphere.

[Kitspace]

Ferram4

Balu0

I thought that true airspeed is always higher than indicated airspeed too and as mentioned before never seen otherwise.

Yes I did not fly any kinds of supersonic planes and did not fly high speed planes at extremely low altitudes.

Probably you are right under these conditions. But I guess these effects are in range of a few percent of the speed because the instruments are generally calibrated to be precise. As you said already any significant disruption of accuracy is usually accounted for in the design of the instrument.

What I see in game is still wrong though. It is different from the effect described.

For example the plane is taxiing around the airfield. The groundspeed shown is around ten knots. At the same time the indicated airspeed shown is fifteen knots. That is a fifty percent difference. The speed is obviously too low to cause any aerodynamic effects. As you guess most real life airspeed indicators will not even work at this speed.

After takeoff the very same thing keeps happening with two hundred knots of groundspeed being shown as over three hundred knots of airspeed. And here comes the most interesting part. The indicated airspeed does not seem to be decreasing much with altitude as the plane climbs.

Also the equivalent airspeed looks equal to the indicated airspeed pretty much all the time.

Repeating all the same strange behaviour.

I can make some pictures or a video of what is happening if you need it.

Maybe that is a bug and maybe a reinstall would fix it or something like that.

[Coga19000]

I'm sure I already know the answer, but now that KSP has its own new aerodynamics, what does this mod add?

[blowfish]

I'm sure I already know the answer, but now that KSP has its own new aerodynamics, what does this mod add?

It's all in the OP.

[Hektos]

Nope, not wings, these are procedural structural and tank parts. So PP with B9 or PW and you are almost there ;']

Hey I grabbed these and they definitely seem like they will be helpful for making awesome jets/planes, thanks!

Do you (or anyone else) have any great mods/part packs that go great with nuFar? So far I have PP, the PW(from B9) and just grabbed Bahamuto's engines.

[MarvinCZ]

Some planes are naturally stable even up around 20km altitude in kerbal.

The X-15 quote was about losing control authority from control surfaces, not about stability.

[balu0]

Ferram4

Balu0

I thought that true airspeed is always higher than indicated airspeed too and as mentioned before never seen otherwise.

Yes I did not fly any kinds of supersonic planes and did not fly high speed planes at extremely low altitudes.

Probably you are right under these conditions. But I guess these effects are in range of a few percent of the speed because the instruments are generally calibrated to be precise. As you said already any significant disruption of accuracy is usually accounted for in the design of the instrument.

What I see in game is still wrong though. It is different from the effect described.

For example the plane is taxiing around the airfield. The groundspeed shown is around ten knots. At the same time the indicated airspeed shown is fifteen knots. That is a fifty percent difference. The speed is obviously too low to cause any aerodynamic effects. As you guess most real life airspeed indicators will not even work at this speed.

After takeoff the very same thing keeps happening with two hundred knots of groundspeed being shown as over three hundred knots of airspeed. And here comes the most interesting part. The indicated airspeed does not seem to be decreasing much with altitude as the plane climbs.

Also the equivalent airspeed looks equal to the indicated airspeed pretty much all the time.

Repeating all the same strange behaviour.

I can make some pictures or a video of what is happening if you need it.

Maybe that is a bug and maybe a reinstall would fix it or something like that.

I just checked it wit ha rover , IAS is bigger then Surface speed! But Surface speed is not TAS. What is surface speed in ksp ? ground speed + vertical speed right ? so I m a confused a bit still but I think there is a logical explanation.

[Gfurst]

Guys, @Ferram and moderators

Don't you seriously consider making some additional threads, like for example one for craft design and help, for all people to post their cool designs and ask for help about it.

Maybe another one for development purposes, exclusively for bug reports and issues. And this one for balancing or trouble with the actual mod (or maybe the bug reports too).

Don't you think that be helpful? currently this thread spirals out of control with several posts per hour. Its hard for me to shuffle to whats important or not, imagine you, who actually needs to find whats important.

[futrtrubl]

Hey I grabbed these and they definitely seem like they will be helpful for making awesome jets/planes, thanks!

Do you (or anyone else) have any great mods/part packs that go great with nuFar? So far I have PP, the PW(from B9) and just grabbed Bahamuto's engines.

Adjustable Landing Gear... maybe something with more cockpits... Better Buoyancy for when things go wrong ;']... navHUD, for a glorious HUD... Aviation or Surface Lights if you are into planes... if so then Pilot Assistant too... for rockets Procedural Fairings are so much nicer than stock ;']

- - - Updated - - -

Guys, @Ferram and moderators

Don't you seriously consider making some additional threads, like for example one for craft design and help, for all people to post their cool designs and ask for help about it.

Maybe another one for development purposes, exclusively for bug reports and issues. And this one for balancing or trouble with the actual mod (or maybe the bug reports too).

Don't you think that be helpful? currently this thread spirals out of control with several posts per hour. Its hard for me to shuffle to whats important or not, imagine you, who actually needs to find whats important.

Even with that you would still get posts in the wrong threads and Ferram would have to then go between all the threads. Dev posts already should go to github and not here anyway.

[Amram]

I'm sure I already know the answer, but now that KSP has its own new aerodynamics, what does this mod add?

answer

[NathanKell]

Gfurst that is an excellent idea.

futrtrubl: Just because one can't completely solve a problem isn't a reason not to partially solve it.

[tetryds]

@Gfurst: Very true.

Thus, I created the Official FAR Craft Repository: http://forum.kerbalspaceprogram.com/threads/121176

[tempsgk]

Is there a way to permanently turn off allowStructuralFailures ?

Currently I have to turn it off every time I load into a save game. Would be great if it just saved, and thus defaults to off.