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

[NathanKell]

Try being more gentle. If flying with the keyboard, use capslock and "peck peck peck" the keys, don't hold them down.

[TeeGee]

Try being more gentle.

Oh I'm gentle. I tap my pitch angle to correct my course and kablamo! It scares me every time!

I'm not complaining about the mod, I'm just flustered at how flimsy my plane is and I can't seem to make her sturdier. Why didn't my planes do this before?

I've been using ferram for a pretty long time... maybe I was just getting lucky before and now its coming back to bite me in the bum.

[Sparker]

Try not to fly at supersonic speeds so low, lose as much speed as you can higher and then glide down. Also, try not to maneuver much if your speed is close to the speed of sound.

As I can see, you have very small angle of attack during re-entry. Usually planes like yours re-enter with AOA of about 30-40 degrees, producing rather drag than lift.

[TeeGee]

Try not to fly at supersonic speeds so low, lose as much speed as you can higher and then glide down. Also, try not to maneuver much if your speed is close to the speed of sound.

As I can see, you have very small angle of attack during re-entry. Usually planes like yours re-enter with AOA of about 30-40 degrees, producing rather drag than lift.

So you think I should come in harder to lose speed faster? I might try that. I usually do skip reentries..

Edited June 19, 2014 by TeeGee

[SnappingTurtle]

I've found a very high angle of attack on return allows you to level out at about 40km.

[Hodo]

1 word... well really two..

Air brakes.

Slow down before you drop below 10km. I like to be going less than 200m/s when I am landing.

[ferram4]

@Sparker: You've got a wing with a built-in IR hinge as a single, integrated part? First things first, FAR is never going to simulate the sweep properly, since the angle of the part with respect to the air will never change when it animates. Second, of course changing the drag values in the config doesn't change how FAR handles drag, it automatically zeroes those out before trying to handle the part. Third, wings need specially defined config files for them to work properly; documentation is available in the readme or on the Github wiki.

@TeeGee: You see that "high dynamic pressure" warning? That's telling you, maneuvering like a madmen will cause bad things to happen, slow down dammit. Frankly, you're flying at the dynamic pressure limits of a lot of supersonic fighters at those speeds and altitudes, so something as fragile as an SSTO isn't going to fare much better than it already is. More S-turns, more angle of attack higher in atmosphere, more drag, subsonic before you try to drop below the clouds.

[TeeGee]

Yup, that was one of the reasons. The biggest problem was that my landing inclination was off, therefore putting my glide slope to the side of KSC by a few km. That meant I was forced to turn at high speed in thicker air that ripped my wings apart.

1) I need to slow down

2) I need to drop DIRECTLY onto the KSC (like I usually do).

I added airbrakes onto my craft for more control. I realized how fast I was coming in when I was on final, gear down, 200 m from runway and my velocity was still mach 1.2. Yeah, I was coming in waaay too fast and because i was so off course, when I adjusted my heading, the aerodynamic surfaces ripped off everything.

Cooool.

Does anybody know how to perform s turns? I tried doing them in upper atmo but was noticing my heading kept changing so I went back to doing s turns up and down (not left to right). I even managed to slow down to mach 4 but still came in too hot and wings ripped off.

Any good reentry with FAR tutorials?

Edited June 19, 2014 by TeeGee

[NathanKell]

Well yes your heading will change. That's why it's an S curve, not a C curve: you change you heading back again.

[BudgetHedgehog]

Well yes your heading will change. That's why it's an S curve, not a C curve: you change you heading back again.

What he said. I was thinking of something more productive to say, but that's pretty much it - if your heading changes, just turn the other way and change it back. Twice the number of turns, none of the heading change.

[TeeGee]

Well yes your heading will change. That's why it's an S curve, not a C curve: you change you heading back again.

Yeah I know, but without a landing assist (mechjeb or KE) on my ship it's difficult for me to judge whether Im on course by having to constantly jump into the map and back to flying again. I've tried doing navigation purely in map mode but there are some things on my craft that can't tolerate the heat very well and end up burning on reentry, so I try to keep those things out of the flames. I usually have a transponder probe at the site but didn't put one in this save because I forgot to.

[BudgetHedgehog]

Yeah I know, but without a landing assist (mechjeb or KE) on my ship it's difficult for me to judge whether Im on course by having to constantly jump into the map and back to flying again. I've tried doing navigation purely in map mode but there are some things on my craft that can't tolerate the heat very well and end up burning on reentry, so I try to keep those things out of the flames. I usually have a transponder probe at the site but didn't put one in this save because I forgot to.

If you put a craft on the launchpad or runway or whatever, when flying your plane for re-entry, set that as your target. It'll appear on your navball and you can adjust course as needed. Considering how efficient turbojets are, you could be hundreds of kilometres off course and still make it back safe and sound - I recently tried making a new SSTO but when I ignited the rocket to boost into orbit, I spun out. Decided not to go to space today and after an exciting flat spin from 20km, I turned around and headed back - this was about 200km from KSC. Yes, I did use MJ to target the VAB but I could just have easily done the same thing had I had a probe sat on the end of the runway to target instead.

I think the major thing to take away from this is "I usually have a transponder probe at the site but didn't put one in this save because I forgot to." - if that's the case, FAR isn't exactly to blame now, is it...

[Starwaster]

If you put a craft on the launchpad or runway or whatever, when flying your plane for re-entry, set that as your target. It'll appear on your navball and you can adjust course as needed. Considering how efficient turbojets are, you could be hundreds of kilometres off course and still make it back safe and sound - I recently tried making a new SSTO but when I ignited the rocket to boost into orbit, I spun out. Decided not to go to space today and after an exciting flat spin from 20km, I turned around and headed back - this was about 200km from KSC. Yes, I did use MJ to target the VAB but I could just have easily done the same thing had I had a probe sat on the end of the runway to target instead.

I think the major thing to take away from this is "I usually have a transponder probe at the site but didn't put one in this save because I forgot to." - if that's the case, FAR isn't exactly to blame now, is it...

And if you overshoot, there's always the Island Runway. Maybe.

[BudgetHedgehog]

And if you overshoot, there's always the Island Runway. Maybe.

Unfortunately, overshooting the main runway would have had me heading into the mountains. I thought about landing at the island runway but just as I was thinking that, I remembered I had no airbrakes so it would've been a pretty hairy landing.. Thankfully, it made it back safe and sound without incident, landing at a manageable 120m/s, took the second exit on the left and was quietly retired while the crew had some R&R time.

[RoboRay]

You definitely need to slow down a lot more before descending into the lower atmosphere. As soon as you enter the upper fringes of the atmosphere, point the nose 30-40 degrees off to one side of your course and roll the craft into a steep bank. Yes, this will steer you off course. After a while, roll around and steer back in the other direction. If you're heading to KSC, it's not hard to adjust your S-turns so that you're heading in the right direction (aim for the mountains west of KSC). Adjust your pitch angle to keep you high up, 30km+, for as long as necessary to slow down. Ideally, you'll be so slow before reaching 30km that you don't even see any reentry effects.

Likewise, keep making turns and holding the nose up as you descend. Try to go subsonic around 10km.

If you packed a jet engine, making the runway should be no problem at all. Gliding, you do need a little more precision. For unpowered landings, it's safer to arrive high over KSC and spiral downwards, circling the field to get lined up with the runway.

Airbrakes really shouldn't be necessary... during reentry, the bottom of your wings are your airbrakes... just turn the flat side into the wind. I assign a few control surfaces to brakes, but they are mainly intended for helping get stopped on the runway. In-flight usage would be reserved for emergencies.

Edited June 20, 2014 by RoboRay

[Sparker]

ferram4,

no, the hinge isn't integrated in the wing. I have separate wing, hinge attached to it, and a wing attached to the hinge. They work well together.

Any good reentry with FAR tutorials?

I haven't seen any, although you can watch a video of me making some S-turns at crazy speeds on this video:

There's also a good re-entry made by SpecialistBR, but he managed to land Shuttle without S-turns.

http://www.youtube.com/watch?v=yMzzVHOfuSI

[TeeGee]

Yeah I use AJE so getting into orbit with airbreathers is no longer an option. The tactic I used to always use before was to overshoot the runway and nose down when I was getting close to the KSC to produce that extra bit of drag before my pitch up maneuver. I was always afraid of not making the runway with enough speed to maintain lift.

So when I did my retrograde burn, I would reenter and aim for a target just at the tip of beyond the runway using my wings to adjust my lift on the way. Normally I would try to preserve my speed because my landing point was soo close to the runway... maybe I should do my retrograde burn and aim for a peraps that is BEFORE the KSC, and use my wings to bleed off airspeed for lift.

I honestly don't know what I should be doing because gunning for the runway leaves me with super high levels of airspeed in thicker air.

[LameLefty]

Yes, I did use MJ to target the VAB but I could just have easily done the same thing had I had a probe sat on the end of the runway to target instead.

Out of curiosity, if you use MJ, why not use the Spaceplane Guidance module? It not only targets whichever end of the runway is closest, but also gives you an adjustable glideslope indicator. It can also be set to target the Island Airstrip instead of KSC.

[BudgetHedgehog]

Out of curiosity, if you use MJ, why not use the Spaceplane Guidance module?

Because A, MJ is worse than useless in atmo with FAR installed and B, I find flying planes incredibly enjoyable. I did have the Spaceplane Guidance window open to see the distance to KSC, but I couldn't see anyway to only set the runway as the target, just an option to autoland at it.

[softweir]

@TeeGee: Have you tried using the trim controls (Alt+QWEASD) to control your spaceplane at hypersonic speeds? They are slightly tricky because they don't revert to centre so you have to do it yourself, but they are extremely gentle and precise and can make attitude changes at high speed with too much control-surface much easier.

[RoboRay]

Because A, MJ is worse than useless in atmo with FAR installed

The ILS localizer/glideslope information still works fine.

and B, I find flying planes incredibly enjoyable.

You don't have to turn on the autopilot just because you use MechJeb for data displays.

I did have the Spaceplane Guidance window open to see the distance to KSC, but I couldn't see anyway to only set the runway as the target, just an option to autoland at it.

It's the checkbox that says "Show landing Navball guidance." Just click it.

[LameLefty]

Because A, MJ is worse than useless in atmo with FAR installed and B, I find flying planes incredibly enjoyable. I did have the Spaceplane Guidance window open to see the distance to KSC, but I couldn't see anyway to only set the runway as the target, just an option to autoland at it.

Well, Spaceplane Guidance doesn't really DO anything except give you the target/glide slope indicators. You don't have to use the auto land option. It works great, my runway over-run notwithstanding (I landed a bit long, had no parts set for use as airbrakes and couldn't slow down fast enough).

[Drew Kerman]

how do you factor in weight to your design? I'm not talking about a shifting CoM I'm talking overall weight of the entire craft and whether it's just too heavy to get off the ground. Is this factored into the static analysis?

[BudgetHedgehog]

<snip>

Sorry, I wasn't terribly clear - I actually enjoy flying planes by eye. Given the choice between setting an autopilot and flying manually, I'd choose manually every time. I'll turn on info displays but not the autopilot - I don't care for exact targeting or ILS/glideslope info, I much prefer to fly and land it by eyeballing it alone. All I need is a general direction to head in and I can pretty much sort out the rest myself. The whole "MJ is worse than useless" is because I couldn't see an option to just target the runway so it was either fully automated (which didn't work) or nothing (save for the distance to runway). I'll have a look next time I boot up KSP and see if I can find that option but to be honest, I won't mind if I can't. But thanks for the guidance and help, I'll look into it

[RoboRay]

Sorry, I wasn't terribly clear - I actually enjoy flying planes by eye.

I'm a pilot. We use the tools available to us when they improve precision or simply allow operations that otherwise would not be possible (such as staying right in the proper position while descending through a cloud layer). Once you can see the runway to eyeball it, the ILS guidance isn't important anymore. It's really there for when you can't yet see what you're trying to eyeball.