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

[DaMichel]

Yeah, these things actually help even if just a bit. Btw. i think a deployed landing gear now generates more drag than in previous versions of FAR. Or it is just my imagination, IDK.

[DivisionByZero]

@DivisionByZero:

Thanks a lot, your guide was very helpful, it turns out it was a dynamic stability issue which I could solve very quickly with the help of the simulation.

I still don't understand exactly what was happening but now it's fine, and after I finish reading the wiki maybe I will have an idea about what was happening.

This will be very very useful in future designs.

I was going to recommend for this to be linked from the first page but I see that it already is a link to the wiki but I didn't saw it before...

Do you know what phi (Φ) is in lateral simulation? I think that it might be some lateral (angular?) speed but I am not sure.

I'm glad it helped!

Hmmm.... if it's not described in the tool-tip when you hover over the entry I'm not sure I'll be able to tell you. Off the top of my head I can't recall a phi. I'll try to remember to look for it next time I start-up the game.

[Sparker]

Is it possible to make a yaw control surface that splits into two parts and acts as an air brake like on Space Shuttle and Buran? Well, I've made it by adding two control surfaces to one vertical stabiliser in simmetry mode and both setting 'Yaw' and 'Spoiler' options, but sometimes it works great and sometimes it deflects both of them to one side. Maybe I could place two control surfaces separately, but it can lead to instability during high speed flight.

Yeah, these things actually help even if just a bit. Btw. i think a deployed landing gear now generates more drag than in previous versions of FAR. Or it is just my imagination, IDK.

I've also noticed that, at least with B9 landing gear.

[Taverius]

Notable design changes compared to the small version include a larger wing area to support the additional weight and a larger vertical tail since it was a bit too twitchy. Oh and i angled the large wing part a little bit upward to help generate lift for take off.

Point the SABRE intakes down, not to opposite sides.

That's how we designed them to work, and yes it makes a difference - the intake vector is not straight, but angled to give max intake efficiency at a slight pitch-up AoA.

[DaMichel]

You have good eyes Taverius, thanks They were supposed to be pointing down. It's just that they happened to rotate this way without me noticing when i enlarged the engine nacelle.

P.S.: *whisper* here is a secret: there is another pair of intakes on the underside, which, while not required, result in quite some fuel savings on the trip into orbit.

Edited June 16, 2014 by DaMichel

[Alshain]

Well, I'm still having issue with getting my planes to go down the runway straight. I don't understand it really. Is there anything I can change that will keep it from pulling to one side? In the rare case I manage keep it from crashing in the grass long enough to get in the air, it works fine... taking off from the grass. But since the stupid runway is on a hill that rarely occurs. Right now I do have 1 solution, delete this mod.

[BudgetHedgehog]

Are you sure it's FAR?

You're using B9 wheels, presumably - have you done the fix for them? Also, the game has a bug where parts applied in symmetry (and when not) will not be treated equally - this includes wheels and wings. Also, are you sure your wheels are on straight? Where are they placed? If too far apart or too close together, you'll be unstable.

[Alshain]

They are straight as I can get them. I have done the B9 patches. I even tried replicating

and couldn't get it off the ground. Sorry, I wanted a challenge, not to beat my head against a brick wall. I deleted it.

[NathanKell]

Use Snjo's gear alignment module to display gear axis alignment vs. straight, and use Padishar's Part Angle Display to rotate them (in fractions of a degree) until straight.

[Drew Kerman]

can't wait until Snjo gets this out...

[Alshain]

Ok, I owe you guys an apology. I decided to restore it and give it one more go... the wheels weren't straight. I moved them just a slight tiny little bit and managed to get it up and away. But it is weird that the same plane worked fine in the stock aero package. I wouldn't think wheels on the ground would change with FAR.

[Drew Kerman]

The different lift generated with FAR vs stock would most likely cause a different compression on the wheels to create a different interaction with the ground

[scul]

I found a glitch in FAR with how it handles drag on the linear RCS port. The following images have just FAR and Kerbal Engineer (both are the most up to date versions) installed on a fresh install of 0.23.5 for this test. First picture is with the RCS port on the base, second is with out. Note the Cd in both pictures (0.005 vs 0.158). Craft are also simplified for this test down from what I discovered it with.

Both these craft were put into about 10,000km x 15km orbit, and are identical other than the single RCS port. Video of both re-entries will be available once it renders and uploads.

Edited June 19, 2014 by scul

[ferram4]

That's not the linear RCS that's screwing up, it's the RCS tank that is messing up. It's similar to the errors where attaching a tiny nosecone to the top of a wide rocket reduces drag significantly, and there are currently no known fixes that don't also lag the game to hell.

[scul]

Gotcha, thanks.

[Sparker]

How can I switch off drag and lift for specific part?

I've got a wing with built-in Infernal Robotics hinge and it spoils aerodynamics. I nulled the 'minimumdrag' and 'maximumdrag' attributes in the .cfg file of the part, but they still produce drag.

Thanks!

[AndreyATGB]

How can I switch off drag and lift for specific part?

I've got a wing with built-in Infernal Robotics hinge and it spoils aerodynamics. I nulled the 'minimumdrag' and 'maximumdrag' attributes in the .cfg file of the part, but they still produce drag.

Thanks!

I think the new debug/cheat options from the space center view can do this. I haven't used them, but they are an easy way to change settings without manually editing all the cfg's.

[TeeGee]

Everytime I tap my elevons during reentry or at any speed over mach 1, my wings rip off due to "excess G's". It only happens on my latest ssto and I don't know why. I even reinfoced them with struts, still didn't help. I thought I had it corrected and when I was on approach to land in my ssto, my wings tore off and killed 5 kerbals... =(

Sad.

I don't use sabre or rapier engines since they haven't been invented in RL yet, my ssto is using a rocket as its main engine.

She survives reentry, makes course corrections etc, but when she nears KSC she breaks her wings at even the slightest tap.

Edited June 19, 2014 by TeeGee

[Hodo]

Everytime I tap my elevons during reentry or at any speed over mach 1, my wings rip off due to "excess G's". It only happens on my latest ssto and I don't know why. I even reinfoced them with struts, still didn't help. I thought I had it corrected and when I was on approach to land in my ssto, my wings tore off and killed 5 kerbals... =(

Sad.

I don't use sabre or rapier engines since they haven't been invented in RL yet, my ssto is using a rocket as its main engine.

http://i.imgur.com/czu82FZ.png

First off cant see the craft in your post...

Now that I have seen it....

Your control surfaces are HUGE for that aircraft, try reducing the control angle of the control surfaces first, and second you may want to slowdown a LOT more before thinking about using them. Right now it is like sticking a billboard into tornado when you try and use them.

[orost]

Does FAR understand propellers?

I installed FAR with KAX and noticed that my planes are suffering from very poor top speeds and dive characteristics - a fairly sleek 4.5 ton design with the 120kN radial won't break 130 m/s in level flight and 150 in a 60 deg dive. FAR thinking the propeller disc is a solid surface and putting very high drag on it would explain that.

[TeeGee]

First off cant see the craft in your post...

http://i.imgur.com/czu82FZ.png

Now that I have seen it....

Your control surfaces are HUGE for that aircraft, try reducing the control angle of the control surfaces first, and second you may want to slowdown a LOT more before thinking about using them. Right now it is like sticking a billboard into tornado when you try and use them.

Right but when I need pitch authority, this craft doesn't perform how I want to. Usually when I approach the runway I perform the pitch up maneuver when I am practically on top of the runway to bleed off excess speed. Because my center of lift is soo far behind the com, that is very difficult unless I use larger elevons.

[RoboRay]

Because my center of lift is soo far behind the com, that is very difficult unless I use larger elevons.

The solution is to address your CoL/CoM relationship, not attempt to work around the problem with oversized and overextended control surfaces. Can you post some VAB shots showing the markers, with both full tanks and empty? Maybe we can offer some specific suggestions.

[TeeGee]

Sure can! The problem is 2 fold:

1) I like good response craft with great cross range during reentry.

2) I am looking for a certain "look". I generally don't like to add canards.

[RoboRay]

I am looking for a certain "look". I generally don't like to add canards.

You may not need them, but they would probably be the simplest solution. It might be enough to just have more of a delta-wing shape, with wider wing-roots and the leading edge sweeping back at a greater angle.

[TeeGee]

It happened AGAIN! No casualities this time, use probe core. Look at how close I get and how slow I am going... I even smeared struts on her just to prove the point.