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

[TheXRuler]

If i'm reading the version info correctly, i was using 0.14.1.

The main reason is that once I reach about 700 m/s my SSTO just stopps accelerating, and I also find myself unable to climb any higher.

I was thinking that it must have to do with either lower lift or higher drag, or both, so that may be the problem.

I just dont really want to redesing my entire SSTO series, because, since i don't really have any professional knowledge on how to consrtuct spacecraft, it is a very, very long and tedious process to build a nice SSTO that can carry large payloads to orbit.

[Van Disaster]

That mass shouldn't be beyond the capability of two SABRE Ms, although I suspect it's quite borderline. 700m/s is awfully slow though, what altitude are you managing to get up to?

[bdito]

If i'm reading the version info correctly, i was using 0.14.1.

The main reason is that once I reach about 700 m/s my SSTO just stopps accelerating, and I also find myself unable to climb any higher.

I was thinking that it must have to do with either lower lift or higher drag, or both, so that may be the problem.

I just dont really want to redesing my entire SSTO series, because, since i don't really have any professional knowledge on how to consrtuct spacecraft, it is a very, very long and tedious process to build a nice SSTO that can carry large payloads to orbit.

That's weird. Those engines max out well above 700m/s. I can't see any air intakes. I assume they're under the wings right? Try posting a pic of it in flight when it's maxed out at 700 m/s with all the telemetry info showing.

[Van Disaster]

Feeling a bit stupid atm: I'm trying to balance pairs of spoilers but they're still giving me a pitching moment no matter how much fiddling with deflection I do - which derivative am I meant to be looking at?

[tetryds]

@TheZRuler: there is a bug on the current version, update your craft activating decouplers before taking off.

The bug makes all parts behind intakes behave like if their nodes were exposed, the game needs to verify the craft again to notice they are not.

The latest git version already got that fixed (I think).

[Hodo]

Feeling a bit stupid atm: I'm trying to balance pairs of spoilers but they're still giving me a pitching moment no matter how much fiddling with deflection I do - which derivative am I meant to be looking at?

Where are they located on the craft? Are they inline with the CoM of the vehicle or are they slightly behind it. If they are behind it they are going to act like elevators and pitch the nose up with they are activated. So the trick is to have them alternate on the same wing, one up one down same angle same length.

Unfortunately I don't have a picture currently of this with them deployed but you can see the flaps and the spoilers on the wings.

The flaps are the inner most control surface and the spoilers are the next ones out.

[Van Disaster]

They're pairs of up and down but given they're on a swept trailing edge can't be identical - I can't get the right combination of angles to balance the pitch moment, and I can't apparently work out which derivative to be checking today... I thought it was Mu but that doesn't seem to change in a useful fashion if I twiddle these things.

[HoneyFox]

They're pairs of up and down but given they're on a swept trailing edge can't be identical - I can't get the right combination of angles to balance the pitch moment, and I can't apparently work out which derivative to be checking today... I thought it was Mu but that doesn't seem to change in a useful fashion if I twiddle these things.

You can always watch the Cm curve with Spoiler option on/off to check if the pitch moment variation is minimized if you activate the spoilers.

Edited January 24, 2015 by HoneyFox

[DaMichel]

Moreover you used to be able to set the elevators/canards or any control surface as spoilers, too. The deflection of control inputs and spoiler activation added up. That way you could could balance the torque without additional control surfaces. Haven't tried this in a while. It still works like that for flaps though.

[Goddess Bhavani]

Decided to go all "Ambitious But Rubbish" in my first 0.90 Career Mode (super hard) survey aircraft.

More like a manned cruise missile but it's my first ever (barely) controllable lifting body so I decided to record some of the hilarious epic fails and some stellar successes (like learning how to fly the lifting body without ripping off the stabilizers).

I was surprised the current version of FAR allows for underbody airfoils - in 0.24.2 the underbody wings would act like they had blocked airflow (0 lift 0 drag).

[Toastedbuns]

With Ferram, how would one go about NOT burning to a crisp upon re-entry with Deadly Reentry? I kept blowing up after my Munar mission

[Van Disaster]

Moreover you used to be able to set the elevators/canards or any control surface as spoilers, too. The deflection of control inputs and spoiler activation added up. That way you could could balance the torque without additional control surfaces. Haven't tried this in a while. It still works like that for flaps though.

Does not work with spoilers - they're either spoilers or anything else.

[dimovski]

Could you please tell me how this happened and how I can fix it, because after hours of swearing and .cfg changes I still haven't figured out the problem:

I added a bunch of nodes to a part, to allow side-mounting some fuel tanks which had weird colliders and wouldn't attach properly in any other way, and this happened:

[ferram4]

That would be because FAR currently uses nodes as a quick approximation for figuring out the blunt ends of a part. When you do things like add a ton of unused nodes everywhere or clip parts in ways that mess with the nodes, FAR does things wrong.

Get rid of the nodes and do the surface attach right (if your colliders are messed up, you're gonna have a bad time anyway), or say that you're not supporting FAR until I get the better code implemented.

[Hodo]

With Ferram, how would one go about NOT burning to a crisp upon re-entry with Deadly Reentry? I kept blowing up after my Munar mission

At what altitude are you performing your de-orbit burn?

Are you using air brakes to slow down at above 30km?

What is your PE after you perform your de-orbital burn?

These are important bits of information.

I use DRE and FAR and the trick is to have an AP of 100km and a PE of around 5-10km. You should be going less than mach 6 before you drop below 25km ASL.

[lolstock]

Hey so I've been having an issue where I get really low FPS for 30 seconds or so and then jump to higher than normal FPS for a little bit. and then back down to somewhere in between those. It seems to fix itself when I remove FAR (all others are removed) but IDK I could just be going crazy.

[tetryds]

@lolstock: does that happen to other games too?

To me it sounds like you are having overheating issues.

[lolstock]

I might be. It's a vaio pro so it's not exactly a gaming setup haha. Any advice on what to do about that?

[TheXRuler]

Thanks a ton in advance, I will try doing that as soon as i am back at my PC. What exactly do you mean by activating decouplers before takeoff? Like put in some random decouplers to activate before starting up the engines? I do normally launch the plane using two solid rockets for additional acceleration on the runway, these are obviously decoupled once they burn out, which happens to be exactly at the end of the runway. So in a way i do activate one pair of decouolers upon liftoff, not beforehand though.

[TheXRuler]

That's weird. Those engines max out well above 700m/s. I can't see any air intakes. I assume they're under the wings right? Try posting a pic of it in flight when it's maxed out at 700 m/s with all the telemetry info showing.

Intakes are half above and half below the wings, once i get home I'll post some better pics. If you look closely you can just make them out in the second screenshot, between the wing and the cargo bay doors.

[tetryds]

@TheXRuler: yes, pretty much.

Well that is strange, high altitude supersonic drag is higher now but it shouldn't be that bad.

Turn on the Cd display and check if there isn't anything fancy going on.

[Toastedbuns]

I had an extremely high apoapsis so I just did several high atmosphere burns at abt. 40K altitude to lower it, and eventually I landed in the ocean.

[TheXRuler]

Ok thanks, I'll get the newest version and try the decoupler thing, do some more extensive testing at high altitude and with the Cd display on. I'll upload a bunch of new screenshots to. I did try the Cd dispay once, and it all looked relativley evenly spaced out. Could it really just be that with the added high altitude drag it is no longer feasible to launch a 300 ton SSTO on two Sabre Ms?

Edited January 25, 2015 by TheXRuler

[tetryds]

Well, that depends on the design, but it's possible.

This could also be a shielding issue, try opening then closong the cargo bay.

If there are no bugs I recommend making a new one.

[Van Disaster]

Ok thanks, I'll get the newest version and try the decoupler thing, do some more extensive testing at high altitude and with the Cd display on. I'll upload a bunch of new screenshots to. I did try the Cd dispay once, and it all looked relativley evenly spaced out. Could it really just be that with the added high altitude drag it is no longer feasible to launch a 300 ton SSTO on two Sabre Ms?

While I was flight testing a revised version of my heavy lifter I thought I'd try this, so I turned two of the engines off. After 1h 45 or so, most of which was clawing it's way from 15km to 30km with a 0.24 twr ( launch mass was ~360t ) it made it to a 90km circular orbit so it's still easily possible. That is a craft designed for four engines ( and a completely experimental craft designed for wing research too ). I don't think I'd have tried 300t with two engines even in builds for 0.25 ( my two engined craft were nearer 200t-ish ) but it's not the high speed drag doing it. This craft's cD was very low until ~mach 4.5 or so even with a high AoA.