[0.90]NEAR: A Simpler Aerodynamics Model v1.3.1 12/16/14

[ferram4]

Nope, that's correct behavior. Welcome to not-souposphere aerodynamics.

[chrisl]

Then how do you actually land because with basically no drag, my capsule never slows down enough to be able to use my chutes. And being able to put a capsule into space (though not into orbit) with less then 1500 dV seems off.

[tetryds]

Then how do you actually land because with basically no drag, my capsule never slows down enough to be able to use my chutes. And being able to put a capsule into space (though not into orbit) with less then 1500 dV seems off.

You need to set your reentry angle right for that.

If you are not using DeadlyReentry, aiming for a 28km PE will work on most of cases.

And always make sure you have a bit of fuel for some extra breaking if your vessel is heavy.

[sreinmann]

Ok, sorry in advance for posting a question that has been addressed 1,000 times already, but here goes.

I'm new to SSTO designs. I've researched and practiced several posted craft in posted configs but I can't get to orbit. I'm wondering if Maybe my ascent profile is wrong because of NEAR/deadly reentry and I havent found a tried and tested profile like there is for rockets. Can anyone point me to what I'm not seeing?

My design features turbo jets and the smallest 1.25m rockets. I get up to 27,000' and lose air and flame out. Or if I angle down to keep below the service ceiling, I get reentry effects and lose control.

[Crzyrndm]

My design features turbo jets and the smallest 1.25m rockets. I get up to 27,000' and lose air and flame out. Or if I angle down to keep below the service ceiling, I get reentry effects and lose control.

Keep the jets from flaming out until you are doing atleast 1500-1600 m/s (unless using B9 or AJE, both of which heavily reduce jet capabilities). Jets basically run on fumes, so the faster you can go before needing the rockets, the better off you will be. I try and sit close to the flameout ceiling and just fly level until speed caps out (you can move up a bit as you speed up, but not a huge amount). Light the rockets and slowly pitch up (unless you have some serious control authority, upper atmosphere is really good and making planes lose control at 1.5+km/s), don't immediaely close the intakes (action group) the acceleration on rockets can give them a little more life (but remember to shgut them down when they do die), burn till apo leaves atmosphere and then follow prograde with the nose of the craft to reduce drag. Circularise as normal.

If you have a good ascent profile, by the time your jets start spluttering you wil already be at the right speed for rockets, otherwise just flatten off and wait.

[TheReaper]

Question:

when i use this mod all my intakes show 0 drag. This mod also messes with vanilla game's CoL indicator in hangar which i learned is normal. Does the game falsely show 0 drag in intakes like false info it gives on CoL indicator or my drag is really 0? i dont really know, my planes do go off a bit fast but i think that would be normal becouse this mod thins the air a bit so you wont feel like you are swimming in air. I dont know what is true and what is not anymore in aerodynamics. pls help

EDIT: FERRAM has the same problem as well.

Edited December 29, 2014 by TheReaper

[sashan]

Found out that you actually need TWR on jets of .75 for spaceplanes. Climb is a bit slow, but it's enough to reach 1300 m/s speed. Then, I use nuclear aerospike from one mod to go further. It gives .90 twr and 600s Isp.

This is the older version of that plane, still purely on RAPIER engines. Flies like charm. Center of gravity is around the center of cargo bay.

Edited December 28, 2014 by sashan

[chrisl]

You need to set your reentry angle right for that.

If you are not using DeadlyReentry, aiming for a 28km PE will work on most of cases.

And always make sure you have a bit of fuel for some extra breaking if your vessel is heavy.

And what if you are using Deadly Reentry?

EDIT: I'm also still interested in why getting at least 95km sub-orbital flight from just the RT-10 SRB is doable. I love most of the stuff NEAR is offering but being able to make orbit with basically just "Basic Rocketry" (and then only because you don't get a decoupler until you buy your first research level) seems like all the difficulty of space flight is gone. No more spending time gathering science because you can get into a stable orbit with basically starting parts.

Edited December 31, 2014 by chrisl

[LameLefty]

And what if you are using Deadly Reentry?

I'm not but if I was ...

Create a new Sandbox save and test - you'll figure it out pretty quickly.

[Thahat]

well it kinda depends what you are doing. if you build really, really light SSTO's all you need to do is go to around 20.000, and keep it level to you go over 1400M/s, then two of those tiny orange 30KN engines are enough to orbit you. if you like clipping or have other nuclear small parts you can even use those to keep much, much more delta V left after a 100KM orbit.

heavier SSTO's are not my forte though, so i cant say about those. all i know is dont go over 23KM high unless you have a .... ton of airhogging going on.

[luxyuz]

I had to uninstal this mod because mechjeb in atmosphere was useless. It would give me erratic behaviour resulting in loss of control.

Uninstalled the mod and it works great now. Sadly cuz I loved it.

[eldiabs]

Thank you for this mod (and all of the others you have made!). Works great with the slew of mods I have installed, including mechjeb. After much trial and error, I came to realize it was not mechjeb or NEAR causing instability issues, but the builds of my rockets. Happy New Year!

[luxyuz]

Thank you for this mod (and all of the others you have made!). Works great with the slew of mods I have installed, including mechjeb. After much trial and error, I came to realize it was not mechjeb or NEAR causing instability issues, but the builds of my rockets. Happy New Year!

It buggers me how you got it to work. Why all my rockets fly great with or without NEAR, but I just can't use Mechjeb in atmosphere flight with NEAR installed??

Planes shake violently and rockets start wobbling and eventually lose control.

Better Buoyancy on the other end is working great for me, could ditch a plane at very low speeds and nothing break or behaved strange.

Edited January 1, 2015 by luxyuz

[smjjames]

I had to uninstal this mod because mechjeb in atmosphere was useless. It would give me erratic behaviour resulting in loss of control.

Uninstalled the mod and it works great now. Sadly cuz I loved it.

I haven't had any problems with it. Have you tried limiting angle of attack?

I also like it, saves a heck of a lot on fuel for one, except I'm kind of having two problems:

1. MechJeb doesn't recognize the terminal velocity and lets the rocket go right through without even trying to lower the throttle.

2. Landing in atmosphere doesn't seem very precise with NEAR, I tried to get it to land at the VAB and the KSC launchpad, but it keeps going at least a kilometer off target, same with targeted landings elsewhere. It actually seems to work better without a landing engine, but even then, it was still over a kilometer off target.

[Tex_NL]

I had to uninstal this mod because mechjeb in atmosphere was useless. It would give me erratic behaviour resulting in loss of control.

Uninstalled the mod and it works great now. Sadly cuz I loved it.

I haven't had any problems with it. Have you tried limiting angle of attack?

I also like it, saves a heck of a lot on fuel for one, except I'm kind of having two problems:

1. MechJeb doesn't recognize the terminal velocity and lets the rocket go right through without even trying to lower the throttle.

2. Landing in atmosphere doesn't seem very precise with NEAR, I tried to get it to land at the VAB and the KSC launchpad, but it keeps going at least a kilometer off target, same with targeted landings elsewhere. It actually seems to work better without a landing engine, but even then, it was still over a kilometer off target.

The fact MechJeb and FAR/NEAR aren't playing nice together has absolutely nothing to do with FAR/NEAR and everything with MechJeb. Sarbian did release some optional modules to improve MechJeb but it's still hit and miss.

To get good results with MechJebs ascent guidance start your gravity turn as low as possible and set your max acceleration to 1.7/1.8. Once you're above 25/30 km remove the acceleration limit.

[smjjames]

I just do rockets though, haven't played around with spaceplanes, or planes.

As for setting the gravity turn as low as possible, you mean setting the automatic altitude turn in the ascent editor all the way to the left? Just checking.

I'll also check out that optional module.

Edit: I tried to limit the acceleration of the rocket to 1.8 m/s, it couldn't even lift off Maybe you were talking about spaceplanes?

Edited January 1, 2015 by smjjames

[Tex_NL]

My bad. I meant to say 17/18 m/s² which will result in a 1.7/1.8 G. I got the two mixed up.

And yes, slide the 'automatic altitude turn' all the way to the left to 691m. I prefer to keep the 'turn shape' at the default 40%.

[smjjames]

The ascent seems to work better, yes, although the landing stuff in atmosphere is off target by a few kilometers still.

[Commissar]

i cannot for the life of me, build a stable spaceplane in NEAR... i was able to do it previously in FAR, but without the stability diagnostic, it's entirely blind trial-and-error... i thought that NEAR was supposed to be a bit easier?

i would just use FAR, but that introduces aerodynamic dissasembly, which causes problems when i have a rocket entering the atmosphere at mach 7...

[tetryds]

i cannot for the life of me, build a stable spaceplane in NEAR... i was able to do it previously in FAR, but without the stability diagnostic, it's entirely blind trial-and-error... i thought that NEAR was supposed to be a bit easier?

i would just use FAR, but that introduces aerodynamic dissasembly, which causes problems when i have a rocket entering the atmosphere at mach 7...

You can disable that in the options

Try the FAR button which shows up on the KSC view.

Also, no, FAR is easier.

[Commissar]

You can disable that in the options

Try the FAR button which shows up on the KSC view.

Also, no, FAR is easier.

okay, how do i get to the options then?

[smjjames]

Question for you guys, is it easier to build and fly a rocket with NEAR or with FAR? MechJebs landing function is off the mark by kilometers with NEAR though.

[Commissar]

Question for you guys, is it easier to build and fly a rocket with NEAR or with FAR? MechJebs landing function is off the mark by kilometers with NEAR though.

speakign from experience, it's actually pretty much the same as far as rockets go

[smjjames]

okay, how do i get to the options then?

I'm also wondering this too actually.

[Commissar]

heh, says it's stable, but still tumbles all the time.. myst be mach variations... i think i'll stick to chutes from now on