Outsourcing my troubleshooting

[Assault Bunny]

Okay, I really need help with my spaceplane design. While I can get it off the ground (usually), it always pulls to the right on the runway, and no matter what i do doesn't seem to have enough thrust to reach orbit. Anyone who can fix this design wins... I dunno, a big thank you and an ego boost.

I uploaded it to the spaceport, but it's not showing up... In the meantime, here's a picture

[Vanamonde]

Diverting on the runway usually results from landing gear not mounted vertically to the ground, or the weight of the plane causing flexion so that the landing gear is forced out of vertical. If it's the later, some struts might help with structural rigidity.

Do you really need the second set of wheels? The big rover wheels? They require electricity for power, which is redundant if you're going to be using engine thrust. Also, since they're made for rovers, they have a maximum safe speed and will pop if you exceed that. It may be higher than your landing/takeoff speed. Either way, two sets of wheels adds weight.

The ram intakes have a better air/drag ratio, so replacing the scoops with those will allow the plane to reach higher speeds. And that's important, because for spaceplanes, the trick is to build up as much speed as you can in atmo and only use the rockets to circularize the arc you achieve on jets.

On that note, you're using LV-N nuclear engines for your rockets. They are fuel-efficient, but quite heavy and have a tiny thrust. That's not good for SSTOs, which need to build up speed quickly before gravity drags them down again. I'd suggest replacing those with the 50 thrust rockets, which are weaker but also MUCH lighter, or some of the stronger engine types that will convert fuel-weight to speed at a much more rapid rate.

By the way, I see an RCS tank, but hardly any thrusters for it.

And lastly, I think that much weight would benefit from substantially more lift.

[Assault Bunny]

This is why it would be useful if the spaceport actually worked. I've uploaded twice now, and both times it says it's worked, yet "My Add-ons" is still blank.

The rover wheels don't touch the ground when the front gear is lowered. The idea is it goes to the Mun, lands, then lowers the front landing gear and moves around as a rover. That part actually works, it's the going to the mun part that doesn't.

The engines are as follows, from the center moving out: LV-T30, Turbojet, Basic Jet, and LV-Ns. The idea there was jets to build up speed and altitude in atmo, the 30 to get me from just under flame-out altitude to space, then nukes to the moon and back. Problem is I can't break atmo.

Since the spaceport refuses to work, any other ways to easily share the craft file?

[Rune]

This is why it would be useful if the spaceport actually worked. I've uploaded twice now, and both times it says it's worked, yet "My Add-ons" is still blank.

The rover wheels don't touch the ground when the front gear is lowered. The idea is it goes to the Mun, lands, then lowers the front landing gear and moves around as a rover. That part actually works, it's the going to the mun part that doesn't.

The engines are as follows, from the center moving out: LV-T30, Turbojet, Basic Jet, and LV-Ns. The idea there was jets to build up speed and altitude in atmo, the 30 to get me from just under flame-out altitude to space, then nukes to the moon and back. Problem is I can't break atmo.

Since the spaceport refuses to work, any other ways to easily share the craft file?

Ok, then it should be relatively simple to switch the LV-N's with LV-T's (30 or 45, matters little), and put a single nuke on the middle. You don't need the thrust in space, and that way you pretty much double the T/W while getting a plane 1 ton lighter (better mass ratio, so better delta-v). If you say you lack thrust to get out of atmo, I am assuming you can make it to at least 20 kms and >1,200 m/s, ideally 25kms and >1,500m/s. Oh, and forget about standard jets, they are wasted weight when you go over 10,000m IMO.

Also, a flight trick: when you are nearing flameout, turn the rockets on and thrust back to around 50-66%: you can get an additional push from the jets until ~30kms. But beware, you are courting a flameout induced spin that way, you'd better be quick at turning them off.

And last but not least, if all else fails, MOAR INTAKES! With 6-1 intake-engine ratio or higher you can get to such high speeds (>2.200m/s) you can circularize on ion engines, I kid you not. A handy trick: by adding a strut to the front of the tanks, you can clip two intakes per tank (without activating part clipping, too), and they actually look better IMO (one upside down on the back of the strut or the tank, the other on the front of the tank).

Oh, and I don't use the spaceport at all, I upload all my crafts to mediafire and post the links here. No wait, and I trust it more than KSP's servers, especially after the great crash.

Rune. Hope that gets you there!

Edited April 28, 2013 by Rune

[HoY]

Personally I would drop the jets and LV30's and stick with just one pair of turbojets and a single LVN. Or possibly a pair of LVN's. burning them inside the atmosphere has a stigma everyone keeps talking about but in truth they are more efficient than every other LFO engine available starting at 10,000m! Mind you were talking 400isp at 10km, but at 20km were already over 750s.

My point is, using LV30's to get out of atmosphere is fine, but chances are your going to use enough of your fuel supply that you'll need to refuel in orbit if you want to take the plane anywhere besides back to the ground.

Another thought is this. Center engin LV909, next out is a pair of turbojets, then outside that a pair of LVN's. just use the 909 with the LVN's while you are getting out of atmosphere and dissable it as soon as you are clear of the atmosphere. Circularize with the nukes and perform everything else with them until you are ready to land again.

I agree with the intakes(ram not scoops). I would personally go with 8 intakes per jet if you can find the space for them, that will get you to 28km at half throttle I wouldn't try for higher with a dual turbojet setup, as a flameout on a wide craft like this would be very hard to recover from.

Edited April 28, 2013 by HoY

[Assault Bunny]

First, there's nowhere to put more ram intakes on. The ones that are there decide they don't fit anymore if I look at them funny, and the bi-coupler attachments refuse to go on outright. Swapping out an engine requires dismantling most of the wing structure! With Rune's suggestion, I topped out at around 1200m/s at a little over 20km. Once I go over 22k, though, I flameout. My best run so far, I got to about 46km.

Here's the updated craft file, I hope: http://www./download.php?6nvulqotcvvt18d

[HoY]

To place parts on spaceplanes you usually have to turn on part clipping, by pressing alt+f12 and pressing the toggle.

And 46km on just jets? Or apoapsis of 46km on jets? Or total altitude with both jets and rockets?

Edited April 28, 2013 by HoY

[Rune]

Did you try putting the strut on the front of the engines? Not on the middle attachment point, mind you, just a hair to either side. Then without part clipping on (so you can't consider it cheating), stick them somewhere else, then move them, one to the tank and the other to the front of the strut. It's what I did before I discovered part clipping and stopped caring (because the SPH and VAB are buggy enough on their own, and frankly I consider aesthetics more important).

See this design for the final result, with two intakes on each attachment point. I hadn't discovered part clipping back then:

Rune. You can, of course, grab it from my thread for reverse-engineering purposes.

[Assault Bunny]

To place parts on spaceplanes you usually have to turn on part clipping, by pressing alt+f12 and pressing the toggle.

And 46km on just jets? Or apoapsis of 46km on jets? Or total altitude with both jets and rockets?

Around 22km on just jets, then the 30's burning out all their fuel, then the nuke. So apo of 46km.

[HoY]

Okay, I'll be home in a couple hours and ill take a closer look at it, it looks to me like it would only need very minor changes to get into orbit. Sounds like you need some fuel lines moved around also

[Assault Bunny]

I have no fuel lines. The 30's and the nuke have separate tanks. In theory, I should only need the 30's to get from high atmo to space, considering this is supposed to be a mun lander/rover, then just the nukes to get home.

Also, extra props if someone can fit in an inline clamp-o-tron without ruining the aesthetics too much

Edited April 28, 2013 by Assault Bunny

[HoY]

No fuel lines is the problem I was referring to

[Assault Bunny]

Here's one of my other attempts, the Dragunov.

Currently, after shifting a few things around to get the lift right into the center of mass, I can't get it off the runway without breaking off the nukes.

http://www./download.php?lmdd95xdt1gdjm9

Feel free to get rid of the mk1 fuselage if you want.

[HoY]

Is that meant to go to space? It has about 500L too much jet fuel hehe, although I do like the profile!

[Levelord]

Aw I just managed to make changes to your first craft to fly into space and then you released a new one

I also got a later design into a stable orbit, but I didn't take screenies

Edited April 28, 2013 by Levelord

[Assault Bunny]

Actually, that was my first failed design. The Artemis is the 3rd.

I can't see anything different. What did you change?

[Levelord]

Well I changed out 4 jet fuel tanks for rocket fuel tanks because you didn't need that much jet fuel. I also added fuel lines and strutted the entire thing to make it rigid. Oh I also added an ASAS later on because the avionics package is useless in space. I'll get a craft file ready for you soon.

edit: Craft file: https://dl.dropboxusercontent.com/u/16683090/KSP/Artemis-3B.rar

Edited April 28, 2013 by Levelord

[Assault Bunny]

Okay, am I doing something wrong? I can't get anything to take off before it goes all the way off the runway, which usually results in the nuke engine slamming into the ground.

[Levelord]

I take off gradually after I hit the grass. If you want, you could simply move the gears closer to the center of mass to make it easier to take off. Like I said though, I tried to change very little about your design apart from adding struts and fuel lines. But perhaps you might want to move the nuclear engines forwards?

[Assault Bunny]

Nuke's the center one. Only way to move it forward would be to move everything else back. Also I need as long a wheel base as possible for rover mode stability. I imagine landing this thing on the mun is going to be a bitch

[Levelord]

Nuke's the center one. Only way to move it forward would be to move everything else back. Also I need as long a wheel base as possible for rover mode stability. I imagine landing this thing on the mun is going to be a bitch

On another note, I really liked your Dragunov plane. The center jet engine flames out before the other two which lets you know when the jets are on the verge of giving out and I think it's engineering genius! I've also made some adjustments to your plane, and had a lot of fun getting it into space. Your design is very aesthetically pleasing too. Here's the craft fle:

https://dl.dropboxusercontent.com/u/16683090/KSP/Dragunov.rar

[Assault Bunny]

Okay, made it to orbit with the Artemis, currently heading towards the Mun, with about 1/8th of a tank of fuel left. I'm concerned about my chances of getting home.

In other news, since posting the Dragunov, I changed the design somewhat...

Meet the Mk2 http://www./?4nakysyke5ssxoe

Edited April 28, 2013 by Assault Bunny

[Assault Bunny]

Yep, as I suspected, I have no idea how to land this thing safely

[Rune]

On another note, I really liked your Dragunov plane. The center jet engine flames out before the other two which lets you know when the jets are on the verge of giving out and I think it's engineering genius! I've also made some adjustments to your plane, and had a lot of fun getting it into space. Your design is very aesthetically pleasing too. Here's the craft fle:

Errr... Levelord, where are the rest of the intakes? No way you can get this to 2,000m/s on just two rams and two radials, right? Or I am missing something? That 6.8 max air tells me something fishy is going on... Also, since you already did everything, I won't even try. But I might steal some aesthetic details. By the way, you remember I have a shuttle waiting for you to name it on my thread, right? You certainly earned it

And Bunny, it is very difficult to land planes on airless worlds, which is why the ones I send there always have extra landing struts to become tailsitters. Again, examples on my thread.

Rune. Heavy clipping, I presume?

[diegzumillo]

Okay, made it to orbit with the Artemis, currently heading towards the Mun, with about 1/8th of a tank of fuel left. I'm concerned about my chances of getting home.

In other news, since posting the Dragunov, I changed the design somewhat...

Meet the Mk2 http://www./?4nakysyke5ssxoe

That design works? interesting... I never thought about not using the turbo jet and ram air intakes for space planes, they just seem like the obvious way to go. And it's been a long time objective for me to make a space plane with nuclear engines.