SSTOs! Post your pictures here~

[Rune]

The nose you mean

Opening the nose allowed for rear engines and stabilizer to be fitted. With out that it would never been possible to get the performance. Needed.

And that is awesome, since it means hinges are still a thing in 0.21. I gotta work on one myself!

Rune. Good SSTO, but the part count is way above my getting-annoyed-at-lag limit.

[pa1983]

Yea part count is hard too keep down but the k-prize challenge required stock engines and wing. Plus its just fun to see how fare one can go. I don't expect people to actually use the craft.

Lag can get quite annoying at Duna during some periods. don't know what my fps is but its slow but steady. 20-25 I would estimate but that's just a guess. Its a bit slower then I'd like but its still perfectly flyable.

Speed up to 3x they make great youtub videos.

Edited August 26, 2013 by pa1983

[Captain Sierra]

Help. What's wrong with this picture?

Rhetorical. How do I fix it?

In this configuration, it will pitch up pretty strongly when I try to do orbital burns or even when I am at high alt. I ran into this issue once with my Orion but the wings where higher and the issue was not as pronounced. I was also able to mount stuff diffferently to fix it.

[KissSh0t]

The center of lift is above the center of weight and center of thrust..

You can fix it by having all three as closely aligned as possible.

[Captain Sierra]

Okay, I know what's wrong and I know what it should look like. Lemme get a pic of the jet as a whole so I can get help with the design, which is what I need.

I know the engines have to come up. I'm not sure how to make that happen.

Edited August 26, 2013 by Captain Sierra

[KissSh0t]

You could have the engines on the rear tips of the wings and have the wings closer to the center of weight?

Edited August 27, 2013 by KissSh0t
spelling

[Captain Sierra]

The high-up wing mounting is kind of a trademark. This time, I had to mount it lower than on my Orion. On the Orion, it was close enough. Here, not so much. I'll keep working on it.

[Guest]

One possibility it to raise the wing till the thrust center-line is on COM. I didn't see if you have pWing installed, but you can make ANY object with precise dimensions with that. Just an idea. Or you could perhaps add a girder / spine up on top, and put the wings on that. You could also work some anhedral into it if you're into that like the C-5 and Antonov.

[Captain Sierra]

Can't do that or else the control surfaces will start clipping into the cargo bay doors. Also, elevating the wings too much results i and offset CoM.

[Guest]

This is what I puttered at on and off today, my first stock SSTO. My learning curve has been backwards, big to small LOL! But it was though. This is not finished but you can mess with it. COM is too whacked for positive control on re-entry. I had it once, and I know why. This is like the 50th revision today, and I didn't save them, but I know what I need to do. Basically move fuel storage backward. Those fuselage sections with fuel are a stone in my shoe for staying balanced. I am going to go without the TAC balancer too this time, totally stock.

Check the altitude, speed, and fuel readouts for the performance.

================================

DOWNLOAD (remember this is an alpha)

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Climbout at 45 degrees to 10000

30 degrees to 15000

20 degrees to orbit

RCS on at 20000

Keep reducing thrust to avoid compressor stall till 25000

Switch to rocket at 25000 or engine stall whichever first.

I enter all my orbits with two burns. Once I know I will get out of the atmosphere, I cut the rockets till I get near the apoapsis, at which point I will center the prograde reticle, and burn to circularize. Getting better all the time.

Edited August 27, 2013 by Guest

[Guest]

Captain Sierra perhaps try to line up the vertical lines of COL and COT, in some way. It might help. The other thing is to make sure your RCS setup is strong enough (sufficient number if RCS thrusters perhaps under the tail pointing down). You can overcome imbalance in design with sufficient RCS, even though it is inefficient. The other thing is to try reduced thrust climbout, or perhaps a combination of the two.

Edited August 27, 2013 by Guest

[pa1983]

Easiest way to maintain CoM is avoiding stacking and only have fuel tanks in parallel. That way if CoM is in the center of the fuel tank CoM will never move. Second option is on tank in the nose and one in the rear. Preferably same typ of tanks. Then drain them equaly. A small tank in ghe center can be used for automatic fuel balancing. You can combine both concepts for a perfectly balanced craft at all times.

3:e option is to drain fhe fuel in such a way that when your high up in the ascent profile CoM have moved over to CoL and in line with CoT. That way on can have jet fuel further forward an have CoM higher the CoT but one must balance the rigth amount of fuel for fhe intended fligth profile. One can also add a 5-10 degree angle on engines to compensate. I did that on the NV-1 to compensate for the fact that the ssto was basicly a Concord.

[Guest]

My problem seems to be just when it's completely empty, coming out of orbit. I don't have any control issues headed into orbit. Maybe some strakes on bottom

Edited August 27, 2013 by Guest

[KissSh0t]

My problem seems to be just when it's completely empty, coming out of orbit. I don't have any control issues headed into orbit.

That's the trick... making it so the craft when full or empty... is the same center of weight.

[pa1983]

My problem seems to be just when it's completely empty, coming out of orbit. I don't have any control issues headed into orbit. Maybe some strakes on bottom

Reentry is always the hard part and if it cant make it past the first 3 layers of atmosphere it will be almost impossible to land since it gets more and more unstable the lower you get until speeds drop below 300-400m/s.

Also Center of lift is not center of drag like som suggests so intakes should be fare back and closed if placed asymmetrically during reentry.

Also having CoM fare back even if CoL is as fare back is not a good thing either. Tends to flip and fly backwards. Try to have CoM close to the center of the fuselage.

Thats why I usually never use rear mounted engines any more because its unstable.

You can end up with a torque effect where drag and lift on the long nose easily spins the craft up, down or sideways around the heavy rear mounted engines.

I usually aim for C.M to be 3/5-1/3 to the rear of the fuselage length.

Edited August 27, 2013 by pa1983

[camulus777]

I'm taping another episode from today till probably Wednesday and want your help with some of your cool designs. Here is a link to the page explaining whats to come. If you don't have a design for the featured topic but have one that you would like in a future show send that one too.

http://forum.kerbalspaceprogram.com/showthread.php/46669-KSP-Ship-Submitions

[Captain Sierra]

Captain Sierra perhaps try to line up the vertical lines of COL and COT, in some way. It might help. The other thing is to make sure your RCS setup is strong enough (sufficient number if RCS thrusters perhaps under the tail pointing down). You can overcome imbalance in design with sufficient RCS, even though it is inefficient. The other thing is to try reduced thrust climbout, or perhaps a combination of the two.

The issue isn't super strong so I only expect to see it when I hit the upper atmoshpere and space. It has 480 units of RCS and 4 RCS blocks (not counting the command pod; RCS capable) and 4 port-linears on the wingtips for roll. I'll see about adding some more port-linears to the tail section to counter that. I also will be using this to test out the new kerbcom avionics.

[Hodo]

Help. What's wrong with this picture?

Rhetorical. How do I fix it?

In this configuration, it will pitch up pretty strongly when I try to do orbital burns or even when I am at high alt. I ran into this issue once with my Orion but the wings where higher and the issue was not as pronounced. I was also able to mount stuff diffferently to fix it.

Simplest answer is to move the three engines on the wings back behind the wings and up on the body of the aircraft to bring the COT in line with the COM. I have found setting them up like a triangle on the sides of the body work best for maintaining the stability.

But I myself am just now fiddling around with getting the "space plane" concept running to other planets. Seeing as I can now build them reliably to get to orbit. Now the hard part begins getting them to other worlds. The Mun is my first target.

[The Deep Space Kraken]

My first ever SSTO.

[Captain Sierra]

Simplest answer is to move the three engines on the wings back behind the wings and up on the body of the aircraft to bring the COT in line with the COM. I have found setting them up like a triangle on the sides of the body work best for maintaining the stability.

But I myself am just now fiddling around with getting the "space plane" concept running to other planets. Seeing as I can now build them reliably to get to orbit. Now the hard part begins getting them to other worlds. The Mun is my first target.

Can't do that either. The only body section not occupied by wings (where there would be nasty clipping) is back by the cargo bay. That would interfere with payload deployment. They gotta stay on the wings.

[winginson]

Finally got an SSTO working and I've been working on this series for a week now.

First is the IKN (Imperial Kerbal Navy) Swallow Mk1. This is my first ever working SSTO, 67 parts most of em radial intakes. Its *just* capable of a 70x70 orbit with enough juice to de-orbit, however it does get there having used only 1/2 its jet fuel although that doesn't do you much good as the reentry is brutal. Every kind of spin imaginable which can only be got out of with RCS and luck.

This is the IKN Swallow Mk3. Fantastic little ship, handles like a dream and incredibly agile. Again 70x70 *just* and gets there with 2/3rds of its jet fuel left. The main improvements are re-entry and take off, as it can comfortably come in very hot with zero control issues and can take off at 40m/s. As it can also take off at an angle of 80 degrees is being turned into a fighter with ASat capabilities.

This is the IKN Swallow Mk4 and Mk5, the major difference to the Mk3 being a docking port, solar panels and more fuel. The Mk4 has an extra flt400 while the Mk5 has an extra flt800. The Mk4 will do a 100x100 with fuel for playing around, the Mk5 will do 500x500 with plenty to mess around with. Flying characteristics are worse than the Mk3 being more prone to backflip with harsh use of the 'w' key, and the Mk5 is harder to get off the ground due to the extra length of the flt800 sticking out the back as pulling up to hard causes it to hit tarmac. They do have an RCS tank but not the thrusters as I haven't learned to dock yet and don't know where to put them.

I'm in a bit of a KSP slump at the moment. Can't dock no matter how many tutorials I look at, can't get a kerbal further than Minmus, can't get better performance or cargo carrying ability from my SSTOs. Still it was fun making these and I hope this hasn't bored all of you who have SSTOs capable of day-trips to Duna or those who fly around in things that simply shouldn't be .

[Guest]

Ok I revised the one earlier it is the first pic, the second pic is a very similar craft but as you can see having quite a bit more wing area and fuel, and one more jet engine. Neither fly satisfactorily enough to release. They are very tail heavy when empty. The engines.

The second one will make it to 25000 on air breathing engines and at full thrust, and will achieve 1500 m/s at the same time. Quite a beast.

Both are stock.

Note the unique tri main-gear - it was a necessity and luckily they all lined up

Going to have to place some ballast up front, plain and simple.

Edited August 28, 2013 by Guest

[Captain Sierra]

Finally got an SSTO working and I've been working on this series for a week now.

<SNIIIIIIIIIIIIP>

Air hogging much?

[pa1983]

Air hogging much?

Why care? Let him play the way he wants.

[Exothermos]

Ok I revised the one earlier it is the first pic, the second pic is a very similar craft but as you can see having quite a bit more wing area and fuel, and one more jet engine. Neither fly satisfactorily enough to release. They are very tail heavy when empty. The engines.

Going to have to place some ballast up front, plain and simple.

I love the simple wedge shape of both of these designs, but the problems you are having are because you are trying to ballance your craft WITH the fuel tanks. Which works great when they are full, but is a problem when you are out of gas. For the most part you should put the fuel where your craft's natural CG is. That way when they burn off, your CG remains unchanged.

Try this:

Strip your craft down to bare fuselage and engines. Place the fuel along a horizontal line in parallel with your CG. Now when they burn off your CG won't change (at least not much, see below)

Attach your wings to get that cool wedge shape. But see the problem? Your center of lift is WAY ahead of your CG, and as your fuel in the fuselage gets used up, it makes the difference even worse.

What you need to do is bring your center of lift farther back. Preferably behind the CG a little bit. That way as your fuel burns, your CG will shift back a little bit to meet your Center of Lift. The best way to do this (and keep this particular shape) is to plaster really "lifty" wings behind the CG to pull the Center of lift farther back. In this case I have done it by cramming Swept wings in there.

You can further control your Center of Gravity by controlling how your fuel flows. In this case I would run fuel lines directly to the engines from the rocket fuel tanks. That way the engines will use up the liquid fuel in your perfectly positioned Rocket Fuel tanks first, before taking from the long fuselage part. Run Fuel lines from your fuselage to the rocket tanks too. (Fuselage -> Rocket Tanks -> Engines ~~~)