Ways to make my new SSTO more stable

[Athelestan]

Hello,

I recently finally made an SSTO that I THINK will get into space. I have no idea how to fly them properly, I just made sure it handled well and didn't pull up or anything. It does rotate ever so slightly sometimes, but it flies well except that. So, I'm both showing off my plane, and asking for tips/advice to see if it will actually do what I want:D. I will attach the craft file (is dropbox okay?) and some screen shots of the plane. I used the keys 1-6 being 1, jet engines. 2, spikes, 3 nukes, 4 close the side intakes 5 close ram intakes 6 open solar panels. Here it is! https://www.dropbox.com/s/oqkv92nsbruh8qr/E_T_%20SSTO.craft?dl=0

I'm not sure if that's the proper way to upload in this forum, and will fix it if it's incorrect. Any advice to make this plane better would be a huge help!

Thanks guys.

[n0xiety]

This is a quick ascent spaceplane that doesn't care about fuel much. I made it so when you start climbing with 20 degrees it adjusts its own climbing degree as it goes up so you don't have to touch anything and micromanage and it reaches 120km orbit in about 9 real life minutes. This one can carry 2 tons easy, 3 tons if you push it. Tho you can always remove the clampotron and crew cabin modules and get 3 more tons of capacity making it go up to 6 tons. Now pay attention how the cargo bay and point of mass is aligned perfectly so any cargo that you can take wouldn't effect the planes stability. Another thing is notice how the wings are swept upwards and that causes the lifting point to go over the mass point which is great for stability. Always have your mass point a bit forward and under the point of lift. Align your point of mass and point of thrust horizantally for the space part of your ascent. This is not needed that badly for the atmosphere part since your ailerons will be able to compansate but it still is good to have your thrust aligned always. I use external fuel tanks for this design. You do not have to ditch them if you wanna cut down on the cost but that would save 100 more liquid fuel for the atomic engine when you reach orbit and total cost is about 1k dollars empty so yeah... Another thing is always make sure your plane is stable at every stage of the flight. I have seen so many people complaining about their planes flipping out and getting into flat spin when they reenter atmosphere. This is caused by fuel getting consumed and point of mass shifting. Make sure your plane is always stable at every part of the flight as the fuel gets consumed.

Another thing is you need to lock unnecessary options from your ailerons. Like tail is only for yaw and wing tip ailerons are only for roll while middle ailerons are for pitch. You can always use pitch on your tail by adding 2 ailerons to side but spaceplanes with no tail works better. You can always use action keys to create flaps. Notice how i use flaps while reentring and landing. Well that is about it i guess hope this helps mate.

Just a note about your plane. I noticed you have used so many engines on it which is really unnecessary. Engines are one of the heaviest part of planes i suggest you only use what you really need for the payload you are planning to carry. Using the right engine for the right part of the atmosphere doesn't mean you will save fuel. Instead the weight of the engines will just make you loose efficiency. 3 atomic engines are just overkill and it weights 9 tons... In my design i only use 1 and its conceled at the back. It hardly matters how many atomic engines you have once you reach orbit and you can just burn with 4* time warp. And those solar panels are really unecesarry too and causing drag, i only use 1 isotop generator and its inside the cargo bay.

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[Athelestan]

Thank you for the advice. What I did was I removed the 1 to 2 adapters, and used the spike engines, then stuck a single nuclear engine between them. I also double checked my weight with and without fuel, and it looked okay. I then moved all the wings up, and angled them, inorder to bring my center of lift upwards. I always thought it was supposed to be below! Thanks for the advice. Flying again now, wish me luck!

Edited May 10, 2015 by tetryds
Fixed image link.

[n0xiety]

Good going man hopefully you can reach orbit and have some fuel left for the return ride. Just a side note, i noticed all the RCS nozzles at the nose of your plane and got curious why you would use something like that. For turning your plane you can use reaction wheels. RCS is used for precision movement and only 6 of them is enough. At nose directly looking forward at tail directly looking backwards and all 4 sides of your mass point (up, down, sides). That is all you would ever need for docking.

[Athelestan]

Just a side note, i noticed all the RCS nozzles at the nose of your plane and got curious why you would use something like that. For turning your plane you can use reaction wheels.

Well I used that many because I used one, and it wasn't enough. The craft was too heavy. It isn't PERFECTLY stable, it pulls down the slightest bit, so I went a little overkill so when I get to higher atmosphere it wont go all wonky! I still have fine tuning to do, but I'm excited I got this far on my first SSTO. Thanks for all the advice guys!

[eddiew]

You could use the offset tool to slide your engines up/down a 'pixel' - should counter that tendency to drift off course, and will help in vacuum too If you prefer to use RCS for the visual effects, maybe consider vernors, since they have something like 18x the power of other RCS ports and use LFO so you won't need those monoprop tanks.

While I must admit this thing looks magnificently... kerbal... I do think you're adding drag that you don't need. The radial intakes are likely irrelevant, since 1 ram per jet will see you up to the point they die due to altitude rather than lack of air (unless you're going very slowly) and I'm fairly sure that the fuel lines aren't required since your main body is all node-connected. Also suspect the bi-adapters you're using are quite draggy, since they're kinda blunt. I love the serrated rear wings, but I do suspect they're not as efficient in the air as a single piece would be. From a functional engineering point of view, I'd definitely be looking to smooth things off and have less sharp angles and edges.

Oh, and I'd suggest you only need 2 airbrakes, and that they should be at the back. Otherwise you've a risk of spinning the plane when you deploy them and having it come down butt-first

That all said, I built

which isn't exactly a model of aerodynamic simplicity either. If it flies to where you want it to fly, and you like the look, don't worry about it