Basic question on biig Space Plane Wings

[davidpsummers]

I have a space plane that can reach suborbital trajectories. My new version needs more lift. The swept wing and delta wing in stock aren't enough. I see some planes with bigger wings. I think many of them just use stock parts? How does one do that?

I tried the wing connector, but I couldn't see how it should work? (It has a lift rating so it is to build bigger wings?)

Edited October 3, 2014 by davidpsummers

[el_coyoto]

You can add wings onto wings in the editor, they are a part just like another one : this is how you build big wings.

The wing connector is useful, because it is rectangular, thus making it easier to build bigger wings with a core of well aligned wing connectors and the outer border of the wings with nicer wing parts, like the delta (dunno if I'm really clear on this one without a pic lol).

Just don't forget to add struts if you notice too much wing flexing...

[Wingblaze]

If you'd like some examples of some really great spaceplanes and how to put wing sections together, I'd direct you over to Wanderfound's playground

http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread

You can get some good ideas over there with some of his bigger craft.

[endl]

look up a user named overfloater he does some amazing wizardry with stock parts. ive picked up a few techniques from dissecting his crafts.

[davidpsummers]

You can add wings onto wings in the editor, they are a part just like another one : this is how you build big wings.

The wing connector is useful, because it is rectangular, thus making it easier to build bigger wings with a core of well aligned wing connectors and the outer border of the wings with nicer wing parts, like the delta (dunno if I'm really clear on this one without a pic lol).

Just don't forget to add struts if you notice too much wing flexing...

I think I understand. They seem to "overlap". That isn't the same as clipping? It does look ugly.

[Alshain]

I think I understand. They seem to "overlap". That isn't the same as clipping? It does look ugly.

No, he means just attach them edge to edge. You can over lap them. The new ones coming from Spaceplane+ have a black edge designed for alignment purposes and are intended to be clipped. Take a look at my imgur album (signature), specifically the Hawk and the Eagle. The Hawk is SP+ and the Eagle is B9, both those wings have edges meant to be clipped on purpose. They attach to the plane width wise and are strutted length wise because each part can only have one attachment node. (Note: I hide my struts on the bottom of the wing, they don't often show in screenshots)

Then take a look at the Cardinal, it is using the (currently) stock wings, but it also has the modular design. That one isn't even strutted because it's fairly rigid on it's own. However those wings do not have the leading edges that clip into each other.

Hawk:

Cardinal:

Edited October 1, 2014 by Alshain

[Skorpychan]

Alternatively, have you tried less spaceplane?

Less weight needs less lift.

[el_coyoto]

No, he means just attach them edge to edge.

Yup, attached edge to edge is what I meant. As English is not my mother tongue, I might word things in a strange way sometimes...

Thanks for clarifying and posting an example picture : I answered the post during a short break at work and didn't take the time to do it properly.

... It does look ugly.

LOL I remember having more or less the same reaction the first time I assembled a wing in KSP. But I ended up getting used to this "piece by piece" wing construction method, and Alshain is right, by taking some care while placing the wing parts, you can make it look reasonably nice.

You may want to check on the Procedural Wings mod though : rather than building your wing by assembling parts, you define it by describing its length, thickness, etc to give it the shape you want.

[Franklin]

Hawk:

http://i.imgur.com/woKcKhs.png

Damn this is a soxy plane.

edit: really? .... is censored but not damn?

[Alshain]

Damn this is a soxy plane.

edit: really? .... is censored but not damn?

Thanks. The low wing, high tail plane design is becoming my favorite wing mounting scheme. It makes it easy to mount the landing gear so it's level on the runway and wide enough to be stable while still keeping the center of lift even with the center of mass and as a bonus keeps it out of the way of the cargo bays. The high engines, however, do cause a pitch down effect, it can be a handful without SAS on (but it can be flown that way). Even with the SAS landing has to be done at high speed with a drag chute or you won't be able to keep the nose up.

Edited October 1, 2014 by Alshain

[Jovus]

Are you sure you need more wing? I've found that most of the times when I thought that, the answer actually was that I needed more thrust. Spaceplanes tend to have tiny wings for their payloads compared to other planes.

[davidpsummers]

Well, that is probably the next step for this test plane, but if I want to bring stuff up, I will eventually need bigger planes and wings.

- - - Updated - - -

Are you sure you need more wing? I've found that most of the times when I thought that, the answer actually was that I needed more thrust. Spaceplanes tend to have tiny wings for their payloads compared to other planes.

Well, my guess is I need both. But maybe I'll try working on the thrust and see if the solves the lift...

[davidpsummers]

So something like this...

(in which case I can't really add a third wing because it will just be too long?)

Or this...

[This isn't the full plane, just wings stuck on something I was playing around with...]

[Friend Bear]

Yeah as they said, just add a wing to a wing. Rotate it, spin it, whatever you want. If it connects, it'll latch on no problem. Won't need struts either.

Also, consider putting them low on the plane:

Take a wing;

Hold the wing over the bottom end (not side but the very bottom, outside) of the plane's fuselage;

The wing will be pointing down - so press the rotate key and make the wing tilt 90 degrees;

Attach

(Just re-read - sorry that someone suggested it but at least hope my instructions helped)

It will look like a piper (although that is technically a mid-wing, but you get my drift). Sometimes this helps with lift when entering orbit from the atmosphere.

Also, you don't always need that much lift. Remember, more wings are more drag. Maybe you need better air intake, less mass, more thrust, etc.? You can fly horizontally right at the top of the atmosphere where air intake is closer to .1 and gun it, getting you up to 1800m/s sometimes. That will force you out of the atmosphere, then engage your thruster when no more intake.

Careful though. This method may require manual shutoff of the jet engines before one delivers more thrust than the other because of air intake loss; leading to spin out. Just set shutoff as an action group int he editor.

So something like this...

http://i.imgur.com/wus7u7q.png

(in which case I can't really add a third wing because it will just be too long?)

Or this...

http://i.imgur.com/ioOehug.png

[This isn't the full plane, just wings stuck on something I was playing around with...]

I like this and the lift is fine. As for design:

I personally like 2 jet 1 rocket. This will require less fuel and allow faster travel. With a spaceplane SSTO - the trick is to get speed in the atmo and not in orbit for the orbit to be obtained. (also, look below concerning center of mass and center of lift)

Let me log on and make one quick to show what I mean so you can get an idea. I'm not saying mine is the right way but it works and you can bounce ideas off that.

https://www.dropbox.com/s/2e16vfs907kdz1c/2014-10-01_00001.jpg?dl=0

https://www.dropbox.com/s/wjlfiphsyttcd8i/2014-10-01_00002.jpg?dl=0

https://www.dropbox.com/s/q9vyz22558vxrtt/2014-10-01_00003.jpg?dl=0

https://www.dropbox.com/s/cv0vx5qdl74m64v/2014-10-01_00004.jpg?dl=0

Check these out. Been a minute since I built a small one and I use a different rocket but its the same concept and will make it into orbit at about 90k round.

This is a good example of less-lift = more payoff, assuming your plane can travel fast with air intake. Those front ram intakes work better than the radial and I don't know if its from a bug or what.

The main thing is weight. If you don't have enough fuel, try replacing that rocket with a smaller one, like that small probe one. Its just to move the light plane higher into orbit, realistically. You are entering orbit speed with the jets at the high altitude since you don't enter orbit by going up, but instead by going horizontally.

As for bigger - use the same concept.

https://www.dropbox.com/s/pu9eu0qk0fixn9i/Untitled.png?dl=0

This is a shuttle I made that can both take off SSTO AND be shot as a shuttle launch, saving on fuel.

Ignore the protruding rocket pointing right at you and ignore unfamiliar parts. I used mod parts, but you can repeat the concept. There are two cargo bays, cockpit, and a liqui/oxy tank, followed by wings, solar and batteries (underneath) but still one or two engines. Here, there are two rockets because it is vertical take off. When I runway it from Kerb, I swap it the other way - 2 jets - 1 rocket. Look closely, its hard to see. There are two rockets and one jet nuzzled in-between.

I still get the speed I need and don't overweight from fuel or excess engines.

One extra note - I build faster planes. A lot of the larger ones you see have more engines to push that mass through the air. As you get bigger, expand. But I find it best to add more engines and no necessarily more fuel tanks. Apply an engine body radially rather than additional, radial tanks. Then decide if you need more fuel.

-------------

Another concern:

Look at your center of mass and lift point. Judging by looking at the wings, I bet your lift point is far out in front of your COM. This does not help lift. You can consider placing the wings so the COM is in front or on top of the lift point. I put it behind because, as you use fuel, the COM changes over time.

Too, you may want to try making your elevators horizontal and having a separate set of vertical stabilizers or hybrid elevator/stabilizers. But pay attention to wheel placement first, as was said. Very important to have the rear wheels directly behind/hugging the center of mass.

Edited October 2, 2014 by Friend Bear
multipost mayhem

[Claw]

Friend Bear,

You might want to edit your post above so that it flows a little better. You had several posts in a row so I went ahead and merged them. If you have more info to add and it hasn't been that long, it's easier to read if you edit in new information, rather than posting many times in rapid succession.

Thanks!

~Claw

[Wanderfound]

Also keep in mind: once .25 drops, stock fuselages will have lifting body properties. This substantially decreases the amount of wing required.

If you really want single-piece huge wings, Procedural Wings will do the job for you. But it's not necessary; you can make big jigsaw wings that work just fine.

[Ruedii]

As a note, more speed equals more lift from less surface. This results in less drag overall. Remember, your space plane will be landing with it's dry weight. It's landing speed will usually be half it's takeoff speed. Your wheels can handle quite a high decent landing speed, especially if you double up the main landing wheels. Generally you should be able to safely land at 120m/s when you are on a nice low glide slope and use proper flaring. The big concern is that your rate of decent doesn't get to high.

As of making sure you can take-off. The wheels can safely handle takeoff roll speeds that are incredibly high. Your main limiting factor is the runway, and the solution for that (short of Modding KSP to have a longer runway, or rolling your SSTO out to the feild by the runway) is to add more thrust. If you really want to add some umph you can even attach some seperatrons to use as jtags, or even use some small boosters for launch. It's not really an SSTO if you drop them. You can keep them on if you want to get the SSTO bragging rights. seperatron-based jtags will be recoverable if you add a parachute, but the small booster will place your seperation point too high.

Another option is to do an angled takeoff with a launch-clamp. I still haven't been able to design a rocket-powered catapult sled, but I've considered it, so I'll throw the idea out there.

[Alshain]

So something like this...

http://i.imgur.com/wus7u7q.png

(in which case I can't really add a third wing because it will just be too long?)

Or this...

http://i.imgur.com/ioOehug.png

[This isn't the full plane, just wings stuck on something I was playing around with...]

Ok, so a few problems here.

1. Always screenshot planes in the SPH with CoL and CoM showing if you want troubleshooting assistance. It helps a lot.

2. Also, showing the wheels would help, many problems with take off are due to poor wheel placement in relation to CoM.

3. I think this plane might have a hard time lifting due to forward weight. Generally you want the bulk of your weight in the rear to help lift off the runway and keep the nose up while landing. Fuel is heavy. Think of it this way, your plane body is a lever, the rear wheels and center of mass are your fulcrum, and the control surfaces are the downward force applied to one side to lift the other side. If your front end is too heavy, the control surfaces won't have the strength to lift it.

4. Avoid Jet Fuel only parts for SSTO's. In the grand scheme of things, your jet engines will use very little fuel to get to space and the added weight of a dedicated part is not worth that trouble. Just use LFO tanks only... unless you need the shape, like the adapter behind the cockpit. On that same note, that adapter has enough jet fuel to get high and fast enough to switch to rockets by itself anyway so you really don't need the Mk2 Fuselage

5. I really need to see the CoM/CoL because the wings look very far forward and I have a feeling your CoL is probably on top of or in front of the CoM.

6. Don't forget the control surfaces, it's not going to do much without those.

7. I disagree with the above comment on engines. Once you strip the dead weight of that Jet Fuel tank, that Turbo jet is all you need for a plane that small and the LV-909 can use the help, it's not that powerful. Also 2 Jet Engines means you have to keep a greater attention on your intake air and manually shut off the jets, which isn't hard but it is more complicated. An even number of Jets is even worse because have to keep at least 2 running all the time, with an odd number of jets, even if you have 3, you can shut off 2 a lot sooner to stretch the intake air for the 3rd. All in all, for a bird this size, 1 Turbo Jet is plenty.

That is not to say, there are not reasons to use 2 turbo jets (obviously the image I posted earlier does) but I don't think it's necessary in this case.

I do however agree that the 48-7S engines, though less powerful, are very good for plane ascent because they are so light and have almost the same fuel efficiency as the LV-909. The other option is to switch to dual turbo jets after all and use a single Toroidal Aerospike which has the same isp as a LV909 in a vacuum but a lot more thrust and better atmospheric ISP. That is what the Hawk image has.

[TABLE=width: 500, align: left]

[TR]

[TD]Engine[/TD]

[TD]Thrust[/TD]

[TD]Mass[/TD]

[TD]ISP(atm/vac)[/TD]

[/TR]

[TR]

[TD]2x 48-7S[/TD]

[TD]60kN[/TD]

[TD]0.2t[/TD]

[TD]300/350[/TD]

[/TR]

[TR]

[TD]4x 48-7S[/TD]

[TD]120kN[/TD]

[TD]0.4t[/TD]

[TD]300/350[/TD]

[/TR]

[TR]

[TD]2x LV-909[/TD]

[TD]100kN[/TD]

[TD]1t[/TD]

[TD]300/390[/TD]

[/TR]

[TR]

[TD]1x Toroidal Aerospike[/TD]

[TD]175kN[/TD]

[TD]1.5t[/TD]

[TD]388/390[/TD]

[/TR]

[/TABLE]

As you can see, the LV-909 kind of loses. It's a best of both worlds... master of none type thing. Unless I'm intentionally trying to build in a low tech tree, I never use it (on planes).

Edited October 2, 2014 by Alshain

[Friend Bear]

Friend Bear,

You might want to edit your post above so that it flows a little better. You had several posts in a row so I went ahead and merged them. If you have more info to add and it hasn't been that long, it's easier to read if you edit in new information, rather than posting many times in rapid succession.

Thanks!

~Claw

Yeah I have to stop treating forums like a chat. My bad (90s child). I also blame it being way past my bed time.

I will reorganize and add to it midday.

-----

Edited but it covers what I want. If you have questions, ask. Sorry if it is confusing.

Edited October 2, 2014 by Friend Bear

[Friend Bear]

Also keep in mind: once .25 drops, stock fuselages will have lifting body properties. This substantially decreases the amount of wing required.

If you really want single-piece huge wings, Procedural Wings will do the job for you. But it's not necessary; you can make big jigsaw wings that work just fine.

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/Kerbodyne%20Showroom/screenshot10_zpseeaec006.jpg

I have to ask -

How did you get the color? What mod? I'm too nervous to use textur mods since I am already running 25 mods.

[Wanderfound]

I have to ask -

How did you get the color? What mod? I'm too nervous to use textur mods since I am already running 25 mods.

Kerbpaint: http://forum.kerbalspaceprogram.com/threads/50008-0-23-KerbPaint-Paint-layering-for-parts-(September-23rd)-(Same-Old-Still-Works!)

It's unmaintained zombieware (although there are folks committed to doing paintjobs for the new .25 parts ASAP), but it works fairly smoothly. Just be sure to dig out and delete the archaic copy of ModuleManager that it has buried in a subfolder.

[Friend Bear]

Thank you, much appreciated. Gonna be fun to use.

[Wanderfound]

Thank you, much appreciated. Gonna be fun to use.

It also has an irritating bug where the paint sometimes disappears from half of your symmetry-placed parts in between the SPH and runway (I think it's related to the similar action group bug in the stock game). Leaving the paintjob as the last thing before heading to the runway should help prevent this.

But, yeah: fun.

[Alshain]

It also has an irritating bug where the paint sometimes disappears from half of your symmetry-placed parts in between the SPH and runway (I think it's related to the similar action group bug in the stock game). Leaving the paintjob as the last thing before heading to the runway should help prevent this.

But, yeah: fun.

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/screenshot0_zpsaf333ecf.png

I'll just leave this here.

[Friend Bear]

Lol The guy in the top right must be the camera man's brother.

Ugh now my next few rockets are going to mimic this...