Aircraft Tips

[Argentvive]

I haven't played KSP in a while (I seem to go through phases with it) but now that I have some free time I've decided to come back to the game. I can build rockets easily enough, just point and shoot, but aircraft are considerably more difficult to master. Most of the things that I build have a painful tendency to spiral out of control... While still on the runway.

I don't know the first thing about aerodynamics, that's not something I've ever studied, so I'm curious if anyone has any basic advice for beginners? Like I said, I struggle to even get off the ground, so any guides, tutorials, videos, or general advice would be appreciated.

Thanks for the help.

[Ogre420]

This might help...

http://forum.kerbalspaceprogram.com/index.php?/topic/47818-basic-aircraft-design-explained-simply-with-pictures/

[FourGreenFields]

Was about to post the same link.

[hamburger helper (AI assistant)]

Basically, keep the center of lift behind the center of mass and make sure your plane has enough lift. Lift makes you take off, so experiment with different amounts of wing.

[maestro]

Also it helps to start out by imitating real world designs that are proven to work before you get too crazy.

[Ragnaman]

i found it really simple (after trial and error);
Weight is very important;
"Lift" should be behind of the center of mass pointing upward;
Y and Z axis of center of mass, ideally should be on Y and Z axis of where "Lift" vector starts;
(X axis is different as the "Lift" vector should be behind the center of mass);


example

http://steamcommunity.com/sharedfiles/filedetails/?id=581462182

http://steamcommunity.com/sharedfiles/filedetails/?id=581462914


If your plane design is good, the plane should fly indefinitely straight without any control input
http://steamcommunity.com/sharedfiles/filedetails/?id=580929311

[Argentvive]

Originally posted by vaprak:

This might help...

http://forum.kerbalspaceprogram.com/index.php?/topic/47818-basic-aircraft-design-explained-simply-with-pictures/

Thanks for the link. It was amazingly helpful! I was able to build a basic jet capable of flying in a straight line without having to rely on SAS! It was also capable of landing without parachutes!

I think I still have a long way to go before I can build anything really spectacular, but at least I have a place to start now. Thanks.

[FourGreenFields]

Originally posted by skylorz:

Originally posted by vaprak:

This might help...

http://forum.kerbalspaceprogram.com/index.php?/topic/47818-basic-aircraft-design-explained-simply-with-pictures/

theres quite a few things in there that arent right.

Like?

[FourGreenFields]

Originally posted by skylorz:

Originally posted by FourGreenFields:

Like?

high wings are not more "stable" than low wings, nor are low wings more maneuverable

At the very least when adding some di- or anhedral, low or high mount will make a difference though.

Originally posted by skylorz:

also the thing about angle of incidence and the disproportional increase in lift is complete bollocks

Maybe not as much at low AoAs, but once you're closing in on 45° AoA you'll definitly notice a difference with AoI.

Originally posted by skylorz:

the tail isnt even supposed to generate upward lift.

It doesn't usually in level flight. It will however generate lift at an AoA. Unless your plane is ridiculously stable maybe.

Originally posted by skylorz:

anhedral wings are also unstable, but again that doesnt mean theyre more maneuverable.

Usage of ailerons causes a yawing movement in opposite roll direction. Also, rolling at an AoA turns your AoA into your slip angle.

And anhedral wings cause a rolling movement in opposite slip direction -> faster rolls.

Originally posted by skylorz:

not sure how well ksp models realitity but you sure dont want to be using this if youre building a real aircraft :p

True, but that's because you don't calculate anything when following that guide.



Read through it again though, and the one thing that isn't correct anymore, is that stock KSP now has an aerodynamics modell, so fairings do reduce drag.

[FourGreenFields]

Originally posted by skylorz:

Originally posted by FourGreenFields:

At the very least when adding some di- or anhedral, low or high mount will make a difference though.

the effect of high or low mounted wings in terms of stability is really negligible compared to other factors.

Maybe. Either way, it does have an effect, so it's not wrong.

Originally posted by skylorz:

Originally posted by FourGreenFields:

Maybe not as much at low AoAs, but once you're closing in on 45° AoA you'll definitly notice a difference with AoI.

thats only because the wing with the higher angle of incidence will generally stall first, not because of the "disproportional increase in lift".

Except lift does get disproportional once you're at high AoAs. As said.

Originally posted by skylorz:

Originally posted by FourGreenFields:

It doesn't usually in level flight. It will however generate lift at an AoA. Unless your plane is ridiculously stable maybe.

the tail always produces lift, but always in the opposite direction of the main wing, so for the tail to generate positive lift the plane has to be flying upside down.

Replace "allways" with "generally" and yes, you're right.

Originally posted by skylorz:

Originally posted by FourGreenFields:

Usage of ailerons causes a yawing movement in opposite roll direction. Also, rolling at an AoA turns your AoA into your slip angle.

And anhedral wings cause a rolling movement in opposite slip direction -> faster rolls.

ailerons are for rolling, rudders are for yawing.

*facepalm*
Read what I wrote. Using ailerons -> unwanted yawing.

Originally posted by skylorz:

the only reason why anhedral wings would make you roll quicker is because theyre unstable and therefore throw you into a roll semi-uncontrolably (untill youre upside down). yes you do roll faster, but whats the point of extremely fast rolling if you cant control it, so calling it "better maneuverability" would be a bit stupid in my opinion.

edit: spelling mistakes

Except it will keep you rolling, until your slip angle is 0 again, and that can be controlled.

[Manwith Noname]

Originally posted by skylorz:

ailerons are for rolling, rudders are for yawing.

They didn't say otherwise. They said using ailerons to roll induces yaw in the opposite direction.

It strikes me that when going into details, you actually agree with the general overview of the link, you just want it worded slightly differently so as to be more precise, which is not really what the guide is for. The guide is to simplify how people understand aircraft, it's not about educating people so they can become real life aerospace engineers.

[FourGreenFields]

Originally posted by skylorz:

tails always produce downward lift, even in ksp (dont know how exactly this works in ksp). since otherwise you wouldnt be able to place the center of gravity infront of your main wings and still be able to fly.

angle of incidence doesnt change anything about the stability, the only thing it does is make the wing stall out faster, and therefore limiting your max flightpath angle.

Except you don't have to place your wings behind the CoM. Many planes have their wings behind the CoM, but definitly not all.
Also, if you are at an AoA, and not giving any pitch input, your tail wings will generate positive lift. Just that that positive lift will bring you back to lower AoA.

[FourGreenFields]

Originally posted by skylorz:

Originally posted by FourGreenFields:

Except you don't have to place your wings behind the CoM. Many planes have their wings behind the CoM, but definitly not all.

yes but then you have to have a canard on the front of your plane

Errrrr.... no?
If your wings are in front of the CoM and you're using canards, the thing will be ridiculously unstable.

[FourGreenFields]

Originally posted by skylorz:

Originally posted by FourGreenFields:

Errrrr.... no?
If your wings are in front of the CoM and you're using canards, the thing will be ridiculously unstable.

if you have two wings infront of the CoM then the most front one has to be producing downward lift, so were pretty much back at the original configuration but then reversed

Which would mean artificial stability. And I'm not sure if even the best fly-by-wire systems can handle that much instability.

[FourGreenFields]

Originally posted by skylorz:

Originally posted by FourGreenFields:

Which would mean artificial stability. And I'm not sure if even the best fly-by-wire systems can handle that much instability.

no that wouldnt mean artificial stability, depending on the configuration it can be perfectly stable

Wait...
- All wings in front of the CoM
- All control surfaces in front of the CoM
-> Still stable without fly-by-wire?

Either there's a misunderstanding here, or I seriously don't [censored] even.

[FourGreenFields]

Originally posted by skylorz:

Originally posted by FourGreenFields:

Wait...
- All wings in front of the CoM
- All control surfaces in front of the CoM
-> Still stable without fly-by-wire?

Either there's a misunderstanding here, or I seriously don't [censored] even.

still the front wing would have to be producing downward lift though

If you want to fly straight, yes. But that doesn't make it stable.