Military Aircraft

[Dr.Narwhal]

Hello, this is just an open decision about the design of KSP Military Aircraft. Feel free to upload pictures of aircraft. Feel free to have constructive conversations about these aircraft.

 

[Dr.Narwhal]

I've found it hard to balance weight on my aircraft. Its ether tips backwards or doesn't take off. Sometimes I get that sweet spot but its uncommon. Any advice would be nice.

[eddiew]

You might find some inspiration in this thread...

Pictures will help us diagnose the problems you're having, there really are many ways to build a functional - or dysfunctional - aircraft, and it's hard to guess at your specific issues without a visual aid.

Generic advice:
Pay attention to the CoM and CoL markers when designing. Ensure the CoL is slightly behind the CoM. You can tell before you launch whether that plane will tip or get stuck on the tarmac just by the position of the CoM relative to its back wheel. Consider leverage with your control surfaces. Common error is that pitch surfaces end up very near the CoM and have nothing to work with - pitch control should be as far back or as far forward as possible.

Also, pay attention to how real planes look... common starter mistake is to slap many engines at the back of a short fuselage and wonder why it's not stable in flight, but I don't believe there's a real plane with that configuration  

[Dman979]

Moved to Spacecraft Exchange, since this is about KSP craft.

[Thor Wotansen]

On 6/12/2018 at 5:25 PM, Dr.Narwhal said:

I've found it hard to balance weight on my aircraft. Its ether tips backwards or doesn't take off. Sometimes I get that sweet spot but its uncommon. Any advice would be nice.

You need to place the landing gear with the location of the center of mass in mind, not only where it is when you build the craft, but where it will be when the fuel drains.  The mod RCS Build Aid has helped me greatly in the past, but it doesn't seem to be working currently.  I usually place the landing gear just a bit behind the farthest aft the COM gets, and since I try to design so the COM doesn't move much, that means the force necessary to rotate on takeoff is fairly small.  I've also found that canards help, as well as situating the landing gear so that the craft rests in a slightly nose up attitude.  This means that you won't be fighting negative lift on your takeoff roll in order to rotate.  Also, I tend to disable steering on all but the front wheels if I'm using small or medium landing gear.  This just makes ground handling more intuitive, and allows fine adjustment at high ground speed.  In general, build your plane so that it flies first, then put on the landing gear so that it handles reasonably on the ground.  If you want something to to great on the ground build a rover.  It's possible to have a plane that can land in crazy places, but not without understanding the balance of all the things and some good piloting.

[Dr.Narwhal]

On 6/12/2018 at 4:42 PM, eddiew said:

You might find some inspiration in this thread...

Pictures will help us diagnose the problems you're having, there really are many ways to build a functional - or dysfunctional - aircraft, and it's hard to guess at your specific issues without a visual aid.

Generic advice:
Pay attention to the CoM and CoL markers when designing. Ensure the CoL is slightly behind the CoM. You can tell before you launch whether that plane will tip or get stuck on the tarmac just by the position of the CoM relative to its back wheel. Consider leverage with your control surfaces. Common error is that pitch surfaces end up very near the CoM and have nothing to work with - pitch control should be as far back or as far forward as possible.

Also, pay attention to how real planes look... common starter mistake is to slap many engines at the back of a short fuselage and wonder why it's not stable in flight, but I don't believe there's a real plane with that configuration  

Thank you for the help. I tried it out. I found it is easier to balance weight on bigger aircraft like a C-17 as opposed to an F-15, however, your advice helped a lot. Thanks.

[Triop]

What is wrong in this picture :

[Dr.Narwhal]

14 hours ago, Triop said:

What is wrong in this picture :

 

Nothing I can see. Cool plane.

[eorin]

15 hours ago, Triop said:

What is wrong in this picture :

Try to place landing gears on another spot, sometimes its just a clipping problem.