Designing aircrafts with FAR

[TheInsanePilot]

I've installed Ferram aerospace recently and immediately encountered problems(Duh!) However there are several problems I currently cannot get around.

1. Very little lift generated, resulting in high stall speeds(120m/s), and terrible agility. Some planes can't even take off at all now.

2. Some parts, even stock ones, cause the vessel to get stuck. 

3. Excessive vibration caused by SAS rendering SAS unusable on most planes.

4. Weird behavior when dropping things out of bomb bays/Cargo bays. (Maybe drag is calculated differently?)

Has anyone found solutions to these issues? All tips regard FAR will be much appreciated.

[p1t1o]

If you've been making planes in stock for a while, you might need to try and refresh the way you build aircraft. In my experience, build an aircraft that looks like it would fly in real life, and it will work in FAR. Use all of the concepts that you know about flight and lift.

Not enough lift? You need to look at your wing area, angle of incidence, wing sweep. (I sometimes angle my wings up a bit with respect to the fuselage centreline, increasing AoA when the plane is horizontal on the ground, helps with takeoff run and low-speed handling)

Too much drag for your enlarged wings? Bigger/more engines.

Wanna go fast? Make it pointy w/swept wings, deltas are nice and stable.

Wanna go high, speed not a priority? Long slender, unswept wings.

Wanna go supersonic? You'll find it very helpful to use "area ruling". This is a slightly more complex thing than the others, basically, give your aircraft a slight "wasp waist", ie: make it narrower in the middle. Give area ruling a google, you'll get it. Its tricky to optimise but FAR gives you some graphs and things to help.

If you still have trouble lifting off, check where your gear are positioned. If they are too far behind your CoM, you will not be able to get the leverage required to rotate on takeoff due to low speeds. Place main gear just slightly behind the CoM. Also try making the nose slightly pitched up when all gear are on the ground.

 

Its not clear what you mean when you say: " Some parts, even stock ones, cause the vessel to get stuck"

 

Note: gear have not been fixed yet, so you are bound to encounter problems on the ground with them. Apparently due to be fixed in 1.2

Tip: do not place main gear too far apart, just "a sensible distance". Dont try and give it a really wide stance to increase stability or anything, you will run into steering issues.

120m/s is quite fast for a takeoff roll, but don't expect to be getting off the ground at stock speeds. depending on the configuration of the craft, expect rotation speeds between about 70-100m/s.

 

Use flaps, and if you know what you are doing, leading edge slats as well. These are useful for improving lift and manouvreability at low speeds.

 

The drag issue with dropped payloads Im unfamiliar with.

The SAS issue is quite long-standing, you might be able to smooth things a bit if you find a mod that lets you "tune" SAS response coefficients (does FAR allow this, Im not sure?). Basically its just an issue to do with how the control feedback is generated. One response curve is not necessarily useful in all flight envelopes, and you've just swapped out stock aero for FAR, so its not surprising the SAS wigs out a bit.

 

Hope that helps and its not too basic!

[Van Disaster]

Opening a cargo bay in atmosphere will change drag, as it should, but also body lift. You'll have to give a bit more detail than "wierd behaviour" though. I would abandon stock SAS for aircraft control - I recommend Pilot Assistant, but there are other aircraft-tailored control mods. For the other issues you'll need to provide pics.

Edited June 28, 2016 by Van Disaster