troubles with FAR

[endl]

if i attempt a vertical climb i lose all control, what am i doing wrong?

Edited October 17, 2014 by endl

[mythbusters844]

This is probably because you don't have enough TWR to go vertically so you lose speed and stall. Maybe give us some more info about it (how fast it goes straight up, its purpose etc.) so we can help you more? Until then, the best thing to do is to increase the TWR one way or another by, for example, switching out the engines (I would replace the rapiers [the rapiers are only really useful for SSTOs; they provide little to no advantage to atmospheric jets and even have less thrust than the turbojet] with basic jet engines if you're planning to fly low in the atmosphere or turbojets if you want to be flying at high altitudes. If you are making an SSTO, try separating the jet engines and rocket engines.), decreasing weight, or by simply not climbing at too steep of an angle.

[endl]

ferram said it was intended ( you have to gently nose up otherwise it stalls) but i guess it wouldnt hurt to share in case i might learn something. its a science/service plane the neck is universal storage with KAS parts and sensors the center has a science bay ideally i want it to be able to reach 150km but if not i know it can reach my karbonite fuel station at 73km.

it has a TWR of 1.5 with 4 rapiers it weights about 26t. i encountered a few problems before switching to near where the plan flys alot better.

1. im not used to far so i dont know if im getting enough speed with those stats i was able to hit 1.5km/s. with my old stock aero SSTO i was able to hit 1.9 on a similar plane and 2.3 on a 6 engine 35t

2. structural instability, i used alot of struts but the plan seems to want to flex inwards regardless, i also see it the yaw drifting to one side at points even though everything and i mean everything is symmetrical

3. it blew up, i think from sheer forces during my speed run i started getting heat friction (might be deadly re entry) didnt happen in near. i lost a wing at high speeds

anyway i want to be able to do more "creative designs" but i also want a reason to use fairings, i dont think far is for me because i have to do less conceptual and more pratical designs, that said is near a good choice given i want the challenge of having to deal with drag forces but i still want to get away with some crazy designs?

Edited October 16, 2014 by endl

[steve_v]

with my old stock aero SSTO i was able to hit 1.9

FAR nerfs the jets to a more reasonable power level, and adds an approximation of RL maximum airspeeds, so most jets will die at ~mach 3 like they really should.

is near a good choice

Less fine-tuning, and perhaps a little more leeway for the crazy. NEAR won't break your plane so much, but it will still need to be at least airplane shaped

I guess it depends on your expectations - RL aircraft follow practical design rules for the same reasons they do in FAR/NEAR, stock aircraft don't really look or work like RL because the aerodynamic model is, um, 'creative'.

Edited October 16, 2014 by steve_v

[Wanderfound]

FAR allows plenty of crazy designs, they just have to be crazy designs with functional aerodynamics.

[endl]

far just seems to be for sadists, i mean this very plane is more or less following all the basic principles of aerodynamics i didnt make the wings too crazy i made them as close to a delta design as i could given the configuration of the payload i wanted it to carry but even flying "correctly" far just seems to eat through all my attempts at making this thing fly, i could have just given up and gone the b9 route with cheaty giant parts and done a very bland design but i wanted something that looked my own. so all im really trying to gauge is what far will allow because it seems to hate everything i do.

if anyone is interested i can upload the craft file but youll need to have a few mods:

KAS,robotics,near future solar/electrical,tweak scale, kerbal gps, karbonite/k+,universal storage with kas parts pack

Edited October 16, 2014 by endl

[Wanderfound]

FAR nerfs the jets to a more reasonable power level, and adds an approximation of RL maximum airspeeds, so most jets will die at ~mach 3 like they really should.

More like Mach 5.5, actually (in FAR, that is).

[Wanderfound]

far just seems to be for sadists, i mean this very plane is more or less following all the basic principles of aerodynamics i didnt make the wings too crazy i made them as close to a delta design as i could given the configuration of the payload i wanted it to carry but even flying "correctly" far just seems to eat through all my attempts at making this thing fly, i could have just given up and gone the b9 route with cheaty giant parts and done a very bland design but i wanted something that looked my own. so all im really trying to gauge is what far will allow because it seems to hate everything i do.

if anyone is interested i can upload the craft file but youll need to have a few mods:

KAS,robotics,near future solar/electrical,tweak scale, kerbal gps, karbonite/k+,universal storage with kas parts pack

1) FAR has been buggy since the 25 release, in ways that made planes fly badly when they shouldn't. The latest release appears to have fixed it.

2) What do the FAR aero analysis screens look like? If you look at the third post in the Kerbodyne thread linked in my sig, you'll find a guide on how to use them. If you post screenshots, I may be able to diagnose the problem.

[ferram4]

Well, this plane has really high wing loading (most planes that have wings that size for the body don't have their entire insides filled with fuel like this one definitely does), almost no vertical tail to speak of and way too much dihedral on the wings which is only going to make it fly worse. Give it more wing area, make sure that the CoM is forward enough so you're stable when you head out of the atmosphere at around 1.5 km/s, and use RCS when climbing out for more control.

[endl]

Well, this plane has really high wing loading (most planes that have wings that size for the body don't have their entire insides filled with fuel like this one definitely does), almost no vertical tail to speak of and way too much dihedral on the wings which is only going to make it fly worse. Give it more wing area, make sure that the CoM is forward enough so you're stable when you head out of the atmosphere at around 1.5 km/s, and use RCS when climbing out for more control.

So basically make a new plane thats more standard :-(

[*Aqua*]

There is a reason why planes look like planes.

[Wanderfound]

So basically make a new plane thats more standard :-(

Which particular features are you most attached to? You can probably hang onto them in one form or another.

That basic rear-delta airframe design will work fine, you just have to do it right:

[Guest]

So basically make a new plane thats more standard :-(

I'm pretty sure those sorts of sandwich biplanes don't fly well under FAR; they're artifacts of the terrible stock aerodynamics where a lift value means more than actual aerodynamics. Stacking wings isn't a good idea. Look at actual supersonic jets for inspiration when using FAR for spaceplanes.

[endl]

Well, this plane has really high wing loading (most planes that have wings that size for the body don't have their entire insides filled with fuel like this one definitely does), almost no vertical tail to speak of and way too much dihedral on the wings which is only going to make it fly worse. Give it more wing area, make sure that the CoM is forward enough so you're stable when you head out of the atmosphere at around 1.5 km/s, and use RCS when climbing out for more control.

the fuel tanks aren't actually resting on the wings but attached to the core fuselage, the wings are attached to the fuel tanks just not through the center, you can see it better in the last pic im linking. i read in keptins guide that dihedral low wing profile should give balanced stability i dont know how greatly this is effected by the fact that i boxed in the fuel tanks. what do you mean by vertical tail are you talking about the rudders? also as you can see im stacking intakes how necessary is this in far? do i need so many?

2) What do the FAR aero analysis screens look like? If you look at the third post in the Kerbodyne thread linked in my sig, you'll find a guide on how to use them. If you post screenshots, I may be able to diagnose the problem.

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Which particular features are you most attached to? You can probably hang onto them in one form or another.

That basic rear-delta airframe design will work fine, you just have to do it right:

i like the plane as a whole i think it has a pretty unique look then just attaching things center of object, i also like that it has a shorter wing span. but if were talking about whats absolutely necessary in the last pic above you can see the storage bays where i have all the various sensors and science packages so theres not actually alot of fuel in the main fuselage thats why i have the big fuel tanks on the sides.

Edited October 16, 2014 by endl

[Wanderfound]

Basically, you've still got a stock aero plane. You don't need stacked intakes (1-2 per engine is plenty) and you can't casually use wing segments as body panels without messing up the aero.

The wing boxing and intakes (mostly the intakes) are causing an insane amount of drag. The drag is the red line; in the Mach sweep (the second image, which you'd be better off doing with Upper set to 5 or 10) it should be barely distinguishable from the zero line.

Build it as if it were real plane: only one shock cone per side and maybe a couple of structural intakes under the wings or nacelles behind the cones. Lose the boxing, extend the wingspan by putting one structural wing piece between the deltas and the tanks, reduce the dihedral to no more than 5° or so if any at all and give it at least as much vertical stabiliser ("rudder", except the rudder is only the bit that moves) as the example plane I posted upthread. One really big fin or several medium size ones, either will work.

If you want to attach things off centre, go for high or low mount wings. High mount tends to increase stability, low mount tends to increase manoeuvrability. Shorter wingspans can be achieved through the use of strakes and canards, but be aware that there's a price to pay in terms of roll stability.

Edited October 16, 2014 by Wanderfound

[S1gmoid]

far just seems to be for sadists, i mean this very plane is more or less following all the basic principles of aerodynamics i didnt make the wings too crazy i made them as close to a delta design as i could given the configuration of the payload i wanted it to carry but even flying "correctly" far just seems to eat through all my attempts at making this thing fly, i could have just given up and gone the b9 route with cheaty giant parts and done a very bland design but i wanted something that looked my own. so all im really trying to gauge is what far will allow because it seems to hate everything i do.

Aerospace engineers used to say that a devil lives at the sound barrier. For decades people actually believed that at Mach 1, air becomes virtually like a concrete wall, making supersonic flight within the atmosphere literally impossible.

Things get awesomely ....ed up when you get to Mach 1, all FAR does is simulate that...

[Hodo]

So basically make a new plane thats more standard :-(

I have been making SSTO space planes since I started in KSP and using FAR. And you don't have to go with a more "standard" design. Ferram is right, your craft has to little wing for the mass of the craft. Now this doesn't mean you need to make the U-2 Spy plane sized wings or some other rediculous scaled wings, but you need more lift generating surface vs the mass of the craft. You could honestly get away with dumping half of your fuel and science gear and go for a lighter design. I have put a SSTO space plane of over 400 tons into an 100km by 100km orbit with FAR, it isn't impossible just challenging. Once you figure out what works you will think, "how did I ever not get it?".

Stick with FAR you wont regret it!

[Alshain]

If FAR is giving you trouble due to Mach changes, you should consider NEAR instead. Eventually it will lead you back to FAR, I swore after finding NEAR I would never use FAR again but I was wrong. Eventually I got better and then realized once I had the basics down for near, FAR added just a little more challenge rather than a big gaping chasm of challenge from switching straight from stock. I think that's what ferram4 had in mind when he made NEAR.

[endl]

i guess i dont really have a choice either i play with far and have a reason to use fairings and not be able to do any crazy designs or i dont play with it and have no reason to use fairings. anyway thanks for all the feed back i made a more "airplane" type plane and it flys much better but i feel like the fun was taken out of it

[Wanderfound]

i guess i dont really have a choice either i play with far and have a reason to use fairings and not be able to do any crazy designs or i dont play with it and have no reason to use fairings. anyway thanks for all the feed back i made a more "airplane" type plane and it flys much better but i feel like the fun was taken out of it

Try flying your original design as-is except for removing the stacked intakes. It may work.

[endl]

the issue extends beyond this one design, first some of the mods im using aren't properly shielding parts against far destruction forces. secondly i wanted to try some even crazier designs like a vtol where the engines are on the inside of the fuselage and the fuel is on the outside, not really talking about part clipping just sort of a plane turned inside out. look up the oyster to get a better idea of what im talking about.

[Hodo]

I have built VTOLs that work in FAR, like this monstrosity.

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Or this little thing.

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Both worked fine in FAR. The problem is you have to many intakes, in FAR you don't need to air hog, it just doesnt work.

[endl]

I have built VTOLs that work in FAR, like this monstrosity.

Both worked fine in FAR. The problem is you have to many intakes, in FAR you don't need to air hog, it just doesnt work.

i realize that air hogging is unnecessary in regards to the design i posted, but when i was talking about a vtol i was talking about making something like the following wouldnt work in FAR, but damn is it a cool idea

[Hodo]

i realize that air hogging is unnecessary in regards to the design i posted, but when i was talking about a vtol i was talking about making something like the following wouldnt work in FAR, but damn is it a cool idea

You could still do something like that but with more of an eye to realism.

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I made that last version of KSP, it was the beginning of a test line that I was messing around with. I never really kept refining the ideas and just let them drop after a while. But it is possible to do those things, it just takes more work then initially thought.

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These little things still can achieve orbit, and they are quite small.