Well today(this morning) is the day I realized making a VTOL with FAR is difficult.

[How2FoldSoup]

Does anyone have any tips on this? I'm almost perfectly balanced but unless I am moving in a direction I tend to immediately stall due to far and just explode as usual. Other than perfectly balancing out the vtol engines are there any other techniques to a workingâ„¢ vtol?

Edit:

Okay - Apologies for the lack of details this morning Kerbal Engineers who had been experiencing the problem were influenced by spiked eggnog in lieu of the upcoming Holiday, Halloween. Due to their less than sober nature they were did the explain the issue very well or to its greatest extent in detail.

So here's the problem: I have the thrusters balanced quite well over the CoM(The plane still looks very sexy and like an actual plane) but the problem is that I run FAR. When I'm cutting my horizontal speed to do a pure VTOL landing FAR recognizes this as low airspeed and stalls me...which causes me to lose control. Expert kerbin test pilots managed to land it once but it was more a short landing where the thrusters slowed me down at an angle to where my horizontal speed was not very high but still fast enough to generate lift(according to FAR) and have a soft rolling touchdown.

My question: Is there a solution to FAR not stalling you when your horizontal speed drops below its stall threshold? Just to reiterate the issue I am having is that FAR is stalling me because my airspeed is too slow when I'm landing vertically.

Second edit: I received a response on the FAR mod thread saying that it's the angle of attack that will determine if you stall or not just in case anyone is wondering. So as long as you stay roughly +-5 off the horizon you should be good to slowly descend with the mod

Edited October 11, 2013 by How2FoldSoup

[Kasuha]

Active SAS and lots of torque?

[How2FoldSoup]

I thought about adding more torque mods but it just doesn't fit within the plane aesthetically which I'm really trying to keep. Believe me I've got the sas on It's tough testing it on kerbal I seem to be pivoting back and forth between thrust being too far forward or backward and I'm not sure where to go from here.

[G4S3FR]

It's imperative that your centre of mass is almost perfectly centred, making a VTOL look like an actual plane in KSP is quite dificult because of centre of mass issues.

[How2FoldSoup]

It's imperative that your centre of mass is almost perfectly centred, making a VTOL look like an actual plane in KSP is quite dificult because of centre of mass issues.

I do not have the CoM centered but I have the VTOL engines centered around the CoM almost perfectly so that it almost stable on liftoff. I seem to be able to fight it into the air and in an angle that I need to just be able to take off(which is all I want from it) but I can't seem to manage a perfectly(or near) vertical landing which is what I'm after.

Edited October 11, 2013 by How2FoldSoup

[Xiphos]

I built a VTOL plane, and the slowest landing I could manage was 4m/s horizontal speed. Even then the dance of stall vs not stall is tricky to say the least. I can upload the craft file if you like, it looks a lot like the F-35, which is what I was going for. Bascially you need to come in fast, and blast your vertical engine and cut your horizontal engine and flare big time. Coming in low helps because you will gain altitude here. Then level out and decrease throttle. Of course you could always cheat and put a set of chutes on it...

[How2FoldSoup]

I built a VTOL plane, and the slowest landing I could manage was 4m/s horizontal speed. Even then the dance of stall vs not stall is tricky to say the least. I can upload the craft file if you like, it looks a lot like the F-35, which is what I was going for. Bascially you need to come in fast, and blast your vertical engine and cut your horizontal engine and flare big time. Coming in low helps because you will gain altitude here. Then level out and decrease throttle. Of course you could always cheat and put a set of chutes on it...

I was attempting to avoid just that 4m/s is a lot better than I can do! The slowest I can do is touchdown at ~40m/s. Do you have FAR installed? if so how do you deal with FAR's stall factor with 0 horizontal speed? Granted I am not attempting an F-35 but a 135 ton cargo plane.

[Xiphos]

I do not have FAR installed, so I can't say but it might be worth it to try your design stock as it might work better. Also, my vertical engine is on the thrust centerline, right under the center of mass, with both fuel tanks draining into it. But when you fly with the horizontal engine, it uses fuel from one tank so you must balance before you attempt a landing. Also, put canards on the nose as this will greatly help your slow speed/high alpha characteristics. And it's very very hard to get your horizontal speed to 0 as you will be trying to input throttle changes, pitch, roll and yaw corrections. I wish this game allowed us independant controls of the canards, as I believe a true 0m/s landing is possible that way

Edited October 11, 2013 by Xiphos

[How2FoldSoup]

Ahh okay. I may have to do this stock but I enjoy FAR so much. It's a nice challenge. Your post made me think of the center of thrust about my vtol thrusters so thank you very much! I made a test file and took out my normal engines but marked where the CoM was so that I would be able to line it up. I'm very close now. I'm know precisely 0 would be difficult enough I'm just trying to get it to the prettiest landing I can. I do also have a wing up front on the nose too but I did not about that it helps slow me down so thank you again. You helped a lot! I think it's just experimentation now to perfect the design.

Edit: FAR stalling me is still a huge problem..I can be 200m above the ground and slowing down to ~30 m/s but FAR will stall me so I "lose control" and begin to roll as if I were flying and stalling

Edited October 11, 2013 by How2FoldSoup

[Xiphos]

Yes, by all means it takes a lot of experimenting to get it down to pretty landings. And every plane is different. When I first built the plane I would take off vertially, and go up a few meters, try to hover, then land back down. This should give you a good feel for the plane around the stall point. Also, I'd like to see your design I'm very interested in a cargo type VTOL

Edited October 11, 2013 by Xiphos

[How2FoldSoup]

Sure thing ^^ I have a few mods installed...B9, infernal robotics, FAR, pWings, and TAC fuel balancing(It really helps with the problem you mentioned about your plane, this thing is impossible to use as a vtol without it).

I left to eat breakfast and I came back 20 minutes later to find that my plane had migrated over to the KSP main building so I figured why not try to land on it...(I am too lazy to close the baydoors on testing)

I present the Ostrich Pizza Delivery Plane

I got close but my VTOL flying skills are still green so I lost control and crashed some distance away but it was a fun try! I got an answer on the FAR thread saying stalling is about AoA so I'm going to go through some more test flights with a lower AoA.

If you're interested in better(not in action) pictures of the ostrich I have an old version of her in this album.

http://imgur.com/a/DLCOV#0

This is pre-VTOL and a couple other surprises she can do ^^

With the version you see above she can reach ~100km orbit with about 1500 dv left without cargo.

When I lifted the orange tank in that album I believe I had about 500 dv left after circulation and still a few hundred dv in the tanks when I docked.. I swapped the jet engines to sabres so I could use the Ostrich on other planets which is why VTOL/STOL is necessary for Duna and the like.

Edited October 11, 2013 by How2FoldSoup

[Xiphos]

HOLY CRAP that plane looks freaking awesome! My jaw dropped haha. Excellent work there. Makes my VTOL look like 1st grade haha.

[How2FoldSoup]

Thank you very much! I've put a lot of work into her over time. It's been my pet project The first goal is to land her on Duna with a Kethane rover/extractor so I can top off the tanks and come home...I think she can do it.

Here's another screenie of her I just took buzzing the tower

Jeb:"This is OstrichRider requesting a flyby"

Bob:"Negative OstrichRider the pattern is full"

Jeb and Bill up to no good again

Looks like Jeb is flying a cargoplane filled with rubber dog...toys...

P.s. It's the mod parts that make it look so beautiful - Im assuming you run stock and it's harder to work with stock parts and make something beautiful and functional so more power to you!

Edited October 11, 2013 by How2FoldSoup

[asmi]

So here's the problem: I have the thrusters balanced quite well over the CoM(The plane still looks very sexy and like an actual plane) but the problem is that I run FAR. When I'm cutting my horizontal speed to do a pure VTOL landing FAR recognizes this as low airspeed and stalls me...which causes me to lose control. Expert kerbin test pilots managed to land it once but it was more a short landing where the thrusters slowed me down at an angle to where my horizontal speed was not very high but still fast enough to generate lift(according to FAR) and have a soft rolling touchdown.

My question: Is there a solution to FAR not stalling you when your horizontal speed drops below its stall threshold? Just to reiterate the issue I am having is that FAR is stalling me because my airspeed is too slow when I'm landing vertically.

Second edit: I received a response on the FAR mod thread saying that it's the angle of attack that will determine if you stall or not just in case anyone is wondering. So as long as you stay roughly +-5 off the horizon you should be good to slowly descend with the mod

I think you don't understand what exactly stall means. It means two things. First - your aerofoil doesn't produce any lift (which is kinda expected since it doesn't move laretally and therefore there is no airflow around them that creates lift). Second - your aerodynamic control surfaces don't work (which also makes sense if you recall that they work by manipulating the airflow around them, when there is no lateral movement, there is no airflow). BUT - it doesn't mean you lose control - if you have other means to control (like ideally balanced VTOL engines, or RCS), you'll be just fine. Since ideal balancing is next to impossible, RCS is often use to compensate for small imbalances. In real life it's compensated by differential thrust of engines and/or by thrust vectoring, both of which are kinda hard to do in KSP (although I seem to recall that there is a plugin to do just that), so using RCS sounds like a good way around...

[How2FoldSoup]

I do in fact understand exactly what a stall means and how lift works. I believe you misunderstood my initial post. Had this been a post about an R.C. Plane I was making in real life I would say you're right. The problem lies that this is kerbal and unfortunately it is not the most realistic simulator In stock kerbal lift works simply; If you have enough lift compared to the weight of your craft you will fly. You can search for videos of snake craft and the like doing just that. Since I enjoy challenges and planes are my specialty in general I opted to use FAR. How FAR works is as I said in my second edit. FAR determines your horizontal speed and compares it to your AoA. If such is that it does not agree with FAR's algorithms it deems that you are "stalling" and flips you to one side or otherwise lose control. Since this is a video game and not life, actual airflow does not really have an effect. Unfortunately the lack of laminar flow creating a low pressure bubble above the wing to create lift just doesn't happen in kerbal . I was speaking in terms of kerbalogy as opposed to real life. If you look at my pictures you'll see that I do have the vtol engines balanced in addition to using RCS. That is not the problem. The mechanics with FAR and kerbal is. I have created a solution that just requires a different style of flying when landing.

Thank you, however, for your reply

P.S. If you're interested in seeing what I'm talking about I could create a video for you. It's quite simple to reproduce.

[Hodo]

VTOLs are very possible in FAR, here is my most successful. It has been to Minimus and back.

And here is my knew crew shuttle VTOL.

The best bit of advice I can tell you is, you have to do a VERY controlled slow down to your stall speed, and make sure that you are already in VTOL mode at that point. Otherwise you will do all crazy stall flipout. You can put small thrusters or Air RCS found in the B9 pack on the tips of your wings to help with this problem or more SAS systems.

It is really frustrating and trying to say the least, but it does work. I am still working on VTOLs to make them better, and I am still making them better on my end.

Edited October 14, 2013 by Hodo