Official FAR Craft Repository

[Hodo]

 

23 hours ago, SimGuLiM said:

F-15

The plane is a bit nose heavy, suggestion are appreciated

 

The F-15 is a bit bulkier than that design.  You have a lot of wing compared to the real F-15c Eagle.  And this is actually mostly behind your actual CoM.  I would suggest making smaller wings, getting rid of that cockpit, the intakes on the F-15 are MASSIVE compared to the airframe. 

Edited January 5, 2016 by Hodo
Part of the reply was no longer relivent.

[kcs123]

Since there is no good enough hovering autopilot for KAX, I created one with kOS autopilot scripts. You no need to know too much about kOS to be able to use hovering autopilot. Album shows enough how to run this script, after that just enjoy in flight. Both, craft example and kOS script can be found in thread linked in my signature.

Hovering autopilot can be also useful for VTOLs with jet engines, although it does not do thrust balancing, you will need to do that on your own trough careful and balanced craft design. With some modification to script it could be used for plane landing assistance too.

This is my first usable kOS script, so don't be too harsh on me with feedback. Enjoy.

 

[Wanderfound]

Kerbodrone

 

 

Craft file at https://www.dropbox.com/s/k7p8b3cmue12ed1/Kerbodrone.craft?dl=0

Leave 20 units of LF tank empty if you want to give it a bit more orbital fuel margin.

Edited January 6, 2016 by Wanderfound

[SpaceToad]

On 12/20/2015 at 2:35 AM, tetryds said:

@cantab analyzing your craft I have noticed some  things that may be important.
First is that you have way too much dihedral effect, your wings have a big sweep angle and are above the center of mass, I recommend sweeping them less as that is affected more by speed, moving them lower or angling them down would only solve the instability for slower speeds, where you don't seem to be having problems.
Then, you are going to need more vertical stabilization, if you cannot make your vertical stabilizers higher the only option left is making them longer, and further back from the center of mass.
In fact, you may want to extend those vertical stabilizers a bit far behind the craft, making it behave like a lawn dart on the yaw axis.
If you are going to keep the sweep angle as it is, I heavily recommend changing that nose, blunt noses are only good for on hypersonic to bend the shockwave, which would not matter much in this case, go for something more pointy.

Just curious, is there a guide out there on how to analyze aircraft in FAR and make changes to get desired results? Where did you learn so much about aerodynamics?

Also, where the heck are the tips in your signature? The link just takes me to the front page of a competition. I assume its in there somewhere, but I don't have the time right now to look for it myself. (I'm at "work")

Edited January 6, 2016 by SpaceToad

[Hodo]

20 hours ago, kcs123 said:

Since there is no good enough hovering autopilot for KAX, I created one with kOS autopilot scripts. You no need to know too much about kOS to be able to use hovering autopilot. Album shows enough how to run this script, after that just enjoy in flight. Both, craft example and kOS script can be found in thread linked in my signature.

Hovering autopilot can be also useful for VTOLs with jet engines, although it does not do thrust balancing, you will need to do that on your own trough careful and balanced craft design. With some modification to script it could be used for plane landing assistance too.

This is my first usable kOS script, so don't be too harsh on me with feedback. Enjoy.

 

That is pretty awesome.  I love the fact you programmed in something from KOS to get that to work.

I instead went with a different approach.

 

 

18 minutes ago, SpaceToad said:

Just curious, is there a guide out there on how to analyze aircraft in FAR and make changes to get desired results? Where did you learn so much about aerodynamics?

Also, where the heck are the tips in your signature? The link just takes me to the front page of a competition. I assume its in there somewhere, but I don't have the time right now to look for it myself. (I'm at "work")

There is, somewhere.... If I were at home I would be able to give you the link. 

 

But most of us learned about aerodynamics from either reading books or in my case, studying videos on Youtube.  It is amazing how much you can learn from those old 1960s and 70s supersonic instructional videos. 

[kcs123]

50 minutes ago, SpaceToad said:

Also, where the heck are the tips in your signature? The link just takes me to the front page of a competition. I assume its in there somewhere, but I don't have the time right now to look for it myself. (I'm at "work")

Links in signatures and various forum post have become broken after forum migration. Some of links were updated properly after migration, but for some of them each user have to edit post and repair links.

Anyway, I have collected some tips from various pages and combined that with my own game expirience. You might want to check link in my signature.
Also, Wanderfound have usefull tips in his craft exchange thread too, you might want to read tips from various authors and use best tips from each.

EDIT:
If you didn't already, check out Basic Aircraft Design thread too, it is old post but realy a good one before building your own craft.

Edited January 6, 2016 by kcs123

[SimGuLiM]

On 5/1/2016 at 5:06 PM, Hodo said:

 

 

The F-15 is a bit bulkier than that design.  You have a lot of wing compared to the real F-15c Eagle.  And this is actually mostly behind your actual CoM.  I would suggest making smaller wings, getting rid of that cockpit, the intakes on the F-15 are MASSIVE compared to the airframe. 

lot of time i have the same problem also with other planes:
if i move the wings forward near or on the CoM, the plane is balanced but if i pull full up, the turn is not fluid, maybe cause the wings stall and fly, stall and fly...
than, can u suggest a cool cockpit mod
thx

[Hodo]

3 hours ago, SimGuLiM said:

lot of time i have the same problem also with other planes:
if i move the wings forward near or on the CoM, the plane is balanced but if i pull full up, the turn is not fluid, maybe cause the wings stall and fly, stall and fly...
than, can u suggest a cool cockpit mod
thx

Honestly there are several options for the F-15 cockpit, even stock.  The stock cockpit works if you build to scale. 

[Wanderfound]

A challenge that should test your transonic drag tuning abilities: http://forum.kerbalspaceprogram.com/index.php?/topic/129749-junoracer-challenge/

 

 

[Wanderfound]

Aerobatic demonstrator:

 

 

Craft file at https://www.dropbox.com/s/gayfy6bzd9tvcwa/Kerbodyne%20Dancer.craft?dl=0

[Guest]

new plane flies very smooth

[kcs123]

Long Range J33-J20 VTOL

Long distance field research doesn't have to be tedious with right craft design. Small craft that have a lot of fuel in tanks might not be able to take off fully loaded, but once you reach distant spot, fuel will be consumed and you will be able to take off vertically too. Might not look on the first sight, but craft actually have quite low drag. Such low drag allows supersonic velocity over 1 mach with single J33 engine that was originally not even designed for supersonic flights. For that reason you can't fly long on high speeds due to overheating, but 0.80 or 0.90 mach can be sustained for longer times. Stable craft design also allow maximum time acceleration without issues. That makes this craft a good choice for science exploration early in career. Because it is early trough SETIctt career, front landing gear might look odd compared to light adjustable landing gears but serve purpose well enough.

 

[Matuchkin]

How do you guys do this?

HOW?

HOW?

[kcs123]

4 hours ago, Matuchkin said:

How do you guys do this?

HOW?

HOW?

With patience. Trial and error. It become much easier on each new craft design, but first huge step in design process is to understand tools that FAR provides.
I don't publish each designed craft, only those that could be used as good example and interesting for others.

[Paul_Sawyer]

I was going to make a scientific airplane to go to the pole to get some science for my career, but it suddenly turned into some kind of Eurofighter Typhoon, and I had to abandon the pole idea. So, well, no science for today, but at least the KSC is under protection now :).
 

 

Edited January 30, 2016 by Paul_Sawyer

[sashan]

Kan-28 Sapsan.
Made this fighter when I needed something part-count light and with decent flight characteristics for all those BDarmory battles.
It's powered by custom "F-100" 0.625m afterburning jet that I've made using old Ven's stock revamp model for Turbojet.  The model was too good to let it go waste after Porkjet's part release.
*Sapsan is a steppe hawk that inhabits southern part of Ukraine.

It's just 53 parts, which is IMO great - I can have two of them on one side and two similar ones on another without large lag.

 

How do you share imgur album in this new forum engine?

@Paul_Sawyer Can you share the craft? It's really good and I have all required mods.

Edited February 2, 2016 by sashan

[Paul_Sawyer]

@sashan, sorry for late response, I missed your post somehow.
Here you go, newest modification:
https://www.dropbox.com/s/xpcj3dzmrdwr5ke/Eliot%20F-1%20-%20Crusader%20C2.craft?dl=0
It's quiet responsive to controls, so careful on those aerobatics

List of mods, just in case:

• B9 Procedural wings
• Adjustable gears
• TweakScale
• FAR (obviously)

P.S. Concerning imgur albums - there is a button on toolbar, black square with letter "i".

Edited February 2, 2016 by Paul_Sawyer
just to add some stuff

[Doke]

So, I've been playing around with a bunch of sketches based on supposed design concept pictures for an 'LFI', a Russian light fighter proposal from back in the '90s (IIRC). A couple were basically Eurocanards, which I find a bit boring, although the Yakovlev one has a nifty cranked delta and interesting lines. Two ideas that really jumped out at me: a Mikoyan tailless semi-delta (not sure what else to call it), and a Sukhoi which was basically a single engined, kawaii flanker with canards. I attempted to make both.The MiG didn't come out quite the way I intended, but it's fast, if a little ugly. I decided it would make a good ground attack plane. The Sukhoi, though, is awesome. It ended up with a much more blended body than the original, partly because I wanted to see what I could get away with using B9 procedural parts. I also ditched the canards, which didn't seem to add anything.

Links:

Crow (flankeresque), armed.

Crow, unarmed.

Magpie (weird delta thingy).

All designs use B9 Procedural Parts and Adjustable Landing Gear. The armed Crow and the Magpie also use BD Armory.

[edit] Nothing I do will make imgur work, and I'm tired of fighting software today, so you'll all just have to download the planes to see what they look like. I promise the Crow is worth it.

[edit edit] All fixed. Thanks @tetryds, I was just tired and couldn't remember how to do albums.

Also, if anyone does download the planes and is using DD, the Crow is set up for it but has very conservative settings. You can afford to be a lot more aggressive with the controls than I've allowed.

[edit edit edit] Just realised the 'unarmed' Crow had a flipping BD radome. All fixed now.

 

Edited February 6, 2016 by Doke

[tetryds]

@Doke Try clicking the imgur image so that it shows the image link, with a .png/.jpeg on the end, like this: http://i.imgur.com/qQhY2Wi.png

Then just press Enter twice and your image will appear

I don't think people will download your airplanes without pics for them, so you can edit the images in.

If you need more help or it still does not work, please contact me and I will assist you.

[Elthy]

This may be the right place to ask...

I have some problems getting a craft inspired by the venture star SSTO flying properly:

Here you can see it fly decently, nothing bad happens as long as i dont try to roll/yaw. Then this happens:

This is without any controll input other than a light nudge in roll or yaw. As you can see both spaceshuttle fins apply a rotational force in the same dircetion. Without seconds the craft is tumbling out of controll without any chance to recover it. This happens at high subsonic speed, but i remember haing that issue at higher speeds, too.

Some details on the craft:

Im using lots of tweak-scaled parts, due to some edits in parts the whole thing wheights only 80T empty (thats how im testing it). Im using the most recent FAR and a rescaled kerbin (factor 3.2).

Edited February 6, 2016 by Elthy

[kcs123]

@Elthy, It is hard to tell without pictures of FAR stability derivatives on velocity/altitude where you noticed problems.

But based just on presented pictures, there is couple of things that you may try. Larger vertical tail surfaces - it is not enough for plane of that weight and length.

More wingspan for main wings, try to place them in a way that outmost wing tip is close to COM, just behind it works wonders for roll stability.
Less dihedral angle. Dihedirial angle on main wings help with roll stability, mut it seems you have too much. Small vertical surfaces on wingtips can also help with both - more lift from wings that have same wingspan and more roll stability.

Overall craft length and weight might be too much for just small delta type wings on that craft. Consider design with main wings in the middle of hull with help of small canrads in front and some elevators on tail, it might be easier to create good craft that have similar shape without increasing wingspan too much.

Also, consider doing opposite than you already did. Put some payload in craft rather than design it with empty cargo bay. Try to put paload in a way that it does not influence shifting of COM trough length of cracft. Small  COM changes in up/down will not influence much in design process. That way your craft will be more than capable for stable craft while empty and you will have much less trouble with different sized payloads - craft wingspan will be apđropriate for chosen payload.

[Elthy]

Thanks for the tips, ill try them soon.

The payload is not relevant for atmospheric flight since this thing is designed as a reusable upper stage, it will only fly in the atmosphere without fuel/payload (or on a big booster).

Edit: Now its flying way, way better! I made those tail surfaces 50% bigger (i love tweakscale), lowered the dihedirial angle of the main delta wings while placing them a tiny bit forward, also i added small vertical controll surfaces on the wingtips. Those add outward facing yellow arrows while in flight, whats the meaning of that?

Now to hypersonic testing in the upper atmosphere...

Edited February 6, 2016 by Elthy

[kcs123]

3 minutes ago, Elthy said:

Thanks for the tips, ill try them soon.

The payload is not relevant for atmospheric flight since this thing is designed as a reusable upper stage, it will only fly in the atmosphere without fuel/payload (or on a big booster).

And how you plan to put it in orbit ? Even with shuttle style vertical launch/ horizontal land, payload have a lot of influence. More than you might think. And it also helps a lot to determine right wingspan for given overall weight. Anyhow, have some fun with craft design.

[Elthy]

It wont launch like the Shuttle, but on top of a Falcon 9 style first stage. So the payload will allways be in the line of thrust. It will be interessting how the rocket will behave with such a wide, high drag upper stage, but thats a problem ill deal with when i can safely reenter from LKO...

[kcs123]

1 hour ago, Elthy said:

Those add outward facing yellow arrows while in flight, whats the meaning of that?

That is torque. In few previous versions those were turned off by default, perhaps ferram forgot to disable those for release.
In stable flight there should not be any. It might be sign of unstable craft design, but on the other hand, it is normal to see hose in certain flight condition.

It is kind of hard to explain meaning of "good" and "bad" visualisation when comes to torque, that was probable reason why ferrram disable torque visualisation in previous versions - to be less confusing for people who does not understand meaning of torque forces.