nitrosportsandrunner

ive flown a parkzone slo-v, hobbyzone super cub, then a dynam 4ch cub and a Funjet pusher flying wing.

I didn't fly at all last summer, cause I didn't have money to buy a plane. my last plane, the dynam, I flew for 2 summers. it is a great plane for the money and it held up well to many crashes as I learned to fly a 4ch.

now I have parts from the dynam and the funjet. and I started watching the Flite Test guys on youtube and how they build stuff out of $1 foam board.....so I went out and bought a bunch.

I tried to think of the easiest, strongest, yet most agile airframe to build. to me, that means a flying wing...similar to the funjet. the simplest to build is a 3ch, and a V-tail mixing wing would be the most agile 3ch IMO.

so, with very little knowledge and absolutely no skill, I started building a airframe.

heres what I have so far:
30'' wingspan
4'' tips
20'' long

I haven't cut the control surfaces yet, but you can tell where they are. ill have a 1/4x1/4 stick placed down the center in the same area as the fins which will be the motor mount (the dynam's motor has a odd mount, it doesn't flush mount)

before I mount any electronics, I am going to go out in a field with some penny's and tape and toss the plane and add weight until it glides. this should help me figure out the CG. then I can add the electronics and adjust them around as needed.

I think I will cut a large rectangle down the center section, threw the top 3 layers, so that the electronics and battery can sit down in the airframe at least half way.

this may be a total flop, but even if it does I will hopefully learn something for the next attempt.

jester_s1

You've come across one of the most fun ways to enjoy the hobby, which is to try new ideas and mess with things until they work. Looking at your design, I think your elevons are too big and your vertical is too small, but you'll know that soon enough when you fly it. For a truly easy plane to fly, have a look at the proportions of an ugly stick. Nothing is more forgiving, and the agility can go way up if you want it to. Flying wings are more about speed than ease of flying.

JohnBuckner

My Feedback: (1)

Yup, yup The pitch glider technique is the oldest method of all of finding the proper CG and loads of fun without computers. I too feel that your elevons are to large and would work better at about half that chord (depth).

Just so you will know in your first post you called the control surfaces a "V tail mixing wing" but when you start installing your radio system what you have there are elevons and you need Elevon mixing ability with your radio and not V tail mixs, perhaps this will save you some confusion later.

Enjoy

John

nitrosportsandrunner

a V tail and a flying wing don't use their control surfaces in the same manner? with a V tail to go up or down the surfaces go in the same direction. and to turn they go opposite direction. doesn't a flying wing do the same???


I haven't actually cut the control surface hinge yet. I was planning on making it 1'' wide. if you mean the length is too long, I may do 2/3's of available area.

I had decided before going to bed last night that I will re-do stabs, making them bigger.

j.duncker

My Feedback: (2)

Yup you need to double the fin size. Here is my similar balsa home brew.

jester_s1

No, v-tails don't work the same way. In a v-tail, the tail controls yaw and pitch. With elevons, it controls pitch and roll. The concepts are similar in that you are accomplishing dual functions with the same two surfaces, but the programming is totally different. Nearly every transmitter that has v-tail mixing also has elevons though, so you should be fine.

nitrosportsandrunner

my trans is a standard 4ch, no mixing functions. I have a stand alone V tail mixer (servos plug to that, then that plugs to rx)

I didn't realize the programing was different. I did know that the function differs as the controls on the wing roll and then up to bank, as apposed to a v tail in which they act more like a rudder than ailerons.

ill have to dig threw my stuff. I did have a radio for the funjet, but I may have sold it.

JohnBuckner

My Feedback: (1)

A stand alone V tail mixer or a V tail mix in your transmitter just will not work. What you need is a Elevon mix. What a V tail mix does is mix elevator and rudder functions and it actually operate what are sometimes called ruddivators. What you need is to mix the ailerons and elevator and of course they are now called elevons.

There are two other ways to avoid the use of any mixes on your airplane and the first I do not suggest as it calls for some rather intricate building skills. This method is actually a complete mix done mechanically with no electronc magic at all. It actually involves mounting one of the two servos on a slider and the second servo moves the first. I still have an airplane that uses this method, called a Scimitar. Agine I do not recommend this methods as it is rather time consuming to do.

Now last but what I would do myself lacking an electronic elevon mix and it works quite well. To do this instead of just using two control surfaces add a third and one more servo for a total of three control surfaces and three servos. Frequently when this is done There are three surface equally spread across the trailing edge of the wing however with the configuration you want to use the elevator is easily placed between the vertical fins that you already have shown. It would only be necessary to place the vertical surfaces further apart to provide enough area for the horizontal stabilizer (fixed portion) and the moving elevator itself.

Just some thoughts for you to peruse.

John

nitrosportsandrunner

I pulled out my electronics, hooked up the v tail mixer and checked out what the servos do.

I don't see why it cant be used on a wing. move the elevator stick, both servos move the same direction. move the Rudder stick, servos move in opposite directions. moving in opposite directions would cause the wing to roll. granted, this id done threw the rudder stick and not the aileron stick, but the effect should be the same. granted, some mixing happens and it will try to both roll the plane and yank it at the same time, but if you keep the stick moving on the axis (+) then it would roll or elevator...not both at the same time. I could swear that is how the funjet would operate!

I think I get the second option you describe, using three servos. 2 operate 2 separate surfaces as the ailerons....the 3rd controlling a elevator surface between the fixed stabs. I might consider that...but I like the idea of a 3ch wing needing only 1 stick for direction. that's what im used to for 3ch planes.

nitrosportsandrunner

I wrote things wrong above^^^
I have the right stick controlling both aileron and elevator. before I said I moved the rudder stick, I meant aileron stick. its been a while since I flew anything and forgot the rudder is on the throttle side.

JohnBuckner

My Feedback: (1)

If in fact you fly the more common (in this country) mode two which also would indicate a minimum four channel two stick radio and you used any appropriate elevon mix then the up/down and right/left will both be on the right hand stick. The throttle will be on the left hand stick.

If you attempt to use an inappropriate V tail mix then this will not be the case, it won't work.

Now yes if you wish to avoid any of this then using a three control surface wing you will not need any mixs whatsoever.

V Tail mix mixes elevator with rudder ( V tail is only used for full house airplanes with controls on all three axis not on airplanes that only control two axis) the most common type to use this are high speed pylon racing airplanes.

Elevon mix mixes elevator with aileron


John

nitrosportsandrunner

I guess im still confused...
my V tail mixer is connected to my aileron and elevator channels. it is not connected to the rudder channel.
I do use the common mode 2, throttle and rudder on the left....elevator and aileron on the right.

I might finish this airframe and put it on the shelf, then build a typical airframe with elevator and rudder.

JohnBuckner

My Feedback: (1)

OK it must be something like the old Christy mixer so if it works then great go ahead and use that puppy I should have confined my statement indicate it won.t work when the mixing is done in the Transmitter.

John

nitrosportsandrunner

ah I see.
I also just looked up the mixer I have, here it is on ebay:
http://www.ebay.com/itm/HobbyWing-RC...#ht_1851wt_886

Instructor

My Feedback: (16)

Have you used this mixer on a flying wing? I have used the one from Du-Bro. It requires two servos with one driving the ailerons and the other servo driving the elevator. Just thought I would throw this out there for you.....

Larry / Instructor

jtotten

There are a number of web sites that have plans or blogs on planes in your size range. Here is a link to one of them:

http://rcfoamfighters.com/blog/?cat=11

JohnBuckner

My Feedback: (1)

http://shop.dubro.com/p/v-tail-mixer-qty-pkg-1

This is the Dubro mixer that Instructor mentioned above. It to is a variation of the mechanical mixers, This one instead of having one servo move the second servo in a slider it uses a rocker for one servo to move the output arm of the second servo.

John

stevegauth30

I was just going to tell you about rc foam fighters when I saw that someone else brought it up. I've built a couple of there planes with great results. And the plans are free to download off there website. Good luck with your venture. I hope you have good luck and become a master builder.

CafeenMan

The comment was made the deltas are more for speed than ease of flying.

Every delta flying wing I've built was incredibly easy to fly. Like any other kind of airplane you can build it to fly fast, slow or somewhere in between by controlling the weight and choosing an airfoil thickness that provides the speed range you want.

JohnBuckner - why do you think v-tail mixing won't work with elevons when mixed in the transmitter? It will default to ailerons being the left stick but a lot of transmitters will allow the rudder to be mixed to the ailerons so that you can use either stick at the same time.

In fact, I have a three-channel plane that either rudder or aileron moves the rudder because I tend to fly differently with each hand. Thus when I'm thinking rudder correction I move the rudder stick and when I'm thinking aileron correction I move the right stick.

Obviously that's just a psychological thing since they're both moving the exact same control exactly the same way.

Of course if the transmitter is high end enough an elevon mix will be built in or a V-tail mix can be used with rudder assigned to the aileron stick.

Did I miss something or are you saying it won't work because it will be on the wrong stick?

CafeenMan

nitrosportsanddrunner - usually the best kits for a first time builder are either a Proctor Nieuport 28 or a Proctor Jenny. Either can be built in a couple afternoons.

stevegauth30

Yeah, that'll work. Lol.

CafeenMan

I just want to help steer new guys in the right direction so they don't get frustrated and quit.

stevegauth30

Are you talking about the big 1/4 and 1/3 scale proctor kits? With the aluminum tube frame? There's got to be another proctor kit that I don't know about. I didn't mean that other post rudely, by the way, I thought it was a joke. I'll google proctor nieuport 28 and see.

stevegauth30

All I find are the giant museum scale kits, which aren't all aluminum tubed, only some.

CafeenMan

You were right the first time. I was joking. Still not bad kits to have to look forward to building one day.