a088008

Thanks for the compliments. I'll be finnished with the covering in a day or two. The compound curve on the wingtips was a nightmare to cover. I'm glad that's over with. So there are more pictures coming.

About the SR-71 pitch control issue. I was thinking today and it hit me. Essentially I wanted to have a lifting body that acted like a canard, but there are no pitch control surfaces up front, as is the case with a canard. So, I thought, what if I put a pitch control surface up front. This would stop the tendancy of the model to pitch up and stay up despite "down" elevon.

I've attached a picture of what I'm proposing. I don't know how pitch sensative this arrangement is going to be since the forward pitch control is really a reverse elevator i.e. the hinge line is at the back of the elevator. It should however provide a way to control the lift produced by the nose.

What do you think?

-Q.

William Robison

My Feedback: (3)

a088008:
Sir, that is a guaranteed crash. Prove it to yourself by holding 4x12 sheet of balsa in your hand, as you drive at 35-40 mph, out the window with the sheet in front of your hand. When you feel how much power it takes to hold it flat into the wind you'll drop the idea.

Now if you put two small booms forward at each side of the nose, and pivot your canard 1/5 to 1/4 of the way back from the leading edge you could use a link to your elevator servo to operate it, or it could be your only elevator.

But never pivot a control surface behind the aerodynamic center, if you want the second flight with the airplane.

Fly twins, they're fine
. To keep you of sound mind.

Bill.

a088008

I must confess that I had a good chuckle when I read your reply. I was waiting for someone to point out this obvious flaw, UNLESS the "reverse" elevator has a suffiently small cord. I was thinking between 1/4" and 1/2" cord. The trick would be to find a cord small enough to create an effect without getting a force keeping it deflected with sufficient power. Ah, scrap the idea.

If I am to place a canard-type control surface at the front I'll do it the conventional way, as you suggested.

-Q.

MR Flyer57

Your design has really raised a lot of interest in the group.

I think I would just try it as designed. If it becomes too much to handle you will know during your gliding and CG tests.

Who knows, it may fly like a dream. Start slow and if it gets beyond the control limits hang it in the living room and make another with canards. Or you might add them to yours.

I think the Wright Brothers had a control surface in front, a little like the one your thinking of.
It might work if you don't have too much speed.
Marshall

a088008

It's nice to see so many people input there ideas into a project. I really like working on new and un-tested stuff, so there will undoubtably be many more designs for you guys to chew the fat over, in the future. I have a VERY contraversial design coming up sometime this year. I have seen mention of something similar to what I've designed, but I've taken it to the next level. All I'll tell you is that it's not a conventional planform and it might shake up the weight-lifting competition world a bit. It's just a pitty that I will not be able to enter the design in a formal contest. Maybe a demo flight, though. Now, I said sometime this year, because my idea is still in the "napkin" phase.

I've decided to fly the "Adrenaline" plane as-is and see what happens. If there are problems in glide tests then I'll consider a canard-type control surface under the nose of the plane. This way I can keep the lines clean and keep the control surface safe from those nasty nose-in landings (the front landing gear will protect the nose and canard control surface). I'm know for my landing techniques - or lack thereof. I think it's a depth perception thing, or maybe I'm just blind and nobody has bothered to let me know.

The Wright Bros knew the thing or two about aerodynamics, even in those days. They overdid it on the lift of their machine, much like what I'm expecting from my design, but it flew. I hope I can emulate their success.

-Q.

a088008

I have a question on control throws:

I'd like to calculate what control throws will acceptable for "Trainer" type pitch flight characteristics based on wing area and and elevator area and possibly including wing cord and CG in the equation. I'm guessing that the equation would calculate the pitch moment at the hinge line of the elevator. Anybody got an idea of how to calculate this?

-Q.

Bish Wheeler

Very interesting design ......but it won't fly, at least not very long. It has got to have conventional canards. I can't get a handle on how big the plane is. Thinking really small, but what is the WS. Love that you are "doing' it.

Bish

a088008

Hi Bish.

It has a 50" wingspan and the body is 19" (excluding fins). The wing area is 384 sq.in. and the dry weight of the structure (no covering or radio gear/battery/motor) is just less than 6 oz.

Thanks for the support (I think ) I will be testing this weekend and should have some glide and possibly flight test results very soon.

-Q.

imsofaman

My Feedback: (2)

Daffy Duck was pretty good.........I think the nose is more of a Platypus looking beak. "Air Platypus" is the name I choose.....what do you think?

a088008

I like the name. I just hope the plane does not take it literally and try to swim in the air. It will look like a fish on land. Maybe I can come up with a new aerobatics pattern - "the platypus". LOL.

-Q.

imsofaman

My Feedback: (2)

All joking aside, your design is awesome! Looks like you have a winner. Post your results please.

a088008

Thanks for the support. I like the design, and the covered plane looks awsome. I used monocote and it's made the whole structure very rigid and strong. I'm very pleased with the result as I was worried about wing warp.

I've covered and stretched the film, but I need to redo a couple of spots due to a !#$%? heat gun. It has uneaven heat distribution (I was not aware of it until I looked - nearly burn my eyebrows in the process - just joking ) which caused certain spots of the film to overheat and burn a hole in one particular case. It's not long now and I'll be doing some glide tests, but before I do I'll post some pictures of the final, covered model. Look again tonight, or tomorrow for some pics.

-Q.

Speedo125

Great design, very nice photo's. I'm thinking that a EDF version would be really special. Please keep us posted. You DID save the plans/patterns when you built her, right??

a088008

Well. I can give you an update. I did some glide tests today without any gear in. It was VERY pitch sensative. I did have the CG a little back and this made things quite interesting. The plane was gliding well and then all of a sudden pitched up at a 30 degree angle and then 45 degrees down. This all happened in about 0.2 seconds. Yip, lightning fast. I could not believe it. A tiny gust of wind had taken the nose up and then pushed it down. The nose just amplified the reaction. I'm going to be putting a lot more weight up front to help control this, but I'm afraid that the plane might be too unstable to fly. I'm still going to try, though.

I have thought about an EDF version. The plane actually has an air intake under the back of the wing. Look at the pictures closely and you'll see it.

Anyway, I'm going to finish the covering tonight and post some pictures.

There has been such an overwhelming response to the design that I'm determined to make her fly. I'm going to make modifications, in the event the current one is unflyable. The second one will definately fly! And, yes, I've got full 3D plans of the ship.

-Q.

William Robison

My Feedback: (3)

a088008:

Nose weight and about 1/8" reflex in the elevons. Changed a C/L flying wing from unflyable into fantastic.

Throw all but the wing into the can,
. If you can fly that, you're a hell of a man.

Bill.

a088008

Thanks for the advice on setup William. I'm intending doing just that, although I'm not sure what flyable is going to mean for his plane. I'm basically going to punch the throttle and hold on for as long as I can. Kind of like riding a bull. I do not pretend to be an expert pilot, but I'm prepared for this plane. I have been having day dreams about flying it for about 2 months now. That, and the fact that I'm going to set the controls very conseratively to begin with. This will make sure that my minor mistakes don't become big ones, although I suspect that this plane will not tolerate even a single mistake.

-Q.

William Robison

My Feedback: (3)

Q:

Find the aerodynamic center, set the C/G a little ahead. Suggest 1/4". That will instantly make the airplane stable. Consider an arrow.

Initial trim on the elevons should be a little up (Reflex).

If you set the C/G too far forward the airplane will be too fast, but with sufficient reflex it will fly. Move the C/G back a little at a time, and you'll reach a point where the speed is good, the glide is good, and it wont be overly sensitive. Unless you set the surfaces to "3D" travel angles.

A flying wing is quick.
. Keeping it level, there's the trick.

Bill.

a088008

Thanks for the advice. I'm definately going to set the balance point a little before the CG. I'm going to start at 10% (the guys in the aerodynamics forum have been a great help in determining this). I'm going to also add reflex, as you suggest.

You've given me hope. I'm quite excited to get it in the air now.

-Q.

a088008

The next 7 posts are the lastest pictures of the plane. I've covered everything and got the control surfaces in place. The last step is to setup the radio gear and CG. Then, it's time to down a glass of the "right stuff" and head on over to the runway.

I hope to have a flight report in a few days.

-Q.

a088008

picture 18.

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picture 19.

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picture 20.

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picture 21.

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picture 22.

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picture 23.