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Old Jan 12, 2010, 02:15 PM
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You guys are right that activity is brisk here. Several questions are unanswered which may require timely consideration. Please speak up if you can help. Because of interest in three surface design and since they have a front or "canard wing", I feel that it is OK to discuss them here. Where else would you go?? The night I tested my 3 winger with slow tosses in the house, it was cold and breezy outside. The next day with brisk tosses outdoors, the model had tail heavy oscillations. I cut 1/2" from each canard tip and tapered the LE back to the original tip chord. I added nose weight for a smooth nose down glide. Doing this caused the CG to move forward nearly 1 inch for the glider or 3 inches scale. To return the CG back to where it was or to where I believe it should be, The canard area will have to be reduced more or the wing areas to the rear increased. The question now is what happens to the CG with high lift airfoils which may shift the balance compared to the flat depron?

Nickchud
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Meanwhile, I needed a quick fix of progress, so I built the Stuntcat. Just a Sunday afternoon and 3 sheets of Depron (6mm x 500 x 700). that's 1/4" x 20" x 28", I think. Also a bit of tape and some plywood scraps. She's just crying out for a canard, don't you think? I built the fins bigger in anticipation of converting it.


A raised canard, back from the nose to protect it on landings, would move the CG forward and give super looping and turning performance with the help of the elevons IMO.


Conehead
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Charles, that 3 wing/ surface glider looks great. Bet that will be a fun build.


The excitement and fun is happening but action is hard to come by. I need some of the drive form Nick, Steve and others.


Cybernaught
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What power train do you plan for it? 2.5 lbs is heavier than anything I've ever build. What's the planned power system?

BTW, and this was not planned, the Whisper needs more thinking and DD has lost my interest a bit, and I had this old Zag type wing that I'd started some time ago... Anyway I want a big camera plane so I started to play with the wing and it's morphing on me. Something weird is happening to the front. See Pic. I was going to call it APE for Aerial Photography Experimental but now I'm thinking "WalulaTu".


It needs a small efficient 2 to 2.5 ounce motor preferably an in-runner capable of 250 watts on an 8" prop. The battery will be well forward if the design stands as is. Your WalulaTu or APE with it's four sq. ft. wing will dominate flight, as I see it, but it will also put the CG back far enough to have a good front end canard control combined with the elevons. It should make an excellent carrier for your camera.
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Old Jan 12, 2010, 02:51 PM
What could possibly go wrong?
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Charles!

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The question now is what happens to the CG with high lift airfoils which may shift the balance compared to the flat depron?
It was you who said to me: "just point it into the wind and give it a push." Great advice, I've never looked back.

With my Stuntcat I was following a plan very close to Steve's. ie For a camera ship, take a flying wing and add a canard for extra control / stabilty. That worked very well last August with my Minislinger, but it was only big enough for a Flycam type of camera. My digital with a servo weighs about 150gms (5 or 6 oz, I think).

I like your suggestion of mounting the canard high to protect it from rough landings. First I'll try and fly it as is. She's all painted up and ready for action now. Thursday might be a good day.

Steve! I tried EDF once, but I didn't have much joy - not very good power to weight and they like to fly fast, faster than my preference. I stand ready to be corrected, but on that attempt I lost interest.

cheers

Nick
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Old Jan 12, 2010, 04:10 PM
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A Pleasant Surprise

My three surface model of 3mm depron is so light that I added too much clay to the nose without realizing it. The forward CG had me discouraged. When trying to remove a small piece of clay without breaking the nose, a large piece of it came off. The glider now sits on the air and goes much further without oscillation. The CG moved rearward about 2.5 inches for the full sized model. The data has been corrected on my previous post. The balancing was tricky as compared to the same for a sheet balsa glider. Plans can now be drawn with enthusiasm for the larger version.
Charles
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Old Jan 12, 2010, 04:33 PM
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New XB-70 is in the works. This one is 24" vs my 20" version. Plus it will have 500+ watts vs the previous 50ish watts. True XB-70 fans might be a little perturbed because I've modified it some to make it a little more speedy... hopefully. No drooping wingtips and pitch will be canard only for all you purists.
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Old Jan 12, 2010, 05:39 PM
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DreamArcher Mike, That is my kind of model, a canard delta. You could start a trend with that one! I remember The full scale one was fast at mach 3. Could it hold the world record? Where did you get the dimensions? It looks like it will be very stable and not sensitive to CG variations. A video would be awesome! Post 2720, page 182 shows picture and interesting text. The scale version had rear elevons per text.
Charles
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Old Jan 12, 2010, 07:26 PM
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This is the maiden of my first one. Actually it's two flights but the beginning is the maiden. It's elevator only with fixed canard. A bit pitchy at low speed or maybe I'm just not used to flying a delta. Good at high speed.

For the new one I was thinking elevator and canard for slow speed, and then canard or elevator only for high speed. I'll experiment with the setup.

Thanks for the info on how the real one works. I was looking for that a while ago and couldn't find it. I just took the 3-views and a calculator. 3-views

20" XB-70
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Old Jan 12, 2010, 08:38 PM
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DreamArcher
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This is the maiden of my first one. Actually it's two flights but the beginning is the maiden. It's elevator only with fixed canard. A bit pitchy at low speed or maybe I'm just not used to flying a delta. Good at high speed.

Thanks for showing,Mike! That model would look threatening with an eight foot length. Could The pitchy condition be corrected with a little more lift up front by adding more area and/or more incidence to the canard? A tail heavy condition can also cause vertical instability as I see it. My preference regarding controls would be elevons rear and elevator up front if it could be arranged? I would buy the XB-70 if it appeared on the market as an electric. I believe that modelers are begging for something unusual.
Charles
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Old Jan 12, 2010, 09:48 PM
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An eight foot length would be nice. Who knows maybe it will happen. I wanted to develop and evolve my RA-5C Vigilante but it looks like it might be the XB-70 instead so it might happen. Of course a bigger one would have to be more to scale. I wouldn't cheat on the engine ducting like this one.

I'll probably try a slightly more forward CG first. Although it didn't have the problem at high speed so maybe it's not that big of a deal to put up with at low speed.

There's at least one XB-70 on the market now, but I didn't like it. Just looked cheap.
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Old Jan 13, 2010, 01:02 AM
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Tonight's progress. Got more done than I expected and it came out straighter than my planes normally do. Probably because I was just slapping things together. I need to do a little more shaping around the canopy since it looks a little boxy.

I don't want to invest too much on a plane with 500+ watts since it might crash so I'd like to get done with it in 3 nights and then 1 more night to paint (white).
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Old Jan 13, 2010, 04:09 AM
Onward through the fog.
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Originally Posted by DreamArcher View Post
Tonight's progress. Got more done than I expected and it came out straighter than my planes normally do. Probably because I was just slapping things together. I need to do a little more shaping around the canopy since it looks a little boxy.

I don't want to invest too much on a plane with 500+ watts since it might crash so I'd like to get done with it in 3 nights and then 1 more night to paint (white).
Looks good Mike,

I liked the Video of your original XB-70, so muich, that I downloaded it for future reference. My original Walula had elevons with a full flying canard. the Canard was mixed with the elevator function and it was pretty maneuverable. I believe you said the new one will have the canard frontal elevator for pitch and ailerons for roll??? I'm curious to see how it works out for you. Looking at the vid and the high alpha slow flight I think the nose could have been lower if the canard had been operational but you probably know a lot more about canards than I do since i"m new to them.

Only had a couple of hours to work on WalulaTu (WalulaTula??), today, but I'm slowly making progress. Fuse shape and camera mount are the main problem at the moment. I was a door-handle repairman today after all the running around getting parts. I hate it when "Home Maintainance" gets in the way of the important stuff.

I'll post pics when I see what direction this silly thing ends up going in. It has a mind of it's own, like most of my builds. I'll video the maiden too. Good or bad, I'll show the results. ...

Some good posts lately. Very interesting what you are all up to. Keep it up, and Keep at it! This thread is becoming my number one read...

Steve.

"Scratch-buildin' Foamies is like a box o' chocolates. Ya never know what yer gonna git."





Edit: Jan 13, 2010 7:30pm.
It's dark thirty and Im ready for a bit of R 'n R along with a hot chocolate. I can finish up tomorrow while Edna's marketing in town. Maybe get in a maiden too if the gale force winds don't return. 4 Pics below.
The plywood sheet on the table is 30" deep and 48" wide for a size reference.



Edit: Dec 14 2010 7:42am
CG is very rearward. Canopy moved to rear of plane as a cover. The green nose didn't look good so... See last 2 pics.
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Old Jan 13, 2010, 10:30 AM
What could possibly go wrong?
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500+ watts Mike! Jeez!

Steve!
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Some good posts lately. Very interesting what you are all up to. Keep it up, and Keep at it! This thread is becoming my number one read...
Right on!

Nick
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Old Jan 13, 2010, 11:00 AM
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Mike and Steve, Thanks for showing. It is fun to follow your projects and I look forward to learning from them. My 3 surface design is about to be drawn up. It may be built by Spring.
Charles
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Old Jan 13, 2010, 11:04 AM
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Yeah 500+ watts is my concern. That's why I don't want to spend more than 3 nights building this. I'm also entering it in Don's new flat foamy speed challenge is why so much power.

On the control surfaces another option is elevons and the canard on the flap channel. If it flies as well as the previous version I should be able to experiment with several different configurations.

I just found this EDF XB-70.
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Old Jan 13, 2010, 05:06 PM
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Mike, the videos were great. After watching the first one, there was a giant one on the same strip.
Charles
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Old Jan 14, 2010, 01:06 AM
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Didn't have much time tonight so I only built the canard. It turns out it's only a little over 6 in span, 13.75 sq in and the moving part is 1/3 of that. It's quite small. I don't know what to think about this.
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