RE: Red Duck  
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All Forums >> RC Airplanes >> "1/2 A" & "1/8 A" airplanes >> RE: Red Duck
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RE: Red Duck - 4/23/2008 5:13:06 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		Remby... I didn't mean to give you a 'yuck'. Just now I went back to the first post, again, and from what I see in the enlarged picture, the 'orange' color of the front wing looks like the elevator, and the 'red' is the canard solid portion attached to the fuse. So the elevator [moving] portion looks like maybe 1/2" by 20" [less the width of the fuse]. My RC canard front wing is 12" by 4" total, and covers a 2" wide fuse. The stationary area is 12" by 2" with 2" by 2" glued to the fuse, and a piece 2" by 2" between the elevators glued to the fuse. That leaves Two elevators each 5" by 2", one each side of the fuse, both of which move up and down 35 degrees. So my canard plane has 10 + 10 = 20 square inches of moving elevator.
If your fuse is 2" wide, then your elevator area is 9" by 1/2" plus 9" by 1/2", or about 9 square inches total. That's less than half the area of the elevator on my plane, built as per the kit. Perhaps I'm looking at your picture incorrectly, as I can not see a 'hinge line' on the canard. My previous post was an intent to say, "Looks like you need more control surface in the front." One of your posts did say that the plane dropped its nose and went down...... perhaps more "UP' elevator surface could correct that.

(in reply to Remby)
       Post #: 26

RE: Red Duck - 4/25/2008 6:01:39 AM   
Remby


 

Posts: 589
Joined: 11/2/2002
From: Russell, PA, USA
Status: offline 		Yuu
I can add a bit to the elevator part that moves fairly easy.I built it as the downsize showed, and the plans described the responce as plenty, so I followed the plans. Some more up attack angle on the horz. Stab can be done as well, but not as easy.

I am also going with more down thrust, as well as keeping the C.G. right at the minimum point. Will post as to how this goes.

Thanks for the suggestions all.

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       Post #: 27

RE: Red Duck - 4/25/2008 3:47:05 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		Remby... I don't trust that down-thrust business, but go ahead and try it. I can think it through the up angle on foreplane lifts the nose, and the down-thrust on the rear engine pushes the rear 'down' while trying to lift the front...a forced rotation around the CG.... I guess that could work.
Another thing I found was that the canard plane needs speed to stay aloft if it stalls, the canard stalls first and the nose will drop, and will not come up until you get enough air speed again. Gaining air speed after running out of fuel can be difficult, so watch out for the stall when landing, and land 'hot'. How fast is your take-off speed? Fast enough to get past the stall?

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       Post #: 28

RE: Red Duck - 4/25/2008 5:47:43 PM   
Mr Cox



Posts: 282
Joined: 7/20/2007
From: Gothenburg, SWEDEN
Status: offline 		Interesting balancing act...
I'm a bit lost in the numbers, seems like it has gone from about -2 degrees downthrust to -4 degrees downthrust? i.e. more and more upthrust?
This would make sense if the engine was above and in front of the wing, thus counter balancing a momentum of the wing drag.
With the engine behind the wing (and behind CG) you might instead actually need downthrust in order to push the rear down in a rotation around the centre of lift...?

Getting it to balance at the CG with the engine running (but plane stationary) could then actually be a good test, the front stabiliser would then also be neutral in flight (which is a good thing) and the glide with and without engine more equal...

(Please note that I have never flown anything like this myself, I'm just intrigued/interested in the balancing problem)

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       Post #: 29

RE: Red Duck - 4/26/2008 3:16:01 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		Remby, how about posting another picture [side view] showing the connection of the canard to the fuse. You know what it looks like, but we don't. Looking Again at the picture in post #1, it May be that the canard is mounted 1/2" above the fuse on a short pylon, and the full canard rotates on a brass tube or something on the front of it, like several old combat planes with "stabulators"? I still do not see any hinge lines on the foreplane.
Another question: when you write "-4 degrees down thrust", does that " - " sign reverse 'down' into 'up'? I read '-4 downthrust' as different from '4 degrees downthrust'.
This sure is an interesting thread for me. Keep at it, please.

edit: correct spelling of lilnes...

< Message edited by Yuu -- 4/26/2008 3:17:22 PM >

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       Post #: 30

RE: Red Duck - 4/26/2008 4:59:12 PM   
Remby


 

Posts: 589
Joined: 11/2/2002
From: Russell, PA, USA
Status: offline 		O.K. Ill post the data later tonight, Yuu the "yellow" forward elevator part is the moving part, around 3/4" wide.

Will post some more later tnight.

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       Post #: 31

RE: Red Duck - 4/27/2008 6:56:13 AM   
Remby


 

Posts: 589
Joined: 11/2/2002
From: Russell, PA, USA
Status: offline 		Yuu
Another picture will be a bit of a delay, I need to fit the forward section before I can photo it. Also, my digital camera is so old is is a 100 pixel, getting a quality picture from it is a effort, to say the least.

I will keep at it, I do think it should fly and will extend the elevator to give it more air deflection, as well as more engine -down thrust. If these can be balanced I should be able to get it in the air.

Mr_Cox

You have the idea, and the trouble is interesting. I find carnads have a cool look, and want to see it in the air. The body damage is going to be fairly easy to repair, but must be kept light or it will be even more "bricky". If all turns out O.K., I can build another body as the first only took about a week to complete.

More soon..

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RE: Red Duck - 4/29/2008 2:57:57 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		I'm looking at the picture in post #1, and it looks like a flat bottom air foil mounted flat on top of a flat fuse. So, drawing a line through the TE of the wing forward to the nose of the LE.... looks like there is some 'incidince' built in... so the wing 'incidince' is lifting the tail up... and so, the nose goes down? Maybe a popcicle stick under the TE can solve that, for a quick check. I did a 'hand crank' of the CG and I get 1.33" in front of the wing LE, which is close to the Center of the CG range you posted. Keep at it.
edit: spelling again..

< Message edited by Yuu -- 4/29/2008 3:00:29 PM >

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RE: Red Duck - 4/30/2008 4:57:59 AM   
Remby


 

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Joined: 11/2/2002
From: Russell, PA, USA
Status: offline 		Yuu
Thanks for your post. So, the computer is giving me good numbers then. I checked it using a known carnad data, and it was perfect. You giving the 1.33" means a confirm as to the C.G. as far as the basic layout.

The lifting of the wing's T.E. is another thing I have not considered, I've only reworked the layout keeping everything straight, that is somthing I can look into.

I will get a mesurement of the Elevator's positive angle, where it is zero on the fuse, that will add a bit of info as well. Thanks for the idea!

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RE: Red Duck - 4/30/2008 4:00:30 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		Remby, I found the 'incidence' info I was looking for. It's in the 'Scratch Build' etc section, and thread "Finding chord line of wing", post #5. The picture #4 of post #5 is what I was looking for. I was having trouble with this last summer. I had increasaed the incidence of the wing for when I was trying to fly Texaco and wanted more lift and fly slower. Then I put on a better engine to fly faster and more aerobatic, and had all sorts of problems with inverted flight and loops, etc. Finally the light came on and I removed the extra incidence, and it flew okay again. I was especially interested in the 'undercambered' wing and how the incidence would affect flight. Take a look at post #5 over there.

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RE: Red Duck - 5/14/2008 4:55:14 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		Remby....I just spent an hour looking for that drawing... it must keep moving around, or my eyes have gone bad again. You can find it easily by doing a 'search' for 6961521 and scrool down to post #5 which has four drawings. You will see the 'chord line' and see, if the flat bottom wing is mounted flat on the fuse, the 'chord line' will by "UP", raising the rear of the plane [since it is a canard with the big wing in the back]. This will automatically cause the nose to drop, since the plane will rotate about the CG. I hope this will solve your problem, with a little shim under the TE of the big wing. I hope you can get it to fly, as canards look neat inthe air. There is a real 'Easy' that flies over my house occasionally on the way to the airport here. If I knew how to post here, I would take the pic off the desktop and insert them....

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RE: Red Duck - 5/15/2008 4:51:18 AM   
Remby


 

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Joined: 11/2/2002
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Status: offline 		Yuu;
Thanks for the data. I think you may have somthing here, I never considered doing the wing angle change to get it to keep its nose up. It was not suggested in the article for the Lazy Duck. So around 1/16" or so on the T.E. of the wing up, is that right?

It looks like it may be a answer. The Duck is just " stewing" for now, am finishing up another carnad and also working on that Lil Esquire rebuild, and these are getting finished now, so will give the repairs and things the Duck needs a going over soon.

The drawings do help a lot, I wish more info on carnads were easy to find, and easyer to understand, and they are really cool. Makes getting them to fly somthing to really feel good about.

I will let em' know here when that happens.

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RE: Red Duck - 5/18/2008 6:16:14 PM   
Yuu


 

Posts: 303
Joined: 9/4/2006
From: Shawano, WI, USA
Status: offline 		The "Red Duck" is ... "STEWING" ??? ROFL !! Yes, a picture of incidence is worth a thousand words. Thanks to the guy who posted it. I think a 1/16" under the TE of the big wing may not be enough. I had to use two popscicle sticks last summer just to notice a difference. After I got it sorted out, I added to the height of the original fuse with balsa and put some covering 'trim' over the repair. It does fly a lot better now. Good Luck, Remby... and keep the photos coming!

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RE: Red Duck - 5/18/2008 8:57:17 PM   
buzzard bait


 

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From: Ithaca, NY, USA
Status: offline 		Remby, have you done a test glide? I would want to know how that comes out before adding power and adjusting the thrust line or incidence.

Jim

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RE: Red Duck - 5/19/2008 5:09:12 AM