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Old Aug 23, 2007, 01:24 AM
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Charles, Now I understand the oscillation issue. It seems very similar to what you wrote about the main wing lifting first, then bouncing on the nose wheel with one of your previous designs. Now we agree that my design's canard has approximately 20% area of the main wing, I double checked and found its 21.7%. Based on my metric measurements I posted previously it comes to 43.4sq" canard area and 199.8sq" wing area. When finalising my drawings the canard area increased to 45.9sq" which is 23%. Full details are shown in the attachement. When compard to the Shinden from Hobby lobby, although the relative areas are very similar, the canard in my design has a larger span and higher aspect ratio.

PJW, Thanks for your comments about the fin area. You may well be correct about the lack of fin area. I am seriously thinking to increase the tail length. Even just 0.4" would be an improvement to give more fin area and longer moment arm. I have thought about winglets, but decided I could add them later if testing shows any problems. There are a couple of reasons I decided to use a single fin instead of winlets. Firstly, the fin can be placed in a more rearward position which gives a longer moment arm. Secondly, in the event of a 'landing mishap', winglets tend to get smashed up and can cause further damage to the wing. I built one canard previously that suffered this problem. Finally, I am a bit wary about how winglets affect the efficiency of the wing, but I will add them if they are necessary.

It occurred to me, that a possible disadvantage of using a fin, is that it may less effective when the wing is operating at high AOA if there is turbulence above the fuselage and wing. I don't think that winglets would suffer this problem to the same degree.
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Old Aug 23, 2007, 07:33 AM
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Congratulations, ACE!! That was a big accomplishment with the fan and a small fragile model. It must feel great and you learned what works. Some day you could scale one up from there and there are lots of variations to try. Charles
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Old Aug 23, 2007, 08:12 AM
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Mr Ace, its great to hear of your success. Do you have any ideas about what design aspect has made the difference between the firebat and this design?

I also wanted to ask what the AUW of your model is, and the wing area if possible too please.
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Old Aug 23, 2007, 08:21 AM
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Way to go Ace. My small LEZ would snap out of a loop at the top until I mixed elevator (canard) to flap. The ailerons were using two servos programed as flaperons.

John
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Old Aug 23, 2007, 11:01 AM
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Yaw Stability

John235, I have been looking at some different models with passive winglets or with fins on the fuselage and have been surprised how close to the CG they are. Check post # 117 for the FW 42. The heavy motors are in the CG area and the fin is up close to the wing. The pilot says it flys beautifully.Also there is a Wing jet by www.airborne-models.com which has a big ducted fan sitting at the wing's TE with stabilizing winglets practically siting on the CG.Since the winglets, like your fin does not have to control the turns, they must be OK as long as they are not in front of the CG IMHO. BTW, The Voyager 55" Long EZ clone has 26% canard area and not a lot of incidence. The model flys very well on the beautiful delta combination wing. I believe that if your model is well balanced and has good speed, it will be a winner. I can see that you have put a lot of thought into it and look forward to following it all the way. BTW, on the Shinden, the center of the winglets are 9" behind the CG. Charles
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Old Aug 23, 2007, 12:03 PM
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Wing-tip vertical stabilizers have a side-effect bennefit. They act as tip-plates or "winglets" reducing tip vortices and thus reducing drag AND increasing the wing's lift.

There are too many reasons in favor of the wingtip vertical stabilizers on a Canard for me to consider any other way to go.
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Old Aug 23, 2007, 02:03 PM
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Thanks for the input,huber. We are seeing more of those stabilizers on conventional models and I presume they help with the knife edge. Maybe the canards taught them something. Charles
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Old Aug 23, 2007, 02:43 PM
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Thanks for the compliments guys, I was pretty excited myself. Once I fix it again I'll try to get a video of an entire flight. John235- as far as I remember the wing area is 93 sq. in, AUW is around 20 ounces and 290 watts of power , I'm not quite sure what differences from the Firebat may have helped other than a almost flat airfoil with both le and te sanded round.Pmpjohn,thanks for the tip, I can do that since I have two servos and might give it a shot after I fly it once more although I have to change out the rx. Charles, I believe the SFG's or Side Force Generator tech. may have very well come from canards I have flown them on a Mini Funtana X and can say they do help knife edge flight by adding additional lift at lower speeds,like huber mentioned, from what I remember rudder input needed was half of what it takes without them.Although later on I took them off since they lowered the roll rate and I'm a 3d pilot at heart with those type of planes. BTW, I think I might throw something like this together today
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Old Aug 23, 2007, 02:45 PM
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Virginia
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There are lots of great models in this thread. I wish I had found it sooner. I've been building a Richmodels EP Quickie that I picked up from AKModels. Very interesting plane and it's my first plane with a canard. The maiden should be this weekend. I posted a build thread over here:

http://www.rcgroups.com/forums/showthread.php?t=716004
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Old Aug 23, 2007, 02:48 PM
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hey Lost good to see you here,I'm only responsible for three of the models here but it's a great thread to learn and share. I saw that quickie fly a few months ago and it did great,I thought about getting one but I'm having a blast building my own canards and so far two of the three have flown.
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Old Aug 23, 2007, 04:09 PM
89" Kool Aid drinker.
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United States, CA, Ventura
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Ace: That pic sure looks familiar. Good to see it getting some use. That really is an interesting plane. Twin turbo prop pusher with the high mounted canard. I would like to see it in the air, but it doesn't look like its wheels have left the pavement in a while.

I have the RCM plans for a 56" Quickie that I keep thinking of building. I have had the wings and fin quoted for foam, just haven't gotten the will to order them. One day I will though.

Mike
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Old Aug 23, 2007, 04:16 PM
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Mike thanks for posting it, I've started on my design that is pretty close,two brushed pusher motors and high mounted canard
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Old Aug 23, 2007, 04:28 PM
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Can't wait to see it done.

Mike
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Old Aug 23, 2007, 04:41 PM
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well it won't be anywhere near as nice but will be a fairly quick project,and I'm trying a canard with elevons as the only controls
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Old Aug 23, 2007, 09:56 PM
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the whole family thus far

including my newest project, still have to finish F-16,Stryker and the new one and try to fly the XLiner again and fix the F-88's lg for another test flight
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