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Old Aug 07, 2007, 04:22 PM
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Ace, I came close to getting the newest Stryker but backed out because it is too fast for it's size but it should not bother a young quick thinker. John235, the DOWN thrust added to G1 was an attempt to kill some lift on the main wing and assist going through the inside loop at vertical. Yesterday while flying the Ga. Goose, I noticed a fast climb with the new motor and some squirming at the rear. It was found to be tail heavy and after moving it's 4AH battery forward about 1", it became rock solid again and with a couple of elevator UP trim clicks, it made a slow smooth landing. the re-balance put it at 10% static margin for a fast nose down approach when no UP trim is added. Charles
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Last edited by canard addict; Aug 08, 2007 at 08:13 AM. Reason: Clarification
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Old Aug 07, 2007, 09:20 PM
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Charles, I've done four brushless Strykers in the past with a 2815-200kv and a few edf ones. They hit about 80 mph with either set-up,but this is my first as a canard.
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Old Aug 08, 2007, 02:42 AM
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Charles, Thanks for the explaination about thrust lines. I think I can see the issue is more related to what happens in the vertical orientation during a loop rather than in level flight. The propellor on your Egret diagram looks a bit small though... Did you have any issues with prop clearance?
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Old Aug 08, 2007, 08:09 AM
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John235, The Egret prop is an APC 7-5 on the Medusa 28-32-1500 and is 3" above ground which puts it at wing bottom. It has not been a problem at our grass field. The winglets are below the wing too much and have scraped a few paved runways but this can be corrected easily because they just screw on the hard wood wing tip ribs. On the subject of Mickey Duck flying straight and level: since the thrust line is at the highest point except the winglets,all other drags are below it which tends to give a nose down rotation of resultant forces. But this is counteracted by the lift of the canard which holds the nose up. When the speed drops,the canard drops the nose to cause more speed for stability. I love to hold full UP elevator and reduce throttle and observe the nose up-down oscillation while the main wing holds the rear of the model in stable flight. I noticed that Rutan's ships have the thrust lines and wings pretty well lined up near the same plane. Charles
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Old Aug 08, 2007, 09:35 AM
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EDF Discussion

tIANcI, Your input to the EDF subject is appreciated. You, John235 and Mustang Ace seem to be better candidates for using them at present. If I were to get one, It would have to be mounted inside the fuselage at the rear and would need to operate at no more than 25 amps probably with a 4S2P for the purpose of saving amperage. Would internal mounting be a problem and also if we had a large opening in the nose,how would the rush of air do in one of my square cross sectional fuselages with battery, switch and ESC mounted inside? I picture a glider such as the Gentle Lady made into a canard with a Canardly type rudder mounted on a hardwood flat piece extending from the fuselage top. It would be for sport flying since it probably could not climb at a fast rate. Charles
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Old Aug 08, 2007, 01:41 PM
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new project and experiment that worked well

This is my latest EDF canard project based on the Stryker fuse since it has worked great in the past. Canards and elevons will be coupled and all surfaces are balsa sanded round at the le and te for better aerodynamics.Same fan as the v diamond canard and hurricane 9 gr 24 ounce servos all around.

Also,after seeing HL's Soarjet edf sailplane I decided to try it with a Ripmax Coyote I never had to much luck with as a motor glider,so I glued a GWS edf-64 with Razor 2500 inrunner and a Wattage Impeller to the wing and used a TB 18 esc.It only pulls 15 amps and 155 watts but climbs better and faster than both the speed 400 and mega 16/15/4 previously installed and still maintains great energy out of a dive,I'm very happy with it.
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Last edited by MustangAce17; Aug 08, 2007 at 01:47 PM. Reason: grammar
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Old Aug 09, 2007, 01:38 AM
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Quote:
Originally Posted by canard addict
Would internal mounting be a problem and also if we had a large opening in the nose,how would the rush of air do in one of my square cross sectional fuselages with battery, switch and ESC mounted inside?
What I have read is that the inlet area should ideally be around 90% of the x-section area at the fan. The same source also suggest the exit point should also be around 90% of the x-section area at the fan except fast models can apparently benefit from smaller exit area such as 80 - 90%. I also read that clean flow around the inlet area and ducts is needed for good efficiency, since too much turbulence will affect the fan performance and can produce more noise, similar to what can happen with pusher props. Again, I don't have first hand experience, so hopefully others can contribute their experiences.

Quote:
Originally Posted by canard addict
I picture a glider such as the Gentle Lady made into a canard with a Canardly type rudder mounted on a hardwood flat piece extending from the fuselage top. It would be for sport flying since it probably could not climb at a fast rate. Charles
To be honest, I'd keep the EDF for faster models, since I think for a glider you'd get more useful thrust and better efficiency with one or two motors stuck on pods. Twins motors and folding props on wing mounted nacelles is another possibility. Its just a pity that twin brushless motors will need two ESCs.
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Old Aug 09, 2007, 07:32 AM
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Ducting for EDF's is calculated from FSA ( Fan Sweep Area ). This is the area of the inside of the fan shroud, minus the area of the fan hub/motor. Intake area should be 110-120% of FSA tapering smoothly to the front of the fan. Exit area should be 80-100% of the FSA. A larger exit will give better static thrust ( easier hand launch ) and a smaller exit will give more velocity ( better top speed ) As with anything else it is all a compromise for the characteristics you are looking for in any given design.

John
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Old Aug 09, 2007, 10:04 PM
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John,speaking of edf's it would be a great idea to add a canard to one of your f-15's to see how it would affect manuverability, I remember a NASA experiment like this and would love to give it a shot when I have the $ again.Also, guys I was wondering a train shop today since I heard they had plastic and diecast planes and found a XB-70 Valkyrie model and picked it up and built it just to see how it looks. It has great lines and would be a fun profile to try and not extremely difficult as a full fuse.
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Old Aug 10, 2007, 08:34 PM
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Delta Finishing Touches

The Double Delta aka D squared is finally finished and ready to fly. The delay at present is the high temperature and air polution in Atlanta. A new ESC put a stop to the glitching. Some white was added to the fat part of the fuselage and some Hobby Lobby tape was added on the wing bottoms to cover the Vees at the control hinges. All of your inputs on EDF's has been very helpful. Any knowledge or experience on tha Alfa from Hobby Lobby with 4S and Mega power? It seems to have more power for it's size so far. They say to remove 3 of the 6 blades for brushless. The fuselage would need to be large for the fan to be inside. I would want a smooth internal tunnel with the battery etc mounted in an inclosed section above. Charles
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Old Aug 10, 2007, 08:56 PM
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D2 looks great Charles. I'm working on my stryker tonight since I got the parts needed, so possible maiden tomorrow.
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Old Aug 10, 2007, 09:20 PM
Dr John
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Charles,

Looking good.

I would be leary of cutting the blades off unless you have a spare. I tried that once on my Wattage/Astro fan and the plane would hardly fly.I would only cut them if it was absolutly required to keep the amps within limits.

Kyle,

I may well do a canard jet but will start with something that normally uses canards.

John
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Old Aug 10, 2007, 09:40 PM
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ok John, sounds good. A eurofighter is right up my alley!
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Old Aug 11, 2007, 02:31 AM
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Charles, is it the 60/25 Alfa fan that you are looking at?
Where did you read about removing the blades?
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Old Aug 11, 2007, 12:38 PM
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Alfa EDF Hobby Lobby

John235 the info is here:http://www.hobby-lobby.com/ductfan.htm What do you think? Is there any thing good with smaller diameter? It is ALF5103M Charles
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