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Old Jul 14, 2012, 12:22 PM
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Elios000
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has any one tried a V-tail canard well i guess V nose? or would that not work
Welcome Elios, The V nose may work and we need advice from someone who knows for sure. I had a model with a rectangular canard wing and my regular swept back main wing which both had dihedral. It wobbled or squirmed in bumpy air whereas the next similar model with flat wings, the Georgia Goose, was stable. The Egret had a rudder up front which was small but effective. The V nose would have both vertical and horizontal forces to deal with and the horizontal area would have to be used with the canard CG calculator.You have a great suggestion,Elios, which requires a bit of searching to see if it has been tried.

Charles
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Old Jul 14, 2012, 03:23 PM
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Neenah, WI
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Originally Posted by Elios000 View Post
has any one tried a V-tail canard well i guess V nose? or would that not work
Putting V-dihedral in the canard was fairly common for free-flight canard designs (~10 degrees on each side). The canard-dihedral helped keep the nose up during the circling turns.
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Old Jul 14, 2012, 07:34 PM
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Originally Posted by canard addict View Post
Elios000


Welcome Elios, The V nose may work and we need advice from someone who knows for sure. I had a model with a rectangular canard wing and my regular swept back main wing which both had dihedral. It wobbled or squirmed in bumpy air whereas the next similar model with flat wings, the Georgia Goose, was stable. The Egret had a rudder up front which was small but effective. The V nose would have both vertical and horizontal forces to deal with and the horizontal area would have to be used with the canard CG calculator.You have a great suggestion,Elios, which requires a bit of searching to see if it has been tried.

Charles
Love both G Goose and Egret, beautifully done. Wish I had the experience starting with balsa model first, instead of sculpting foam only.

Just curious, what will be like if the upward rudder in Egret is replaced by a rudder downward, like attached to the steerable nose leg. Definitely will give the pilot an unobstructed view?
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Old Jul 14, 2012, 09:47 PM
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This one has a v-tail!

(Sorry, couldn't resist!)

(See post #8 for more info)

http://www.rcgroups.com/forums/showp...45&postcount=8
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Old Jul 14, 2012, 11:13 PM
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Originally Posted by canard addict View Post
Elios000


Welcome Elios, The V nose may work and we need advice from someone who knows for sure. I had a model with a rectangular canard wing and my regular swept back main wing which both had dihedral. It wobbled or squirmed in bumpy air whereas the next similar model with flat wings, the Georgia Goose, was stable. The Egret had a rudder up front which was small but effective. The V nose would have both vertical and horizontal forces to deal with and the horizontal area would have to be used with the canard CG calculator.You have a great suggestion,Elios, which requires a bit of searching to see if it has been tried.

Charles
ty
im A HUGE Burt Rutan fan
even made a bit of a pilgrimage last summer when i was in DC to see every one of his designs that was in the Air and Space Museum both at Dulles and downtown

VERY cool stuff if you havent been there you should go

any way yea i love stuff like V-tails and Canards so wondering if you could put them both on the same airframe and have it work
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Old Jul 15, 2012, 11:08 AM
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It can work, a little tricky. You will need additional fin area behind the C/G (possibly a LOT more) to make up for the destabilizing effect in yaw of the canard. Canard dihedral will be much lower than a conventional V-tail, enough to get adequate yaw authority, but absolutely no more than that, to minimize the yaw destabilizing effects. Aerodynamically it is not good, but it can be useful for other reasons, such as if you want to avoid putting control linkages in the wings.
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Old Jul 15, 2012, 07:01 PM
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Finally the flight video of my Shinden J7W1:
RC Shinden Canard WWII fighter (2 min 51 sec)


Consider the fairly low speed for its size as warbird and the inward location of aileron, Shinden's roll rate was pretty good, and stable at inverted flight. Definitely very manuverable, comparable to my GWS Zero (wing span only ~900mm vs. 1100mm Shinden). She stalled once and yet easily recovered under power.
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Old Jul 16, 2012, 05:07 AM
What could possibly go wrong?
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Looks fabulous Edwen. It's always satisfying to see your own brainchild working so well! Thank you for sharing.

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Old Jul 16, 2012, 11:30 AM
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Yes edwen! Your video should increase the pulse rate of any canard and/or Shinden lover.

edwen303
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Just curious, what will be like if the upward rudder in Egret is replaced by a rudder downward, like attached to the steerable nose leg. Definitely will give the pilot an unobstructed view?
There is lots of room below on the Egret's nose gear to add on a rudder.

Elios000
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im A HUGE Burt Rutan fan
even made a bit of a pilgrimage last summer when i was in DC to see every one of his designs that was in the Air and Space Museum both at Dulles and downtown

VERY cool stuff if you havent been there you should go
Me too, Elios! Here are two books you shoild like.

Don Stackhouse
Quote:
It can work, a little tricky. You will need additional fin area behind the C/G (possibly a LOT more) to make up for the destabilizing effect in yaw of the canard. Canard dihedral will be much lower than a conventional V-tail, enough to get adequate yaw authority, but absolutely no more than that, to minimize the yaw destabilizing effects. Aerodynamically it is not good, but it can be useful for other reasons, such as if you want to avoid putting control linkages in the wings.
On a conventional vee tail. if the left side is UP and the right side is DOWN, the rear end moves to the left for a right turn. If you reduce the vee to horizontal, the model rolls left. At what angle do you suppose the vee action turns to aileron action? Probably at less than 45 degrees.This has always baffled me. If the vee is moved up front for a canard with the left side UP, will it move to the left for a left turn as I suspect? What about the differential effect?

Charles
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Old Jul 16, 2012, 05:39 PM
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[QUOTE=canard addict;22178269]Yes edwen! Your video should increase the pulse rate of any canard and/or Shinden lover.

edwen303


There is lots of room below on the Egret's nose gear to add on a rudder.

Thanks Charles! To me this is the best complimenet from a CANARD pro, or a PRO-Canard modeller

If I have more time and spare parts, I might start working on J7W2, Shinden-Kai, the jet version of Shinden, with 70mm EDF.

For adding vertical stab, I have a feeling that an upward setup is more favor the stability than the downward setup, isn't that right? So the Egret is having the correct setup?
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Old Jul 16, 2012, 07:15 PM
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edwen303
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There is lots of room below on the Egret's nose gear to add on a rudder.
Thanks edwen for your kind words which helps my moral as the thread is almost seven years old.
I like the rudder on top to prevent ground damage but since the fuselage of the Egret sweeps upward, a lower rudder may work better being more at the vertical level of the CG.

edwen303
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If I have more time and spare parts, I might start working on J7W2, Shinden-Kai, the jet version of Shinden, with 70mm EDF.
I would love to see a successful fan powered canard because the power unit could be placed at the CG making it more stable. A few obstacles are: The power to weight ratio would be high which would result in short flight times and the necessity for a light air frame. Ground yaw stability would be lacking without a prop blast on the rudder. Both of the above would not favor having landing gear.
Foam models are best suited to EDF power because they would be lighter. My recent interest in the style was lost because it did not fit my building methods.

Charles
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Old Jul 17, 2012, 11:25 PM
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Charles, it will depend on relative spans and moment arms. Because canard spans are normally small and the moment arm tends to be big, yaw dominates in almost all cases. If the canard dihedral is so flat that there isn't much, if any, yaw, then generally it doesn't do much of anything. If the canard span is long enough compard to the wing, such as on the prototype VariEze, you can get roll control from the canard, but it tends to be weak. Rutan tried it, flew the plane with elevons on the canard, didn't like it, and quickly changed the plane to ailerons on the wing and elevators on the canard.

There are exceptions, but they get into some truly bizarre territory.

Best bet is to experiment with some small FF gliders. Use aluminum foil or soft wire for hinges on the control surfaces so they can be set for various deflections, then see what works..
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Old Jul 18, 2012, 12:52 AM
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do you mean like this?
phase one (6 min 26 sec)
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Old Jul 18, 2012, 02:14 AM
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Don Stackhouse
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Best bet is to experiment with some small FF gliders. Use aluminum foil or soft wire for hinges on the control surfaces so they can be set for various deflections, then see what works..
I like that idea Don, if the glider performs well then so does the scaled up version as all that I have tried.

Captain, thanks for showing your twin fan sailplane. It looks like a great set up.

Charles
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Old Jul 18, 2012, 04:14 PM
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edwen303

edwen303

I would love to see a successful fan powered canard because the power unit could be placed at the CG making it more stable. A few obstacles are: The power to weight ratio would be high which would result in short flight times and the necessity for a light air frame. Ground yaw stability would be lacking without a prop blast on the rudder. Both of the above would not favor having landing gear.
Foam models are best suited to EDF power because they would be lighter. My recent interest in the style was lost because it did not fit my building methods.

Charles
I noticed my Shinden didn't have ground handling, now you reminded me: no propwash on the twin vertical stabs!

It is true foam plane build is completely different from the balsa model, which I can only envy about. I prefer sculpting over sheet/glue scratch build. I have a few foam jet, its seems 150 W/lb is the minimal power/weight ratio as against typical 100 W/lb for propellor plane. This means if my Shinden remains at around 2 lb, she would demand at least 300 W (> 20 Amp for 4s, > 30 Amp for 3s).

My Shinden has off-scale large wing, which means too much drag for jet. I wouldn't expect much speed she can get as EDF model. I would definitely go with high thrust EDF setup, at least 64mm EDF.

Here is my underpowered GWS B-2 take off and fly in a breeze: (thrust: weight ratio is barely 0.5). She will NOT take off if running 1000mah 3s battery under 20C.
Here is how my underpowered GWS B-2 took off and flew in a light breeze.
RC GWS B-2 bomber (4 min 20 sec)
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