Canard Forum: Show,Discuss, Learn - Page 203 - RC Groups
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Aug 29, 2009, 10:56 AM
DreamArcher's Avatar
I have to work this morning for server maintenance for 4 hours. I'll post some pictures later today. Really the objective of being really small and the CF tube are the only things in common.

30" WS, the tiny 12mm GWS direct drive with a 3x3 prop.
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Aug 29, 2009, 11:38 PM
DreamArcher's Avatar
Finished up and flown. It's been a goal on-and-off over the past several years to be able to fly in my 30x50 backyard. I didn't have time to perfect it but this plane did 3 laps in a single flight so I'm calling this goal successful. I ran out of light and I know there was at least a couple piles off poop so I didn't want to risk it. hahaha. I'll try to get some video tomorrow.

No camber but it ended up being a nice floater. All the controls were a lot more responsive than I expected so I used the D/R. Tomorrow I will change the throws.
Aug 30, 2009, 01:12 AM
"Hobby Apparatus" Flyer
Mikey C.'s Avatar
Wow man, that looks super nice! Grats on the maiden. Cheers~
Aug 30, 2009, 03:27 AM
Registered User
John235's Avatar
Dreamarcher, your slow-flyer looks very nice. It is great to hear the model has met its design goal. Canards are generally not the slowest flying model for a given size and weight, but the advantage is the predictable stall charactitics of a well designed model. I look forward to seeing the video.
Last edited by John235; Aug 30, 2009 at 04:28 AM.
Aug 30, 2009, 04:03 AM
Registered User
John235's Avatar
Originally Posted by Mikey C.
Question--Can you explain why would I want to move the CoG forward if I increase the canard surface area? I'm sure there's a good reason, but right now it's beyond me.
Mikey, increasing the size of the forward wing causes the neutral point of the aircraft to move forward. It is important for any model to keep the CG location ahead of the neutral point. This is necessary for proper pitch stability so the model can maintain steady level flight without continuous input from the pilot. Having the CG position ahead of the aircraft's neutral point is really just another way of saying the forward wing must have a higher loading than the main wing. To give a proper explanation of why this is necessary requires some maths which you could read about if you ever feel the need.

For models with a conventional layout there are some commonly used rules-of-thumb about the balance point of the model releative to the main spar, or some percentage distance across the wing chord. That approach makes some assumptions about the size and location of the horizontal stabilizer. The assumptions only apply to conventional models and will be totally wrong for a canard model. The correct way to determine the balance point for any model is to find the neutral point for the aircraft and then chose the CG location relative to the netural point. Rather than going though a lot of calculations by hand, there is a useful web calculator that can do the number crunching for you. It is here:

When using this calculator, static margin of 10% normally gives a good starting point for the CG location of a new model.
Aug 30, 2009, 05:35 AM
who has rabbit ears down
Captain Canardly's Avatar
Now that I have a dry basement, and time during some unemployment, I have given Haole's Jacknife some time.
with doing some rough weight and balances, I came up with 96" of sevo extensions to get the job done. I think this one will remain as a "phantasy" plane!
Aug 30, 2009, 10:13 AM
magic612's Avatar
Originally Posted by DreamArcher
It's been a goal on-and-off over the past several years to be able to fly in my 30x50 backyard.
I know the feeling! While it's not a canard, this plane I designed earlier this year flies nicely in my 40' x 60' backyard too. Good to know there is now more than one design out there that will accomplish that "fly in a small yard" goal, Mike! (Without being a "micro" plane, that is.)

Will you be posting plans if it continues to be successful for you?
Aug 30, 2009, 01:06 PM
DreamArcher's Avatar
I remember you showing me that before. I like it. I might make one of yours next. I've been holding off a little until I bought a couple 6g servos and 360mha batteries.

It's been a long time since I've flown a rudder controlled plane. I forgot how much fun it is.
Aug 30, 2009, 08:23 PM
DreamArcher's Avatar
I just went off experience from several larger canards I've built in the past but just plugged my numbers into the cg calculator. It says I have a static margin of 20%. It says between 5% and 15% is typically good so I might shift it back a bit to get a slightly slower flight speed.

Finally have time to fly this afternoon but the wind is pretty aggressive this afternoon. Typical. It might be doable since we have tall trees at the back and our house is two story. What I'd really like to do is take it to a park and get it tuned in and get used to it before much more flying in the backyard. I already nosed right into the side of the house once. hahaha.
Sep 01, 2009, 12:34 PM
DreamArcher's Avatar
Plane flew well at the park this morning. I was just getting into the groove and was going to move the battery back on the next flight. Too bad it only lasted 5 minutes until the motor got cooked and stopped. Since it was so hot I suspect I just over prop'ed it with the 3x3. Normally I run these as twins in parallel on 1 esc so it's never happened before. I have a half dozen more of these motors so no worries. I guess I'll run the 4x2 that comes with it.
Sep 01, 2009, 05:07 PM
Registered User

Canard Loading

Mikey, The canard wing MUST stall before the rear wing to keep the model from falling backwards. If the front wing is made larger it must carry more load to assure that it will stall first. To add load up front, the battery or ballast must be moved forward. The weight per unit of area of the canard wing could be double that of the main wing. The main wing which may have three times the area of the canard wing easily carries it's load at a low angle of attack and must never stall. The canard wing carries it's heavy load at a larger angle of attack which further assures it will lose lift before the main wing when it is forced into a steep climb. You should be able to hold full UP elevator at reduced power and watch the model porpoise with repeated canard stalls. The main wing will always have good aileron response and plenty of reserve lift regardless of the lift problems upfront. A well designed canard model will have a gradual decrease in lift up front during steep climbs which will slowly drop the nose. Nose UP capability should be available at touch down.
Sep 01, 2009, 05:33 PM
DreamArcher's Avatar
Hey addict, do you recommend any up/down thrust for a nose mounted motor. Tie strapping my motor to the CF rod tends to allow it to move left or right several degrees so I'm going to make something a little more fixed tonight and I might as well put in some up/down if it will help.
Sep 02, 2009, 02:03 AM
What could possibly go wrong?
nickchud's Avatar

CoG calculator

When you've put your mind to that question Charles, here's another one...

My Starship has a very steep angle for the leading edge of the strakes. The width of the fuze means that I can get very different measurements for the CoG calculator depending on what is meant by the "root" of the wing.

Looking at the drawing, AA, YY, SS and D will all depend on whether I measure from the junction of the wing and fuze or from the centre line of the plane. What would you do?


Last edited by nickchud; Sep 02, 2009 at 02:09 AM.
Sep 02, 2009, 02:35 AM
Stranger in a land
Haole's Avatar
Originally Posted by Captain Canardly
Now that I have a dry basement, and time during some unemployment, I have given Haole's Jacknife some time.
with doing some rough weight and balances, I came up with 96" of sevo extensions to get the job done. I think this one will remain as a "phantasy" plane!
Sorry for dropping the ball on making drawings for you guys--been super busy with 'real life' crap, heh. Yeah, Capt, I figured the real model would have two receivers and 14 servos...

Leaving off the retracts (and landing gear altogether) would shave a lot of complexity off of the design though would probably make for some entertaining ground loops.

Sep 02, 2009, 06:08 AM
who has rabbit ears down
Captain Canardly's Avatar
Oh sure! another trick for the "ol' Geezer"- 2 receivers will certainly sort out one balancing hassle! I shall move forward with that in mind1