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AP Kwak - the Mighty Mini Foam Board Mod of the Jupiter Duck

#89
Can anybody share information on if they had any CG Issues; and how they compensated for it being tail heavy? It appears from my build a considerable amount of weight is needed. I'm using a 3 cell 850 all the way forward and 90 degrees to the fuselage. I already moved the motor forward with the nacelle plan addendum.

Is what I just described normal for this plane?

I have not attempted the maiden flight yet as I being extra careful not to damage it before I check with others first. My RC Club has a float fly this weekend and this will be my first opportunity to fly off of water.
 
#91
@wrangler90
How many grams of extra weight do you need in the nose? What does your battery weigh? If you have a CG-scale, please put the Kwak on it (ready to fly) and take a picture of the side for us.
2 ounces of wheel weights work. not sure on battery weight as I do not have a scale but the battery is a 3 cell 850 and it is all the way forward. ill send a picture of the side.
 
#93
It looks like the heavy white foam. If you don't have a scale, then you can't check the weight of one sheet of foam and you cant check the all up weight (315 g | 11.11 oz) of the plane. The only thing you can do is to check the center of gravity with two fingers again. It is 50 mm behind the leading edge of the wing. It is also marked in the plan. I hope that your Kwak will not be too heavy for the first flight. Have fun!
 
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#94
It looks like the heavy white foam. If you don't have a scale, then you can't check you cant check the weight of one sheet of foam and the all up weight (315 g | 11.11 oz) of the plane. The only thing you can do is to check the center of gravity with two fingers again. It is 50 mm behind the leading edge of the wing. It is also marked in the plan. I hope that your Kwak will not be too heavy for the first flight. Have fun!
Thank you.
 
#97
My first attempt at flying the kwak, I could not get airborne. So I burned a battery just water skimming. It’s been just sitting in the garage since then. I was building a replacement simple cub and got to thinking. Below is what came out of that. A kwak with a simple cub wing. It looks so cool that almost don’t want to fly it, but I will.
View attachment 230279 View attachment 230280 View attachment 230281
Finally got a chance to maiden today. The controls need dialed back. The rudder and elevator are very sensitive. Took off of the water with just throttle. I got too close to the trees and turned too quick and lost control. Going to reduce the throws and add more expo.