First step was to make a foam cutter able to produce trapezoidal wings; it leads to this strange thing:
The brass rod follow the guide for the Clark YH airfoil:
Both axis are adjustable so that thickness ratio can be different at wing root and tip:
Brass rod and guitar tuner:
Guitar tuner for the hot wire:
Here it is, Clark YH section wing:
The position of each axis must be adjusted to compensate for the “melting gap” making the wing thinner than expected according to basic geometry:
Testing foam resistance thanks to 1 liter of milk (the wing weights 8 g):
Looks like the wing can be deformed a lot before it brakes (a video shows movements of the wing tips in turns with amplitude of 2 cm):
This is how I was cutting the wings with this old cutter; it’s quit the same with the new one).
First, draw large wing shapes:
Cut it with a simple gravity cutter:
Put the shape under the wing cutter at the right position (a whole mess):
Cut extrados :
Playing with sketch up:
The only plans I have:
Smaller “precision” cutter:
For the ailerons:
The wing of the first prototype, with unguided aileron rods (vibrations in flight):
Making guides for cutting the fuselage:
The new wing cutter, easier of use:
The first prototype with motor in position:
Here, I was estimating that the aircraft should weights 500 g in flight condition:
The motor mounting is very trash… here it’s 441 g almost ready to fly!
This pics was taken after the first flight:
Four days later… cold weather (4°C) makes foam fragile!
The wing hurt the cold ground, etc.
No problems! Back again, with paintings, 3 days later…
I expected gray not pink!
And stupid me! I forgot I had a spinner to put on that motor! 1 cm too far from the aircraft’s nose…
The karman is in adhesive paper tape:
One week later, crash on a soccer cage (stupid me):
(This aircraft was repaired and could fly again)
Improved aileron control rod (no vibrations):
Wings of the second prototype:
Cutting the curved parts that were missing on the 1st prototype:
The 2nd prototype:
Only 2 axis:
No (or very few) sanding was needed at this point:
The first proto is behind…
The air intakes:
The 3rd prototype (all parts cut in one day):
I had troubles with the 3rd prototype! A crash after hand launch while I was trying a bigger prop… repaired and back again.
I’m now trying to install the Elogger and pitot tube on it:
Tool for cutting the trenches:
An old aircraft!