3D Passion 3D
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While this is a great flyer, IMHO it has a design flaw that the builder needs to correct before the first flight.

The leading edge of the elevator control surface ( where the CA hinges go into ) and the trailing edge of the non-movable part of the elevator ( again where the CA hinges go into ) are made of a SOFT balsa.

With the large control surfaces, the balsa will rip out in NORMAL flight.

This area needs extensive hardening.

Do this BEFORE assembly.

If you do not wish to remove the covering, the easiest way of handling this, is to poke pinholes into the wood all along both the upper and lower surfaces of all four areas. Then apply thin CA to the pinholes until the CA beads up. It should immediately begin to soak into the underlying wood.

Once this happens wipe off the excess CA with a rag soaked in acetone. You may then need to regouge the CA holes, etc.

Also consider using something other than the supplied CA hinges. The supplied hinges will dry to a SMOOTH finish when coated with CA.

Also consider sealing all of the hinge lines. Clear monokote works well for this.



I had the stock elevators rip out in flight TWICE.

The first time the elevator turned into a "tiller". After a harrowing few minutes I was able to get the plane down safely.

A week later I was back at the field with a repaired plane, and the same thing happened yet again.

Fortunately once again I was able to get the plane down safely, but these areas were now well chewed up.

I have since replaced the software balsa with hardwood shaped to the original configuration, and recovered.

This has held up rather well.

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Edit:

This "fix" has permitted me to fly the heck out of this plane very reliably.

I no longer fear tearing out the tail.

With a T.H. 75 engine this thing will NOT come down even at full engine idle!

I need a LOW pitch prop with it...