Thursday, May 12, 2016

Hot Curve on Foam Plate Model Plane

No one I know has more passion for promoting the simple rubber power and glider free flight models to anyone that might show interest than Neil Dennis aka wombat. It seems wherever he goes he is trying to give a model to someone that might have children in their lives that might like a model airplane. In 2013 I had written about Neil but recently he had sent me some foam wing panels that he wanted me to try in a model.

What makes the panels unique is a curve was permanently put into a section of foam plate by heating the foam that was in a jig. The resulting foam section has a perfect curve to it without the bend marks and it feels more rigid than panels shaped by bending. In the following text, Neil describes the process:  

“For the warped foam, I cut two of the airfoil shape I want in pieces of 1 x 4 pine on the band saw, that gives me the top and bottom of the jig.  Then I cut a piece of aluminum flashing about 1" wider than the blocks, bend a right angle lip on each side (that stiffens the sheets so they hold the shape) and staple them to the form blocks. This makes a light metal jig with the "foil shape.  I use hooks and eyes on each side to clamp them together, two tiny screw eyes on each side with a 1/32 music hook to clamp the jig together.  The foam blanks will bend with no trouble. 

I "cook" the loaded form in the oven for about 10 min at around 200 f or a little less, let the jig cool and Voila, a warped wing section!!😉”    Neil Dennis

From the foam sections Neil sent me I built another Fantastic Foam Flyer but rounded the corners of the flying surfaces some.  I have flown this airplane many times and it flies great, but as of yet I have not done flight time testing to compare the stock FFF airplane. My observation is the new plane flies slightly slower. When the airplane goes into the glide phase it begins to stall right away and the entire glide down is a series of small stalls with recovery. I am thinking slightly less bend in wing would be better in the glide.

It is great to see innovation in small foam model airplanes, great job Neil.

Update 5/19/2016

The advice I was given to move the wing back which moved CG ahead was correct. I also had to shim up the front of the wing slightly. There is no stall in the glide at all now.

Bill Kuhl

Related Links

Neil Dennis - wombat

Fantastic Foam Flyer

Slime Recovery of Foam Airplane  - my tale of retrieving from swampy pond

1 comment:

  1. A second and third thought on the slight dipping stall. Other than changing wing form is first I am sure you know but others may not. Center of gravity maybe slightly tail heavy. A dab of clay up front or move wing back ever so little. Seldom used on such small models but you may find to be best reamdy is a lifting tail, a airfoil on horizontal stab. Common free flight design.