Monday, October 28, 2013

Guillow's DHC-2 Beaver Flies & What I Learned the Hard Way

I think it must be human nature to go ahead and do something first and ask questions later.  That is my excuse for my Guillow’s DHC-2 Beaver free flight rubber powered model to electric power radio control project.  When I purchased I had intensions of building it rubber powered but there just appeared to be so much balsa in the structure that I thought it would be too heavy to fly very long.  To me the electric systems in the small RTF electric airplanes seemed so light and the motor was so powerful that a little extra weight would not be a problem.  After I started building I found the Stick & Tissue thread on Hip Pocket Builders Forum and found out that keeping weight to a minimum could be a real problem.

 When I just about had the airplane finished I tried advancing the speed of the motor and I noticed the propeller shaft was pulling ahead and the gears were slipping. The cowl had to be cut off to get at the motor and then the wires to the receiver were so short I had to cut a big hole in the fuselage to get it connected again.  At least I lengthened the wires after securing the back of the shaft so it would not come ahead. With everything put back together I tried flying it without charging the battery, it flew for a short time before there was not enough power to keep the motor running.  Charged up the battery and this time I tried to fly it the propeller was slipping on further inspection of the plastic gear the gear teeth were ground down. 

Plane Opened Up to Access Radio

The cowl comes off again and I put in a whole new motor/gear drive combination, the cowl is only taped on for now.  A wrecked Parkzone Champ RTF airplane was the source for all the electric components.  Yesterday the wind dropped just before the sun did so I took the airplane out to fly again and fly it did. The problem was if the airplane was not launched with a hard throw it would stall, once it was flying it flew fine and would maintain level flight at half throttle.   

With these observations in mind I did additional reading on the Stick & Tissue RC thread and found out how critical the weight is, the CG balance, and that some people use washout in the wing to help with stalling. My DHC-2 Beaver weighs 72 grams while the Parkzone Champ only weighs 38 grams, from my reading it seems that often the converted planes weigh 80 grams so I did pretty good.

For the next flying session I have removed the tail wheel hoping to move the CG forward and will try additional weight in the nose if I have to.  I have another Guillow’s kit that I plan to convert to RC, a Cessna 150 hopefully I can build that even lighter.  Like other people on the Stick & Tissue RC thread I finding making these planes fly well rather addicting.

** Update 10/28/2013 **

Removing the tiny bit of weight from the tail wheel improved the flying. I had a flight of 10 minutes on the 160 mah lithium battery, even did a loop.  As I have read weight removed from the tail makes a big difference in the balance.

My First Article on DHC-2 Beaver Conversion

Bill Kuhl

** Update 10/4/2014 **

Flying Inside Large Gym

Embrace the Challenge


1 comment:

  1. I was just flying the DHC-2 Beaver recently, still flying good. It will tip stall maybe I should try some washout in the wing. Not really a problem for me.