Kraft Bi-Fli
Posted: 06 Dec 2018, 22:42
A few years ago I was rummaging through the "used" loft at our LHS and came across a stack of 1950's and early 60's Model Airplane News magazines which I purchased.
In MAN October 1959 issue there was a build article on Phil Kraft's Bi-Fli biplane. It was being flown using three escapements controlling rudder, throttle and elevator, hauled aloft by a .15 cu in motor. I must have read that article 2 dozen times - probably more, I could not get it out of my mind.....plans at that time were not available.
One day while perusing Outerzone I found the listing for the Bi-Fli plan, promptly downloaded and had them printed off. Construction started immediately .. well in a day or so. I thought this would be a great model for my then recently converted single channel Ace Commander transmitter.
My workbench real estate is getting cluttered!
I have to admit I cheated a little bit (a lot actually!!) by installing proportional gear for the several test flights. Good thing I did or the "after Shot" might have had more pieces. I had to wonder how did they ever manage using only single channel to (a) keep up elevator to stop nosing over while simultaneously steering with rudder and also trying to Morse code throttle settings?
Some time later I found some you tube video of Mr. Kraft flying the Bi-Fli off a hard surface. All (!) he had to do was WOT and steer! Our runway is grass. I also found a later video of the MkII version with a much taller fin & rudder similar in shape to that on a Stinson 108-3. This version utilized 6 channel reeds.
I now have it ready & waiting for more for test flying using my converted Kraft reeds transmitter just in time for our annual 6 month ice age to set in.
I think I will find another project for multifunction single channel.
In MAN October 1959 issue there was a build article on Phil Kraft's Bi-Fli biplane. It was being flown using three escapements controlling rudder, throttle and elevator, hauled aloft by a .15 cu in motor. I must have read that article 2 dozen times - probably more, I could not get it out of my mind.....plans at that time were not available.
- Mr. Kraft cranking in the turns
- I made a set of ribs first
- Slapped them into my wing jig & glued in the spars etc.
- Rigging up the dihedral with the symmetrical airfoil and keeping it straight required some imagineering
- The fuselage taking shape & tail feathers completed
- I made a lot of changes in the nose area to accommodate a modern motor mount, fuel tank etc. At this point I was not sure about a .15 being able to fly this thing and needed an option to be able to change mounts if needed.
- All nailed together ready for covering. The fuselage is already covered with "00" silkspan & dope
- A "before shot" ready for test flights.
- The ground roll was all over the place like a dog sniffing for somewhere to.... Once off it flew quite well. Rock steady on the glide in.
- Here is an "After Shot" back on terra firma in one piece
Some time later I found some you tube video of Mr. Kraft flying the Bi-Fli off a hard surface. All (!) he had to do was WOT and steer! Our runway is grass. I also found a later video of the MkII version with a much taller fin & rudder similar in shape to that on a Stinson 108-3. This version utilized 6 channel reeds.
I now have it ready & waiting for more for test flying using my converted Kraft reeds transmitter just in time for our annual 6 month ice age to set in.
I think I will find another project for multifunction single channel.
- Choices to make...
). Plans are printed and LR3 put aside.