I rescued 50 year old Berkeley F11-f1 ".020 "duct-fan" model. Tried when I was 12 or so, some 60 years ago. Did ya ever want to re-build a kit because you knew more and could do it justice now? Well that is my goal. Ahh, back to the old Berkeley "Tigercat." The original kit was designed very light, and the aluminum fan for either an .020 or .049 is three (3) inches in diameter. A "Buzzing" glider!
My intention is 3 fold. 1st., I want to copy all formers and parts from the di-cut sheets. I would even like to use some dental plaster to save a "pull" or male mold for the canopy and shroud for the original concept of .020 or .049 duct construction. I have made a template of the aluminum fan and it shows where stop/rip holes are necessary. A side-view shows the convex form and I have miked the thickness. Not that many would like to engage in the original concept of propulsion. I want to save some history. I want to submit copies of he dicut formers and ribs back to "Hippocket.com" to "pay ahead' for all the enjoyment I have had looking at plans and copying airplane plans I will never build but give me endless joy and memories looking at them.


The second phase would be an exact build with an .020 or .049, silkspan covered wings and removable landing gear. It would simply be a build of a kit by an experienced man and a well finished model hanging from my office ceiling.


The final effort would be building the plane around one of your fans and the electrical systems including small park-flyer retracts. 1/32 covered wings and recreated decals. This effort I envision rc with small servos and pull, pull systems. Wing "directional flaps" since this plane didn't use ailerons. Full house and possibly a overall size increase to keep the weight per square inch in the "easy to control" range. Nothing big, just a slight percentage increase if necessary.


I have to build this last one literally around the fan, gear, batteries, speed control, wheels and batteries. A collection of these components will give me the math for wing loading; glass or paper covering of the pre-paint model. This is when an original 25" wing might be enlarged to 30" for a nice wing load.


My fan in the original 25" kit is 3" in diameter. I make no bones that this is a transition and learning process for an internal combustion 2 and 4 stroke guy. A small plane has been 40 inches. This is a concept and if it works in the "Beta" form, I wold like to build a clean documented narrative for submission to Model Avation magazine. Both Berkeley and Comet kitted a few of these "duct-fan" kits.


Thanks Kep

2 inch is about 50 mm, and 3 inch is about 76 mm. there is a good selection of very efficient fans in these ranges. i fly some 450-500 gram stuff on 50 mm XRP fans with 2 cell lipo. as do many others. take a look at the micro edf jets and power systems, and scratch built edf sections of the forums over at the groups for a lot more info.

mongo

Thanks Mongo.