I was going to go pick up some of that 1/4" foam at Lowes after reading a few posts on it. I have 2 KP-44's I want to put to use on it. I read Jason's post on how to make a wing w/ that foam but is there any way to make a fuse that sort of resembles a biz jet or airliner? Also is there any tips or links someone could give me? this is going to be my first scratch built foam model. Also I was thinking about the vibrations of the little EDFs and wondering if the fanfold foam could handle it. Thanks for your help.

vin

Hi Vincent,

As far as bizjet fuse goes,,,, yes there is a way, there used to be a link in a thread but the link is dead now.
The guys did a KP sized Biz jet and made his own shrouded cut down props, before the GWS 50 was out. He heat molded the Depron in his oven around wood plugs. The end result was very very nice and super light weight.
It is possible to make fairly round sections by heating the fanfold around a round object like a wood rolling pin with a heat gun, and then glueing the seam. Try to pick a good diameter like 66mm,,,,, why? becuase most spray cans and beer cans are about 66mm .

EDFs when balanced should have little vibration.

ok, Ill try heating the the fan fold around a spray can. I just downloaded the Profili program with the airfoils, which one should I use for a biz jet like this? Also I never really fully built a wing with ribs and spars ect... I just get the rib pattern, cut them out of the fan fold, glue them down the wing like your shown in your thread, then put a spar of foam all the way down the wing? About the KP-44's, previously I tried to convert a broken freeflight plane to EDF R/C but after I mounted the EDFs on the side w/ epoxy and turn them on with a 7 cell pack (wired in a series) that vibration was realllly bad. It seemed like a rotor was out of balence. but when I took them off and turned them on just being held in my hand there was little or no virbrations. Whats goin on here? and is there any way to take apart the KPs once theyve been put together? thanks for the help.

vin

Vincent, reference the shaping of foam try getting a block of foam (sometimes you will find them used as packing material) design a fuse, cut it out onto a material that will not burn with a heating wire (I used cardboard) using the cardboard as a tracing pattern cut the foam with the wire and finish the shaping with light sanding paper worked very well for me. (I designed a fuse' on Turbocad 7.0 printed it out and I've already done the steps above).

Opps!

Vincent, reference the taking apart the fan unit, take two or three pieces of string (I used three) place them around the fan blades and pull the fan away from the shroud. The fan is just pressed in.

As far as air foils go, just pick a simple one without to many curves,,, I use MH-43.
You can build the wing up any way you want to, I just showed in the thread the way I do it, fast and easy. For smaller planes, 280 size, I just glue a carbon arrow shaft or even balsa spar into the wing and fold the wing over it to get the air foil shape. Dont forget to tape the LE and top and bottom of the wing long ways.
I dont have an KPs, but it dose sound like one or both are out of balance, or perhaps you distorted the fan shroud when you glued them to the fuse ??????

ok ill try that airfoil. hmmm, now that i think about it i think i did distort the shroud when I epoxied it on there. is there any way to make a housing around the EDF (I forget the exact name of it) with fan fold? thanks!


vin

Most people make the shourd out of fiberglass, carbon fiber, or thin ply. Someting that is semi rigid to prevent distortion.

I wasnt talking about the housing, i meant like the inlet you build around the housing shroud. I keep forgetting the name of it.