quorneng
Master member
Having built several planes in Depron I wondered if it would be possible to go 'up' the conventional weight/power spiral by building a big, light weight, low power scale 'jet' using a ducted prop rather than a commercial EDF.
In the Skyray Douglas squeezed the biggest jet they could into a small compact airframe so it looked a good starting point.
I began with this 40 year old 1/72 plastic kit!
A 4.5x4.5 prop driven by a 2600kV out runner gave over 16oz static thrust at 180W.
With a bit if juggling I could get a 4.5" prop inside a 36" span Skyray and stood a chance of keeping it below 16oz all up. Putting the prop in a duct would loose some thrust but it still looked feasible and just as important it would be cheap to do!
The basic centre section of the duct was made from 3mm Depron planks formed around a piece of plastic sewer pipe. Depron 'hoops' added to give it enough strength to be handled.
Fuselage formers were than added.
The underside was then skinned in Depron.
The top skin would only be added when all the RC gear was installed.
The wings had no ribs. the wing skins were simply glued over the wing spar and 2 spacer spars. This resulted in a perfectly symmetrical section and with a scale t/c ratio of just 6%.
The next step to build the fuselage nose section and create the bifurcated inlet. That was going to be much more complex operation.
In the Skyray Douglas squeezed the biggest jet they could into a small compact airframe so it looked a good starting point.
I began with this 40 year old 1/72 plastic kit!
A 4.5x4.5 prop driven by a 2600kV out runner gave over 16oz static thrust at 180W.
With a bit if juggling I could get a 4.5" prop inside a 36" span Skyray and stood a chance of keeping it below 16oz all up. Putting the prop in a duct would loose some thrust but it still looked feasible and just as important it would be cheap to do!
The basic centre section of the duct was made from 3mm Depron planks formed around a piece of plastic sewer pipe. Depron 'hoops' added to give it enough strength to be handled.
Fuselage formers were than added.
The underside was then skinned in Depron.
The top skin would only be added when all the RC gear was installed.
The wings had no ribs. the wing skins were simply glued over the wing spar and 2 spacer spars. This resulted in a perfectly symmetrical section and with a scale t/c ratio of just 6%.
The next step to build the fuselage nose section and create the bifurcated inlet. That was going to be much more complex operation.