Electric Ducted Fan Model


April 98 - By the way, the SilentRunner has a new power unit since some days. Though the ducted fan itself is still a Schwerdtfeger 89 mm, it is now driven by a Plettenberg 290/20/7 and 10 cells Sanyo 1250. Maiden flight was not yet (Easter '98) because of the bad weather.

Oct. 98 - The SilentRunner was flown in the meantime of course. The above configuration resulted in a usable motor running time of about 150 seconds in the beginning which increased to about 200 seconds in the meantime (as you know, batteries do not provide full performance when they are new). With an built-in telemetric system correct english expression ???) we measured a speed of 121 km/h. It seems there will not be much more possible because of the too large wing area (remember the construction is some years old), although the model benefits of the low-resistance airfoil MH30.

May 99 - Shortly I was asked for more details regarding the SilentRunner (really!) As usual, I will let pictures talk. I like to do so, as you sure know. :-) The photos were made while building above model (it is the only one, of course...) in Jan. '95. Here is how I made the fuselage, perhaps I'll do some more scans for the next update.

Right: a tower made of spruce and plywood... Bottom: the outside surface is balsa
Left: the inner channel surface is 0.4 mm plywood