BACKSTROM EPB-1
PIGGY-BACK STUNT
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This idea won't give you a max flight
but should be a crowd pleaser that will make your Korda or Gollywock
stand out from the many. The following text is a summary of the
original article.
Thanks to the Web site of Zoe Quilter, www.fuelsoaked.me.uk. |
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"The actual mechanism consists
of a small spring between the nose block and the airscrew, to
the front leg of which is soldered a fine wire clutch, crooked
(hooked) at the end as shown...The platform on which the (piggy-back
model) is placed is made from 1/16" sheet balsa...To the
face of this, two wheel chocks ‘X' are cemented....a small
wire saddle is cemented to the rear end of the platform, the shape
of which is shown in detail ‘Y.' This engages with a slot
in the vertical fin of the model. The chocks and the saddle serve
to check the model from lifting (when) the larger plane is released.....The
platform is attached to the large (plane by means of hooks and
rubber bands, or simply glued down). When the larger (plane) is
wound, the spring is compressed and the clutch moves backwards.
The (piggy-back model) is then wound and fitted in place in the
chocks, with the (hook) end of the clutch behind the propeller.
This stops the (prop) from turning.. When the (mother plane) is
released and the motor runs out, the clutch moves forward, pulling
the (piggy-back model) with it....It then becomes detached from
the chocks and (rear) saddle, and the (baby) is off to a flying
start."
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| Of course, the piggy-back
model needs to be made as light weight as possible, and no larger,
probably, than 10" wingspan; having in mind an endurance model
of , say, 36" wingspan. Also, the entire installation should
be kept as close to the center of gravity of the mother plane as
possible. An interesting project, no? It will require some experimentation;
let us know the results. |
K-P ADJUSTABLE THRUST BEARING
It comes in the unassembled form shown. This came from
Skylake Models (present status unknown), priced at $2 each. The two
wrenches are for adjusting the thrust line; smaller wrench is for side
thrust, larger is for down/up thrust. We had a problem applying side
thrust after down thrust had been set: the down thrust adjustment changed
along with the side thrust. It is necessary to hold on to the down thrust
nut (#2 in the illustration) while the side thrust nut (#1 in the illustration)
is being turned. Use of wrench sockets, 1/4" and 5/16" sizes will help
in making these adjustments. Practice makes perfect. And a word to the
wise: these small wrenches are easily lost in the field. Although we
wrapped colored tape around them, one wrench was immediately lost. It
will be interesting to hear of solutions to these problems from our
intrepid fellow modelers. Let us hear from you.
SKY ARROW
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