Piper PA18 Super Cub built by Peter Hauser

Engine:
Titan ZG 45SL
with Piper HMS and stainless steel silencer.

Weight: 9 kg

Piper PA18 Super Cub built by Peter Hauser

 

Mr. Hauser wrote the following interesting letter August 1998:

Toni Clark practical scale GmbH
Zeiss-Straße 10
32312 Lübbecke                                3. August 1998

 

Hello,

with this letter I wish to thank you for your superb Piper kit. This is my first large model, due to my very restricted free time it has taken me almost 2 years for completion and ready to fly. The more than excellent instruction manual plus the very easy to read plans is very helpful. The Piper has now been flown for some weeks with the ZG 45SL and the Hydro Mount System, and more recently the Easy Start System. Now with a hot engine, starting is a lot easier.

In the beginning I had to really exert myself to get the kite down, as I could not throttle the engine low enough. I had too much play in the throttle Bowden cable, which I had laid around the front of the engine in a 180 degree bend. Any Bowden cable that is fitted with a 180 degree bend has a wide dead spot between pulling and pushing which automatically causes play to develop. This dead spot and subsequent play is considerably reduced with a 90 degree bend, the springiness lays with the Bowden cable outer tube. Your recommendation is absolutely correct and must not be altered in any way. Perhaps you can add a few words to your building manual explaining the disadvantages of altering the Bowden cable layout. I have seen many HMS equipped models with the Bowden throttle cable laid around the front of the engine which led me into copying this mistake. I would guess a few of these modellers are sweating profusely on the finals ... or later in the modeling room ...

I have included a few photo's of my PA18 Burda Piper; that you can add to your pin board in case you have such a thing. I have painted the whole of my Piper with the exception of the cowl, with a foam plastic sponge roller. Using cheap normal alkyd resin paint warmed on the kitchen hotplate which has proved to be very successful. The resulting paint finish can be kept to an absolute minimum reducing all up weight (9 kilos ready to fly). Spraying is better, but many modellers do not have this amenity at home. Last winter I rolled side for side with enough stand down time between in a "requisitioned" room in the house and one can not see any difference to a sprayed surface. Maybe this is a helpful tip for other modellers

Best regards,
Peter Hauser,
Rottweil,
Germany.

Our thanks to Herr Hauser for his valuable tips.
On the subject of the throttle linkage a further important point from me:

The Bowden cable should be connected so the throttle lever return spring causes the throttle lever to press against and not pull on the Bowden cable. Due to the vibration induced swinging of the 90 degree bend the Bowden cable is thrown outwards, similar effect to a skipping rope, when the return spring pulls against this movement the tickover speed will fluctuate considerably. One time is the return spring stronger and pulls the Bowden cable inwards, another time is the rpm altered and the swinging is stronger (resonance effect) and the Bowden cable is thrown outwards. This immediately raises the tickover speed. When you then throttle down the engine it stops as soon as the return spring gains the upperhand.

Gerhard Reinsch.

Piper PA18 Super Cub built by Peter Hauser
Piper PA18 Super Cub built by Peter Hauser

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