Another Briggs & Stratton conversion

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TiPi

Well-Known Member
Log Member
Joined
Aug 25, 2019
Messages
244
Location
Mackay (AUS)
This is a conversion from Norbert Schwarze in Germany, based on a 38-series B&S
http://www.flying-directory.com/popup_info.php?action=aircraft&id=5096
Not sure if these engines are still being built, Norbert has retired and handed his business on to other people.
The better known converter is Bautek (bautek.com) but no info on the engine in English and very little in German. Also based on the 38 with redrive.
 

karmarepair

Well-Known Member
Joined
Jan 13, 2011
Messages
77
Location
United States
This looks like the smaller Briggs, series 38, with a reduction gear on the PTO end.

Your browser probably translates, but this is what Google says for me:

BRIGGS & STRATON engine mount - Hans ENGELS

To equip his HM-163, Hans ENGELS chose the Briggs & Stratton 4-stroke engine converted by Norbert SCHWARZE. But it turns out that amateurs have suffered from cylinder head gaskets failures with this powertrain. Before putting this engine on his airframe, Hans first focused on analyzing the forces caused by the Schwarze frame on the B & S twin, then he made a montage of a nature to avoid problems. The following is a good example of what to do before building an accessory that is not on a plan: STRUCTURAL thinking .

All the propeller thrust, vibrations and engine torque reaction and pulsation pass through the cylinder head (and its seal), because on each cylinder head there is a silent-block <<RRY - read "Resislient mount">> located at the same height as the propeller axis.
The 2 x 2 silent blocks at the bottom carry the weight of the engine but are not sufficiently wide apart to compensate for the engine torque.

When the engine speed varies, the upper part of the engine moves laterally by more than one cm. This effort is taken up by the silent-blocks on the cylinder heads. Naturally, the head gaskets also cash this effort.
Thus the cylinder head gaskets absorb the forces due to propeller traction, engine speed variations, engine torque, and vibrations. But they are not designed for that! The Schwarze motor mount seems to be avoided.
The pictures are instructive. Herr Engels added a triangular vertical support to the bed type motor mount, and tied it into the reduction drive framework with a big-ass piece of all-thread with Barry Mounts at either end. And got rid of the resilient mounts to the heads.

It depends on the engine, but this could be an illustration of the downside of driving off the PTO end - that's where all the good tapped holes in the case are, to work out your engine mount.

Norbert Schwarze is a big cheese in European ultralights, and at one time made trikes, and it looks like paramotors?[/QUOTE]
 
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