UH-10F Thrust Engine

This construction page shows the thrust system in its original form. This uses a Briggs and Stratton 21 HP Intek vertical shaft engine with a mule drive and 5V belt. This configuration turned out to be pretty cranky to get running properly (The 5V belt tended to jump off of the pulleys and the tensioner assembly failed), so I later switched to a 13 HP horizontal shaft engine. Pictures of the new configuration will be added soon.

Briggs 21 HP vertical shaft engine. These run very smoothly for a single cylinder engine.
Moeller marine 3 gallon ful tank and hose with primer bulb.
1″ stainless steel keyed shaft, pillow blocks, and upper pulley. This pulley is designed for a “B” belt, and though 5V belts will often work in “B” pulleys, the groove turned out not to be deep enough to retain the 5V belt. As a result, the belt tended to roll out of the groove.
Idler pulley tensioner assemblies. These are constructed from 1/8″ wall aluminum with 5/16″ tensioner bolts, which turned out not to be strong enough to hold tension on the belt. Steel probably would have worked satisfactorily.
This is the 42″ 3 blade Hascon fan I’ll be using for thrust.
This is the governor hardware I removed from the Briggs engine.
Cover temporarily removed to figure out how to attach the throttle cable.
I’ll be using angle iron to attach the engine to the craft. I removed the rubber shock absorbing feet after the first run as they allowed the engine to shift too much when applying tension to the drive belt.
The top part of the drive setup.
Again, with the fan removed.
This is the idler setup. The 5/8″ shaft was bent using an oxy-acetylene torch. Tightening the bolts on both sides of the tensioner setup pushed the pulleys toward the rear of the craft, increasing belt tension.
The angle pieces used to attach the thrust engine. These are bolted to the sides of the 1×4 rails.
The complete setup, before putting on the belt.
The tensioner assembly from the rear. Here you can see how the bent shaft allows the idler pulleys to accommodate drive and driven pulleys of different diameters.
The 5V belt is now attached
I’ll be using a motorcycle battery to start the engine. All wiring is now complete and the system is ready for testing.