> *>This guy really gets around!
> *>He posted on the Soaring Usenet group on Google (rec.aviation.soaring),
> *>suggesting that his designs be used to power some of the lighter
sailplanes.
> *>Yeah right!
>
> Hey, you could use a V1 engine instead and get more credibility (and
> tinnitus). That Hiller trombone device has very low compression ratio so
> its efficiency is low. But so has the V1 engine ... there was someone on
> this list who said he flew a pulse jet model airplane some time ago, maybe
> they want to chip in on this thread.


One working model of Bruce's engine produces about 100 lbf thrust. The V1
produced about 600 lbf. Bruce uses his to power a gokart. Apart from the
terrible noise it would be an entirely practical sailplane motor. The V1
carried a 1 ton payload and travelled at about 400 mph. As air drag rises as
the cube of velocity a V1 size craft might be expected to exceed 200 mph
with Bruce's engine in level flight !!!!!!!! ((600/100)^0.333 ~= 1.8) A
smaller craft would go faster.

A jet or rocket engine of any sort has the interesting attribute of
producing more effective power with increasing speed due to the P = V x F
relationship. (At standstill it delivers no true power at all - only force.
At 200 mph a 100 lbf motor produces about 30,000 ft-lbf/sec or about 60
horsepower. Entirely adequate for a small craft.

Takeoffs would be another matter. The V1 had the same problem and used a
peroxide powered steam catapult to do the honours. In the case of a
sailplane the time honoured alternative is a car with a tow rope. Once
airborne the pulsejet would take it to altitude with ease. A photo shows
Bruce holding the 100 lbf unit and its not overly large on the Go kart. V12
consumed 3.5 lb of fuel per lb thrust per hour. Bruce's is, presumably, more
efficient.



        Russell McMahon

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