John Domenjoz Parachute Airplane (Domenjoz Artillery Spotter)

Grey Havoc

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http://blog.modernmechanix.com/artillery-spotter-has-vertical-lift/

http://www.rexresearch.com/domenjoz/domenjoz.htm
 

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Jemiba

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Interesting concept ! Tried to remember some mathematical formulas from the long gone schooldays.
This contraption may have a mass of about 200 kg , just as a very rough estimation ( Pilot, engine, cap,
fuel, emergency chute ...)? Then it has to produce a vertical lifting power of 200 kg, too, which would be
generated by accelerating air via the cap. Given the apparatus can accelarate air to the equivalent of
a gale with Beaufort 12 (about 33m/s) it would just have to pump downwards about 6 kg of air constantly,
roughly 7.3 cbm. Assuming a hemespherical shape of the cap, moment please ... a diameter of about
2.5 m would be enough ??? Can't believe it ! Ok, the thrust would be pulsating, so has to be much higher
to compensate for the interruptions and maybe 33 m/s is much more, than could be achieved. And it
probably would result in very severe vibrations and resemble not at all the swanning of a jellyfish !
And maybe I should have used my lunch break otherwise ... :-\
 

hesham

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From TU magazine,

this designer had earlier anther airplane of 1922,any idea ?.
 

riggerrob

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Why bother with a crankshaft?
A simple direct connection between the piston and valve would do the same trick.
 

Apophenia

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From TU magazine,

this designer had earlier anther airplane of 1922,any idea ?.

A bit late replying, but ... that 1922 John Domenjoz design was realized in his 1924 sail-glider. That machine was destroyed along with its hangar during a 1925 storm. Domenjoz repeated his effort in 1929 after he'd moved to the US. This US version of the sail-glider was flown ~10 times but the concept ultimately proved flawed. Domenjoz's US sail-glider is preserved at the Owls Head Transport Museum in Maine.
 

Aerohydro

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Nik

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That... Sorta reminds me of an infamous early ornithopter design, which flapped its wings enthusiastically, pogoed high and fell apart...
 
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