I'll take Bernoulli over Newton any time.
A very close friend of mine and president of our EAA chapter was one of the de facto "reverse engineers", machinists, and builders of the only fully functioning "rocket belt" civilian jet pack. A group of people built an exact copy of the Bell jet pack of the 1960's. It ran on near-pure peroxide reaction "jets". This is the one from the James Bond movie and appearances in many TV and sports events. My friend went on the 1990's Europe tour with Michael Jackson, where the rocket belt was used to simulate Jackson's stage exit after the show.
The peroxide was very dangerous and required a team of people to manage it, hazmat and all that. But the interesting thing my friend told me was that once you had a safety system in place to prevent anyone from getting burned or blown up by the peroxide, it was actually 100% reliable as a power source. Meaning it would never throw a rod, swallow a valve, have an ignition failure, flameout, etc.
When we spoke about using ducted fans and jets for a modern personal flying device, he reminded me about the tradeoff. A piston engine may not take as much training or support to operate, but it has far more failure modes and far higher chance of an engine failure. People think they are making a safer alternative by using the jets or piston engines but they are replacing a 100% reliable power source with a far less reliable power source.
That Martin Jet Pack is a brilliant device, but it is not a flight device. It is a specialized device that activates people's fantasies and dreams as a method to extract money. It is the same as the Moller flying car and a hundred million other things that would have to defy physics to work. 200 horsepower out of an engine the size of a Big Mac. Plus transmissions and gears and drive shafts and lord knows what else to drive tiny little blades with no Reynolds numbers. Give me a !($*% break. The Hiller Flying Platform, Avrocar flying saucer, and several other possibilities have abetter chance of an average housewife taking one to the grocery store. That silly Terrafugia flying car can be worked out and legitimized with less risk and tribulation that a ducted fan pack. Look up the SoloTrek if you want to see the future of the Martin Jet Pack.
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