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RE: Don't Get Tricked, Bro: How To Recognize an Investment Scam
I take back the claim that it is always tethered. Newer videos show untethered flight...but at the same low altitude. This bolsters my ground effect hypothesis imo.
It is also questionable whether ducted fans of the diameter shown are powerful enough to escape the ground effect limit given the much larger diameter of the ducted fans on the Martin "jetpack". Just my opinion though.
lemme see...
With an inlet velocity of 60 m/s a 0.5 m diameter (my dimension estimate) impeller can suck in around 11 kg of air. With an average exhaust velocity of 160 m/s (achievable by an average EDF) each engine has 1.7 kN of thrust. That totals to the total lifting capacity of 680 kg.
Of course given that is uses combustion engines exhaust velocities could be over 250 m/s and inlet velocities could be over 80 m/s which would mean way over 1t of lifting capacity.
Hm. Alright. I don't buy the insurance explanation though, otherwise we wouldn't have seen the Martin jetpack flying untethered at proper aircraft altitudes either, but we have. Something's fucky.
martin jetpack prototype isn't valued at 3.5 M$ + the company has better financial standings.
You see when new stuff being developed engineers are not the ones calling the shots, the financial department is