evans@mhuxt.UUCP (crandall) (10/04/85)
Somehow I think there may be some major problems with a pulsejet powered jetbelt. I have had some experience with model airplane pulsejets as a teenager and note that they are extremely inefficient as well as VERY noisy. In the model airplane incarnation (the one we used was known as the Dynajet Redhead wt was about 20 oz and thrust about 50 oz) these got very hot (no moving cold air) and wold get cherry red if you didn't launch in about 10 seconds. Getting them going was quite an experience - pump air into them with a big tire pump, hit the ignition (an old ford spark coil in our case) and head for the center of the ukie circle. They weren't very fast, but you could attract people from miles around. The H2O2 jet belts aren't new - Bell flew them in the early 60s (I believe the movie debut was Thunderball). I have been trying to get info from Williams Research (gas turbines for cruise missles) about their machines from the late 60s and early 70s. If anyone has any information as to the current state of the project I would be very interested. (they certainly aren't doing anything now). For those of you who don't know about the Williams/Bell jet belts they can best be described as fiberglas corsets with an inverted 400+ pound of thrust turbofan pre-cruise missle engine. Two large ducts redirected the thrust downward and control was similar to the eariler H2O2 rocket belts. One interesting feature was a mortor deployed parachute to counter the 0.0 L/D of the craft at unstart. Fueled up the craft weighed in excess of 200 pounds, but this was no problem as idle made the thing easy to "taxi" (one pilot claimed that the best fun to be had with the turbine belts was to get a thrust setting where you could do great 100 foot leaps like a kangaroo...) Again - I would appreciate hearing from anyone with any info on such schemes as I collect the stories. One of the biggest snakeoil jobs was a fellow who was going to build one with a ducted fan powered by a turbocharged snowmobile engine. -- just when you though Jim Bede held the record... :-) Steve Crandall ihnp4!mhuxt!evans