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Micro ramjets? (RE: 'copters)
Hello All,
This week I received a copy of Jet Aircraft Simplified by Charles Edward Chapel (1954 Edition, Illustrated). In addition to jet airplanes and rocket planes, it also covers "tip-jet" helicopters, which were/are similar in concept to the model rocket mono-copters and the Jetex helicopters; these helicopters used pulsejet and ramjet engines mounted on the tips of their rotors' blades. This got me wondering: While model pulsejet engines don't appear to be workable much below the size of the Dyna-Jet Red Head engine, might model-size subsonic ramjets *not* be so severely constrained as regards their size? Would a small (say, 3/4" diameter X 1-1/2" long, or perhaps a bit larger) subsonic ramjet work as a tip-jet on a model helicopter? I imagine such a tiny ramjet engine wouldn't be very fuel-efficient, but neither were the full-scale tip-jet ramjets. However, for a simple F/F (Free-Flight) or micro-R/C model helicopter, a short engine-running duration would not only *not* be a problem, but it would actually be an advantage, since the model wouldn't fly too far away (either beyond the flying field boundaries, or beyond the effective range of the micro-R/C transmitter). Also: There are some good scale subjects for such tip-jet ramjet helicopter models--the Hiller-Hornet, the Hiller HJ-1, and the McDonnell XH-20 "Little Henry." Many thanks in advance to anyone who can shed light on this!
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#2
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I found an online version here: Jet Aircraft
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Quote:
The book--which is (as described on the dust jacket) organized so that it can be used as a one-semester course--is Jet Aircraft Simplified by Charles Edward Chapel (I'm presuming it's the 1954 Edition, Illustrated--there was also a 1950 Edition). Like all good books of this type, Jet Aircraft Simplified (which also covers ramjets, pulsejets, and rocket propulsion, including suborbital sounding rockets, rocket planes, and JATO units [Jet-Assisted Take-Off aircraft assist rockets]) also includes other things that are readily "connect-able" to school math, science, and even history classes. For example: Newton's three laws of motion and early jet propulsion devices (Hero of Alexandria's aeolipile, Wan-Hoo's rocket-powered chair, Chinese rockets, Isaac Newton's steam-rocket carriage, etc.) are covered. It contains the simple formula (with an example) for calculating the relationship between the thrust and horsepower of a jet or rocket engine. The gas turbine (jet engine) operating cycle (called the Brayton Cycle) is compared--in illustrations and text--with the Otto Cycle of reciprocating (piston) engines, and the turboprop (propjet), ramjet, pulsejet, and rocket (liquid- and solid-propellant) operating cycles are also covered in these ways. Simplified, illustrated schematics of jet engine fuel and lubrication systems are also included. And: The book also shows how to read multi-data graphs. On one page is a graph showing the changes in air pressure, temperature, and velocity through the inlet diffuser, compressor, combustion chamber (combustor), turbine, and exhaust nozzle of a non-afterburning turbojet engine. Another graph below it shows these parameters for an afterburning turbojet engine. The multiple graphs give a picture of what's going on inside these jet engines, and where. Plus: For drafting students, the book is loaded with three-view, exploded-view, perspective, and cut-away drawings of jet and rocket engines and the aircraft they powered, all of which they could draw from for practice. Print-outs of these drawings would be perfect for them to use for practicing scaling-up (or scaling-down) the drawings (including their complex curves), using the techniques in Paul Del Gatto's Jetex books (re-prints of which are available from Rocket Science Books, see: http://rocketsciencebooks.com ). I hope this information will be helpful.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#4
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Tip motor rotors were used on Rotary Rocket and the initial testing happened at the Rattworks shop locally!!
Tech Jerry |
#5
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Quote:
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#6
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Monopropellant HTP IIRC.
Quote:
Tech Jerry |
#7
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__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
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