Conic Valved Pulsejet

[gary]

Has anyone here experimented with or worked on a conic shaped valved pulsejet ??? This type I believe has a simple cone-shaped jet tube like that of the American Helicopter Co "Jet Jeep" from years ago.

A search of the archives here turned up zilch.

Attached hopefully is a picture from an article about the American Helicopter Co helo with the unique shaped valved pulsejet on the rotor blade tips.

Gary

[Vilkas]

Something very like Pulso-3 from Kritz?

[gary]

Somewhat like that Kriz Pulso-3 but a very simple cone from the valve area to the exhaust port. That type would allow a one-piece sheet metal (cone developement) to be rolled into a conic shape and seam welded (one seam only). I like the electrical resistance seam welding process vs MIG or TIG welding.

The sheet metal cone pattern is made by a "radial line developement" which is a drafting technique.

Gary in AZ

[dynajetjerry]

Gary,
An example of AHC's 1-man helo is at the National Museum of the U. S. Air Force in Dayton. To my eyes, it does not appear to be unique in its construction. Many similar p-js have been made over the years, in sizes from the Dyna-Jet to the 105 lbf Globe/Solar 10P14 of 1952.
During the winter of 1951-52, Aeromarine Co. (Dyna-Jet,) developed a p-j for AHC though the highest speed we attained with it (on AHC's whirl test equipment,) was 315 fps. It was valved and had 2 tailpipes and 1 combustion chamber. Static thrust was about 40 lbf but it fell off as its speed increased. I still have some paperwork and data on that p-j but the original example was sent to AHC where it disappeared when that Co. merged with Fairchild.
This and much more info is in my not-yet-complete book on the Dyna-Jet and its kinfolk.
Jerry

[gary]

Thanks Jerry,
The USAF Museum in Dayton is a really great resource. I visited it many times as a youngster growing up in Ohio. My late grandad Harshman grew up in that area and watched the Wright brothers test their kites and gliders.

I have seen the recent pictures of the AHC XH-26 "Jet Jeep" at the museum and yes, the pulsejets displayed on it were not conical shaped ones as in the above old photo. I've another photo of the AHC XA-6 "Buck Private" helicopter mounting similar conical pulsejets from the April 1951 issue of "American Helicopter" magezine, a very yellowed copy now. I'll try to attach it.

There have been rather conventional Argus-shaped pulsejets that used a conical exterior sleeve for added structural strength. However what I am after is data about a conical combustor type.

Guenther Diederich and the Argus engineers were able to squeeze 400+ MPH from their V-1 pulsejet motor. The design goal was to exceed the max speed of the Brit Spitfire fighter in level flight.

Gary in AZ

[dynajetjerry]

Gary,
I just returned from photographing the AHC XA-26 at the AF Museum. Its p-js are listed as having thrusts of 30 lbs. somewhat less than Aeromarine's version.
An unstated problem with such installations is the probability that, at operating temperatures, the jet pipes will distort due to g forces at useful rpms.
Question: Was your grandfather an early occupant of "Harshman House" and was Harshman Road named after his family? If so, what was his full name?

The Dyna-Jet was developed in the garage (or basement,) of that dwelling during the time Bill Tenney roomed there, 1944-1947. However, he hired Charles B. Marks, at that time, to help improve 2-stroke engines, calling his new company "Aeromarine Co." Charlie was fascinated by hearing a V-1 operting at Wright Field across Springfield Road, leading him to create several miniature p-js that led to the Dyna-Jet and other p-j products.

Thanks.

Jerry Wiles

[gary]

Thanks Jerry,
I've seen the pictures of the early Marquardt p-jet with folded/collapsed tail pipes from their whirl teststand in 1947. They developed rather short p-jets to try to deal with the centrifugal stress on the jet pipe. When Marquardt ended the gov't rotor tests their engineer, Corwin Denny left and formed American Helicopter Company to further develop p-jet helos.

Attached hopefully are some extracts of early helo p-jet engines from Marquardt and AHC.

My grandfather was Grover E. Harshman and lived in the Dayton home until his part of the family moved north before WW-I. His father died while Grover and his siblings were still children. The family name was originally Hirschman in Germany and dates back to the Holly Crusades as soldiers.

Gary in AZ

[dynajetjerry]

Gary,
Thanks for the information & pictures.I'll look into Dayton records and hope to learn a bit about your Grandfather Grover.
Jerry Wiles

[Mark]

If you type Jane in the search, there are a couple tip pulsejets from American. Maybe you can find a crumb there. Seems like I have seen that helicopter photo in Jane's as well.