Dyna-Jet story

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dynajetjerry
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Dyna-Jet story

Post by dynajetjerry » Fri Mar 05, 2010 4:52 pm

Well, Guys,
I've run into a snag concerning my D-J story.
I had planned to use many of the pictures and other material that had been given to me by Bill Tenney's widow and her son, David. Unfortunately, the present management of Curtis Dyna-Fog, Ltd., appears to be much offended by my writings and hasn't approved my inclusion of that stuff in my story. I've written to CDF in hopes of clearing up this disagreement but no one there has contacted me.
I can't afford to get legal advice from an expert on patent, trademark, and slander law but may have another way out. If I send these pictures to people who request them, separate from my story and do not include them as an intregal part, perhaps I will not be found to be engaging in illegal activities.
Anyone who might have worthwhile advice on this subject and who is active in this Forum, who cares to suggest where I might find help, I'll be grateful.
I want to get this story out there but don't care to risk a costly suit or other confrontation.
Any ideas?
Jerry
Louder is always better.

dynajetjerry
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Re: Dyna-Jet story

Post by dynajetjerry » Thu Mar 11, 2010 8:07 pm

Good news, Guys,
I've been on edge for no reason, as I just learned. I finally was able to talk to Dennis Roudebush at Curtis Dyna-Fog, Ltd. and he assured me his company had no objections to my use of a D-J brochure or other CDF material in my writings. What a relief!
My mistake was to take to heart the grumblings of CDF's past president, contacted by CDF with my material. He wrote a rather testy letter to me and I had no way of knowing that his comments were not, necessarily, the opinions of the present management.
I apologize to CDF and anyone else I may have misled into believing, as I did, that the Curtis company might hinder me in my writings. They are quite gracious and understanding, even commenting that they enjoyed my story (though they've not seen the final version,) and appreciated reading about the earliest days of what became CDF and tales of Bill Tenney.
I'll now finish up.
Jerry
Louder is always better.

tufty
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Re: Dyna-Jet story

Post by tufty » Thu Mar 11, 2010 8:35 pm

Woo-hoo!

And I think I speak for us all.

Simon

dynajetjerry
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Re: Dyna-Jet story

Post by dynajetjerry » Thu Apr 15, 2010 10:27 pm

Hi, Guys,

I'm still fumbling along with all the pictures for my "history" of the Dyna-Jet and hope to get some talented assistants who can help me "get off the stick."

A comment, if I may, on past discussions of multiple tailpipes for a pulse-jet. Aeromarine's experiments with such concepts (during research on a thruster for American Helicopter Co.,) showed that portions of the pipes can operate at vastly differing temperatures during ssustained operation. The surfaces nearest the engine's centerline recieve very little cooling from ambient air while those on the outside receive much more. The result is a difference of about 400 degrees F., causing the hotter portions to expand much more than those that are cooler. A consequence is severe curvature of the affected tailpipes. Thicknesses of the metal seems to have little effect in reducing such distortions. Also, it proved to be almost impossible to funnel enough air into the overheated areas to significantly reduce their temperatures without adding a great amount of weight and size and/or reducing useful thrust.

I am unaware of any truly effective cure.

Jerry
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Re: Dyna-Jet story

Post by Mike Everman » Tue Jun 22, 2010 2:25 am

Jerry,
I'm glad to hear that the road is clear for your story!
Mike
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Re: Dyna-Jet story

Post by Bruce Tharpe » Sun Jun 27, 2010 5:29 am

Jerry, that's good news about Curtis-Dyna and the book. Did you happen to ask them if they are currently selling the Red-Head?

dynajetjerry
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Re: Dyna-Jet story

Post by dynajetjerry » Sat Jul 10, 2010 3:21 pm

Hi, Bruce & others,
I was given to understand the D-J RH is still being manufactured but only in lots of 100 or more. The Curtis Dyna-Fog, Ltd. factory price is about $400 but some distributors sell them for much less. If none are in stock @ CDF, none will be available for sale unless an order for 100 or more is received by CDF.
I learned this information many months ago and some details may have changed. Please don't sue me if any of the above is out of date.
I'm still having trouble getting all the pictures together for my D-J book and sorting them out. My main assistance in this effort has been from the director of our local library; I'm nervous about taking up her time for this personal work even though she has assured me of her willingness to help, figuring it to be worth while.
Jerry
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Re: Dyna-Jet story

Post by 55dcyinely » Tue Oct 12, 2010 6:00 pm

dynajetjerry wrote:Good news, Guys,
I've been on edge for no reason, as I just learned. I finally was able to talk to Dennis Roudebush at Curtis Dyna-Fog, Ltd. and he assured me his company had no objections to my use of a D-J brochure or other CDF material in my writings. What a relief!
My mistake was to take to heart the grumblings of CDF's past president, contacted by CDF with my material. He wrote a rather testy letter to me and I had no way of knowing that his comments were not, necessarily, the opinions of the present management.
I apologize to CDF and anyone else I may have misled into believing, as I did, that the Curtis company might hinder me in my writings. They are quite gracious and understanding, even commenting that they enjoyed my story (though they've not seen the final version,) and appreciated reading about the earliest days of what became CDF and tales of Bill Tenney.
I'll now finish up.
Jerry
I worked briefly with Curtis Dyan-Fog, LTD on a project related to mosquito pest control. I spoke to Webster Peterson, nice guy great people and very helpful.
sometimes all it takes is a change in Management.

Webster Peterson
Corporate Manager and Chemist
Aire-Mate, Inc
Curtis Dyna-Fog, Ltd.
Midwest Sewing
1 800 544 8990
Fax 317 896 3788

Thanks Again Jerry
Doug

dynajetjerry
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Re: Dyna-Jet story

Post by dynajetjerry » Sat Mar 19, 2011 1:45 pm

Hi, everyone,

I'm not aware whether the word got out that, last July, I was involved in a nasty car accident and have been unable to continue my efforts here and on my D-J book. Sorry. I'm now getting around more though I stay with my helpful nephew and his wife. I hope to return home in a few weeks or months but must be very cautious because of weak legs; I have stairs to climb and might have trouble. I've returned to work on my book but only in fits and starts, right now.

The p-j Manalo was asking about appears to be a 1947 Dyna-Jet. I can't be sure it is an original because of the installed 1/4-32 glow plug. All original D-Js were equipped with 3/8-24 spark plugs, necessitating a hole that is too large for a standard glowplug. All later and current D-Js position the plug about 3/4 in. from the front of the combuston chamber.

The comment that a revised valve retainer can extend valve life is true but only if the valve lift and stress is reduced. This will also reduce thrust, objectionable if a modeler plans to install it in a flying model. In fact, Jet Speed modelers often increase lift, being willing to aggravate wear and tear on the valve and head in order to get the greatest possible speeds.

Thanks for everything.
Jerry
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Re: Dyna-Jet story

Post by Mark » Sat Mar 19, 2011 5:00 pm

Hi Jerry and welcome back,
Can you say what were the findings of reed valve thickness, what thickness the Dynajet uses or experiments in that direction?
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dynajetjerry
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Re: Dyna-Jet story

Post by dynajetjerry » Sun Mar 20, 2011 2:31 am

Mark,

All production Dyna-Jets used .006 in. thick blued steel for their reed valves. I have a few (with retainers,) but never analyzed any of them. I suspect that the D-J group evaluated several thicknesses, alloys and their hardnesses before settling on the production versions. However, I recently came across recommendations (NOT from Curtis Dyna-Fog, Ltd.,) that call for .008 in. and/or .010 in. spring steel. Perhaps these are intended for specific applications because I'm pretty sure the chosen material represented the best compromise for most uses.

Jerry
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Re: Dyna-Jet story

Post by Mark » Sun Mar 20, 2011 4:47 am

Thanks Jerry. I hope you can finish your book one day. You write well and I think many would enjoy reading and learning the Dyna-Jet story.
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dynajetjerry
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Re: Dyna-Jet story

Post by dynajetjerry » Tue Mar 22, 2011 12:56 pm

Thanks to all who sent their good wishes. I go to physical therapy twice a week but expect my insurance and/or Social Security payouts to end, soon. If/when that happens, I'll have to stop such treatments because I can't afford their costs. However, they have been helpful even though my improvements are few and disappointingly slow. As one of my earlier therapists reminded me in November, "Hell! You're 83 and can't expect a rapid recovery." Most of the weaknesses in my legs are due to my being idle in hospital beds for 2 months. During that time, my strength faded away even though my internal injuries gradually got better.

I guess I should be thankful I'm as well as I am and that the lady who ran into my Caravan (I pulled out of a side road into her path,) was harmed very little. It is appropriate that my difficulties have been much, much worse than hers.

Again, thanks.

Jerry
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Re: Dyna-Jet story

Post by PyroJoe » Tue Mar 22, 2011 5:50 pm

Hi Jerry
Good to see you back, cant wait for your book to be printed.
I have a question about the Aeromarine's 8 in., 205 lb. thrust pulsejet.
Did it have a profile that appeared more like a standard Dynajet or did it have a longer cone transition like the Argus?
I haven't seen any photos or dimensions of that particular engine.

Thanks
Joe

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Re: Dyna-Jet story

Post by dynajetjerry » Tue Mar 22, 2011 6:41 pm

Joe,

Aeromarine's 8 in. dia. p-j employed a unique valve head ass'y in that the reeds were vaguely similar to those on the Argus and the later Globe/Solar PJ32. A significant difference was that the Aeromarine design employed flat and slotted reeds, not pre-curved. The most-tested version was 8 in. dia. along all its length except for the dischage flare. There, its dia. expanded to about 9-1/2 in. (I still have 2 experimental pipe ass'ys for that version but no valve ass'ys.) Also, it utilized 2 separate fuel injector systems; one was in the inlet venturi (D-J style,) and the other had 8 injectors inside the combustion chamber, immediately downstream from the valves.The latter were fed by one piping system.

One apparent advantage of that design was the cooling effect on the reeds by the upstream injector. This resulted in a much longer duration of operation than then-contemporary but similar designs, being as much as about 10 hours, statically.

Another advantage was fuel economy. One tested example consumed as little as 1.9 lbs. gasoline for each lb. static thrust at about 200 lbs thrust. (Contemporaries burned as much as 3 lbs./lb. thrust.)The engine weighed about 50 lbs. when fabricated from .062 in. thick Inconel and was about 8 feet long.

I have patent drawings for it and hope to include them in my Dyna-Jet book. In fact, I supplied a full set of those drawings to NASA at the time I watched the running of (my) PJ32 at Wright Field in 2004. They were doing research on Pulse Detonation Engines.

Jerry
Louder is always better.

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