A few questions for the new pressure jet builder

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Bruno Ogorelec
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Re: A few questions for the new pressure jet builder

Post by Bruno Ogorelec » Sun Sep 19, 2004 10:45 am

Simon,

I think we can safely forget the 300 lbs thrust claim. Loudmouth would be better known than it is if it approached that kind of output. It would at least have made the rounds of the popular mechanics and similar magazines.

tufty
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Re: A few questions for the new pressure jet builder

Post by tufty » Sun Sep 19, 2004 4:01 pm

Bruno Ogorelec wrote:I think we can safely forget the 300 lbs thrust claim.
I think so too. But you never know. Maybe we should get Viv and Luc on the case ;-)
Bruno Ogorelec wrote:It would at least have made the rounds of the popular mechanics and similar magazines.
Well, it made the front cover of 'Mechanix Illustrated' at least, it seems, I've been doing some delving but have been unable to come up with anything more concrete - no-one seems to have the offending issue 'online', and I can't even find one to buy.

Going from the names given in the eBay ad (Horton, Starner, Gahagen), I've been unable to find anything relevant in the patent system either. Cornis engineering only gives google hits for the one indycar race they entered. It's a frustrating search. The only one who seems to have any info on it is the eBay seller, and I'm loath to spend money I don't have on something I don't really need, and that I consider to be an unlikely performer.

Simon

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Re: A few questions for the new pressure jet builder

Post by Bruno Ogorelec » Sun Sep 19, 2004 4:29 pm

tufty wrote:I'm loath to spend money I don't have on something I don't really need, and that I consider to be an unlikely performer.
I agree with you. The basic idea does sound OK, though. I guess it could be developed much furter, but I don't think the guys who built it came very far in the development. Such endeavors tend to be frightfully expensive and people who embark on them usually run out of funds well before the product is ready for practical application.

As the Napier Nomad engine indicates, the compound machinery of this kind should perhaps have been explored further. I can see some neat engines born out of wedlock to the turbojet and the free piston engine. your sketch is just the beginning.

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Re: A few questions for the new pressure jet builder

Post by tufty » Mon Sep 20, 2004 6:31 pm

Bruno Ogorelec wrote:I can see some neat engines born out of wedlock to the turbojet and the free piston engine. your sketch is just the beginning.
Not a beginning, just one possibility. For example : attached is the ever-wonderful Paul Schmidt's patent GB741253 for a hybrid turbine / free piston / pulsejet device. It's hideously clever idea, if a little complex. Gas-operated valves, standard pulsejet valves, a compressor driven by 'spare' free piston energy, ignition timing triggered by the reciprocating motion of the engine itself, pressured fuel feed likewise. Mindboggling.

Simon
Attachments
GB741253.pdf
Schmidt hybrid pulse/piston/turbine engine patent
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Re: A few questions for the new pressure jet builder

Post by Bruno Ogorelec » Mon Sep 20, 2004 7:40 pm

tufty wrote:Gas-operated valves, standard pulsejet valves, a compressor driven by 'spare' free piston energy, ignition timing triggered by the reciprocating motion of the engine itself, pressured fuel feed likewise. Mindboggling.
Simon, mindboggling does not begin to describe it. I was gibbering after a while, trying to fathom the intricacies of this idea. Ohmigod. This man got bored with the simplicity of the pulsejet, made a 180-degree turn and stepped on the gas pedal.

And I thought I had feverish ideas...

Thank you for this. I haven't seen something in this class for a long while.

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Re: A few questions for the new pressure jet builder

Post by tufty » Mon Sep 20, 2004 8:11 pm

Check out his ram-pulse-detonation engine (patent DE968328). I think that's what it is, google translates the title ("Strahltriebwerk mit absatzweiser Verbrennung von Brennstoff in Luft durch Stosswellenzuendung") as "Jet engine with burn by paragraphs of fuel in air by shock wave ignition" and it looks like a hybrid ram/pulse engine. Less complex than the above. I only wish I could read German or had a decent OCR that I could then run through an online service ;-)

Simon

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Re: A few questions for the new pressure jet builder

Post by Anthony » Mon Sep 20, 2004 9:14 pm

tufty wrote:Check out his ram-pulse-detonation engine (patent DE968328). I think that's what it is, google translates the title ("Strahltriebwerk mit absatzweiser Verbrennung von Brennstoff in Luft durch Stosswellenzuendung") as "Jet engine with burn by paragraphs of fuel in air by shock wave ignition" and it looks like a hybrid ram/pulse engine. Less complex than the above. I only wish I could read German or had a decent OCR that I could then run through an online service ;-)

Simon
Those Germans always feel the need to put everything in the same word! Hehe.
Anthony
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Re: A few questions for the new pressure jet builder

Post by yipster » Mon Sep 20, 2004 9:59 pm

seen something in this class
nanosoft mentioned http://www.popsci.com/popsci/aviation/a ... -3,00.html devellopment on somehow similar hybrid engines. reading the printed Schmidt hybrid pulse/piston/turbine engine patent, mindbogling though

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Re: A few questions for the new pressure jet builder

Post by yipster » Sat Sep 25, 2004 2:09 pm

tufty wrote:
Bruno Ogorelec wrote:I can see some neat engines born out of wedlock to the turbojet and the free piston engine. your sketch is just the beginning.
Not a beginning, just one possibility. For example : attached is the ever-wonderful Paul Schmidt's patent GB741253 for a hybrid turbine / free piston / pulsejet device. It's hideously clever idea, if a little complex. Gas-operated valves, standard pulsejet valves, a compressor driven by 'spare' free piston energy, ignition timing triggered by the reciprocating motion of the engine itself, pressured fuel feed likewise. Mindboggling.

Simon
it took me a while to glue the text and draw arrows to the blown up Schmidt hybrid pulse/piston/turbine engine drawings and than to comprehend and like.

than i asked a pro engineer who pointed at "the good valve control system (the weak part on a PJ with automatic valve) the nice combustion chamber with automatic valves (only used at startup) it design to have a almost continous flow and lots of other features"

on the -no good- bear cam shaft oposed free piston http://www.dynacam.com/index.htm that mentioned high torque etc he replyd: "bull, and a grown up monkey reading their site should know better" that while i understood and liked that one instantly. guess i'm not much more than a interested iliterate here but wanted to let you know and say: yes tufty, that Paul Smidt is a genius, did this engine ever run?

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Re: A few questions for the new pressure jet builder

Post by Bruno Ogorelec » Sat Sep 25, 2004 4:34 pm

yipster wrote:wanted to let you know and say: yes tufty, that Paul Smidt is a genius, did this engine ever run?
Tufty, did this engine ever run?

As for the Dynacam, it's a nice concept, but does fall on the shaft drive. No one has ever made a really good swash-plate drive that I know of. It's been tried many times, primarily for Stirling engines, but it's inherently bad. Also, going 4-stroke on a free piston engine is not the brightest idea in the world. As if transferring linear motion into rotation were not bad enough, these guys also have to have a reduction drive for the valve gear, plus cam followers, pushrods, rockers, valves....

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Re: A few questions for the new pressure jet builder

Post by Viv » Sat Sep 25, 2004 7:38 pm

Bruno Ogorelec wrote:
yipster wrote:wanted to let you know and say: yes tufty, that Paul Smidt is a genius, did this engine ever run?
Tufty, did this engine ever run?

As for the Dynacam, it's a nice concept, but does fall on the shaft drive. No one has ever made a really good swash-plate drive that I know of. It's been tried many times, primarily for Stirling engines, but it's inherently bad. Also, going 4-stroke on a free piston engine is not the brightest idea in the world. As if transferring linear motion into rotation were not bad enough, these guys also have to have a reduction drive for the valve gear, plus cam followers, pushrods, rockers, valves....
Just to chip in a comment on the dynacam, my fathers "the oil engine manuel" from the fiftys has a 16 cylinder swashplate two stroke desiel in it that actuelly looks pretty much the same as their layout.

Viv
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Re: A few questions for the new pressure jet builder

Post by Mark » Mon Oct 25, 2004 2:26 am

Acetylene is a rather expensive fuel to be practical and besides there are jet engines that produce over 100,000 pounds of thrust using mainstream fuels. I suppose they could do it with acetylene but imagine the weight of a tank of such proportion, it's just not going to fly. My thoughts would be to maximize a new concept and don't focus on exotic fuels.
I've seen blends of nitro, methanol, and such, but again, if you have to pay 35 dollars a gallon for nitro, you kind of prefer gasoline. No sense in paying a lot for your carbon and hydrogen when for the most part they all put out "about" the same when combined with their preference of air. Mixed with pure oxygen any fuel can become a bomb or melt through just about any material if the engine isn't cooled. That's another problem, you want more heat/energy but then you need really expensive alloys. Look at a car engine, you'd get more horsepower if you could run hotter, but you don't see any models doing away with the radiator or other methods to keep the engine cool. So it's not just the fuel, it's also the materials science. For toying around, acetylene might be a lot of fun though, but do be careful, a cloud of acetylene confined could blast your eardrums permanently. And too, eye protection might be a good idea if your pulsejet is of a light-weight material.
Mark


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