www.pulse-jets.com

Nick wrote:

Ben wrote:What did types 02 through 06 look like?

They lived only on the drawing board or in U Flow, unless the original FWE i did was an 06 but i dont think so, Graham ?

Nick

There never was a Type02 to Type 06, at least not in my drawings. I think Mikes going to explain this one. This motor was designed to test a set of governing principals nothing else.

Graham.

The "07" is just a duct style which features a double restriction based on one of the Messerschmidt drawings. Graham's work though is toward the governing principles he mentions, and also how those principles are optimized in UFLOW, since we have no better software available. The Messerschmidt drawing pointed to some interesting wave reinforcement. It's been my priveledge to track his progress in this, and contribute where I can.

This engine being able to run with such a high tail expansion at this short a length is quite a trick indeed! I hope it proves to be a strong contender.

Mike Everman wrote: It's been my priveledge to track his progress in this, and contribute where I can.
der.

Yes, Big thanks to Mike for all the feedback.

Graham.

This sketch of a Marconnet struck me as being short for a valveless. Interesting how the valveless pulsejet and ramjet have this gray, vaguely defined separation. And in Foa's book, to reiterate, he says the line of demarcation is blurred when analyzing a sub-sonic ramjet in which combustion benefits from pulsating combustion.
I guess though short valveless designs have been on helicopter blade tips for some time, optimized to run at speed and utilizing ram air. There is that trade-off if you want or need a certain thrust when stationary. Imagine all the degrees of separation there are in that spectrum.
I posted this sketch because a subtopic was how Nick's jet was somewhat shorter than the classic designs, (in case you think I drifted off topic again). ; )
Mark

Yet in Lockwood's literature, they have the Marconnet being much longer. I wonder if someone could find out all the shapes Marconnet toyed with? And what was he like, are there any photographs of him drinking absinthe or something? I think it would be interesting to know more about some of these inventors, might as well have a better understanding of the history, and how the ideas came about. I wonder if his neighbors were some of the first to exclaim, "What the hell is that noise!" (in French of course).
Mark

im quite looking forward to firing back up again having had a bit of a mull over things for a day or two, one thing hich occurs to me is and i could really dod with some feed back here.
I fired it up at a throttle setting that i arrived at by slowly increasing the throttle untill it fired and self sustained, as you all saw the test was brief. Would i be correct in assuming that this setting was perhaps the minimum throttle setting? if so then perhaps it has much more thrust in store for us one that throttle is opened more?.

Nick

Wow, nice one Nick.

I particularily like the HAZ moving out towards the ends in the first video. I'd like to see that vid in higher res actually.

Cheers,

Wilson.

Nick wrote:im quite looking forward to firing back up again having had a bit of a mull over things for a day or two, one thing hich occurs to me is and i could really dod with some feed back here.
I fired it up at a throttle setting that i arrived at by slowly increasing the throttle untill it fired and self sustained, as you all saw the test was brief. Would i be correct in assuming that this setting was perhaps the minimum throttle setting? if so then perhaps it has much more thrust in store for us one that throttle is opened more?.

Nick

I think the answer is "not necissarily". I've had them catch on high and low.
When mine is on the test stand, though. It's helpful to block or clamp it from moving so catching doesn't change the position of your start air.

evildrome wrote:Wow, nice one Nick.

I particularily like the HAZ moving out towards the ends in the first video. I'd like to see that vid in higher res actually.

Cheers,

Wilson.

Dear Wilson.
What is the HAZ ?

Graham.

Mark wrote:This sketch of a Marconnet struck me as being short for a valveless. Interesting how the valveless pulsejet and ramjet have this gray, vaguely defined separation. And in Foa's book, to reiterate, he says the line of demarcation is blurred when analyzing a sub-sonic ramjet in which combustion benefits from pulsating combustion.
I guess though short valveless designs have been on helicopter blade tips for some time, optimized to run at speed and utilizing ram air. There is that trade-off if you want or need a certain thrust when stationary. Imagine all the degrees of separation there are in that spectrum.
I posted this sketch because a subtopic was how Nick's jet was somewhat shorter than the classic designs, (in case you think I drifted off topic again). ; )
Mark

Dear Mark.

You hit the nail on the head. Forward motion or forced induction air moves the massflow balance point of the motor towards the rear and performance drops for a number of reasons. Designs like these attempt to address this problem. The strange sub wave structure of the design allows you to take liberties with the conical half angles. The one design allows you to play with at least 3 modes of operation just by changing the proportions, so I would not be surprised if the early French designers had many long and short variants of the design.

Graham.

Graham C. Williams wrote:

Mark wrote:This sketch of a Marconnet struck me as being short for a valveless. Interesting how the valveless pulsejet and ramjet have this gray, vaguely defined separation. And in Foa's book, to reiterate, he says the line of demarcation is blurred when analyzing a sub-sonic ramjet in which combustion benefits from pulsating combustion.
I guess though short valveless designs have been on helicopter blade tips for some time, optimized to run at speed and utilizing ram air. There is that trade-off if you want or need a certain thrust when stationary. Imagine all the degrees of separation there are in that spectrum.
I posted this sketch because a subtopic was how Nick's jet was somewhat shorter than the classic designs, (in case you think I drifted off topic again). ; )
Mark

Dear Mark.

You hit the nail on the head. Forward motion or forced induction air moves the massflow balance point of the motor towards the rear and performance drops for a number of reasons. Designs like these attempt to address this problem. The strange sub wave structure of the design allows you to take liberties with the conical half angles. The one design allows you to play with at least 3 modes of operation just by changing the proportions, so I would not be surprised if the early French designers had many long and short variants of the design.

Graham.

Mark and Graham -

Good one! This is something often missed in talking about the exact angles of cones and "sharpness" of transitions. Without variable geometry, it is probably impossible to design an engine that is BOTH optimal for static running AND optimal at some practical forward speed. The ramjet is just a carrying of this idea forward to the ultimate extreme, really - it won't even function below a certain forward velocity but is highly efficient at some point well above the speed where it starts working.

This should not seem strange. For about a century now, engineers have been designing gas turbine combustor nozzles and turbine buckets ["vanes"] to have a satisfactory angle and curvature for optimal efficiency at speed, not stationary (as they are at startup). The difference is large, not subtle, because the relative speed between the nozzle and the turbine buckets is such a high value when the engine gets up to speed. Even the design of the stationary vanes is affected by the working rotational speed.

This is another example of why it's futile to try to measure some "maximum" static thrust as a comparison between engines [unless the only purpose of both engines is static running]. You have to be able to measure what the engines will do at some reasonable speed. The ultimate goal of most engines, after all, is to get something moving.

L Cottrill

evildrome wrote:Wow, nice one Nick.

I particularily like the HAZ moving out towards the ends in the first video. I'd like to see that vid in higher res actually.

Cheers,

Wilson.

I can send you the original avi if you want it?

Nick

Great stuff Nick, and Graham too of course.
Youve been around for quite a while attemting to make engines that arent run of the mill. Im totally thrilled to see you have got that little baby running.
Im sure Graham has put a lot of effort into modelling on U-flow and its good to see results like that.

Keep up the good work lads, you both try and try and try. Lets now see the results get better and better and better.

Cheers,
Gary

GARY ME OLD MATE!, where have you been buddy?. what have you been doing? great to have you back by the way. email me an update!.

Cheers

Nick

Good to hear from you Gary.
I'm glad things are working out for you. You've been missed.
Thanks for the good words about the motor. This little motor is just the start; it's a bit soft compared to the two in development.

Don't wait too long for your next visit to these pages.
Regards
Graham.