steve's TLAR ramjet

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Bruno Ogorelec
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Re: re: steve's TLAR ramjet

Post by Bruno Ogorelec » Thu May 19, 2005 7:37 pm

Going for the complexity of the motorjet somehow doesn't look like the wisest choice to me, given that you can have a turbojet for the same amount of trouble.

A turbojet responds well to afterburning. It can also be made to transition to ramjet very nicely. So much better than a motorjet in my opinion, lighter, more fuel-efficient, less bulky...

In other words, the proper places for the motorjet -- in my personal, possibly biased opinion -- are two: (1) history and (2) Junkyard Wars.

steve
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Re: re: steve's TLAR ramjet

Post by steve » Thu May 19, 2005 8:45 pm

Larry Cottrill wrote:Steve -

An important question I should have asked already, since it bears on the testing of Maggie Muggs:

Obviously, the way you have your air supply located and positioned, you're getting a lot of air flowing around your engine as well as through it. Did you see any indication of red hot metal anywhere? It certainly doesn't show in the pictures and video.

Any comments you'd like to make about heating of your engine would be interesting, I think.

L Cottrill
Since you used glue to put maggie together, My advice to you is to keep the air source running for awhile even after the engine has been shut down. Otherwise the extremely hot tailpipe will transfer heat to the foward parts of the engine. It takes this engine as much time to cool down as it does for my pulsejets! since this engine dosn't "breathe" like a pulsejet (which cools it from the inside), If it didn't have cool air flowing around it I am convinced that it would melt within a minute.

In other words, the proper places for the motorjet -- in my personal, possibly biased opinion -- are two: (1) history and (2) Junkyard Wars.
well put Bruno!
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larry cottrill
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re: steve's TLAR ramjet

Post by larry cottrill » Thu May 19, 2005 9:01 pm

steve wrote:Since you used glue to put maggie together, My advice to you is to keep the air source running for awhile even after the engine has been shut down. Otherwise the extremely hot tailpipe will transfer heat to the foward parts of the engine. It takes this engine as much time to cool down as it does for my pulsejets! since this engine dosn't "breathe" like a pulsejet (which cools it from the inside), If it didn't have cool air flowing around it I am convinced that it would melt within a minute.
Yes, I already had that in mind - lots of air after the run! I'm surprised at your observation of long cooling time; of course, SS is notorious for holding onto heat. What's the thickness of your material?

L Cottrill

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re: steve's TLAR ramjet

Post by steve » Thu May 19, 2005 9:11 pm

.035 inch mild steel
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re: steve's TLAR ramjet

Post by mk » Thu May 19, 2005 9:22 pm

Hey Steve!

Another impressive piece of work! Congratulations!

What do you think of drawing up a kind of plan?
So everybody who wants could easily build a "Steve Ramjet" for himself.
mk

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re: steve's TLAR ramjet

Post by larry cottrill » Thu May 19, 2005 10:23 pm

What's interesting in the photos is the eight-lobed pattern of discoloration. It is much less 'lobed' than I would have expected, perhaps indicating that the domed asterisk works really very well, though seemingly crude at first glance. Very impressive operation, all around. You know, it almost couldn't BE any simpler than that!

L Cottrill

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Re: re: steve's TLAR ramjet

Post by steve » Thu May 19, 2005 10:37 pm

mk wrote:Hey Steve!

Another impressive piece of work! Congratulations!

What do you think of drawing up a kind of plan?
So everybody who wants could easily build a "Steve Ramjet" for himself.
As requested:
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re: steve's TLAR ramjet

Post by mk » Thu May 19, 2005 10:51 pm

That rules!
Thanks very much, Steve!

The flameholde IS amazingly crude AND well working, at least as it seems to me.

Maybe folding the fins a little radially in the middle of each stripe might bring some further improvements?
mk

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re: steve's TLAR ramjet

Post by steve » Sat May 21, 2005 2:44 am

I'm not so sure, If that was the case I would think that hiller would have used that potential improvement on their ramjet. the fact that they stuck with flat "fingers" on their flameholder suggests that maybe this layout produces the greatest amount of turbulence and therefore the best mixing of the fuel and air.

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Based on the performance data of some similar engines (see the stuff mark posted in the Maggie muggs clone thread) I believe that an 8 ft radius test rotor spinning at 350-400 mph will be perfect for this engine.
As of right now I am very seriously considering building such a rotor using 1/2 EMT streamlined with thin aluminium sheets. I have figured out a way to fuel it with propane while it is spinning, and the only thing that I am still unsure about is how I will balance the rotor (placement of counterweight etc.) and how the bearings will be put together with as little machining as possible.

any suggestions would be appreciated.

I would also like to conduct rotor tests of the various small pulsejets that I have built (my FWE's) to see how they perform at high speeds.
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Re: re: steve's TLAR ramjet

Post by resosys » Sat May 21, 2005 2:59 am

steve wrote:any suggestions would be appreciated.
I'd recommend using an automobile axle and bearings and connecting your rotor to the brake drum/disk. I'd also recommend having a cable hooked up to the brake so you can stop things fast if necessary.

Many of the spinning fire art projects I've worked with for the Burning Man festival have used this method. They're cheap and easy to find and shouldn't fail in such a light application. Front spindles seem to be the easiest to manage. A Honda or Acura setup pops off with basic tools if you have a pick and pull type auto junkyard in your area. Getting the brakes to work might be a bit of a chore with a disk. Even having a spring loaded bar that rubs the disk when you want the thing to stop should be sufficient.


Chris

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Re: re: steve's TLAR ramjet

Post by hinote » Sat May 21, 2005 3:21 am

resosys wrote: I'd recommend using an automobile axle and bearings and connecting your rotor to the brake drum/disk. I'd also recommend having a cable hooked up to the brake so you can stop things fast if necessary.
Chris--this seems quite a good idea.

I've been contemplating a method of testing my engines at high forward airspeeds, and this seems to be a relatively simple way to accomplish the job.

One of the most interesting problems would be limiting the max rpm the assembly is capable of. A simple flat plate to increase the drag and limit the rotational velocity to desired levels would seem appropriate. Start with a big plate, then measure the rpm and cut some off if necessary. Re-measure, etc, etc.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

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re: steve

Post by MANOLO » Fri Jun 03, 2005 12:25 am

hello steve, I am called alive Manolo in Spain,
I have some questions that hacerte.
I and constructed a turbine,
I want to make your ramjet.
it tell me as it is the injector, or pon photos porfabor.


thanks.....
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steve
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re: steve's TLAR ramjet

Post by steve » Fri Jun 03, 2005 2:18 am

the injector is just a piece of steel tubing mounted 3cm behind the flameholder with the injector hole pointing foward (towards the flameholder) the hole is 1/4 inch dia
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re: steve's TLAR ramjet

Post by MANOLO » Sat Jun 04, 2005 9:44 am

hello steve.
queria knowledge that air to pressure you use?
that maquina she is the one that produces the air?

I already have ramjet I throw injector lack.

thanks
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re: steve's TLAR ramjet

Post by steve » Sun Jun 05, 2005 4:36 pm

The air is provided by a leaf blower running at full throttle.

your air supply can be anything as ling as it will generate a large volume of high velocity air. The higher the velocity the better. (subsonic ramjets work best around 400 mph)
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