Pulsejet Powered Ramjet Engine

[larry cottrill]

Al -

What wonderful information! Please duplicate this post on the Ramjets Forum for reference there.

L Cottrill

[Jim Berquist]

More Great Stuff from You Eric:

Same set up I am looking for on the little Beast that You built for me!

I am trying a inverted rolled intake, as I think it may mix Better. Expert not: Experimenter Yes.......My Idea is that the turbulence of intake will mix the fuel better and compression will still be present.....I originally tried a donut type flame holder. I am changing it to a grid of holes like the stopper set up.

Anyone out there have any Idea's for me?????

Jim

[AP mechanic]

Hello everyone

I am an AP mechanic and have always been interested in aircraft and powerplant systems. I am new and don't understand a lot of what I have read on this site. I have visited this site almost every day for a year or so in hopes of learning something. I have a question for you Eric. What did you see or what observations did you note that caused you to change the dimensions of the first ramjet powered by the pulsejet. Also have you created the new nozzle yet and will we see the run with a new nozzle.

Thanks

[Eric]

Well the original system limited the flow of air way too much, a change to the design now lets the pulse dampening be proportional to the pulse power, and provides more air flow on low power so it can burn lean on any throttle setting.

Eric

[AP mechanic]

Thanks for the reply... what specifically did you observe that indicated restricted flow? Was it just an observation that the PJ was more flow than was being utilized. How did you theorize that the [u]CC needed to be shortened while increasing diameter[/u] ( I realy want to know that...hence the underline) . I am sorry if I am not asking the questions correctly, I have been accused of this before. I am just trying to understand the thought process that went into your changes and the observations that lead you in that direction. I am only asking, because as stated earlier I dont understand a lot of what I have been reading and I am very literal.

Thanks again

[Eric]

Well had a very fun run tonight. Got the engine to make a hell of a blast, caused me to jump a bit and turn off the fuel. Also if you play back the video frame by frame you can see how much recoil the blast had....

I didnt even notice until I played the video back on the computer, it all happend so fast, but the massive 20" diameter mushroom cloud fireball shot from the back of the engine flash vaporized the snow on the ground and turned it into a puff of steam that got blown away by the shock wave.

Also I took a funny pick of the lack of snow for around 100' behind the engine :)

Eric

[Zippiot]

I have seen people use valvless pj's to de-ice icy/snowy roads, I think you invented an afterburner for that set-up!
Mount it facing down on the back of a vehicle and sell your time to the city!

[heada]

Eric,

Looking at the size/shape of the ramjet, it looks to me that it closely matches the size/shape of the ramjet from the paper Decker wrote. Is that the case? If so, do you know the air speed of the pulse-jet is putting out? The net thrust of the pulse-jet alone would be interesting as well.

I'm wondering how effective the ramjet design is (assuming it actually is the design Decker wrote up). He assumed 3.5 pounds of thrust per square inch of diffuser entrance area at 800 fps. In his paper, he designed for 10 square inches giving 35 pounds of thrust. I'm curious if you're seeing that amount of thrust from the ramjet (if the airspeed is similar).

I'm still amazed by the setup you've got there.

-Aaron

[Jim Berquist]

Back when I was dumber then I am now! Hard to believe haa!!!!

I worked with Allied Aircraft in Tucson. We sold a bunch of General Electric jet engines off some moth balled S2-p2v planes to South Pacific. They placed them on the lead locomotive at a 15 degree angle and used them for snow blowers, deicers on the track.......The engines they received were time lifed....They could not be rebuilt but was rated for another 80% for the next 200 hours. They would run them at 15% for a few years and call it good....I pulled 20 of them off of the planes, I think they may have delivered about half of that!!!!

Eric: how come the video didn't show the Ram Running?

Still working on the little beast thing! With the wind chill , it been like 17-20 degrees around here and the bottle says, PISS ON YOU!!!!

Jim

[Mark]

A nice short blasting rev of combustion Eric.
Mark

[Mike Everman]

That's just good clean fun, man.

[Jim Berquist]

Eric: Man , that thing looked like it sent out a formidable shock wave on ignition!!!!!


Jim

[Eric]

Heres a fun clip of the pulsejet igniting the ramjet and me throttling it up and down real quick on liquid propane. Love how the inside glows whiteish blue and then huge flames shoot out :D

I will probably post the full high quality version on youtube sometime in the next few days.

Eric

[Zippiot]

ERIC OMG!!!

You see how much more the camera shakes when the ramjet is lit?

I wanna build one of these but gonna change it up, gonna use the exhaust as the airpusher for the ramjet and have the valvless bent so that the exhaust doesnt stick way out past the intake, just to keep things compact...

[Eric]

Yea i have a clip of me throttling the engine from high to low over and over, on high the camera shakes like crazy, on low it doesnt, pretty cool.

Im already developing one for the pulsejet exhaust. Thats going to be a hard thing to do making the exhaust shorter than the intake unless its a straight piper.

Eric