Pulsejet Restoration

Discussion in 'Aviation' started by GregP, Mar 7, 2013.

  1. GregP

    GregP Well-Known Member

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    #1 GregP, Mar 7, 2013
    Last edited: Mar 7, 2013
    Three of us restored a pulsejet from WWII and ran it at the 2009 Planes of Fame Airshow. We pushed my pickup down the runway on Saturday and down the taxiway on Sunday. You can hear it for 10+ miles because the frequency of the pulse is about 43 Hz and goes a LONG way! We made the front cowling that is shiny Aluminum and it was done by metal spinning. The paint discolored because the temp got to about !,250°F in the tube (we had telemetry).

    This should settle for all time whether or not the pulsejet could run while stationary. It CAN.


    View: https://www.youtube.com/watch?v=KTv7dfs_Mlc
     
  2. raumatibeach

    raumatibeach Banned

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    That's very cool , was your ute running the whole time on the jet?
     
  3. GregP

    GregP Well-Known Member

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    Don't understand the question ... please clarify ...
     
  4. T Bolt

    T Bolt Well-Known Member

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    That was so cool Greg! I've seen videos of guys with smaller home made pulse jets on bicycles but never a real one. I bet it was a blast to run it.
     
  5. GregP

    GregP Well-Known Member

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    #5 GregP, Mar 7, 2013
    Last edited: Mar 7, 2013
    Was. We have a WWII B-17 ball turret gunner (Wilbur Richardson) in our volunteers and he said he says he was in a London hospital when the first V-1 hit. When we got our pulsejet running (took a year because theghre was no manual), he came over and said, "I haven't heard that sound since London in WWII" He was very appreciative and we had him in the bed of the truck when we ran it down the runway. I'm in the left front corner of the truck bed and am the guy who started the pulsejet. The primary restorer, Robin Scott, was the guy who approached the pulsejet to get it into cruise mode power above idle. He KNOWS pulsejets!

    We can still run it, but the museum doesn't do that very often. Robin flies a Yak-52 and it is a very neat aircraft.
     
  6. raumatibeach

    raumatibeach Banned

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  7. GregP

    GregP Well-Known Member

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    We used the engine to get us to about 10 mph and let it go after that. We made it up to about 45 mph in about 1 minute. Combined weight (truck, trailer, and pulsejet) was 10,000 pounds! That's a HEAVY trailer and is all steel. When we hit 45 mph, my friend driving used the brakes to keep from going faster. We ran the pulsejet for 1 minute 15 seconds and the tube temperature got to 1,250°F. We didn't want to go any hotter because we only have two sets of valves and want them to be able to run for YEARS at the rate of once or twice a year.

    No sense in restoring a pulsejet only to burn it out, is there?
     
  8. Njaco

    Njaco The Pop-Tart Whisperer
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    That is cool as all hell!
     
  9. vikingBerserker

    vikingBerserker Well-Known Member

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    That's just fricken awesome Greg!
     
  10. GregP

    GregP Well-Known Member

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    #10 GregP, Mar 7, 2013
    Last edited: Mar 7, 2013
  11. Gixxerman

    Gixxerman Member

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    #11 Gixxerman, Mar 7, 2013
    Last edited: Mar 7, 2013
    Very cool stuff Greg.
    I bet it sent a chill up Wilbur Richardson's spine thank God for the 60+yrs on!

    Here's a question.....the flame out the back, is this ideal or just a function of this kind of engine?
    Most, if not all, jets running normally (except those with afterburning, of course) don't do it.
    But every V1 I've heard of had it.
    I know engine manufacturers 'tune' jets and I know the pulse jet is something different altogether but I mean
    does it signify a less efficient burn or is it just the nature of the beast?
     
  12. GregP

    GregP Well-Known Member

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    #12 GregP, Mar 7, 2013
    Last edited: Mar 7, 2013
    The flame out the back is normal for a pulsejet that runs on gasoline. Most jet engines have a combustion chamber and the fuel gets burned in it, and only the hot gasses emerge from the back end of the jet. If you see flames from a turbojet or turbofan, they're usually from the afterburner (reheat) since flames from the jet would damage the jet turbine baldes due to excessive heat. The only reason other than efficency I can think of for no flames through a jet is turbine blade dmage. Otherwise, nobody would care.

    In a pulsejet, the tube itself is the combustion chamber and the fuel is incompletely burned when it leaves the tube, so it's still "on fire," or still burning. I have a great video we shot a night showing the glowing tube and lots of flames, but I can seemingly only post stuff from the web ... I can't see how to upload it from my PC like I can a picture file. When it is dark, the amount of heat you can see is amazing. The whole tube glows red. Flames tend to be hard to see in daylight.

    We timed the combustion cycle at 43 Hz, so its is a low-frequency thing that can be heard for miles ... about 10 miles to be more precise. The first time we ran it, a fire truck from 5 miles away came over to see what exploded! We ran it again for them and they left happy.
     
  13. Ascent

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    There was an episode of Scrapheap Challenge in 2003 where teams had to build a jet powered car. One used the turbo from an articulated truck and the others built a pulse jet totally from scratch as far as I can recall. It worked quite well as far as I can recall.
     
  14. Gixxerman

    Gixxerman Member

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    I hope you can get your vid sorted Greg I'd love to see it.
    I've heard of this but not seen it, I imagine it looks pretty impressive stuff.

    (I remember reading years ago that SR71's cruising at mach 3 and a bit or thereabouts glowed cherry red, that's
    another sight I'd love to see but I've never seen a pic of it)

    @ Ascent

    I think I saw that one - the water jet car the pulsejet/afterburning one?
    Brilliant show...... but you can't help thinking 'thank God it hasn't gone wrong' for those guys, they really
    are building from a scrap heap guesstimating on the hop.
     
  15. Gnomey

    Gnomey World Travelling Doctor
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    Very cool!
     
  16. GregP

    GregP Well-Known Member

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    #16 GregP, Mar 7, 2013
    Last edited: Mar 7, 2013
  17. GregP

    GregP Well-Known Member

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  18. gjs238

    gjs238 Well-Known Member

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    Have you considered mounting the pulsejet on that boat?
     
  19. GregP

    GregP Well-Known Member

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    No because the boat has a blown 501 Chevy in it and tops out at about 76 mph.

    We think the pulsejet would be slower.

    The aircraft behind the trailer is a Yak-52.
     
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