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Ukraine updates the Doodlebug
Feb 23, 2025
Last reply: 1 year ago
9 Replies
Do they not use reed valves?
It is not necessary if you use a folded tube and a resonant cavity.
Efficient they aint and the noise is horrendous. But it works
Yes, I've seen the U shaped ones, but that doesn't look like what's shown, just a straight tube?
The noise adds to the fear-factor.
There is a kind of valveless pulse jets.
Most valveless pulse jets have the intake pointing in the reverse direction, as per the photo in the above article, due to the exit of gases through the inlet during the 'pulse'.
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For general interest in a real machine:
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Look again. There is no frontal air intake, juts a couple of rearward facing ones
I never find fear factor a useful metric for anything....
Some form of ramjet perhaps?
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They need to be accelerated to a certain speed by boosters such as solid-state rockets before the ramjet comes into action.
It depends on the design of the ram jet or pulse but even the single straight tube variety can be started with something as simple as a leaf blower.
This video suggests that forward motion just increases efficiency of a pulse jet, they can run without forward motion.
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Jam jar pulse jet plus 3D printed (metal)
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There may be a need for some form of catapult or booster rocket to initially get them airborne but these seem to be much smaller and a lot lighter than those used during WWII and would require the kind of infrastructure that the Germans had to use to launch them.
Apparently what happened was it went into the dive and the jet sucked air. Because of the dive angle..
Oh yes. Ive heard model pulse jets. Across the whole bloody airfield.
If you drive past Duxford there is a V1 launch ramp by the fence
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It's not concrete.
Andy
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