Very cool engine

Ed Huntress · 2009-08-12T17:50:43+00:00

Maybe everyone knows about this engine but me, but if not, this is a very cool little piece of machinery worth looking into. It's the rotary-valve 4-stroke used in the Honeywell hovering drone that's being prepared for field use by the US Army:'s built by a British company, RCV Engines Ltd., and it's amazingly simple. They've made available a 7-year-old SAE paper about it, with lots of detail about the seals (for anyone who's followed rotary-valve engines over the years, that's where most of the action is): must be pretty darned reliable to be used in the drone, so this is more than just another weird engine curiosity.Here's RCV's home page. They make model engines, too:Ed Huntress

Aug 12, 2009 29 Replies

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Ed Huntress 17 years ago

Yeah, I had several Jetexes. The actually were rockets, with come kind of oxidizer in the fuel pellets. They were heavy little suckers but they were reliable. I made a balsa glider powered with one and it burned up spectacularly at about 100 feet of altitutde.

I also used one on a little three-runner sled I made when I was about 11, which I ran on the pond next to my house. It was fast. My buddy lashed an Estes model rocket onto it and drove it through the side of his garage. d8-)

I've been hearing about these miniature turbojets and they sound like amazing pieces of work.

-- Ed Huntress

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cavelamb 17 years ago

If you ever get a chance to see one run, take ear plugs AND muffs.

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RBnDFW 17 years ago

Or the 16-cylinder 1.5-liter W BRM

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Ed Huntress 17 years ago

Yeah, if they have a rotary-valve solution that seals tight, that's not too expensive, and that really lasts, it could be a very big deal.

-- Ed Huntress

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Steve Lusardi 17 years ago

Ed, I am a gearhead and I never heard of this either, but I spent some time in studying this in detail and it is amazing and yet simple, although the seal IS seriously high tech. The seal screams for a ceramic solution and they are keeping that solution in reserve. I think this holds incredible potential in performance, fuel efficiency and cost. I think you will see these next in outboard motors. Multi-cylinder variations are some ways down the road, but I see those problems being addressed in the future economically as well. Steve

little piece of machinery worth looking into.

being prepared for field use by the US Army:

They've made available a 7-year-old SAE paper

rotary-valve engines over the years, that's where most

than just another weird engine curiosity.

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axolotl 17 years ago

One of the fellows at work saw the UAV in question this morning. It's a screamer. The characterization was gargantuan leaf blower.

Kevin Gallimore

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Gerald Miller 17 years ago

At a tractor show in Caledonia, ON. some years ago, a guy had a radial diesel tank engine - impressive. At the same show, someone had an X-8 flat head, water cooled aircraft engine supposedly an experimental Ford product. It was mostly a rusty lump of cast iron, nowhere near having any moving parts; I have never found any further information on this particular engine. Gerry :-)} London, Canada

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Ed Huntress 17 years ago

Was that the Caterpillar corncob engine from WWII? My father-in-law worked on that. It was a great engine, but it had so much torque that it kept twisting off the transmission input shafts, so it wasn't used.

-- Ed Huntress

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