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Mystery Target Drone engines?

Discussion in 'Gas Engines' started by stik, Jul 6, 2020.

   
  1. stik

    stik New to GSN!

    7
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    3
    Texas
    I picked up a couple mystery engines today, and was wondering if any of y'all can help with information on them. Very few markings on the engines, and my current theory is that they were target drone engines. I put a gallery up on Imgur https://imgur.com/gallery/KrkRpWX

    Very few markings on them. Mahle made the cylinders, but they make stuff for tons of companies.

    Thanks!

    -Pete

    [​IMG]
     
    WMcNabb likes this.
  2. While I've seen photos of these before, I have nothing of value to offer vice the provenance, sorry.

    Meanwhile, have you a clue regarding displacement? Is the carb mounted on the back of the engine? With known displacement, figuring out a suitable carburetor becomes easier (if you intend to run it). Value? Honestly, this is a squishy kind of thing, in my opinion. Why? It's because absent ignition and carb, box, packing, and manual, it's not considered original to collectors - but - based on my experience with engines that are sought after, e.g. Morton M-5, and others, we're still not talking sell-it-and-retire kind of money. More like pocket change for most folks.

    Anyway, it's certainly a nice conversation piece and there's every reason to believe you can make it run if it has compression. Noting the fact it's sand cast, I'd expect there are a fair number of them in the world. Last thing, while displacement can be calculated to a fair-thee-well with disassembly, merely sticking something through the exhaust port and getting an approximate diameter is going to get you in the ballpark in terms of selecting a carburetor because most 2-cycle engines are reasonably close to square (bore and stroke). Close enough, that is, for it to run and throttle reasonably well - just compare the cylinder diameter to available engines and easy peasy, you're there!

    Regarding the ignition, it's likely any two-cylinder module will work, e.g. something for a DLE, DA, etc. Especially as it looks like the pickup can be replaced easily enough and positioned for where whatever module you use wants it (in the vicinity of 20-25° BTDC usually). Is it alternate firing or simultaneous? This will matter.

    Craigslist? I've seen them pop up occasionally here (Orlando) but haven't been sufficiently motivated to obtain one. Anyway, it looks like fun . . . good find!
     
    stik likes this.
  3. stik

    stik New to GSN!

    7
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    Texas
    They're intrinsically valuable to me, because I love all kinds of odd engines! I've got a machine shop, so I should be able to make intake and exhaust eventually. Once a few of my other projects are finished. I'm building a model twin cylinder steam engine from castings right now.

    They've got great compression, and one of the engines looks new, while the one pictured above looks like it was installed at some point. Displacement is 65mm across the cylinder through the exhaust port. (430cc?) It's simultaneous firing it appears, or real close to it. It looks to me like the cylinders are made from a casting, with a liner I assume. The case and engine mount are forged Aluminum, and prop hub is machined from billet. Not sure what I'm going to do with them at this point, but I'm excited to have them! They're super cool

    Thanks for the information
     
    Last edited: Jul 7, 2020
    WMcNabb likes this.
  4. stik

    stik New to GSN!

    7
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    3
    Texas
    The rear of the engine looks like it runs the accessory drive, and intake ports are on the opposite side of the cylinder from the exhaust ports, much like the 2 stroke motorcycle engines I played with as a youth.

    [​IMG]
     
    WMcNabb likes this.
  5. I totally understand where you're coming from because I'm also queer for engines (meaning it would have a similar valuation to me). Anyway, with a 1:1 bore to stroke ratio, that's a pretty good size engine, ~200cc/cylinder, call it 400cc. Useful props would range around 36" diameter, maybe larger depending on the bore to stroke ratio, which could be as much as 1.6:1 plus how the engine is ported (RPM ranging from 3500-6000 would be a guess for a Vietnam era drone). Sounds like fun and when I retire from the servo business this would be the kind of thing I'd enjoy taking on for myself, also. Anyway, good luck and be sure to report back how things go.
     
    stik likes this.

  6. stik

    stik New to GSN!

    7
    4
    3
    Texas
    Last edited: Jul 7, 2020
    WMcNabb likes this.
  7. Very cool. Good job of sleuthing!
     
  8. WMcNabb

    WMcNabb 150cc

    1,619
    3,328
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    TN, USA
    stik likes this.
  9. WMcNabb

    WMcNabb 150cc

    1,619
    3,328
    113
    TN, USA
    One more interesting read from EAA’s Sport Aviation archive.
     

    Attached Files:

    stik likes this.

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