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Thread: Need advice on ultralight build

  1. #11
    I have been into gokarts quite a bit, and have reliable engines that Could strip down to bare minimum, and have it weigh 28-30 lbs. pushing 20hp


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  2. #12
    Sam Buchanan's Avatar
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    Quote Originally Posted by TheBigSoulwinner View Post
    I have been into gokarts quite a bit, and have reliable engines that Could strip down to bare minimum, and have it weigh 28-30 lbs. pushing 20hp


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    You are asking questions that have complex answers but one factor to consider is optimizing prop tip speed. This requires an engine with a gearbox unless very small-diameter props are used which are not suitable for anything but the tiniest ultralights. The single-cylinder engines sometimes in use for ULs are the in 30-35 hp range and are geared to allow the prop to remain in a useful RPM range.

    Here is one example:

    https://www.polinithor.com/en/polini...thor-250-ds-2/

    There are used engines out there that have been out of production for several years......if you care to roll the dice....
    Last edited by Sam Buchanan; 03-06-2020 at 11:00 PM.
    Sam Buchanan
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  3. #13

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    Quote Originally Posted by Sam Buchanan View Post
    Google doesn't know much about the fine points of Part 103.

    The AffordaPlane ends up being much too heavy to qualify for 103. See my post above yours for a legal option.
    Thanks for the heads-up and good info - Truly appreciated. I've a lot to learn about these here airplanes.
    "Don't believe everything you see or read on the internet" - Abraham Lincoln

  4. #14
    Same here!


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  5. #15

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    "a lot of research into old non-copywrite plans" --- That's a very dicey area. If you and your friend have no aeronautical design experience, building from old UL plans that weren't worth copywriting is signing up to repeat fatal mistakes from the early UL days. And if you're going to design your own, you will need to do a lot of reading about weight & balance, metallurgy, prop tip speeds/gear reduction, structure design, etc.
    And as others have said here, under $2000 is not real. Find a banged-up ultralight that was a good design and rebuild it. You could find one without engine in that money range. Read up on fabric strength testing on old fabric.

  6. #16
    Thanks, I see what you all are saying.
    I guess that is why I asked.


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  7. #17
    The Bloop Motorfloater would make Orville and Wilber proud. It's a lightweight, build at home with hand tools kind of machine but a fair weather flyer, not intended to handle gusty winds. Plans for the Bloop are free to download and quite well documented. This is about as basic as you can get and as low cost as possible. Forget the go-cart motor. You want something that is designed from the ground up as an aviation engine/prop combo. The Bloop uses a engine/prop combo borrowed from a powered parachute. It will be your biggest expense. If you build one be sure to get some time flying in a two-seater like a Quad Cities Challenger before climbing into a single seater. Good luck. Arriving at any destination starts with the first step.
    http://m-sandlin.info/bloop/bloop.htm
    Last edited by Ronald Franck; 03-14-2020 at 07:36 AM. Reason: Added information

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