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Thread: Ultralight engine options

  1. #1

    Ultralight engine options

    I'm Trying to build up a 103 legal single seat challenger and this will require a single cylinder engine. 277 rotax is one choice. Has anyone been powering their plane with an engine from a powered paraglider? (compact radial MZ34?)

  2. #2
    Dana's Avatar
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    I believe quite a few people have used these engines for ultralights. Actually 30HP is on the large side for a PPG unless you're a big guy of flying tandem.

    Gonna vibrate more than a 2 cylinder engine, though.

    There are other engines in that range, including the 28HP Hirth F33 and the new 35HP Aerocorsair Black Buill.

    Dana

  3. #3
    is the 277 still in production in Europe? I see there are still some spare parts available for them. I would rather not use a belt reduction so this is the route I will probably have to go.

  4. #4
    Jim Heffelfinger's Avatar
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    Here is info on the Polini engine. Belite had a bulk buy going for $ 4495
    https://jameswiebe.wordpress.com/201...e-ever-except/

    You can still find all the Rotax engines here in the US. May not be new but rebuilt. Also consider the Kawasaki 440 series.
    Belt reduction ( modern belts) are as reliable and much lighter than a gear box.

    Getting weight down is based on constant vigilance. Every part scrutinized for weight v utility. Surprisingly paint often seals the deal overweight. Consider 2 coats of exterior acrylic paint. Polyfiber, and others, can push paint weight 15#. Consider light fabric (finer weave) fills faster.
    best of success.
    Jim
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    Chapter 52
    Last edited by Jim Heffelfinger; 12-20-2015 at 02:52 PM.

  5. #5

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    Quote Originally Posted by aeroschmitz View Post
    is the 277 still in production in Europe? I see there are still some spare parts available for them. I would rather not use a belt reduction so this is the route I will probably have to go.
    The 277 is still made, or was being made a few years ago. I understand that Rotax won't sell them individually but you can by them in lots of 25 or maybe 50. Steve Beatty (Airscrew Performance is his company name) still had some brand new ones a few years back. I'm not recommending him, just saying that he's a possible source for a new 277 engine. The gearbox is another story. I don't think Rotax has made an "A" model gearbox since the late 80's and they are getting scarce. You can still buy the internal parts and rebuild them, but it's costly.

    I think the best engine currently available in the HP and weight range of the 277 is the Polini Thor 250. It's pricey, but it's a thing of beauty. Here's a page with a lot of info on it:

    http://emg-6.blogspot.com/search?q=polini

    The one weak point on the Polini is the gearbox. It's designed for the short light weight props on paragliders. It won't handle the inertia of a longer, heavier prop. You'll need to go with a wooden prop if you want to stay within the specs for the Polini gearbox. The Rotax 277 vibrates something fierce. It was tearing up my airframe. The Polini is smooth as silk, due to a combination of the counter rotating balance shaft and the clutch that disengages the prop at idle. Even with electric start, the Polini is lighter than the 277. It's pricey, though. North of $4500.

    The Hirth F33 is another good option. What I've seen with Hirth is that you have to be a good enough mechanic to set up the carburetor and make it run. They seem to often ship the engines with the wrong jets in the carbs an both of the pilots I know who've bought new Hirth engines have had to spend several hours and a few $$ buying and trying carb jets to make them run right. Once they are set up right, they seem to be good running engines. The F33 is considerably lighter than the 277 and also has a really slick optional electric start setup.

    I used to be adverse to belt drives as well, based on my experience with them back in the 1980's. I've recently started running a MicroV belt reduction drive on a Kawasaki 440 and I couldn't be happier with it. After tightening it twice during initial break-in, it's required zero maintenance for nearly 100 hours. It's lower maintenance than a Rotax gearbox, which requires oil changes and spring washer replacements. I wouldn't trade that MicroV drive for a gearbox even if one was available for the Kawasaki.

  6. #6
    Yup, those 12 spring washers are suppose to be replaced at 150 hours in the A box

  7. #7
    Any twin is too heavy at this point for the project. To bad there is no honest weight information on out of production motors like the Kawasaki.
    Jim, what belt redrive are you running?

  8. #8
    Jim, what redrive are your running?

  9. #9

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    Quote Originally Posted by aeroschmitz View Post
    To bad there is no honest weight information on out of production motors like the Kawasaki.
    My fan cooled Kawasaki 440 with exhaust, electric start, and what J-bird calls the "up-up" version of the Micro V redrive weighs 83 pounds. That's without the pull start and carburetor mounted. The exhaust is the style that turns upward and mounts on brackets attached to the cylinder head of the engine, similar to the common Rotax exhaust setup. It makes a nice compact package. Compared to the old 277, this thing felt smooth as a turbine engine. I'm very happy with this Kawasaki power package. Name:  IMG_0477.jpg
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  10. #10
    Jim Heffelfinger's Avatar
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    Have you looked at J-Bird catalog ? They have new Kawasaki engines in addition to many others including the Rotax. http://j-birdengines.com/ One of the quirks of the marketing is that you need to be aware that some of the prices are for engine cores only - starter, carb, reduction etc are to be added on.
    I have a Kow 440 B core available. I am using a MZ201 in my Koala with belt reduction of 2:1. It, like all the other small Fishers, ( FP-series) will not make weight and I am going E-AB.
    Hope this helps.
    Question: is your plane a Challenger 1 or a 2 with the back seat removed? Is it already built ?
    If you go with a Bing Carb take the time to watch the EAA hints for home builders video on the Bing carb ( several in a set) by Brian Carpenter. Bings are a bit of chore to set up correctly but once done they work fine.

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