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Thread: Full Lotus and HKS power??

  1. #1

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    Default Full Lotus and HKS power??

    It took me way longer than expected but I have installed an HKS 700e on my Model 3. I have not flown it since changing to a my new Kiev propeller a couple months ago, but I was very happy with the performance I got from the IVO that I took off and only expect it to get better. So now I have a friend looking to offload a pair of 1220s he got with a trike and I am strongly considering buying them. Can I get a few best guesses as to whether it would be powerful enough with the HKS, 3.47 gearbox, and 67" Kiev? I am fairly certain it would work as a single seat plane if nothing else, but I would like to take the family with me. I'm not sure I want to invest the time and money if its sure to be a one seat plane and I can't find any precedence for an HKS plane on Lotus floats.

    Thanks!

  2. #2
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    Default Re: Full Lotus and HKS power??

    From what I've read, and talked to one guy with a Kitfox 3 with the HKS, you will be asking quite a bit from those 60 horses. No first hand experience, but figure less power than a 582, and go from there. JImChuk

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    Default Re: Full Lotus and HKS power??

    Jim, no doubt asking a lot. But am I asking the impossible? By the numbers it should be closer to a 582 than a 503, and while the 503 was an option for the Fox I haven't found much in the way of performance or if any were ever on floats. I found a thread where you flew in a KF4 with a 503 and said it performed well, what would you have said if that plane were to be put on floats? I just really don't want to send the $2k for the rigging just to find out I can't take my kids fishing, or find I can't get in and out of the neighborhood float pond.

    Here's a couple videos I found that are promising. Of course its different planes on different floats, but it's what I have found...

    Challenger II with 503, pilot reports hauls 2 people well (PJ floats)
    https://youtu.be/CL4bMDP9xSE

    2 Challengers side by side, 503 and 582
    https://youtu.be/_MANsCi7Qm4

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    Default Re: Full Lotus and HKS power??

    I did fly with a guy in a super light (Light Squared) Kitfox 4 with a 503, and really was surprised by how well it did. A draggy set of floats will change things a bunch though I'm guessing. There was a guy in western MN that had a HKS in his Kitfox 3. Seems that he flew it mostly alone. It was on wheels. I do remember him saying something about 78 mph, not sure if that was topped out though, maybe best cruise. He went by the name Mnflyer on the forum I think. I also think he maybe sold the plane a while back. Maybe you can search on here to see if you can find any of his posts. I would think if he saw your question he would have given his imput. I do think if you had a 80 HP 912 it wouldn't be an issue, my Kitfox 4 with 912 performs very well on just 80 HP. Not on floats though, just wheels or skis. JImChuk

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    Default Re: Full Lotus and HKS power??

    I did a bunch of reading today and basically came away with the fact that a KF3 isnít really a good float plane, even with a 582. Itís a single seat plane. Too bad, but I saved a bunch of time and money. Too bad because it would have been a really fun and inexpensive way to rack up a bunch of ASES time.

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    Administrator DesertFox4's Avatar
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    Default Re: Full Lotus and HKS power??

    I had a model 3 with a 912 80 hp. and it would have been a great floatplane even with two good sized people on board.
    Especially on straight floats. Itís not the airplane.


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    Default Re: Full Lotus and HKS power??

    Youíre right, itís not JUST the plane. Itís the mission and the end state. My Quicksilver Sprint would fly off floats fine with its 40 HP, but itís single seat and has a 60 mph Vne. Iím sure the KF would work with 60 HP, but as a single seat plane. I want both seats to be filled. Personally, I never thought putting 80 horses on a KF3 made sense with the under cambered wing and a 100 mph Vne. But Iím sure it would get off the water at gross. It was also the only realistic 4 stroke option before the HKS was available (that I recall). We all build them different for a reason.

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    Default Re: Full Lotus and HKS power??

    You would like the 3 with an 80 hp. 912.
    80 hp. with an Ivo in-flight adjustable prop on a model 3 was a blast. Only until I flew the Factoryís STi with a 915 did I experience shorter or steeper climb outs. Fuel burn was miniscule. Cruise speeds and baggage capacity were the only drawbacks.
    A little under 4 years and 1150 hours of pure fun. Would have loved to try the 3 with the Big Bore 105 hp option.


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    Default Re: Full Lotus and HKS power??

    At some point of horsepower vs drag you are starting to describe a helicopter more than an airplane. The added weight of the HP (and floats) will also start to push a M3 into single seat territory. I felt my 3 was overpowered with a 582 and have not yet explored all the performance aspects of the HKS, but that is where I believe HP should be for the 1-2-3s. Itís gonna be a fun plane, itís just not a float plane.

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    Default Re: Full Lotus and HKS power??

    I know this is an older post, but felt it important to help clarify what will work on floats and what won't.

    My first floatplane was the Avid Flyer prototype (predecessor of Kitfox) powered with only a 40 hp Cuyuna 2 stroke engine. It was a very light (364 lbs on wheels), bare bones airplane, but even with only 40 hp it performed comparably to 150 hp Piper Supercub on straight floats. It easily hauled 2 people and was a blast to fly! (fwiw, the straight floats used on the Avid weighed approximately 180 lb range with rigging) See pics of Avid prototype below.

    I have also flown both an Avid Mark 4 / Bandit, and a Kitfox Model 4 on straight floats, both with 503 Rotax 2 stroke engines. Both were super fun, very good performing floatplanes. I would compare them to an 85 or 90 hp J-3 Cub on floats (vastly superior to a 65 hp J-3 on floats). I also did some test flying on a Model 4 Kitfox with a 582 on Full Lotus straight floats. That was a super fun floatplane, even with 2 full grown men in it.

    Regarding the HKS: A guy I knew converted his Avid B (or maybe a C?) model from a 582 Rotax to the HKS 4 stroke and loved it. He said it weighed and performed similar to the 582 but had better torque in the mid to lower rpm range, the area used typically for cruising. So based on what he experienced, I wouldn't discount the power of the HKS. Even if it only was comparable to the 503, it would still work well on floats.

    A Model 3 Kitfox has the original undercambered airfoil like the Avid had, which makes for a great wing on a floatplane as it makes gobs of lift at lower speeds. So, I wouldn't underestimate the Model 3 Kitfox as a floatplane. I think it would be a super fun little floatplane that could be one of the least expensive to operate floatplanes ever built (I heard the HKS burns under 3 gph).

    By comparison, an 80 hp 912 Model 3 Kitfox on straight floats, set up properly would be a rocketship. So it would only makes sense that a 60 hp Model 3 on straight floats would still be a good performer.

    Now, if we start talking about amphib floats, that changes things. But I think the HKS Model 3 could still work. But the gross weight limitation of the Model 3 likely would make that a 1 seater by legal definition.

    Disclaimer: Free internet advice (smile)
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