Shrinking down a two seater

Discussion in 'Hangar Flying' started by Little Scrapper, Feb 19, 2019.

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  1. Feb 20, 2019 #21

    lr27

    lr27

    lr27

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    I should think there'd be something out there already that would fit the bill. Possibly one of the older designs. Is the BD-6 any good? Can it be scratch built? I suppose a Fly Baby would be too slow and drafty. Any speculation like this is probably fruitless, though, if we don't know the mission, what you're willing to build with, performance required etc. OTOH, if you're LOOKING for a design project, I'm sure you could figure out how to narrow a Tailwind or Buttercup.
     
  2. Feb 20, 2019 #22

    TFF

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    I think the limit is getting it out the door.
     
  3. Feb 20, 2019 #23

    dougwanderson

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    That would be the bear hawk LSA
     
  4. Feb 20, 2019 #24

    cluttonfred

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    +1 on Tiger Tim's suggestion of the Stits Flut-R-Bug if you can find a set of original SA-6B plans, welded tube like you prefer and just 18' or so long. It's a plane that just screams flying around for fun, makes me smile.

    Flut-R-Bug cutaway.jpg

    If you want to maximize the amount of plane that will fit and don't mind wood, then an Evans Volksplane VP-2 fuselage happens to be 34" at its widest point and the whole plane is 19' 3" from the prop hub to the stabilator trailing edge.

    VP-2 overview.jpg
     
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  5. Feb 20, 2019 #25

    Little Scrapper

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    The limit is definitely getting it out the door. I really appreciate the recommendations, especially the stuff that's odd or rare which I like.

    It has to be steel. I tried wood and it just wasn't me. I like to be challenged and I like things that are unique and not real common. The fun for me is definitely in the fabricating, I really miss that.

    Because I need to move around the shop the smaller the better.

    I talked with Earl Luce and he convinced me not to shrink the Buttercup and had good reasons.

    My biggest issue is I seriously just like them all. Even the bizarre stuff. I thought of putting a 23012 wing on a Baby Ace and maybe that might be a unique challenge for me. A little Biplane perhaps? But not Baby Great Lakes little, I sat in one and that was just too much wing in my face. Smith is nice. A super light weight Pitts is a dream that many have including myself.

    The Little Toot was a neat suggestion. A Hatz is always a good idea.

    I have easy access to a couple small Continentals which could be smart to use.

    I don't know. I'm only a hour from Oshkosh maybe I'll take a day off in the next couple days and walk the museum for ideas. I'm really looking for a challenge that's at least somewhat unique. Unique challenges in life seem to hold my attention well.
     
  6. Feb 20, 2019 #26

    Turd Ferguson

    Turd Ferguson

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    The Bearhawk Patrol and Bearhawk LSA are two different planes. Two very different planes.
     
  7. Feb 20, 2019 #27

    Pops

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    My JMR is sort of a narrowed down to single place Buttercup design, also there are some Baby Ace, etc, etc. Fuselage 28" wide steel tube and wood wings. Used a 2414 airfoil. Stated designing aluminum wings for it but not finished. Maybe some day. I ask my sons and grandsons if any would be interested in marketing a set of CAD plans in the future and maybe supplying engine mounts, fuel tanks, landing gear, etc. Several are engineers but their lives are busy going in other directions. I have no interest in starting a business. After Dallas and I built all of the hard tooling for the Bearhawk and built 4 for ourselves, we had many request to build many more and turned them down and we sold the tooling . We are retired and plan on staying that way. Mark Goldberg ( Bearhawk factory) ask me if we were thinking of going in business selling Bearhawk parts no kits, we told him NO. For the scratch builders, Dallas will make some small parts if someone is in a bind about making something and even through they have plans, Dallas pays Bob Barrows a certain percentage for the right. Dallas just does enough to have something to do that he likes in the shop.
    LS-- I always liked the Stits Flut-R-Bug. Steel tube fuselage and simple wood wings. Small enough for your space and tried and proven. Front seat is very small but use it single space with lots of front baggage room for the fly-in camping. There was a single place Flut-R-Bug for sale on Barnstormers a few months ago.
     
  8. Feb 20, 2019 #28

    Pops

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    Yes, after coming out with the Patrol, Bob had many request for a LSA type of Patrol, but its a completely different design. They do use the same airfoil.
     
  9. Feb 20, 2019 #29

    BBerson

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    The Cygnet is steel tube fuselage. Geodesic wings, single strut. View would be fantastic with forward sweep and single seat view out both sides.
    I think single seat conversion for a big guy is a great idea.
     
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  10. Feb 20, 2019 #30

    Little Scrapper

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    I've always thought it was a great looking airplane. I don't know much about it, definitely unique.
     
  11. Feb 20, 2019 #31

    Little Scrapper

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    I stopped home because I have a 45 minute gap between service calls this morning. I pulled out a set of Pitts drawings. It's amazing comparing the complexity of a Pitts to something like a Smith or a Hatz. A Pitts is quite daunting, amazing how much detail went in to that airplane.
     
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  12. Feb 20, 2019 #32

    Toobuilder

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    Narrowing a Hiperbipe would be both easy and a bit of a challenge. Easy, because the kit featured tacked fuse sides and the builder simply had to add a stack of cross pieces (all the same size) to frame out the fuselage. Pulling 12 or 20 inches out of that cross piece dimension would result in the identical geometry. Wings, wires, tail... All expensive bits that would not know the difference since they all attach to the sides of the fuselage. Where it gets tough is re working the stab and elevator to proper area (any reduction in fuse cross section is a reduction in stab span), and of no simple matter is the flaperon drive assembly mounted right at BL 0. On a side by side this is no issue, but with the pilot mounted in the center...

    Of course you'd want to delete one door, come up with a new engine/gear mount, cowl, and windshield too. But much of an unfinished kit could be retained. Even the fuel tank could be narrowed and otherwise mounted as designed. And with the lighter empty weight, you would NEVER break it in the air.
     
    Last edited: Feb 20, 2019
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  13. Feb 20, 2019 #33

    billyvray

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    This.
    I think you want Ed Fisher's Lil Bitts.
     
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  14. Feb 20, 2019 #34

    Little Scrapper

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    That's a 2 stroke powered airplane i believe. I'm ok with certain 2 strokes on certain airplanes but not a biplane. It's a beautiful looking little biplane but not a good combination for me personally.
     
  15. Feb 20, 2019 #35

    ScaleBirdsScott

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    I don't see why a Lil Bitts couldn't handle a 4-stroke engine? It's basically a Micro Mong and those have handled 4-strokes. The Pegasus, the Briggs, the HKS, (and a few Other choices to round out the options) all seem like they could work.
     
  16. Feb 20, 2019 #36

    Little Scrapper

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    Continental & Lycoming is really what I'd prefer to fly behind. I'm not necessarily "anti" the alternatives I just like those two options much better.
     
  17. Feb 20, 2019 #37

    dcstrng

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    Scrapper; For different reasons I've pondered the same thing from time to time -- more based on a W8 than a Buttercup, but at least one builder has done it successfully... I've got a Cougar fuselage in my shop that I've thought about narrowing (yeah, I know all the graduate engineers are running for the exits -- fortunately I don't know any...) and bought the tubing, but so far haven't pulled the trigger.

    Please see: http://www.homebuiltairplanes.com/forums/showthread.php?t=30154&highlight=larson+11
     
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  18. Feb 20, 2019 #38

    wsimpso1

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    Scrapper,

    Going either way is not a huge fuss, but going narrower is easy - the tubes in the plans are usually sized based upon the highest compression load on them, and thus their resistance to buckling. So narrower can be done just by keeping all of the tube sizes - only the length of the ones going between left and right walls will change and they only get shorter.

    Now if you wanted to optimize, Evan's Light Plane Designer's Handbook has charts for steel tubing compression limits based upon the standard tube sizes and lengths. For each tube that you will be shortening, you can look up the tube size, length, and look at its compression limit, then look at the new length and that compression limit, and see if a smaller tube will do the same job. If you go from a length of 42" to a 32", you can usually go down one size. Another option is that there are doors on both sides of the Buttercup and Tailwind. As a single, you only need one door, but the structural adjustments on the non-door side might take a bit more engineering if you were to save any weight.

    Billski
     
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  19. Feb 20, 2019 #39

    wsimpso1

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    When I have talked with Earl Luce, he has concluded we can skip the drooping leading edge, it does hardly anything for the bird.

    The plans indicate that the Buttercup can be built to 42" wide cabin. Going down 7" is to 35". A standard interior door is 36". Scrap, you looked brawny when I met you, but you did not look like you would fill a doorway, and you fit in a Cub. Going to what many of us find to be a roomy 32" wide cabin is 10" shorter and will usually allow going down one tube size as well as less length on a bunch of tubes across that airplane could save significant weight. Or stay with the plans and just shorten all of the tubes.

    Converting it to a single would tempt me to reduce the chord on the wing a little. Ah, let's not even get into that...

    Billski
     
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  20. Feb 20, 2019 #40

    TFF

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    I believe the Pitts plans just have more detail than a Smith or Hatz. I think there is more rolling your own with the other two. I don't have a copy of the Starduster One plans but I have seen them and they are only 5-6 pages total. My restoration of my SD1 has not needed any real measurements even though I had to do some welding and bending; everything was good enough as templates or freestyle. Pitts and AcroSport plans have all the details for the builder to see. 33 Sheets for the Pitts plans I have; Acrosport One is about the same. I think original Skybolt plans are about ten sheets.
     
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