Thoughts on a new biplane design?

Discussion in 'Hangar Flying' started by cluttonfred, Sep 3, 2018.

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  1. Sep 3, 2018 #1

    cluttonfred

    cluttonfred

    cluttonfred

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    Thanks to the Hatz thread and other factors, I’ve got biplanes on the brain right now. I believe that a well-designed, open-cockpit biplane with classic lines will always have a place in homebuilding because of the association with WWI and the Golden Age. What would the HBA crowd like to see in a new biplane design? Power? Seats? Construction? Style?

    Personally, I think that there are already enough big LyCosaur-powered aerobatic and sport biplanes out there and we could use more LSA or even European microlight biplanes for getting your goggles-and-scarf groove on for a lot less money than a Pitts or Starduster or what have you. Yes, there is the Hatz LSA and the Kieblitz from Germany and Sherwood Ranger from the UK, but it’s not a long list.

    I could see a light, simple, affordable, two-seat sport biplane having great appeal, say 80-100 hp with a lighter microlight model and a heavier LSA version, not a replica but channeling classic biplane style. Here are a couple of possible inspirations: the timeless DH60 Cirrus Moth, the airy Leopoldoff Colibri, and the Javelin Wichawk for its side-by-side open cockpit.

    B5D34669-A8D9-4AB4-9557-4A2F9A64ADD7.jpeg A59E5255-6B14-405D-996A-EB630EA324D2.jpeg 0553030A-C93C-4316-8745-D07FC82281B4.jpeg

    Let’s hear your thoughts!

    Cheers,

    Matthew
     
  2. Sep 3, 2018 #2

    Chilton

    Chilton

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    Why not another classic, the Currie Wot, flew with the JAP in the beginning, and later even the Rover turboprop, seems to cover all options for single seat.

    If you want 2 seats the Hawker Cygnet drawings are around. Good starting point?
     
  3. Sep 3, 2018 #3

    fly2kads

    fly2kads

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    The idea of a modestly-powered, classically-styled biplane occupies an outsized portion of my airplane obsessed brain. I like the idea of being able to cruise around with a friend, low and slow, in vintage style. There are two ideas that I keep coming back to:
    1. An all-wood biplane with the simple, boxy lines of the Pietenpol. In my vision, the fuselage is ply skinned, de Havilland style. I see this one as powered by an O-200 or Corvair. Quickie sketch below:
    fly2kads_wood_bipe.jpg
    2. A steel tube / wood wing biplane in the style of many "commercial" biplanes of the late 1920s. (The Hatz would look modern in comparison.) Think along the lines of American Eagle, Fairchild KR-34 (pictured below), or Waco 10. I think a Honda Fit motor with one of the Air Trikes PSRUs could be cowled to look something like an OX-5.
    Fairchild_KR-34.jpg
    I had originally conceived of these concepts as being LSA compliant. With the advent of Basic Med in the USA, that may be less of a concern.

    Aerobatic capability is way down the priority list here, although I could see basic loop and roll maneuvers being executed when flown solo.

    For a single seater, I agree that the Currie Wot would be an excellent place to start. The LAA plans set even includes drawings for a VW engine mount! A larger displacement VW could do the trick. Pete Plumb's O-100 would also work well, about the same weight as the JAP, but with much more power.
     
  4. Sep 3, 2018 #4

    bmcj

    bmcj

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    Though these are all single seat, I’d look at the Skyote, Stolp V-Star, Der Jager, and Flitzer biplane for further inspiration.
     
  5. Sep 3, 2018 #5

    plncraze

    plncraze

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    Where are the Hawker Cygnet drawings? Are they through the factory as the old Sopwith ones were or are these floating around the internet? It is a neat plane from a cool contest which is why I am asking.
     
  6. Sep 3, 2018 #6

    Dana

    Dana

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    Fisher has, I believe, five biplane designs. There's the FP-404 I had and the "Classic" 2 seat version, the larger Celebrity, and their Tiger Moth replica and the Yougnster.
     
  7. Sep 3, 2018 #7

    WBNH

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  8. Sep 3, 2018 #8

    cluttonfred

    cluttonfred

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    The description text to that video does put me off a little, as does the elaborate steel wing jig.

    Sherwood Ranger XP Aero wing ribs being bonded to the main and drag spar, video shows application of special 2 part structural epoxy which contains a form of rubber to resist shock loading. All aluminium components have been corrosion proofed with a non toxic non hexavalent chromium treatment, thorough degreasing of metalwork is essential, along with scuff preparation of the GL1 plywood ribs. Careful attention of rib to tube clearances is critical ensuring enough of a gap to allow the adhesive to bond but not too much to create a adhesive rich area, air bubbles must also be eliminated.

     
    Last edited: Sep 3, 2018
  9. Sep 3, 2018 #9

    pictsidhe

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    There have been at least two Cygnet replicas built in the UK. BAe have stopped giving out drawings for liaility reasons :( But many are already out in the wild. The Cygnets are beautiful little planes.
     
  10. Sep 3, 2018 #10

    plncraze

    plncraze

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    Thanks for the info. There appear to be a couple of plans-built Cygnets out there.
     
  11. Sep 3, 2018 #11

    Riggerrob

    Riggerrob

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    You guys have the single and two-seaters well-covered, but what about the 3 - 5 seater biplanes that were popular with barnstormers? New Standard D-25 carried up to 4 passengers in an enlarged front cockpit. Weld on a ladder and add a side-door for easy boarding and your could haul more than 100 sight-seers per day!
     
    Last edited: Sep 3, 2018
  12. Sep 3, 2018 #12

    Tiger Tim

    Tiger Tim

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    The D-25 practically is a homebuilt. The fuselage is extruded aluminum angle riveted together, wings are all wood, and the tail is a mix of wood and aluminum truss. The trailing edge of the wing is low enough to the ground that a small step stool is plenty to climb in and the front hole has a large step on the side of the fuselage to aid getting in and out. About the only thing that could make it easier for you and me to make is to have un-tapered wings, but then it would just look like an Ag Cat.
     
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  13. Sep 3, 2018 #13

    Tiger Tim

    Tiger Tim

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    I think the real question might be to ask what hasn't been done yet. I bet if we put our heads together we could find fifty different homebuilt biplane designs of very approachable classic construction that you can get plans for right now, today. What popular features could possibly be missing from such a list?
     
  14. Sep 4, 2018 #14

    bmcj

    bmcj

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    I thought he was hinting at the LSA category.
     
  15. Sep 4, 2018 #15

    Little Scrapper

    Little Scrapper

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    The biplane space is pretty crowded with great designs already. There's pretty much a flavor for everyone including replicas.
     
  16. Sep 4, 2018 #16

    TFF

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    A biplane is the easiest airplane to personalize. Change wing tips, tail shape, deck and you have your own airplane. Gear options; stock or Grove aluminum changes it up. Almost nothing will change the performance enough to matter if you keep the wings where they are supposed to be along with the tail and engine. Biplanes like all homebuilts don't build themselves. It takes a little more effort to build another wing and buy flying wires. Funny thing about biplanes, everyone wants to try one on. The most hot shot pilot will stop and look at one; most planes they usually just walk on by.
     
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  17. Sep 4, 2018 #17

    Little Scrapper

    Little Scrapper

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    So true. When a biplane is overhead I just flat out stop and admire it until it passes. There's jusy something special about biplanes.
     
  18. Sep 4, 2018 #18

    BJC

    BJC

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    Since you asked ....

    There are lots of basic single seat flyer designs, but none that I know of that is proven, easier, or less expensive to build than the Airdrome Aeroplanes. Well-proven. I’m excluding the Hovey Wing Ding, because I have not been able to validate it’s performance, and because I believe that you are not thinking of that class of airplane.

    No two seaters that I know of have reasonable performance on the low HP that you specified.

    Among the higher HP single seat airplanes, the Pitts is by far the easiest and cheapest to build, as well as the best performing. The design is elegant, and it is much more streamlined than other designs, excepting one-off racers. A Baby Great Lakes may work for smaller people, and cost slightly less than the Pitts, but at a much lower performance level.

    Good performance on low HP, especially if a two seater, will require lighter weight and better aerodynamics than the current HBA designs available. That could be done in steel tube / wood / fabric, or even aluminum, but light and streamlined would be difficult.

    It could be done with a carefully designed composite design if people would accept the concept. Consider: with the short wire-braced wings, there is no need for a heavy spar, one wing mold for all wing panels, just use a shorter section for the lower wings, one mold for the vertical and horizontal stabilizers, ditto control surfaces, one fuselage mold for both the lower fuselage, and, with cut-outs, the upper fuselage. Use round flying and landing wires, streamlined with foam and plastic. Use composite tubes for push-pull controls, etc. Once the design and tooling costs have been recovered, airplane kits could be produced for a reasonable cost.

    Could be done, but who would go through all that effort for a design with such a limited market?


    BJC
     
  19. Sep 4, 2018 #19

    cluttonfred

    cluttonfred

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    The Fisher biplanes are close to what I have in mind, especially the larger Ceebrity and the Tiger Moth scale replica. I don’t know that Airdrome Aeroplanes currently offers any very practical two-seaters.

    In terms of power, I do think that 80-100 hp should be plenty for a two-seat sport biplane as long as your expectations of performance are in line with the modest power. Think J-3 Cub with a C-85 not Valdez super STOL competitor.

    The 85 hp Genet radial-powered variant of the DH60 Moth was reputed to be a pleasant flier and used by the RAF for an aerobatic team, and that was still a fairly heavy plane with a gross weight of about 1650 lb/750 kg. An LSA biplane would be 20% lighter at 1320 lb/600 kg and a microlight a whopping 37% lighter 1040 lb/472.5 kg.

    What do folks think of the side-by-side open cockpit vs. the usual tandem open cockpits for a two-seat biplane? With a VP-2 control setup (dual pedals, single center stick, sit in middle and use outer pedals when solo) it seems to me like a slick arrangement that would save a little time and weight and money over two cockpits and dual controls.
     
  20. Sep 4, 2018 #20

    Victor Bravo

    Victor Bravo

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    The Flitzer beat you to the punch, and did it with such panache that it would be very difficult to create something better in the "classic" flavor. The new O-100 engine, or the VW derivatives, or even the Verner radial, will make this little gem a classic in its own right, for those who want to build a classic.

    For those who want to have the look of a classic, but not the classic time intensive building methods, the answer is right in front of us as far as I'm concerned: Just use the well proven and simple Graham Lee / Baslee method of building WW1 replicas, and give it a very slight nudge (holding a gun to Mr. Baslee's head) to create a tube and gusset Fleet Biplane replica.
     
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