Volksplane VP-2 Mk2 wing project

Discussion in 'Wood Construction' started by FritzW, Oct 1, 2018.

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  1. Oct 1, 2018 #1

    FritzW

    FritzW

    FritzW

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    A while back I got infatuated with the idea of an improved (lighter, cleaner, simpler) VP-2 wing. When the SolidWorks models were finished a VP friend of mine, Bill Fluhr, decided he wanted to build a set for a VP-2 he's restoring. Last week he brought over a bunch of really nice Doug Fir spar blanks and a couple of sheets of ply.

    20180919_165357_resized.jpg Bill got the fun job of running the vacuum cleaner while I sat on my butt and kept an eye on the machine.

    20180919_171832_resized.jpg We got one spar finished before I trashed the computer (I turned off the main power while it was shutting down). The spar came out great but the computer is smoked. ...I'm waiting for amazon to send me a new hard drive. I don't know what I did but I crashed the dog poop out of it :ermm:


    VP-2 Mk2 wing 1.jpg The VP-2 Mk2 wing. Solidworks says they'll weigh about 32 pounds a piece (~20 pounds lighter than PtP wings)

    VP-2 Mk2 wing 2.jpg Everything except the rib corner blocks are cut on the CNC machine

    VP-2 Mk2 wing 3.jpg Differential ailerons (bellcrank in picture)

    VP-2 Mk2 wing 4.jpg Proper A/R ailerons with false spars

    VP-2 Mk2 wing 5.jpg Piano hinges instead of eyebolts, no gap seals required

    VP-2 Mk2 wing 6.jpg All the little PITA details like strut cutouts on the ribs are pre-cut

    If the UPS truck brings my new hard drive today I'll finish the wing 'kit' in the next week or so.
     
    Sockmonkey, mcrae0104, Pops and 4 others like this.
  2. Oct 2, 2018 #2

    Twodeaddogs

    Twodeaddogs

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    that's brilliant! Nice one!
     
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  3. Oct 2, 2018 #3

    plncraze

    plncraze

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    Your SolidWorks renderings are stunning. The fact you can program a machine to cut the stuff is mindboggling. Years ago I knew someone who worked for Boeing when they were getting the 777 computer program to design and build a plane in virtual environment was just getting started. He knew C++!!! Watching you do it in your garage is incredible.
    Question: why not go cantilever with the wing?
     
  4. Oct 2, 2018 #4

    Victor Bravo

    Victor Bravo

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    Are you going to put the little slotted 90 degree plywood stiffener strips into the rib diagonals like the other wing you drew? That was a reeally neat idea IMHO, seems like it would keep everything aligned in the right plane from moving around. And almost no additional time/efforrt to install

    Add my vote to the cantilever crowd, for whatever it is worth. I know it means a different wing. And I know it is no longer a VP-2 restoration at that point.

    But in terms of your being the de facto champion of the VP in these waters, and being unanimously voted as "most likely to offer a Volksplane kit", for any future wood VP-1 and VP-2 efforts I have to vote strongly for cantilever.

    How much more does a Spacewalker wing weigh than a Volksplane wing with the steel struts? That would be an interesting and valuable thing to model in Solidworks and have the computer weigh it.
     
  5. Oct 2, 2018 #5

    FritzW

    FritzW

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    The whole thing is mindboggling to me also. The fact that you can draw a photo-realistic gizmo on the computer (with virtually free software) and with a few mouse clicks have 3,000 lines of G-code sent to a CNC router or a 3D printer is beyond my comprehension.

    I thought about a cantilever wing but the ripple effect would be huge and would require, pretty much, a whole new fuselage.
     
  6. Oct 2, 2018 #6

    cluttonfred

    cluttonfred

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    Great stuff, Fritz, I’ll obviously be very interested in how this turns out. If you can save 20 lb each just on the wing panels, then 60-80 lb total savings seems quite attainable by applying the same techniques to the fuselage and tail. That’s a huge improvement!

    VP-IICutaway.jpg 2.jpg VP-2 Mk2 wing 4.jpg

    For anyone not familiar with the stock VP-2 wing construction, here is a side-by-side comparison (I rotated and flipped Fritz's rendering) and a cutaway.
     
    Last edited: Oct 2, 2018
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  7. Oct 2, 2018 #7

    Twodeaddogs

    Twodeaddogs

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    you shave 60-80 pounds off a VP-2 and then the 1834cc could be a realistic engine.
     
  8. Oct 2, 2018 #8

    cluttonfred

    cluttonfred

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    ...as a single-seater! ;-)
     
  9. Oct 2, 2018 #9

    FritzW

    FritzW

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    You could put an IO-540 on a VP-2 and it'd still only be a single seater :gig: (unless you only fly with little kids or leprechauns) No matter how much a VP-2 weighs or what size engine it has, it's still only 34" wide at the nalgas and the leg hole and seat bottom are still only 28" wide. If a VP-2 is ever going to be a real two seater it's going to have to be 10" wider (doable) or have tandem seats (also doable).

    I was being generous when I implied that a PtP VP-2 wing panel weighs 50 pounds, it's more like 60 or 70 (a stock VP-1 wing panel weighs 55 lbs and it's smaller and a much lighter design).

    Saving 100 pounds on a VP-2 would be pretty easy to do. I think an 1835 would work fine on a light VP-2. I don't know what size engine Evans used on the prototype but I'd bet it wasn't bigger than an 1835.
     
  10. Oct 2, 2018 #10

    cluttonfred

    cluttonfred

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    Ex-U.S. Navy pilot (and, I think, fellow Convair engineer) Bill Beatty did the full test program (but not the first flight) of the original VP-1 and later the VP-2 for Bud Evans. Per Beatty in FLYING THE EVANS VP, the original prototype VP-2 "operated well" with 1835cc, 2070cc, and 2180cc engines, though that begs the question why they kept moving to bigger engines. According to test results, the difference between the 1835cc and 2180cc engines was just 700-750 fpm climb solo and 400-450 fpm climb dual. The reduced weight would help, but I'd still want all the power I could get.

     
  11. Oct 2, 2018 #11

    BJC

    BJC

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    I suspect that if one were to reduce the weight, add wing tips, improve the streamlining of the windshield / pilot / turtle-deck (an enclosed cockpit would extend the flying season in many locations), and clean up the landing gear, performance would be much improved. But, in doing so, one has added complexity, cost, and build time.


    BJC
     
  12. Oct 2, 2018 #12

    lr27

    lr27

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    If the parts are to be cut out with NC, making a moderately tapered wing shouldn't add much, if any complexity. I suspect that, if one were to think in an unorthodox manner, a clean, simple canopy might be achievable. Made with, say, conically curved Lexan and plywood.
     
  13. Oct 2, 2018 #13

    plncraze

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    You can read Budd Davisson's pilot report on airbum.com. He flew it with the smaller engine.
     
  14. Oct 3, 2018 #14

    Pops

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    I overhauled the 1600 cc VW engine for the VP-1 that a friend of mine used to have and it flew good with the engine. I never flew it, but I did do some high speed taxi test down the runway about 5' or so off the ground several times testing the engine. Then it was flown the rest of that year and sold. The owner regretted selling it.
     
  15. Oct 3, 2018 #15

    plncraze

    plncraze

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    Al Backstrom had some ideas for cleaning up a Volksplane in an article on drag in Sport Aviation. He had a canopy with no compound curves and strut cuffs along with wheel pants. It was cool looking in a flat sided kind of way.
     
  16. Oct 3, 2018 #16

    lr27

    lr27

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    Probably Toward Better Performance part IV Feb. 1975

    Just a short article about cleaning up two planes.
     
  17. Oct 3, 2018 #17

    FritzW

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    If your in a hurry, buy a plane ticket, rent a 172 or drive your car. If you want to "slip the surly bonds of earth and top the wind swept heights with easy grace" for 10 cents on the dollar, build a Volksplane :gig:

    You can't make a silk purse out of a sows ear (which is exactly what I'm trying to do with $15,000 worth of of software and machinery). ...but it keeps me out of the brothels and bars and I'm having fun, so it's okay.
     
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  18. Oct 3, 2018 #18

    lr27

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    Even if you don't want to go faster or make it look prettier, you'd still get longer range at the same speed, or get away with a slightly smaller motor, requiring a slightly smaller airframe, smaller fuel tank.....etc. Still looks like a VP, doesn't it?

    backstrom's VP cleanup from towards better performance.jpg
     
  19. Oct 3, 2018 #19

    robertl

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    Fritz, is that a homemade CNC machine ? Also, a new, lighter wing, increased speed, turtle deck and canopy ! I think I have an old dusty set of VP-II plans lying around somewhere ! Hmmmm :)
    Bob
     
  20. Oct 3, 2018 #20

    FritzW

    FritzW

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    CRP4896_base.jpg I started with a basic kit from CNC Router Parts and made the table out of 2x4's and plywood.


    s-l1600.jpg s-l1600s.jpg I was on a budget so I went with cheap Chinese electronics off of ebay. So far (6 or 7 years) they've worked great.

    ...when I was surfing around for these pictures this morning I was blown away by how much more "home cnc" stuff is out there now and how much the price has come down in just a few years.


    Yep, that's how it all starts. :gig:
     
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