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Thread: How to put a Piet on a diet?

  1. #21
    EdM24680's Avatar
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    I've built a FlyBaby and worked on a Piet. Within specification limits for wood density, try to get the lightest materials in spruce and plywood. There is a lot of it in the Piet and care in selection is needed. Covering can be heavy too. Use Dacron and the lightest finish you can find. Don't use thicker gage metals as they are heavy too. I was a heli aerodynamicist for 6 years and landing speed and stall speed are a function of wing loading - pounds per square foot. Excess hp gives you only greater rate of climb and usually costs weight - engine + extra fuel. Lift devices are only good when extra thrust is available to pull the extra drag. The safest weight reduction is around one's waist!

  2. #22
    Have you considered the steel tube fuselage? I hear it's lighter.

  3. #23

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    Piet on a Diet

    Hi Rob - I'm no expert, as I am starting to build a Piet; and I have the same problem, I am not a small guy either!! I agree with one of the other replies, that the better Piet is the one built to the plans - just read the build articles by Mr. Pietenpol to understand why.
    If you look through the records for existing Piets, and note their empty weights, you will see there is a wide variation. If you want light, you have to eliminate all the optional stuff: no starter or electrics (wiring, battery, alternator, switches, electrical gauges, etc.), use Sitka, not Douglas Fir, minimum paint, no radio, maybe even one-piece wing! You will probably want to include brakes and tailwheel, but those are optional too, if you are up to that challenge! All these things are compromises for either convenience, comfort or cost. Safety is non-negotiable, so stick with the proven plans as Bernard intended.
    It is just a process of using aircraft materials, but only what is needed to do the job. We tend to add stuff during the build to make it our own, and those often add weight. Stick to the plans and you will have as light as possible, with a robust, safe, aircraft.
    Me, I plan to lose some weight to improve my situation - I just have not figured out exactly how I will do that!!

    Good Luck,

    Mark

  4. #24
    cluttonfred's Avatar
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    You might also consider the Oratex fabric covering system. It uses a heat-activated adhesive (something like tiny little beads of hot glue suspended in water) pre impregnated in the fabric and painted on the structure and attached with an iron. The fabric is pre-tinted and the whole system appears to be very easy to use, though it's not cheap. It could easily knock 10 lbs off the finished weight of the aircraft vs. even a light traditional Dacron covering job. See http://www.g-tlac.com/oratex.html and http://www.oracover.de/index.php/kat...ex_ul_600.html. The colors are limited and not as vivid as other systems, but should work well for an old-fashioned look for a Piet': antique (cream) and Fokker red or Corsair blue, for example.
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  5. #25
    highflyer's Avatar
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    The best and easiest way to trim weight from a Pietenpol without hurting strength and durability is simply to use Orrin Hoopman's steel tube fuselage option. It is quite a bit lighter than the standard wooden fuselage. Also leave off the starter and electrical system and battery. That alone would give nearly the 80 pounds you are looking for.

  6. #26
    Use a Lithium starter battery to save 10 to 15 lbs

  7. #27

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    Rob
    Advice from the UK, use the "Jim Wills wing", it's a built up ply and spruce spar 3 piece design actually approved by the LAA here (hard to do) and weighs a lot less than the routed solid spar!
    Look for more info here: http://www.pietenpolclub.co.uk/
    H
    ave fun,
    English Johnny

  8. #28
    cluttonfred's Avatar
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    Did anyone find a source for the Wills wing modification at this site or elsewhere? I didn't see it there.

    Quote Originally Posted by johnnysdrop View Post
    Rob
    Advice from the UK, use the "Jim Wills wing", it's a built up ply and spruce spar 3 piece design actually approved by the LAA here (hard to do) and weighs a lot less than the routed solid spar!
    Look for more info here: http://www.pietenpolclub.co.uk/
    H
    ave fun,
    English Johnny
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    cluttonfred.info
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    and other safe, simple, affordable homebuilt aircraft

  9. #29

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    At the UK site- found this- hope it helps.
    http://www.lightaircraftassociation....0AIRCAMPER.pdf

  10. #30
    cluttonfred's Avatar
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    Thanks, but the LAA type sheet seems to point back to the same web site noted above. I wrote James Buco to ask him directly.

    This whole thread has got me thinking how I might build a Piet' within the 450 kg (472.5 kg with ballistic chute) gross weight limits for a two-seat microlight in Europe. That would be great fun and seems quite doable, especially with the steel-tube fuselage and Wills wing.
    Last edited by cluttonfred; 05-15-2012 at 12:53 AM.
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