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Thread: Weights for flight testing

  1. #1

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    Weights for flight testing

    What type of weights are recommended or typically used to simulate passengers and cargo for flight testing at various gross weights and CG locations?

  2. #2
    Auburntsts's Avatar
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    I recommend using something that can used for another purpose post flight. I used 40# bags of mulch. Others have used bags of water softener salt, cement, potting soil, sand, dog food, cases of water, etc. I also recommend putting down a plastic sheet/tarp under whatever you use just in case a bag rips.
    Last edited by Auburntsts; 01-29-2018 at 07:17 AM.
    Todd “I drink and know things” Stovall
    PP ASEL - IA
    RV-10 N728TT - Flying
    WAR DAMN EAGLE!

  3. #3

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    lead shot bags used to be the aviation standard. 25 lb bags and you can work in 25# increments. They are also great for semi permanent ballast. Oh, they are also the most $$$

  4. #4

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    As others have said, use things for which you have a later use. One caveat re: bags of sand/soil, most Big Box stores have outdoor garden centers where rain could add considerable weight to exposed bags so that supposed 30# bag of sand could really weigh a lot more. Weigh before use. Dog food is a GREAT donation to your local shelter, cat litter makes a very good oil spill absorbent for a garage floor or as winter traction assist.

  5. #5
    Auburntsts's Avatar
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    As a side note for possible ballast once you’re in Phase II, I use collapsible 5-gal plastic water containers typically used for camping. I can easily add or dump water as required and the empty containers take up little space or weight. Very handy for flights where you are solo for one leg and then pick up pax/cargo on another away from home base.
    Todd “I drink and know things” Stovall
    PP ASEL - IA
    RV-10 N728TT - Flying
    WAR DAMN EAGLE!

  6. #6
    FlyingRon's Avatar
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    I'd recommend against water. The problem occurs if your water container breaks or otherwise leaks. Your 5 gallons of water is now 40 pounds of ballast that may end running way aft and putting you irrecoverably out of CG. It's happened in gliders (who often take water ballast along).

  7. #7
    CarlOrton's Avatar
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    I used 40lb bags of play sand. Yes, I weighed them first! I bought some cheap plastic drop cloths and wrapped the bags well to prevent sand "leakage." The last thing you want in a brandy new plane is grit all over the place.

    Carl Orton
    Sonex #1170 / Zenith 750 Cruzer
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  8. #8
    Auburntsts's Avatar
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    There is risk, admittedly, but it’s minimal IMO. Plus in my airplane any leak would drain forward and out of the plane.
    Todd “I drink and know things” Stovall
    PP ASEL - IA
    RV-10 N728TT - Flying
    WAR DAMN EAGLE!

  9. #9

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    This is where one starts polling folks in their EAA chapter to see who has the bags of shot. Chances are someone has an ancient set that have been in multiple projects.

    I know folks can and have used water as ballast, but I vote against it. If a hole is in a sand bag, it doesn't all flow out endlessly. It's one of those "odds are" things. Odds are that in normal flight the water jugs won't develop a leak. But what a mess if they do!
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

  10. #10

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    If you use shot for weight don't use this for ballast in your airplane. I speak of permanent ballast. I did this and the ballast bag moved just a little a slid against something that tore it. These bags get heavy. I then had shot all over my fuselage and my C/G could have changed if I lost enough of it. I used a sledge hammer head for my ballast. I had an old one laying around without a handle. Ran a bolt through the center and bolted it into place.

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