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Thread: Weights for flight testing

  1. #11

    Join Date
    Aug 2011
    Posts
    162
    Use whatever is cheap and easy for you. OEMs do use lead, but steel works just as well, and it is MUCH cheaper. The main concern is that the ballast is properly secured, especially if it is located behind occupants. It would be tragic to be in a survivable crash but be fatally injured by flying weight (it happens). OEMs typically bolt it in (or put it in a box that is bolted in). Seat rails are a good place to secure it. Also remember that the G loads may becoming from any direction. Flight test safely! ��

  2. #12

    Join Date
    Aug 2011
    Location
    Marietta, GA
    Posts
    614
    I've used weight plates in gym bags secured by seatbelts. Not sure that would stand up to a 10 G impact, but I was comfortable with the setup.

    Not sure what I'm gonna do on the RV-10, which will require 6-700 pounds of ballast to test properly. One thing I don't want to do is schlep anything that weighs over 25-30 pounds up on the wing and into the airplane, so...

  3. #13

    Join Date
    Aug 2011
    Location
    Jackson MS
    Posts
    13
    Two anecdotes on 'ballast'.

    Years ago, before I got my license, I saw an older Vari Eze that had some cloth bags of lead shot in the nose for ballast. The owner was doing some maintenance & noticed some shot scattered around the floor of the plane. The cloth bags had rotted, and the shot had started spreading around the airframe.

    While I was training for my private ticket in an old ragged Luscombe 8A, we went through about a month of bad weather, with rain almost every day and constant low ceilings. Finally got a good day to fly, so headed to the airport. Topped it off, drained the sumps, propped it off, untied, & headed for the runway for solo T&Gs. Takeoff was completely normal feeling. 1st T&G, seemed like it took fewer turns on the trim for approach, and more to set up climb attitude. 2nd one, it definitely did. 3rd, I ran out of trim on climb out & had to hold forward stick in the climb. Must have looked...unusual...because the tower radio'd to ask if everything was alright. Last landing was 3 point holding heavy forward stick. Taxied back to the tiedown, wondering what had happened. I noticed that there seemed to be a couple of drips from the belly, under the baggage area. I saw that the water was dripping from a small hole (remember, student pilot at the time), so I got a small screwdriver & poked at it. Instant stream of water. Moving aft, I poked the hole at each bulkhead & got another stream. The old fuselage was so dirty, the years of grit, dust, etc had plugged up all the weep holes in the fuselage.

    Even though this was a taildragger, the water that entered the fuselage during that 'monsoon season' stayed in the cabin area until I got it sloshing over the bulkheads on climbout, with every T&G moving the water farther aft.

    So don't think that water (or sand, or shot, or...) will necessarily drain forward...

    Charlie

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