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What have folks used for ballast during Phase 1 flight testing to explore and prove the flight envelope? I need to perform some max gross weight testing as well as aft CG testing and am trying to figure out a safe/secure way to add weight to the plane.

I hear Cement bags and or sand bags work great if you have a canvas duffle bag to put said sand or concrete bags then secure that with a seatbelt.

Large bags of sand worked for me in a canvas bag. That was secured in place by the shoulder and lap belts.

The obvious statement is make sure it’s going to stay there.

I used a small carry-on suitcase to hold bags of mortar mix (...sand, cement mix, all the same). Buckle it in like a passenger, off you go!

I used my old Army duffel bag and put bags of pea stone inside (the duffel was in case any of the bags sprung a leak), and seat belted it in. The duffel has straps, so I put the seat belt through the straps "just in case."

I needed water softener salt at about the same time I needed to do my gross weight testing, Strapped in like a passenger in the right seat. 4 bags, 160 pounds. Close to the FAA standard person.

Borrowed these from my gym:



20kg (44lbs) weights.
They don't take up much space and can be secured using the seatbelts.
In the end I had 4 in the passenger seat and 1 in the baggage compartment.

I had a coal stove in my shop so my first "passenger" was Old King Coal. in 40 pound bags. Each bag in a large trash bag to help keep interior clean.

David A.

Being close to automotive work, I borrowed a “water dummy”. I could work with any weight by filling or siphoning off water. Perfect for my center stick Sonex. If I’d had dual sticks, I would have had to remove the right one for these tests.
Happy Landings
John
N50NX

I used 60lb bags of concrete mix. I wrapped them in additional heavy duty garbage bags as well to prevent any kind of mess.

I chose 60lb bags because it gave me a good weight range. I started with 2 at 120 lbs to make sure everything was good, then added another to get to 180 which is about the average FAA adult, and then 240 which put me right at gross. I strapped the bags together with ratchet straps and secured them tightly with the seat belt. Worked out well.