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Max gross weight testing

JackinMichigan

Well Known Member
In the process of writing up a detailed test plan in preparation of the first flight. I've based it off a couple other RV test plans I've come across. Towards the end of the test plan I have "max gross weight checks", which is where you load the plane down to it's maximum takeoff weight of 2,700 pounds and perform some basic flight maneuvers.

To get up to this weight I will need an additional 700 pounds of ballast on top of my fat a$$. I originally thought of getting a bunch of sand bags, but my father shared with me a horror story of someone else doing that. Apparently the bag broke open and the sand poured into the tail, which threw him so far out of balance that he lost control and crashed.

What's a good ballast material that won't cost a fortune, stay put inside the airplane, and not soil up the upholstery?
 
I used 40# bags of mulch. Some have used bags of water softener salt pellets or cement. The idea was to use something that's easy to get and useful after the test flight. Whatever you use just insure you put down a drop cloth and you shouldn't have any issues if a bag springs a leak.
 
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The issue is not sand, it's the containment method.

My 10-friend used sand, I will re-use his sand. Nothing wrong with that. Just take some tarp and sit the bags on it and wrap for protection then make sure you have it all strapped down. Just do what is necessary to avoid breakage and leakage.

I had rather have this than 50# cast iron weights :eek:
 
I used 40# bags of water softener salt pellets. The bags are sealed well and very thick. I was then able to use the salt in my softener after I was done testing.
 
Quickcrete

I used 80# bags of Quickcrete, wrapped in plastic from Homey Depot. Figure they'll get used on some back yard project.
 
I used cases of bottled water. Figured if one broke it wouldn't be a big deal. Because of their bulk though, I calculated the cg of each case. Had them stacked in the rear baggage compartment, on the rear seat and even on the floor protruding up the sides of the front seat. Made sure they were secured well. I was able to get to max gross at max aft cg. Afterwards just kept the cases in the hanger to drink. Just about gone now, 3 years later. Beware, stick pressure feedback reverse is real!
 
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Me too

Cases of oil, 25lbs., 24 packs of soft drinks, 12 packs of soft drinks and ice tea 12 packs and so on. You can load what you want for the testing then stack it up next to the beer frig in the hangar or the house and use it tell it is gone.
Win-Win kind of thing and yes if you use oil it goes in the airplane, we hand 6 or 8 cases so we used them then put it back on the shelf for later.
Just what we did. Yours, R.E.A. III #80888
 
Water containers... Whatever you own or can borrow...

The idea of putting something abrasive or corrosive in my new airplane did not appeal to me...

This was an RV-8 @ max gross & rearward C/G...




 
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I'm a bit curious about your numbers: 700 lbs plus yourself? Either you have a very light -10, or are planning on less-than-full fuel?
Either way, approach aft cg with caution. Remember that you have to come back to land, and as you burn gas the cg will move further aft.
 
Hey, what do you know. You're right. I apparently forgot something in my initial calculations.

2700 - 1673 (empty wt) - 360 (60 gal fuel) - 250 (my butt) = 417 lbs.

That's a little more manageable. Thanks for catching that.
 
I strongly urge all -10 owners to write or obtain an Excell or similar spreadsheet for weight and balance. The issue is CG. There are a lot of -10's out there that can exceed the aft limit when loaded unless care is used. And, as I noted, you can start out okay but go out of limits during the flight due to fuel burn.
 
+1

I strongly urge all -10 owners to write or obtain an Excell or similar spreadsheet for weight and balance. The issue is CG. There are a lot of -10's out there that can exceed the aft limit when loaded unless care is used. And, as I noted, you can start out okay but go out of limits during the flight due to fuel burn.

This. I copied an Excel W&B sheet and modified for my plane. It has 2 separate graphs-- takeoff and landing. I run both to insure I'm good to go as I burn fuel.
 
I strongly urge all -10 owners to write or obtain an Excell or similar spreadsheet for weight and balance. The issue is CG. There are a lot of -10's out there that can exceed the aft limit when loaded unless care is used. And, as I noted, you can start out okay but go out of limits during the flight due to fuel burn.

I also noticed recently when I did my W&B that a lot of the reported numbers for wheel positions from the datum were exactly the same as what Van's publishes in their example sheet. My main wheels were something like 1.5" different from that (and I checked these measurements multiple times). I contacted Van's about the difference and they told me the published numbers are from the RV10 prototype and that our kits may very well be different.

I suspect there may be some 10's out there where the CG is not where expected even when doing the math correctly.
 
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Kroger water bottles packs of 24

I used the 24 packs of water bottles from Kroger. They weigh about 25lb each. The plastic wrap is pretty strong. 5 in the luggage compartment, 5 on each rear seat. The rear seatbelts holds them together well. Then have observer pilot with me, full tanks and I was at gross weight and not full rear CG.
Will still use the water later!
Johan
 
If you have Foreflight on your iPad, you can use the W&B portion to give you a plot that shows your CG with both full fuel and empty.
 
I used a heavy friend in the right seat of my RV6, and in the back seat of my RV8 - strapped in with a seat belt. Also needed a little baggage in both cases. This is allowed, in fact recommended, by our local FSDO in Cincinnati. It's also allowed to include a safety crew member during flight test for recording important flight test data while the test pilot is busy conducting the flight test and unable to record data. Too many cases of ballast shifting and causing possibly dangerous conditions, or test pilot being unable to notice or write down critical flight test information because of his/her focus on precise flight path control.
 
I used a heavy friend in the right seat of my RV6, and in the back seat of my RV8 - strapped in with a seat belt. Also needed a little baggage in both cases. This is allowed, in fact recommended, by our local FSDO in Cincinnati. .

A "friend"? Did they understand this was during phase 1 operations?
I guess some FSDO's just make up the rules as they go along....If your operating limits say something else, I wouldn't count on the FSDO coming to your rescue, should you get "caught".
 
Of course my friend was fully aware of what we were doing and that we were flight testing. In fact he did the same thing when he did his flight testing. It's clearly understood that this is not a joy ride. No worries about getting 'caught', since it was what is recommended by our FAA inspector. He has seen too many cases where ballast has shifted and caused bad things to happen. This type of testing is accomplished later in phase I, after engine and airframe reliability has been proven, and after controllability/stability testing is complete. It isn't something that our Cincinnati FSDO just 'made up'. It is well established, and approved.
 
Yes, you can follow the Additional Pilot Program for Phase I:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_90-116.pdf

True, but it can't just be any schmuck pilot off the street until the Initial Test Package (ITP) is completed by the builder pilot. Until that's done then the addional Pilot has to meet "Qualified" Pilot criteria (a min score of 60 on the Recency-of-Experience matrix and a min score of 90 on the Experience Qualification matrix).

I would also make sure your OPLIMS support it. The current wording out of 8130.2J is "191(g) & (i) AFS-800: Unless operating per FAA AC 90-116, Additional Pilot Program for Phase I Flight Test, only the minimum crew necessary to fly the aircraft during normal operations may be on board."
 
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APP

Yes, as I stated, "you can follow" the APP program.

Personally, I think it is a great program. With two qualified people on board, one can concentrate ONLY on flying, the other on systems. That is how we do it professionally and it should be a good thing experimentally, too. Assuming, as you say, it is not just "some schmuck" looking for a ride...
 
Ballast

I can add an additional 280lbs, but you'll have to swing by Jacksonville Florida and pick me up. Thinking of building a -10, and would love to fly in one first...
 
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