Setting the Gross Weight for the RV-12

How will Vans determine the gross weight for the -12? The -12 seems to be very well built. If structurally the -12 turns out to be strong enough for a gross over the 1320lb LSA limit, how would its gross then be reduced? To meet the 1320 limit, would it be a matter of 'safely' documenting the gross at 1320 if its actually capable of flying at a higher gross rather than unsafely documenting 1320 if it actually had a lower one? Just curious.


Mike

As an amateur-built the builder may set the gross weight. Now if you set it higher than the designer recommends, you DAR may question your documentation. You can always set it lower than the designers recommendation. But, be aware that if you set it higher than 1320#, it can never be flown as a light-sport aircraft unless the PIC holds a recreational pilot certificate or higher. This requires at least a 3rd class medical. An example of this is the American Legend Cub. The structure will probably handle a weight of at least 1500#, but that wouldn't pass for light-sport. So gross weight is set at 1320# for wheels and 1420# for floats.

Thanks Mel. I do find that a little confusing however. If the kit manufacturer (Vans or otherwise) documents the specs for a given kit as having a gross weight over 1320 and you build that kit as specified by the manufacturers instructions, how can you legally then document the gross as 1320?

Mike Armstrong said:

How will Vans determine the gross weight for the -12? ... If structurally the -12 turns out to be strong enough for a gross over the 1320lb LSA limit, how would its gross then be reduced?

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Mel (and others), correct me if I'm wrong, but if you're going to register it as a LSA, then you need to have a MGTW of 1,320lb max - period. If you want to register it as an experimental and have it qualify as a LSA, you need to limit MGTW to 1,320 lb - period. If you want to register it as an experimental and you don't want it to every be a LSA, then you can use whatever MGTW you want and the FAA/DAR will approve.

The RV-12 is an interesting case - it's not factory built, so it's not a S-LSA. Van's - supposedly - isn't going to certify it as an E-LSA, so that option isn't available, right? All that's left is to certify it as an experimental, and you can include in the OpLims a MGTW of 1,320 lb, 120kt, etc. to keep it within the LSA characteristics.

One interesting option you would have with the -12 would be to certify it as conforming with the LSA specs, then change the OpLims later and allow a max speed > 120kt and MGTW > 1,320 lb.

It just seems weird (dishonest/illegal) to put 'whatever you want' as the gross just 'cause YOU built it even though its been documented by the designer and/or kit manufacturer that it has a gross other than what you now say it has just to make sure you can fly it in a certain (LSA) catagory.

Mike -

There's nothing really dishonest about "derating" a structure or system - you are just giving it margin. I certainly wouldn't be comfortable going the OTHER way (giving it a gross higher than the designer intended), but virtually all of our airplanes, in effect, probably have a lower gross weight than they actually could - heck, in Alaska, many planes get an automatic gross weight increase.

Paul

Got it, thanks Paul.

RV-12

Mel's reply is absolutely correct. He was one of my best students.


Van Stumpner
FAA Aviation Safety Inspector
DAR Course Manager
AFS-610 Light-Sport Branch

But...

If you have no intention of flying strictly as an LSA... and are just building it because it is a nice little craft that will be easier, quicker, and slightly cheaper to build than other RV's...

Will Van's test and establish a "non-LSA" MGTW?

Mostly a rhetorical question. It appears to have a pretty decent load capacity as is. Maybe there will be enough brawn to the beauty that he'll cert if for a little bit of loops and rolls.

Let me clear up a point that some of you are making confusing. You refer to certifying as "experimental" as opposed to E-LSA. E-LSA IS experimental. You are confusing the word experimental with amateur-built. While amateur-built is indeed experimental, experimental is NOT necessarily amateur-built. Experimental can be amateur-built, exhibition, experimental light-sport, show compliance, etc. Using the correct terms will minimize confusion.
Unless Van first certifies the RV-12 as S-LSA, then he cannot offer an E-LSA kit. (FAR 21.193(e)(1)). The only option then becomes an amateur-built (51%) kit which meets the parameters for light-sport and may be flown by a Light-Sport Pilot.

Mel said:

Unless Van first certifies the RV-12 as S-LSA, then he cannot offer an E-LSA kit. (FAR 21.193(e)(1)). The only option then becomes an amateur-built (51%) kit which meets the parameters for light-sport and may be flown by a Light-Sport Pilot.

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Just when I thought I understood this stuff...

So if Van's does not certify the RV-12 as S-LSA (and thence E-LSA), it sounds like someone holding a light-sport pilot certificate can still legally build and fly an RV-12. Assuming the previous statement is correct, what further advantages accrue to either Van's or the potential light-sport pilot/builder to go the route needed to certify for E-LSA?

Not sure I understand the question. Under these circumstances, the RV-12 could NOT be certified as E-LSA. It would be certified as amateur-built. Advantages of amateur-built are that you can get the repairman's certificate just by proving you built the aircraft instead of having to pass the 16 hr. class required for the light-sport inspection certificate. There is one way for the -12 to be certified as E-LSA. If it is completed and certified before 1/31/2008, it could be certified under FAR 21.191(i)(1) as a grandfathered aircraft. Under this reg, it could be used for flight training until 1/31/2010.
Call me if you would like to discuss further. 972-784-7544 before 9pm CST.

The aspect of E-LSA versus amateur built experimental that seems to be most overlooked is in fact the 51% rule.

An E-LSA kit can be virtually complete, requiring only simple bolting together, if the manufacturer supplies it that way. Again, there must be an approved S-LSA version already certifies to do that.

If Van's doesn't certify the RV-12 as an S-LSA, it can only be sold as an amateur built kit, requiring 51% of the build to be done by the builder.

One thing I've noticed with many of the 'repeat offenders' is that they miss the building process and end up selling their newly completed plane to start another!

In light of the use of pulled rivets on the RV-12, are saying that the build time could be as low as 800 hrs. for a slow-build kit. Who knows how many fewer for a quick-build (49%) kit. Do we really need Van to supply a more complete kit than that? Plus there could be no modifications to the design.