RV-12 EAB Gross Weight

JKevin · #1 01-04-2020, 05:48 AM

Looking at an EAB RV-12 with an alternate engine which appears to be a well thought out package. The builder has set a GW of 1420 pounds.

I know that the standard LSA wt is somewhat arbitrary at 1320, but also that the RV-12 was designed to this GW.

Any thoughts on the structural implications of the builder-increased GW?

Larco · #2 01-04-2020, 07:21 AM

Looks like unless it is a seaplane the GW of 1420 pushes it out of the LSA category?

N941WR · #3 01-04-2020, 07:46 AM

The RV-12 is built much lighter than the other RV's, I'm not sure how well it takes to an inflated GW.

Bummer he set the GW above 1320 as it can no longer be flown as an LSA, even if structurally it is OK.

Fo example, the Bearhawk LSA is designed for a 1500 lb GW but if built light and certified with a GW of 1320, it can be flown as an LSA; however, if certified at 1500 lbs, it cannot be flown as an LSA, even if the max weight is limited to 1320.

Piper J3 · #4 01-04-2020, 07:47 AM

I would guess heavier engine so builder arbitrarily increased GW to allow a useful load ? not a good idea. Original designer (Van?s) or a really good aeronautical engineer with structural and flutter testing knowledge might be able to ?weigh in?.

Bad things can happen?

JKevin · #5 01-04-2020, 08:28 AM

Some more details about the plane...

I know that from a certification / legal standpoint this plane can never qualify as an LSA...More concerned about structure with regards to weight.

Not interested in pushing the TAS / Vne envelope.

I don't know that the engine is *much* heavier, maybe 20 pounds... it's a 912UL with an aftermarket turbo / intercooler and airmaster constant speed propeller. So clearly not ELSA nor LSA.

Kyle Boatright · #6 01-04-2020, 08:38 AM

One thought would be to fly it at a max of 1320. Other than not overspeeding it, you'd be good.

As far as engineering goes, Van's probably won't stray from the 1320 number. Given the weight restrictions on LSA, I'm sure the -12 was engineered to a pretty fine line, meaning it is fine at 1320, but they didn't build in excess margin above that because of the negative impact it would have had for airplanes registered as E/LSA's or LSA's.

NinerBikes · #7 01-04-2020, 08:47 AM

Quote:

Originally Posted by JKevin

Some more details about the plane...

I know that from a certification / legal standpoint this plane can never qualify as an LSA...More concerned about structure with regards to weight.

Not interested in pushing the TAS / Vne envelope.

I don't know that the engine is *much* heavier, maybe 20 pounds... it's a 912UL with an aftermarket turbo / intercooler and airmaster constant speed propeller. So clearly not ELSA nor LSA.

The 912UL is 80 hp rated, with some known issues of earlier models fretting the cases. I would be very leery to turbocharge the 80 hp motor version of this.

I'd be more inclined to just run a stock normally aspirated 100 HP 912 ULS version on 91 octane car gas.

I guess I am not smart enough to know how the builder got the weight increase in the design by building it E-AB, since Van's designed the whole plane exactly around the US standard of 1320 # Gross to meet the E-LSA FAA standard.

Your money, your choice, your life, while up in the air.

I've owned enough German and Austrian built and designed motors in cars and Personal watercraft, to know that they don't take well or last very long when you start modifying them to make more HP and torque. You very quickly find the next weakest link in the design. These aren't American engineered and built V-8's from the 60's and 70's when we had real premium gas and an abundance of engineering safety margins built in to the designs. Aircraft engines are built and run a lot closer to "the edge" hence the 2000 hour TBO, on the newer 912ULS motors.

Someone built this with a used, cheap 912 UL motor.

The other factor is that you will need a paid AP to do your annuals, every year on this, unless you are an AP yourself.

crashley · #8 01-05-2020, 01:53 AM

I would be very wary of the weight and balance
20lb extra up front, how did they compensate for that counterweights in the rear etc

joe gremlin · #9 01-05-2020, 11:09 AM

Quote:

Originally Posted by JKevin

I don't know that the engine is *much* heavier, maybe 20 pounds... it's a 912UL with an aftermarket turbo / intercooler and airmaster constant speed propeller. So clearly not ELSA nor LSA.

All other comments aside, any idea what kind of performance the plane sees with that setup?

NinerBikes · #10 01-05-2020, 11:40 AM

Here is a 912 UL turbo kit that give you 120 HP for a maximum of 2 minutes. And TBO is down to 1500 hrs.

https://www.912turbokit.com/fly-120hp

The rest of the time, it's much lower rpm's, and much lower HP, while still running boost. About the same as the 100 HP Mogas drinking 912 ULS.

Unless you take off at 6 to 7000 ft or more ASL, all the time... think living near a Rocky Mountain state, I'm lost on any attributes, for all the additional headaches it entails. To me, the risk doesn't warrant the rewards. YMMV, I'm pretty conservative on even wanting to hot rod plane engines that keep you up in the air.

Yesterday, Locally, a Thunder Mustang P51 went down with a lost motor, 3 miles from my home, out of VNY. 1 lost soul on board, the pilot. Engine failure, smoke in cab, he couldn't see out. Based on witnesses accounts, he appeared to have stalled and fell straight in, nose first. Most of these have hot V8 motors in them. https://losangeles.cbslocal.com/2020...and-14-freeway