Switch from E-AB to LSA?

[Frank Giger]

Of course we're agreeing with each other in different ways, Ron.

But it all comes down to when the aircraft was signed off on. For my gross weight I slapped a happy number down, one that I won't actually ever reach (or at least hope never to).

And all the V speeds are a big unknown at Pink Slip Time. There are some educated guesses, but they're all blank at hour zero.

My point was that once it's established, one shouldn't change the gross weight limits without running into a flag from the FAA refs. Heck, I know a guy with a FlightDesign CTLS that has been known to take off with full fuel tanks, two passengers, and the baggage limit and survived. It's almost like the FlightDesign folks stuck the number 1320 out there just to make the LSA requirements! And "cruise" is a fickle number to begin with. Va and "best cruise" for fuel efficiency are related, but only casually so. The rules for LSA compliant aircraft only say "cruise speed" and so it's firmly in murky water territory.

In many ways, my little Bebe is the reason for LSA rules. She's a big fat ultralight with a 12 gallon fuel tank.

[bflynn]

The Zodiac CH650 is legitimately light sport - depending on the engine, somewhere between 625 to 730 lbs empty weight, 30 gallon tanks with larger tank upgrade, plenty of useful load. The only variable factor is the speed. It can go 140 or it can go 120 depending on the prop.

It's a moot point. I'm on the verge of pulling the trigger on building but it will be a few years before I put a prop on it. Medical reform will be long past by then. If it passes I can build it fast, if not then I built it E-AB to LSA specs. If it passes later, I can change it later. About the only extra thing I have to do is add lights and even that is months to a year down the road.

Of course I've been on the verge of pulling the trigger for a while now.

[dljosephson]

Simple question - is it possible? I've searched and cannot find anything that confirms it, but can't find anything that says it's impossible either.

It might help to give a specific scenario. The kit is a Zenith CH-650, 2 seats, ~650lbs empty weight. My understanding is that the kit can be built as an E-AB and reach speeds faster than 120 kts. OR the prop can be changed out to trade speed for climb and the speed will be truly limited to 120 kts and the aircraft will meet LSA standards.

You might want to do some more research. The CH650 is a great airplane, but it would be really tricky to build one that weighs 650 pounds, and I doubt that you could reach 120 ktas in continuous full power level flight at sea level (the regs say nothing about cruise) with any practical engine. You're building the engine too, right? You get to decide what the maximum continuous power is. Frank Giger's comments are correct. Who's to say it goes more than 120?

[martymayes]

Of course I've been on the verge of pulling the trigger for a while now.

At least you're not trigger happy....:-)

[earldowns]

The Vc of the CH650 is 108 kts IAS. The Zenith definition of Vc is “The Maximum Structural Cruising Speed that should not be exceeded except in smooth air and only with caution.” Why are we discussing an IAS cruise of over 120 kts IAS?

[dclaxon]

My understanding is that no matter how fast the aircraft may be capable of going, if the builder writes into the operating limitations that the maximum cruise is 120kts, then the limits is 120kts. That may or may not fall within the intent of the law, but I'm reasonably certain that there is a large number of LSAs that have been done that way.

And as for how it's registered, given the limitations put on LSAs I see absolutely no benefit of registering a homebuilt as an LSA. And it makes no difference in who can fly it, if it's registered LSA, E-AB, or even a real certificated aircraft, if its weight, speed, complexity, etc fall within the Light Sport definition, it can be flown by a Sport Pilot.

I don't claim to be an expert, and I may be wrong about tis, but that is the way I understand it.

Dave

[rwanttaja]

My understanding is that no matter how fast the aircraft may be capable of going, if the builder writes into the operating limitations that the maximum cruise is 120kts, then the limits is 120kts. That may or may not fall within the intent of the law, but I'm reasonably certain that there is a large number of LSAs that have been done that way.

Aircraft certified as Special Light Sport (SLSAs) are required to gain FAA approval, and this would include showing supporting documentation that the aircraft meets the performance limits. Experimental Light Sport Aircraft (ELSAs), *at the time the type received FAA approval* must also be able to prove compliance. This FAA approval process is simplified over Part 23 aircraft, but it does still exist.

Once an owner gets his or her mitts on an ELSA, there's nothing stopping them from adding streamlining, changing prop pitch, putting on a bigger engine, etc. that would allow exceeding the 120 knot limit. Technically, the plane would not be in compliance, but in reality, the FAA is unlikely to check.

And as for how it's registered, given the limitations put on LSAs I see absolutely no benefit of registering a homebuilt as an LSA. And it makes no difference in who can fly it, if it's registered LSA, E-AB, or even a real certificated aircraft, if its weight, speed, complexity, etc fall within the Light Sport definition, it can be flown by a Sport Pilot.

You can only register a kit as Experimental Amateur-Built (EAB) if it meets the 51% rule, and you can only register a kit as a Light Sport if it complies exactly with the aircraft the manufacturer used to gain SLSA certification. These two sets don't necessarily overlap, as kits for Experimental Light Sport Aircraft are allowed to be in a greater state of completion and thus may not comply with the 51% rule.

But there are aircraft that do; the RV-12 is one. Given my druthers, unless there were serious modifications I wanted to build in, I'd build one as ELSA. It's no difference to the original builder, since he or she can get a Repairman Certificate and perform the condition inspections on the EAB.

But it comes into play at sales time. The guy who buys the EAB RV-12 will have to either talk the original builder into continuing to perform the condition inspections, or hire an A&P. The person who buys the ELSA RV-12 can take a 16-hour course and can then do the inspections.

Ron Wanttaja