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Kitplanes Magazine's Kate O'Conner's take on buying a used Sonex:

https://www.kitplanes.com/buying-used-sonex-waiex/

From the article:

Similarly, the aircraft’s gross weight should be below 1150 pounds if equipped with an engine producing 100 hp or greater or 1100 pounds if the installed engine produces less than 100 hp. A Sonex with a licensed gross weight above those thresholds will be disqualified from the Light Sport category.

Is the second sentence actually true? That would imply that too low of a power loading would disqualify an aircraft from being an LSA. That doesn't make sense.

Everything I have read on light sport category lists 1320lb MTOW and I believe 1420 allowing for floats on a seaplane. Outside of that you have speed requirements both upper and lower (stall). I have never seen anything listing an engine size or hp rating in the wording. In other words you could put a 5000 hp engine in a plane that met the above reqs and it would still be LSA. Likewise if you put a 15 hp engine in the same plane it would also be LSA. In this instance we could take an 80hp sonex and list it at 1320 MTOW and it would still be LSA. It would be way out of the design parameters set forth by Sonex, but it would still fit the regs. I would hate to test that set up though. We all know there are limits to what will fit within those reqs and actually work and be safe. I could be wrong about this but that has been the information I have found in the past so unless something has changed I would expect it to still be current. There is some talk about the weight limit going up on LSA but I have not seen anything yet.
Mark WHiddon

GraemeSmith wrote:Kitplanes Magazine's Kate O'Conner's take on buying a used Sonex:

https://www.kitplanes.com/buying-used-sonex-waiex/

Unfortunate that the Xenos or OneX aren't mentioned at all. Almost like they don't exist.

One of the things that moves an airplane out of LSA is the stall speed. The FAA uses math to check this. So a stock Sonex that is certified heavier may not meet the LSA stall speed. Its just math ;)

For example, the Onex needs the full length wing tips to meet the stall requirements at gross weight. If the FAA sees the standard gross of 950 and it has the short wingtips, they automatically know its NOT LSA compliant.

Bryan Cotton wrote:From the article:

Similarly, the aircraft’s gross weight should be below 1150 pounds if equipped with an engine producing 100 hp or greater or 1100 pounds if the installed engine produces less than 100 hp. A Sonex with a licensed gross weight above those thresholds will be disqualified from the Light Sport category.

Is the second sentence actually true? That would imply that too low of a power loading would disqualify an aircraft from being an LSA. That doesn't make sense.

Sonex has always said that the gross weight should be based on engine power as a matter of safety.

The only criteria for LSA compliance is gross weight, stall speed, and top speed at max continuous power. The author is incorrect.

I seem to recall that there is an issue of wing loading per horsepower that the factory posted about that is part of the LSA standard. It was in a discussion about why a 1,200lb "apparently legal" Sonex LSA is perhaps not if it only has 80hp up front. Wish I could find that post again. It was either a "legality" or a "consideration".

Like radfordc says, light Sport Aircraft fit very specific requirements. A 1200 pound "apparently legal" LSA may not fit one of the criteria such as stall speed. Power loading has nothing to do with it.

Gentlemen - remember you are not just communicating with aviators in the USA.

Other jurisdictions have very different views/laws on what constitutes a light sport aircraft (note the lack of capitals).

For example: There is no air speed restriction on such aircraft in Australia (registered under Recreational Aircraft Australia/RAA , with general aviation /GA has different rule again) - just a max take off weight (600kg) Stall 45 knots, Max 2 persons, etc etc . There are other rules and some minor exception but this is pretty much the core.

Hi Graeme

Haven’t found the post either, but I remember it from pretty far back. LSA rules stipulate MGTOW, maximum gross stall speed (which I seem to recall is in clean configuration), and max indicated airspeed at sea level.

The factory added reasons why gross weight should not be increased. These included power loading, structural loading, structural fatigue, and perhaps more.