Continued growth in the USA for LSA/homebuilts etc

I believe the E-AB-only data (412 planes) includes those US Experimental Amateur Built aircraft that also fit into the LSA category: “EAB-only separates the ELSA out of the strictly homebuilt segment”. That means of the 728 LSAs, 316 were factory built.

Meanwhile the most recent data I can find, for 2019, shows about 1200 newly registered E-AB aircraft in total for the year, including all types and categories of planes including both LSA and larger/faster types. 316 factory built LSAs would add to that number to generate a total number of ‘non-certified’ new aircraft registrations, which if I’m adding it up right is something over 1500. Factory built LSA is thereby about 20% (300/1500) of uncertified annual production, and that obviously represents a relatively small segment of US light aircraft commerce including both the other 80% of uncertified aircraft produced, new certified light aircraft produced and activity/sales/maintenance of existing light aircraft of all types and categories.

interestingly enough my home market is well and alive… 188 registered homebuilts (of which some could be LSAs if that category was alive here), and there are another 150+ in the works. 9 first flights in 2022 alone, and this for a country as minute as it is

People are generally moving away from the thirsty certified dinosaurs to equally, or more capable, homebuilts or ULs in Europe too.

“thirsty certified dinosaurs”
The big saving is from “uncertified”. We were struggling to afford a certified CAA Jodel, until EASA came along, and put us on Annex2. Without increasing charges, despite fuel increases, we quickly (~10 years) built up a large maintenance fund – to more than the sale value of the aircraft.

Maoraigh wrote:

“thirsty certified dinosaurs”
The big saving is from “uncertified”. We were struggling to afford a certified CAA Jodel, until EASA came along, and put us on Annex2. Without increasing charges, despite fuel increases, we quickly (~10 years) built up a large maintenance fund – to more than the sale value of the aircraft.

Uncertified? Sure, brings cost savings but the word “thirsty” is at least as important for me – moving from Conti onto Rotax power means currently a saving of around 5k per annum in fuel costs alone, comparing like for like cruising speeds and 100 hours a year. Let that sink in. €50 an HOUR savings.

The “dinosaur” bit is nearly as important as you get a warm fuzzy feeling knowing that anybody talking about GA use of leaded fuels “killing small babies and puppy dogs” doesn’t apply to you as your machine is a fuel injected modern piece of technology. When I tell people the fuel consumption of my steed is typically better than that of a typical small family car, they suddenly sit up and take note.

€50 an HOUR savings.

What were the cockpit volumes of the two planes?

I thought @Dan s comparison of a Lycoming O-360 powered RV and a Rotax powered ULM, both level at 100 kts was interesting: same fuel burn. The difference is that the RV can also do 180 kts, climb at 2000 fpm and do aerobatics. I imagine the interior volumes of those two planes would be similar, and the payloads likewise although the RV might have a bit more useful load.

The type of piston engine has little to do with aircraft efficiency except in extreme corner cases, and my Lycoming is STC’d for unleaded fuel. Turbo diesels are a bit more efficient but very complicated in relation to their power output, old Franklins tend to be inefficient due to poor fuel distribution, and so on.

Certified versus uncertified also has little to do with aircraft efficiency, it’s just that certified planes tend to have (much) higher payloads and (often) more room. There isn’t a huge market for factory built certified planes with little room or carrying capacity, notwithstanding that I happen to own and fly one. Only about 316 quasi-certified LSAs fitting that description were sold in the US last year, and almost none certified. Few people want to buy them, so mostly if you want one you build it yourself.

Silvaire wrote:

I thought @Dan s comparison of a Lycoming O-360 powered RV and a Rotax powered ULM, both level at 100 kts was interesting: same fuel burn.

I had similar comparisons over times, only a little different reference. If you go for fuel per mile, the consumption is surprisingly shallow in increase with speed. Yes, clean sheet wing profiles do a little for efficiency, but for cost of more critical tendencies. Going 95 knots on 7 GPH in a C172 or 150 knots on 13 GPH in a Beech or 200 knots on 18 GPH in a SR22 is a only a 13-16 MPG spread. In the end aviation is one of the arts which has been energy optimised from start, as that was necessary to lift off with small engines anyways.

Peter wrote:

€50 an HOUR savings.
What were the cockpit volumes of the two planes?

In terms of width, maybe half an inch narrower in the new plane. In terms of rear seats, only suitable for kids but as I only ever flew once with all seats full and maybe 3 times with more than one other on board, negligible. In terms of load carrying, similar.

edited to add: in terms of height, there is a marked difference of an inch or two of headspace but as I fit comfortably in the new machine, I don’t miss that headspace.

MichaLSA wrote:

Going 95 knots on 7 GPH in a C172 or 150 knots on 13 GPH in a Beech or 200 knots on 18 GPH in a SR22 is a only a 13-16 MPG spread. In the end aviation is one of the arts which has been energy optimised from start, as that was necessary to lift off with small engines anyways.

I did a calculation for my current aircraft. At MCP it’s returning 25mpg US or 30mpg Imperial. At normal cruise it’s 31mpg US or 37mpg Imperial – this just shows how efficient the 912iS engine truly is. Either that, or it just shows how much efficiency could be gained by upgrading Lyco / Conti engines with electronic fuel injection, electronic ignition controls etc….

I did a calculation for my current aircraft. At MCP it’s returning 25mpg US or 30mpg Imperial. At normal cruise it’s 31mpg US or 37mpg Imperial – this just shows how efficient the 912iS engine truly is.

This has very little to do with the engine except that the Rotax in basic form is light, like the rest of the plane. EFI versus mechanical injection makes almost no difference, electronic ignition is slightly useful at very high altitude, when you run in cruise at low MP and high RPM, which with variable timing allows more spark advance. Electronic ignition is therefore good on a Lycoming, but not earth shakingly so.

Otherwise, going slower in a smaller, lighter plane saves fuel:

Slower cuts fuel consumption in mpg by roughly the square of the speed ratio, assuming the planes are both traveling at their design cruising speed.

Smaller and lighter reduces power and fuel consumption to travel at a given speed: smaller cuts parasite drag, lighter cuts induced drag.

The only real issue with air cooled engine fuel efficiency is in initial climb, when they are run rich. If it’s a 150 HP engine that means maybe 2 gph or 0.033 gpm wasted fuel for cooling when at full throttle, full rich. If the climb is at 800 fpm to 7500 feet from a 500 ft airport, that’s 0.288 gallons of fuel wasted to provide cooling. In my area that’s $1.44 on that flight, compared with a nominal fuel burn of $41 per hour on Avgas once you’re level.