A record empty/MTOW ratio?

ploucandco wrote:

Rotax 912ULS will give you 73.5kW (98HP) at 5800RPM for 5 min and 69kW (92HP) at 5500RPM max continuous. Consumption at max continuous is 25L/h.

Thanks for correcting me!
So a 100hp normally aspirated Continental has an 8% more max continuous power then a 100hp normally aspirated Rotax.

LeSving wrote:

All carbon, double fowler flaps and so on.

If you would compare empty weight of Colomban MC100 and MCR Sportster 80, which are from aerodynamical point of view identical airplanes, you would find that the first one, which is built from duraluminium sheets is actually lighter then the second one which is “all carbon”.
An airplane comparable with “ONE” in terms of useful load and power plant is Jodel 1050. Has no flaps at all, perfect grass strip and even ski capability. My guess is that the “ONE” is much more comfortable though.

Robin_253 wrote:

So a 100hp normally aspirated Continental has an 8% more max continuous power then a 100hp normally aspirated Rotax.

No, the 912 iS has 98 hp continous, 2% Also, the one we have to tow glider has “big bore” mod, so it has 120 HP max, and whatever continuous max we dare to run A Rotax is not a Rotax, there are lots of variants, and lots of mods that can be done to them (big bore, EFI, EI, EI+EFI, FADEC, turbo).

Robin_253 wrote:

you would find that the first one, which is built from duraluminium sheets is actually lighter then the second one which is “all carbon”.

Maybe, I haven’t really studied them, but carbon is stronger and more rigid for the same weight. The Atec 2000 is delivered in two variants. Both have carbon composite fuselage. The Zephyr has a wooden/fabric wing, while the Faeta has a carbon wing. The Faeta has slightly more max VNE (but really not enough to mention), but +5g instead of +4g. The weight is roughly the same, I think the Faeta is 1-2 kg heavier, but has more comfortable upholstery, better seats and so on. What is gained with carbon on terms of weight is usually taken back again with more “luxury”, but the added strength and rigidity is still there.

The One has 415 kg empty weight and 750 kg MTOW. This is about the same ratio a RV-10, 4 people and cruises at 175 knots (but drinks a whole lot more fuel ) Still, this is less than the average Sonex, and it can do +6 g and is fully aerobatic. The MCR 4s is in a league of it’s own though.

It’s good we have all these different planes to chose from, one for every person.

There are some utility SEP which boast Useful load>Empty mass:

Cherokee 235
Cherokee Six-260
Early Cessna 206
Ag planes

They may be of the stripped marketing brochure variety but I believe having this ratio was part of the selling point.

Our SAN Jodel DR1050 had an actual mass of 410.6kg without spats, and an AUW of 750kg. (Weighed at about age 45 at C of A, now Annex 2)
Cruise at over 110kts.
The one-piece wing is off and being recovered – transported on a low-loader artic. Mass will be different when reweighed after reassembly.

LeSving wrote:

The are many aircraft with MTOW 750 kg and a Rotax already flying, Aquila comes to mind.

Indeed. But the Aquila A211, which I am learning to fly on, has an empty weight of 506 kg and MTOW of 750 kg, so the ratio is much worse than in the example posted by Jan. Actually, with me weighting 100 kg and my FI weighting around 60 kg we can barely fill the tanks full without exceeding MTOW :(