spec list of efficient light planes

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patrickrio

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The Aeronca C2 appears to fit the criteria. It's an amazingly efficient machine.
I am having trouble finding specs for the 26HP engine. the specs say 26-30HP sometimes but quote the speeds for the 30HP or the 36HP. Almost none were built with 26hp and most had either 30HP or 36HP.

I found one spec sheet that might be at 26hp that quotes a top level speed of 75mph but the climb rate is very low. I think this is just a little heavy at 406lbs empty 700lbs gross for 26hp.
 
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n3puppy

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I am having trouble finding specs for the 26HP engine. the specs say 26-30HP sometimes but quote the speeds for the 30HP or the 36HP. Almost none were built with 26hp and most had either 30HP or 36HP.

I found one spec sheet that might be at 26hp that quotes a top level speed of 75mph but the climb rate is very low. I think this is just a little heavy at 406lbs empty 700lbs gross for 26hp.
Plans for the Le Pelican may still be available. Pretty much a modern version of the 30's Aeronca C2 Did ok with18Hp With target 26hp - should easily break your 63mph.

Engine: Briggs & Stratton, 18 hp at 3600 rpm
Empty weight 210lb, 95kg
Max take-off weight 450lb, 204kg
Payload 240lb, 109 kg
Max level speed 60 mph, 97 kph
Max cruising speed 55 mph, 88 kph
Wing span 37.0ft, 11.28m
Total wing area 140 sq.ft, 13.0 sq.m
Stalling speed 26 mph, 42 kph
Max climb rate at sea level 500 ft/min, 2.5 m/s
Min sink rate 250 ft/min at 30 mph, 1.3 in/s at 48 kph
Best glide ratio with power off 13/1 at 35 mph, 56kph
Take-off distance 150ft, 45m
Range at average cruising speed 104 mile,

Found the C-2 FAA type certificate - Also listed as approved LSA plane
26hp given for engine
Three weights given - 675 as C-2 standard so guessing at least that would be 26hp model

3E673054-160D-4FFD-BBD4-2F5953FB3F8E.jpeg
 
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Flash

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Can you be more specific about the problems with the KFM engine?
The KFM supplied with the kit was the 22/24 hp direct drive. It had enough power,and ran well, but everyone I encountered had lost at least one prop in flight. One individual in MN lost 4. There just wasn't a proper way to securely attach the wooden prop. I was held on with just 4 small (AN4 if I remember correctly and AN365 nuts) bolts and nuts. The KFM engines with the belt re-drives didn't have this problem. Of course the re-drive version won't have work on the motor glider Moni. Obviously a vibration issue. A lot of fixes were tried but I'm not sure if anyone ever solved the problem. Mine never failed, but I didn't push it, replaced the hardware after every flight and only made short flights within gliding distance of a runway, and never put that many hours on it.

I've seen a few over the years re-engined with Rotax 503s and a few others. I'm sure they worked out OK, they just didn't fit into that small streamlined cowling. It was a neat little airplane. I guess this what happens when you design an airplane around one specific engine and there is a resulting problem. By the way, reportedly the engines would run just fine in the air without a prop, but it wasn't much use without it (it did keep all the needles moving on the gauges).

I saw an electric conversion at OSH about ten years ago that looked like the perfect solution. But the price for the batteries, motor, etc was over 15K-20K. Maybe it would be less today.
 

patrickrio

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Found it here -
https://www.aeroncamuseum.org
Have to sign up to get access - this TC was free membership. Other stuff like operation instructions require paid membership.

View attachment 109377
so no speed information is available in the specs at this location. Still not enough info to include in my list I think. I have included the pelican which is an ultralight weight aircraft loosely based on the C-2
 

patrickrio

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The KFM supplied with the kit was the 22/24 hp direct drive. It had enough power,and ran well, but everyone I encountered had lost at least one prop in flight. One individual in MN lost 4. There just wasn't a proper way to securely attach the wooden prop. I was held on with just 4 small (AN4 if I remember correctly and AN365 nuts) bolts and nuts. The KFM engines with the belt re-drives didn't have this problem. Of course the re-drive version won't have work on the motor glider Moni. Obviously a vibration issue. A lot of fixes were tried but I'm not sure if anyone ever solved the problem. Mine never failed, but I didn't push it, replaced the hardware after every flight and only made short flights within gliding distance of a runway, and never put that many hours on it.

I've seen a few over the years re-engined with Rotax 503s and a few others. I'm sure they worked out OK, they just didn't fit into that small streamlined cowling. It was a neat little airplane. I guess this what happens when you design an airplane around one specific engine and there is a resulting problem. By the way, reportedly the engines would run just fine in the air without a prop, but it wasn't much use without it (it did keep all the needles moving on the gauges).

I saw an electric conversion at OSH about ten years ago that looked like the perfect solution. But the price for the batteries, motor, etc was over 15K-20K. Maybe it would be less today.
I have been following the Moni Electric that has the zero motorcycle guts in it... the guy did a Earthstar Thundergull with Zero guts previously. If he ever posts specs, I would include that plane in the list also.
 

patrickrio

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I have highlighted in yellow the aircraft that only have zero to two known examples flying as they are mostly at the design and prototype stage really, although some fly/flew nicely.

I have also highlighted in green the ones that have or once had plans available for building from scratch. I think I have this right, but if I am incorrect anywhere, please let me know.

I like these but there seem to be very few efficient ultralights you can build from plans. I would love to find more. Here is the new list:
light planes capture new.JPG
 
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henryk

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Gregory Perkins

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There are many contradictions in this thread but the biggest is using the word "ultralights" as
their design objective was to fly slower than your 103max speed with a focus on the 103 minimum stall speed. I am not sure if ANY of the hundreds of ultralights would exceed 63mph on 26hp and still stall at the 26? mph requirement. Only the ones that cheated on the stall could fly 63 or faster. I doubt the Vampire could meet the stall minimum. There is one UL design that stands out to me at 185 pound empty weight that caused a ruckus at SunFun because during the UL exibition, it could not fly in a circuit without having to pass all the other ULs. Uniquely it was an aluminum tubed cantilever winged pusher. I am having a little trouble
figuring out which exact model and make engine put out 26hp. Are you thinking the Cuyunas sp? were 26hp or more ? What about the Rotax 277? Normally thought of as 28hp. I can only think that the Mitchelwing with a canopy might meet
the stall speed and also do 63 on 26hp. Maybe the Invader ? ? Turner Mariah? PeeWee, Penetrator, Wanderer, Maya, Opal Winton, PDQ, Aerosport Rail, GoldWing, Falcon, Cloud Dancer, Dormoy Bathtub, English Electric Wren, X-14, FLEA, Powered ATOS ? ? ?Eclipse-flyover.jpg
 

TFF

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The list needs to be put in groups. Some planes are for records and are not capable of normal use. Some are gliders; some are true 103 ULs. Some are for low time pilots and some are for better than average. All fly better with another ten horsepower.
 

patrickrio

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The title of the thread is "efficient light planes."

Because the available specs are often sparse, I defined "efficient light planes" as planes that can fly at the max level speed limit of far103 ultralights or faster on 26 hp (power of medium block vanguard twin approximately) or less. For specs you only need a max level speed or something close, and to know the engine hp and you can tell if the plane qualifies. The only far103 ultralights on the list are ones that "push the envelope" of far103 and might qualify under drag, HP and wing area rules outlined in 103-7. There are many airplanes that DEFINATELY do not qualify as far103 ultralights on the list.

This is obviously not a perfect definition and is pretty arbitrary in it's cut off. BUT you almost always have those two stats available for comparison even if many others are missing.

And the list ends up showing a variety of ways that engineers/builders have gone about getting high efficiency out of low power in small one person aircraft, which was my goal.

I did offer to split the list into groups and even make different posts, but it was pointed out that this is a pretty small niche of interest, so splitting it would be a waste of time.

So it remains in one list with color coding to highlight some important differences.

If you want further color coding, let me know what differences you want highlighted... Maybe a color for "Only has onboard power/energy sufficient for self launch and limited land out protection of a glider" might be one. "usable by low time pilots" might be another. "difficult/dangerous flight characteristics requiring advanced pilot capability" might be a further color. "actually fly's without tail number under far103" might be another....

Let me know what you think is useful and I will color code it in the list.
 
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Niels

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Aug 15, 2019
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The KFM supplied with the kit was the 22/24 hp direct drive. It had enough power,and ran well, but everyone I encountered had lost at least one prop in flight. One individual in MN lost 4. There just wasn't a proper way to securely attach the wooden prop. I was held on with just 4 small (AN4 if I remember correctly and AN365 nuts) bolts and nuts. The KFM engines with the belt re-drives didn't have this problem. Of course the re-drive version won't have work on the motor glider Moni. Obviously a vibration issue. A lot of fixes were tried but I'm not sure if anyone ever solved the problem. Mine never failed, but I didn't push it, replaced the hardware after every flight and only made short flights within gliding distance of a runway, and never put that many hours on it.

I've seen a few over the years re-engined with Rotax 503s and a few others. I'm sure they worked out OK, they just didn't fit into that small streamlined cowling. It was a neat little airplane. I guess this what happens when you design an airplane around one specific engine and there is a resulting problem. By the way, reportedly the engines would run just fine in the air without a prop, but it wasn't much use without it (it did keep all the needles moving on the gauges).

I saw an electric conversion at OSH about ten years ago that looked like the perfect solution. But the price for the batteries, motor, etc was over 15K-20K. Maybe it would be less today.
It is interesting because an opposed cylinder two stroke is just as bad mannered torque variationswise as a single cylinder two stroke or an opposed two cylinder four stroke.
I read once that Van Grunsven had to tighten propeller bolts after smelling burnt wood on his way to Oskosh .
Fourcylinder fourstroke and wooden prop.
Mating wood and metal has always been a risk affair.
One solution is maybe to double the diameter of the combat area and use more bolts.Was that one of the remedies tried?
 
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