Usable single-seater on 24 hp?

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pwood66889

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I remember the Eureka builder was a Wilf Stark, from Canada. He just seems to have pulled up stakes and disappeared. "...surely somebody knows" sounds logical, but remember D. B Cooper.
I was acquainted with a CA-2 project back in Oregon, and missed a chance to buy one about 5 years ago... mutter, mutter... Still have a file on it.
Stuff really decamps quickly in the flying world... :-(
 

Tiger Tim

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I wonder if the Eureka is the plane I remember seeing at the Toronto aviation show when I was a kid? There was some little single seater of unusual construction, I seem to remember it being wood longerons, foam filler between them, and very thin metal skin.
 

Victor Bravo

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Getting back to the original subject, there are also a few "legacy" designs and somewhat forgotten flying machines that did OK on 24HP. The Sky Pup has been mentioned, and I'd like to mention the old Mitchell Wing apparently flew well enough with a 20-25HP Zenoah engine. That's more modern of a design than the OP wants to discuss apparently, but it works reasonably well if flown in reasonable conditions.
 

BJC

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there are also a few "legacy" designs and somewhat forgotten flying machines that did OK on 24HP.
What passed as acceptable performance years ago probably would not be acceptable to most pilots today. Likewise, what passed as a typical pilot’s mass pre-WW II, is much less than what is typical today.

BJC
 

cluttonfred

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To be clear, while I opened with an idea to start the conversation, I welcome any ideas for new or existing designs that might work on modest industrial engine four-stroke power.

I do think that relatively heavy industrial engines and plus-size pilots make Part 103 challenging, though not impossible. It's just a delicate dance when the engine choice means more weight to carry on limited power but you can't have a design that's too clean, either, or you'll bust the speed limits. I would not rule out something because it meets Part 103, I am just not insisting on it.

The real key here is a usable aircraft that can carry at least 300 lb of pilot + baggage + fuel on a common industrial V-twin engine. That leaves room for everything from a "Sky Pup XL" putting around the pattern at 30 knots over a grass strip on a summer day to a "Quickie XL" zipping along at 100 knots on a cross country and everything in between.
 

blane.c

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AIRPLANE 24HP 1.png
AIRPLANE 24HP 2.jpg AIRPLANE 24HP 3.png AIRPLANE 24HP 4.jpg AIRPLANE 24HP 5.png AIRPLANE 24HP 6.jpg AIRPLANE 24HP 7.jpg AIRPLANE 24HP 8.jpg

It depends on how fast you want to fly on 24hp? The Sky Pup fly's well and is a slow flying aircraft, the lack of ailerons is beneficial in this regard, ailerons contributing more to excessive drag and yaw control issues than any real contribution to roll at the very slow speeds at which it fly's.

It appears you would like to fly faster than that by the looks of the shapes you really like. To scale one of those down to 24hp may require the cockpit to look a bit more "bulbous" in relation to the rest of the design?

jetson-animated-car.gif

It may be ok to "ride in the wind"?

LAS VENUS 15.png
 

Victor Bravo

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I welcome any ideas for new or existing designs that might work on modest industrial engine four-stroke power.

The real key here is a usable aircraft that can carry at least 300 lb of pilot + baggage + fuel on a common industrial V-twin engine. That leaves room for everything from a "Sky Pup XL" putting around the pattern at 30 knots over a grass strip on a summer day to a "Quickie XL" zipping along at 100 knots on a cross country and everything in between.
Other than it not looking like a WW1 machine, tell me why the Luciole is not the obvious answer to the original requirement. I had mentioned it early on in this thread, and I know you are very well aware of its existence and performance. The designer may even allow you the privilege of speaking with him in his native language, an honor which he would likely not bestow on many of us unwashed and insufferable Americans.
 

cluttonfred

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VB, Michel Colomban’s Luciole is a fantastic design, refined and well-proven, but it’s pretty tiny, the useful load is just over 100 kg, and construction is pretty finicky, so it’s not for everyone. I had in mind something even Erkki could fit in and anyone could build.

blane.c, happy to discuss but I’m not sure where you’re going with this.

Some quick numbers...

Rutan Quickie
18 hp Onan, 220 kg gross - 112 kg empty - 23 kg fuel = 85 kg (187 lb) pilot + incidentals

MC.30 Luciole
25 hp B&S, 200 kg gross - 97 kg empty weight - 21 kg fuel = 82 kg (181 lb) pilot + incidentals

PIK-26 Mini-Sytky
35 hp Citroen Visa, 250 kg gross - 144 kg empty weight - 20 kg fuel = 86 kg (190 lb) pilot + incidentals

SD-1 Minisport
33 hp B&S, 240 kg gross - 130 kg empty - 26 kg fuel = 84 kg (185 lb) pilot + incidentals

So, in practice, any of these designs is limited to pilots who are pretty close to the FAA standard 170 lb (77 kg) fully dressed and ready to fly. It seems to me that a design that had adequate performance with a larger load load (either a big and tall pilot or a pilot with some baggage) would be a welcome addition to the market.
 
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blane.c

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Going to your original statement 250lb pilot plus fuel 350lb empty weight and 600lb gross weight, something has to give?
10 gallons = 60lbs so additional 10% weight increase for fuel? 660lbs gross?
660lbs 24hp = 27.5lbs per hp. … So the pilot could lose 60lbs instead then 600lbs gross 24hp = 25lbs per hp. … that hardly sounds worth it, have a cookie.
74mph cruise at 75% power = 74mph with 18hp. And 35mph stall so 1.2 x 35 = 42mph best angle of climb so propeller pitched for the max 24hp at 42mph? Or propeller pitched for best cruise at 18hp and 74mph? Or with 640fpm climb as a goal 1.4 x 35 = 49mph best rate so pitch propeller for 24hp 49mph and try to get 640fpm?
 

blane.c

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It won't have "the sound" so you'll need a PA system playing a "proper" aircraft noise recording. You wouldn't have to play it all the time just when there are "witnesses".
 

cluttonfred

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blane.c, I think electrics option probably deserves their own thread.

I am not at all opposed to electric flight, in fact, I suspect it will be the norm within my lifetime, but right now there does not seem to be an off-the-shelf solution. Like may people, I suspect, I have been put off when dabbling in electric power by how complex it can be in term of power and battery management. The day that a manufacturer is able to offer a complete, bolt-in, ready-to-install system that you pick from a menu*** at a price comparable to IC engines, I and many others will be very interested.

***What I mean by this is being able to choose from a certain number of options for horsepower, propeller orientation (or fan), throttle type, instrumentation, power/battery management, and battery capacity and then just hook it all up rather than have to work it all out component by component.
 

blane.c

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VB, Michel Colomban’s Luciole is a fantastic design, refined and well-proven, but it’s pretty tiny, the useful load is just over 100 kg, and construction is pretty finicky, so it’s not for everyone. I had in mind something even Erkki could fit in and anyone could build.

blane.c, happy to discuss but I’m not sure where you’re going with this.

Some quick numbers...

Rutan Quickie
18 hp Onan, 220 kg gross - 112 kg empty - 23 kg fuel = 85 kg (187 lb) pilot + incidentals

MC.30 Luciole
25 hp B&S, 200 kg gross - 97 kg empty weight - 21 kg fuel = 82 kg (181 lb) pilot + incidentals

PIK-26 Mini-Sytky
35 hp Citroen Visa, 250 kg gross - 144 kg empty weight - 20 kg fuel = 86 kg (190 lb) pilot + incidentals

SD-1 Minisport
33 hp B&S, 240 kg gross - 130 kg empty - 26 kg fuel = 84 kg (185 lb) pilot + incidentals

So, in practice, any of these designs is limited to pilots who are pretty close to the FAA standard 170 lb (77 kg) fully dressed and ready to fly. It seems to me that a design that had adequate performance with a larger load load (either a big and tall pilot or a pilot with some baggage) would be a welcome addition to the market.
I agree these designs are limited to the 170lb pilot. Also when I flew my Champ, my first instructor and myself neither came close to 170lbs especially dressed properly for the weather. It was just ignored, and for the Champ it wasn't a problem. Some of these newer designs are more critical regards weight and structural sufficiency. I don't know what airplanes should be designed for other than 170lbs sure isn't it. It seems also that people forget to put clothes on when talking about weight, so a 200lb person with clothes including sensible shoes is well over 210lbs but realistically you need room for 260lbs at 3.8g loading then you are talking about something. Over that weight and a person needs a two place. 24hp is overly restrictive to carry that much passenger at any kind of speed because the weight of all the structure has increased too. You are back up to a VP-2 sized airplane which is really a 1 1/2 person plane and that is what you are talking about. In the time the VP-2 was being conceived the 1500cc was it, 50hp and 91ci. I believe you can make a 1 1/2 place airplane for less than 50hp. At some point you have to quit thinking hp with direct drive fixed prop four stroke engines and start thinking ci, there is no replacement for displacement under those requirements. Most accounts are that the VP-2 was not a stellar performer and that at 1040 gross weight so 1040/91 = 11.4lbs per cubic inch, so 600lbs x 11.4 = 52.6ci. Thinking not stellar performance with 52 cubic inches and 600lb gross. SD-1 max gross 533lbs 49ci = 10.8lbs per ci. So how many ci in the 24hp engine?
SD-1 PERFORMANCE CHART.png 49ci sd-1 49ci engine.png

The other option is a true motor glider, 1 1/2 person sized like a Xenos https://www.sonexaircraft.com/xenos/ except a lower priced lower powered better looking canard version.
The Fauvel with an electric motor would likely be attractive to a lot of younger people if it could be designed with a 1 1/2 sized person in mind. There are Halbach motors http://www.launchpnt.com/portfolio/transportation/halbach-electric-motor which are very efficient and expensive, the good electric motors like Dale Kramer used on his Lazair are not available to the general population any longer as the company has put efforts in a different direction.
 

blane.c

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blane.c, I think electrics option probably deserves their own thread.

I am not at all opposed to electric flight, in fact, I suspect it will be the norm within my lifetime, but right now there does not seem to be an off-the-shelf solution. Like may people, I suspect, I have been put off when dabbling in electric power by how complex it can be in term of power and battery management. The day that a manufacturer is able to offer a complete, bolt-in, ready-to-install system that you pick from a menu*** at a price comparable to IC engines, I and many others will be very interested.

***What I mean by this is being able to choose from a certain number of options for horsepower, propeller orientation (or fan), throttle type, instrumentation, power/battery management, and battery capacity and then just hook it all up rather than have to work it all out component by component.
That is a good idea.
 

cluttonfred

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For the record, the original VP-2 flew with an 1835cc VW and in subsequent testing was upgraded to 2070cc and finally 2180cc. Performance was improved with the 2180 but not as much as you might think, climb at full gross was 400 fpm with the smallest engine and 450 fpm with the largest. That seems to be more of an indictment of the VW engine than the airframe in my mind. VP-2s have been flown with A-65s with improved performance, but the added weight made them single-seaters in practice. That's why I am attracted to the idea of a light Suzuki 3-cylinder with redrive for a VP-2....

Any aircraft designed for performance on relatively low power usually starts to look pretty glider-like. 24 hp is probably too low for the mission I described, something like a 33-37 hp Briggs & Stratton Vanguard with Ace redrive probably makes more sense. With that much power available, 300 kg gross weight and 125 kg useful load seems very doable, which would allow for substantially heavier pilots. Not for the first time, I think it would be great fun if someone were to offer a small engine that range and then sponsor competitions (racing, efficiency, all-around performance) requiring absolutely stock, unmodified engines.
 
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