VP-21A Single Seat / Yankee Luciole

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Vigilant1

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The only way of getting a good $/hp small engine is by using as many (or all) mass-produced components as suitable. That's why the Corvair, VW and 1/2 VW are still around today.
Indeed. And if "somebody" (ahem) wants 40 HP at less than about 90 lbs but rejects 2 strokes and the venerable 1/2 VW, then we probably need to get a third mortgage and be prepared to run a paramotor at 9000 rpm.

If someone were to go with a bit longer wingspan and keep weight and clean aerodynamics, I'm pretty sure 30hp will provide the requested climb performance and then less expensive mass-produced, (relatively) lightweight industrial engines become an option.
 

Vigilant1

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246 pounds? No way, that's almost 1/8 of a ton. Google says 197.9 pounds.
I have no trouble believing 5% of US males weigh 246 lbs because I seem to be seated next to one on about 50 percent of my commercial flights.

The oft-cited lower numbers are typically derived from US Army statistics, and typically from many years ago. The same figures show that the average US male weighs 171 lbs, and that obviously doesn't represent the US population. The folks that show up at a US Army induction center aren't representative of the US population: They are younger, weigh less, and are in better shape.
Here's the source of the 246 lb figure:
The Evolution of Anthropometrics and User Control

Here's a calculator. Enter your sex and weight and find your percentile in the US population (2015-2016 data).
Weight Percentile Calculator for Men and Women in the United States
197.9 lbs = 57 percentile US male.
The median weight of a US male is 190 lbs.

"Supersize me," indeed.
 
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Bigshu

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5. Full length narrow chord ailerons to lighten the flight loads and remove the cables from the wing internals so that the wing could be easily folded.
6. Hollow hot wire cut foam ‘D’ wing LE with carbon cloth covering (give the wing torsional strength.
I like the other suggestions, but these are awesome. The full length narrow chord ailerons could be used like the flaperons on the Taylor Mini-IMP and RV12. On the MI, you can reflex them to get higher cruise speed. The cut foam and CF leading edge for wing strength/rigidity is great, but does it move the project out of "hey, I could do that!" range?
Regarding your point two, I'm a fan of all flying tails, so maybe a single piece stabilator would be lighter and just as effective.
 

TFF

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I don’t think a new airplane design is really necessary. There are plenty of small usable designs. To be just different is really a form of hubris.

Engine, past a full VW just about everything is not just an experimental engine but as Dean Wormer would say experimental experimental engine. Doable but not mind free. A VW is as close to mind free as something like this gets.

The talent needs to be spent on the coveted folding wing, removable wing , or the one that disappears ( hopefully not in the air) to be different. Two piece fuselage. That can be transferred to other designs. All those brackets and mechanisms are extra weight. That’s the real penalty.

Easy to build is all in the builder’s mind. Easy is also not a time constraint. Fast to build is. But if you want to go there, fast and easy you can’t beat the Teenie Too. I will go out on a limb and say if you can’t build a T2 you can’t build an airplane. My video tape is long gone but watching them build up the second one on super 8 film is an exercise of everyone else overthinking it. The ten minutes of aerobatics and air to air after is down right entertaining. The small airplane get together footage is bonus gold. I digress.

Getting hung up on a material or process doesn’t get your plane built. Wood, welding, and riveting are all the simplest forms of building. Always will be. Simple defined as one can do by themselves. Every job requires tools. One not having the tool can always be rectified. Composite adds a precision that lurks under what looks simple. If one only sees what looks like making a bed, they are missing the game. If building is going to be drudgery instead of fun, you will not escape the jail. How it’s built does not matter.
 

JohnB

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RV-5 checks a lot of the boxes. Dave Carr( of 2 cyl vw fame) called a few months ago and the Five came up in the conversation. He loaned Van an engine for the plane and got to do most of the test flights, Nice flying airplane according to him. Prototype being restored by Van's employees as we speak.

The folding-removeable wing is crucial to this effort. John B
 

Vigilant1

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Folding/removable wings weren't specified in the OP. They do make any plane heavier and more complicated, but they have the potential to reduce costs so much that I suspect that feature would be very popular in a plane like this
 

Victor Bravo

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Clarification 1: My original intent was to strongly favor folding or quick-disconnect wings. That is something a large percentage of builders/buyers/operators would value.

Clarification 2: A modernized version of the Jeanie's Teenie or Teenie 2 is very close to what this thread is intended to discuss. The Teenie was hit pretty hard with the ugly stick, and for that reason alone I've never been particularly fond of it. But that is absolutely not a fair position for me to take, because I like the Zenith STOL airplanes and they're not Raquel Welch either.

So without changing the title of this thread, I would like to request that we consider this design exercise to be a nicer looking and perhaps easier to build airplane to occupy the same place in the HBA universe as the Teenie, using a less expensive and/or lighter engine than the VW.
 

karmarepair

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But if you want to go there, fast and easy you can’t beat the Teenie Too. I will go out on a limb and say if you can’t build a T2 you can’t build an airplane.
The Teenie Two plans are MISERABLE. They LOOK like plans, but were drawn by an illustrator and not an airplane designer. Lots of details are omitted, and there is nothing like a builders manual with the plans. The airplane itself is fine, and it was largely designed (I was TOLD, and I'm a little skeptical, as the time line doesn't look quite right, but the source <Veeduber> was in a position to know...) by Björn Andreasson when he was at Convair in the late 1950's.

The Jeanie's Teenie begat the Teenie Two which begat the Watson Wind Wagon which begat the Hummelbird which begat the Utracruiser and the H5. The Jeanie's Teenie also was the basis of John Monnett's first airplane. Monnett Mini - Wikipedia and there is the Bradley Aerobat....

For my money, for a metal single place full VW design, the H5 is the Way and the Truth, but the Thatcher CX-4 runs neck and neck with it. But we are talking about a different, lower horsepower airplane here....
 

Victor Bravo

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Most of those airplanes were created at a time when the $50 VW engine was growing on junkyard trees by the thousands, and a time when experimental airplanes were not held to the reliability standards we should very much want to impose today. A few guys like Pops and Scott Casler can build a reliable and powerful VW in their sleep for little money. The majority of today's potential "homebuilders" cannot.

I understand a VW weighs about 140-160 pounds by the time it is ready to bolt on to an airplane. Anything significantly less than that is possible (via Pops) but apparently it takes a lot of work or time to accomplish. The typical 60-80 HP VW in an airplane apparently burns 3.5 to 4 gallons an hour.

My understanding is that a reasonably clean airplane (Luciole, SD-1) can fly fairly well with a direct drive 25HP V-twin with not a whole lot of modifications. A few modest upgrades and tweaks can put this up to 29-30HP. A 40 HP big block V-twin weighs a little more, but makes a little more oomph, and the 40HP V-twins can likely be massaged up to 44-45HP without too much effort.

(TiPi and other V-twin experts, would you be kind enough to fact check me here?)

I am confident that an industrial V-twin, whether small block or big block, is significantly less weight than the VW. My understanding is that they will burn about 2 gallons an hour or even a little less. So (this thread's proposed) aircraft empty weight, gross weight, wing structure weight, fuselage structure weight to mount the engine, and the fuel weight can all be reduced. One of the old-school wiseguys around here always says "weight is the enemy", and I know that this is true.

So IMHO what is left is to design an airplane that is lower drag than the Teenie, and hopefully better looking (even the Moni, with all straight lines and single-axis bends, is fairly attractive and low drag). None of us mere mortals will ever achieve the low drag and panache that Monsieur Colomban can achieve, so we must bow our heads and humbly walk back our performance targets a ways from what the Luciole achieves.

Most importantly, there is already a thread about the 21st Century Volksplane, and that thread is intended to continue the preference for the 4 cylinder VW. So this thread can surely include discussion on the 2 cylinder Casler half-VW's, and V-twins, and perhaps even the little Continental 4A032 generator engines, but I'd like to request that the full 4 cylinder VW is more appropriate for the Volksplane thread.
 

Vigilant1

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Does anyone know of a direct-drive big block industrial V-twin with a significant field history in conventional fixed wing aircraft?

Are there existing new big block V-twin + PSRU combinations available new that weigh less than 125 lbs?
 

Tiger Tim

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Does anyone know of a direct-drive big block industrial V-twin with a significant field history in conventional fixed wing aircraft?

Are there existing new big block V-twin + PSRU combinations available new that weigh less than 125 lbs?
Alternatively, does anyone make a bolt-on third bearing and prop drive for an industrial V-twin? Do all V-twins have the same accessory mounting holes? Could such a third bearing be nearly universal?
 

Victor Bravo

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Does anyone know of a direct-drive big block industrial V-twin with a significant field history in conventional fixed wing aircraft?

Are there existing new big block V-twin + PSRU combinations available new that weigh less than 125 lbs?
The Luciole and SD-1 both have reasonable field history in Europe with the V-twin engines. but I think those are small blocks.

The "Backyard Flyer" ultralight had some amount of history with a big block V-twin and belt drive. The Kansas City Dawn Patrol WW1 replica group has significant history with the same (Valley Engineering) V-twin engine on several aircraft.

Para-Zoom in Germany not only has significant field history with small block V-twins on their PPC aircraft, they offer a bolt-on V-twin engine (with belt redrive) for sale.

So the direct accurate answers are no, I am not aware of a big block direct drive with field fleet data, and no I do not know of a big block with a PSRU that weighs under 125.

That being said, I would not have any reservations about trying out a direct drive big block on an experimental airplane. I would certainly go to Billski with the weights of the propeller and rotating engine components and ask whether he thought I was in a high risk or low-risk area as far as TV, but I do believe that big block engines are used with heavy flywheels and PTO devices, and I believe the torsional strength of the engine should have proven itself out to some reasonable degree.
 

cluttonfred

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At the time the VP-1 was introduced, the use of the VW Beetle engine in homebuilt aircraft was still relatively uncommon in North America, but the engines themselves were common and well understood, so the choice of engine was a big part of the “Hey, I can do that!” philosophy.

Given the electronic systems and general complexity of modern engines, and the resulting lack of hands on engine knowledge of most young people, there are only two ways I can see to do that today. FIrst, go with a conversion of the only relatively simple engines readily available, the industrial V-twins. Second, come up with a fully refined conversion of a modern auto/ATV/motorcycle engine as a parts kit or complete assembled engine. That engine should be readily available new from multiple sources to ensure availability and competitive pricing.

With these factors in mind, I really don’t see any engine option that beats a straight 1600-1915cc VW conversion in terms of bang for the buck in a low cost single seater even today. Take a look at Scott Casler’s prices to see how just building a bigger airframe to carry the full VW is a better deal.

32 HP at 3600 R.P.M. – 2 Cylinders – 85 lbs. (Slick Magneto w/Reconditioned Case, Hand Start) - $3,500.00
37 HP at 3600 R.P.M. – 2 Cylinders – 85 lbs. (Slick Magneto w/Reconditioned Case, Hand Start) - $4,000.00
42 HP at 3600 R.P.M. - 2 Cylinders - 84 lbs. (Slick Magneto, Aluminum NiCom Cylinders, Hand Start) - $4,900.00
45 HP at 3600 R.P.M. - 2 Cylinders - 84 lbs ( Slick Magneto, Aluminum NiCom Cylinders, Hand Start) - $5,000.00

50 HP at 3600 R.P.M. – 4 Cylinders – 140 lbs. (Slick Magneto w/New Case, Hand start 1600 cc) - $4,250.00
60 HP at 3600 R.P.M. – 4 Cylinders – 145 lbs. (Slick Magneto w/New Case, Hand start 1835 cc) - $4,450.00
65 HP at 3600 R.P.M. _ 4 Cylinders _ 145 lbs. (Slick Magneto w/New Case, Hand start 1915 cc - $4,475.00
76 HP at 3600 R.P.M. – 4 Cylinders – 147 lbs. (Slick Magneto w/New Case, Hand start 2180 cc) - $5,825.00
85 Hp at 3600 R.P.M. - 4 Cylinders - 147 lbs. (Slick Magneto w/New Case, Hand start 2400 cc) - $6,225.00
 

Vigilant1

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That being said, I would not have any reservations about trying out a direct drive big block on an experimental airplane. I would certainly go to Billski with the weights of the propeller and rotating engine components and ask whether he thought I was in a high risk or low-risk area as far as TV, but I do believe that big block engines are used with heavy flywheels and PTO devices, and I believe the torsional strength of the engine should have proven itself out to some reasonable degree.
It does get complicated, but has been explored a little here on HBA. In a nutshell;
1) The flywheels on these engines are on the opposite end as the PTO shaft. That flywheel also holds the starter gear, the alternator magnets, and (in most cases) the ignition "magneto's" magnets and trigger. If the prop is mounted on the PTO end of the crank and the flywheel etc is left on the other end, experience indicates the crank will eventually break.
2) In industrial use, there no analogue (MMOI - wise) to mounting a propeller directly to the PTO end.

So, for direct-drive use, the prop is either mounted to the flywheel end of the crank OR it is mounted to the PTO end and flywheel (and other components mentioned above) are either removed or drastically lightened to prevent there being significant mass on both ends of the crank.

If a big block with PSRU ends up at 125 to 135 lbs (and it will), then it is just 15 lbs short of the weight of a hand propped, smooth 4cyl VW. And the price will be about the same, but the VW will be very lightly stressed and last a long time.

Will the use of a big block V-twin change the nature of this project, due to the mass of these engines? The mass and expense edges very close to where a small 4 cyl VW looks like an attractive alternative. Maybe that's okay, but it didn't seem like the initial intent.

Fuel burn: I suspect all these air cooled pushrod 4 strokes will have about the same BSFC of about .45 lbs/HP/hr.
 
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cluttonfred

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With the Ace Aviation redrives for these engines priced at $760-860 delivered, why would you bother with direct drive? Something like the Luciole needs the direct drive because it's a very small, light, aircraft and every ounce counts, but a redrive seems like a much better option in most cases. A very clear step-by-step conversion manual for adapting a stock V-twin engine to aircraft use with an Ace redrive, perhaps with both tractor and pusher options, would, I think, not only encourage builders to design additional aircraft around the "Bob's Briggs Conversion" or what have you.
 
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