Wanted :186 cu in, Radial Y ; (30 hp) @ 1,300 rpm -- !

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TFF

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Actually the RC four stoke was primarily developed for point 3, compared to 2 stokes. Electric sucked for years. To me it still does. As for point one, they are catalytic ignition engines mostly. Regular ignition is always an upgrade but rarely needed for most flying. Low TBO is relative; 300 hours is a lifetime in RC. Point 4. Badge of honor
 

Bille Floyd

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...

Have you checked out the Bailey V5E 4-stroke?
...
This was the 4-stroke engine of choice on the Ariane Swift'Light motorglider. . One Swift pilot told me he loves it, and thought it was very reliable, but I have no real data on how long they last.
It's a souped-up 195cc single revving at 8,000RPM, with 3.19:1 PSRU included.
20.5hp, under 40 lb. even with electric start option. .. Not cheap ~$4,000
20,5 Hp will get me off the ground, (with Ease) at 2700-ASL , here
in Las Vegas ; but would it be enough to get me up, at 5,500-ASL
at King Mt Idaho ? When all done with pod and landing gears, i
expect my Exxtacy to weigh 240-Lb + 205 for the big-Ass pilot.

The Exxtacy gets a 17:1 glide , and is rated tandem for 160-Kg total pilot
weight ; so i'm still within the VNE max weight. I was told by the
airport owner, (who knows my glider well) ; i'd need 25-Hp to
do the job with certainty. Less than 25-Hp ; i might need a tow
assist to get me flying.

I really do hate 2-strokes ; but as of now i really don't see
another option than the Moster 185, or Hirth F-33 , to fit
the HP i'm looking for , and still come in under 40-Lb , with
the E-start ??

I guess the Valch Vm 420cc R5 radial, would be a bad choice
for dependability ; since there's so few of them out there to compare
with ?

Bille
 
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blane.c

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Bille Floyd

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Low TBO is relative; 300 hours is a lifetime in RC. Point 4. Badge of honor
I would think, that a lower turning rpm engine , would last longer ?
But Honda makes dirt bike engines , to run a few seasons, if you don't
abuse them : like the CR-250F 4-stroke, documented 38-Hp at
11,730 rpm .

@ blane.c
I'd like a 28-Hp continuous, radial-Y, that spun 2.5 to 3K-rpm , with electronic
ignition, EFI, and weighed 40-Lb, with the E-start ! :beer:

Bille
 

Bille Floyd

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I don't know about all the composite stuff, but sounds like you're looking for a Verner 3V:

http://scalebirds.com/scarlett-3vw

  • More than 30hp @2300 rpm (max 2500)
  • Approx half the weight of the Anzani (73 vs 143 lb)
  • Y-shape radial aesthetics!
Now, it's only 100cu-in displacement vs the 186 of the Anzani, but turning 2300 vs 1300 rpm, but you already mentioned being OK with that sort of RPM.
I looked at the first :20-seconds of the video, and the Y radial looks
to be shaking a Lot , compared to the 25-Hp , 5-cyl radial in this one
below:

Are more cylinders on a radial , (smoother) ?

The Valach VM 420 R5, is getting it's 25-Hp, out of a 420cc engine;
but it spins too fast at 4500rpm. What would Ya need to do
to slow the Valach down to 2500rpm ?

Bille
 

blane.c

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I would think, that a lower turning rpm engine , would last longer ?
But Honda makes dirt bike engines , to run a few seasons, if you don't
abuse them : like the CR-250F 4-stroke, documented 38-Hp at
11,730 rpm .

@ blane.c
I'd like a 28-Hp continuous, radial-Y, that spun 2.5 to 3K-rpm , with electronic
ignition, EFI, and weighed 40-Lb, with the E-start ! :beer:

Bille
I want Santa Claus to be real! But seriously I don't know anyone that makes that. However there are some possibilities depending on what you want. Do you want to fly or lament?

You could if you wanted to, get one of the little V engines and make a "fake cylinder" to put on the top or bottom, it could be made out of something light and be used to house something useful. With the help of some nerdy friends you could make a loudspeaker bark out the odd resonance needed to "get that authentic sound". That is the least expensive way. Otherwise suck it up and go on a diet, lose 33lbs … oops you want electric start … lose 41lbs and voilà it's the same difference in weight to buy a Scale Birds little Verner and you only need to use 28hp if that's all you want to use.
 

blane.c

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I looked at the first :20-seconds of the video, and the Y radial looks
to be shaking a Lot , compared to the 25-Hp , 5-cyl radial in this one
below:

Are more cylinders on a radial , (smoother) ?

The Valach VM 420 R5, is getting it's 25-Hp, out of a 420cc engine;
but it spins too fast at 4500rpm. What would Ya need to do
to slow the Valach down to 2500rpm ?

Bille
Jan Carlson about RPM vs POWER.png

So if you want decrease RPM to 2500RPM that is decrease to about 55%. The lowest the chart shows is a decrease to 63% were you get 25% of the power.
 
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ScaleBirdsScott

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I looked at the first :20-seconds of the video, and the Y radial looks
to be shaking a Lot , compared to the 25-Hp , 5-cyl radial in this one
below:

Are more cylinders on a radial , (smoother) ?

The Valach VM 420 R5, is getting it's 25-Hp, out of a 420cc engine;
but it spins too fast at 4500rpm. What would Ya need to do
to slow the Valach down to 2500rpm ?

Bille
More cylinders indeed smooths things out. So does higher RPM. On a basic level as you add cylinders to a radial you have shorter time between ignition events per revolution, for a given RPM.

There's a lot more going on that could factor into it, especially if someone is trying to design an engine, but I'm not actually enough of an engineer to do justice to a technical explanation.
 

blane.c

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While technically more complicated, a radial 2 stroke with a standard radial crankcase (no crankcase compression) and a supercharger is more elegant than a geared together 3, 4 or 5 singles geared together. The latter is obviously possible, and in some ways the problems are simpler.
"I think" much of the appeal of a radial is the exhaust note. So Low RPM Long Stroke comparative to displacement is what you want even "under square" (bore smaller diameter than stroke length) to get the RPM down in respect to displacement, if you want that sound.
 

tdfsks

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I think the closest engine to what you are looking for was the Pong Dragon radial.

The Pong "Dragon" designed by Alex Pong made its debut at OSH 1984. The "Dragon" was a six-cylinder, four-stroke engine that was very light and compact due to the ”two row three" configuration of it cylinders. Alex claimed 35 hp from 1400cc displacement at a weight of 44 pounds and a diameter of only 15 inches.

Like so many engine development projects, this one failed too. Not sure why. Some say that it was because of the choice of an even number of cylinders (vibration levels too high). This is the engine that the original Kitfox was designed around, hence the radial engine cowling. See pic below of it being tested in a Kitfox. There were several larger models and I suspect the one in the Kitfox was more than 35 hp.
Pong_Radial.thumb.jpg Kitfox_Test_283_Pong_Dragon_Radial_engine..thumb.jpg
 

Bille Floyd

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...

Like so many engine development projects, this one failed too. Not sure why. Some say that it was because of the choice of an even number of cylinders (vibration levels too high).
...
Interesting !!
Even number of cylinders, work good on boxer type engines ; but
not on radials . Why is that ?

I wonder what would happen if they had added a 3'rd ; to make
it a 3 row 9 cylinder ?

Bille
 

Dana

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4-stroke radials with a conventional master rod setup fire alternate cylinders, i.e. 1-3-2-1, 1-3-5-2-4-7, etc., while the non-firing cylinder is on the exhaust stroke. That doesn't work with an even number of cylinders. But in a multi row radial (as the Pong Dragon appears to be) there are separate master rods for each row, so you have an even total number of cylinders if you have an even number of rows; there have been many successful two and four row radials like this.

But that's interesting about the Kitfox, I did not know that. I always thought the radial cowling was just a styling choice.
 

Bille Floyd

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4-stroke radials with a conventional master rod setup fire alternate cylinders, i.e. 1-3-2-1, 1-3-5-2-4-7, etc., while the non-firing cylinder is on the exhaust stroke. That doesn't work with an even number of cylinders.
...
OK -- i see how that works now ; Thanks for your time !!

Bille
 

crusty old aviator

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Jack Hereford designed 3, 5, and 7 cylinder radial engines using VW cylinders. He sold kits for a while, then just plans, until that petered out. The 3 cyl engine was a personal project that flew well on a Flybaby. His company, with son, Andy, is called HCI Aviation.
 

Aviacs

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Jack Hereford designed 3, 5, and 7 cylinder radial engines using VW cylinders. He sold kits for a while, then just plans, until that petered out. The 3 cyl engine was a personal project that flew well on a Flybaby. His company, with son, Andy, is called HCI Aviation.
Beyond this You tube from 2008, & references from 2nd or 3rd parties, i can't find anything about the company or the airplane.
Do you have better info or contact information?


smt
 
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