The rise of FrankenEngine - An engine for the VP-21

Help Support Homebuilt Aircraft & Kit Plane Forum:

sotaro

Well-Known Member
I am such a fan of three engines maybe three cylinders is just a natural progression? So are three cylinders pop, wheeze, pop, wheeze, pop, wheeze?
The most common three cylinder crankshaft looks like one half of an inline 6 cylinder crank, three throws, each 240 degrees apart. Most recent automotive 3 cylinders have balance shafts. Ford introduced one about a decade ago that did not have a balance shaft, but the ancillaries were carefully placed, along with the crank and flywheel, to mitigate vibration. Parallel twins, which you were asking about before, have a variety of vibration issues, that in current motorcycle and automotive practice (FIAT), are mitigated with balance shafts. Air cooled twin cylinder motorcycles of the 1960-70s, could be divided roughly into two large camps, British 360 degree cranks where the pistons rose and fell together, "pop, wheeze, pop, wheeze,". Designed almost a generation later, Japanese motorcycles had 180 degree cranks where the pistons alternated rising and fallin. This led to a rocking couple, one end then the other of the engine rising and falling. Among the Japanese 4 strokes, the sound would be pop, pop, wheeze, wheeze.

Geraldc

Well-Known Member
For the crankshaft we have this one. Be a shame to cut it in half.

speedracer

Well-Known Member
Maybe the proper question to ask would be "What is the continuous power of a HardlyLeakingson* with aircraft style cooling shrouds?"?
I don't think anyone really knows?

*My father was the first Harley dealer in my state and I spent summers working off my new Schwinns back in the shop. I actually have pretty neutral opinions of Harleys other than being quit intimidated by their weight when I had to move one, back when I was 10. The Laverda wasn't quite as bad but I was a little older then as well.

Edit: This presumes that the limit is due to heat dissipation. It could be the volume of the oil tank !?!
What is the continiuos([email protected]) power output of a hardlygoingson?
Hardlygoingson/hardlyleakingson LOL. I've often wondered why anyone would want to ride the SLOWEST road bike available.

PMD

Well-Known Member
Hardlygoingson/hardlyleakingson LOL. I've often wondered why anyone would want to ride the SLOWEST road bike available.
My wife has a 1964 Honda 50 cub, and I can assure you there IS a motorbike slower than a Harley Fergusson. PS: the Honda handles better though.

delta

Well-Known Member
I have a Homelite 55hp outboard engine that has a Crosley sohc 4 stroke power head. The block construction lends itself to many configurations.

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
Double thanks for the link!!
It lead to this caster:
Very obviously one of those rare BTDT types that is more concearned with results rather than image. Learned a few common sense tricks that I'll be integrating into my next casting session.

GeeZee

Well-Known Member
HBA Supporter
Double thanks for the link!!
It lead to this caster:
Very obviously one of those rare BTDT types that is more concearned with results rather than image. Learned a few common sense tricks that I'll be integrating into my next casting session.
Yea that Kelly Coffield is quite the guy. He has a boatload of very interesting vids.
I wonder if he would do parts for (reasonable) . His overhead is certainly very low.

delta

Well-Known Member
It's to bad the 3 cylinder's not currently in production and the price is to high. Vernal Radial Engines — BRAHN Sport Aircraft
It might be possible to convert a 2 stroke to a 4 stroke with a camless electromagnetic valve situation.

spikews

Member
My wife has a 1964 Honda 50 cub, and I can assure you there IS a motorbike slower than a Harley Fergusson. PS: the Honda handles better though.
I have a Honda Sport 65 made in 65. It's slower than any of my Harley Davidsons! Harleys don't leak any more. Also the so-called leak was from the primary chain lube. Which wasn't all that bad. Hows that for an answer to an unspoken question?

blane.c

Well-Known Member
HBA Supporter
Double thanks for the link!!
It lead to this caster:
Very obviously one of those rare BTDT types that is more concearned with results rather than image. Learned a few common sense tricks that I'll be integrating into my next casting session.
Most common problem with foundry work is neighbors. Do your foundry work in the dead of night while a strong storm is raining, thunder and lightning and all that to cover the smell and dissipate the ash field.

PMD

Well-Known Member
I have a Honda Sport 65 made in 65. It's slower than any of my Harley Davidsons! Harleys don't leak any more. Also the so-called leak was from the primary chain lube. Which wasn't all that bad. Hows that for an answer to an unspoken question?
Meant to reply when this post was fresh....sorry I have been travelling/holidaying so a bit late.

My lifetime M/C best bud (a Daytona winner) started riding on a sport 65. If I remember right, it actually had a clutch and gearbox. I had an A-10 Super Rocket at that time, and we used the little Honda two up for parts chasing and even touring when the Beezer was down. It was a HUGE step up from a step through!

spikews

Member
Meant to reply when this post was fresh....sorry I have been travelling/holidaying so a bit late.

My lifetime M/C best bud (a Daytona winner) started riding on a sport 65. If I remember right, it actually had a clutch and gearbox. I had an A-10 Super Rocket at that time, and we used the little Honda two up for parts chasing and even touring when the Beezer was down. It was a HUGE step up from a step through!
Yes it has a 4 speed and manual clutch. Sorta like a REAL M/C

AJLiberatore

Well-Known Member
A bit of background:
A little more than a decade ago I decided I needed an engine for my Quickie project because the Onan was no longer available. I built a ½ VW with the intention of using that. Ultimately I decided that it wasn’t a good choice. This lead to thinking about building an engine from scratch and make it a for profit project. At the time I had access to the equipment and time to do just that. To keep it all manageable I decided to use as many off the shelf parts as I could to keep the custom work, and cost/time to a minimum.
Life changed for me and Pete introduced the O-100. The O-100 was so close to what I had designed (market niche, not design) I decided the project was no longer a commercially viable one. I no longer have the resources to build such and engine - but I haven't given up. I'm still working on an inverted 810 B+S, even if it ends up being just for my Quickie
With the O-100 in limbo and supply of the little v-twins looking a little precarious maybe it’s time to resurrect that old project? Thus, this new thread.

Objectives:
Gather ideas, in the spirit of the VP-21 and Motorcycle Of The Air threads, to design an engine suitable for this class of EABs. Project is to be open source so individuals can build from scratch, use cottage industry parts or buy complete FWF packages.

Controlling parameters:
Opposed 2 cylinder.
4 stroke direct drive
Maximum RPM = 3600 ………… less is better.
30+ Horse power. 40 would be better. This means 60 cubic inches (1.0L), or more, if we use 0.5 Hp/cu/ in. as a base line.
80 pounds maximum weight ready to bolt to the engine mount, minus prop and exhaust.
Should run on 85 octane E10 or low Sulfur Diesel (not both – pick one)
As many off the shelf (OTS) parts as possible. Minor modifications acceptable. This means those that can be done with hand tools or at ANY machine shop.
The OTS parts should be sourced from current production or past vehicles that have been produced in million+ quantities.
Simple. No dual OHC, VVT, variable compression, 12 valves per cylinder or antimatter containment fields.
Unless someone comes up with another option it will be presumed that this will mean a clean sheet engine case/block is needed along with either clean sheet heads or those built in the fashion of the ½ VW or ½ Corvair.
Past engines to use as templates:
Onan
1/2 VW
1/2 Corvair
Aeronca E-113
Conteniental A-40
O-100
Franklin 2 cylinders
I've been thinking about the Onan and Cushman engines. Both 18 to 22 hp in the Horizontally Opposed Config.

FWIW scan one (via 3d scanning devices) and design off that architecture and scale it to the 40hp class. Or, do you make 4 cylinder versions.

Yes massive weight reductions needed, CAD-FEA can help get you closer.

However in the case of the Onan, it's a flat head and the RPM's are in your design spec arena, it fits the KISS mantra for sure. It's a Config that will work, we just need more Cu In's.

Well-Known Member
HBA Supporter
how about a half-Jabiru?

AJLiberatore

Well-Known Member
how about a half-Jabiru?
They built one and it was mounted on an airframe. I have the photo somewhere. It didn't go forward and I'd love to know the story behind it. if someone does, please chime in....

TiPi

Well-Known Member
HBA Supporter
Log Member
They built one and it was mounted on an airframe. I have the photo somewhere. It didn't go forward and I'd love to know the story behind it. if someone does, please chime in....
The 1/2 Jabiru would suffer from the same cost penalty as the 1/2 Rotax 912: 50% of the power at about 75% or more of the cost of the full version. Both engines are very poor candidates for a 1/2 engine as they have essential items on both ends of the engine, so you can’t just cut off the front or rear part.
For a 30-40hp aircraft engine, you need to start with the most suitable low cost engine or components and add or modify what is not suitable for that particular application. Don’t start with the most expensive aircraft engine and then add cost to remove a couple of cylinders. That might work if there are lots of run-out engines or surplus parts available.

Last edited: