2 stroke thread (with occasional F1 relevance!)

[uniflow]

Transfer port Injected 250 YZ
http://youtu.be/UEQli7nuak4

The YZ out doing the bussiness
http://youtu.be/1YG9ko8-Nwk

Transfer port injected F9 Kawasaki bighorn
http://youtu.be/ifSEql1X4R0

Bighorn Racing
http://youtu.be/eleqBGvOM4M

[autogyro]

A-G, you are correct about auto makers being wary about delving into general aviation..
Porsche really got their fingers burnt over aviation use of their air-cooled flat 6, ~20 years ago.

Here is another old Nazi-era device -somewhat conceptually akin to your naval usage..
http://www.youtube.com/watch?v=gP6VnbeWXSY

The Focke-Achgelis Fa 330 was one of the WW2 German military aircraft Ken looked at in 1946 when he was working at the enemy aircraft evaluation branch of the RAF.
This tethered AG uses a fully articulating rotor head like a helicopter.
Kens rotor head and fully integrated rotor uses a gimble bearing design that fully compensates for for the different angle of attack and lift characteristics of the leading and trailing blades.
No other AG has this level of lift efficiency which has been developed over 40 years.
The Wallis W116 has four times the range of a helicopter with a combat payload and hardly compares to a tethered observation AG that had to be cut free if an allied warship was sighted because the submarine crash dived.
The pilot (as recorded at the time) then drowned in the ordinary way.

[autogyro]

Autogyro, I sorry I should have shown a better picture of the gyro engine. It's NOT a Rotax, it's an Autoflight 700cc twin ( with ballance shaft ), the output is geared from the center of the crankshaft and has a rubber damper inside ( like a motorcycle clutch. It weighs under 40kg ( including electric strart and intergral gearbox ) produces a lazy ( low port timings ) 80 HP @6200 RPM. Prop is carbon fiber.
The down side is it's a standard twostroke so is less than efficent on fuel. BUT I have been working on semi direct injection ( as you see earlier in this thread on several motorcycle engines ) transfer port injection, this has shown a 14 to 21% fuel saving for the same power output. The idea is to ultimately transfer this injection to the gyro engines. There is a three cylinder version as well.
I know a little of Commander Wallis.

http://i1056.photobucket.com/albums/t38 ... ac6af4.jpg

6200 rpm will exceed the usable tip speed of the propeller at anywhere near full power.
The limitations of the airframe design only allow a prop diameter of some three feet on all but the ugliest AG designs that do not have the correct thrust to pitch moment characteristics anyway.
For a light AG to be usable it must be capable of high maneuverability at close to the hover. Most of its main operational roles are undertaken at these low speeds. Two strokes do not respond as well as four strokes in these conditions and that response is essential to flight safety.
I have been to too many fatal crashes of kit autogyros with Ken who was the AG crash investigator to consider inferior AG designs as anything other than in need of grounding until a proper definition of AGs is defined by the CAA.
This has been our position for many years.
It is a scandal that the CAA does not even have a definition of AG flight.
Fuel efficiency is another major requirement if the AG is to be anything other than an amateur leisure device.

[J.A.W.]

A-G, you are correct about auto makers being wary about delving into general aviation..
Porsche really got their fingers burnt over aviation use of their air-cooled flat 6, ~20 years ago.

Here is another old Nazi-era device -somewhat conceptually akin to your naval usage..
http://www.youtube.com/watch?v=gP6VnbeWXSY

The Focke-Achgelis Fa 330 was one of the WW2 German military aircraft Ken looked at in 1946 when he was working at the enemy aircraft evaluation branch of the RAF.
This tethered AG uses a fully articulating rotor head like a helicopter.
Kens rotor head and fully integrated rotor uses a gimble bearing design that fully compensates for for the different angle of attack and lift characteristics of the leading and trailing blades.
No other AG has this level of lift efficiency which has been developed over 40 years.
The Wallis W116 has four times the range of a helicopter with a combat payload and hardly compares to a tethered observation AG that had to be cut free if an allied warship was sighted because the submarine crash dived.
The pilot (as recorded at the time) then drowned in the ordinary way.

Well, A-G, is that your way of admitting that there IS some evidence of conceptual connection?
I should think functional detail improvements over time would indeed be a given..

& certainly, the survival rate of downed/orphaned submariners or airmen in oceanic combat - is normally fairly dismal..

[autogyro]

Having said all that uniflow, I congratulate you on a fine engine concept and for the ability to achieve a working engine.
I have thousands of images of many different light autogyro engines used by Wallis over the years.
I also have reams of paperwork including a complete flight training manual that includes military training in operational tasks.
There are many unfinished projects still available.
Just before Ken died earlier this year we were working on a new speed record aircraft and RAF Marham had agreed to set up the official course there.
We also wanted to attempt a height record of over 20,000 feet.
This would be relativly easy to achieve.
The un-supercharged W116 has already flown to 18,500 feet with no noticeable reduction in rotor lift and with turbocharging a height well over 20,000 should be achievable.

[J.A.W.]

Transfer port Injected 250 YZ
http://youtu.be/UEQli7nuak4

The YZ out doing the bussiness
http://youtu.be/1YG9ko8-Nwk

Transfer port injected F9 Kawasaki bighorn
http://youtu.be/ifSEql1X4R0

Bighorn Racing
http://youtu.be/eleqBGvOM4M

Good effort there U-F, I recall that back in the day, Kaw put a bit of effort into road-racing the Bighorn,
- since it was allowed to compete in an AMA (US) class against the 250 twins..

[J.A.W.]

Having said all that uniflow, I congratulate you on a fine engine concept and for the ability to achieve a working engine.
I have thousands of images of many different light autogyro engines used by Wallis over the years.
I also have reams of paperwork including a complete flight training manual that includes military training in operational tasks.
There are many unfinished projects still available.
Just before Ken died earlier this year we were working on a new speed record aircraft and RAF Marham had agreed to set up the official course there.
We also wanted to attempt a height record of over 20,000 feet.
This would be relativly easy to achieve.
The un-supercharged W116 has already flown to 18,500 feet with no noticeable reduction in rotor lift and with turbocharging a height well over 20,000 should be achievable.

Here's a hi-po 2T turbo option.. http://www.turboboyz.com/catalog/

[Nickel]

Where I live, 2 strokes sit in the back of every other pick up and show zero signs of going out of style. In the mountains, the deep snow means power to weight is of utmost importance. Motorcycles may have put the technology aside, but it's doing just fine around here.

As J.A.W. just posted, there is even a micro industry devoted to slapping turbos on efficient direct-injected 2 strokes. They sound mega.

https://www.youtube.com/watch?v=aCqaaWCwlY0

https://www.youtube.com/watch?v=ZR9uT3vNJ8k

or go crazy with tuning on a NA setup: https://www.youtube.com/watch?v=FOYVrWz4pLg

The direct injection really did make a world of difference as you can go demonstrably further on a tank of gas, plus you can roll it and it will fire up again first pull

[autogyro]

I would sooner do this on a mere 60hp.
18,500 feet and 11 hours endurance.
This is the 1960s by the way.

[uniflow]

Autogyro, you are right a direct drive version of this Autoflight twostroke would be a disaster, thats why the engine is geared. It my not be obvious at first sight. A flat power curve is whats needed for these type of aircraft, thats why only 80HP and low port timings. The next version will have higher ports and a power valve exhaust gate ( ECU controled ) This type of aircraft needs an engine with good power to weight, twostrokes offer this.
As a matter of interest the gyro ( that the Autoflight engine is bolted to ) is a Domminator, regarded as one of the most stable gyro designs ever built, center line thrust, can not power push over like may others can.
Sorry now we realy are off track.

Here is the engines first start. You can see in the seat a piece of metal that at approx 3500 starts to rattle around, nasty vibration. This hampered development, no matter what balance factor I used all it would do is change the vibration rpm.
It now sports a counter rotating balance shaft, much much better.
http://youtu.be/5DyPUqr4-CU

[autogyro]

Sorry mate but this is the W116 twin seater flying on 60hp four stroke.
It still has a superior performance to any current autogyro even with two people up.
Direct drive max 4,000 rpm.

We also did the music for the video which is a Wallis open day fly in.

[J.A.W.]

At the risk of continuing digression into matters of flight.. .. when replicas of WW1 planes were built for movies & such,
it was noted that period type airframes fitted with modern engines of ostensibly equivalent hp ratings did not match
the originals for flight performance.
This was due to the authentic WW1 mills being very large displacement low rpm units - which while modest in
specific out-put compared with modern types - actually were capable of spinning large fixed pitch props effectively,
due to the torque characteristics fundamental to large displacement engines.

The 2T, due to inherent power density/mass advantages - will be superior cc for cc, power & weight-wise,
-things (functional purpose, tune, fuel & etc) being equivalent..

Viz, compare the dyno charts of the two contemporary 3cyl 750cc engines - 2T VS 4T - shown below..

http://www.kawtriple.com/mraxl/articles ... bikes2.htm

[J.A.W.]

NASA produced this study back in 1980 - which considers the question of ICE efficiency parameters for G/Aviation..
&.. ..2-stroke wins.. (& ..sorry.. link improperly transcribed, now fixed)..

http://www.ntrs.nasa.gov/archive/nasa/c ... 011788.pdf

[uniflow]

If you want real performance, Dominator gyro two seat
http://youtu.be/2UPPSyf5QAU

[J.A.W.]

Or, what about a rotary piston mill for your rotary wing aircraft?
These shown below are diminutive wee things..
..but maybe a 20B triple rotor Toyo Kogyo would give it a kick up the jacksey..
..if a running a bit thirsty, just like VW & Subaru boxer 4S..
http://www.uavenginesltd.co.uk/products/