Lighweight opposite 2-stroke engines

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Yellowhammer

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Born In Alabama, reside: Louisiana (unfortunately)
Valery, I have used various chainsaws over the years. A husky 435 (41cc) is the newest model I've owned. It's an X-torq stratified charge model and despite the fact that I've richened the mixture a little from standard, it's by far the most frugal saw I've ever used. Other than using way less fuel, it's like older saws. If you can work out how to use the new stratified charge cylinders, they'd be worth trying out.

I must add that I have owned every type of chainsaw ever known to mankind in the United States. By far and away the very best I have owned has been the Echo Series; 440, 540, 640.

I retrieve sunken cypress logs during the summer months off of the waterways down here. I once was engaged in cutting a rather large log one afternoon with one of my Echo 440's and allowed my body weight to get too far forward and ended up falling into the water that was at least 9-10 feet deep. I sunk straight down and tried to keep the saw from getting wet but it was unavoidable.

I was in the water long enough to sink down and kick off of the bottom to get my saw out. My saw was submerged for at least 3-4 seconds and it never even stopped running. I was in total disbelief.

My next saw purchase will be the 600 series Echo Timberwolf. They are selling for just under $400 with a five (5) years Warranty.

Like a sore pecker, hard to beat.

Needless to say I was sold on the Echo series for life. It is my go to brand. They are lightweight, economical, robust, reliable, and easy to work on.

-Yellowhammer
 

Yellowhammer

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Born In Alabama, reside: Louisiana (unfortunately)
Hi, a glider doing what is called a roll-off launch is still a glider. A self launcher is by definition, powered; 2 or four stroke, turbojet or electric have flown. Early rocket power experiments where done with gliders culminating in the Me 163, and the X 15 and Space Shuttle. Two strokes are going the way of steam engines as the future is electric.

We will never fly on a purely electric motor depending on battery power for a long long time. WHile there has been much improvement in battery life, we are still a long was from a purely electrical fleet in operation.

As long as there are people who dream to fly on a budget and especially if they require a lot of power, two stokes will be around for many years to come. Even if Rotax discontinued the 582. There are too easy to make in your garage to go the way of the steam engine.

-Yellowhammer
 

mm4440

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LA area, CA
We will never fly on a purely electric motor depending on battery power for a long long time. WHile there has been much improvement in battery life, we are still a long was from a purely electrical fleet in operation.

As long as there are people who dream to fly on a budget and especially if they require a lot of power, two stokes will be around for many years to come. Even if Rotax discontinued the 582. There are too easy to make in your garage to go the way of the steam engine.

-Yellowhammer
The E(coNazis)PA can make them illegal.
 

Lendo

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Brisbane
Most engines unless it's Hydrogen have overlap to help with exhaust extraction and the Rotary is no exception. It's better to have a later fuel injection to keep that fuel out of the exhaust.
George
 

Urquiola

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Aug 23, 2013
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Madrid, Spain
View attachment 110435
Trying design charge cooling rotor wankel using RX8 housings, shaft, rotors and gears.

Rotors will a bit reworked or milled
View attachment 110436
Attached please find some old Yanmar Diesel documents about rotor recess, an image from a patent by a teacher of engineering at ICAI, Madrid, jesuit priest, Jose-Ignacio Martin-Artajo, you can also Rotor Surface J-I Martin-Artajo patent 1976 .jpghave a look at the current Aixro rotor shape, very original.
Blessings +
 

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Urquiola

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Madrid, Spain
The E(coNazis)PA can make them illegal.
Yes, pure electric flight is out of current technology reach, as of today, but this can soon change, there are many reports everyday about improvements in batteries and electric power storage. Hope they succeed soon.
'Eureka!' is, obviously: 'I reached it!'
Blessings +
 

Yellowhammer

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Born In Alabama, reside: Louisiana (unfortunately)
If I were thrashing around in deep murky water with a chainsaw, I'd be very grateful if it stopped running.:)

I completely agree with what your saying. I have trained myself over the years to push the kick back handle forward which stops the blade from turning when situations like that arise. I also have some scars on my legs where I was nowhere near water and the kick back got me and the kick back bar did not engage and lock the blade in place.

I am about to invest in one of those pneumatically operated saw that can run all day under water. provided the are connected to a compressor.
 

Aviacs

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I must add that I have owned every type of chainsaw ever known to mankind in the United States.
That includes quite a few interesting saws!
Weren't the original Wolfe saws made for dock work (1920's)?
IIRC, one version was pneumatic?

I've got a half dozen Disston 250cc 2 cyl twins, up to 5' bar.
Brothers & I actually used one for logging in the mid 70's.
Some felling, but it was mostly good for bucking. It get's "interesting" staying coordinated for 2 guys when felling something big....

Mall made some good saws as well, never owned one of them.

Reed-Prentice, Titan, IEL, Danarm were all respected.

smt
 
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Kiwi303

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Jul 22, 2015
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En Zed. Aka The Shire.
My "New" saw I got two weeks ago is actually pretty old. It's marked "Made in West Germany"

Sachs-Dolmar 133
85cc
made between 1979 and 1987

It has a LOT of torque for a chainsaw, they tend to be revvers, this thumps away remorselessly.
 

Aviacs

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Oct 21, 2019
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243
My "New" saw I got two weeks ago is actually pretty old....Sachs-Dolmar 133.......made between 1979 and 1987....
Kids these days!
Dolmar started in 1927

It has a LOT of torque for a chainsaw, they tend to be revvers, this thumps away remorselessly.

85cc
Original model A had 15 cu. in. (247cc)
That was a thumper.

Danarm made saws up to 350cc.

Yellowhammer mentioned he tried all the US saws ever made & wanted a pneumatic.
I was a little off on the timeline for Wolf.
Started 1920 with electric chainsaw, made the pneumatics ca. 1927 onward for use on docks and in log ponds.
Stihl was still electric in 1926, not sure it has been settled who made 2 strokes first in Germany, Stihl or Dolmar.
They both came out with commercially successful 2 stroke models in 1927
From then until WW2 quite a few saw companies sprang up in NA & Europe & probably did as much for the development of 2 stroke motors as anything. Even Andreas Stihl proving grounds was big USA west coast timber.
2 stroke development, partially in that market, (& some motorcycles) gets back to aviation via drones during & after the war years.

smt
 
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jbiplane

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Jan 29, 2014
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323
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Krasnoyarsk, Russia
LC Engine progressed
Just one 344cc motor for 25kw generator was build and I build and buy most spares for second one. May be I shift focus on 500cc LC inlines which will use Yamaha outboards linings, crankshafts, conrods and pistons to simplify customer life worldwide.
 
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