DIY Two-Stroke Engine

On Sun, 7 Mar 2010 23:04:37 +0000, Nigel Eaton
wrote:

In article
,
bizguy writes
You could look at outboard motors as a starting point. In the past I
read of someone using a Mercury to get 100 hp in an aircraft.

That seems unlikely, to be honest. I've never met an outboard that
wasn't cooled by pumped water.
Can be cooled very well with a radiator - the interface to connect a
rad instead of the raw water cooling was possible, but not simple.
There were "saltie" conversions that used a sealed cooling system and
a heat exhanger availble for some of the outboards of the period, but
they were not common. Very common with stern-drives (4 stroke)

Actually, there WAS a commercially available helicopter kit that DID
use the V4 Evinrude power head - and I believe I've seen refference to
the 6 cyl Merc "black max" in experimental aircraft use too.

Nigel Eaton wrote:
In article
,
bizguy writes
You could look at outboard motors as a starting point. In the past I
read of someone using a Mercury to get 100 hp in an aircraft.

That seems unlikely, to be honest. I've never met an outboard that
wasn't cooled by pumped water.



I had a really nice 5 HP Briggs and Stratton outboard on my previous
sailboat. It was air cooled. But it was the exception that proved
the rule...

http://www.duckworksmagazine.com/03/...p/06/index.htm
--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/

cavelamb wrote:
Nigel Eaton wrote:
In article
,
bizguy writes
You could look at outboard motors as a starting point. In the past I
read of someone using a Mercury to get 100 hp in an aircraft.

That seems unlikely, to be honest. I've never met an outboard that
wasn't cooled by pumped water.



I had a really nice 5 HP Briggs and Stratton outboard on my previous
sailboat. It was air cooled. But it was the exception that proved
the rule...

http://www.duckworksmagazine.com/03/...p/06/index.htm

Without knowing anything much about ultralights (beyond they look fun
but dangerous) wouldn't the obvious source of lightweight engines in
that power range be motorcycle engines?

-- Peter Fairbrother

"durabol" wrote in message
...
For the last few years I have toyed with the idea of building a
homemade two-stroke engine for UL use. What keyed my interest was
reading about homemade model aircraft engines and reading and watching
a re-enactment of the Wright brother's first flight with a replica
engine (not a two-stroke engine).

Has anyone made a 2-stroke engine from scratch? One may need to cast
aluminium, may need a lathe and milling machine with boring head and
hone or perhaps the boring and honing of the cylinder and bearing
journals could be farmed out. A commercial carburetor and piston could
be used. Two-stroke engines seem simple enough that home construction
may be possible, if not practical.

A direct drive engine will be that much heavier when you take into
account the weight of the drive reduction system. I have calculated
the weight of an 80x80mm bore and stroke 2 cylinder opposed engine and
it was a bit under 40lbs which should give about 1hp/lbs. I used 10mm
cylinder and crankcase wall thickness and a 1.25" dia crank.

I have got some idea of port-time-area from the freeware computer
program called "BiMotion". I'm not sure how good the data is for
lowish speed engines but I guess it is a start. I have also worked up
a spreadsheet for similar information.

I don't think a reed valve system is needed for this engine since it
is only going to operate at a fairly narrow rpm range and the port
timing isn't critical. Piston ported valves offer similar performance
to other induction types but only over a narrow rpm range which is
what I have planned for the engine. I plan to build an engine with a
restrictive exhaust to ensure no fuel escapes. I have heard that
piston ported engines can spit some fuel out of the carb at idle but
this doesn't seem like a major problem. Rotary valves via crank shaft
induction (disk or drum valves as well) is an interesting idea but I
don't think I need the critical timing they provide.

I was planning on using the largest two-stroke piston (not a diesel
piston) I could find and using the largest stoke that was reasonable,
something like 90x105mm

Brock

How about a 2 stroke radial developed by Pontiac for their X-4 1,500lb
car in 1969.
http://www.popsci.com/archive-viewer...lt+airpl anes

Popular Science has just released ALL of their archives for free
http://www.popsci.com/archives and found it while searching for
homebuilt airplanes.

--
A man is known by the company he keeps- Unknown

Anyolmouse

On 8 Mar, 22:28, "Anyolmouse" wrote:
"durabol" wrote in message

...



For the last few years I have toyed with the idea of building a
homemade two-stroke engine for UL use. What keyed my interest was
reading about homemade model aircraft engines and reading and watching
a re-enactment of the Wright brother's first flight with a replica
engine (not a two-stroke engine).

Has anyone made a 2-stroke engine from scratch? One may need to cast
aluminium, may need a lathe and milling machine with boring head and
hone or perhaps the boring and honing of the cylinder and bearing
journals could be farmed out. A commercial carburetor and piston could
be used. Two-stroke engines seem simple enough that home construction
may be possible, if not practical.

A direct drive engine will be that much heavier when you take into
account the weight of the drive reduction system. I have calculated
the weight of an 80x80mm bore and stroke 2 cylinder opposed engine and
it was a bit under 40lbs which should give about 1hp/lbs. I used 10mm
cylinder and crankcase wall thickness and a 1.25" dia crank.

I have got some idea of port-time-area from the freeware computer
program called "BiMotion". I'm not sure how good the data is for
lowish speed engines but I guess it is a start. I have also worked up
a spreadsheet for similar information.

I don't think a reed valve system is needed for this engine since it
is only going to operate at a fairly narrow rpm range and the port
timing isn't critical. Piston ported valves offer similar performance
to other induction types but only over a narrow rpm range which is
what I have planned for the engine. I plan to build an engine with a
restrictive exhaust to ensure no fuel escapes. I have heard that
piston ported engines can spit some fuel out of the carb at idle but
this doesn't seem like a major problem. Rotary valves via crank shaft
induction (disk or drum valves as well) is an interesting idea but I
don't think I need the critical timing they provide.

I was planning on using the largest two-stroke piston (not a diesel
piston) I could find and using the largest stoke that was reasonable,
something like 90x105mm

www.deltahawk.com

Too big for ultralight I would guess but seems like
a very fine plan for a light aircraft engine.

160 hp and upwards

V4 two stroke diesel.

Has crank driven air pump + turbo.

No electrics *at_all* for engine operation.

Will continue running if air pump OR turbo fails.
Will run at about 50% power (check web site for details)
if all water is lost.

Seems a *very* fine thing to me.

Expected to be accepted as a FAA certified
aero engine this year.

200hp planned.

V8 in the future.

On 9 Mar, 03:47, bod43 wrote:
On 8 Mar, 22:28, "Anyolmouse" wrote:



"durabol" wrote in message

...

For the last few years I have toyed with the idea of building a
homemade two-stroke engine for UL use. What keyed my interest was
reading about homemade model aircraft engines and reading and watching
a re-enactment of the Wright brother's first flight with a replica
engine (not a two-stroke engine).

Has anyone made a 2-stroke engine from scratch? One may need to cast
aluminium, may need a lathe and milling machine with boring head and
hone or perhaps the boring and honing of the cylinder and bearing
journals could be farmed out. A commercial carburetor and piston could
be used. Two-stroke engines seem simple enough that home construction
may be possible, if not practical.

A direct drive engine will be that much heavier when you take into
account the weight of the drive reduction system. I have calculated
the weight of an 80x80mm bore and stroke 2 cylinder opposed engine and
it was a bit under 40lbs which should give about 1hp/lbs. I used 10mm
cylinder and crankcase wall thickness and a 1.25" dia crank.

I have got some idea of port-time-area from the freeware computer
program called "BiMotion". I'm not sure how good the data is for
lowish speed engines but I guess it is a start. I have also worked up
a spreadsheet for similar information.

I don't think a reed valve system is needed for this engine since it
is only going to operate at a fairly narrow rpm range and the port
timing isn't critical. Piston ported valves offer similar performance
to other induction types but only over a narrow rpm range which is
what I have planned for the engine. I plan to build an engine with a
restrictive exhaust to ensure no fuel escapes. I have heard that
piston ported engines can spit some fuel out of the carb at idle but
this doesn't seem like a major problem. Rotary valves via crank shaft
induction (disk or drum valves as well) is an interesting idea but I
don't think I need the critical timing they provide.

I was planning on using the largest two-stroke piston (not a diesel
piston) I could find and using the largest stoke that was reasonable,
something like 90x105mm

www.deltahawk.com

Too big for ultralight I would guess but seems like
a very fine plan for a light aircraft engine.

160 hp and upwards

V4 two stroke diesel.

Has crank driven air pump + turbo.

No electrics *at_all* for engine operation.

Will continue running if air pump OR turbo fails.
Will run at about 50% power (check web site for details)
if all water is lost.

Seems a *very* fine thing to me.

Expected to be accepted as a FAA certified
aero engine this year.

200hp planned.

V8 in the future.

Oh yes - direct drive. No gears needed.

bod43 wrote:
On 8 Mar, 22:28, "Anyolmouse" wrote:
"durabol" wrote in message

...



For the last few years I have toyed with the idea of building a
homemade two-stroke engine for UL use. What keyed my interest was
reading about homemade model aircraft engines and reading and watching
a re-enactment of the Wright brother's first flight with a replica
engine (not a two-stroke engine).
Has anyone made a 2-stroke engine from scratch? One may need to cast
aluminium, may need a lathe and milling machine with boring head and
hone or perhaps the boring and honing of the cylinder and bearing
journals could be farmed out. A commercial carburetor and piston could
be used. Two-stroke engines seem simple enough that home construction
may be possible, if not practical.
A direct drive engine will be that much heavier when you take into
account the weight of the drive reduction system. I have calculated
the weight of an 80x80mm bore and stroke 2 cylinder opposed engine and
it was a bit under 40lbs which should give about 1hp/lbs. I used 10mm
cylinder and crankcase wall thickness and a 1.25" dia crank.
I have got some idea of port-time-area from the freeware computer
program called "BiMotion". I'm not sure how good the data is for
lowish speed engines but I guess it is a start. I have also worked up
a spreadsheet for similar information.
I don't think a reed valve system is needed for this engine since it
is only going to operate at a fairly narrow rpm range and the port
timing isn't critical. Piston ported valves offer similar performance
to other induction types but only over a narrow rpm range which is
what I have planned for the engine. I plan to build an engine with a
restrictive exhaust to ensure no fuel escapes. I have heard that
piston ported engines can spit some fuel out of the carb at idle but
this doesn't seem like a major problem. Rotary valves via crank shaft
induction (disk or drum valves as well) is an interesting idea but I
don't think I need the critical timing they provide.
I was planning on using the largest two-stroke piston (not a diesel
piston) I could find and using the largest stoke that was reasonable,
something like 90x105mm

www.deltahawk.com

Too big for ultralight I would guess but seems like
a very fine plan for a light aircraft engine.

160 hp and upwards

V4 two stroke diesel.

Has crank driven air pump + turbo.

No electrics *at_all* for engine operation.

Will continue running if air pump OR turbo fails.
Will run at about 50% power (check web site for details)
if all water is lost.

Seems a *very* fine thing to me.

Expected to be accepted as a FAA certified
aero engine this year.

200hp planned.

V8 in the future.

That link redirects to a poster site.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

On Mar 8, 11:55*pm, Tim Wescott wrote:
...
www.deltahawk.com

That link redirects to a poster site.
Tim Wescott

http://www.deltahawkengines.com/

Any day now.....

jsw

Jim Wilkins wrote:
On Mar 8, 11:55 pm, Tim Wescott wrote:
...
www.deltahawk.com

That link redirects to a poster site.
Tim Wescott

http://www.deltahawkengines.com/

Any day now.....

jsw

saw the price? 71 Thou $$$$$$

Anna wrote:
Jim Wilkins wrote:
On Mar 8, 11:55 pm, Tim Wescott wrote:
...
www.deltahawk.com

That link redirects to a poster site.
Tim Wescott

http://www.deltahawkengines.com/

Any day now.....

jsw

saw the price? 71 Thou $$$$$$

sorry, 'only' 62.500$ for Deltahawk