DIY Two-Stroke Engine

"bod43" wrote

www.deltahawk.com

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

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

I'll believe it when I see that the first 25 are sold and flying. It has
been ready for production for the past 10 or more years, yet, it always a
year away from being released for production.

Hint: I'll win this bet.
--
Jim in NC

wrote in message
...
On Tue, 9 Mar 2010 04:36:58 -0800 (PST), 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
For the last 10 years.

Surprise, Surprise. There is a two seat experimental Helicopter in
Australia that is undergoing flight tests as I write this. It is using the
Deltahawk two stroke diesel engine. see www.deltahelicopters.com.au
Unfortunately the Deltahawk engines are priced right up there with the long
time proven Lycomings. It will take some time to really see if this engine
will demonstrate all the potential advantages inherent in the diesel
concept.

"Morgans" wrote in message
...
Most have the gearbox made as one with the lower crankcase. You can't get
the weight off of the engine, and the gears in the bike tranny are not tough
enough to run a prop, so you have to live with the weight and figure out a
way to get the power out of the case without using the gearbox. Big
problem.

Of course, that is not so with Harley & clone V-twins and at least some BMW
engines (Yes, I know. They are 4-stroke and this thread is about 2-stroke
engines)

Vaughn

Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

durabol wrote:
Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

That RPM isn't going to give you much prop efficiency.

A more spindly engine with higher displacement may be lighter overall --
and certainly mechanically simpler -- than a little fast engine and a
speed reducer.

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

On Mar 14, 11:30*pm, durabol wrote:
Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

'Restrictive' exhaust isn't a good way to avoid venting unburnt fuel,
and it will really clobber performance. If you're really trying to
get good performance, especially over a narrow band, then you really
need to consider using tuned pipes (AKA "Expansion Chambers"). Gordon
Jennings "Two Stroke Tuners Handbook" covers most everything you need
to design a two-stroke.
4000 RPM is pretty low for a two-stroke. The tuned length for the
pipe(s) would be around 6 FEET.

Grider Pirate wrote:
On Mar 14, 11:30 pm, durabol wrote:
Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

'Restrictive' exhaust isn't a good way to avoid venting unburnt fuel,
and it will really clobber performance. If you're really trying to
get good performance, especially over a narrow band, then you really
need to consider using tuned pipes (AKA "Expansion Chambers"). Gordon
Jennings "Two Stroke Tuners Handbook" covers most everything you need
to design a two-stroke.
4000 RPM is pretty low for a two-stroke. The tuned length for the
pipe(s) would be around 6 FEET.

Ship's two-stroke diesel engines top out at less than 200RPM.

I don't think they use tuned pipes, but if they did I suppose they'd
have room.

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

Tim Wescott wrote:
Grider Pirate wrote:
On Mar 14, 11:30 pm, durabol wrote:
Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

'Restrictive' exhaust isn't a good way to avoid venting unburnt fuel,
and it will really clobber performance. If you're really trying to
get good performance, especially over a narrow band, then you really
need to consider using tuned pipes (AKA "Expansion Chambers"). Gordon
Jennings "Two Stroke Tuners Handbook" covers most everything you need
to design a two-stroke.
4000 RPM is pretty low for a two-stroke. The tuned length for the
pipe(s) would be around 6 FEET.

Ship's two-stroke diesel engines top out at less than 200RPM.

I don't think they use tuned pipes, but if they did I suppose they'd
have room.

Don't need them. They all have massive
blowers for scavenging.

I believe EMD built locomotive 2-strokes that
had a set of exhaust valves in the head and
a blower port that was opened at the bottom of
the stroke. No tuning, the blower was plenty
to force out the exhaust and fill the cylinder
with fresh air.

On Thu, 18 Mar 2010 13:39:45 -0700, Tim Wescott
wrote:

Grider Pirate wrote:
On Mar 14, 11:30 pm, durabol wrote:
Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

'Restrictive' exhaust isn't a good way to avoid venting unburnt fuel,
and it will really clobber performance. If you're really trying to
get good performance, especially over a narrow band, then you really
need to consider using tuned pipes (AKA "Expansion Chambers"). Gordon
Jennings "Two Stroke Tuners Handbook" covers most everything you need
to design a two-stroke.
4000 RPM is pretty low for a two-stroke. The tuned length for the
pipe(s) would be around 6 FEET.

Ship's two-stroke diesel engines top out at less than 200RPM.

I don't think they use tuned pipes, but if they did I suppose they'd
have room.
They are also supercharged. (forced induction)

On Thu, 18 Mar 2010 14:17:50 -0700, Jim Stewart
wrote:

Tim Wescott wrote:
Grider Pirate wrote:
On Mar 14, 11:30 pm, durabol wrote:
Thanks for the responses. I meant for ultralight or light aircraft
with 20-40hp from 1 or 2 cylinders. I definitely want to copy as much
as I can since I'm not engineer. I planned to have the RPM at about
4000 in order to get enough power out of the engine but I may reduce
the rpm if I can get enough power. Also I may have to weld the crank
together to handle the propeller loads.

Brock

'Restrictive' exhaust isn't a good way to avoid venting unburnt fuel,
and it will really clobber performance. If you're really trying to
get good performance, especially over a narrow band, then you really
need to consider using tuned pipes (AKA "Expansion Chambers"). Gordon
Jennings "Two Stroke Tuners Handbook" covers most everything you need
to design a two-stroke.
4000 RPM is pretty low for a two-stroke. The tuned length for the
pipe(s) would be around 6 FEET.

Ship's two-stroke diesel engines top out at less than 200RPM.

I don't think they use tuned pipes, but if they did I suppose they'd
have room.

Don't need them. They all have massive
blowers for scavenging.

I believe EMD built locomotive 2-strokes that
had a set of exhaust valves in the head and
a blower port that was opened at the bottom of
the stroke. No tuning, the blower was plenty
to force out the exhaust and fill the cylinder
with fresh air.
And at 200 RPM there is LOTS of time to purge and fill. Volumetric
efficiencies are pretty good.