DIY Two-Stroke Engine

bod43 schreef:

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.

Yes yes, nice stuff though expensive. But the original question was
about building one's engine from scratch.

On Mar 9, 10:37*am, jan olieslagers
wrote:
bod43 schreef:
...
V4 two stroke diesel.
Yes yes, nice stuff though expensive. But the original question was
about building one's engine from scratch.

After spray cans you want yet another safety rant?

jsw

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 $$$$$$

Not out of line for an engine that's capable of being certified but
hasn't been yet.

Aero engines are expensive. That's why folks go to great lengths to
modify car engines to fly airplanes. When they're done, the engines are
-- expensive.

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

Jim Wilkins wrote:
On Mar 9, 10:37 am, jan olieslagers
wrote:
bod43 schreef:
...
V4 two stroke diesel.
Yes yes, nice stuff though expensive. But the original question was
about building one's engine from scratch.

After spray cans you want yet another safety rant?

jsw



THAT, more than likely, just won't happen.

Fred Blanton did it.
But it took his entire adult life time.

So this thread is about TALKING about building
and engine from scratch.

Not actually building one...

--

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

cavelamb wrote:
Jim Wilkins wrote:
On Mar 9, 10:37 am, jan olieslagers
wrote:
bod43 schreef:
...
V4 two stroke diesel.
Yes yes, nice stuff though expensive. But the original question was
about building one's engine from scratch.

After spray cans you want yet another safety rant?

jsw



THAT, more than likely, just won't happen.

Fred Blanton did it.
But it took his entire adult life time.

So this thread is about TALKING about building
and engine from scratch.

Not actually building one...

Henry Ford did it, in his garage, over the space of a year or two.

But the performance wasn't high.

The Wright Brothers did it, over the space of a year or two, and even
though the performance wasn't high it was still good enough!

Talking about building stuff can get you a lot more bang for the buck
than actually doing it. Witness me, with several engine parts sitting
next to a lathe that's been idle for days, and last had an accessory for
a completely different engine built on it, not a part for the engine
that's half-done and sitting next to it.

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

durabol wrote:
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

http://www.s363.com/Elbridge/aee.html

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

Tim Wescott wrote:
cavelamb wrote:
Jim Wilkins wrote:
On Mar 9, 10:37 am, jan olieslagers
wrote:
bod43 schreef:
...
V4 two stroke diesel.
Yes yes, nice stuff though expensive. But the original question was
about building one's engine from scratch.

After spray cans you want yet another safety rant?

jsw



THAT, more than likely, just won't happen.

Fred Blanton did it.
But it took his entire adult life time.

So this thread is about TALKING about building
and engine from scratch.

Not actually building one...

Henry Ford did it, in his garage, over the space of a year or two.

But the performance wasn't high.

The Wright Brothers did it, over the space of a year or two, and even
though the performance wasn't high it was still good enough!

Talking about building stuff can get you a lot more bang for the buck
than actually doing it. Witness me, with several engine parts sitting
next to a lathe that's been idle for days, and last had an accessory for
a completely different engine built on it, not a part for the engine
that's half-done and sitting next to it.


Yep!
Tha's how it happens...


--

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

This isn't aviation related but this guy built a replica of a 1919
motorcycle. The info on the work involved is well worth reading...
http://www.flashbackfab.com/pages/excel00.html

Tony

On Tue, 9 Mar 2010 04:36:58 -0800 (PST), Jim Wilkins
wrote:

On Mar 8, 11:55Â*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.

"Peter Fairbrother" wrote

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?

You would think, but how they are designed is a major problem.

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.
--
Jim in NC