DIY Two-Stroke Engine Construction Methods

Garry O wrote:
"Garry O" wrote in message
u...
"Tim Wescott" wrote in message
...
frank wrote:
On Mar 10, 9:02 pm, Rufus wrote:
durabol wrote:
The two main methods for homebuilt construction would be casting vs.
machining or some combination of both (probably the best option).
Forging probably isn't appropriate for home construction (either the

-- snip --

like a motorcycle engine - strip it down and just build the parts and
accessories required to make it turn a prop. And along the way one
can
also machine it's component parts down to lighten it...run it on the
ground, if it breaks, you know you went too far.

--
- Rufus (pilot, engineer, jeweler, model builder...yadda,
yadda...)

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

The FAA licensing process for homebuilts is much lighter weight than
for 'regular' aircraft. People can and do convert automotive engines
for homebuilts, and fly them. There are many building processes that
aren't certified for general aviation, but which are acceptable to
the FAA inspectors for homebuilts.

Check the EAA website (eaa.org?) -- they'll have something.


www.faa.gov the eaa is a pilot organisation, not a controling
authotiry :-)

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


and I must remember to read what is written after the first coffee of
the day 'DOH
your correct, the EAA will have a lot of information on homebuilt and
experimental A/C, they will also want you to get regular inspections
during the construction, even on experimental I think, and at various
benchmarks during the build.
personally I wouldn't fly with any home made engine, and by home made
I'm talking about things like casting your own cylinders etc, why
re-invent the wheel when there is a plethora of R&D'd engines that can
more easily and cheaply be converted.

My feeling was that while the FAA will give you enough rules to make a
swamp, the EAA will give you a map of the swamp so you can get through it!

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

frank wrote:
On Mar 10, 9:02 pm, Rufus wrote:
durabol wrote:
The two main methods for homebuilt construction would be casting vs.
machining or some combination of both (probably the best option).
Forging probably isn't appropriate for home construction (either the
piston or connecting rod).
One method I have thought of is to produce a wax model of the engine
with molds (to a fairly high tolerance to minimize machining) which is
then cast using lost wax casting techniques. I planned to have an
integral cylinder head/cylinder/half the crank case (this is for an
opposed style engine). The only bolts would be to bolt the two halves
together.
As someone whom has done lost wax casting, I wouldn't recommend doing
that for something I was going to bet my life on...not without investing
LARGE amounts of capital in equipment - a centrifugal or pressure
injection foundry...sand casting (which I've also done) is a far better
alternative for casting a raw engine casing. Make a durable wooden
master model, preferably of a hardwood.

In any event, you're still going to have to sleeve the cylinders with
some alloy of machined, durable steel - which will have to be hardened
and polished in some way and interference fit into the block or stud.
And you need to match coefficients of thermal expansion when choosing
your materials in order to keep it all tight - same goes for choosing
and tolerancing your bolts and every other component in direct
contact...which means you also need to do some thermal analysis and
figure out how hot, as well as how, your engine is going to run...

A completely machined engine would need a large block of aluminium to
start with which I'm not sure how practical that would be. Perhaps
lost foam casting could be used as a general model of the engine was
made in foam and then cast and the resulting casting could be
machined.
Brock
Again - big investment in big machines to insure uniformity of the
casting...which will kill the project (and the pilot) if you screw it
up. Hot spots, porosity, voids...not that simple. Best way to
spot/find/quality check castings involve die penetrant or x-ray.

Also - don't overlook the fact that you are going to have to heat treat,
case harden, or otherwise machine or post-work any part you produce
depending on choice and application of materials...I don't know what
kind of tools and resources the OP has at hand, but if he's starting
from scratch he better be prepared to spend the amount of money he'd
spend on a mid-size car in tooling just to get started with such a
project...make it a large luxury car, now that I think about it...

The far easier (and safer) alternative is to modify an existing engine -
like a motorcycle engine - strip it down and just build the parts and
accessories required to make it turn a prop. And along the way one can
also machine it's component parts down to lighten it...run it on the
ground, if it breaks, you know you went too far.

--
- Rufus (pilot, engineer, jeweler, model builder...yadda, yadda...)

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

Depends on the Category, I think. But yeah...that's yet another mess I
wouldn't really want to have to tackle either!

--
- Rufus

Jim Stewart wrote:
cavelamb wrote:
frank wrote:

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.


When did this start???

It didn't. Experimental class is still around
and my friend still flies a VW engined plane.

That's a heavier aircraft than an ultralight...not sure what they do
with ultralights, or light sport...anybody know about certs for those
two Categories/Classes?

--
- Rufus

jan olieslagers wrote:
cavelamb schreef:
What? This?

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

This is completely false!

The sheer fact that he implies the FAA has worldwide authority shows he
doesn't know what he is talking about. Least said soonest forgotten.

....maybe he meant FAI?..still..

--
- Rufus

On Thu, 11 Mar 2010 17:55:30 -0800, Rufus wrote:

Jim Stewart wrote:
cavelamb wrote:
frank wrote:

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.


When did this start???

It didn't. Experimental class is still around
and my friend still flies a VW engined plane.

That's a heavier aircraft than an ultralight...not sure what they do
with ultralights, or light sport...anybody know about certs for those
two Categories/Classes?
Ultralight in the USA is totally unregulated other than needing to be
rediculously light. The new sport aviation class I am not sure of -
but I do know certified engines are not required for all. Here in
Canada a class called "advanced ultralight" has some regulation - but
still no certified engine requirement.
Our "Amateur built" class has no engine certification requirements or
limits.

"Tim Wescott" wrote in message
...
Garry O wrote:
"Garry O" wrote in message
u...
"Tim Wescott" wrote in message
...
frank wrote:
On Mar 10, 9:02 pm, Rufus wrote:
durabol wrote:
The two main methods for homebuilt construction would be casting vs.
machining or some combination of both (probably the best option).
Forging probably isn't appropriate for home construction (either the

-- snip --

like a motorcycle engine - strip it down and just build the parts and
accessories required to make it turn a prop. And along the way one
can
also machine it's component parts down to lighten it...run it on the
ground, if it breaks, you know you went too far.

--
- Rufus (pilot, engineer, jeweler, model builder...yadda,
yadda...)

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

The FAA licensing process for homebuilts is much lighter weight than
for 'regular' aircraft. People can and do convert automotive engines
for homebuilts, and fly them. There are many building processes that
aren't certified for general aviation, but which are acceptable to the
FAA inspectors for homebuilts.

Check the EAA website (eaa.org?) -- they'll have something.


www.faa.gov the eaa is a pilot organisation, not a controling authotiry
:-)

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


and I must remember to read what is written after the first coffee of the
day 'DOH
your correct, the EAA will have a lot of information on homebuilt and
experimental A/C, they will also want you to get regular inspections
during the construction, even on experimental I think, and at various
benchmarks during the build.
personally I wouldn't fly with any home made engine, and by home made I'm
talking about things like casting your own cylinders etc, why re-invent
the wheel when there is a plethora of R&D'd engines that can more easily
and cheaply be converted.

My feeling was that while the FAA will give you enough rules to make a
swamp, the EAA will give you a map of the swamp so you can get through it!

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

If the FAA is anything like CASA down here your 100% correct :-)

--
Remember Altitude is more important than Attitude

not sure what they do with ultralights, or light sport...

LSA in the US (and any country that adopted these rules, I presume)
require their engines to comply with the industry standard ASTM F 2339
"Standard Practice for Design and Manufacture of Reciprocating Spark
Ignition Engines for Light Sport Aircraft". This it not an FAA
certification.

Oliver

On Thu, 11 Mar 2010 07:20:47 -0600, cavelamb wrote:
frank wrote:

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.


When did this start???

First recorded case I recall was some young punk named Icarus...





grin

--
It is the business of education to implant insight and respon-
sibility. It must turn irresponsible opinion into responsible
judgement and lead from chance and arbitrariness to the rational
lucidity of an intellectual order. -- Mies Van der Rohe
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all)

Frnak McKenney wrote:
On Thu, 11 Mar 2010 07:20:47 -0600, cavelamb wrote:
frank wrote:
Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

When did this start???

First recorded case I recall was some young punk named Icarus...





grin



No, this is mis-information.

The statement that anything that flies has to be certified by FAA is
categorically incorrect - as several have pointed out here.

Homebuilts are not certified at all.
Not approved, either.

a certificate of airworthiness is is not the same thing as a certified
design. Actually, the correct term is certificated, not certified.

The statements that started all this (top) i believe are from the model
community(?). They are certainly not from someone why knows anything
about experimental amateur built aircraft.


--

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

Oliver Arend wrote:
not sure what they do with ultralights, or light sport...

LSA in the US (and any country that adopted these rules, I presume)
require their engines to comply with the industry standard ASTM F 2339
"Standard Practice for Design and Manufacture of Reciprocating Spark
Ignition Engines for Light Sport Aircraft". This it not an FAA
certification.

Here's the actual cite from F2245-09:

7.2 Engines—Installed engines shall conform to Practice
F 2339 or Practice F 2538 or shall be type certificated or
otherwise approved under FAR-33, JAR-E, or JAR-22 Subpart
H standards.

And you are correct, it is not an FAA
certification.