Oh those CERTIFIED plane engines !!!!!!!!!!!!!!!!!

This is Mark Hickey's profile...........

Geez, ya think he's a pilot?????

Most people I know that love bicycles are TREE HUGGERS and hate powered
things. Like we didn't figure that out on the previous posts you made..


The Veep's shooting spree. rec.bicycles.tech moments ago
Oh those CERTIFIED plane engines !!!!!!!!!!!!!!!!!
rec.aviation.homebuilt moments ago
Making Motorcycle Engines Fly... Litterally. rec.motorcycles.tech
7 hours ago
Bike Fit rec.bicycles.tech 7 hours ago
Road Tires. rec.bicycles.tech 7 hours ago
The Veep's shooting spree. rec.bicycles.tech 8 hours ago
The Bikes of China rec.bicycles.misc 8 hours ago
Oh those CERTIFIED plane engines !!!!!!!!!!!!!!!!!
rec.aviation.homebuilt 8 hours ago
how long must threaded fork be to make it threadless
rec.bicycles.tech 41 hours ago
The Veep's shooting spree. rec.bicycles.tech 41 hours ago

stol wrote:
For all you guys and gals building a homebuilt plane DO NOT use a auto
engine conversion or any other option that is not FAA certified, Ya see
the feds and Lycoming have a lock on the market providing "quality and
time tested powerplants". Let's see now. it all started a few years
back when Lycoming had a brain fart and decided they knew more about
crankshafts then god, so they redid them, with the FAA's blessing of
course. Ya know the feds demand strict safety testing and "high"
quality control over certified parts. Well, that batch of hundreds had
several break and kill a few innocent souls, So they recalled them and
redesigned the problem out of them and in the meantime kept hundrends
of planes grounded for months while they " patched" the issue. They
introduced a "New and Improved" crank that would cure all their issues.
Well, those broke at a alarming rate and killed 14 innocent souls. All
the while with the feds watching this all unfold. Lycoming then tried
to sue the forging company that stamped out the cranks that THEY speced
the design for. Well, that didn't fly either.


So here comes round number three. Too bad they don't have the three
strike rule in aviation..

http://www.lycoming.textron.com/supp...tins/SB569.pdf

Ben
www.haaspowerair.com

ya, I am the bad guy trying to get ol Barnyard Blob to wake up. G

I've got a reason for delaying any decision regarding a kit or the
engine. TBOs asice, theres the basic reliability factor. I'm not
comnfortable with the current options based on the remote areas I would
plan to go.

i know there aren't that many engine failures, but I have a magnetic
draw to Murphy. He'd certainly be my passenger running somewhere
between Calgary and Anchorage.

wrote:

...

Hollow shafts are stiffer than solid shafts. The stresses are
all concentrated in the outside wall, with no central material to act
as a fulcrum to stretch the outside on bends. Try bending a piece of
5/8" bar and one of 5/8" tube sometime (same material, of course) and
see the difference. The bar will bend, but the tube will resist bending
until it suddenly kinks. Cranks need to be stiff, especially where they
are loaded with gyroscopic forces, and need to be light, so they're
mostly hollow.


More importantly a hollow shaft that is the same weight as a solid
one will have a larger diameter which gives you much better
stiffness, especially in torsion, for the same weight.

--

FF

Richard Lamb wrote:
RapidRonnie wrote:

Bottom line is that if you use an auto engine made in the millions you
can research the failure rate, particularly if you pick an engine used
in motorsports run to destruction you can see where they fail first. I
would pay a premium, a big premium, to be able to fly a small block
Chevy in terms of a bigger airframe than you otherwise would, just for
that huge knowledge base.


Gently disagree, Ron.

The reason is that the prop loads are far different from anything you'll
see on the race track.


If I may be forgiven (or not) for reading about the Corvair crank
failures with rectal vision, they should not have surprised anyone.

I have never heard of anyone breaking the crankshat in their family
car,
that includes VWs. That tells me that auto manufacturers in general
and VW in particular have sucessfully designed their cranks to last
indefinately under nominal and even somewhat more adverse than
nominal conditions.

One supposes, however, that auto manufacturers do not make the
crank a whole lot stronger than needed to achieve that result.
A part that lasts indefinately is not improved by making it last
longer than indefinately when doing so would add weight which,
especially to a high RPM moving part, is generally a bad idea.

There are a lot of VW powered airplanes, and it is not uncommon
for the crankshaft to break in those.

If we make the unremarkable assumption that GM did not over-
design their Corvair crankshats any more than VW did theirs then
the Corvair crankshaft failures are quite predictable.

It is highly unlikely that any auto manufacturer is going to put
a crankshaft that is a whole lot stronger than needed into a
standard engine, don't you think?

--

FF

wrote:
wrote:
...

Hollow shafts are stiffer than solid shafts. The stresses are
all concentrated in the outside wall, with no central material to act
as a fulcrum to stretch the outside on bends. Try bending a piece of
5/8" bar and one of 5/8" tube sometime (same material, of course) and
see the difference. The bar will bend, but the tube will resist bending
until it suddenly kinks. Cranks need to be stiff, especially where they
are loaded with gyroscopic forces, and need to be light, so they're
mostly hollow.


More importantly a hollow shaft that is the same weight as a solid
one will have a larger diameter which gives you much better
stiffness, especially in torsion, for the same weight.

Yes. The outer diameter of the hollow tube will be slightly larger than
the solid rod. On the drawing board, if the outer diameter is strictly
limited (by crank journal diameter), or slightly limited (if the block
allows slightly larger journals), then changing the crankshaft from
solid for hollow this may or may not be an issue. (Pretty wordy!)

In reality, swapping out a solid crankshaft for a hollow one of equal or
at least sufficient strength and stiffness is not always simple,
prudent, or even possible. (Pretty wordy again!)

Here is a good reference for anyone (regardless of their level of
engineering knowledge):

http://www.engineersedge.com/calcula...re_case_12.htm

You can play with the numbers a bit. Moment of inertia is directly
related to stiffness (in torsion) while (cross section) area is directly
related to weight. Section modulus is directly related to bending strength.


PS- Fred, you (and others in this thread) obviously have a good handle
on this stuff. My post is mostly directed to the audience. Disclaimer,
I'm 99% sure I got the working definitions right. Corrections are
welcome

In article .com,
wrote:

Richard Lamb wrote:
RapidRonnie wrote:

Bottom line is that if you use an auto engine made in the millions you
can research the failure rate, particularly if you pick an engine used
in motorsports run to destruction you can see where they fail first. I
would pay a premium, a big premium, to be able to fly a small block
Chevy in terms of a bigger airframe than you otherwise would, just for
that huge knowledge base.


Gently disagree, Ron.

The reason is that the prop loads are far different from anything you'll
see on the race track.


If I may be forgiven (or not) for reading about the Corvair crank
failures with rectal vision, they should not have surprised anyone.

I have never heard of anyone breaking the crankshat in their family
car,
that includes VWs. That tells me that auto manufacturers in general
and VW in particular have sucessfully designed their cranks to last
indefinately under nominal and even somewhat more adverse than
nominal conditions.

One supposes, however, that auto manufacturers do not make the
crank a whole lot stronger than needed to achieve that result.
A part that lasts indefinately is not improved by making it last
longer than indefinately when doing so would add weight which,
especially to a high RPM moving part, is generally a bad idea.

There are a lot of VW powered airplanes, and it is not uncommon
for the crankshaft to break in those.

If we make the unremarkable assumption that GM did not over-
design their Corvair crankshats any more than VW did theirs then
the Corvair crankshaft failures are quite predictable.

It is highly unlikely that any auto manufacturer is going to put
a crankshaft that is a whole lot stronger than needed into a
standard engine, don't you think?

Automotive crankshafts are designed to take loads in predominately
torquing modes, while aircraft crankshafts have to take bending and
thrust loads, due to the fact that they have a very large flywheel
hanging on the end, which resists changes in direction.

Either engine will work quite nicely for the purpose for which it was
intended. It is when you change the mission that you had better
understand how the mission changes the operating environment vs the
design parameters.

Orval Fairbairn wrote:
In article .com,
wrote:


Richard Lamb wrote:

RapidRonnie wrote:


Bottom line is that if you use an auto engine made in the millions you
can research the failure rate, particularly if you pick an engine used
in motorsports run to destruction you can see where they fail first. I
would pay a premium, a big premium, to be able to fly a small block
Chevy in terms of a bigger airframe than you otherwise would, just for
that huge knowledge base.


Gently disagree, Ron.

The reason is that the prop loads are far different from anything you'll
see on the race track.


If I may be forgiven (or not) for reading about the Corvair crank
failures with rectal vision, they should not have surprised anyone.

I have never heard of anyone breaking the crankshat in their family
car,
that includes VWs. That tells me that auto manufacturers in general
and VW in particular have sucessfully designed their cranks to last
indefinately under nominal and even somewhat more adverse than
nominal conditions.

One supposes, however, that auto manufacturers do not make the
crank a whole lot stronger than needed to achieve that result.
A part that lasts indefinately is not improved by making it last
longer than indefinately when doing so would add weight which,
especially to a high RPM moving part, is generally a bad idea.

There are a lot of VW powered airplanes, and it is not uncommon
for the crankshaft to break in those.

If we make the unremarkable assumption that GM did not over-
design their Corvair crankshats any more than VW did theirs then
the Corvair crankshaft failures are quite predictable.

It is highly unlikely that any auto manufacturer is going to put
a crankshaft that is a whole lot stronger than needed into a
standard engine, don't you think?


Automotive crankshafts are designed to take loads in predominately
torquing modes, while aircraft crankshafts have to take bending and
thrust loads, due to the fact that they have a very large flywheel
hanging on the end, which resists changes in direction.

Either engine will work quite nicely for the purpose for which it was
intended. It is when you change the mission that you had better
understand how the mission changes the operating environment vs the
design parameters.

And, as Orval had likely experienced himself,
(dam long limber chain drives?)
PSRU's may take the gyroscopic forces out,
but can add harmonic resonance issues that
may be even tougher to deal with than a simple
broken crank shaft...

It all looks so easy on paper...

Richard

wrote

If I may be forgiven (or not) for reading about the Corvair crank
failures with rectal vision, they should not have surprised anyone.

If you would read the site again, I think you will find that the breaking
problem is limited to higher speed airplanes, not stuff like aircampers,
right?

It is highly unlikely that any auto manufacturer is going to put
a crankshaft that is a whole lot stronger than needed into a
standard engine, don't you think?

Some manufacturers, at certain times in their lifespan, are less comfortable
with cutting design strength margins too closely. GM is more likely to
build hell for stout, than are many of the imports, IMHO.
--
Jim in NC

On Sun, 5 Mar 2006 14:22:07 -0500, "Morgans"
wrote:


wrote

If I may be forgiven (or not) for reading about the Corvair crank
failures with rectal vision, they should not have surprised anyone.

If you would read the site again, I think you will find that the breaking
problem is limited to higher speed airplanes, not stuff like aircampers,
right?

It is highly unlikely that any auto manufacturer is going to put
a crankshaft that is a whole lot stronger than needed into a
standard engine, don't you think?

Some manufacturers, at certain times in their lifespan, are less comfortable
with cutting design strength margins too closely. GM is more likely to
build hell for stout, than are many of the imports, IMHO.

And even more than the "aircraft" manufacturers, where weight IS the
enemy, and where change for improvement's sake is very much frowned
upon. If you change or improve something, you are admitting something
was less than perfect, and leaving yourself vulnerable to that
"unwashed horde" known as the "legal proffesion".

*** Free account sponsored by SecureIX.com ***
*** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com ***

In article t,
Richard Lamb wrote:

Orval Fairbairn wrote:
In article .com,
wrote:


Richard Lamb wrote:

RapidRonnie wrote:


Bottom line is that if you use an auto engine made in the millions you
can research the failure rate, particularly if you pick an engine used
in motorsports run to destruction you can see where they fail first. I
would pay a premium, a big premium, to be able to fly a small block
Chevy in terms of a bigger airframe than you otherwise would, just for
that huge knowledge base.


Gently disagree, Ron.

The reason is that the prop loads are far different from anything you'll
see on the race track.


If I may be forgiven (or not) for reading about the Corvair crank
failures with rectal vision, they should not have surprised anyone.

I have never heard of anyone breaking the crankshat in their family
car,
that includes VWs. That tells me that auto manufacturers in general
and VW in particular have sucessfully designed their cranks to last
indefinately under nominal and even somewhat more adverse than
nominal conditions.

One supposes, however, that auto manufacturers do not make the
crank a whole lot stronger than needed to achieve that result.
A part that lasts indefinately is not improved by making it last
longer than indefinately when doing so would add weight which,
especially to a high RPM moving part, is generally a bad idea.

There are a lot of VW powered airplanes, and it is not uncommon
for the crankshaft to break in those.

If we make the unremarkable assumption that GM did not over-
design their Corvair crankshats any more than VW did theirs then
the Corvair crankshaft failures are quite predictable.

It is highly unlikely that any auto manufacturer is going to put
a crankshaft that is a whole lot stronger than needed into a
standard engine, don't you think?


Automotive crankshafts are designed to take loads in predominately
torquing modes, while aircraft crankshafts have to take bending and
thrust loads, due to the fact that they have a very large flywheel
hanging on the end, which resists changes in direction.

Either engine will work quite nicely for the purpose for which it was
intended. It is when you change the mission that you had better
understand how the mission changes the operating environment vs the
design parameters.

And, as Orval had likely experienced himself,
(dam long limber chain drives?)
PSRU's may take the gyroscopic forces out,
but can add harmonic resonance issues that
may be even tougher to deal with than a simple
broken crank shaft...

It all looks so easy on paper...

I didn't experience it myself, but I have witnessed a few less than
spectacular results. One was a Ford V-6 in a Mustang II -- very poor
job, V-belt broke and took out the ignition -- fatal.

Another two were in Stewart 51s: one was a Ford V-8 with full electronic
fuel injection, etc. The computer took awhile to set up for high power,
then took awhile for low power. It got some bent valves. Owner replaced
it with a Walther turbine after only four flights.

Another S-51 had a chain drive PSRU, which started eating up the PSRU
housing because of chain slop -- there were no tensioners on the chain.

I have also seen a few successes, too. One was the late George Morse's
Olds V-6 in his Skybolt and later in the Prowler. He found that you need
an AN water pump instead of the automotive one and that you also need a
coolant pressure indicator, in addition to temperature.

Another success (so far) is an S-51 with a V-8 (geared PSRU) that ahs
been flying here for about a year. I don't know what problems (if any)
he has had, but he is taking small steps.

As I posted earlier, you CAN fly, successfully, on automotive
conversions, but it is not for the novice and technically-inexperienced.