Lycoming engine fails! Pilot survives!

On Mon, 24 Nov 2003 22:40:13 GMT, Roger Halstead
wrote:


Who is the guy near Lakeland that uses, or used the Aluminum small
block Chevy in the Lancair IV-P? Think it was just shy of 400 cu
inch.

He did a lot of testing including dyno work.
After he had the front web separate on take off he went out and
purchased the equipment to cast his own blocks. He figured the front
web was too weak to take the PSRU stresses.

I talked to him at Oshkosh a few years back and he figured that he had
over 7 figures into the engine operation at that time.
Admittedly there are few of us who can afford to do that, but he was
developing a lot of useful information the rest of us could, or might
be able to use.

He had flown the rig to Oshkosh from Lakeland in about 3 hours, so
that sucker did haul. Don't know about engine life and durability
though.

You'll have to fix the return add due to dumb virus checkers, not spam
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com

That would be Jim Rahm of Enginair. In a former life he was the no. 2
guy behind "HURST" as in Hurst shifters. Auto's and hotrodding were
his life, until he discovered aviation. Hotrodding an airplane just
seemed a natural to him.

You're right, the engine had a LOT of engineering and dyno development
and so far has performed flawlessly. The PSRU on the other hand, has
been problematic. The PSRU was the one thing he felt should be done
by people who knew how to do them, and contracted NIS to develop one.

To make a long story short, the PSRU did not work well and things have
been in litigation for a while. Making a PSRU to handle 120 to 180
horsepower is one thing, making one to handle over 400 horsepower is
something entirely different.

Corky Scott

On Mon, 01 Dec 2003 17:20:55 GMT,
(Corky Scott) wrote:

The PSRU was the one thing he felt should be done
by people who knew how to do them, and contracted NIS to develop one.

To make a long story short, the PSRU did not work well and things have
been in litigation for a while. Making a PSRU to handle 120 to 180
horsepower is one thing, making one to handle over 400 horsepower is
something entirely different.

Corky Scott

Sorry, that should be NSI.

Corky Scott

On Tue, 02 Dec 2003 12:57:49 GMT,
(Corky Scott) wrote:

On Mon, 01 Dec 2003 17:20:55 GMT,
(Corky Scott) wrote:

The PSRU was the one thing he felt should be done
by people who knew how to do them, and contracted NIS to develop one.

To make a long story short, the PSRU did not work well and things have
been in litigation for a while. Making a PSRU to handle 120 to 180
horsepower is one thing, making one to handle over 400 horsepower is
something entirely different.

Corky Scott


Thanks Corky,

I appreciate the info.
As I see it (and I don't know squat about PSRUs except their goal) a
high ratio PSRU as used in a turbo prop which has a very high ratio
(planetary) is easier to build than say the 2:1 or 3:1, BUT the
planetary also has the advantage in being used on an engine without
pulses being inherent in their operation.

The life of a PSRU on a piston engine has to be complicated. It not
only has to handle linear torque and thrust, but virtually any other
imaginable angle as well. Then it has to be designed to avoid any
resonances with those power train pulses AND take the positive and
negative torque without beating the snot out of the gears which means
next to nothing for slack (which brings its own set of problems).
Helical, double helical, spur, planatery...each with it's own set of
pluses and minuses.

BUT, didn't the big 12 and 16 cylinder Vs in WWII have PSRUs? Course
those engines had very short TBOs too. Then again they weren't
exactly babied either.

Also...How did the guys make out using the Olds chain drive in the
Legend? It "appeared" to work great for at least a short time, but
they were running 400 to 500 HP through a chain that was used in a
drive train that only had about 200 HP on the other end. When I
talked to the one guy at Oshkosh some years back he thought it had
plenty of reserve.
I always like that airplane. Last I saw it had a turbine up front.

Sorry, that should be NSI.

I know when he used the original "so called" chevy big block aluminum
based engine he felt the front web was the weak spot. Course that was
right after planting his IV_P off the end of the runway when the web
broke. (or did he make it back on that one?) At any rate the web
broke and it was a high pucker factor.

That sucker sure did go though. The only thing that would have been
able to beat him from Lakeland to Oshkosh would have been a jet and it
would have had to have been a direct, non stop flight.

You'll have to fix the return add due to dumb virus checkers, not spam
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com

Corky Scott

On Wed, 03 Dec 2003 02:05:35 GMT, Roger Halstead
wrote:


The life of a PSRU on a piston engine has to be complicated. It not
only has to handle linear torque and thrust, but virtually any other
imaginable angle as well. Then it has to be designed to avoid any
resonances with those power train pulses AND take the positive and
negative torque without beating the snot out of the gears which means
next to nothing for slack (which brings its own set of problems).
Helical, double helical, spur, planatery...each with it's own set of
pluses and minuses.

Most manufacturers seem to take the attitude that big is strong and
bigger is stronger. In order to resist the impulses and resonances
you mention, they just design huge gears to take the load.

BUT, didn't the big 12 and 16 cylinder Vs in WWII have PSRUs? Course
those engines had very short TBOs too. Then again they weren't
exactly babied either.

Yup, the Roll Royce Merlin uses a spur gear reduction drive, driven
off a torque tube. Those gears are some big. Every single one of the
big radials also used a reduction drive, but was a planetary type, not
spur. I think the low TBO was more due to the nature of the treatment
of the engine during combat than something inherent in the design.
But come to think of it, they still don't have a very high TBO even
now, when they don't have to be run up to military power for every
takeoff.

By the way, the Rolls Royce Griffon engine was sort of two 12 cylinder
engines siamesed together for a total of 24 cylinders. I'd hate to
work on that thing.

Also...How did the guys make out using the Olds chain drive in the
Legend? It "appeared" to work great for at least a short time, but
they were running 400 to 500 HP through a chain that was used in a
drive train that only had about 200 HP on the other end. When I
talked to the one guy at Oshkosh some years back he thought it had
plenty of reserve.
I always like that airplane. Last I saw it had a turbine up front.

Sorry, that should be NSI.

I know when he used the original "so called" chevy big block aluminum
based engine he felt the front web was the weak spot. Course that was
right after planting his IV_P off the end of the runway when the web
broke. (or did he make it back on that one?) At any rate the web
broke and it was a high pucker factor.

I hadn't heard that the web broke. The story I got was that they did
some computer analysis of the engine design and factored in the prop
forces that would be transferred to the block by the PSRU and decided
to add material to the block where the PSRU bolted on. Of course, Jim
could have told me this AFTER the engine broke, don't know.

Corky Scott

"Corky Scott" wrote in message
...
On Wed, 03 Dec 2003 02:05:35 GMT, Roger Halstead
wrote:


The life of a PSRU on a piston engine has to be complicated. It not
only has to handle linear torque and thrust, but virtually any other
imaginable angle as well. Then it has to be designed to avoid any
resonances with those power train pulses AND take the positive and
negative torque without beating the snot out of the gears which means
next to nothing for slack (which brings its own set of problems).
Helical, double helical, spur, planatery...each with it's own set of
pluses and minuses.

Most manufacturers seem to take the attitude that big is strong and
bigger is stronger. In order to resist the impulses and resonances
you mention, they just design huge gears to take the load.

BUT, didn't the big 12 and 16 cylinder Vs in WWII have PSRUs? Course
those engines had very short TBOs too. Then again they weren't
exactly babied either.

Yup, the Roll Royce Merlin uses a spur gear reduction drive, driven
off a torque tube. Those gears are some big. Every single one of the
big radials also used a reduction drive, but was a planetary type, not
spur. I think the low TBO was more due to the nature of the treatment
of the engine during combat than something inherent in the design.
But come to think of it, they still don't have a very high TBO even
now, when they don't have to be run up to military power for every
takeoff.

By the way, the Rolls Royce Griffon engine was sort of two 12 cylinder
engines siamesed together for a total of 24 cylinders. I'd hate to
work on that thing.

Also...How did the guys make out using the Olds chain drive in the
Legend? It "appeared" to work great for at least a short time, but
they were running 400 to 500 HP through a chain that was used in a
drive train that only had about 200 HP on the other end. When I
talked to the one guy at Oshkosh some years back he thought it had
plenty of reserve.
I always like that airplane. Last I saw it had a turbine up front.

Sorry, that should be NSI.

I know when he used the original "so called" chevy big block aluminum
based engine he felt the front web was the weak spot. Course that was
right after planting his IV_P off the end of the runway when the web
broke. (or did he make it back on that one?) At any rate the web
broke and it was a high pucker factor.

I hadn't heard that the web broke. The story I got was that they did
some computer analysis of the engine design and factored in the prop
forces that would be transferred to the block by the PSRU and decided
to add material to the block where the PSRU bolted on. Of course, Jim
could have told me this AFTER the engine broke, don't know.

Corky Scott
Corky,
Sorry, but the Griffon was a V-12 like the Merlin, just BIGGER:

http://www.home.aone.net.au/shack_one/rolls.htm

Rick Pellicciotti
http://www.spitfire.org

Rick Pellicciotti wrote:

"Corky Scott" wrote in message
...
On Wed, 03 Dec 2003 02:05:35 GMT, Roger Halstead
wrote:


The life of a PSRU on a piston engine has to be complicated. It not
only has to handle linear torque and thrust, but virtually any other
imaginable angle as well. Then it has to be designed to avoid any
resonances with those power train pulses AND take the positive and
negative torque without beating the snot out of the gears which means
next to nothing for slack (which brings its own set of problems).
Helical, double helical, spur, planatery...each with it's own set of
pluses and minuses.

Most manufacturers seem to take the attitude that big is strong and
bigger is stronger. In order to resist the impulses and resonances
you mention, they just design huge gears to take the load.

BUT, didn't the big 12 and 16 cylinder Vs in WWII have PSRUs? Course
those engines had very short TBOs too. Then again they weren't
exactly babied either.

Yup, the Roll Royce Merlin uses a spur gear reduction drive, driven
off a torque tube. Those gears are some big. Every single one of the
big radials also used a reduction drive, but was a planetary type, not
spur. I think the low TBO was more due to the nature of the treatment
of the engine during combat than something inherent in the design.
But come to think of it, they still don't have a very high TBO even
now, when they don't have to be run up to military power for every
takeoff.

By the way, the Rolls Royce Griffon engine was sort of two 12 cylinder
engines siamesed together for a total of 24 cylinders. I'd hate to
work on that thing.

Also...How did the guys make out using the Olds chain drive in the
Legend? It "appeared" to work great for at least a short time, but
they were running 400 to 500 HP through a chain that was used in a
drive train that only had about 200 HP on the other end. When I
talked to the one guy at Oshkosh some years back he thought it had
plenty of reserve.
I always like that airplane. Last I saw it had a turbine up front.

Sorry, that should be NSI.

I know when he used the original "so called" chevy big block aluminum
based engine he felt the front web was the weak spot. Course that was
right after planting his IV_P off the end of the runway when the web
broke. (or did he make it back on that one?) At any rate the web
broke and it was a high pucker factor.

I hadn't heard that the web broke. The story I got was that they did
some computer analysis of the engine design and factored in the prop
forces that would be transferred to the block by the PSRU and decided
to add material to the block where the PSRU bolted on. Of course, Jim
could have told me this AFTER the engine broke, don't know.

Corky Scott
Corky,
Sorry, but the Griffon was a V-12 like the Merlin, just BIGGER:

http://www.home.aone.net.au/shack_one/rolls.htm

Rick Pellicciotti
http://www.spitfire.org

However, there were at least two variants of Rolls Royce Griffon engines:
1 On the Spitfire, it had a single five bladed propeller which
rotated in the reverse direction from the propeller on the
Merlin engined aircraft. I have been told that it killed a few
unwary pilots who forgot and pressed the wrong rudder pedal on
take-off. :-(
2 On the Lancaster, and on at least one single engined attack
aircraft (I can't recall the name), it was equipped with a pair
of concentric contra-rotating propellers. As you say, though,
the engine itself was similar but BIGGER.

Regards,

Peter

On Wed, 03 Dec 2003 15:13:03 GMT, Peter Dohm
wrote:


However, there were at least two variants of Rolls Royce Griffon engines:
1 On the Spitfire, it had a single five bladed propeller which
rotated in the reverse direction from the propeller on the
Merlin engined aircraft.




I have been told that it killed a few
unwary pilots who forgot and pressed the wrong rudder pedal on
take-off. :-(

Regards,

Peter
++++++++++++++++++++++++++++++++

Really.

Who told you such?
Sounds like wannabee myth and legend
without some serious documentation.


Barnyard BOb - over 50 years of successful flight

On Wed, 3 Dec 2003 08:27:25 -0600, "Rick Pellicciotti"
wrote:


Sorry, but the Griffon was a V-12 like the Merlin, just BIGGER:

http://www.home.aone.net.au/shack_one/rolls.htm

Rick Pellicciotti
http://www.spitfire.org


Sorry, my bad. I was thinking of the Napier Sabre type H engine.

It was used in the Typhoon and Tempest.

See: http://www.eagle.ca/~harry/aircraft/tempest/sabre/

Corky Scott

"Corky Scott" wrote in message
...
On Wed, 3 Dec 2003 08:27:25 -0600, "Rick Pellicciotti"
wrote:


Sorry, but the Griffon was a V-12 like the Merlin, just BIGGER:

http://www.home.aone.net.au/shack_one/rolls.htm

Rick Pellicciotti
http://www.spitfire.org


Sorry, my bad. I was thinking of the Napier Sabre type H engine.

It was used in the Typhoon and Tempest.

See: http://www.eagle.ca/~harry/aircraft/tempest/sabre/

Corky Scott

Yes, that was a manly engine if there ever was one.

Rick

Roger

Merlin (in P-51) turned 3000 rpm on take off. Prop speed was 1500 rpm
(2 to 1 reduction gearing).

Engine life was about 250+/- hrs (not in combat).

Probably happened but never heard of the reduction gearing 'going
west'. Was not a 'common' failure mode to be worrried about.

Big John


On Wed, 03 Dec 2003 02:05:35 GMT, Roger Halstead
wrote:

On Tue, 02 Dec 2003 12:57:49 GMT,
(Corky Scott) wrote:

On Mon, 01 Dec 2003 17:20:55 GMT,
(Corky Scott) wrote:

The PSRU was the one thing he felt should be done
by people who knew how to do them, and contracted NIS to develop one.

To make a long story short, the PSRU did not work well and things have
been in litigation for a while. Making a PSRU to handle 120 to 180
horsepower is one thing, making one to handle over 400 horsepower is
something entirely different.

Corky Scott


Thanks Corky,

I appreciate the info.
As I see it (and I don't know squat about PSRUs except their goal) a
high ratio PSRU as used in a turbo prop which has a very high ratio
(planetary) is easier to build than say the 2:1 or 3:1, BUT the
planetary also has the advantage in being used on an engine without
pulses being inherent in their operation.

The life of a PSRU on a piston engine has to be complicated. It not
only has to handle linear torque and thrust, but virtually any other
imaginable angle as well. Then it has to be designed to avoid any
resonances with those power train pulses AND take the positive and
negative torque without beating the snot out of the gears which means
next to nothing for slack (which brings its own set of problems).
Helical, double helical, spur, planatery...each with it's own set of
pluses and minuses.

BUT, didn't the big 12 and 16 cylinder Vs in WWII have PSRUs? Course
those engines had very short TBOs too. Then again they weren't
exactly babied either.

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