The Murphy Builders Site

Hello,
I spoke with Mark Landoll, the gentleman that sells a harmonic dampener
for the Lycoming/Warp drive set-up. My call was to get some information
on the mounting arrangement that is used for his product. His dampener
is bolted to the 12 holes around the outside of the engine flywheel.
With the 10 pound weight of the dampener, I am concerned with the
ability for the flywheel to remain intact for any extended period if the
dampener is bolted to it. The flywheel is made of a cast aluminum and
does not have a very thick cross section. I've got to believe that
Lycoming has substantial engineering data and years of operating
experience that established the cross sectional thickness for the
fywheel. Attaching an additional 10 lbs. to it's periphery might give
you a great big surprise some day. As I have said in the past, even
before the Warp Drive blade cracking became an issue, I believe at this
point the best avenue for me is to bite the bullet and go for the
Sensenich metal prop take the additionl 10 lb penalty and write off the
additional $1000.00 (approx) as cheap life insurance (wife agrees). The
prop dampener may be a fine product and I am in no way putting down the
product but in my opinion you will definitly be venturing into the
"experimental" black hole and as always "the choice is yours". My reason
for providing this information is that from previous posts to this site
some people seem to think that a prop dampener of some kind will solve
all of the problems associated with the aforementioned blade cracking
and idleing problems and I caution them about the concequences of such
experimentation and you should question everything and anything that
goes onto/into your aircraft.
Believe it or not, I have been wrong before! And maybe I'm way off about
my concern of the additional 10 lbs. on the flywheel and I sure would
like some comments from others regarding this matter. What are the
recommended Sensenitch prop size/pitches for O-320 150HP Rebels on wheels?
Thanks to all,
Rick D.




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Rick,

I hear you, as all that flywheel is designed for is to start the engine
(nothing else, except a timing mark location!). It is not designed for the
centrifugal force of a weight bolted onto it! (although it does have that
steel ring pressed on around the outside to possibly hold it all together!).
I think there have been lots of Marks dampners flying for years though (I
THINK) with no reports of crumbling starter flywheels.

The prop I have been using with great success (that Bob and Howard have on
their Rebels) is the Sensenich 74DM7S8-0-56. Bob's has the -56 pitch and
works great. Howard went with a -52 to be a little finer for float
operation, but definitely suffers because of it in cruise.

I purchased these Propellors NEW through MAM to get the OEM pricing (almost
$3000 Cdn with gst). If you buy NEW from a local dealer, the price will be
about 50% more! These propellors c/w spacer & mount bolts weigh in at 40
pounds. The numbers are broken down as 74 = 74" diameter, DM is the
blade/model style, the 7 = 7/16" bolts (so you may need a 6 = 3/8"!?), S =
spacer and the 8 = 8/4ths or 2" spacer thickness (you may need different to
match your cowling set up), Have no frig'n idea what the 0 stands for and
the 56 of course is the pitch!

Good Luck,
Wayne G. O'Shea
www.irishfield.on.ca

----- Original Message -----
From: "Rick DeCiero" <rsdec1@star.net>
To: <murphy-rebel@dcsol.com>
Sent: Saturday, March 24, 2001 1:17 PM
Subject: Prop dampeners


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Hello,
I spoke with Mark Landoll, the gentleman that sells a harmonic dampener
for the Lycoming/Warp drive set-up. My call was to get some information
on the mounting arrangement that is used for his product. His dampener
is bolted to the 12 holes around the outside of the engine flywheel.
With the 10 pound weight of the dampener, I am concerned with the
ability for the flywheel to remain intact for any extended period if the
dampener is bolted to it. The flywheel is made of a cast aluminum and
does not have a very thick cross section. I've got to believe that
Lycoming has substantial engineering data and years of operating
experience that established the cross sectional thickness for the
fywheel. Attaching an additional 10 lbs. to it's periphery might give
you a great big surprise some day. As I have said in the past, even
before the Warp Drive blade cracking became an issue, I believe at this
point the best avenue for me is to bite the bullet and go for the
Sensenich metal prop take the additionl 10 lb penalty and write off the
additional $1000.00 (approx) as cheap life insurance (wife agrees). The
prop dampener may be a fine product and I am in no way putting down the
product but in my opinion you will definitly be venturing into the
"experimental" black hole and as always "the choice is yours". My reason
for providing this information is that from previous posts to this site
some people seem to think that a prop dampener of some kind will solve
all of the problems associated with the aforementioned blade cracking
and idleing problems and I caution them about the concequences of such
experimentation and you should question everything and anything that
goes onto/into your aircraft.
Believe it or not, I have been wrong before! And maybe I'm way off about
my concern of the additional 10 lbs. on the flywheel and I sure would
like some comments from others regarding this matter. What are the
recommended Sensenitch prop size/pitches for O-320 150HP Rebels on

wheels?

Thanks to all,
Rick D.

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Just to add one more thing for those of you thinking of going the dampener
route, please check your flywheel before ordering one! I just checked on the
four (4) lycomings that I have in the hanger. Two of them have the 12 holes
in the flywheel. One has the cast locations for such holes, but no holes are
there and the 4th doesn't even have the locations cast on the flywheel.

Wayne

----- Original Message -----
From: "Rick DeCiero" <rsdec1@star.net>
To: <murphy-rebel@dcsol.com>
Sent: Saturday, March 24, 2001 1:17 PM
Subject: Prop dampeners


*-------------------------------------------------------------------------*

The list archives are located at:
http://www.dcsol.com:81/public/default.htm
username: rebel password: builder

*-------------------------------------------------------------------------*

Hello,
I spoke with Mark Landoll, the gentleman that sells a harmonic dampener
for the Lycoming/Warp drive set-up. My call was to get some information
on the mounting arrangement that is used for his product. His dampener
is bolted to the 12 holes around the outside of the engine flywheel.
With the 10 pound weight of the dampener, I am concerned with the
ability for the flywheel to remain intact for any extended period if the
dampener is bolted to it. The flywheel is made of a cast aluminum and
does not have a very thick cross section. I've got to believe that
Lycoming has substantial engineering data and years of operating
experience that established the cross sectional thickness for the
fywheel. Attaching an additional 10 lbs. to it's periphery might give
you a great big surprise some day. As I have said in the past, even
before the Warp Drive blade cracking became an issue, I believe at this
point the best avenue for me is to bite the bullet and go for the
Sensenich metal prop take the additionl 10 lb penalty and write off the
additional $1000.00 (approx) as cheap life insurance (wife agrees). The
prop dampener may be a fine product and I am in no way putting down the
product but in my opinion you will definitly be venturing into the
"experimental" black hole and as always "the choice is yours". My reason
for providing this information is that from previous posts to this site
some people seem to think that a prop dampener of some kind will solve
all of the problems associated with the aforementioned blade cracking
and idleing problems and I caution them about the concequences of such
experimentation and you should question everything and anything that
goes onto/into your aircraft.
Believe it or not, I have been wrong before! And maybe I'm way off about
my concern of the additional 10 lbs. on the flywheel and I sure would
like some comments from others regarding this matter. What are the
recommended Sensenitch prop size/pitches for O-320 150HP Rebels on

wheels?

Thanks to all,
Rick D.

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Wayne,
As always Wayne, thanks for the reply and all of the Sensenich info. I
will be contacting MAC next week for some pricing etc. The proposed
canidate for U.S./Canadian ambassador lives a few streets away from me
here in Hudson, MA, maybe he can cut a good deal for me on a prop from
MAC. I had already mounted my cowling with the warp drive set up and a
2" spacer. Maybe there will not be too much rework reqiured.
Also, don't forget that the flywheel spins the alternator via a belt.
Still trying to complete the fuel delivery system. I found some great
little shut off ball valves at Home depot, $4.99 each. They are forged
brass, 1/4" pipe thread with all teflon seals, a blowout proof stem,
full ports(5/16" min hole) and light weight. They had a part number on
them 107-701HC and are a Mueller Industries (B&K) valve. I recearched
them on the Mueller website and they appear to be a high quality valve.
They are about 1" long and are a very compact package.
Any other comments out there?
Rick D.





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