The Murphy Builders Site

Or take the metronome off the piano, set it to 60 and blink your eyes in

with the metronome ... too many engineer types on this thread!
On 8/28/2006 7:59 PM, mkimball@gci.net wrote to rebel-builders:

-> I know the "check the tach" comment was a joke but it reminded me of a
-> quick, easy, cheap way of checking the tach on my Piper Arrow ages
ago. My
-> tach was placarded as reading 100RPM low and I was curious. I put some
duct
-> tape on the back of one of the blades on my two blade prop, waited for
night
-> to fall, then put the airplane near a light on a building with the tail
-> facing the building. In the US AC power is supplied at 60HZ so if my tach
-> is accurate, the blade with the tape will appear to stop at multiples

-> So I tried 1200, and 1800 RPM and discovered that, just as my tach was
-> placarded, my tach was off by 100 RPM. The prop appeared to stop at
1100
-> and 1700 RPM. If Canada is 50Hz then just use multiples of 50. Some
-> mechanic placarded my tach as reading 100RPM low and my test
confirmed it.
->
-> Mike
-> 044SR
->
-> -----Original Message-----
-> From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
-> Rebflyer@aol.com
-> Sent: Monday, August 28, 2006 4:45 AM
-> To: rebel-builders@dcsol.com
-> Subject: [rebel-builders] New Prop
->
-> Hi all,
-> Well it's time to admit I have now purchased prop #3. I vowed in the
-> beginning that I would not do that, but here I am anyway.
-> Short history is this. When first certified I installed a McCauley 76".
-> Great prop on wheels. It spun at about 2300 rpm on initial roll. I felt it
-> was
-> to coarse a pitch for the floats and it could not be repitched any more.
-> Then
-> came the Warp drive 3 blade sq tip 72". I really enjoyed that prop. I

-> that for almost 300 hrs prior to the cracks in the blade clamping area.
-> Pitched
-> for 2300 rpm on the initial roll it was a bit slow off the water for my
-> liking, but cruise ok. (as a side note, each 10 rpm change seemed to
relate
-> to 1
-> mph). Pitched for 2450 on the initial roll it smoked off the water,
-> especially light with cool temps( 60ish f) but 85mph for cruise.
-> I shipped the prop and hub back to Warp. For the cost of 1 blade they
-> sent
-> me a new hub and 4 blades. 70" sq tip. The performance from the 3 to
the 4
->
-> is the same as far as I could tell.
-> The rpm range on the Warps was about 600 rpm. More to come on this.
-> Well after waiting for 8 mo I now have a three blade 68" 46 pitch

-> prop. Very well known in the canard community for speed and

-> figured if it can take nuts, bolts and exhaust systems going thru the

-> without
-> catastrophic failure it should do fine on the front of a float plane.
-> After several conversations with Catto the numbers based on the engine
-> I'm
-> using and the hp it produces I decided on 2450 for the initial roll with
-> 125mph cruise at full throttle. 2750 rpm.
-> We hit those numbers right on the money. At 2450 it comes of the
water in
->
-> 90 deg f like the Warp did in 60 deg f !!! I can't wait till it gets

-> again! Cruise at full throttle shows 2775. 300 rpm range. I think I

->
-> check my tack(grin). Again in 90 deg f temps I'm indicating 115mph.

-> the
-> fastest I've been on floats. At 2500 it is very close to 100mph. We also
-> shot
-> for that number and hit it right on!
-> Out of all the differences between the props the one that I cannot

-> number to, but the seat of my pants and the size of the trees on the
-> shoreline
-> attest to, is when the floats break water this prop really keeps

-> Hard!
-> And last but not least unlike the warps It looks like a real prop!
-> So at this time the only complaint I have is the wait I had for the

->
-> It is better than I hoped for in performance!
-> Cost? 1775.00
-> More to come, but I'm going flying, so see ya later!
-> Curt N97MR
->
->
->
->
->
-> -----------------------------------------------------------------
-> List archives located at: https://www.dcsol.com/login
-> username "rebel" password "builder"
-> Unsubscribe: rebel-builders-unsubscribe@dcsol.com
-> List administrator: mike.davis@dcsol.com
-> -----------------------------------------------------------------
->
->
->





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->
-> -----Original Message-----
-> From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
-> Rebflyer@aol.com
-> Sent: Monday, August 28, 2006 4:45 AM
-> To: rebel-builders@dcsol.com
-> Subject: [rebel-builders] New Prop
->
-> Hi all,
-> Well it's time to admit I have now purchased prop #3. I vowed in the
-> beginning that I would not do that, but here I am anyway.
-> Short history is this. When first certified I installed a McCauley 76".
-> Great prop on wheels. It spun at about 2300 rpm on initial roll. I felt it
-> was
-> to coarse a pitch for the floats and it could not be repitched any more.
-> Then
-> came the Warp drive 3 blade sq tip 72". I really enjoyed that
prop. I flew
-> that for almost 300 hrs prior to the cracks in the blade clamping area.
-> Pitched
-> for 2300 rpm on the initial roll it was a bit slow off the water for my
-> liking, but cruise ok. (as a side note, each 10 rpm change seemed to
relate
-> to 1
-> mph). Pitched for 2450 on the initial roll it smoked off the water,
-> especially light with cool temps( 60ish f) but 85mph for cruise.
-> I shipped the prop and hub back to Warp. For the cost of 1 blade they
-> sent
-> me a new hub and 4 blades. 70" sq tip. The performance from the 3 to
the 4
->
-> is the same as far as I could tell.
-> The rpm range on the Warps was about 600 rpm. More to come on this.
-> Well after waiting for 8 mo I now have a three blade 68" 46 pitch Catto
-> prop. Very well known in the canard community for speed and durability. I
-> figured if it can take nuts, bolts and exhaust systems going thru
the prop
-> without
-> catastrophic failure it should do fine on the front of a float plane.
-> After several conversations with Catto the numbers based on the engine
-> I'm
-> using and the hp it produces I decided on 2450 for the initial roll with
-> 125mph cruise at full throttle. 2750 rpm.
-> We hit those numbers right on the money. At 2450 it comes of the
water in
->
-> 90 deg f like the Warp did in 60 deg f !!! I can't wait till it
gets cool
-> again! Cruise at full throttle shows 2775. 300 rpm range. I think
I need to
->
-> check my tack(grin). Again in 90 deg f temps I'm indicating
115mph. That's
-> the
-> fastest I've been on floats. At 2500 it is very close to 100mph. We also
-> shot
-> for that number and hit it right on!
-> Out of all the differences between the props the one that I cannot put a
-> number to, but the seat of my pants and the size of the trees on the
-> shoreline
-> attest to, is when the floats break water this prop really keeps pulling.
-> Hard!
-> And last but not least unlike the warps It looks like a real prop!
-> So at this time the only complaint I have is the wait I had for
the prop.
->
-> It is better than I hoped for in performance!
-> Cost? 1775.00
-> More to come, but I'm going flying, so see ya later!
-> Curt N97MR
->
->
->
->
->
-> -----------------------------------------------------------------
-> List archives located at: https://www.dcsol.com/login
-> username "rebel" password "builder"
-> Unsubscribe: rebel-builders-unsubscribe@dcsol.com
-> List administrator: mike.davis@dcsol.com
-> -----------------------------------------------------------------
->
->
->





-----------------------------------------------------------------
List archives located at: https://www.dcsol.com/login
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Unsubscribe: rebel-builders-unsubscribe@dcsol.com
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