shock and c.s.props

[Geert Frank]

Hi again. A builder called me yesterday. He shall remain nameless. He now
has 8 flying hours on his Rebel. I am not supposed to do capital letters in
my e.mail, but that was too much: HE CLAIMS HIS FLAPERON TORQUE TUBE(S) ARE
TWISTING! What is worse he claims that he found five other Rebel owners
"with the same condition". This is what he does: he clamps one outer
flaperon flush with the inner wing tip or let someone hold it tight in that
position.... he goes to the opposite side outer flaperon and claims he can
get full travel up and full travel down on that flaperon. I told him no way
and I tried it on my Rebel and all I got was a few degrees movement because
of "slop". I suspect he is getting aileron activity because of those round
pieces being press fit into their torque tube segment. There is/are one or
two round pieces that have not been rivetted through those HD rivets around
the circumference of the tube(s). When he does his little test he now
overcomes the existing press fit friction and is able to do what he does. I
told him to ground his aircraft until he found the problem. His answer was "
well there are five others that have the same condition". Please guys, I am
not making this up. Maybe the man is having me on as they say in jolly old
England. Comments?
I too have been waiting for some good reports on a c.s.prop that can be used
and be priced within reason. The QuintiAvio prop (Italian at SNF) is
currently being tested on a 2.5 liter Subaru Legacy. So far fantastic
things, but it will cost $ 3900 no spinner and no backplate. I also want to
humbly point out that there is far less vibration on automotive conversions
than on "regular" engines, so that cannot be the reason for those alleged
failures. I say again, there are certainly some drawbacks on automotive
conversions, mostly economic ones i.e. purchase not so cheap after all,
re-sale value, etc. but vibration is not one of the drawbacks. I also talked
to a guy in Holland who must have dared to deal with NSI (he went to the
factory I think) and has 175 hours on a 1000cc BMW (motorcycle conversion)
with one of their c.s. props. happier than the proverbial clam. That thing
is putting out 100 hp on some plan built two-seater. I think that too much
horsepower(torque) is what make for the initial problems with these c.s.
props. Although it sounds like the makers are doing something about fixing
the problems. Curious that for example NSI and I think the Italians also,
will let you use the Warp Drive blades to be used in their hubs, yet Warp
Drive gave up on the c.s. prop after a nasty failure some years ago. At
least so I was told. Geert Frank

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[rebelair]

Hi Geert

I read your email with great interest. I don't understand at all any part
of the Rebel that relies upon a press fit. Are you suggesting that they did
not rivet the aluminium plug into the 2" torque tube?

Brian #328R

-----Original Message-----
From: Geert Frank [mailto:storchpilot@mediaone.net]
Sent: Sunday, May 21, 2000 10:23 AM
To: murphy archives
Cc: Bob Grenier
Subject: shock and c.s.props


Hi again. A builder called me yesterday. He shall remain nameless. He now
has 8 flying hours on his Rebel. I am not supposed to do capital letters in
my e.mail, but that was too much: HE CLAIMS HIS FLAPERON TORQUE TUBE(S) ARE
TWISTING! What is worse he claims that he found five other Rebel owners
"with the same condition". This is what he does: he clamps one outer
flaperon flush with the inner wing tip or let someone hold it tight in that
position.... he goes to the opposite side outer flaperon and claims he can
get full travel up and full travel down on that flaperon. I told him no way
and I tried it on my Rebel and all I got was a few degrees movement because
of "slop". I suspect he is getting aileron activity because of those round
pieces being press fit into their torque tube segment. There is/are one or
two round pieces that have not been rivetted through those HD rivets around
the circumference of the tube(s). When he does his little test he now
overcomes the existing press fit friction and is able to do what he does. I
told him to ground his aircraft until he found the problem. His answer was "
well there are five others that have the same condition". Please guys, I am
not making this up. Maybe the man is having me on as they say in jolly old
England. Comments?
I too have been waiting for some good reports on a c.s.prop that can be used
and be priced within reason. The QuintiAvio prop (Italian at SNF) is
currently being tested on a 2.5 liter Subaru Legacy. So far fantastic
things, but it will cost $ 3900 no spinner and no backplate. I also want to
humbly point out that there is far less vibration on automotive conversions
than on "regular" engines, so that cannot be the reason for those alleged
failures. I say again, there are certainly some drawbacks on automotive
conversions, mostly economic ones i.e. purchase not so cheap after all,
re-sale value, etc. but vibration is not one of the drawbacks. I also talked
to a guy in Holland who must have dared to deal with NSI (he went to the
factory I think) and has 175 hours on a 1000cc BMW (motorcycle conversion)
with one of their c.s. props. happier than the proverbial clam. That thing
is putting out 100 hp on some plan built two-seater. I think that too much
horsepower(torque) is what make for the initial problems with these c.s.
props. Although it sounds like the makers are doing something about fixing
the problems. Curious that for example NSI and I think the Italians also,
will let you use the Warp Drive blades to be used in their hubs, yet Warp
Drive gave up on the c.s. prop after a nasty failure some years ago. At
least so I was told. Geert Frank

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[Bob Patterson]

Geert,
You could be right !! There's certainly NO way the torque tubes
could TWIST enough to give FULL DEFLECTION !!

I certainly hope this builder DOES check to see if one of the
plugs is not rivetted in !! This could be VERY SERIOUS !!!!!

Please keep us updated on results with this Italian prop. There
definitely is a LARGE market here, waiting for the RIGHT prop !!

.....bobp

--------------------------------orig.--------------------------------------
At 10:22 AM 5/21/00 -0400, you wrote:

Hi again. A builder called me yesterday. He shall remain nameless. He now
has 8 flying hours on his Rebel. I am not supposed to do capital letters in
my e.mail, but that was too much: HE CLAIMS HIS FLAPERON TORQUE TUBE(S) ARE
TWISTING! What is worse he claims that he found five other Rebel owners
"with the same condition". This is what he does: he clamps one outer
flaperon flush with the inner wing tip or let someone hold it tight in that
position.... he goes to the opposite side outer flaperon and claims he can
get full travel up and full travel down on that flaperon. I told him no way
and I tried it on my Rebel and all I got was a few degrees movement because
of "slop". I suspect he is getting aileron activity because of those round
pieces being press fit into their torque tube segment. There is/are one or
two round pieces that have not been rivetted through those HD rivets around
the circumference of the tube(s). When he does his little test he now
overcomes the existing press fit friction and is able to do what he does. I
told him to ground his aircraft until he found the problem. His answer was "
well there are five others that have the same condition". Please guys, I am
not making this up. Maybe the man is having me on as they say in jolly old
England. Comments?
I too have been waiting for some good reports on a c.s.prop that can be used
and be priced within reason. The QuintiAvio prop (Italian at SNF) is
currently being tested on a 2.5 liter Subaru Legacy. So far fantastic
things, but it will cost $ 3900 no spinner and no backplate. I also want to
humbly point out that there is far less vibration on automotive conversions
than on "regular" engines, so that cannot be the reason for those alleged
failures. I say again, there are certainly some drawbacks on automotive
conversions, mostly economic ones i.e. purchase not so cheap after all,
re-sale value, etc. but vibration is not one of the drawbacks. I also talked
to a guy in Holland who must have dared to deal with NSI (he went to the
factory I think) and has 175 hours on a 1000cc BMW (motorcycle conversion)
with one of their c.s. props. happier than the proverbial clam. That thing
is putting out 100 hp on some plan built two-seater. I think that too much
horsepower(torque) is what make for the initial problems with these c.s.
props. Although it sounds like the makers are doing something about fixing
the problems. Curious that for example NSI and I think the Italians also,
will let you use the Warp Drive blades to be used in their hubs, yet Warp
Drive gave up on the c.s. prop after a nasty failure some years ago. At
least so I was told. Geert Frank

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