Hi Bud
I have been following with interest this problem because whilst I was
building my Europa I became very unhappy with the design which required
a degree of precision machining and fitting that was not available to
the average builder - me.
I overcame the problem with mod 11969 which replaced the TP14 pins with
close tolerance bolts which when tightened up on to a shaped nut plate
mounted inside the torque tube clamped everything together so removing
any chance of fretting taking place. There is little or no tube
distortion and as I had to rig test my design in order to gain LAA
approval, found that with all the bolts torque up to 200 lbs inches the
assembly could transmit 90 lbs ft before slipping. No glue, no
hammering.
I would appreciate your opinion on this mod.
Regards
Richard Collings
----- Original Message -----
From: Bud Yerly
To: europa-list@matronics.com
Sent: Sunday, October 14, 2012 11:40 PM
Subject: Re: Europa-List: Re: Mod 73
Pete and Bob
Had the same kind of idea. Putting a slotted tube bored for the pins
and use flush riveted nutplates in the tube with bolts to clamp the
tubes together. Install by sliding in the nutplated tube and aligning
the holes. However, that still will distort the tubes when the bolts
are turned down making removal almost impossible as in tapered pins. My
other idea was an expanding bolt. A 1/4 inch bolt with a steel insert
in the center and two bronze bushings at the ends so that as the bolt is
tightened, the bronze expands like a rivet and fills the small gap,
making it tight. My A&P said, why not just rivet it in place. Just
change the stab to allow it to rotate a full 90 degrees to allow
riveting.
However, what we have works, is maintainable and can be assembled by
amateurs using drift pins and bolts (which allow a loose fit) during
assembly and allows for a solid install provided the holes and pins are
correctly sized for zero clearance.
Good ideas though,
Bud
----- Original Message -----
From: Pete
To: europa-list@matronics.com
Sent: Sunday, October 14, 2012 5:51 PM
Subject: Re: Europa-List: Re: Mod 73
Thinking out loud here, what about very accurately machining
substantive internal bolt bushings (made of a material to not cause
galvanic corrosion), tap them all the way down the tube to their proper
location, then bolt tight the two tubes without fear of distortion?
Just throwing it out there,
Cheers,
Pete
On Oct 14, 2012, at 4:47 PM, "Bob Harrison" <ptag.dev@tiscali.co.uk>
wrote:
You could drill and thread the heads of the parallel pins and use
a bolt to Jack the out if needed.
Regards
Bob Harrison G-PTAG
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of GRAHAM
SINGLETON
Sent: 14 October 2012 18:14
To: europa-list@matronics.com
Subject: Re: Europa-List: Re: Mod 73
No, they would distort the torque tube which must be perfectly
circular
Graham
-------------------------------------------------------------------------
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From: Pete <peterz@zutrasoft.com>
To: "europa-list@matronics.com" <europa-list@matronics.com>
Sent: Sunday, 14 October 2012, 14:04
Subject: Re: Europa-List: Re: Mod 73
I fully understand the requirement for an interference pin fit to
avoid the hammering out of the holes over time.
That said, could "taper pins" be used?
cheers,
Pete
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