Rebel Fin Offset
Posted: Fri Feb 17, 2012 10:13 pm
Terry, mine is offset the original 1/2" MAM spelled out and something has
always made it turn left anyhow. Tried various things knowing deep down it
was a difference in wing incidence (that isn't adjustable!) and gave up
playing and just put a trim tab (piece of my first windshield!) on the
outboard right flaperon to fix it. All the ones I've built since that had
the wings set exactly the same using a digital level and ZERO fin offset and
they fly perfectly straight (and would do so all the way across the
country!). I would mount the fin straight and like you say hold a bit of
right rudder on take off, it you need it. If it needs a bit of rudder in
flight just tighten up the spring on the rudder pedal in need!
No reason you can't use bolts for the attach of the fin. Don't see why you
want to increase the shear strength by 5 though (about 400lbs/rivet for
RV1613 rivets vs 2126lb/bolt for AN3 bolt) and someone will have to crawl
down and hold the nuts for you.
Wayne
----- Original Message -----
From: "Terry Dazey"
To: "Wayne O'Shea"
Sent: Tuesday, June 18, 2002 3:02 PM
Subject: Rebel Fin Offset
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always made it turn left anyhow. Tried various things knowing deep down it
was a difference in wing incidence (that isn't adjustable!) and gave up
playing and just put a trim tab (piece of my first windshield!) on the
outboard right flaperon to fix it. All the ones I've built since that had
the wings set exactly the same using a digital level and ZERO fin offset and
they fly perfectly straight (and would do so all the way across the
country!). I would mount the fin straight and like you say hold a bit of
right rudder on take off, it you need it. If it needs a bit of rudder in
flight just tighten up the spring on the rudder pedal in need!
No reason you can't use bolts for the attach of the fin. Don't see why you
want to increase the shear strength by 5 though (about 400lbs/rivet for
RV1613 rivets vs 2126lb/bolt for AN3 bolt) and someone will have to crawl
down and hold the nuts for you.
Wayne
----- Original Message -----
From: "Terry Dazey"
To: "Wayne O'Shea"
Sent: Tuesday, June 18, 2002 3:02 PM
Subject: Rebel Fin Offset
Hello Wayne:
This has been brought up before. Unfortunately the dcsol system is down
or I would have posted this to the group.
I am getting conflicting thoughts on what the fin offset should be. The
newsgorup archive consensus is that there is NO need for offset, but the
MAM manual says to offset it 3/4 inch. Seems like it would be easier to
install the fin with zero degrees instead of making wedge shims. I would
rather kick in a little rudder on climb out and have the aircraft fly
straight an level at cruise.
Who do I believe? What is your opinion since you have flown/built
numerous Rebels with (I imagine) numerous configurations?
Also, is it okay to use 9 AN3-X bolts, nuts & washers at the forward fin
attach tabs (the ones that go through the one piece bulkhead & doubler)?
I am going to run an O-320 on amphib floats if that makes a difference.
Thanks in advance for any advice on this topic.
Your Pilot Pal,
Terry Dazey
Rebel 662
Seattle, Washington
PS: As soon as Mike gets the newsgroup up-and-running again, I will
modify and post this message to them also.
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