Moose: Tail Beef Up/Stinger/tail wheel pivot angle
Posted: Sat Feb 18, 2012 2:29 pm
I've seen this tailwheel (positive camber) argument before Ted from a couple
sources....and unfortunately disagree with it totally ! Running the
tailwheel positive camber makes for one twitchy ride, as as soon as you turn
that tailwheel slightly it will try to pass itself and turn around. Just try
hand pushing (forward) an airplane with a positively cambered tailwheel
using a tail wheel pull bar...turn the wheel about 45 degrees and see how
quickly it tries to ripe the pull bar out of your hands.
I shoot for a vertical pivot shaft/level pivot plate when lightly weighted
and of course this becomes a trailing (negative camber by attached link
drawing) tailwheel when loaded up. I still have the original tire on my
tailwheel going into 11 years now with virtually all it's tread....so there
is definitely no shimmy'ng going on back there.
Same deal with the MAM 1800 amphib nose wheels. Some owners have had shimmy
problems with them......pivot being dead nuts level.... and no way they will
trail on their own. Milling off a slight angle on the attach block so they
bolt on angled back with a "negative" caster stops all shimmy. If you went
positive camber like they are saying you would be worse off than a shopping
carts front wheels !
More food for thought!
I also don't understand this MAM came up with a beef up mod and isn't going
to make one part??? Think communication is X'd up somewhere!
Cheers,
Wayne
----- Original Message -----
From: "Ted Waltman" <tedwaltman@i1ci.com>
To: <rebel-builders@dcsol.com>
Sent: Friday, December 02, 2005 8:48 AM
Subject: Moose: Tail Beef Up/Stinger
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sources....and unfortunately disagree with it totally ! Running the
tailwheel positive camber makes for one twitchy ride, as as soon as you turn
that tailwheel slightly it will try to pass itself and turn around. Just try
hand pushing (forward) an airplane with a positively cambered tailwheel
using a tail wheel pull bar...turn the wheel about 45 degrees and see how
quickly it tries to ripe the pull bar out of your hands.
I shoot for a vertical pivot shaft/level pivot plate when lightly weighted
and of course this becomes a trailing (negative camber by attached link
drawing) tailwheel when loaded up. I still have the original tire on my
tailwheel going into 11 years now with virtually all it's tread....so there
is definitely no shimmy'ng going on back there.
Same deal with the MAM 1800 amphib nose wheels. Some owners have had shimmy
problems with them......pivot being dead nuts level.... and no way they will
trail on their own. Milling off a slight angle on the attach block so they
bolt on angled back with a "negative" caster stops all shimmy. If you went
positive camber like they are saying you would be worse off than a shopping
carts front wheels !
More food for thought!
I also don't understand this MAM came up with a beef up mod and isn't going
to make one part??? Think communication is X'd up somewhere!
Cheers,
Wayne
----- Original Message -----
From: "Ted Waltman" <tedwaltman@i1ci.com>
To: <rebel-builders@dcsol.com>
Sent: Friday, December 02, 2005 8:48 AM
Subject: Moose: Tail Beef Up/Stinger
Jeff,
The stinger mentioned by Steve is actually being designed and sold by
Dale Fultz, another member on the list. Dale has also created
significantly enhanced FUS-360 and FUS438L+R parts.
The new stinger will be created to the same specs as the prototype
stinger that I received from Murphy Aircraft and have in my plane now
for testing purposes. You can see a CAD diagram of the new stinger on
my webpage at http://www.i1ci.com/flying/Moose/Tail/TailUpgrade.html
The two possible differences--final design hasn't been confirmed
yet--are:
* Slightly longer round portion at the front end to allow for a two-bolt
attachment to FUS-360, as Dale's FUS-360 uses a larger attachment and
two bolts
* Different angle at the rear of the stinger, where the stinger inserts
into the swivel. The current prototype one that I have has a 9.5 degree
bend, which, if mounted in the second hole from the bottom of the Murphy
designed FUS-360, yields an adverse tailwheel/swivel angle as also seen
on my webpage. Hence, there is a debate going on as I write this to
determine what exact angle to bend the stinger at.
By the way, here is an excellent article on the theory and practice
behind the correct angle to have the tailwheel at:
http://merlin.alleg.edu//group/eaa1194/twshimmy.php. I encourage
everyone to read this great article and, in particular, to look at the
two images that accompany the article.
Ted Waltman
Moose 142SR
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Jeff McMurrer
Sent: Friday, December 02, 2005 12:12 AM
To: rebel-builders@dcsol.com
Subject: Re: Moose: Tail Beef Up/Stinger
Steve,
Could you tell me what the difference, if any, between your (group)
stinger and the MAM stinger, besides cost. Any specs, calculations?
Jeff
----- Original Message -----
From: Phillip Bohn <philbohn@ameritech.net>
Date: Thursday, December 1, 2005 3:56 pm
Subject: Re: Moose: Tail Beef Up
Steve,
Count us in for a new stinger as well.
Phil & Ted
Schaumburg, IL
Wes & Bobbi Jo Erb <lv2hike@gci.net> wrote:
Steve,
I could use a stinger as well if they fire up a producton line...
Thanks...
Wes Erb
Moose #208
Chugiak, AK
weserb@hotmail.com
Moose tail.----- Original Message -----
From: "Steve Halvorsen"
To:
Sent: Sunday, November 27, 2005 6:32 PM
Subject: Moose: Tail Beef Up
that youhim at:of thesupplied>> by MAM to do a correct install and make things easyier.
I will try to upbe leftway overand whensomeone whoproduction>> run to keep the cost down. The cost would be a lot
less than what MAM is--
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