Skis
Posted: Fri Feb 17, 2012 8:56 pm
Ski are well on the way, Wayne, time to rivet them up is the issue at the moment ---- building new houses-- buying more farms --- etc etc
Cheers
Alister
Cheers
Alister
winter or next)
It's not so much that they are so "involved", it's a matter of there being 2
beams instead of one like on a straight ski. The beams have to be located to
pick up inside and outside pivots and still have the tire centered in the
hole. That's what all the measuring is for! Two beams means more mfg time
(shearing, braking beams, etc), deburring, chromating, riveting etc and
installing the plastic bottms. Wheel skis are great if you hanger your
plane, like I do. I fly off a snow covered strip, but to get the Rebel back
into the hanger would be a nightmare with straight skis. I just land in the
snow, taxi over the snow bank onto my laneway and drive her right into the
hanger! If you are tied down outside, then straight skis would be fine if
you are right close to where the snow runway is.
Don't go buying new from Wagaero etc. unless you have money falling out of
your pockets and want to spend it! You should be able to pick up an old used
set of Federal (Fluidyne) A1500's for about $1500 CDN (skis seem to sell for
about a $1 Cdn/lb gross weight rating of the ski set). If you don't need
them this winter wait till spring and start looking/asking around then. Just
like you always buy floats in the fall, not in the spring when everyone
wants them! The axle size on most skis are set up for 1 1/2" axles. If you
have the 1 1/4" newer MAM axles a heavy rubber hose is enough to take up the
gap and large washers inside and out to keep the ski in place. IF using the
older 3/4" axles, I get a piece of 1 1/2" diameter Delrin Rod stock bored
with a 3/4" center hole, cut to fit the width of the pedestal, to adapt the
small axle to the ski.
1500's were originally made with bottoms about 8" wide. By now, after 40
years of use or so, the owner you will buy them from has put 10 or 12" wide
bottoms on them. This makes the 1500 ski a 2000 model. The beams don't
change in size between the 1500, 1800 and 2000. Try to get a set with
plastic on the bottoms, or you can paint with teflon paint. A set 12" wide
should keep you up pretty good in the snow. Won't be as good as my
penetration skis that are 21" wide at the nose and 18" at the back (they
have to be this wide due to the fact you are working around the width of the
tire and still need enough surface to rivet the beams to on each side), but
they should work great. I built them tapered to help with the ability to
turn around tighter, as the tails are narrower than the path that the nose
cuts. This allows you to swing tighter since the skis is not locked in the
track.
Regards,
Wayne G. O'Shea
www.irishfield.on.ca
----- Original Message -----
From: <Jims170A@cs.com>
To: <oifa@irishfield.on.ca>
Sent: Monday, December 17, 2001 2:26 PM
Subject: re: skis
wheelHi Wayne,
Thanks for such a fast and thorough response on the ski information!
I had no idea the wheel penetrating skis were so involved--sounds very
elaborate and labor intensive! I am thinking I will probably go with a
forreplacement ski similar to the Aero ski. I saw them listed in Wag-Aero
feetunder $2000US. I am not sure which size/width I would need to handle 2
amof powder. It would seem that bigger is better when it comes to skis; I
smallernot aware of any disadvantage of using big skis vs. smaller ones. You
mentioned a total of 18 sq ft of snow area, I am curious what is required
with wheel replacement skis (length/width).
Regarding the motor mount bolts, I have also been concerned about the
steel.size AN 4 bolts that are commonly used for the Jabiru 6 cyl. installation.
The mount supplied by Jabiru has a 5/8" bushing with a 1/4" bolt hole. I
have considered oversizing to 5/16" which would leave me with a wall
thickness of about 7/32". I am assuming the mount is made out of 4130
sideSo the real question is, where would the weak link be if I drill out to
5/16"? My gut feeling is that the weak link is probably on the airframe
Iwhere the two piece alluminum motor mount bracket is installed behind the
fire wall (regardless of NAS 4 bolt or AN 5 bolt). Anyway, at this point
mightstill plan on using an NAS 4 bolt to keep the wall thickness on the motor
mount bushing as supplied by Jabiru.
Well, again, thanks for all the information and the quick response. (I
didn't post this to the list, but feel free to pass it on to anyone it
help.)
Hope you get some good flying weather soon,
Jim
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