Robt.C.Harrison
-----Original Message-----
From: R.C.Harrison [mailto:ptag.dev@tiscali.co.uk]
Subject: RE: Europa-List: Tri-gear adjustment, fireproof resin, carbon
fiber strips
Hi! Steve.
I have raised this question a number of times but any "fix" is likely to
be a costly exercise in design and consequent cost let alone official
approval.
IMHO since the original Europa Concept was a Monowheel with retract
facility the trike became an add on quick fix since it wasn't expected
to be so popular. I even built G-PTAG as a "convertible" intending to
revert to Mono when I had completed flight training. In my case I don't
think it will ever become a priority for me to convert to the Mono
configuration. Again IMHO the toe in of the stub axles in the build
alignment method doesn't make any allowances for the loads of the wings,
un-useable fuel, and pilot since in the process none of these items are
present and so reacting on the gear legs. It would be however a complete
disaster should you finish up with toe out whilst trying to make
allowances. It needs some experimentation undertaking to find an optimum
location for castor and toe and parallel settings to be discovered.
I have encouraged a friend to try to achieve the best possible position
and I know he has made an effort but there will have had to be a
compromise since should the cured alignment be unsatisfactory it would
be an extensive rip out to start over. My experience has not been good
with at least 3 sets of tyres in say 650 hours. (But I have changed my
tyres last with a harder compound and to date they seem to be holding
out better.)
Concerning a fix for future adjustment my thoughts have centred around a
"U" bolt clamping arrangement by application of "U " bolts through the
3/4" ply fillets, and a method of an adjustable cap on top of the legs.
This cap would be available as a range of caps with the drillings for
the legs made rotationally in 1 degree spacings over say a 3 degree
range or perhaps with research even less since 1/2 degree would
translate into a massive change to the toe in settings.
Alternatively the location holes in the top of the gear legs could be
radially slotted enabling a range of inserts to be engaged with
differing radial alignments of the location bolt. However the available
metal in the top of the gear legs is very limited for this concept.
IMHO this matter is of considerable importance when reviewed in the
light of an excessive toe in producing additional drag in the take off
run as well as unreasonable tyre wear.
However the question of bending the legs is a complete "NO NO" IMHO.
They are made of spring steel and considerable research would need
applying with regards to heat treatment prior to bending and after
bending.
They are immensely strong since as a bystander I saw my a/c bounce to a
height of some 12 ft when loaded "two POB" on an alleged wind shear
situation on test. They bent, without permanent yield, so far as to
split the fibre glass fairings wide open in two locations over their
lengths.
Of course tire wear is not an item of concern if you always fly from
grass!
I also recommend that you closely examine the suitability of the tube
supplied with the nose wheel, lightly inflate the tube in the tyre
without the wheel hub and ensure there is no creases since I have
suffered two failures clearly showing crease marks due to the tube being
3.5" cross section diameter when a 3" CROSS SECTION IS NEEDED.
Regards
Bob Harrison G-PTAG Europa MKI/Jabiru 3300
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of SteveD
Subject: Europa-List: Tri-gear adjustment, fireproof resin, carbon fiber
strips
1. I am building a motor-glider tri-gear and have been concerned about
adjustments to the tri-gear main gear arms. Once the sockets are molded
in (even assuming I get them at the correct angle) the only way to
adjust them if not correct initially or if perchance I made a rough
landing (very small probability) is to bend the arms - this seems less
than optimal. I have designed a way to adjust the main gear arms using a
larger diameter tube bonded to the the X-bracing and then adjust the
socket within this - it would be some work but would give me the ability
to adjust toe-in and toe-out and distance between the wheels. My
questions is - is alignment a real problem - in talking with Clift Shaw
(who I met in a castle in Ireland) - it appears he had a problem wearing
out tires in the first hundred and some hours - so is it worth the
effort to be able to align the main gear arms, given that the load is
always different - any help from those that are flying trigears?
2. I am building the plane with the Hi-Top mod- but don't have the
Hi-Top
bottom canoe - so I need to build up the sides (I am making this piece
as per the factory instructions) - and need to build up the firewall
also. Any sources for fireproof resin?
3. I wanted to reinforce some areas using 2" or so strips of carbon
fiber - any sources for finished carbon fiber - I would rather not have
to learn how to work with carbon fiber cloth.
Thanks
Gary Leinberger
Lancaster, Pa.
A237
P.S. This Email has my address because I was upgrading the forum, and I
stepped on Gary's post.
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