Hello all,
Have been quite surprised by 2 recect messages, which I would like opinion on.
The first is attached below, and simply requires builders to countersink a
hole through the spar from 5mm on one wing to 15 mm on the other. Now I
measured my spar and it appears to be 30 mm thick, or thereabouts. So to
accomodate the length of bolt supplied we builders have to countersink using
a "19mm spadebit" ( a BIG hole!), a further 10 mm to a depth of 1/2 the
spar. Now maybe I am misunderstanding something, and if so someone please
tell me, politely will be fine ( I get the message pretty quickly), but
wouldn't a longer bolt fix this problem! I feel this puts me in quite a
dilemna, as my Overseeing/Statutory Authority will not let me do other than
what is in the manual, and such a divergence would be considered more than
as described in the manual as "slightly deeper". (This is not "double" the
depth otherwise it would say so, let alone "triple" the recommended depth!)
I request the manual be ammended to incorporate such a divergence, or a new
component to rectify this anomoly, or at the very least a newsletter
reference to authenticate such a procedure, implying company backing of the
removal of such a large amount of spar, no doubt with due consideration for
such a significant structural mod.
The second topic was the one where a factory endorsed fix for a short rudder
was to slice the fuselage in several locations and pull it up to match the
rudder. The only opinion I have read about this method was very well put,
and in my opinion quite restrained, something to do with a kitchen table.
. I want to know if this is a common occurence or not? If so, it would beg
the simple question" why", which I am most keen to know as it will simply
tell me if my efforts today were in vain!
Excerpt No.1
Re: Your time over again??? Rudder fit.
From: europa aviation ltd <enquiries@avnet.co.uk>
Subject: Re: Bolt Lengths
>In mounting the quick connect bellcranks to the wing, I found that the port
>bolt seems too short unless the counterbore is substantially deeper than the
>5mm specified. I calculate the bolt lengths required as follows:
>
> Port Stbd
>
>Spar 1.256 1.276 Includes 3 layers of bid added
>each side
>S03 1.273
>3 Washers .173 .173
>BC4W10 .560 .560
>Nut .210 .210
>2 Threads .050 .050
> -.200 -.200 Counterbore reduces length
>required
> ------ -------
> 3.322 2.069
>The bolts supplied were: port = AN4-31A, stbd = AN4-20A. The port bolt
>supplied is 0.2in shorter than I expected while the starboard bolt agrees
>with the calculated length. In practice, the starboard bolt is fine and the
>port bolt does not go all the way through the nut. The manual indicates that
>the port counterbore may need to be slightly deeper that the starboard
>counterbore, possibly to accommodate this.
>>So, has anyone else run into this? I am hesitant to double the depth of the
>counterbore since this seems more than "slightly" deeper. Bob Berube says I
>am the only one who has called about this (probably because I am a first time
>builder so I don't have a sense of what might cause trouble later so I try to
>err on the side of conservatism).
>>In the same area, what is the typical clearance between the bolt ends holding
>the wing mounted bellcrank vs the CS14 mounted bellcrank? I have less than
>0.1in on the stbd side. Might these come in contact as the wings are inserted
>or will the lift pins prevent this?
>
>xxxx
>
In answer to your concern about the counterbore depth for the AN4-31A bolt,
you will need to counterbore to a depth of around 15mm, which I agree is
more than "slightly deeper than 5mm".
The pivot bolts of CS15 and W16 do end up very close to each other. Some
clearance is necessary, of course.
You may find that the bolt end of CS15's pivot will contact the edge of the
spar mounted bellcrank W16 unless the aileron is held in its neutral
position when rigging or derigging the wings.
Regards
xxxx-------------------------------------
Excerpt No. 2.
Thanks for your message regarding your similar problem with an undersized
rudder and Andy's claim that they had never experienced the problem before ...
Ah ha!! You might be interested to know that Europa Aviation (US side) had the
same problem with their tri-gear! I seem to recall Bob Berube telling me they
refashioned the top of the rudder too.
Hi xxxx
You wrote "When I trial fitted my rudder, it was too short by about half inch."
Glad to hear someone else had this interesting situation. When I telephoned Andy
& subsequently sent him some photos I was told I was the only one with this as
far as he was aware.
I took the alternative approach to this (after discussion with Andy) and raised
the bottom of the fuselage by cutting three long (200mmish), narrow wedge slots
in it - one at the bottom and one either side at approx. 60 degrees up from
bottom one, or whatever looks right.
After some fiddling and fixing, the "banana'd" back end is then pulled up to the
bottom of the rudder and glassed up on both sides. Will need some filling and
profiling soon.
Think I prefer your method though.
Regards,
xxxxx
ANY OPINIONS/VIEWS/ADVICE???
P.S. I would like to be able to uplink without always sticking my head up?
How do I do this?
P.S.S. Sorry about the length of message!
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