Rowland, I am appalled/alarmed to hear that each aileron has gained
something like 1.5 lbs. I would suggest a couple of things - firstly do
a surface area calculation and work out how much weight the whole
aircraft is due to gain with current paint system, and secondly sand it
off one aileron and get Roger Targett to gel coat it, rub it down to
that perfect laminar flow finish and see how much that has added. The
great thing about gel coat is that you remove most of it, rubbing down
with wet and dry sandpaper. My gel coated 914 XS is one of the lightest
on the register and it is not because of lack of kit! I would have done
some calculations myself but I have the dominant cat sitting on my lap
and he would be most offended if I went to measure things up! My mental
guesstimation though is that the ailerons have probably a bit less than
2% of total area, so you may be looking at your paint adding 100lbs,
which seems a fairly serious issue.
Regards, David Joyce, GXSDJ
On 2017-08-29 17:56, William Daniell wrote:
> Rowland.
>
> When I balanced mine - admittedly I had not shaved anything off the top - I
> not
only had to drill a 1/2" hole, I practically had to hollow out the weights
to get them to balance per the manual. It was a very annoying job with the drill
bit catching on the lead etc. I read from the forum that this is quite common.
>
> So it surprises me that yours balance TE down.... perhaps some pics of your
> aileron
balance horn and the box into which it fits might be helpful.
>
> Will
>
> William Daniell LONGPORT
>
> +57 310 295 0744
>
> On Tue, Aug 29, 2017 at 11:22 AM, Rowland Carson <rowlandcarson@gmail.com>
> wrote:
>
>>
>> Having got my ailerons back from the painter, I weighed them. The port one
>> was
2480g before filling, profiling & painting; that whole process has added 625g
to make it now 3105g. The starboard one was 2495g, and gained 670g to make
it 3165g. The paint was 2-pack automotive which I was assured would turn out
much
lighter (and cheaper!) than the gel-coat I had originally envisaged.
>>
>> I started into the balancing procedure described in the manual. I found my
>> hinges
are not quite free enough to let the ailerons swing freely from them, so
I made loops of nylon fishing line, put them under the hinge knuckles and
suspended
the ailerons from them. Alas! - both the ailerons balance with the TE slightly
down. I find that if I put a lead weight on one horn, I can make the aileron
balance level. My piece of lead weighs 366g and level balance is obtained
with it about 50mm forward of the hinge line.
>>
>> Thus the out-of-balance moment towards the TE is 0.0183 metre-kg. I wonder if
there is any tolerance on the amount of out-of-balance that is allowed or is
safe - but I don't want to take any chances with flutter.
>>
>> Avid readers of my online build journal will recall that in May 2003, on
>> advice
---From Neville about getting the proper aileron travel, I shaved a little off
the top of the lead weights before attaching them to the aileron horns. It now
appears that either I must have shaved too much or that the painting has been
much more generous than Neville expected.
>>
>> What should I do? I suppose the ideal thing is to rub down all the paint back
to the glass/filler again and ask the painter to put on a lighter coat. I don't
have access to depleted uranium to insert into the mass horns to make them
heavier!
>>
>> I hope I might see Andy Draper at the LAA Rally and ask for his advice, but
would welcome any thoughts others on this forum might have on the matter.
>>
>> in friendship
>>
>> Rowland
>>
>> | Rowland Carson ... that's Rowland with a 'w' ...
>> | <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk [1]
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