On Fri, 12 Jul 2019 02:44:30 -0700, Senna Van den Bosch wrote:

Thanks! I will be contacting DG and SCT Terlet (where I bring my glider
for ARC) for advice. I have seen some DG-100 with different wingtips
than mine, wingtips more like the LS-4, with a very slight curve and
narrowing to the end of the tip, where my DG's wingtips have some sort
of block (about 1 inch) with a metal skid. Maybe it would be possible to
replace these?

About the tip skids: yes, it may be possible to replace them under EASA
rules - I replaced the tip skids on my Libelle without any arguments from
my inspector and Glasfaser, who hold the type certificate, certainly
didn't object. They supplied the new skids.

My original skids were certainly non-standard. They were rectangular
rubber blocks about 15mm thick, 20mm wide and 200mm long. The new ones
are bigger: 50% longer, nearly twice as wide, 50mm deep and a nice
aerodynamic shape. I haven't noticed any handling differences since
fitting them.

But, why do you want to replace yours? IMO ugliness is not a good enough
reason for a job that may be harder than it looks.

I had a good reason for replacing the old skids, which were on the glider
when I bought it. They were far too shallow because they let the aileron
touch the ground at full deflection and, as there was slight abrasion on
the aileron undersurface at the TE, I thought that fitting taller skids
was a good idea. This is why I fitted 50mm skids instead of 30mm.

That solved the aileron abrasion problem, but there are other possible
problems that you need to be aware of. These were my issues:

- the old skids served to keep the tip dollies, needed to guide the wings
into my box trailer, on the wing. These slip over the LE, wrap round the
tip and have a chord-wise extension that passes inside the tip skids and
clips over the TE to hold the dolly in place.

I was careful to position the new skids so that the tip dollies still
fitted correctly.

- my tow-out wing dolly is designed to be put on by sliding it in along
the wing after slipping it over the tip. It is a single airfoil-shaped
loop of fibreglass with carpet inside it and the wheel attached on forks
to the underside.

I completely forgot that it had to pass over the tip skids, and ended up
cutting it's top surface 50mm in front of the TE and fitting over-centre
latches to let it be opened and put round the wing from the front, rather
than passing it over the skid. That now works OK, but I had a fair amount
of fiddling to make the latches work correctly without distorting the
shape of the 'loop' and hurting the wing while still closing firmly
enough to stay in place while the glider is being towed round the
airfield. This involved two visits to the airfield for trial fitting and
adjustment with workshop time after each visit - I live an hour's drive
away from the airfield.


--
Martin | martin at
Gregorie | gregorie dot org