On Monday, February 15, 2021 at 3:34:00 PM UTC-7, Martin Gregorie wrote:
On Mon, 15 Feb 2021 11:49:54 -0800, John Johnson wrote:

You can make a profile template very quickly with a piece of cardboard,
a fat marker, and a pair of scissors.

Dan 5J

Hey Dan,
Not trying to sound any dumber than I am - but is there a technique to
the cardboard and scissors approach? Or is it just a cycle of
trimming and fitting until you get it right? I don't need a very
accurate template for my case (need a sheet metal shop to make some
tie down saddles for by DG300), I'm just thinking about how to get it
right the first time.

You can also make a pair of tiedowns like I made 3-seasons or so ago for
my Libelle. These should be easily adaptable to any glider that doesn't
use winglets:

https://www.gregorie.org/gliding/tie-down/

And, for extra security, make a pair of trestles from light wood. Mine
are from 50mm x 20mm lumber, hinged at the top and padded with stapled-on
pieces of rubber-backed carpet tile. I put the trestles under each wing
at about at about 2/3 span and have used the tie-downs with 'Claw'
anchors (which are excellent and were no more expensive than the
corkscrew type). I've used this system both with a set of CloudDancer
covers and without.

The only caveat is that balsa is getting to be unobtainable now that the
Chinese seem to own all the balsa-tree plantations and are using the lot
for wind-turbine blades. However, I only made my male mould from balsa
because I have a stack of it. Moderately hard blue foam insulation,
Depron foam sheet or ever corrugated cardboard packaging should work just
as well.


--
Martin | martin at
Gregorie | gregorie dot org
Dan, thanks - will get to work on it shortly. (I was wondering if there was a mark once/cut once solution I was missing)
Martin, Your solution looks elegant but I do have winglets. Also, I prefer to have larger load distributing saddles nearer to mid-span (next to the start of the ailerons). We get some vicious micro-bursts and I worry about concentrating the hold-down load at the tips.

thx, JJ