Hi every1, I have orderd a sig riser kit and seen as thought its a glider the weight issue is even more crucial than for example the average trainer, so I would like to know some techniques everyone is using to keep the weight down when building a kit... I'll appreciate any help

Regards

Darren

Cut lightening holes in all formers and sheeting wherever possible especially aft of the CG. Also use as little glue as possible. Some coverings are lighter than other so that is also a place to save weight.
Good Luck!!
Anthony

I haven't flown my 2 meter gliders for some time now but
when I was building them I always was concerned about
the weight . Usually I was trying to add it to attain a good
flying weight . I'd suggest that you make provisions on the
CG so you can easily add or subtract weight, (ballast) to
suit the conditions.

I have a Riser and I remember that it was not uncommon
for me to add ,(more often than not)several oz of ballast .


Regards
Roby

Sand all the sheets before you pop them from their die-cuts and cut uniform lightening holes in ribs and formers if they don't already have them.

I wouldn't cut lightening holes into balsa ribs. those few gramms of balsa are not worth the loss of strength that the holes would cause. Take this rib for example, that lightening hole is pure nonsense. When I was sheeting the wing two ribs broke because there's so little wood between the cutout for the spars and that hole.

Cutting lightening holes won't do much.
For the structure the key to lightness is to be careful about getting tight glue joints that need little glue.
For the complete aircraft, chosing the correct covering can also save weight. This is especially so for a glider that has a light structure with lots of wing area.
Using miniature servos and pull-pull linkages will save some weight as well.

Here is a list of covering weights to help you choose:

[link=http://pldaniels.com/flying/balsa/rc-model-aircraft-covering-materials.html]http://pldaniels.com/flying/balsa/rc-model-aircraft-covering-materials.html[/link]

IMHO you don't need to be overly concerned about weight. The minimum sinking speed will suffer if weight increases, but the glide ratio will remain approximately the same. This means that a heavier glider will need a stronger thermal to stay up, but on the other hand it will be able to cover the distance between thermals with less altitude loss if there is a head wind to fight against.

/Red B.