Originally Posted by Megowcoupe

You may want more rudder than you think....

You may well be right there, Sam...however I've decided to go for the subfin only rudder, though "making the most" out of its rudder capacity, leaving the top fin as is, due to the simplicity of having a "knock-offable" stab/topfin unit as per the original....adding a skid, protecting the rudder would be neccesary though...

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Not too much visible progress lately, as I've spent some time wearing my "thinker hat"...

Here is the fuselage boom though, finally glued together, including its 2 pushrods & aerial....the boom is 10x5 mm spruce, just like the original....

More to come....

The nose centre part is a jigsawing excercise...
A fair bit of pondering is required though, when making compartments for lead, lipo, rx, servos, connectors, cable ducts etc....

During radio installation (a true shoe-horn job...!), I managed to snap a cable from the RX circuit board.......and this is SMALL...!...too small for my old eyes, i.e. I've got to get some help with the soldering....
This will delay the fuselage build, so in the meantime I'm going on with the wing....

Vintage plans are.............vintage plans.......i.e. not always crystal clear, thus leaving space for imagination & common sense...
The wing rib drawing on the plan is somewhat rough, but in a book, written before "Gladan" was kitted, the designer says "SI-63008" airfoil....
When looking at the plan, yes I can see the basic shape of said section, but it is slightly modified, possibly in order to simplify building, and/or enable "standard" stringer dimensions to be used.....and, as mentioned, the rib drawing leaves some space for "free interpretation"....

Guided by the "real" SI-63008, AND the plan, I've made a rib template that (IMHO), doesn't look too bad, so far....
I intend to use the original L/E, spar and T/E dimensions, i.e. SOME modifications have been made...hopfully in a reasonably stylish/functional way....

To be continued.....

If you haven't cut out lots of ribs already, I might be inclined to take a second look at your rib template. What I'm seeing is that the airfoil has it's maximum thickness in the first 15% or so in the template you've got, then it tapers all the way back. This gives me the heebie-jeebies, I've never seen an airfoil like that work. Typically, they don't have much lift, and they have a nasty stall. Guillows used something flat bottom with that kind of shape on their Cessna 180, and it was a woof. (never mind the up thrust.)

From what I'm seeing- the plan shows something that has less variation in thickness-plus I think the high point is a bit further back. I could be wrong, my eyes aren't great either, and it may just be a trick of lighting- but I have a hunch that designer knew a thing or two...

Sam

Dealing with vintage plans, common sense is sensible!

Sam,
You made me check it up again (and that's always a good thing to do, particularily when I am involved....)

SI-63008 has a stated max. thickness at 26% of chord, which in this case (140 mm chord) is 36.4 mm from L/E.
The max. thickness is indeed very close (or close enough) to 26%....

I understand your reaction at a first glance....the front part of this section does look somewhat "massive"...

The pics below show the result of using datum line or bottom line as a reference....

I feel relieved now, and I'm going to sleep sweetly....

A snail-like progress, I know....though, thinking about the tale of "The Tortoise and the Hare " makes me feel better....

Here's a brief report from the wing build...


To be continued....

That's beatiful work Gluehand

Lovely wing tips!!I didn't imagine plywood could be bent so easily using boiling water.

Thanks guys......here are the final pics of the finished wing, now including dihedral braces, gussets etc....
At this stage the wing weighs 38 grams, which, considering the relatively large amount of spruce, isn't too bad for a 40" wing....I was in fact surprised....

And, like always....some sanding still remains...

Just read this thread for the first time. What a fun project! I've been thinking about an A1 glider myself.

It occurs to me that, if launching free flight, on days when the air was still, you could put rubber in the line to make it pull in faster, and use a stooge set up to let go when you got a certain amount of tension. The latter might be good for me with large rc until my shoulder gets better! Using that kind of stooge, you'd be able to steer by moving the towline. And if there was enough rubber, you wouldn' t have to run at all, so your chances of falling in a woodchuck* hole and spraining your ankle would be less.

My experience with RC gliders that use rudder for turn is that you almost can't have too much rudder throw.

On windy days you might find it handy to also have a wing with less camber, so you can get some speed up to come back upwind. An airfoil like this would be very slow, which is just fine for a free flight model.

*I don't know if there are woodchucks in Sweden, but I bet you have something that acts like them:
http://3.bp.blogspot.com/_9AkJhfq-kY...d-hog-hole.jpg

Originally Posted by lincoln

On windy days you might find it handy to also have a wing with less camber, so you can get some speed up to come back upwind. An airfoil like this would be very slow, which is just fine for a free flight model.

Yep, due to the airfoil, this will definitely be a model for light winds. As I'm curious, I'll start with the unmodified original design....alternative wing(s) may be built later on...

(BTW, I'm preparing the stab build at the moment...mm, have yet to decide the size of the elevator...)


Nope, no woodchucks here, but we've got a number of other fury, digging guys around...

As expected, the stab was pretty much a "routine" job, so far....I couldn't resist making "bent" tips, in same manner as the wing tips, although these are balsa, for weight saving reasons ....
The twin elevator strips are seen on the photo....reason for the fairly wide "stiff" centre T/E, is an attempt to protect the elevators, if/when the stab (which is rubber retained) is knocked about....

Even the elevator linkage will be "knock-offable"....more on this later on....

Great looking build Gluehand - I'm surprised the hot water doesn't make the ply laminates come apart. Going to have to try that technique some time.

Thanks DeeBee1........In this particular case I brought the water to boil, switched off the stove, put the plywood sheet in the water, and just let it soak in the slowly cooling water for about 30 minutes....
Surprisingly, the plywood doesn't fall apart...it just softens....

Initially I learned this many years ago, when building the DB "Mini-Eros", where I shaped the top rear "cabin" in one piece of 1/64" ply, using this method...
Here's a scanned old B/W photo of that build...