CL-415 winter project.

[Papa]

In your dreams. I like Robert Pike's "Arctic Andy"

Jack.

[Michael]

Igloo Andrew

[Andy Hoffer]

You can't begin to know how very flattered I am that so many of you have invested the time and effort to demonstrate your considerable alliterative lingusitic talent in my honour.  I do hope to have the pleasure of your company at Rogo field this winter (Sunday's forecast is perfect!) so that I can show my deepest appreciation in person.   

Sincerely,

Andy "Ice Man" Hoffer

a.k.a "Arctic Andy", "Igloo Andrew"  (Mita really liked that one!),  "Abominable Andy" and "Frostbite Freddy"  !

[wollins]

Ok for all you BBs (balsa builders  ) out there ... what's the best method of gluing sheeting to an open frame?  I've only ever sheeted foam cores.  I've read that one method is to attach the sheeting to the main spars with wood glue, then once dry, use CA to attach the sheeting to the ribs. Additionally ... use wood glue for the leading edge where there will obviously be significant sanding and shaping going on.

But what/how do you guys recommend it to be done?

Colin

[Papa]

I used medium CA on the Northstar but it is tricky and you have to get it right the first time.

With a conventional wing I like to glue the sheet to the leading edge only to begin. I use wood glue. My glue of choice is a new LePage's Express wood glue. It drys in 10 minutes, is hard, clear and sands well. You can use weights, clamps or pins to hold it in place. My preference is for weights.

I like to leave it for a couple of hours or over night. I use a disposable brush, I buy them in packets of 20 in Princess Auto, to brush wood glue on the remaining areas and press the sheeting in place and then weigh it down until well dried. The label says 10 minutes but I like to leave it for a couple of hours. If the curve is excessive you can put a damp cloth on the sheeting, where it has to bend, for about 5 minutes before gluing to help it bend. Use a damp cloth not a wet one.

If possible cut the sheeting oversize and trim or sand to size after the glue has dried. I use a miniature block plane I bought in Lee Valley. It is set to a fine shave but it is amazing how fast it removes waste and saves an awful lot of sanding. http://www.leevalley.com/en/Wood/page.aspx?p=50232&cat=1,41182
The chisel plane is great for shaving wing seats etc.

Good luck.

Jack.

[piker]

I use medium CA for sheeting, although it creates an urgent situation (ya gotta keep moving  )

For LE sheeting, I'll start at either the LE or spar and glue to that and the first inch or so of each rib,  after that is cured, I carefully peal back the sheeting and run CA down the rest of the rib edges and lay the sheet down.  Finally I glue along the last edge (either LE or spar) to finish off.  The same applies to full sheeted wings or, say, fuselage sheeting.  I glue an area of structure, with CA, that I figure I can handle within a reasonable period of time (say 30 seconds) then after the sheeting is started, I peel back and continue as usual.  Another option for your fuselage sheeting would be to attach the perimeter, then from the inside, wick in thin CA to the remaining frame pieces.

[wollins]

Another option for your fuselage sheeting would be to attach the perimeter, then from the inside, wick in thin CA to the remaining frame pieces.

Aha!  That's exactly what I was thinking!

[wollins]

I use wood glue. My glue of choice is a new LePage's Express wood glue. It drys in 10 minutes, is hard, clear and sands well. You can use weights, clamps or pins to hold it in place. My preference is for weights.

Awesome info Jack, thanks!  Is the LePage Express a polyurethane glue? (does it foam/expand up when drying)

Colin

[Papa]

No it's a straight aliphatic white wood glue. It's almost as fast as some epoxies. Frank van Beurden has become a believer and is on his second bottle of the stuff.

You can use it on the fuselage sheeting but I hold it down with strips of rubber cut from old inner tubes from pedal bikes. They give you about 4 long strips about 3/4" wide which exert a considerable amount of pressure with just a small amount of tension.

Jack.

[wollins]

Ok got a little more done.  She's got her keel now and a wing saddle.

Colin

[Papa]

Starting to look like a plane. Looks really nice Colin.

Jack.

[michaely]

On gluing leading edge sheeting onto to an open framework.... similar to Jack, I typically use rubber bands at each rib fastened with pins at the front and rear and except for very robust frameworks, I do this with the framework pinned down to a building board so not to introduce a warp... not a lot pressure is needed... I use wood glue on ribs and like the open time wood glue provides to get all the clamping action in place.

Michael

[wollins]

Thanks Michael. 

Incidentally I popped what I've done so far on the scale and I'm blown away by how little it weighs. Obviously my astonishment is due to the fact that i'm not accustomed to this sort of build but hey it was a nice surprise.  To put things in perspective, the Esc alone in my Hawker Typhoon weighs almost as much! lol!

Colin   

[piker]

Hey Colin,

That structure is looking great!  Good job.  Keep going.

BTW, I sent you a long text in answer to your plywood question, but it's not sending for some reason and I don't want to type all that on my phone again... so I thought I'd put the info here for you, and anyone else who may not be aware of the differences between Light Ply and Aircraft Ply.  Of course we're open to input with additional information and/or corrections   

Light ply is that stuff that a lot of ARFs are made from and the stuff they make tangerine boxes out of... See below    It has it's uses, but I never use it while building planes (unless it's part of a kit) because I prefer other, higher quality options.  I've only ever seen it in 1/8" thickness and it's that crappy plywood made up of only three ply's.  It's not very strong, but it's cheap and fairly light.  It's useful for making bulkheads/formers from, instead of balsa, as the problems associated with grain have been reduced (that's the point of plywood).  I say only reduced because it does still have a grain with the two primary, outer layers oriented in one direction with only the crappy middle layer at 90 degrees.  So it will still crack along it's grain with little effort.  I personally prefer to use either a home made balsa ply, with two layers of balsa at 90 degrees to each other, or a balsa core with very thin (1/64" or 1/32") aircraft ply on the outsides.  That way you get a strong, but fairly light former that also looks nice.   

Aircraft ply is the heavier, multiple layer, plywood that is made from much better wood, and it comes in many thicknesses.  You can tell the difference between it and the 1/8" light ply by counting the number of layers.  1/8" aircraft ply has 5 layers, Light ply only three.  Aircraft ply comes in various sizes, with the most useful sizes for us being 1/64", 1/32", 1/16" 1/8", and 1/4".  There may be other sizes in between, but I've never used them.  I never use the 1/4" ply.  If I need extra thickness, say for a firewall on a large model, or wing bolt anchors, or landing gear mounting plates, I simply double up the 1/8" that I always have on hand.  I use 1/8" for structural members like mounting plates, keels on flying boats, firewalls or supporting structures, etc.  It's quite heavy so only use it where you really need it.  I use 1/16 for doublers, to harden surfaces like the bottom of a flying boat hull (for belly landing on ground), and sometimes for doubling up balsa ribs for servo mounting or surface separation points (where balsa alone would get it's edges beat-up from use), like wing saddles, ribs where wing panels separate, etc.  Again, use it cautiously as the weight can build up.  I use 1/32 and 1/64 for former laminating and for general surface hardening.

Generally I use plywood as little as possible, but sometimes it's necessary in highly loaded areas or areas where every day use will damage the model.

In the case of the bottom sheeting on your hull, the 1/16" aircraft ply will give you that hard surface you're looking for, for belly landings on grass, and it'll form to the curvatures of the hull better than the 1/8" light ply.  You MAY even get away with 1/32" ply, but I know I used 1/16" ply on my CL-215 because I was tired of repairing the 1/8" balsa bottom after landing on rough ground.

I hope that answers your question.  Let me know if it didn't.

[wollins]

I hope that answers your question. 

And then some ... wow! Thanks!  I'm really enjoying this cause its actually educational. Ok back to the build cause I have an inspector coming by tomorrow at 10 to critique my progress! lol!

Colin