I/2 A Pathfinder questions...

[jim gilmore]

This is a general question toward anybody whom is familiar with both cad and laser cutting.
I'm curious how hard it would be to get the wing spar for the 1/2 A pathfinder laid out and cut and if cutting a bunch at a time would reduce the cost ? how much and how many
suppose it was laid out as being (1) solid piece and were cutting 4 or five at a time ?
anybody have a clue ?
I,ve been cutting the inboard spar for the last (3 ) hours and have another hour or so to go. I still need to notch the 1/32 spar and cut the second spar out....
This while listening to my MOM complain about how bad it is here. The bugs are awful, the cats under the bed are scaring her and my kids won't talk to her. She is going to go home and she doesn't want to complain but we cook with too much oil thats why the house smells.


Uhm,  remember I'm visiting her, and here taking care of her. There are NO cats or bugs. And what ever smells I have no clue. But when I talk I talk too loud..... sigh   I'm going to need a lot more drugs and therapy.

[John Miller]

Jim, I might be able to help. The 1/2A Pathfinder was drawn in CAD. Brodak has the files, and should be able to cut the spars without too much of a problem. I'd suggest giving him a call and ask him what it would take to get the spars laser cut.

[Ralph Wenzel (d)]

Sounds like you're doing it the hard way, Jim, with an EXACTO knife. Cut off two short (6") sections of a hacksaw blade and tape one end together. It will now make perfect 1/16" cuts. (And it wont split the spar, either)  - It cut's easier if you tape it so the you cut on the "Pull" stroke.

[john e. holliday]

Jim, I am glad you have something to work on.  Now as far as Mom, I know you are taking care of her.  No matter how bad it gets, she is the only one you will ever have.  My Mother passed in 91 in a nursing home on Thanksgiving morning.  She had to have 24 hour coverage/attention.  I had just visited her the weekend before and she was as sharp as a tack.  My oldest daughter wanted us to bring her home so she could take care of her.  She didn't realize that she required oxygen most of the time besides the drugs the doc was giving her.  So take care young man as we in the modeling world are here to help.  DOC Holliday

[jim gilmore]

Darn I was going to try dropping her off when they were doingb trade in's on clunkers.
Ok, Its a bad joke but hey I am grateful for all the moral support I have gotten here.
Now for a simple question of model building ethics for you all.
When cutting out the spars the b/p shows nice rounded corners on the inside cutouts. I am wondering how many of you actually take the time to make all the internal holes as neat as can be ?

[Roger Vizioli]

Jim,
Yes on rounded corners for the cutouts(for bellcrank and leadouts).
Right angle corners are prone to cracking.
Sandpaper on a dowel or round object will make it easy.
R....

[Robert McHam]

"Sandpaper on a dowel or round object will make it easy."

How true but I can't think of an easy way to put sandpaper on small dowels!
BTW, How small are we talking about here? I am imagining 1/8" and smaller dia. dowels.

Robert

[Roger Vizioli]

"Sandpaper on a dowel or round object will make it easy."

How true but I can't think of an easy way to put sandpaper on small dowels!
BTW, How small are we talking about here? I am imagining 1/8" and smaller dia. dowels.

Robert

I've used contact cement or ambroid with success, down to a 1/8" dowel. P'finder cutouts he mentioned are are 1/8", 3/16" and 3/8" wide.
Probably could use other adhesives. I wrap the setup with a layer or two of note paper and tightly wrap that with masking taped until the adhesive dries. Make sure no adhesive seeps through the seam to the sanding surface.
Roger

[jim gilmore]

Ok, I found some 180 grit sand paper and cut it into 3/16 strips and glued it on a skewer with typical glue stick and  rounded the areas out. Now my spar is fully done as best as I can get it. Not fantastic looking but it will work.

[Roger_Pion]

 Pick some sand for the coarseness or fineness you want.  Generally, I use the stuff one buys for the bottom of pet reptile aquariums, but that's 'cause my kid has a pet reptile so there's a handy supply.  One can also throw some sand through a sieve.  Whatever, just find the sand you want and get it pretty clean.  Spray some 3M contact cement onto the dowel and then roll it in the sand. Wait 10 minutes.  Presto!

[jim gilmore]

OK, next question on the pathfinder. The sheeting and leading edge are both cut in half but I was wondering where everybody else splices it. I didn't see any instructions on doing so and would think a butt joint is the weakest joint.
I will continue to use this thread to ask questions on this plane.

[Geoff Goodworth]

Jim

The finished lengths of these parts are all less than 36" so you could replace the the short lengths with continuous strip. Since the centre ribs are spaced 3/8" apart, I would use some light 3/8" sheet as spacers between the ribs at the LE and the TE. Butt jointed TE sheeting and LE glued to the spacers should be strong enough.

Good luck

Geoff

[jim gilmore]

Next question on the 1/2A pathfinder.
Does it have to have the flaps work or could it just be elevator control only ? I've made no decision one way or the other yet.