SIG Banshee Wings

Also I would like to use both a Silver Fox 40 and a K&B 40. Anything I need to consider there?

Thanks

The Silver Fox 40 and the K&B 40 are both good engines.

I assume you are trying to build the wing on a level flat surface. Something like a work bench, old door on a couple of sawhorses, etc. If not, stop gluing until you've got a true surface on which to build.

Cover the flat surface with something that will accept pins, I use a product called (I think) cortex from any building supply. It's white on one side and tan, unfinished on the other and about 1/2" thick.

I'd suggest you build the wing initially upside down. this will allow you to build the complete trailing edge, install both spars and leading edge and sheet the (bottom) center section with the wing pinned in place and thus straight and square. I'll refer to top and bottom from now on assuming you are, in fact, building the wing upside down. The words (top) and (bottom) will be inclosed in parentheses to remind you.

It is good practice to pre-assemble the spars, leading edge and trailing edge sheeting prior to assembly. Join each with a 45 degree splice joint and plan to install a doubler over each joint after the wing is assembled and before sheeting over the joints.

Once you've got the flat surface in place, pin the (top) trailing edge sheet directly to the table top (I like to make a copy of the plan and attach it to the surface and build directly on the plan).

Lay a rib in place and note how far off the table top the spar cutout is. Now cut a tip to tip strip of balsa to this thickness and pin the (top) spar to it while you position all the ribs held in place with pins. Use a square cut chunk of scrap to insure the ribs are vertical and hot-stuff the ribs to the (top) spar and (top) trailing edge sheeting.

Install the (bottom) spar, recheck the ribs square and vertical, and hot-stuff in place.

Now glue the (bottom) trailing edge sheeting in place using either slow drying CA or (my choice) an alphatic resin glue like Tite-Bond.

Install the leading edge. this can be tough to do right. Try to pin it in place at each rib to insure that it is well seated. Once you're certain it is properly located, hot-stuff it in place.

Glue the bottom center-section sheeting in place while the wing is still in place. It's nice technique to have a "flared" curve to the sheeting where it joins the leading and trailing edges. this not only looks good but spreads the stress riser formed by the sheeting over a broader span making the joint stronger.

I also like to install the basic wing-tips while the wing is jigged in place. It makes it very easy to make them square. Simply cut some scrap balsa (or foam blocks if you have some foam laying around) the right thickness to slide under the tips and exactly center them in place on the tip rib. Glue the tip in place thus perfectly straight and add the (bottom) little riblets and sparlets that hold it square. This is also a good time to install the adjustable leadout guide if you are planning on using one (hint, you should!)

Now the reasonably square and about one-half-finished wing can be unpinned and turned over. YOu should be able to repin it in place, now right-side-up. This will allow you to install the controls, sheet the (top) center section and install the (top) riblets and sparlets on the tips.

At this point the wing should be rigid enough to take of the board for final assembly.

Good luck.

I assume you are trying to build the wing on a level flat surface. Something like a work bench, old door on a couple of sawhorses, etc. If not, stop gluing until you've got a true surface on which to build.

Cover the flat surface with something that will accept pins, I use a product called (I think) cortex from any building supply. It's white on one side and tan, unfinished on the other and about 1/2" thick.

I'd suggest you build the wing initially upside down. this will allow you to build the complete trailing edge, install both spars and leading edge and sheet the (bottom) center section with the wing pinned in place and thus straight and square. I'll refer to top and bottom from now on assuming you are, in fact, building the wing upside down. The words (top) and (bottom) will be inclosed in parentheses to remind you.

It is good practice to pre-assemble the spars, leading edge and trailing edge sheeting prior to assembly. Join each with a 45 degree splice joint and plan to install a doubler over each joint after the wing is assembled and before sheeting over the joints.

Once you've got the flat surface in place, pin the (top) trailing edge sheet directly to the table top (I like to make a copy of the plan and attach it to the surface and build directly on the plan).

Lay a rib in place and note how far off the table top the spar cutout is. Now cut a tip to tip strip of balsa to this thickness and pin in place on the building surface. This strip and the trailing edge sheet pinned to the table top are now your building jig for the wing.

Pin the (top) spar to the support strip and position all the ribs held in place on both the trailing edge and the (top) spar with pins. Use a square cut chunk of scrap to insure the ribs are vertical and hot-stuff the ribs to the (top) spar and (top) trailing edge sheeting.

Install the (bottom) spar, recheck the ribs square and vertical, and hot-stuff in place.

Now glue the (bottom) trailing edge sheeting in place using either slow drying CA or (my choice) an alphatic resin glue like Tite-Bond.

Install the leading edge. this can be tough to do right. Try to pin it in place at each rib to insure that it is well seated. Once you're certain it is properly located, hot-stuff it in place.

Glue the (bottom) center-section sheeting in place while the wing is still jigged to the table. It's nice technique to have a "flared outward" curve to the sheeting where it joins the leading and trailing edges. This not only looks good but spreads the stress riser formed by the sheeting over a broader span making the joint stronger.

I also like to install the basic wing-tips while the wing is jigged in place. It makes it very easy to make them square. Simply cut some scrap balsa the right thickness to slide under the tips at two loctions...one forward near the leading edge and one aft, just forward of the trailing edge sheeting...which exactly center the tip itself in place on the tip rib. Glue the tip in place thus perfectly straight and add the (bottom) little riblets and sparlets that hold it square. This is also a good time to install the adjustable leadout guide if you are planning on using one (hint, you should!)

Now the reasonably square and about one-half-finished wing can be unpinned and turned over. YOu should be able to repin it in place, now right-side-up. This will allow you to install the controls, sheet the (top) center section and install the (top) riblets and sparlets on the tips.

At this point the wing should be rigid enough to take of the board for final assembly.

Good luck.

>Any tricks to help build these straight?
>
Ted has really covered a good way to keep that one straight (and I will print a copy to keep for myself). I am almost too embarrassed by the high-falutin' company to add my little bit of warning..

>Also I would like to use both a Silver Fox 40
>and a K&B 40. Anything I need to consider there?
>
The Banshee itself was designed around the earliest of the Fox 35 engines, at 6 ounces, there are 19's that are heavier. But that exceedingly long nose is even too long for one of those if you use a muffler with it (or not, depending on several things). The Torp 40's are in the "Ten Ounce Plus" range (it's more for late K&B models and ABC's than older 40's). The Fox 40 isn't quite so bulky, but still is close to three ounces heavier than a Fox 35, prior to thinking about mufflers.

The Torps are usable stock, but don't run the old style 4-2-4 unless they are reworked. The ABC Torps sold by John Brodak would perform that way. Whether with the Fox or Torp, start with 11-5's and experiment with props from there. For either one, cut the Banshee nose to Twister length, or better yet, glue the hole in the fuselage where the wing is supposed to go back in place and cut a new hole an inch and a half forward of the kit's own location.

Kiwi

You've been given great info so far, so I won't re-do that. I like the Banshee, a lot, and have used it with the Brodak ABC 40 with a chip muffler, and muffler pressure. They work very well, with the adjustments mentioned earlier to the nose length. The Top Flight Power Tip 11x5 is the cat's meow on 57ft lines, I did 5.4 laps on Sig 5% nitro.

A change I made to the design, was to build the wing with a sheeted leading edge and cap stripped the ribs. It opens up the airfoil with the extra balsa, and lets you sand it a bit more blunt, and gets rid of any flex.

The one thing I would add to what has already been said, as to building straight now that I think about it, is that as of late I have started using a combo of Tom Morris "building with weights" but still using fast C/A to tack things while the alaphatic dries. The weights hold things straight after you walk away. I always leave the weights on in between building sessions, right up until I put the wing in the fuse. Humidity can do funny things here in the South! Once the wing is in, I don't like to take too long before I'm ready to cover it either.

Mine had a Sig 3" belcrank, which is OK, just use the slowest position, though I'd be tempted to use a 4" if I built another some day. Try to put as much effort into the control system as you do the rest of the plane! It will pay off big!

If you scratch build with decent weight balsa where it counts, it is a great airplane to practice the full AMA pattern on, and compete with too.

Have Fun
Eric

Or, I can delete (If I see a double post, I usually do). But if you have edited one of them, I would rather that you removed the one you didn't want.

You can, also, (if you have got the time) use the "Preview" button to see who the message is going to look before posting it. That way you can catch a lot of errors (or change something that didn't quite come out right) before posting.