Twister Wing - Maiden Flight Report from the Zaerodrome

Sorry Rusty. All I got is ouch, and good luck! I will be watching....

I'll update when it starts looking like a successful repair, but don't expect one of my usual absurdly detailed build threads. I'm just chilling out tonight and figured I'd show y'all where I'm starting. Tomorrow I'll make a list of wood I need and a mental plan of how to connect it all with strong joints. Probably will wrap the joints where I can with either fiberglass or veil and stagger them. I wish I had beter carpentry skills, but when I finish, I'm sure I'll have learned something useful.

It's a possibility that I may get a whole new Twister wing kit in the mail. If that happens, then one of these will probably go in the Twister and the orher might go back into the old Osprey. I'd love to bring it baack to life one day. I'd thought it impossible at the time, 2 years ago, but now I realize it's basically the same job. Glad I kept it in the bone yard.
Rusty

Bad is when the pieces aren't able to be recognized. I have had crashes were parts weren't even 12" in length. That is far from bad.

RknRusty wrote:I'll update when it starts looking like a successful repair, but don't expect one of my usual absurdly detailed build threads. I'm just chilling out tonight and figured I'd show y'all where I'm starting. Tomorrow I'll make a list of wood I need and a mental plan of how to connect it all with strong joints. Probably will wrap the joints where I can with either fiberglass or veil and stagger them. I wish I had beter carpentry skills, but when I finish, I'm sure I'll have learned something useful.

It's a possibility that I may get a whole new Twister wing kit in the mail. If that happens, then one of these will probably go in the Twister and the orher might go back into the old Osprey. I'd love to bring it baack to life one day. I'd thought it impossible at the time, 2 years ago, but now I realize it's basically the same job. Glad I kept it in the bone yard.
Rusty

"I'll update when it starts looking like a successful repair, but don't expect one of my usual absurdly detailed build threads."

Rusty.. you get a LOT more done than me.. and still make the time to write about it! Man.. it gives a whole different perspective now that you've removed the covering. If anybody could rebuild it light and straight.. I know that you could. You're a constant inspiration to me man.

Ken Cook wrote:                     Bad is when the pieces aren't able to be recognized. I have had crashes were parts weren't even 12" in length. That is far from bad.

Ken is right. I just inventoried everything I need for the repair and it's a short list. I already have the sheets for the ribs, of which I only need four center ribs, one or two outer ribs, and 3 half ribs. My wood looks just like the same stuff. I'm heading out in a few minutes for a 1/4" square hard balsa stick for the spars and some 16th sheeting and a 1/2" LE stick.

I'll have to do some head scratching when I start butting the joints together, as I'm quite short on basic carpentry skills. But Right now it's taped to a cutout from the wing blueprint and ready to receive its new pieces. The good thing is most of the serious gluing will be almost right on the CG, so added weight won't haunt it. The new fp.40 has already proven it has more than enough power at it's last flown configuration, which was back down to 41.7 or so ounces. It's looking good. And so is the Nobler. The controls are all adjusted and locked in, it's dry-fit completely together, all it needs is glue.
Rusty

roddie wrote:

"I'll update when it starts looking like a successful repair, but don't expect one of my usual absurdly detailed build threads."

Rusty.. you get a LOT more done than me.. and still make the time to write about it! Man.. it gives a whole different perspective now that you've removed the covering. If anybody could rebuild it light and straight.. I know that you could. You're a constant inspiration to me man.

Lol, thanks, Roddie, now I have to do a good job, so as not to plunge my admirers into a funk. Okay, I'm off to the hobby shop so I can get back in time to watch my Gamecocks crush Mizzou.
Rusty

RknRusty wrote:

roddie wrote:

"I'll update when it starts looking like a successful repair, but don't expect one of my usual absurdly detailed build threads."

Rusty.. you get a LOT more done than me.. and still make the time to write about it! Man.. it gives a whole different perspective now that you've removed the covering. If anybody could rebuild it light and straight.. I know that you could. You're a constant inspiration to me man.

Lol, thanks, Roddie, now I have to do a good job, so as not to plunge my admirers into a funk. Okay, I'm off to the hobby shop so I can get back in time to watch my Gamecocks crush Mizzou.
Rusty

I wish I could ride to the HS with you. I have no idea where I'd find leading-edge stock these days. If you have trouble.. I may have some 1/2".

I think it was Ian who made a tool for accurately slotting the L/E for ribs.. if that's how yours is designed. It used a ply-plate with perpendicular raised rails representing the rib-spacing. One used an abrasive strip to cut the slot and the other located into the previously cut slot for cutting the next. I can't find the image.. but I remember how cool its' function was. OTOH.. a simple T-jig for sanding the slots to depth and width is simple to make. Just cut on the centerline and squarely.

Nah, my LE is a square stick with a sharp edge facing fore and aft. The front is carefully sanded to match a shaping guide and blend into the airfoil. The ribs have a V in their nose to fit flush against the sharp backside of the stick.

Ian and I both made a cool tool to notch the hinge slots for the control surfaces. We both got that idea from Windy.

I got all the wood I needed. The 1/4" square spar stock was not of the grain I wanted, so I got some 1/4" bass sticks too. And I got lucky, they had one hidden piece of 1/64"x8"x12" birch ply that was stuck between other wood with no bin of its own. That might be good for reinforcing my spar joints if I can't think if a more correct way.
Rusty

RknRusty wrote:Ian and I both made a cool tool to notch the hinge slots for the control surfaces. We both got that idea from Windy.

Rusty, can you elaborate on this? Maybe post pictures? Hinge slotting vexes me. I get it done, but I don't have a favorite method.

Dubro sells hand tools that are very easy to use. If you have $20 to spare a hinge slotting tool makes super quick work of the job.

Either long tapers for glue joints, or use the plywood as a "biscuit" joint, similar to how the old Sterling kits were to fit the box with the cut LE.

I have done biscuit joints with plywood, and with carbon fiber batons. Excellent results, especially since with a Dremmel the slot can be cut after the joint is initially bonded and straight.

Phil

JMynes wrote:

RknRusty wrote:Ian and I both made a cool tool to notch the hinge slots for the control surfaces. We both got that idea from Windy.

Rusty, can you elaborate on this? Maybe post pictures? Hinge slotting vexes me. I get it done, but I don't have a favorite method.

Jim there's no way to slot that won't make you cuss once in a while, but I've actually gotten pretty good at it. I bought one of the slotting kits with the handle and starter forks and cleanout gouge/hook. Ron had a better experience with his. The more I used mine, the more I hated it because the tool tips were too soft and will flex and go off course. I usually pick pretty hard balsa for the flaps, so that may be why I had more grief with it.

Now what I do before the wing and stab are installed, is first draw a centerline down the length of the both the fixed and moving edges of the flaps and elevators. For this explanation, I'm using rectangular 5/8" Dubro pin hinges as shown in the picture.

Next, after choosing and pencil marking the approximate hinge locations, I use a wide exacto blade to carefully scribe a beginning cut into the centerline at each location, a little longer than the width of the hinge. And once I get the cut going, I rock the blade while checking its angle of attack from every direction while gradually pushing it in all the way to the hilt. I do not try to open the gap wider than the blade until they've all been slit, but I do make it a little longer than the width of the hinge.

Then I take an emery board and work it into the slots to start removing some wood. When it's loose enough to get the hinge started, use the tool in the picture with the broken jigsaw blade and clean the slot out. I have the teeth backwards so they drag balsa out when you pull it. Keep cleaning it out this way until the hinge will slide in without much force.

Now for the magic Windy tool that prompted this write-up: It's for making the recess that hides the hinge and allows for a perfectly gap-free hinge-line needing no sealing tape. The tool is simply a self-limiting sanding guide. The hinges are called "5/8 inch," but the sanding bar should be made slightly wider to accommodate the pin. So make the sanding bar from 1/16" ply, which is the thickness of the hinge barrel. And make it no less than 11/16" wide. Be sure to slightly radius the edge along its sides so there are no rough edges. Now glue a strip of 220(my preference) or 330 grit paper onto it and make sure it also has no overhanging rough edges. Now glue this to a wider 1/8" plate of plywood. You can see my approximate dimensions in the picture, and I like for the plate to be a little shorter than the sanding tool so I can see where I'm starting my recess cut... read on...

Here's a picture of a hinge installed and recessed on my Twister flap, also showing the recess tool. Notice there is no gap that needs sealing:


Here's where I marked the location of a hinge to be installed on a demonstration piece:


This shows my cleanout and sizing tool made from a jigsaw blade. Also shown is a hinge laying on the recessing tool for comparison:


After the slots are all cut and sized to accept hinges, I bevel the length of the edges of the flap to a sharp 45 deg.point using the centerline as a reference. Your pencil marks should still be visible for locating the hinges. This sanding tool will cut a rectangular slot exactly as deep as the 1/16" wide hinge barrel and wide enough to accept the hinge width including the pin sticking out of each end of the barrel. Once you get started use the backing plate to gauge the depth of the cut. As you are sanding and the plate bottoms out, you'll feel the sandpaper quit removing wood. At this time, the recess is finished. Insert the hinge and make sure no more internal wood is blocking the hinge. Adjust if necessary with the saw tool, and the hinges are ready to be glued.

***IMPORTANT*** Before you mix your 30-minute epoxy, find a long carpenter's level or some flat surface that you will use for final hinge alignment. A clean door jamb will work. I use the 3/8" edge of my glass table top. Whatever you choose, make sure it will not move when you push against it. You'll understand why in the next step.

Clean the hinge tabs with acetone and apply Vaseline to the hinge barrels. Use your favorite slim tool or other method to get some epoxy into all of the slots of the flap. Apply epoxy sparingly to ONE side of the hinge tabs and insert all of them partially into the slots, cleaning as you go so you don't glue the barrels. Now press all of the partially inserted hinges at once against your straight edge until they are as far in as they will go. They should now be buried in your custom-cut slots and all will be parallel at the same depth, fully embedded in the recess. Carefully place the hinged flaps somewhere safe without bumping any of the hinges and leave the shop immediately. Go do something for your wife like loading the dishwasher or painting her toenails. I'll turn it over to you from there.

When you get back to the shop, you can finish slotting the hinge receptacles on the non-moving edge of your stab or wing TE, but DO NOT recess them. The hinge barrels should be flush with the edge of the flaps so you have a nice gap-free hinge line. So clean out the slots, test-fit and glue them up. Be sure to push the flap as tightly as reasonable against the TE and tape them to the wing so they don't back out while the glue is drying. It's tedious but professional looking. I never look forward to doing this, but the finished product is worth the trouble.

I think you were expecting a quick and easy way to slot, but all my tool is for is the recess. My second favorite way is to  bevel the edge of the moving portion and sew them together. No slotting or recessing, and it's self-gapping, but will need sealing. But it looks cool, especially on OTS planes.  Here's a combination. This was my first pin hinge job on the flaps, plus a sewn elevator. Cribbs gave me this old Sterling kit. My first flapped plane and my first Fox 35.
I think you can click and enlarge enough to see the stitches.


I hope this helps.
Rusty

pkrankow wrote:Either long tapers for glue joints, or use the plywood as a "biscuit" joint, similar to how the old Sterling kits were to fit the box with the cut LE.  

I have done biscuit joints with plywood, and with carbon fiber batons.  Excellent results, especially since with a Dremmel the slot can be cut after the joint is initially bonded and straight.

Phil

Phil, I'm considering that, at least for the LE joints. I'll have to see what looks best for the small spars.I might wrap them with .5 oz. fiberglass or carbon veil, regardless of how I join them.

I think I've got this. Carpentry tips are always welcome, but otherwise, the Sun is up and I'll post when it looks like a wing again.
Thanks,
Rusty

RknRusty wrote:Nah, my LE is a square stick with a sharp edge facing fore and aft. The front is carefully sanded to match a shaping guide and blend into the airfoil. The ribs have a V in their nose to fit flush against the sharp backside of the stick.

Ian and I both made a cool tool to notch the hinge slots for the control surfaces. We both got that idea from Windy.

I got all the wood I needed. The 1/4" square spar stock was not of the grain I wanted, so I got some 1/4" bass sticks too. And I got lucky, they had one hidden piece of 1/64"x8"x12" birch ply that was stuck between other wood with no bin of its own. That might be good for reinforcing my spar joints if I can't think if a more correct way.
Rusty

I understand now.. and I should have recalled that from your build-thread.   In the below photo; there looks to be a sanding tool on the bench. Was that used to form your leading-edge?



Ian started a thread about making a tool/jig for just that purpose. I like the application.. but I guess it depends on how much of the L/E you're replacing.. whether it's worth going through the effort. It appears that you have a similar tool there.  

https://www.coxengineforum.com/t7104-leading-edge-profile-sander?highlight=leading+edge

Nice score/good-eye on the 1/64" plywood! It cuts nicely with good sharp scissors. You'll use it on something, now that you have it.. or use-up any old stock.. knowing you have another sheet. The cost is justified.. because I find it to be very useful for laminating/shimming-up ply-plates to a desired thickness, reinforcing areas.. etc.

I'd be challenged with accurately cutting the "V"-notch in your replacement ribs. Since they're mostly the same (constant-chord) maybe pin all rib-stock blanks together in a stack.. and cut all the notches at the same time?

Here's an idea... (I know what you're thinking.. but wait for it.. LOL ) You likely have a sabre/jig-saw. Obtain a block of 3/4" square hardwood stock and cut a piece 2" long. Drill a 1/4" through the end-grain on-center, deep enough to insert an old worn blade diagonally.. and glue it in.. being mindful of the blades stroke in relation to the tools base-plate. Affix med. grit abrasive and install the blade in your tool. Pin a stack of rib-blanks together.. and tape a spacer-block to the under-base of the tool.. to prevent any gouging while feeding the rib-stack into the reciprocating block (blade). The tool can be held inverted between your knees, soft-padded in a bench-vise.. or a fixture could be built to hold it inverted. This would easily, quickly and accurately cut the 90-degree notches required. Draw your airfoil-contour afterward.. and finish off the stack by cutting (preferably) with a scroll-saw.

You know most of that already I know.. it's just a different twist on cutting the notches.

roddie wrote:I understand now.. and I should have recalled that from your build-thread.   In the below photo; there looks to be a sanding tool on the bench. Was that used to form your leading-edge?

I had hoped the aluminum sander would be useful for LE shaping, but it wasn't as helpful as I'd hoped. Maybe if it was 24 or 36" long it might have been better. It's a nice tool with 6 shapes on it. I didn't expect it to fit perfectly, but thought it would be a good starter, and I did use the widest curve to knock the sharp edge down. But the main part of the job was done with a spongy 220 block that I have had for years. I wrap and pin fresh paper on it and it's good for contouring after you get the hang of the motions, and keep count of the strokes as you go. But like Ian mentioned in his thread, I kept hooking ribs with the aluminmum one. I like to keep it in the vice so I can take a piece to it and work it. I'm still glad I bought it. If I had a do-over, I'd buy 2 of the longest ones available and saw one of them into different sized smaller ones.  

roddie wrote:Ian started a thread about making a tool/jig for just that purpose. I like the application.. but I guess it depends on how much of the L/E you're replacing.. whether it's worth going through the effort. It appears that you have a similar tool there.  

https://www.coxengineforum.com/t7104-leading-edge-profile-sander?highlight=leading+edge

I missed Ian's thread and I'm sorry, I would have contributed to it. My Twister came with a couple of those same looking ply guides, but to use them as a sanding tool, they'd have to be made oversized, and mine are not. They are for back-checking only. But if you're meticulous they help you shape the LE so it flows perfectly into the curvature of the airfoil. I was extremely proud of that wing. It was by far the best job I've ever done at building anything in my modeling experience.But it took a lot of slow work shaping. I'd take the shape tool and go down the whole wing from rib to rib, and over the center sheeting too, making minute adjustments.

roddie wrote:I'd be challenged with accurately cutting the "V"-notch in your replacement ribs. Since they're mostly the same (constant-chord) maybe pin all rib-stock blanks together in a stack.. and cut all the notches at the same time?

Here's an idea... (I know what you're thinking.. but wait for it.. LOL ) You likely have a sabre/jig-saw. Obtain a block of 3/4" square hardwood stock and cut a piece 2" long. Drill a 1/4" through the end-grain on-center, deep enough to insert an old worn blade diagonally.. and glue it in.. being mindful of the blades stroke in relation to the tools base-plate. Affix med. grit abrasive and install the blade in your tool. Pin a stack of rib-blanks together.. and tape a spacer-block to the under-base of the tool.. to prevent any gouging while feeding the rib-stack into the reciprocating block (blade). The tool can be held inverted between your knees, soft-padded in a bench-vise.. or a fixture could be built to hold it inverted. This would easily, quickly and accurately cut the 90-degree notches required. Draw your airfoil-contour afterward.. and finish off the stack by cutting (preferably) with a scroll-saw.

You know most of that already I know.. it's just a different twist on cutting the notches.

Luckily I only have to make 4 center ribs(W2), several outer ribs(W1) and a few half ribs. When I built the Osprey I had to make a lot of them with identical architecture and they fit perfectly. This might be the same wing, but I haven't checked. On that wing, I made 2 ply templates for each type rib. I soak the edges of the ply templates with CA to harden them. Then bolt them in stacks of 5 at a time plus some extras for the inevitable cracked ones. Those osprey ribs were ultra-light contest balsa, very fragile stuff. I have harder 3/32" wood for the Twister ribs and made the templates today. I'll just make a 1/8" hole at each end of the center slot to clamp the blanks together with 4-40 bolts and washers, and bore a hole to drop my scroll saw blade through and cut out the center slot up to the bolts. Take then take it to the little belt sander to shape the outsides to match the template. That's where the hardened edges of the templates helps. The V notch is close now, and I just hand finish it with my 3/4" x 3/32" aluminum sanding bar. The templates are accurate and so will be everything clamped in between. It's easy enough to finish the center slots by hand if I move the clamping bolts out of the way so I can finish the ends of the insides. It takes longer to make the templates and screw the blanks together than it does to turn it into ribs.
Rusty

Cribbs74 wrote:Dubro sells hand tools that are very easy to use. If you have $20 to spare a hinge slotting tool makes super quick work of the job.

I have every tool known to man that has been marketed for hingeing, including the Great Planes power tool thingy. Recently I have been putting a cut off wheel in the drill press and cutting nicely centered slots and using the hook tool to square up the bottoms. That has worked well, but I still think there has to be a better way. I'm going to add Rusty's jig saw blade to my arsenal and see if that helps my aggravation level.

JMynes wrote: I'm going to add Rusty's jigsaw blade to my arsenal and see if that helps my aggravation level.

You'll like it. It's sharper and really helps you square up the inside of the slot. And it's about the right thickness for a snug, but not tight hinge fit. It's a lot quicker than the Dubro hook too.

It's especially effective if you like to use hard balsa for the flaps like I do. That's why I bent up my Dubro tool.
Rusty

Hi there Rusty. I am intrigued by your hinge tool to sand the aileron, flap, elevator, etc. But What I am curious about is which surface do you sand the slot into? The fixed surface (wing, horizontal stab), or the movable ones (elevator, flaps). I will most definitely be making one of these.

Please disregard the question in my last post. Just went back and re-read and found my answer! Stupid me...

Yep, always recess only the movable side and don't forget to bevel the whole length of its edge to a sharp 45* point, last thing before gluing. Using a sanding block in a vice, and moving the flap back and forth, is the best way to get the point right on your pencil centerline. Try not to snag your new recesses or it'll make you cuss. You can leave the non-moving edge flat, or radius it a bit if you wish.

Don't forget the vaseline and a toothpick applicator, plus I always have a stack of 1/4 torn paper towels in a pan soaked in alcohol before I mix the glue. Some folks warm the vaseline so it flows into the hinge. Works fine either way for me. Keep your fingers clean, keep the vaseline off the gluing tab of the hinges, and keep the glue off of your plane's finish. And after you align the hinges and set them down, resist the temptation to touch any of it.
Rusty

fredvon4 wrote:The biggest problem with Jig saw contraptions is the up and down of those blades chatters the heck out of the wood and they are not very good for small thin material cutting

we have a similar problem with scroll saw and wrong blade sometimes but not near as dramatic as the upside down saber/jig saw

I had a spare/extra Jig saw and made the table for it from plans in a wood working magazine...  it works but is NOT my go to tool for a delicate precise cut

The Rockwell Saw in Home Depot or Lowes is simply a Jig saw upside down... I saw (pun) one demoed at Lowe's and the entire tool vibrates a lot

Incra Tools has excellent kits to make all sorts of guides, sleds, precision band saw or router tops with fences

I have one of the junk HF 4" table saws that might get a decent small table top and fence made for it one of these days

Here's my table saw contraption that Jim gave me the idea for this morning. Fred commented that it will chatter, which is right, and I'd forgotten about that, but, anyway, here's what I did. I bored a couple of holes in the saw's bottom plate and screwed the new deck on it.

What about one of these, upside down, mounted under a table of some sort?

https://www.rockwelltools.com/compact-circular-saw-rk3441k.html?mkwid=syHwgoKFi&crid=152442559919&mp_kw=rockwell%20circular%20saw&mp_mt=e&pdv=t&gclid=CjwKEAiAjIbBBRCitNvJ1o257WESJADpoUt0-KcAGP-jErbwa9eS5YZ7h91HKE4W40_Ak6B19zLiDRoCwxHw_wcB

Then you could cut a slot for a mitre gage, fence, etc.

Nice thin kerf, too.