Back to the Yak - Yak-9 Build, Part II

Kinda apples and oranges, but my leadouts are lined up with the guide holes in my Ring. The spacing is wide as well. Flies just fine for me.

Ron

Now that I got the bellcrank in place the leadouts look about right. It's got a good strong mount design with the platform glued to the bottom sheeting and the #1 and outboard #2 rib, with the pivot bolt actually going through the sheeting. I need to make a wedge to put under the platform to level it against the curved sheet, and also need to adjust the position of first couple of rib holes. I haven't glued the platform in yet.

I test fit the wing in the fuse and it's going to take some work to get it to fit the shape of the wing. The wing's LE is a lot wider than the cutout in the fuse and doublers too, and the leading edge in the fuse is cut square instead of curved like the wing. I'll have to be careful not to introduce any unwanted incidence when I start re-shaping the wing seat. Right now there's a gap between the whole top of the wing and the fuselage. This kit would be too much of a challenge for someone who's never built a model before. But it's good for me. I'll be a lot better builder after I get this one finished.

LOL,

And just think it was marketed for kids and teenagers! No wonder the views are so varied on this thing.

The kits were inexpensive compared to other manufacturers and for that reason, they were a big success. The hobby becomes more complicated as we tend to learn more and become better builders. As for being a young boy or teenager, properly fitting parts wasn't an issue. The plane was assembled regardless of how well things fit and how well it was aligned. You just went out and flew it. I remember my friend Marty had a wing that was so crooked in the fuse due to it moving and he didn't get a chance to fix it before it dried. The plane still flew. We would all laugh, but it was the comradery that we enjoyed so much of just getting together after school to go fly. For those who've seen the movie the Sandlot, we had a baseball diamond we flew at we called the dustbowl. The dustbowl for us was responsible for ruining more engines and planes. But, it's where we flew. The grass never grew and I think it was the hardest dirt on the planet.

R/C was quite expensive back in the day and as a teenager for me, it was pretty much out of reach in terms of cost. When I think back to the days where we would just run home after school and grab all of our stuff, it seemed that the most expensive part we had to purchase was the flight batttery. Many times we would share amongst all of us. I can say this, Sterling kits made me several friends and a better modeler due to their contributions to the hobby. Ken

Today was the most perfect day for flying we've had in months. Dead calm and partly cloudy. Unfortunately I had to go visit my mother in law and go grocery shopping instead. Oh well. But I did get some time to get back to the Yak. I got the bellcrank glued and bolted in place. I put some temporary leadouts on so I could check for free travel through the rib holes. I had to widen most of the holes on the front line so the wires don't touch the edges at any position of the crank. That was a pain, but some sandpaper on a 1/4" dowel and I was able to make it look pretty good.

The bellcrank has a stout platform as I mentioned in an above post, and I used epoxy just for overkill. I have some wiggle room weight-wise since I omitted the rib ripping spar. This is a strong firm wing without that spar, so I'm glad I followed that bit of advice. I had to drill long 1/8" holes through the wingtip for the leadouts to pass through. I inserted 1/8" Nyrod tube through the wingtips for the leadout guides. I sanded the tubes to give the glue some grip. Then inserted the tip into the hole and put Testors airplane glue(green tube; metal, plastic, wood) on the tube and slid it in place. I believe Nyrod is the same stuff that is the yellow extensions on the Killer Bee needle. I left the tube flush with the wingtip, so only a pinhole in the Monokote is needed for the leadout to pass through. It should look neat and clean. I hope that Testors glue will hold them, but they press fit pretty tight anyway.

I guess the next step is to mount the flaps. I originally thought of stitching them, but I've decided not to in case I feel the need to seal the hinge line gap with tape. I haven't decided what kind of hinge to use, but I'll probably go with some sort of fabric. I'm going to search out hinges and look at different types first. I'll be glad to finally get this wing out of the way. Next I'll have to figure out how to make the wing fit the fuse. As I mentioned, the cutout doesn't match the LE as it's square. I might block it up with balsa and re-cut it' I wish I had kept a piece of the leftover LE stock for the shape. The doublers have an LE shape, just not the shape of my LE. I might try to re-shape them with sandpaper and use that to draw the curve. Since the fuse is slightly bowed, a new slab isn't out of the question either. But I'll jump off that bridge when I get to it.

If you use a fabric hinge then using a film covering is going to be difficult.

You can also use nylon, which is available in pretty thin rip-stop versions. I'm not sure what they give in the kits.

Phil

I would go with a monocote hinge.

Jim

I am an advocate for the nylon pin hinge. Mostly for the way it looks, but it does allow very smooth controls.

I'll see what they have when I visit the HS tomorrow. As for fabric, i was laying in bed last night wondering how I would use them along with Monokote covering. So, yeah, that occurred to me. I'd like to try pin hinges. I suppose you make the slots, then cover it and punch through the Monokote into the holes to glue them. I could improvise a slot tool.

As for Monokote hinges, once I tried ironing two strips together with the adhesive on opposite sides, planning to then iron them on in over/under fashion, but I could pull them apart, so I ditched that plan. Maybe I didn't do it right. But it sounds too lightweight for .35 stunter flaps. I could be wrong.

RknRusty wrote:I'd like to try pin hinges. I suppose you make the slots, then cover it and punch through the Monokote into the holes to glue them. I could improvise a slot tool.

Yep you simply make your marks and drill the holes and once covered, you cut away the covering and glue your hinges in.
I found that the best glue to use is either Tite Bond or Gorilla wood glue as they are water based and easy to clean up. However, I recommend roughing up the hinges with some sandpaper and then cleaning them with rubbing alcohol before gluing.

I used pin hinges in my foam core wing.

RknRusty wrote:As for Monokote hinges, once I tried ironing two strips together with the adhesive on opposite sides, planning to then iron them on in over/under fashion, but I could pull them apart, so I ditched that plan. Maybe I didn't do it right. But it sounds too lightweight for .35 stunter flaps. I could be wrong.

Another way to use Monokote as a hinge is to use it like you would use a tape hinge on a foamy. It works great, strong and clean. I've used Monokote hinges on planes as big as a .35 size c/l stunter with no problems.

Here is a pic of my Gee Bee with a Monokote hinged elevator. I used one piece of covering for the top and one piece for the bottom on both the stab and elevator.




Shawn

Thanks, Shawn.

RknRusty wrote:I think Wayne is ready to go most any time I want to. His only problem is the 90 mile round trip he has to do to come to my field. Or even more for me to go to his. He lives an hour from my house. But he told me he can go most Tuesdays or Thursdays, and sometimes on Sunday. So barring other business I have to schedule on those days, we should get some time in. I have tree people coming this Thursday, and company coming this weekend, but I should have some time to work on the Yak.

I'm at the point that I need to figure out how to proceed. I'm going to get pin hinges, and I have my white Monokote. So I guess I should cover the main wing so I can de-warp it before I cut hinge slots. The TE is bowed, but the flap pieces are pretty straight. I think I can cut slots just the same through the covering. What are your thoughts on that? I may just paint the flaps white instead of Monokoting them. That'll make them more ding and dent resistant.

If you want to, you can copy the Yak quote and answer it in the Yak thread.
https://www.coxengineforum.com/t5232-yak-9-build-part-two

Yeah it's just as easy to slot hinges with the covering on. Use something that wipes off easily to mark where you are going to slot on the wing and flap. Also make the slots slightly oversize so you have some wiggle room to line things up.

One more thing, use vaseline or grease on the pins to keep the Epoxy from flowing into the pin area.

Ron

Did you find it necessary to use a slotting tool, or just a fresh exacto blade?

Depends, on 1/2A I just use a knife. For the larger ones I use a very cheap manual slotting tool that I bought over 20yrs ago.

Hinge slotting tools like the Great Planes Slot Machine are excellent for larger projects or if you do a lot of building.
For smaller budgeted builds, a fresh #11 exacto will work just fine. No matter which method you use, I highly recommend a hinge marking tool such as this, http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK262&P=7 They make the chore much easier.

Shawn

sdjjadk wrote:Hinge slotting tools like the Great Planes Slot Machine are excellent for larger projects or if you do a lot of building.
For smaller budgeted builds, a fresh #11 exacto will work just fine. No matter which method you use, I highly recommend a hinge marking tool such as this, http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK262&P=7 They make the chore much easier.

Shawn

Thanks Shawn, I was wondering how I was going to find a true centerline. I'm famous for botching measurements. I definitely want to see it all press-fit together and working before I cover it

RknRusty wrote:

sdjjadk wrote:Hinge slotting tools like the Great Planes Slot Machine are excellent for larger projects or if you do a lot of building.
For smaller budgeted builds, a fresh #11 exacto will work just fine. No matter which method you use, I highly recommend a hinge marking tool such as this, http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK262&P=7 They make the chore much easier.

Shawn

Thanks Shawn, I was wondering how I was going to find a true centerline. I'm famous for botching measurements. I definitely want to see it all press-fit together and working before I cover it

Hinging was the one thing I always dreaded. Especially when using the old DuBro slotting kit with the fork blade and the balsa pick and trying to keep the fork blade centered without punching through the sides of the surface. I couldn't tell you how many times I messed up a perfectly good build in the past when trying to make hinge slots.
That centering tool however, makes a big difference!

Shawn

sdjjadk wrote:Hinging was the one thing I always dreaded. Especially when using the old DuBro slotting kit with the fork blade and the balsa pick and trying to keep the fork blade centered without punching through the sides of the surface. I couldn't tell you how many times I messed up a perfectly good build in the past when trying to make hinge slots.
That centering tool however, makes a big difference!

Shawn

I'm not looking forward to it either. Boring 1/8" leadout holes through the 1/4" or so wingtip blocks was a little hairy too, but I managed to do a neat job of it.

RknRusty wrote:

sdjjadk wrote:Hinging was the one thing I always dreaded. Especially when using the old DuBro slotting kit with the fork blade and the balsa pick and trying to keep the fork blade centered without punching through the sides of the surface. I couldn't tell you how many times I messed up a perfectly good build in the past when trying to make hinge slots.
That centering tool however, makes a big difference!

Shawn

I'm not looking forward to it either. Boring 1/8" leadout holes through the 1/4" or so wingtip blocks was a little hairy too, but I managed to do a neat job of it.

My Uncle got me into this hobby when I was a kid and he taught me some neat building tricks along the way and one of those tricks he showed me when drilling lead out holes like you mentioned (and hopefully this will make sense) was to jig the wing tip in place and then chock a length of brass tubing to the lead out marks and then use the tubing as a drill guide.

Shawn

I only have 1/8" thick TE and flap edges. That's not too small to slot for hinges, is it?

No, should work, that's what most are.

Ron

I went to the LHS this morning and had an experience I've only heard about from other guys on the forums. I had a shopping list that included nylon hinges, 2-56 and 4-40 clevis kits, solder coupling links, a slotting kit, and a #3 exacto handle. I picked up some threaded rod too, just in case.

I also traded a couple of woody 9" props for a 10x3 and a 10x4. I have a new plan(Don't I always! ).
I'm going to start running the Shoestring engine like it's meant to be run. Trying to get a dependable 4-2 break is too undependable and requires fiddling with the needle on every flight. It works when it works but wastes time and fuel when it doesn't. If I'm going to fly in a contest, I need to know what it's going to do on every run. So I'm going to try a bigger prop that will get the lap times I want and be ready for the vertical climbs and demands of stunts without me gritting and hoping it breaks lean at the right time. It just ain't a Fox, and isn't meant to be, as much as I tried to make it act like one. Some of you told me so.

So, I'm browsing the shop and I hear a voice from the other side of the aisle say, "Hey, I've seen you fly before!" I looked up and there was a tall red headed guy grinning at me saying how cool that exhibition at the Jackson Fliers club I put on was. I had no idea when he was referring to, and I said, "You mean the 1.2A planes?" Yeah, the little ones, they really scoot. Then another dude says, "You fly control line, me too, I thought I was the only one left." And the conversation exploded into everything we could spill. We had a great time comparing notes, and he's a big Flite Streak fan, big and small. He said he has about 60 engines and if I ever build a kit to let him know what I need. He lives at Surfside Beach, near where I go every Summer, and am going again in September. We traded info, and after a half hour of laughing and talking we parted ways. I thought, damn, this is what those guys mean when they talk about visiting hobby shops and meeting up with other like minded people. That was more fun than picking out lingerie with my wife at the mall and sneaking into the dressing room to see how it fits... well, almost. It was super cool to go to a hobby shop and actually talk to someone who understands what it is I do with all this hardware I buy.

So I got home and practiced cutting slots and hinging, e-mailed my new friend so he knows how to contact me. Went out to check the mail and found my Shoestring fuel in a box on the porch. Yesss, great day. Looks like Tuesday is going to be a flying day. I had expected to be out of gas for a few more days. And, the progress on the Yak is about to accelerate. We went to the baseball park to take in a game and a few beers tonight, and tomorrow I will get some building done. And I promise Tuesday, I will turn the camera on and show y'all my new pattern skills.

Okay, this is just a rambling account of my day, but it's all good. Stand by for what happens next. See y'all later.
Rusty

Haven't had that experience...yet. I am told I am "the other" control line guy in town, although the LHS is an hour drive from me.

I am sure it feels wonderful. (I have had similar experiences in other hobbies)

Phil