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

Thanks, I'll just be happy when all I have to think about on this plane is anything in the tank.

Maybe I'll invite the Amanda Fish Band to come play their Fox Fuel can guitars for the Yak-9 Maiden Day celebration. 

Rusty, many of the older Fox's just don't like to be muffled. This is usually the ones with no web castings within the exhaust area. I've done it, however they're generally not happy about it. They perform better with a tongue muffler that's free flowing. Many of the older Fox mufflers (70's) were superior to the current muffler. The muffler available now is pretty much useless. I shouldn't say useless, it does work well for breaking the case on a crash and also acting like a can opener for your fuel tank. I would try it and go from there. We can't fly without mufflers and we tend to adapt. Ken

Based on wha Ken said then a tongue would be the way to go. Since your '54 Fox does not have muffler lugs you could make a tongue that has mounting holes on it and run j bolts through them and attach those to a strap going around the back of the case. Would be simple and cheap to do.

Ron

If you do as Ken and Ron suggest...any muffler or tongue muffler (better bet weight wise) be sure on your older Fox to have some sort of strength fill in materiel around the outside inner port of the engine. A simple band strap with enough torque to hold the muffler will cause a bind in the case and liner and give your grief...I have seen folks with older Fix 35s use leather or hard rubber inside the muffler strap to dissipate the load successfully

In fact here on CEF I believe Ken has a photo of the idea I am explaining

None of this is press fit. She's screwed and glued. The stab lines up perfectly on the first try. She's hanging from a 1/8" wire tail skid that ends with a stooge loop.




Click for a larger size pic:


Yeah! I'll do the filets Sunday. Got an MCLS meeting/lunch/fly-in at Watt's field tomorrow.
Rusty

Looks superb!

I can almost hear the Fox break now.

I am flying tomorrow as well at our local field. Our club doesn't have a fancy name like yours nor is the field named. It basically consists of several Okie good 'ol boys and our captive audience is a bunch of cows.

I am excited as I will finally get to fly the full fuse Twister and the Cardinal.

Ron

Cribbs74 wrote:Looks superb!

I can almost hear the Fox break now.

I am flying tomorrow as well at our local field. Our club doesn't have a fancy name like yours nor is the field named. It basically consists of several Okie good 'ol boys and our captive audience is a bunch of cows.

I am excited as I will finally get to fly the full fuse Twister and the Cardinal.

Ron

I hope you have a great time. I wrote you a good story about flying in the wind yesterday and must have not clicked send. I'll re do it tomorrow. Are you still practicing OTS or are you doing any PAMPA patterns.

I think she looks good too. Filets and paint and a couple of minor details and she'll be airworthy. I might blow off the special markings and exhaust pipes and just fly it. No reason I can't do the extras later.
My mind is increasingly occupied with the Reed Speed plane right now. And the Ray. Those will be on the table at the same time.
I'm dozing at the computer. See you after all the fun-lights flicker off tomorrow.
Rusty

Made some Microballoon filets tonight. They have instructions for all kinds of glue on the jar, so I followed the epoxy guide and mixed each part separately. Didn't know how much to use so I figured a tablespoon in each measuring cup. When I added the first half teaspoon of balloons, it was about a half a second before I stopped and put on a mask to breathe through. That's seriously light stuff. It is the glass type. I mixed and I added and I mixed and added and it grew and grew until I had to split it and use two cups. It's strange stuff and gets really stiff. It took a long time to mix. I finally combined them in the plastic cap from one of those jars that bullion cubes comes in, and it was full to the brim. I could have made fillets for more planes that I've ever built with that one tablespoon of each part of the epoxy.

So I got a stick and started gooking it onto the wing root. As I was doing that, I'm thinking, "Oh good lord, what have I gotten myself into?" So I did as instructed and wet my finger in alcohol and slowly spread it out. And damned if it wasn't the most beautiful filet I've ever seen. As I went around the LE, it followed my finger spreading perfectly. Then the other side, but it started to stiffen about the time I got to the LE and around to the bottom. But with enough alky I got it spread pretty nicely. On to the tail. Hmmm, it had set too much. Ding, your time is up! Crap, now I have a still full jar-cap of useless epoxy and microballoons. Oh well. A little dab 'll do ya. And of course I couldn't resist touching one of my beautiful filets, so there's a fingerprint that should sand out just fine. And I'll do the tail Wednesday. Going flying tomorrow and don't usually do much shop work the evenings after flying.
But now I know how to use Microballoons, wonderful stuff. I don't think it'll even need sanding. It's glass smooth and evenly spread. Easy peasy.
Rusty

Sounds like pretty good stuff. Thanks for the writeup, make sure you post pictures of the fillets if you get a chance. I would like to see how that stuff works.

Ron

The pix don't really do it justice. This is before sanding around the edges to clean it up. But it did clean up pretty easily. Next time I'll mask where I don't want it. Sounds like a no-brainer, right. 

I spent 5 hours at the field flying today, so I'm taking the night off in the shop. This time tomorrow I expect it will be wearing primer. 






Getting down to the serious stuff.


And guess what... the backplate bolt on the inboard side if the Fox hits the cheek block. I'll have to cut a hole in it. I'll disguise it as a vent or something.

I was wondering why there is a hole in this plane.

JPvelo wrote:I was wondering why there is a hole in this plane.

Haha, I'm glad it happened to someone else.

That bottom backplate lug does that a lot and is definitely a Fox .35 signature. My Super Clown has the hole. The plans said to drill it out for a Fox .35

You can see it in front of my Fox Power sticker in this photo.

Ron,
I may have asked this before but where did you get checkerboard covering? I love that plane.

Jim

At a Hobbytown in Arkansas? Can't remember. I was traveling. I am pretty sure it was a Hobbytown though. It's Ultracote, that I know for sure. Dang expensive too. It was $30 or so a roll. Came in red also.

And guess what... the backplate bolt on the inboard side if the Fox hits the cheek block. I'll have to cut a hole in it. I'll disguise it as a vent or something.[/quote]


Rusty, you might just be able to hog it out a little with a large drill bit, you got depth with the extra doubler.

I installed my threaded 4-40 inserts into the beams last night. I'm Glad Jim pioneered this for me because I knew to open the holes in the plywood doubler so it wouldn't split on the way into the Maple. I sunk the inserts flush with the maple beam so they're recessed relative to the doubler. I wanted all of the threads inside of the hardwood bearer. No signs of the maple distorting, no bumps can be felt in the vicinity of the insert, and the test puddle of epoxy is good and hard this morning and the 4-40 threads are clean. The only thing, and it wouldn't be me if there wasn't a "thing," is that the first one I installed went in slightly crooked.  

I should have been using my T-handle hex driver, so I did for the rest of them, all straight. They went in to my practice holes in a piece of furniture maple fairly easily, so I wrongly assumed the beam maple would be similar. But they're more like granite. These are new thicker Brodak Shoestring bearers. It's not too crooked but I'll hog out the top front hole on the engine so as not to stress the crankcase. The engine actually slides all the way on like it is, but not without wiggling and coaxing. I don't want that for the final installation though. Also, once my Dural pad and nylon thrust angle pad are in place, I think the backplate bolt will clear the cheek block, so no signature Fox hole in it.

My 4-40 tap arrived in the mail yesterday, so I threaded the elevator's Sullivan 1-7/8" horn to receive the screw that goes through the ball link. That went unusually well. I'm determined to get the fillets finished tonight on the stab and around the doublers and cheek. And to put it to bed with a full coat of primer tonight so it can be sanded and shot with white tomorrow.

And that's all the Yakking for this afternoon.
Rustoleum

roddie wrote:Hey Rusty, did you pre-drill the threaded-insert holes in the engine bearers at an angle to match your nylon thrust pad? Maybe this is a dumb question...   but I'm trying to figure out how the screws will line-up with that angle in there? The screw-heads/washers won't sit flat on the engine mounts will they?

The washers are soft enough that they seem to conform when tightened, and I always use more than one on each bolt through the mounting wings of the engine. But no, I didn't and I never have before. But I do notice the washers are bent out of shape when I've disassembled in the past. I'm lucky to hit a straight-in angle. This time I bored them with the drill press. Anything more technical is asking too much of my skills. I don't use ultra hard stainless steel hardware. I've always assumed softer metals are less likely to suddenly work loose. Up until I got the Fox, I've never been overly concerned with distorting a crankcase though. Now it's on my mind.
Rusty

Don't worry, it should be fine. I run thrust angle pads and have never had an issue with the holes being straight.

Ron