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Old Feb 25, 2013, 09:41 PM
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Intrigued.
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Old Feb 25, 2013, 10:58 PM
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Phil U's Avatar
Australia, NSW
Joined Feb 2013
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Just going through some of the earlier build pics. I notice you used a 1/4" engine mount. I wasn't sure what would work here, so used 1/8" ply epoxied to a thin sheet of aluminium. I figured that would give it strength and rigidity. Seems to work ok.

Interesting to follow your steps and come across similar build issues. The aileron servo was also a sleepover problem for me. I ended up, like you, gluing in a couple of blocks, but then I glued a ply tray on top of them and just mounted the servo upside-down with a side arm mount to pick up the rod connection. (Actually it's only upside-down when you're mounting - once the wing is on it's right side up). From memory I think this meant reversing the servo throw direction, but that is irrelevant with modern transmitters.

My next build is going to be an Astro Hog from a kit. I want to see how a kit compares with a scratch build (and also want to save a bit on costs this time round). I'm also hoping the Hog will be modernised so that I can see how things are done these days compared with 1969.

Hopefully I will get this thing in the air on Sunday, although I suspect my wife has other plans. I've replaced my rudder and elevator piano wire rods with gold-n-rods, amazingly without breaking anything. Wish I'd known about these things from the start - they are a great product, as are so many of the modern materials. No soldering - hooray!
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Old Feb 25, 2013, 11:26 PM
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Australia, NSW
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I went with rubber band wing mounts for mine for one reason: I couldn't work out how I could sand a smooth surface between the soft balsa sheeting and the hardwood bolt mounts, particularly as the dihedral gets in the way. What's the secret?

Also a guy at the club recommend this allen key extension business for the needle valve but I can't find one that even remotely looks like fitting into the needle valve hole - have tried the very annoying US imperial sizes and the proper metric ones. What's the go?
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Old Feb 26, 2013, 01:01 AM
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Interesting thread!
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Old Feb 26, 2013, 01:08 PM
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Phil,
What kind, size and brand of engine are you using? Maybe with that info I can help you with the needle extension. On OS Max the needle has a small hole and a transverse set screw that allows for a wide range of wires or Allen wrenches to be inserted. I will post a picture in a day or so when I get home to photograph something. I felt the ¼’ ply mounting plate with six bolts was more than enough reinforcement for the engine mounting, would not even give it a second thought. The plywood supplied was very high quality aircraft ply.

As far as wing mounts go I place the plywood mounting plates far enough inside the fuse so they will not touch the deepest part of the wing when the wing passively sits on the fuselage wing saddle (sides). The wing bolts simple exert downward pressure which snug’s the wing down to the saddles, the wing actually never touches the threaded plates, and it doesn’t have to. You do need to re-enforce the area where the bolt contacts the top side of the wing, either a contoured plywood plate or a cavity filled with resin and micro-balloons. This way when you cinch the bolts tight you don’t deform or crush the wing sheeting. I like to use the bolt down method because the wing once aligned will always return to that spot when remounted, and it looks good. A very complete step by step process is covered in one of the Harry Higley how to books (Harry’s Notebook).http://www.harryhigley.com/Books2.htm It covers mounting the wing and walks you through the clamping, aligning, drilling and tapping. The intimate fit to the wing saddle is achieved using the MonoKote film on the wing and a layer of micro-balloons and resin or epoxy on the wing saddles. (pictures earlier)

When you rubber band a wing down you need to use at least 6 or 8, #32 rubber bands. That can be enough pressure to crush the sheeting or severely notch the trailing edges, so take care that the wing trailing edge is not hanging over the back edge of the fuse mounting area. The cool thing is that we have all been there before; so I hope you have an experienced flier who can help check every thing out for that first maiden voyage. Good luck
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Old Feb 26, 2013, 03:50 PM
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Australia, NSW
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some pics

Here are some pics of mine at the field.
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Last edited by Phil U; Feb 26, 2013 at 11:22 PM. Reason: more pics
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Old Feb 26, 2013, 03:56 PM
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Grass? In Arizona???

Phil, you have a nice grass field....I miss those days
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Old Feb 26, 2013, 07:22 PM
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Quote:
Originally Posted by tailskid2 View Post
Phil, you have a nice grass field....I miss those days
Thats a cool scale airplane
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Old Feb 26, 2013, 07:25 PM
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Phil, That engine looks like an OS AXL series, didn't it come with a cable and knob needle extension?
Plane looks great covered, would have never occured to me to put servo in upside down, seems like it might be hard to get to the clevis?
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Old Feb 26, 2013, 10:01 PM
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Great thread, guys, I'm really enjoying all the fine work and discussion.

Phil, can you give us the weight of your plane now that it's finished? I'm guessing you will like the power of the modern .46. I will eventually be choosing between an old Enya 60 II and a four stroke in the .52 to .62 range.

Jim
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Old Feb 26, 2013, 11:52 PM
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Australia, NSW
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My engine's an OS Max 46 AX-2. There was a small piece of wire cabling in the box which has me scratching my head. Clearly there's something going on here I'm not aware of. The needle has a hole in the end and one on the side, which I had presumed was for measuring rotations.

I'll try to remember to get the weight tonight - will be a bathroom scales job though.

We do have a nice field here - out of the way too. We get plenty of rain on the coast north of Sydney.

The servo was a little tricky to hook up, but I just inserted the clevis before screwing it to the mount which gave me a little more wiggle room. It actually wasn't too bad at all. The hardware I'm using I doubt is the best for the job, but it's all they had in the shop at the time.

Also I've just had my old plans scanned and will be looking for a site to upload them to. These things are rarer than dodos it would seem.
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Old Feb 27, 2013, 12:07 AM
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This model is going to look great with the floats on. I'm a bit jealous.
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Old Feb 27, 2013, 08:13 AM
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Phil, I would suggest sending them to Outerzone...http://www.outerzone.co.uk/index.asp. They are building a really good collection that a lot of people use. Someone is really going to appreciate your plans.

http://hippocketaeronautics.com/ is also a good place. You probably have to join, which is not a big deal. Their collection is smaller. Wouldn't hurt to do both, but if I were putting it in only one place it would be outerzone.

Thanks for showing the servo installation. I was thinking of putting a mini servo in there on its side, but haven't checked dimensions. I've got some other projects in line ahead of this one.

Mine is 5 lbs covered, primed, with wheels and engine but no radio. I'm thinking it should come out around 6 lbs finished. If so, a .52 four stroke, or an antique 60, would be plenty.

Jim
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Old Feb 27, 2013, 09:29 AM
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United States, KY, Bardstown
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Sanding Epoxy

I find sanding epoxy to be very difficult. How do you do it? Also, which ca glue do you use on wings etc? The thin or medium glue? When you mix your balloons and
epoxy, what ratio do you use? What minute epoxy do you use? How heavy are your individual lead weights? What is the glue you sprayed on the fabric for the center of wing reinforcement?
Probably more questions later. A great build to follow.
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Old Feb 27, 2013, 01:53 PM
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Quote:
Originally Posted by Bardstown Flyer View Post
I find sanding epoxy to be very difficult. How do you do it? Also, which ca glue do you use on wings etc? The thin or medium glue? When you mix your balloons and
epoxy, what ratio do you use? What minute epoxy do you use? How heavy are your individual lead weights? What is the glue you sprayed on the fabric for the center of wing reinforcement?
Probably more questions later. A great build to follow.
Okay let’s see Epoxy is very hard to sand actually almost impossible. So, on the tail pushrod exit tubes I used Epoxy 30 minute stuff mixed with Micro Balloons. I just keep adding balloons until it is the consistency I want, honey, peanut butter, doughy. I use peanut butter consistency for making fillets. When it comes to sanding epoxy I don’t think I can; but epoxy and micro balloons will sand fairly well with 60 or 80 grit paper and then finer from there.

A little compatibility conversation. If you mix Micro Balloons with epoxy and place it on wood you can NOT place a polyester resin finish over the top. Therefore I use polyester resin and micro balloons to make fillets on the fuse.
I just said that I use epoxy and balloons on the tail pushrod exits and this was a compatibility mistake. I was able to recover by coating the exits with thin CA cement and then re-sanding

On the wing center joint I used Zap finishing resin over the fiberglass cloth. This particular epoxy probably sands better than most. Some people like it to do all of there fiberglassing. I did not have any polyester lying around at the time and for a small quick job; I like the Zap product. The glue I used to tack and hold the glass cloth to place was 3M spray mount. I have also used 3M 77 building adhesive, but that stuff is fairly heavy and a little overkill.

The lead ingot weights I poured myself, they probably weigh between ½ pound and 2 lbs each it varies with the thickness. Some are thick some are thin.
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