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Old Jan 22, 2013, 07:00 AM
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USA, NH, Alstead
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Starting to look like a plane

The fuselage is rolling along. Well, not quite rolling, but it could be if I put on the wheels.

I decided I needed to access the fuel tank from the cockpit so I made a round hole in the back of the compartment. When I got everything together I realized another bulkhead was in the way. It slowly dawned on me that the designers figured the fuel tank would come out through the hole in the firewall.

I screwed up on the engine mounts. I just glued them in and figured I'd deal with it later. I knew they were too narrow but figured I'd just open them them up a bit by removing some material. But what I didn't focus on was that I wanted to mount the Saitio 100 inverted. With a typical plastic mount no problem, but here attaching the engine to the bottom of the rail is going to lower it about 1/2". Luckily the engine will drop through the mount from the top once I widen it so it will wind up being too high by the thickness of its mount, about 3/16" I'd guess. I think that will be OK, fortunately. It my major faux pas so far.

The cabane set up is scary. There are precut notches that the plywood/wire assemblies sit into. Their size needs to be "adjusted" quite a bit so it is possible to get one side different than the other. I looked at it from several angles and tried to measure best I could and then glued it. I probably should have actually mounted the wings at this point and then fitted the brackets with the wings mounted. But the fuselage was not ready for the bottom wing mount at this stage. We will see. Fingers crossed.

I have been a bit concerned about the strength of the landing gear. The plans show optional wood dowels to form an inverted V between the the axle end of the gear and the middle of the fuselage, just for looks. I decided to make a wire V from 1/8" piano wire that will be attached to the bottom of the fuselage with some type of spring steel clip that will allow some, but not a lot of movement. It looks and feels like it adds a lot of support. Wrapping three landing gear pieces with wire and soldering was a pain in the butt.

Stringers go in little notches and are, interestingly, in a diamond pattern. Can't imagine putting these in without CA.

Well, onward and forward. E.J., I hope I am clearing a path for you. I am thinking of you when I post my screwups so maybe you can avoid some of the pitfalls, though you probably wouldn't make them in the first place. I've built a half dozen of these Bipes and every one is quite different in terms of the construction of both the wings and the fuselage. Building is like a chess game, and you kind of need to be about three moves ahead.
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Old Jan 22, 2013, 07:37 AM
Hamburger Eatin' Fool
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Traverse City, Michigan
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Things are looking good !

I, too, wanted to mount my engine inverted. When I saw how much work it created, I changed my mind.
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Old Jan 22, 2013, 08:00 AM
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Thanks Tom.

Indeed. There are lots of ways to do things, but you really have too look ahead. If I had looked far enough I might also have mounted my engine upright. To get it perfect inverted would have required moving the main engine mounts, and that is fairly involved in terms of making new notches in all the bulkheads. Alternatively you could put a regular firewall on and not use the maple mounts, but I suspect they add strength to the structure. Plus, with a regular mount the fuel tank would have to come out through the cockpit end. That would pretty much involve obliterating the bottom of the bulkhead right behind the one where I made the round hole. Plus probably the servos mounts might have to be relocated. Anytime you make one change you make another.

Fitting the Saitio 100 is a just barely affair as it is quite a bit longer than the 2S the kit was designed around. Always the case with the rear carb Saitos.
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Old Jan 22, 2013, 08:08 AM
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You have just stated the reasons that I decided to build the model basically as it was designed. Every change that I wanted to make, necessitated 3-4 more more, to make it work. In the end, I didn't feel that it was worth the effort.

The top wing mounts, and the N-strut mounts, are easy mods that don't have far reaching complications. It seems that any fuselage mod will take you down a troubled path.
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Old Jan 22, 2013, 08:12 AM
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Originally Posted by u2builder View Post
Well, onward and forward. E.J., I hope I am clearing a path for you. I am thinking of you when I post my screwups so maybe you can avoid some of the pitfalls, though you probably wouldn't make them in the first place.
Already keeping notes.

EJWash
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Old Jan 22, 2013, 09:30 AM
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You have just stated the reasons that I decided to build the model basically as it was designed. Every change that I wanted to make, necessitated 3-4 more more, to make it work. In the end, I didn't feel that it was worth the effort.
I've come to the same conclusion.

Since getting back into the hobby I've collected several "classic" kits. Of course, these models were designed around the available hardware of the time-period. Not an issue for the most part with present bits-n-pieces, but is presenting issues with modern-day engines depending on how they're mounted.

Laying-out model plans on a table and devising how to do certain things during the build is a decompressing ritual with me. In the case of the Waco, I will be installing an OS FS-91 Surpass I have on-hand. Using this engine presents two mods that will have to take place. 1- the length of the engine puts the rear-mounted carb right up against the bulkhead, and, 2- the models engine mount rails are too narrow (1-1/2" wide) to accommodate the with of the engine's crankcase mounts (1-11/16" wide).

First, I've concluded that mounting the engine upright is the path of least resistance. I'll have to wait until I get to the point in the build to see if the carb and intake will recess into the fuel tank area. Can't see much to pre-plan until then. As far as the engine mounting rails, I'll cove the needed clearance using my router table.

As mentioned, this kit was designed to use a .60 2-stroke engine. No large 4-strokers around back then. Out of curiosity, I measured my Sig Komet's OS 61FX 2-stroke. Well, I would not have been able to use this engine because the case is as wide as the FS-91. So, in at least this situation, to go with zero mods, I would have been chasing-down an engine of specific case size.

I also have a Pica T-28 (also designed by Dave Platt) that uses the same engine mounting design. Gonna keep those mods simple as well.

EJWash
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Old Jan 22, 2013, 09:32 AM
wood is good
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United States, CA, Marina Del Rey
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Originally Posted by u2builder View Post
...Building is like a chess game, and you kind of need to be about three moves ahead.
Much of the pleasure I get is from building it in my head, first.
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Old Jan 22, 2013, 09:45 AM
wood is good
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United States, CA, Marina Del Rey
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Quote:
Originally Posted by EJWash1 View Post
...Laying-out model plans on a table and devising how to do certain things during the build is a decompressing ritual with me. In the case of the Waco, I will be installing an OS FS-91 Surpass I have on-hand. Using this engine presents two mods that will have to take place. 1- the length of the engine puts the rear-mounted carb right up against the bulkhead, and, 2- the models engine mount rails are too narrow (1-1/2" wide) to accommodate the with of the engine's crankcase mounts (1-11/16" wide)...
Early on is a good time to mock up the motor mounting. I like to use transparent overlays of the motor outline to try different fitment arrangements before ever cutting or gluing any wood. I like to have the conceptual work finished, as much as possible, to avoid painting myself in a corner.
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Old Jan 22, 2013, 09:51 AM
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Much of the pleasure I get is from building it in my head, first.
Yeah, but I am not a good chessmaster, this fuselage is quite a bit different than anything else I have built, and the plans and instructions make the visualization process a bit difficult.

The reason I decided to go with an inverted engine is those darn cowl blisters. After goofing up the cylinder orientation on the first go on my Stearman, I actually looked at the plans and it appears that on the Waco the cylinder on the bottom is the one that is oriented vertically (at least this is what it looks like on the plans) plus of course the cylinder sticking through the cowl is less noticeable on the bottom.

I think it is all going to work out fine with the Saito.

I'll post a picture of the engine sitting on the mount as soon as the resin I coated the engine area with dries. I didn't want to gunk up the wood with all the after run oil I have slathered on my engine from storage.
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Old Jan 22, 2013, 11:06 AM
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OK, here are some pictures of the engine mount with the Saito 100. I used 3/16 ply for the side braces to make up for what I removed from the sides of the engine mount and obviously had to mount them on the top side. You can see that the engine is actually resting on the "bottom" side of its engine mount so the thrust line is getting raised about 3/16".

A bit off topic, but I finally got in a flight with my hexacopter after a fresh snow and before the wind came up so I figured I'd share it with you to prove I don't spend ALL my time in the shop. I also take time to pet my kitty.

http://www.youtube.com/my_videos_edi...1&feature=mhsn
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Old Jan 22, 2013, 11:22 AM
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Nice job recessing F1 and F2/F3 for the carb and intake tube.

EJWash
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Old Jan 22, 2013, 11:38 AM
wood is good
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United States, CA, Marina Del Rey
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Those cuts in the engine bearers aren't so bad.
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Old Jan 22, 2013, 12:16 PM
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Traverse City, Michigan
Joined Dec 2005
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Many of us like to have building companions. Mr Wally looks like an excellent assistant.
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Old Jan 22, 2013, 01:42 PM
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Off topic, but too lovely not to share with friends

I stumbled across this today. It is haunting and lovely. I am compelled to pass it on to all my friends.

Loreena McKennitt Never-Ending Road (5 min 58 sec)
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Old Jan 24, 2013, 11:10 AM
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Almost in the bones

The Waco is starting to look like an airplane.

I completed the upper fuselage and sheeted it and also fitted the wings.

The sheeting went great. The Waco is sheeted with 1/8" balsa, and the Pica balsa was really excellent. Wetting it with Windex it was easy to form to fit the curved fuselage. The cockpit opening was precut which was nice. The thick balsa makes a very strong fuselage. Very little sanding and almost no filler is needed. It may be the best sheeting job I have done, or put another way, I didn't have to redo anything, which is rare. The 3/16" strings result in a pretty stiff tail section too. Everything was done with medium CA.

My most pleasant surprise was the fact that the both wings fit rather perfectly, and the cabane wires and socket ends lined up perfectly with the holes I had predrilled. The wings are parallel to each other and spaced properly at both the front and back. I am actually fairly surprised it came out as well as it did.

Now I need to tackle the N-struts and their brackets to attach to the wing. Tom has suggested the kit supplied system is not too good, so I am going to try something else.

I got my Hayes 12 oz fuel tank and it fits perfectly with not much room to spare in the fuel tank box. The end of the tank is going to stick out a bit through the hole I made in the rear of the box after I "adjust" the diameter a little. I like having 12 oz of fuel on board for a model of this size with a Saito 100.

Well, that's it for now. Time to get the N struts done but it is oh so cold in the shop since temperatures are hovering around zero F outside.

The tailfeathers are just pinned on for now. I think I will cover them before attaching them.
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