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Old 09-23-2006 | 09:40 PM
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50+AirYears
 
Joined: Jul 2004
Posts: 1,647
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From: Irmo, SC OH
Default My fifth (B)ARF!

Anybody who has read posts of mine knows that while I have no problem with people buying and flying ARFs, I personally prefer to build. However, Tuesday, I broke down and bought my fifth RC ARF, a Goldberg Skylark 56. Did it because I've liked the design since it first came out, and was also curious to see if ARFs have gotten better since the last one I bought somewhere around 1995. I currently feel I will have it ready to fly in about four more days.

There are a few things I found out that are better than my last ARF, especially the fact that it seems all the joints are well fitted and adequately glued. I've seen ARFs that were apparently only spot glued with what looked like a hot-melt crap.

Instructions are written in understandable English. About the only missing part is a single 3.5 mm wing hold down bolt. The plywood seems decently firm, unlike other ARFs I've had that had plymush.

It still has a brittle wire instead of the nice American quality wire for pushrods and landing gear. In fact, I tried putting "Z" bends in three pushrod wires, and had the wire crack at a bend on each one. Luckily, an LHS had DuBro 1.5 mm threaded rod which fit the ends of the clevises quite nicely, and easily takes "Z" bends without breaking. Also, on one of the last ARFs I bought, the clevisses, although threaded, slid onto the threaded rod.

Tuesday night, in about 2 hours, I inspected the parts, joined the wings, used a heat gun to remove wrinkles, hinged the ailerons onto the wings, mounted the two aileron servos and the control horns. Wednesday morning, I sprayed the engine, radio and tank compartments with 2 coats of Lustercoat, and installed the aileron pushrods. That took about 20 minutes. After I got back from work, I spent about another 30 minutes to install the main LG and join the elevators to the stab. This morning, I spent about 1.5 hours total to make up and install the pushrods, glue the stab and fin to the fuse, Lustercoat an engine mounting plate, add elevator and rudder control horns, nose gear, and the elevator, rudder, and throttle servos.

I am still leery of the plywood for the firewall. Although harder than the ply I've seen in a lot of other ARFs, it is still only three ply, not the 5 ply I would use by choice. I am hoping that the lg blocks are reinforced with ply gussets on the ribs, not just mounted in balsa ribs like others I've seen.

I am also leery of using #6 sheet metal screws to mount the engine into the wood bearers. If there is enough room, I may try to put in threaded inserts for 6-32 machine screws.

I had hoped to use either my Fox 45 or 46 for power, but the fuse area is too narrow. Since all my Fox 40s which would fit are in use, I seemed to have a choice of an OS Max 40, which is a reliable engine, but with over 2000 RPM lower power than the Fox, or a Magnum 40 I bought from a Co-op I mentored, with which I am not too familiar. However, when I got the Dubro threaded rods, I also picked up an Italian made ST 40 that the proprietor was willing to let me have for $45. My other choices were to use the ST 51 I have, or buy a ST45. If this plane is as efficient as the original kit (Fully aerobatic with a Fox 25), it doesn't need the 51. In fact, probably the 45s would have been more power than needed.

Anyway, if it rains Sunday, the plane will be finished after the Brown's game. Otherwise, Sunday will be a flying day, and I will need about two more days to finish it.

I kind of feel like the time I was part of a team that built a computer based data collection system to use on test vehicles, then a new owner said we had to switch to a corporate standard plug together off the shelf component data collection system. It didn't do more than about 80% of what our system did, and was more difficult to set up and operate. Also, there wasn't the satisfaction of seeing something you helped design and build working, and even outperforming more expensive commercial units. It's nice, but the system we designed and built was nicer, better, and more emotionally and intellectually satisfying.

That's kind of how I feel about ARFs.