Build Thread: UMX Texas A&M AG-1 from Air Trails 1952 - RC Groups
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Oct 24, 2012, 10:51 AM
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Build Thread: UMX Texas A&M AG-1 from Air Trails 1952


I'll soon be starting on a micro-sized model of the AG-1 for a contest in the Balsa Builders forum. Since it's a vintage design, it seems to make more sense to cover the build thread here. I'll be doing a little history of the real plane as well as the one my father built back then as part of the deal.

The thread is mentioned in this forum as well, right here: https://www.rcgroups.com/forums/show....php?t=1756062

If you're interested in reading up on the thread, here's the link: https://www.rcgroups.com/forums/show....php?t=1755366

Attached are some photos of the real plane and a low-res copy of the plans. I'll be building it at about 22" span. I found the photos on the web somewhere, and got lucky to find original plans which I had scanned.

Fred Weick designed the AG-1 first off to be safe to operate. Many of his design concepts, thought to be heretical at the time, are what make modern automobiles and aircraft safer today. The AG-1 was the forerunner of many ag aircraft (several of which he also designed).

He also wanted the aircraft to be maintainable by the farmers operating them. The all-aluminum skin, he felt, would be easier for a farmer to maintain with a pop rivet gun than a fabric and dope finish.

If you have any interest in history, you would enjoy reading what you can google about Fred Weick and the AG-1 (and related aircraft such as the Piper Pawnee). The man was decades ahead of his time!

Andy
Last edited by AndyKunz; Feb 22, 2014 at 07:34 PM. Reason: Adding pre-construction info and photos
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Oct 27, 2012, 01:01 PM
AndyKunz's Avatar
Quote:
Originally Posted by Steve_P.
Andy, just as a sidebar, the AG-1 airframe used to hang on one wall of a hangar at the old Bryan AFB near Bryan/College Station, Texas; the AFB was administratively under the control of Texas A&M University, and still is. George Aldrich came to the campus several times in '64/'65 to measure and take pictures of the AG-1 in preparation for publication of his AG-1 Duster stunter. I started college at Texas A&M in 1965 and helped move some of the AG-1 parts during the measuring. The AG-1 parts were hung right next to the original Fred Weick Ercoupe airframe, which is now at the Smithsonian. Steve_P.
I received this as a PM today. I thought it makes for some interesting info!

Thanks, Steve!

Andy
Apr 27, 2013, 06:41 PM
AndyKunz's Avatar
Well I'm FINALLY able to get started! I had a little delay this winter with a need to work with some club members to build a 150% Kadet (still not finished), and then I needed to build a model for an upcoming club contest https://www.rcgroups.com/forums/show....php?t=1867359

Since I'm waiting on insignia to arrive to finish that one, and that's all that's left, I figured I'd take advantage of today's rain and start on a model that has been YEARS in coming!

I'll be building it mostly per the plans, but already I've found problems with them! The formers don't fit! So you'll be seeing some kludges along the way as I find issues. The first one you can see already - the former in front was about 1/8" too short! I simply shifted the whole former up but had to cut new notches in the sides to do it.

Another thing - this is going to be my standard 100 sq in size. Power and control is stuff I scavenged out of a Parkzone Carbon Cub which happens to be the same size. Besides wanting to build this for my Dad, our full-scale glider club www.illinigliderclub.org has several members who bought the E-Flite ASK-21 and they need a towplane. The club's towplane is a Pawnee, and making a model of the Pawnee's predecessor just seems like a good fit. You'll see me making some mods to add a tow hook on this plane too.

Andy
Apr 27, 2013, 09:05 PM
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Not a whole lot more done tonight, but I did get the sides joined and ribs made. I won't be working on it until Monday afternoon at the earliest, and perhaps not then since the grass needs mowing.

That dowel you see in the nose is going to be the mount for the Park 180 motor. For now it's just a place-holder, keeping the nose pieces aligned. I also added a few stringers after this photo was taken, but we'll catch that next time.

See you all in church tomorrow!

Andy
Apr 30, 2013, 12:52 PM
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It looks like I'll be off this project until next Tuesday. Just too much going on between now and then. I have the covering on order, though, so at least a little progress is being made

Andy
May 01, 2013, 06:58 AM
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Andy,

IIRC, the AG-1 plan was in the first copy of the old Air Trails magazine that I ever bought, circa 1952. Inspiring!

Jim R.
May 01, 2013, 08:03 AM
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I have that copy!

Andy
May 01, 2013, 12:53 PM
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Do you want me to bring the thread into the second contest? It is eligible.
https://www.rcgroups.com/forums/show....php?t=1842080
Latest blog entry: RCM Plans Collection
May 01, 2013, 01:16 PM
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No, but thanks for the offer David.

Andy
May 03, 2013, 05:15 AM
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You're welcome, Andy. Nevertheless, as a modeler and Texas Aggie (class of 1980), I'll be cheering you on. David
Latest blog entry: RCM Plans Collection
May 19, 2013, 08:36 AM
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I finally had a little time last night to work on the AG-1 again. I'd like to have it ready in time for the JR AeroTow. That gives me a goal to shoot for.

The rib spacing is the same for all ribs in the outer panels, so I started by working on the left wing panel first. Nothing special, really. The wing tip is rounded on top and tapers up from the bottom, so the spars are extended past the rib.

I also did a little with the fuselage sheeting. Here you can see the top pieces going on. They are glued first to the sides (and a little to the straight parts of the formers). After that dries, they are bent over the rounded portions and meet in the center on the stringer.

Note that the nose sheeting has the grain rotated slightly. This allows for the sharp bend to run exactly down the grain, resulting in an easier and more-even bend. The wood won't "bow" any this way. I forgot to do that on the rear portion, so I expect a little waviness there when it's done.

That's about it for now. Some progress is better than none!

Andy
May 21, 2013, 08:44 PM
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The fuselage sides were curved over the top and glued. The seam isn't perfect but it works for me. I added the pieces on the cockpit sides. These need to be carefully fitted so that they use half the former thickness behind them, with the rest used by the parts already there. These had to be added separately as they would be a compound curve if I had tried to use either the front or rear portions.

The center section of the wing is drying now. The LG mount is hard balsa with a groove and hole. The legs will be .047 piano wire.

I'll just keep plugging away, a little each night. I gotta start on the tail soon, as well as mount the motor.

Andy
May 25, 2013, 09:05 PM
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Been working on the wing a little.

Here you can see the full span, about 22" x 4-3/4" (about 104 sq in). The spars are extended a little to support the tips, but you can see the way I removed 1/32" off the top of the spar to allow the 1/32" balsa sheet to be flush with the top of the rib.

It doesn't look like I'll have it ready for the AeroTow, but I'm still going to try.

You can also see the square stock I added where the servos will be mounted.

Andy
Feb 10, 2014, 09:41 PM
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I took a vacation from the AG-1 to build some other models. This winter I've been trying to clear off my "finish and fix" work bench a little at a time, and now I'm back on this.

Tonight I started by putting spar webbing in the center section and first rib bay of the outer panels. I changed my mind on this one, and will only be building it for R/E/T so the ailerons will remain uncut. That will save a little time (E-Fest is this weekend...) and also make for something different. The plane on the plans was originally FF, and even as a scale model it has plenty of dihedral.

While that was drying I moved on to the chin, which will become the battery and motor access hatch. I started by inserting a sheet of 1/16" balsa (it will be opened up later) between the formers. Next I wrapped some well-softened balsa over them and set it aside to dry. I like to use cellophane tape to hold these instead of pins, as the thin wood is very easily damaged by the pins and makes for filling work later on.

Meanwhile I worked on the stab, fin and rudder. These are all 1/8" balsa sticks. The elevator halves will have to wait until tomorrow.

Andy
Feb 11, 2014, 09:52 PM
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The receiver mount is in place now. It is moved as far forward as possible so I still have access to it from the open cockpit. The mount is simply a piece of wood spanning the open fuselage above the wing. I did it this way because I want to keep the settings from the Carbon Cub.

Tonight I also did a little more work under the hood. I added the plate which the plastic motor mount will screw to, opened up to give room to the motor, and added a little to the hatch.

The elevator was made from a piece of hard 1/8 x 1/4 balsa glued to some soft 1/8" sheet. This assembly was then sanded to a tapered TE and then trimmed to the proper outline and span.

During lunch we flew (7 degrees F!) one of my other projects from this winter, the Neo 180. This is an original Classic Pattern style plane with features glommed from several of the classics. It uses the same Carbon Cub brick. Watch for it in a future issue of Flying Models.

Andy


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