Thorp T-18

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Little Scrapper

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Just posting this for fun. It’s not often we see great photos of a Thorp T-18. This was just posted on a Facebook group and I thought WOW! what a great shot of a neat airplane! I don’t know Jack squat about aluminum sheet metal but I believe these are somewhat simple to build? Pop riveted? Going from memory I’m probably wrong. Anyhow, hope you like this it sure is a looker!

Photo credit: Scott Stine. Owner is Lee Walton in Olney Illinois.
8F070A75-542B-4505-AD5B-5C5271E80E87.jpeg
 

Wanttaja

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Solid rivets, matched hole construction. Some real smarts went into the construction process. The cranked wing isn't merely for aerodynamics; each section is the width of a sheet of aluminum so you don't have to make a long cut, just wrap the sheet around the ribs.

Knew a guy who built one using a hammer as a rivet gun, and a long bar of solder to shape the aluminum.

Great as used airplanes. You get performance almost equal to an RV-6 for about a third of the price. They're a little cramped inside, though.

Ron Wanttaja
 

Little Scrapper

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If anyone here is ready to build, let me know. I have a set of plans.


BJC
I have no interest on the plans for building but I’m curious. Are they decent plans as far as aluminum airplanes go? I never hear anything about this airplane soI have no idea. Hand drawn?CAD?
 

scramjetter

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It's a beautiful airplane. The S-18 was a Thorp sanctioned widened variant with a different airfoil. The outer dihedral on the S-18 starts further inboard. Like Ron said, it's kind of cozy inside.
 

BJC

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Excellent plans hand drawn to typical (of the time) production standards. All parts are shown. Possibly could be a little intimidating at first glance to someone whose only experience is assembling a kit.

The matched hole technique is ingenious.

[Edit: The set that I have is the S-18. That is an improved T-18. I gave away the T-18 plans earlier. I personally like the S-18 better. S drew the plans for T.]
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BJC
 
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TFF

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Designed for the homebuilders. Straight wing center keeps the builder from having to build a complex center section.

When it came out the only thing comparable was the Midget Mustang single seat. RV 3 was another ten years away, give or take. Much easier to make. It’s what all the O-290Gs were
invented for.

It is a hot plane, a Cub guy will have to step up. A Bonanza guy, not so much. But given original time it came out, the The builders were Cub fliers and that surprise them. A lot of homebuilts were like that. Today training is better in that respect. Lots of avenues for type training.

I have an 8 ft brake but I don’t have any aluminum and my RV buddy moved away. I would have to go buy a rivet squeezer since I can’t borrow his.

It’s usually the second type I seek my first day at Oshkosh. First Tailwinds, second T-18s, third Falcos. Biplanes are a different attention level. Usually the T-18s are north of the Tailwinds and the Falcos are south. I have to back track. Miss it.
 

BJC

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They are solid flush rivets so there's a couple extra steps at every hole.
Yup, that’s how everyone builds them, but the original concept per Thorp was pulled rivets, O-290 GPU, fixed pitch prop, open cylinder cowling and open cockpit. I’ve never seen one built that way.

My first ride in an HBA was in a T-18 at Rockford, circa 1966 or 1967.

[Edit: Back then, one could line up beside the runway and get a ride in the two seat homebuilts. Homebuilts and restored antiques (not “classics”) flew throughout the day, and there was no music or incessant shrieking of announcers.]


BJC
 

Little Scrapper

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Correct me if I’m wrong but In the museum on the wall there’s a famous airplane that flew around the world. Possibly 70’s/80’s? Red and white? I think it’s a T-18?
 

TFF

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From what I have read, when Thorp first presented the T-18 concept, it was open cockpit and cowl. I want to say at an EAA meeting. I think he was wishy washy on it. A couple of weeks later someone who was at the meeting came up to him with a sketch with an enclosed cowl and bubble canopy and asked what he thought. Something said like “that’s what it needs. “ I think the guy ended up building the first one; building as drawings were drawn or requested when stumped. Nowadays people can’t decide if they need a -3 or a -4 rivet and call the factory.
 

Bill-Higdon

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Solid rivets, matched hole construction. Some real smarts went into the construction process. The cranked wing isn't merely for aerodynamics; each section is the width of a sheet of aluminum so you don't have to make a long cut, just wrap the sheet around the ribs.

Knew a guy who built one using a hammer as a rivet gun, and a long bar of solder to shape the aluminum.

Great as used airplanes. You get performance almost equal to an RV-6 for about a third of the price. They're a little cramped inside, though.

Ron Wanttaja
Orinially it was US Shoe Pop rivets used for most of the structure
 
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