Thorp Air Command - T18.net

How does one determine if the aircraft has the long or short gear legs?
Thanks

Take a look at the 515 drawing and compare measurements.
Cubes

Thanks Cubes, so if the measurement match the print, the ldg is the short gear Correct?

Correct. If you have T18 drawings. If you have S18 drawings, it is long gear. Good question.
Cubes

Is anyone running the S-18 gear legs on a T-18? Longer gear on a longer fuselage makes sense to me but longer gear on a short fuselage makes me wonder if the change in wheel position in relation to the center of weight and shortening the distance between the mains and the tail could alter the ground handling characteristics.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I have replaced my original T-18 landing gear with S-18 gear from Cubes. It fit right on, including the engine mount. I was surprised how well it fit, with only a small amount of grinding and file work.
The legs are a bit longer, I had to make new gear leg fairings and brake lines.
Sorry, I have not flown it yet.

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Scott Emery
EAA Chapter 326
T-18 N18TE

I have long gear on my T. It works great. The longer gear, combined with a Trusty tail spring allows you to land much slower. The Trusty tail spring puts the tail wheel 9 inches further aft and lowers the tail by two inches. All of these things combined to make landing much easier and more controllable.
Cubes

It is hard for me to get an accurate indicated landing speed because the indication fluctuates when I get slow but I land around 50 mph no matter which attitude I touch down in. How much slower is possible by extending the gear length?

I should note that mine has extensions installed that move the wheels down without changing the station location. I have the original flat spring tailgear with a Homebuilders fork and tailwheel. The airplane is quick to respond on the ground but I don’t consider it squirrelly.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Not sure I could throw a number at you. I will say that when I three point, I no longer hit the tail wheel first. The wing still stalls at the same speed, but the airplanes attitude in a three point is right where it needs to be.
Cubes

Except for maybe a couple of times when I first got the airplane, I don't think I have ever hit the tail first on landing. I do tend to wheel land most of the time so maybe my 3-point landings qualify as wheel landings. I land when the airplane quits flying (not necessarily stalled but not enough lift to fly either) and the airspeed difference between having the tail up and having the tail down at that point is very small with my airplane.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I have 2800 hrs on my T-18 with the longer gear. Adding the Trusty tail spring only made it better. Long gear on a T-18 is a non-issue.

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Bob Highley
N711SH
SN 835
KLAL

The long gear does get you a small amount of additional prop clearance, something I needed for where I hanger.
Phil
118BC