Thorp Air Command - T18.net

I was told by a friend of mine and former T-18 owner that others had told him T-18 landing speeds, not approach, but landing speeds could vary from around 50 mph to 100 mph. I told him I thought that was a bit more of a spread than I could believe, notwithstanding the fact that they are amateur built aircraft.

Can anyone substantiate this wide margin?

Thanks.

Most experienced taildragger pilots aren't looking at the airspeed indicator at touchdown. That said, a touchdown below about seventy will be tailwheel first.

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Bob Highley
N711SH
SN 835
KLAL

Not a chance a properly controlled Thorp will land at 100mph. Approach speed, like any aircraft is 1.3 Vso. That will most likely be below 100 mph.
Cubes

Ditto on both. I have no idea what my touchdown speed is. I know it varies slightly between both of the Thorps I frequently fly. As Bob mentioned I’m not looking at the ASI when landing. Approach speeds are similar, you can literally feel if you’re too fast or behind the power curve. As Cubes pointed out it’s a simple math equation. The Thorp is one of the most honest flying airplanes I’ve ever flown. Still baffles me as to how it’s gotten a rep as anything else.

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

Yep, there is no way I could land at 100mph. I cross the fence at 80 knots (92mph), and that's the last time I look at the ASI. I stall at
62 knots (71 mph) , so 62 knots x 1.3 = 80 knots.

Cubes : The next time we have chow in SAN I'll tell you when I did land my S-18 at 100 mph at KSEE ! No chance for a go around . Believe me it was NOT a planned event .

RB

Yiikes, if I crossed the fence at 80 kts in my T18 I would be through the fence at the other end of our 3000' grass strip. The magic number for me is as Cubes states (1.3vso) this gives me 67 kts over the fence then I close my eyes (just joking). Even thats too fast if I'm light so I'll use the third notch of flap which I have never blocked off and about 62 kts ias. I stall 52 kts ias full flap.

Tony Schischka

T18C
ZK-VMS

In calm air or direct head wind with 40 degrees of flaps:
3 pt - 58 mph ias
Wheel - 60 mph ias

Wheel landing can be done as fast as you like.

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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 want to make sure folks are NOT routinely using flaps 40. JT wanted us to eliminate that ability. I, myself, experienced the tail stall he was worried about on my very first T18 flight in 98.
Cubes

I think everyone should read up on the "bunt" in the news letters. There is some good information there. In particular, Lyle Trusty wrote a good article on it in #110.

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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

The 50 mph is wildly optimistic, perhaps some fellow whose ASI is well off (not uncommon with experimental airplanes). The 100 mph perhaps came from some fellow with a very heavy T-18 with poorly constructed wings giving scary stall characteristics, who was based at an airport with a 10,000' runway, with some exaggeration thrown in for story telling effect.

The CAFE test recorded wheel landings at 78 mph in a heavy T-18.

No idea what she touches down at, I'm not looking and the ASI starts increasing as the pitot enters the prop wash. I fly the final turn at 90 MPH and try to slow to 80ish crossing the fence. Any slower and she starts to feel really tail heavy until you get into ground effect. Annoyingly, once in ground effect, she feels 10 knots hot... (probably poor technique ).

-Andy

When my pitot tube was still on the tail the airspeed indicator bounced around a lot at lower speeds. Moving it out to the wing was a big improvement. I have since installed a Garmin G5 and it shows up well on GoPro video which has allowed me to learn my touchdown speeds.

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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

Best landing I ever made in a T-18 was with an inop ASI .

RB

I agree. Pitot tube angle in relation to the airflow can have a huge impact too. I noticed the other day the L-4 indicates a difference of about 17 mph between taxiing with the tail up and the tail down while my ground speed (gps) remained the same.

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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