The T-18 design was originally developed with the
Lycoming 0-290G (ground auxiliary power unit) in mind, by John
Thorp. Which was easily converted to a Lycoming 0-290D engine
producing 125 HP.
The T-18 is an all metal 2 place side-by-side
high performance aircraft. Control response is exceptional and
control forces are well harmonized. The T-18 is a very capable
cross-country airplane. It will carry 2 people, 80 lbs. of baggage,
and depending on engine and prop, can cruise around 180 mph.
Powerplants range from Lycoming O-235 (115hp) to IO-360 (180).
The T-18 was designed to be built from twelve 4'
x 12' sheets of aluminium ranging in thickness from 0.016 to 0.040.
Ribs and fuselage frames were designed to be hand formed with a
mallet over plywood form blocks. Simple aluminium angle extrusions
are used for stringers and longerons. The main wing spar caps are
made from 1/4 "U" channel on top and angle on bottom with flat sheet
for spar webs.
John Thorp designed the aircraft to be small, yet
strong with excellent take-off and climb performance. The landing
gear is a simple "A" frame of heavy wall 4130 steel tubing, heat
treated to 180,000 lbs./sq. in. and bolted to the firewall with (3)
3/8" bolts. The engine mount is also attached to the "A" frame
allowing landing stresses not to be transmitted directly to the
fuselage. This landing gear system has proven to be rugged and
durable. The T-18 incorporates the "flying tail" which John Thorp
held the patent for. This design also incorporates a sliding bubble
canopy, like a fighter style.
The T-18 is a very historic aircraft. It was one
of the first all metal homebuilts. It was the first homebuilt to use
the stabilator or all-flying-tail. The stabilator was designed by
John Thorp and was later used by Piper on their line of Cherokee
aircraft. Today you can see the extensive use of this design on
military aircraft. The T-18 was the first homebuilt aircraft to fly
around the world. It was also the first homebuilt airplane to fly to
both the geographic and magnetic north poles. The legendary Don
Taylor completed all of these feats in the early 1970's. His famous
T-18 is now on display in the EAA museum in Oshkosh, Wisconsin.
T-18 plans are available again through Eklund
Engineering. They are also developing a kit version, using laser cut
parts and of course John Thorp's matched hole tooling concept. The
laser cut parts are beautiful and it promises to be a wonderful kit.
For more information contact Eklund Engineering at: firstname.lastname@example.org
or by phone at: (209)727-0318
No other homebuilt has done all the things that
have been done by this airplane. It is no doubt one of the best
designed aircraft in the world.
T-18 Designations / Models
The original design by John Thorp in about 1963
The original T-18 fuselage design, but incorporating Lu Sunderlands
new Convertible or folding wing. Plans were available through John
Thorp. The folding wing was a supplement to the original T-18
drawings. The plans were taken off the market in 1984 when John
Not many of these exist, but is the wide body version of the
fuselage as designed by Lu Sunderland, using the standard T-18 wing
platform. Plans were available through John Thorp. The wide body
modification was a supplement to the T-18 drawings. The plans were
taken off the market in 1984 when John Thorp Retired.
This is the predecessor to the S-18. It is the wide body version of
the fuselage, and also the Convertible or folding wing as designed
by Lu Sunderland. Drawings were available from John Thorp and they
contained supplements for the fuselage and wing modifications. The
plans were taken off the market in 1984 when John Thorp retired.
This is my own designation for this model and I hope it will be
accepted. This model uses both the standard fuselage and the
standard wing plan form, but incorporates the LDS airfoil designed
by Lu Sunderland and used on the S-18. There are no actual drawings
for the "L" version, as builders have taken it upon themselves to
make the airfoil change.
This is the redesigned version of the T-18 by Lu Sunderland. A
complete new set of drawings were done and offered in 1985. It is
basically the T-18CW
Lyc. HP Range180/125-180
distance, ground roll
rate of climb
landing distance, ground roll
limiting and recommended speeds
manoeuvring speed (Va)
never exceed speed (Vne)
stall, power off (Vsl)
landing approach speed
All specifications are based on