T-40 Development


Gene Turner
T-40 History
T-40 Development
T-40 Photos
CAVU Books
Order Form


The T-40 prototype has gone through many modifications, from a single-place airplane to a well equipped, comfortable, two-place, fast cross country airplane.  Modifications are always made  with the goal of making the planes more efficient and easier to fly.  In one configuration the airplane had a T-tail, full-span flaps, spoilers, leading edge slats, and "buggy whip" landing gear. Later a canard was also installed. The canard version made only one hair raising flight then it was converted back to  the T-40A/B configuration.   At one time the airplane incorporated so many changes, the FAA required the airplane to carry a new model designation, T-77. Another modification was made requiring the designation, T-77A, a wide single-place version with a T-40 style canopy and tricycle landing gear.  Cruise speed  with a 150 hp  Lycoming was 165 mph (145 knots).   For pictures of  the various Models of the  T-40/T-77 airplanes see Section T-40 Photos.

 Model T-100D, MARIAH

In 1982 Turner Aircraft ventured into the ultralight aircraft arena with Model T-100 called Mariah.  Mariah was a light weight airplane designed to meet the needs of pilots who want to fly, but had no FAA flight physical or who could not afford to fly certificated airplanes. The T-100D was designed to meet the requirements of FAR 103, Ultralight Airplanes. The airplane had twin tails, pusher engine, three-axis conventional flight controls, tricycle landing gear, steerable nose wheel, and an enclosed cabin. Although the airplane met the design criteria and was very stable, the drawings were taken off the market due to the liability insurance problems.    

Surprise, in 2007 a surge of renewed enthusiasm came to life for the design spear headed by engineer who is employed by Lockheed Martin, Marietta, Georgia.  As a result Gene sold the design and manufacturing rights to Kenneth Adams of Adams Aviation of Dallas. Georgia.


The Turner T-40s and T-40As are high performance low-wing monoplanes constructed of Douglas fir and Mahogany plywood with fiberglass compound curved parts. All designs feature all-flying horizontal tails, steel leaf spring landing gears (either tricycle or conventional configuration), enclosed cabins,  and various four-cylinder engines. The T-40s can accommodate 75 to 125 hp engines and the T-40A, can be built with 100 to 150 hp engines. All models have folding wings and can be stored in a single-car garage.  Construction plans for these aircraft are made available to individuals for educational or recreational purposes only. The FAA must certify completed aircraft in the "Experimental" category.


FAA's  FAR 23.337, Load Factors:

Models: T-40,                                                   T-40A,                                                      T-40AS           


+4.4 g limit                                              +3.8g limit                                              +3.8g limit,
+6.6g ultimate                                        +5.7g ultimate                                        +5.7g ultimate
-2.2g limit                                               -2.0g limit                                                -2.0g limit
-3.3g ultimate                                        -3.0g ultimate,                                         -3.0g ultimate

FAR 23.561, Emergency Landing Conditions
All Models
Upward 3.0g
Forward 9.0g
Sideward 1.5g
Downward 3.0g
FAR 23.471, Ground Loads
The landing gears were designed using this FAA regulation as a guide. (The remainder of FAR 23 was used where appropriate.) Stress analyses and static load testing were used to substantiate the aircraft structure
Note: T-40 Series Airplanes are not designed for aerobatics. 


FAA FAR 23.337, Limit Maneuvering Load Factor X1.5 safety factor = Ultimate load:

 Dimensions                            Model T-40,                      T-40A,                                  T-40AS

Wing span                                    22' 3"                            25' 6"                              26' 8"
Wing chord                                   3' 6"                              3' 6"                                 3' 6"
Length                                          19' 9"                            20' 6"                               20'11"
Height (top of cabin)                       6 '0"                             6' 0"                                  6' 0"                                   
Wings folded                                7'10"                            7' 10"                                7' 10"
Cockpit width                               2' 0"                             4'
0"                                   4' 0"


Wing                                             75 sq.ft.                       90.0 sq.ft                            96.2 sq.ft.
Flaps                                            9.9 sq.ft.                      9.9 sq.ft.                              9.9 sq.ft.
Vertical tail  area                         9.6 sq.ft.                       9.6 sq.ft.                               9.6 sq.ft.
Horizontal tail area                      11.34 Sq.ft.                   12.0 sq.ft.                             12.0 sq.ft                           Weights
Gross                                          1140 lbs                       1580 lbs
                             1650 lbs
Empty  (Prototypes)                      850 lbs                        1050 lbs                             1100 lbs
Useful load                                  320 lbs.                        530 lbs                               550 lbs
Fuel                                            108 lbs (18 gal.)           144 lbs (24 gal.),                  80 lbs (30 gal.)
Baggage                                     20 lbs                            30 lbs                                 30 lbs


Vmax Max speed          170 mph                      175 mph                      180 mph             

Vcr -  Cruise speed          143 mph                       147 mph                     155 mph

Vs - Stall Clean                 55 mph                         56 mph                       60 mph

Vso Stall, Flaps             49 mph                         50 mph                       54 mph

Va Maneuvering speed   120 mph                      125 mph                     125 mph

Vd Red line                   220 mph                       220 mph                     220 mph                

Vgust                              145 mph                       140 mph                     140 mph

Range Max No wind       482 miles                      625 miles                   413 miles

Rate of Climb  @ SL        1,000 ft/min                  1,300 ft/min                 1,260 ft/min

Service Ceiling                 15,000 ft.                     14,000 ft                      14,000 ft  

Takeoff Distance               600 ft.                          950 ft.                           850ft  

Landing Distance           470 ft.                          1,100 ft.                       1,400 ft.


NOTE:  Performance figures based on the following: T-40 with conventional landing gear,  T-40A with conventional landing gear and 125 hp engine, and the Super T-40A (Bubble canopy) with tricycle landing gear and 150 hp  engine.


 Top of Page