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Stearman PT-13A Kaydet

The Stearman Kaydet (also known as the Stearman (Boeing) Model 75) was a Biplane Primary Trainer with seating for an instructor and trainee, in inline open cockpits, and had fixed landing gear.  Several variants ofthe plane were built, primarily differentiated by they type of engine fitted.  Per Reference [8] the base PT-13, or whih 26 were built,  was fitted with a 210 HP Lycoming R-680-B4B radial engine.  The PT-13A variant, of which 92 were built, was fitted with a 220 HP ycoming R-680-7 radial engine. The PT-17 was a sinilar design fitted with Continental R-670 radial engines, and the PT-18 was a variant fitted with Jacobs R-755 radial engines.  The US Navy also operated these type aircraft under the desginations NS and N2S.  Export variants, designated the Stearman 76 were also sold to Venezuela, Brazil, Argentina, the Philllipines, and Cuba.  The type was also provided to Canada as part of Lend/Lease during WWII.  Per reference [8] this type was introduced into service in 1934, and a total of 10,626 were built.  

As shown in the images below distinguishing features of this aircraft including;
PT-13A

[Image Sources: US Government/Public Domain via Ref [8] - as annotated by this site]
N2S-PT13
        [Source: Ref [8] - US Government/Public Domain]
PT-17_PT-18_3-view_A
[Source: Ref [14] - Scanned from a US Government Document - Believed to be in the Public Domain]
                                                PT-17/PT-18 Variant

In order to try and better develop weight estimating relationships an effort has been made to estimate the length of the fuselage aft of the firewall, and the length of the engine section forward of the firewall based off scaled drawings.  Together these two distances add to a term called the "structural length" and do not consider any portion of the engine or propeller shaft the extend foward of the fuselage/cowling, or any empennage that extends aft of the fuselage structure.  The drawing below shows the current best estimate of these dimensions obtained from available drawings of the airplane and will be updated with any real world data that becomes available.  For any aircraft with an inclined firewall, an attempt has been made to locate an approximate center of this location.

PT13A Dims
                                                                Source References [2] [3] [8] & [16]

In the above images, dimensions in Black come from the source material while dimesions in Red have been approximated from the data available.

The table below summarizes the current data collected on this type aircraft, identifying sources for the data

    PT-13A Secondary Sources Notes
Primary Source   2

No of Crew   2

Engine:  


   Qty   1 5
   Model   R-680-7 5
   Displacement  (cu in) 680 5
   Power  


     Military (HP)


     War Emergency (HP)


    Normal (HP)
5
    Take Off (HP) 220 5
   Eng Dims  


     Length (ft) 3.09 5
     Width/Dia (ft) 3.63 5
     Height (ft)


   Base Engine Wt (lb) 500 5
Propeller  


   # Blades   2

   Dia (ft) 8.5

   Manufacturer  


   Type  


Wing  


   Span (ft)


   Root Thickness (%)


  (in)


   Total Area  (sq ft) 298

     Wing (less Ailerons & Flaps) (sq ft)


     Ailerons (sq ft)


     Flaps (sq ft)


Tail Area (sq ft)
3
   V Tail Area (sq ft)
3
     Fin (sq ft)  

     Rudder (sq ft)  

   H Tail Area (sq ft)
3
     Stabilizer (sq ft)  

     Elevator (sq ft)  

Total Control Surf Area (sq ft)


Length  


   Overall (ft)


   Fuselage (ft)


   Body  (ft) 24.75

     Body Depth (ft)


    Body Width (ft)


Fuel Tank Volume (gal)


   Wing Tanks (gal)


    FuselageTanks (gal)


Oil Tank Volume (gal)


Water Injection Fluid Tank Volume (gal)


Wetted Area (sqf) (sq ft)


Pwr Ldng (lb/HP) 11.97

Wing Ldng (lb/sq ft) 8.84

Struct. Des. GW  (lb) 2638

Ultimate Load Factor (G's)


Design Speed (mph) 125

Not to Exceed Speed (mph)


   


Total Struct Weight   1051

   Total Wing   444

     Wing    

     Ailerons    

     Flaps    

     Fuselage Carry-Through    

   Tail   72

     H Tail   52

       Stabilizer    

       Elevator    

     V Tail   20

       Fin    

       Rudder    

   Body + Eng Section + LG  


   Body + LG   535

   Body   274

     Fuselage    

     Engine Section    

   Landing Gear   261

     Mn Landing Gr   233

     Tail/Nose Aux LG   28

   Tail Hook  


   Booms  


   Nacelles    

Total Propulsion Weight   714

   Engine w/ Accessories   524

   Engine(s) as Installed   500

     Accessories   24

    Turbocharger(s)  


   Controls   11

   Propeller(s)   84

     2-Blade   84

     3-Blade    

     4-Blade    

   Starting System   28

   Water Injection System  


     Tanks    

     Piping Etc    

   Cooling System  


   Lube System   12

     Tanks    

     Piping Etc    

   Fuel System   55

     Tanks    

     Piping Etc    

Total Sys. & Eqpmt.   181

   Instruments   29

   Surface Controls    64

   Hydraulics  


   Electrical Equip   11

Electronics (Purple means incl in Furn/Gray in Useful Ld)  


   Arm Prov/Equipment & Armor  


    Furnishings   77

   Anti-Ice (If not in Furn)  


   Other /Misc  


     Hoisting Gear  


     Floatation Gear  


     Armor Plate    

     

Empty Wt   1946

Basic Mission Useful Load   688

   Crew   400

   Equipment  


   Oil   33

   Fuel   255

   Fuel & Oil Trapped in Systems  


   Water Solution for Engine Injection  


   Bombs/Torp Etc  


   Radio (if Not Included in Empty Wt)  


   Nav Equipment  


   Oxygen System  


   Armament  


     Guns & Ammo    

       Guns    

       Ammo    

     Pyrotechnics    

     Camera    

     Other    

   Other Useful Load  


Basic Mission GW   2634


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Rev 3-22-26

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