SM-2  Specifications,  First of the “Junior” Series airplanes


SM-2,  4PCLM Type Certificate number 48, Aug 1928. First plane delivered early 1928.

One SM-2 was used as a test bed for Kinner engine under Group 2 Approval 2-136.

Serial numbers 1000 to 1041

Factory Location:    Northville, MI

Number Built:          Up to possibly 41

Engine:                   Warner Scarab 7 cylinder, 150 -165 hp engine. 

Weights:                 Empty: 1516 lbs, Useful: 984 lbs, Gross: 2500 lbs

Cruise Speed:         90 mph

Fuel:                       42 gals

Oil:                         4.5 gals

Length:                   26 ‘  3”          Height:    7’  4”

Wing Span:             41’  5”           Chord:     75”

Airfoil:                     Clark Y                       

Factory Price:         $8500           (2018:   $122,540)


The Fuselage was a fabric covered, welded chrome-moly steel tubing with gussets at each junction.  It was streamlined by spruce and plywood fairings.   The wing was a fabric panel with box-type routed spruce spars with spruce and plywood ribs.  The wing struts were designed to provide for additional lift and were chrome-molly steel tubing formed to a Clark ‘Y’ airfoil by balsa wood fairings.  Ailerons are Freise balanced-hinge type and were made of welded steel tubing. The empennage was a fabric covered welded chrome-moly steel structure.  The Vertical fin was ground adjustable, whereas the horizontal stab was adjustable in flight.  The landing gear was an air-oleo outrigger style which provide a very wide 110” stance.  The swiveling tail wheel was mounted on the very aft of the fuselage and a rudder cut-out was provide for fitting.  Fuel was carried in two wing root mounted 41 gallon tanks.  It had an inertial starter, metal prop, individual wheel brakes.  Berryloid finishes were used.

There were approval issues regarding the front wing spar strength.  It seems as though several early models (up through around serial number 1048) had light weight spars and were limited to the 165 hp engine.

SM-2A,  was originally designed as a 4 PCLM with a Challenger 170 hp engine, however the engine was never used and no models were produced.


SM-2AA,  4PCLM Type Certificate number 145, Issued 20 May 1929.

Group 2 Approval Number 2-73 was issued on 31 May 1929 for the first five airplanes.

First plane delivered Jun 1929.

Serial Numbers 1046 to 1126

Factory Location:    Wayne, MI

Number Built:          up to 80

Engine:                   Wright J6 (R-540), 5 cylinder, 175 hp engine. 

Weights:                 Empty: 1972 lbs, Useful: 1180 lbs, Gross: 3152  lbs

Cruise Speed:        97 mph

Fuel:                       60 gals

Oil:                          5 gals

Length:                    26 ‘  4”          Height:    7’  6”

Wing Span:             41’  6”           Chord:     75”

Airfoil:                     Clark Y                       

Factory Price:         $8500  (2018:   $122,540)

SM-2AB,  4PCLM Type Certificate number 1, Issued 11 June 1929.  Amended on 10 Sep 1930.

Serial Numbers 1047, 1053, 1055, 1056 to 1130

Factory Location:    Wayne, MI

Number Built:          up to 77

Engine:                   Wright J5,  9 cylinder, 220 hp engine. 

Weights:                 Empty: 2169 lbs, Useful: 1060 lbs, Gross: 3200 lbs

Cruise Speed:        112 mph

Fuel:                       70 gals

Oil:                          5 gals

Length:                   28 ‘  4”          Height:    8’  4”

Wing Span:             41’  6”           Chord:     75”

Airfoil:                     Clark Y                       

Factory Price:         $10500  (2018:   $148,245)


Fuselage was lengthened and faired differently to accommodate the larger engine horsepower.  The wing were essentially the same except that the spars where made from heavy spruce routed out to an “I” beam section.  Fuel capacity was increased for the larger engine and the landing gear was strengthened as well as lengthened.  Wheel base remained at 110” although the main wheels were either 30 x 5 or 32 x 6.



SM-2AC,  4PCLM Type Certificate number 194, Issued Aug 1929.  Amended in November of 1929 to include the

SM-2ACS (float plane with Fairchild P-2 floats) version


Factory Location:    Wayne, MI

Number Built:          up to 76, unknown how many 2ACS were built

Engine:                   Wright J6 (R-540), 7 cylinder, 225 hp engine. 


Land:                      Empty: 2091 lbs, Useful: 1126 lbs, Gross: 3217 lbs

Sea:                        Empty: 2396 lbs, Useful: 1126 lbs, Gross: 3522 lbs

Cruise - Land:        113 mph

Cruise – Sea:         100 mph

Fuel:                       70 gals

Oil:                          6 gals

Length:                   28 ‘  6”          Height:    8’  4”

Wing Span:             41’  6”           Chord:     75”

Airfoil:                     Clark Y  


Factory Price (Land):         $11,000  (2018:  $155,300)

                       (Sea):          $13,000  (2018:  $185,250)


A skylight was added in the cabin ceiling, and the engine was muffled by a large collector ring that was mounted on the front of the engine. The wing struts were changed and were chrome-molly steel tubing formed to a Eiffel 380 airfoil by balsa wood fairings.

SM-2K Special,  4 PCLM with a Kinner B, 125 hp engine, and a 3 PCLM  with a Kinner K, 100 hp engine.

Group 2 Approval Number 2-90.  Kinner K-5, 90 hp engine was approved under Group 2-136.

Factory Location:      Wayne, MI

Number Built:            Three planes were eligible, s/n 1029,1033, and 1037

Engine:                      Kinner B - 125 hp, Kinner K - 100 hp, Kinner K-5 at 90 hp

Fuel:                          47 gals

Oil:                            3.5 gals

Weights:                    Empty: 1641 lbs,  Useful: 859 lbs, Gross: 2500 lbs

Cruise:                      105 mph

Length:                      26'  7"                      Height:         8'   4"

Wing Span:               41'  5"                      Chord:          75"

Airfoil:                        Clark Y

In a 29 August 1929 letter from Stinson to the Department of Commerce, Aeronautics Branch it states “ I wish to state that the SM-2A is a basic label referring to all models of the SM-2A type, having different motor installations.  The SM-2A type is a continuance of our last year’s SM-2 so that a great

many of the drawings are the same.  We have, however, added the SM-2A to the original SM-2 drawings.  The status of our SM-2 types is as follows:


SM-2                4 PCLM            Warner 110 HP             Obsolete Model

SM-2A              “      “                Challenger 170 HP        Engine not used –  no models in existence

SM-2AA           “       “               Wright 165 HP R-540     Standard Model

SM-2AB           “       “               Wright 220 HP J-5         Standard Model

SM-2AC           “       “               Wright 225 HP R-760    Standard Model

SM-2AD           “       “               Lycoming 185 HP          Special Installation

SM-2AE           “       “               Continental 165 HP       Special Installation

SM-2K              “       “               Kinner B-5  125 HP       Special Installation


Where the A, B, or C letter is used after the basis label refers specifically to that particular motor installation.”


The letter was signed by Kenneth M. Ronan, Chief Engineer, Stinson Aircraft.

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