A.T.C. #685 (6-22-38) STINSON "RELIANT", SR-10F

The big and bold Stinson "Reliant" model SR-10F was perhaps the absolute pinnacle of achievement in this long-running series of airplanes, and as Stinson put it, "This is no doubt our last and our very best." Stinson had a prolific line of models to choose from in this last series of "Reliant" airplanes, but the SR-10F, as powered with the 450 h.p. "Wasp Jr." engine had special appeal to the moneyed customers. Be they private, corporate, or governmental, they were willing to pay well to enjoy all the extras their money could buy. Of certain models in years previous Stinson Aircraft had said "This is the greatest airplane we have ever built." but that was then, and now they would have to say it again! There's no doubt about it, the SR-10F was truly a superb airplane; it had good looks, it had "class." it had unusual ability and altogether it was a special kind of airplane. The circle of owners was fairly small, but were a proud group and they never failed to exhibit that pride in their choice wherever they went. The fancied-up SR-10F, because of its characteristics, was used mostly as a "limousine" for private-owner transport, but an airplane with so much ability was bound to be considered as a working airplane where its talents would also be of great value. At least one of the SR-10F went to Alaska to work "In the bush," and the U.S. Dept. of Agriculture used their SR-10F for urgent jobs not many other airplanes could do as well. Routinely it would drop in supplies to inaccessible firefighters, and occasionally to a stranded prospector, or a trapper; it was able in all emergencies and no job was apparently too difficult. During the early part of World War II some 8 of the SR-10F were impressed in USAAF service as the UC-81F; there was also one experimental model (XC-81D) to be used in testing procedures of glider pick-up. Of course, most of the SR-10F survived the war period and served on faithfully in many capacities for years to come.

The Stinson "Reliant" model SR-10F was a big looking, high-winged cabin monoplane with seating arranged for 5 in ample comfort. This airplane was truly elegant, very plush in the expensive "Deluxe" version, and usually adorned with all the extras that one could possibly buy for an airplane of this type. As generally used in the pursuit of business matters, as an executive transport, or the exploiter of a product, the very capable SR-10F offered speed and utility with an intimate type comfort. Like some of the other "Reliant" before it this was an impressive airplane, and it had the knack of making its presence felt; this was good for business. The SR-10F was rather big and heavy, but the massive wing created plenty of lift, and this translated into surprising short-field performance with a sizeable payload. It is logical too that the SR-10F, with all its muscle and ability, would be offered as a multi-purpose airplane (SR-10FM) for freight, charter, or what-have-you. In this version the interior was metal-clad and larger doors allowed the loading of boxes, bundles, barrels, or whatever. This airplane was also available as a seaplane on Edo twin-float gear. The "Reliant" was an airplane with a many-faceted personality-it could put-on-the-dog with the best of them, but it really didn't mind getting its face and hands dirty, either. As powered with the 9 cyl. "Wasp Jr." SB or TB engine of 400-450 h.p. the SR-10F was a lively brute that reveled noisily in its unusual abilities and its high performance. It got off the ground very quickly, had a terrific climb-out, and when leveled off in proper trim it was also hard to catch. Pilots have said that with' all this power surging through its frame it was inclined to be a brute at times, but it was inherently amiable and responded well to firm handling. The type certificate for the model SR-10F was issued 6-22-38 and some 18 examples of this model were manufactured by the Stinson Aircraft Corp. at Wayne, Mich. The factory airport was a dinky little field, and Stinson often pointed out that if an airplane could operate out of here, it could operate just about anywhere. W. H. Beal was now pres.; Wm. A. Mara was V.P. in charge of sales; Lew Reisner was gen. mgr.; and R. W. Middlewood was chf. engr. We note in passing that responsibilities of the former Bureau of Air Commerce (BAG) were taken over by the new Civil Aeronautics Authority (CAA) on 23 June of 1938.

Listed below are specifications and performance data for the "Reliant" model SR-10F as powered with "Wasp Jr." SB engine rated 400 h.p. at 2200 r.p.m. at 5000 ft. (450 h.p. at 2300 r.p.m. for takeoff); length overall 27'11"; height overall 8'7"; wingspan 41'11"; max. wing chord 96"; total wing area 258.5 sq. ft.; airfoil Mod. Clark Y; wt. empty 3045 lbs.; useful load 1605 lbs.; payload with 60 gal, fuel 1026 lbs.; payload with 100 gal. fuel 786 lbs. (4 pass. & 106 lbs. baggage); gross wt. 4650 lbs.; max. speed 170 at sea level; cruising speed (.75 power) 177 at 9600 ft.; landing speed (with flaps) 63; climb 1330 ft. first min. at sea level; ser. ceiling 21,000 ft., gas cap, normal 100 gal.; gas cap, max. 124 gal.; oil cap. 6.5-8 gal.; cruising range (.75 power at 9600 ft.) using 25 gal. per hour was 680-850 miles; price not announced because of the variables in the way it was equipped. Also available with "Wasp Jr." TB engine of 420-440 h.p., or the SB2 or SB3 series.

The construction details and general arrangement of the model SR-10F were quite typical to that of the previous SR-9F except for the following modifications and improvements. The fuselage framework was also beefed up in places to handle the stresses of 450 h.p.; the windshield was now again built up of flat panels because the panoramic "formed" windshield had proven somewhat unsatisfactory during production and it presented some areas of distortion. The engine's exhaust system was improved, and the entire engine cowling with improved baffling, was redesigned for better cooling and less drag. The spacious, plush cabin was an eye-opener, and the soft rear seat accommodated 3 across with surprising comfort. Baggage allowance was 150 lbs. with 50 lbs. of it under the rear seat, and 100 lbs. in the compartment behind the rear seat; a hat shelf was also provided. The big, unusual wing was pretty much the same, but there was improvement in some detail. Three fuel tanks (38-38-24 gal.) in the wing comprised the normal fuel supply, but an extra 24 gal, tank was available for a total of 124 gal. Because of high operating weights the 7.50x10 wheels were fitted with (6-ply) 8.50x10 tires; streamlined metal wheel pants were optional. The "multi-purpose" (SR-10FM) equipment included a metal-lined cabin interior, extra door, and cargo tie-downs; the baggage compartment was eliminated to lengthen floor space. The SR-10F and SR-10FM were also eligible as seaplanes on Edo 59-5250 twin-float gear at 5200 lbs. gross wt. In the later "5900 series" the SR-10F was more or less the same, but differed slightly in the fuel system, battery locations, engine exhaust system, engine cowling, pilot's seat, the control wheels, and vertical tail surfaces. A controllable "constant-speed" prop, electric engine starter, generator, battery, oil cooler, carburetor heat-box, wheel brakes, parking brake, dual controls, cabin vents & heater, roll-down windows, fire extinguisher, navigation lights, clock, compass, map pockets, 10 in. tail wheel, bonding & shielding, safety belts, assist ropes, and first-aid kit were standard equipment. An extra battery, extra fuel tank, extra instruments, radio gear, multi-purpose equipment, wheel pants, cactus-proof tires, pressure-type fire extinguisher, freight pickup equipment, landing lights, fog lights, para-flares, parachute-type seats, vacuum pump, corrosive protection for seaplane, and a 16-coat hand rubbed finish in custom colors was optional. The next Stinson development was the little "Model 10" as described in the chapter for ATC # 709.

Listed below are SR-10F entries as gleaned from registration records:

NC-18479; SR-10F (# 7-5815) WaspJr.400.

-18494; SR-10F (# 7-5826)

-18495; SR-10F (# 7-5832)

-21108; SR-10F (# 7-5833)

-21112; SR-10F (# 7-5834)

NC-2428; SR-10F (# 7-5835)

-21116; SR-10F (# 7-5836)

NC-2429; SR-10F (# 7-5837)

NC-2166; SR-10FM (# 7-5845)

-21111; SR-10FM (# )

NC-2311; SR-10F (# 5910)

Ser. # 7-5815 del. to Gulf Oil Co. in Pa.; two SR10F del. to Texas, 2 del. to Florida, and one each to No. Dakota, Illinois, New Jersey, Oregon, and Delaware; NC-21111 (ser. no. unknown) was del. to Alaska; there is record that 18 of the SR-10F were built, but no complete listing was available; this approval expired 2-28-41.

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Last modified: March 23, 2004