Convert your Stinson 108 series aircraft to…

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The "Stinson 220"™ FRANKLIN conversion offers a First-Class solution when considering upgrading the powerplant in your Stinson. STC approved upgrade kits are now available from Franklin Aircraft Engines, Inc. to install an astonishing 220 horsepower in your Stinson 108-1, 108-2 or 108-3 aircraft.

Here's the extra boost your Stinson needs to make a solid airplane even better. The spectacular Performance will make your Stinson more fun to fly, provide greater 4-place utility and increase the re-sale value of your Stinson.

The combination of increased horsepower and a Constant Speed Propeller means impressive top speed, unbelievable take-off and remarkable rate of climb.

Just as important, the 220 FRANKLIN engine delivers 6 cylinder, low r.p.m. smoothness much like the lower h.p. Franklin engines are famous for! In addition, the conversion includes the installation of a high amperage alternator and a vacuum pump may be installed as an option with no special drive requirements.

The "Stinson 220" FRANKLIN conversion consists of changing out the engine, propeller, engine mount, exhaust system, oil cooler, ducting and cooling baffles. A manifold pressure gauge and propeller control cable is added to the panel. Some Stinson models may require battery relocation, fuel line upgrade, or a rudder trim bungee kit. In addition, some engine controls and monitoring instruments may need changed out to match the operating limits of the new powerplant.

The intake and exhaust systems have been engineered on the basis of dynamometer tests to produce maximum h.p. at the propeller. Exhaust systems feature dual high output heaters. One provides cabin comfort at coldest temperatures; the other is for carburetor deicing under adverse weather conditions.

Low level engine vibration permits extremely compact, near-solid engine mounting and close fitting cowling. Only minor cowling modifications are required to install the FRANKLIN 220. Other engine conversions may require major rework of the cowling to provide adequate engine clearance.

The FRANKLIN powerplant is one of the most durable certified aircraft engines flying today. The 220 h.p. FRANKLIN is essentially the same power section as the famous 335 c.i. FRANKLIN used in Bell and Hiller helicopters. These were designed to operate at a continuous full throttle 3200 r.p.m. and turbocharged to 41" M.P. to produce 260 h.p! The FRANKLIN 220 develops maximum h.p. at only 2800 r.p.m.



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On your first flight, your "Stinson 108" will reveal that it is All Business…

Truly a spectacular 4-place performer on land or sea.

"Why settle for less Horsepower !"

(Performance chart based on Aircraft at gross weight)

Franklin 6A-350-C
220 HP
Max. Level Speed
(at 7000') (MPH)
Max. Cruise Speed
(at 7000') (MPH)
Max. Rate of Climb
(Sea Level) (Ft./Min)
Service Ceiling
Take-of Run
Stinson 108-1, 2&3 Land 160--- 151--- 1,600 18,000 300--- 600

*Max Gross Weight of 2499 lbs. for 172D-P for operation on wheels or floats.



Considering Floats for your Stinson ? No Problem !

Franklin Aircraft Engines, Inc. can provide you with STC approved paperwork to install Floats on some Stinson models with a gross weight increase as an added bonus !


The overall cost of the conversion can range from the low $20's to the mid $30's. The low end can be achieved by locating a mid-time or overhauled engine, propeller and accessories. If you choose to install all new components, you will reach the high end of the expense range. Keep in mind, when you convert to the FRANKLIN 220, you have your old firewall forward package to sell and can apply that sale towards purchasing your ultimate upgrade.

As a comparison to overhauling your existing engine, you may spend $13K to $15K to rebuild your existing 150 or 165 h.p. Franklin. Even after the engine overhaul expense, you may spend more money in repairing or rebuilding your old propeller, exhaust system, engine mount, cooling baffles, oil cooler, carburetor heat box, accessories, oil/fuel hoses, etc…

Even after all the expense of overhauling your existing powerplant, you won't see much of a gain in performance and will only increase the re-sale of your airplane by about 10%. In comparison, many Stinson owners claim over a 50% increase in their airplane re-sale value after converting to the "Stinson 220".

The basic STC approved installation kit is available directly from Franklin Aircraft Engines, Inc. which includes the STC Paperwork and Installation Instructions, a new engine mount, new exhaust system, new carburetor heat box, new oil cooler, new brackets and other miscellaneous items. The goal here is to provide the installer with components that require special fabrication procedures, inspection processes and manufacturing equipment. Other items such as oil hoses, scat hose,clamps, etc… are readily available from many different suppliers.

If you are considering upgrading the powerplant in your Stinson… the "Stinson 220" FRANKLIN upgrade will offer you a first class solution, provide unmatched performance and all at a sensible cost.

"Power by FRANKLIN"™
"Performance by FRANKLIN"™
"FRANKLIN 220" ™
"220 FRANKLIN" ™
"Stinson 220" ™
"FRANKLIN Power" ™
"FRANKLIN Upgrade" ™
"FRANKLIN Conversion" ™
"FRANKLIN Powerplant" ™

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