The majority of U.S. pilots of World War 2 received their primary flight training in the famous Stearman Trainer. This excellent 2-place biplane was known as the PT-17 when delivered to Army flight training centers.  The Navy designations were N2S-1 and N2S-4.  Nearly 3000 were built in the 1940-43 period.  In the post war era and up to modern times, the Stearman Trainer has been used as a stunt plane and crop duster.

This 1/16 scale model is built from a Guillow's kit originally designed for rubber power or .049 to .15 U-Control or free-flight.  I have converted this one to 4 Channel radio control and electric propulsion.

I built this kit from the start with the electric power RC conversion intended.  Guillow's kits are infamous for their unpredictable and often poor quality balsa wood they come supplied with and attrocious die-cutting.  I got lucky with this one as they must have recently sharpened the dies as most of the cuts were clean and the parts needed little additional cutting to free them from their sheets after a thorough sanding of the back-sides.

The balsa quality was also reasonably good so I was able to use most of the supplied parts, except where I made changes to accomodate the RC gear and add strength for the greater stress it will be subjected to.

The model is covered with the silkspan from the kit and finished in Cub-Yellow and Corsair-Blue Aero Gloss dope.

9/16/00 Update: The Stearman has flown for the second time today. This time more of the bugs were worked out. It now runs on a Permax 280BB motor and is spinning a Grish Tornado 7x6 prop. The 8x6 was producing too much torque roll and consumed too much power shortening flight times too much.  First flight revealed the need to add down and right thrust which has been accomplished. Heavier balloon tires were added to bring the CG more forward.  The second flight was much more controllable and just a little down elevator trim was required. I think it may still be a little tail heavy but its flyable now.  The power from the 280BB is fine and 1/2 throttle flight still gives reasonable performance.  The flight was ended after about 3-4 minutes due to uncertainty of battery run time.  I need to build another battery pack or two then this plane is going to get plenty of flying time!

9/02/02 Update: I just changed the power system in my Guillow's PT-17 Stearman and it finally flies very nicely. I struggled several times with it using a geared sp300 and 8x720mAH NiMH. There was more than adequate power but it was tail heavy and almost unflyable. Adding dead weight to achieve proper CG caused it to become too heavy for the available power and it would not climb.

After looking at the PT-17 hanging from the ceiling for two years last week I finally ripped out the 300 motor, gearbox, and it's mounting, and removed all the lead in the nose and the heavy wheels.  I replaced the wheels with lightweight foam ones, and installed a direct drive speed400 mounted to a simple dowel and rubber band mount. I retained the same 8 cell 720 NiMH pack. It's turning a Graupner 6.5x4 prop. The plane actually came out lighter even though the motor was slightly  heavier. All-up weight is now 14.5oz.

This totally transformed the plane. It now will ROG, loops, is quite stable, and lands nicely. It is well behaved and gets a good solid 6-8 minute flights. I even tried 7x720 NiMH cells and it flies adequately.
 

Here's some of the specifications for my model

Scale	1/16
Wing Span	28"
Wing area	~ 225 sq. in.
Weight - Airframe & RC gear only	8.4 oz.
Weight - Ready to fly (including pilot figure)	UPDATE: 14.5 oz.
Motor	Update: Graupner Speed 400 7.2V
Gearbox ratio	3.66:1
Propeller	UPDATE:  The Graupner 6.5 x 4 used in photos
Battery	8-AAA cell 720mAh NiMH  Sanyo
Controls	Ailerons, Elevator, Motor, Rudder
Servos	3 x Cirrus CS-10 BB "Molecular Micro"
Electronic Speed Controller	FMA Mini 20
Receiver	GWS Pico 4channel

This was the original version below. Click on any picture to see a larger version and find out details about it.

A few new Pictures:

(Added: 27-Aug-2000)
Download my Stearman model for FLYRC flight simulator:  stearman.zip
Where to get free FLYRC flight simulator: http://www.pivot.net/~acarr/ron/ron.htm

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