Boeing Super Stearman

Classic Biplane Model from Great Planes

Table of Contents [Toc]

Specifications
The Final Plane
Flight
Construction
Modifications
Transportation

Specifications [Toc] [Top]

Manufacturer:	Great Planes, Champaign IL, USA
Wingspan:	181.5 cm top / 175.5 cm bottom wing, wing depth: 28.3 cm (top & bottom wing)
Length:	145 cm
Weight:	approx. 6.8 kg
C.G.	140 mm +/- 9 mm (top wing)
Engine:	O.S. FS-120S III-P four-stroke engine with pump system, 45 degrees hanging
Propeller:	TopFlite 18x6" Power Point Propeller (Wood) Xoar International 18x6" PJA Series Beechwood Propeller (Wood) Master Airscrew 18x6" Classic Nylon (Composite) After trying a few different propellers, I currently prefer wood propellers from TopFlite or Xoar International on my Super Stearman, since these propellers are superior in performance compared to the composite variant from Master Airscrew.
Controls:	Engine, Elevator, Ailerons, Rudder using 4x Hitec HS-645MG high-torque metal-gear servos for control surfaces and 1x Hitec HS-485HB servo for throttle
Description:	High-quality classic biplane ARF model from Great Planes, which is completely covered in Monokote. Both, top and bottom wing feature individual ailerons for increased agility. The two wings are mounted with 2 nylon bolts and 12 metal bolts. The kit already includes two pilots and the exceptional aluminum spinner. After completing the aircraft, I was quite surprised by requiring only 60 grams of lead in order to attain correct center of gravity (C.G.). During maiden flight, I only had to slightly trim down the plane by about 3 trim units and to add a few trim ticks of right rudder and aileron. Using a 1.20 four-stroke engine, the Great Planes Super Stearman 120 flies as gentle as a classic biplane, sounds as sonorous as a lion, and rolls as graceful as a whale. In my opinion, the 1.20 four-stroke engine constitutes the lower end of the engine range, but it absolutely satisfies the needs for scale flying including light aerobatics. I recently changed to using wood propellers on my Super Stearman, since these propellers deliver superior performance compared to composite variants. However, I found myself considering the O.S. FS-200S-P as possible engine upgrade for more substantial aerobatics, as, compared to the FS-120S III-P, the FS-200S-P has similar weight, identical mounting footprint, and only 1 mm increased distance to the drive washer. When time comes by and I need more thrill with my Super Stearman, I'll probably check out the O.S. FS-200S-P... Resources: Manual, Product website, Review 1, Review 2
Modifications:	i) Replaced the supplied nylon control horns for elevator and aileron with stronger and more durable control horns. See picture below for clarity. ii) Installed elevator and rudder metal-gear servos to the front, throttle servo to the back of the servo tray. See picture below for clarity. iii) Replaced the supplied light-weight plastic wheels with low-bounce Dubro 4" unthreaded inflatable rubber wheels. See picture below for clarity. iv) Mounted the engine 45 degrees hanging in order to get muffler protruding vertically between the gear legs. See picture below for clarity. v) Installed O.S. remote glow extension for convenient engine start procedure. See picture below for clarity. vi) Rotated lower aileron nylon control horns connecting the lower and upper wing ailerons using connecting rods in order to get increased swing of lower ailerons without getting limited by the top ailerons. See picture below for clarity. vii) Installed all aluminum push-rod tubes of the dummy radial engine to preserve the visual nature of the 9 cylinder radial engine. See picture below for clarity.

The Final Plane [Toc] [Top]

The completed Great Planes Super Stearman 120* ready for maiden flight.*	Left side view of the Super Stearman.
I selected the two-servo aileron configuration with connecting rods between top and bottom ailerons.	Right side view of the Super Stearman.
The supplied nicely painted wheel pants and engine cowl add to the unique overall appearance of the Great Planes Super Stearman.	Enjoy the very nice 9 cylinder dummy radial engine with polished aluminum push-rod tubes and the elegant aluminum spinner, all included in the kit.
Front view showing the small dihedral of the bottom wing and the flat top wing.	The O.S. FS-120S III-P swinging the Master Airscrew 18x6" at idle throttle.
Taxiing on the runway at idle throttle.	Close view at the Super Stearman's engine section at idle throttle.
There is sufficient ground clearance for the large 18x6" propeller.	By using all supplied aluminum push-rod tubes and by only applying a cut-out to the plastic part of the dummy radial engine, I successfully preserved the perfect overall appearance of the radial engine inside the cowl.
Take-off during maiden flight at September 20th, 2010.
Final pictures after successful maiden flight of my Super Stearman...	Sun reflections on the beautiful airborne classic biplane.
Well, the classic biplane flies as gentle as it looks...
A table provides valuable support for assembling/disassembling the biplane.	The Great Planes Super Stearman stands proudly on the table in the evening sun.
The engine section of the Super Stearman with its impressive aluminum spinner.

Flight [Toc] [Top]

A collection of nice in-flight pictures of my Great Planes Super Stearman 120. Many thanks to André R. for taking these pictures and sharing them! Being the pilot at duty, I cannot take myself in-flight pictures of my model airplanes...

The Super Stearman flies really beautiful and the sound from the four-stroke engine is amazing - please refrain from installing any electric power solutions in this graceful classic biplane, it is a sin!

The airborne Great Planes Super Stearman 120 - a beautiful classic biplane!	An amazing visual impression accompanied by realistic four-stroke engine sound.
Low-level fly by for the photographer.	Super Stearman with the 'Uetliberg' in the background of the scene.
Well, it was a little bit windy at that day...	Increasing the throttle a bit will help in keeping a safe airspeed.
Nice picture of the Super Stearman flying above the crops.	Continuing the fly by with a little climb...
A little climb to get a safe ground margin.	Close fly by.
Great in-flight picture!	Some more in-flight pictures...


The Super Stearman during final approach for landing - ready for a perfect bounce-free three-point landing...	Ups, direct impact of turbulence (from left side). Note that I don't use any electronic assistance systems for stabilizing airplanes.
Quickly realigning the plane in order to be prepared for ground contact...	Magnification of the picture at left: Just milliseconds before the plane touches ground.
Safely landed and stopped. Yes, it is a fuel-powered four-stroke 20cc glow engine.	And finally taxiing back.
Well, with the Super Stearman, take-off is usually more demanding than landing. The picture shows the final position after an unsuccessful take-off attempt: Although only employing reduced throttle during take-off and trying to control the rudder, the plane has gone wild, ending in this position with a wheel collar being loose. Whether the wheel collar came off during take-off or during the wild ride remains unclear, however, the effect of a loose wheel collar is clearly illustrated by this picture...

Construction [Toc] [Top]

Some impressions of the construction work of the Great Planes Super Stearman 120.

The Great Planes Super Stearman comes in a perfectly packed box.	I mounted the O.S. FS-120S III-P engine 45 degrees hanging in order to allow the muffler to protrude vertically between the legs of the landing gear.
The muffler fits nicely into the overall cowling structure. I cut openings into the cowl for engine rocker cover and muffler.	The engine and the weight box inside the cowl.
I installed the O.S. remote glow extension for convenient engine start procedure.	The completed engine installation with fuel filter, O.S. remote glow extension, and weight box.
I installed all aluminum push-rod tubes of the dummy radial engine to preserve the visual nature of the 9 cylinder radial engine.	The dummy radial engine painted in flat black really looks very appealing...
Cutting the two openings in the cowl for engine rocker cover and muffler.	The finalized cowl integrating nicely the engine rocker cover and the muffler.
Graceful light reflections on aluminum spinner and 9 cylinder radial engine compartment.	The O.S. FS-120S III-P effectively disguised behind the dummy radial engine.
The cut-out for air cooling of the O.S. FS-120S III-P four-stroke engine.	R/C equipment with high-torque metal-gear servos for elevator and rudder.

Modifications [Toc] [Top]

I made a few modifications to the original model plane, as stated on top. Some of them are illustrated here.

Replaced the supplied nylon control horns for the elevator control surfaces with stronger and more durable control horns.	Replaced the supplied nylon control horns for the aileron control surfaces as well with stronger and more durable control horns.
I first mounted the nylon control horns of the aileron connecting rods according to the instruction manual. However, I was unsatisfied with the throws of the lower ailerons, ultimately limited by the throws of the upper ailerons and the differential created by the connecting rods. Consequently, I rotated the lower nylon control horns by 180 degrees in order to reduce the throws of the lower ailerons onto the connecting rods. Hence, I achieved a larger throw of the lower ailerons without being limited by the upper ailerons by effectively reducing the differential between the control surfaces.	Installed low-bounce Dubro 4" unthreaded inflatable rubber wheels, which add another 140 grams weight compared to the supplied light-weight plastic wheels. However, I don't think the additional weight noticeably influences the flight characteristics.
Illustrates the mounting of the aileron connection rods. I use the holes being nearest to the control surface at both ends.	The picture illustrates the dimensions of the aileron connection rods. The measured distance between the clevis pins of my aileron connection rods are 295 mm and 296 mm. As depicted on the picture, I could not use locking nuts at both ends of the connection rods, therefore I applied thread lock compound to secure the clevis. Moreover, I use the supplied small control horns with the hole being nearest to the aileron control surface.

Transportation [Toc] [Top]

Well, the Great Planes Super Stearman 120 even fits into a VW Golf III - so there might be no excuse for not building this plane because of issues concerning car transportation...

Super Stearman 120 in the trunk compartment of my Volkswagen, with the wing bag on top.	I only had to craft a specifically adapted Styropor plate for the trunk of my VW Golf III.
Well, it looks like the Super Stearman has been designed with a VW Golf as minimum transportation vehicle in mind...

As of September 2011, I've upgraded my 19 years old but pretty reliable Volkswagen Golf III to a new Škoda Superb II Elegance 2.0 TDI-CR 4x4 DSG...

Škoda Superb II Elegance 2.0 TDI-CR 4x4 DSG

Eventually better suited to transport model air planes...

Last updated: 2012/04/08

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