|Wing Area:||1,466 sq. in.|
|Wing Loading:||22-23.5 oz/sq. ft.|
|Wing Area:||1540 sq. in.|
|Weight:||14 lb. 5 oz.|
|Wing Loading:||21,4 oz/sq. ft.|
|Engine:||OS FS120 Surpass|
|Prop:||APC 18x6 wide|
|Spinner:||Tru Turn AT6 Spinner Hub(optional replacement; kit includes an alum. spinner)|
|Battery:||5-cell 1500mah NiCD battery|
|Available From:||Tower Hobbies|
“One of the best known two-place, open cockpit biplanes of World War II was the Stearman PT-17 Kaydet primary trainer. Many Army Air Corps student pilots flew for the first time at the controls of a Kaydet, learning the basics of flight before passing on to the larger and heavier BT basic and AT advanced trainers.”
“Over 10,000 Model 70-76 series aircraft were built between 1933 and 1945. These aircraft served the Navy, Army, and many other air arms during WWII and post war as primary trainers. The major production version, the Model 75 was built as PT-13, PT-17, PT-18, and PT-27 for the Army and as the N2S for the Navy. Post war over 4000 Stearman biplanes were re- engined with 450 hp. Pratt & Whitney R-985 Wasp radials and converted for agricultural dusting/ spraying. While technically built by Boeing's Wichita Division, these rugged trainers are universally known as Stearmans. Many still fly today as prized antiques.” (Quote courtesy of Aviation Enthusiast Corner)
Great Planes Model Manufacturing Co. Inc. has recently made it possible for all of us who are eager to fly a radial-engined biplane by producing an Almost Ready to Fly version of one of these “Super Stearman” versions, and I’ll be starting construction as soon as I open the box.
...PLUS...STOCK IN EVERY KIT...
Additional Items Needed for Completion:
All the major sub-assemblies are packaged in clear plastic bags, with lots of clear tape holding them in place. My plastic windscreen assemblies arrived intact. It takes almost as long to remove the packing materials as it does to assemble the kit!
I ran an inventory of the parts in the box against the parts list and found that the small jig blocks used to set dihedral were included, but not listed. Everything else on the list was in the box. (Interested in viewing the manual while you're waiting for your ordered kit to arrive? Just go to the Great Planes manuals page and download it!)
The fuselage and wing panels are all balsa and plywood construction, with cap strips on the wing ribs. The wheel pants, landing gear fairings, I-struts and cowl are fiberglass, and a mock radial is included (nice touch!)
There are quite a few seams in the covering, made by the multiple sections of MonoKote used to cover the Stearman. For example, the red covering on the leading edges of the wing is made from several sections, rather than cutting it from a single piece. There are no less than 10 pieces of covering on the fuselage, which I feel is excessive. Were I to cover the model myself, I could do it in three pieces if waste was not a problem. Several of the covering seams were “upside down”, meaning that a piece of covering was added to the top of the fuselage, and then a piece added to the lower part, making the overlap subject to coming unglued when cleaning or from engine exhaust.
I also noticed that there is a black pin stripe on the top and bottom of the top wing, and the top of the bottom wing, but none on the bottom of the bottom wing. Since the factory pin stripe pulled loose at several locations, I replaced it all with some 3M automotive striping tape, available at your local auto parts store.
The Top Flite Monokote covering is pretty well applied, but I ran a covering iron and heat gun over everything to bring out the bubbles, which appeared out of nowhere. (The extreme temperatures seen when a kit ships can be VERY hard on the factory covering job!) Be very careful near the covering seams, since the covering can be pulled loose with the application of excess heat.
The covering on the ailerons, elevators and fin/rudder all needed to be shrunk, but before applying heat, I poked some pin holes into each air-tight sealed bay inside the structure. This allows heated air to escape, rather than balloon out the covering. Heat the side of the structure without the holes first, since the heat will shrink the pin holes closed, and you’re back where you started.
I used Pacer brand epoxy products and ZAP instant adhesives to assemble the Super Stearman. Please provide adequate ventilation when using these or any adhesive products, and be especially careful when cutting, trimming or sanding fiberglass parts, as found in this kit.
First on the list was to hinge all 4 ailerons to the wing panels using the supplied CA type hinges. I found that all of the hinge slots on the aileron trailing edge were cut off center, allowing the ailerons to be located incorrectly when placed on the wing. I re-cut all the aileron hinge slots in the center of the aileron, and they fit perfectly.
The top wing has some dihedral so be sure to use the supplied balsa blocks to prop up the wing in the correct position. (Yes, they really do supply these blocks in the kit.) The lower wing has no dihedral and was assembled flat on the board, glued with 30 minute Pacer epoxy.
I chose to use the four aileron servo option, but at the time of initial assembly, the servos had not arrived. I always make up my own extension leads using #22 Teflon covered stranded wires that are soldered to the servo leads and twisted. This way, I can eliminate the use of any unnecessary connectors and the leads are made exactly the right length with no excess. I also use locking connectors with gold plated pins. Using a spare servo as a template, I made the pushrods and control horns. There is an option to use only 2 aileron servos with interconnecting links between the ailerons, and all parts and instructions are in the kit if you choose to go this route.
The main landing gear and belly pan were added and the holes cut for the tail pieces, using that hot soldering iron.
It was absolutely perfect as supplied in the kit, with no sanding or fitting required. Rather than use epoxy, which can get a bit messy, I used thin Zap to attach the stab to the fuselage, especially with such a wide gluing surface inside the fuselage. It will wick into the joint, but care must be taken to avoid dribbles caused by too much CA. (Don’t ask…)
The fin was added next, followed by the elevator halves, the rudder and tail wheel assembly. The tail wheel wire is loosely supported by the lower hinge, but mostly by the rudder.
The upper wing is held in place using bolted-on tabs that connect the interplane struts to the wing panel. The position of the fuselage cabane mounting screws was made by using the N struts to hold the wing in position and making sure the upper wing is parallel to the lower wing. The fuselage with the wings attached was placed on its nose and the two wings checked for relative location. The fuselage holes were drilled and the screws installed, making sure the screws go into the hardwood supports rather than the balsa fuselage sides. Mine fit quite well. Be sure to remove these screws and harden the screw threads in the wood with thin ZAP.
The interplane strut tabs were attached to the wing with Allen head bolts and the interplane struts were attached to the brackets with Phillips head bolts and safety nuts. I am planning to use longer Allen head bolts since the ½” long bolts supplied only engage 3 or 4 threads on the blind nuts in the wings. These will be removed and replaced when assembling or disassembling the plane, and a little extra length will be worthwhile.
My elapsed time so far, from opening the box to this point in the manual, is 3 hours. Your mileage may vary.
Great Planes included parts for a very handy carrying handle, to be assembled by the builder, to carry the fuselage along with the N struts to the field. It’s made from 20 pieces of plywood and a few small screws hold it in position on the plane. What will they think of next?
The throttle servo and pushrod were installed and I came to one of the harder parts of the assembly process, the installation of the cowl. There’s a plywood ring that was attached with bolts to tabs on the fuselage. The design made the bolts accessible from the rear of the cowl for easy removal. Using the engine for centering, the cowl was trimmed for cylinder head clearance and placed over the cowl ring. Once it is in place, it was tack-glued to the cowl, removed and fixed into final position using Pacer Fiber-Poxy. Holes for the muffler exit were cut in the cowl.
With the Hitec HS-475 ball bearing servos available at the work shop, I installed them in the upper and lower wing. The aileron push rods were cut to size and installed along with the plastic control horns. Extension cords were made up and pulled though the wing panels using the pieces of string that Great Planes thoughtfully added there when they initially assembled the wings. The servo wire exit holes on the top wing were near the center of the completed panel, making the location of the servo wire difficult to locate without being noticed. I relocated the exit hole near a cabane strut and will make arrangements to secure the wire during flight.
The fuel tank was assembled and installed inside the fuselage. I chose to add a third line with another clunk for filling and draining the tank. I also added an on-board glow plug lighter that will be controlled by a spare channel on my radio. I assembled a plywood box to be installed on the engine mount to hold the required lead needed to balance the Stearman. That’s correct; they actually provide a box to the 18 ounces of lead weight necessary to get the plane to balance. I’m hoping that my on-board glow lighter and battery will offset the need for so much lead. (Remember, the real model had a short nose and a VERY heavy engine. Our r/c equipment is so much lighter for the same power, that either the scale moments would have to be 'cheated', or noseweight is needed. Apparently, GP opted for noseweight.)
The wheels and wheel pants were installed, and it was good to see that the Stearman came with scale size wheels. All the holes and slots were cut and again it was good to see that the pants are of scale size, allowing the wheels to stick out quite a bit on the bottom, making for excellent ground handling.
The tail surface control linkages were made from solid wire push rods and plastic clevises. The split elevators were driven by a single servo, although builders may chose to use 2 elevator servos. In that case, one servo would have to be electrically reversed, due to the position of the push rod tubes in the fuselage. I would have liked to use a pull-lull rudder system, but it would be a hassle to install another push rod tube down the back of the fuselage.
Elapsed time to this point is just over 12 hours.
The receiver and battery were supposed to be installed on a removable plate just to the rear of the fuel tank area. This would get the weight near the nose, but I mounted the battery in the wooden box designed for the additional nose weight to have even more effect. Rather than use the lighter NiMH battery, I installed a 5 cell Nicad battery.
The charge jack and indicator LED for the on-board glow plug lighter and the radio switch and its charge jack were installed in the front cockpit, making sure it didn’t interfere with the position of the included pilot figures. I painted the cockpit interiors with flat black acrylic paint and used the included cockpit coaming to finish the edges. The fully painted and detailed pilot figures, let’s call one “Red” and the other one “Mister Blue”, were then added using a dab of silicone sealer. The plastic painted windshields were trimmed and attached using Pacer Canopy Glue. Some of the detail items like simulated panel lines with rivets and registration numbers were applied.
The Stearman kit came with a nice polished dome type spinner, similar to the ones used on the full size Super Stearmans, and I installed it using the supplied mounting kit. The spinner prop slots needed to be cut larger to allow the use of an APC 18-6 wide blade prop, and rather than mess up a perfectly good spinner, I ordered a new AT-6 style dome spinner from my friends at Tru-Turn. It was cut especially for this particular engine and prop combination and it was a simple bolt-on installation.
There was an optional flying wire “kit” that is simply a set of elastic cords that the user would have to purchase locally and install. I’ll leave those to the “rivet counters”. Great Planes also included some self stick plastic graphics to simulate rivets and markings found on the big Stearman. That’ll give those “rivet counters” something to count!
Elapsed time to this point is 16 hours.
There was not much left to do but set up the radio, check the balance and run the engine. The servos were centered, linkages adjusted and the Hitec Eclipse transmitter was set up to provide high and low rates plus exponential throws on all flight channels. I connected the on-board glow lighter circuit to the retract channel to allow me to turn it on and off at any time.
With the Stearman completely assembled, the radio battery and on-board glow lighter battery as far forward as possible, I marked the underside of the top wing at the place stated in the manual. I was totally shocked to find that the plane balanced perfectly without the addition of any additional nose weight at all. I attributed this to the fact that the original battery location was several inches behind the balance point, and I mounted my battery as far forward of the balance point as possible. I was also amazed to find that the Stearman weighed less than advertised, at 14 pounds, 5 ounces.
Note that you have several choices to find specifications and data on the Stearman: the instruction manual, the kit box and the on-line web site, which don't all quite agree. I placed all my faith in the measurements I found on the plane that I built, listed above, leaving the rest of the data for others to look at.
I had charged the on-board glow lighter battery and it was used to get the OS 120 Surpass running. A few minor adjustments with the high and low speed mixture needles were needed to allow the engine to run quite well. I ran a tank of fuel through it at mid-throttle to do a little break-in, and then advanced power to full to check high speed running. The OS 120 turned the big prop at almost 7200 RPM and idled at less than 1800 without the glow plug being powered. The fuel tank capacity was not listed, but I ran the engine for more than 45 minutes at part throttle and it finally ran out of fuel.
I loaded the Great Planes Super Stearman into my trailer, picked up my photographer, Jim Crawford, and headed to a place I refer to as “Area 51”, since it is isolated from just about everything. It took about 5 minutes to assemble the Stearman, and after a radio range check and filling the tank with some 15% glow fuel, I took the required ground photos for this review. I started the engine, adjusted it for a nice, slow idle, and cleared the carburetor with a high speed run. With my photographer in place, and nothing else to prevent me from doing otherwise, it was time to take to the air.
A slight breeze was blowing from right to left, and I pointed the Stearman’s nose into what little breeze there was. With a bit of power applied, it accelerated smoothly, with the tail lifting almost immediately. A bit more power and the plane lifted off the ground smoothly and steadily. It was climbing a bit more than I really wanted it to at this point, so a few clicks of down trim were added. Once a full circuit of the field was made, the Stearman was flying hands-off at half throttle. I increased power to full, but the engine seemed to be a little on the rich side, meaning this was all the speed I was going to have available at the present time. I took the Stearman to altitude, cut the power to idle and added full up elevator, which resulted in a dip of the nose and the resumption of straight and level flight. (The IDEAL stall!) A few loops and rolls were done, but the best maneuvers were the stall turns and the huge barrel rolls. This is how a Stearman is supposed to fly. I made several photo passes for the camera, and set up a landing. Power off, the Stearman just glided to the left end of the grass runway and with just a touch of up elevator, it settled down to a one bounce landing.
I checked everything and found that one of the swing keepers had popped loose from a top aileron. I must have loosened it when attaching one of the interplane struts, since they are close to one another. I just happened to have a spare in the parts box, and it was time to fly again.
The second take off was a little faster, since I had leaned the engine a bit. More low passes and mild aerobatics were done, including a sliding flat turn. The full scale Super Stearman, although powered by a 450 HP engine, was not an all-out aerobatic aircraft. Sure, it would loop and roll, but not like the aerobatics that are done by CAPs and Extras. Stearman aerobatics are slow and graceful, smooth and steady; just like the Great Planes Super Stearman is capable of doing.
The third flight of the day was even more enthusiastic, including an attempt at a knife edge and some inverted flights. Well one out of two isn’t bad. The Stearman would not hold a decent knife edge at all, just like a full size Stearman.
I decided to check the engine RPM, finding it was turning the prop at about 7200 RPM, fine for normal flight, but a little more speed might be necessary to perform some of the more enthusiastic maneuvers.
I didn’t have another prop with me that day, but I will do more testing. (Editor says: Look for follow-up to be added in the discussion thread for this article.) I plan to swap the 18 – 6 prop with a 16 – 8, which gives me almost 1400 more RPM and almost 15 MPH more calculated speed, according to “ThrustHP”, a PC program that calculates speed, HP and thrust, based on prop selection and RPM.
The bottom line for the Great Planes Super Stearman ARF is basically that is a terrific looking and equally terrific flying moderate size model. There are a few minor problems that can be corrected by the average modeler, but I wish the people who applied the covering had read the instruction sheet first. I’m still trying to get those wrinkles out. With the receiver battery up ahead of the firewall and an on-board glow lighter installed as far forward as possible, the Stearman balanced perfectly with no additional weight necessary. All this, plus it weighs less than they advertise and the wing area is larger than they state in the manual. This all makes for a great flying model.
There may be some of you out there who constantly feel the “need for speed”, and may wish to add a larger engine, maybe a gas/ignition type, to their Stearman. Something in the 25 to 35 CC size would probably do just fine, but watch the weight closely. Heavier planes only make larger holes in the ground.
To many glow and gas modelers, Dick Pettit needs no introduction, as he is a world-recognized scale builder. What you may not know is that his projects are both at lightning speed and with amazing detail and striving for perfection. This review is a little different than most on RCPower, in that Dick actually gives us the hours spent building this aircraft and yes...in most cases...they are straight through! Dick emailed me less than 24 hours after receiving the kit to show me how much progress he had made. To say I was surprised is an understatement! We thought you, the reader, would enjoy following the time line as well....
By all means.
I agreed to do only two categories of review planes here:
1- those that have already been reviewed by R/C REPORT, but not by me,
2- those that Gordon doesn't want reviewed, and AnnMarie does!
I'll still be "in print" for a long time.
More flying the Stearman
The more I fly it, the better it gets. I show up at a flying event, assemble the Stearman, and everyone wants a chance at the sticks. After they take their turn, they're heading to their local hobby dealer to order one.
The OS 120 is plenty of power for my style of flying, but I think a G-26 would also be a good power choice.
My choice of 4 aileron servos must have been the better choice, since I am hearing a lot of comments about the geometry problems when using 2 servos and the link rods.
I usually don't keep a particular model very long, since new ones always seem to be showing up at my door. But the Stearman will be around for a while longer than usual.
R/C REPORT Magazine
Engine Selection for stearman
I have just recently purchased a GP super stearman. I'm trying to decide between the G-26 and the Fuji 32. I know that the Fuji might be over powering the plane, but it's similar in weight to the G-26, so I was thinking that it might be a good thing to have the availability of the extra power. I would greatly appreciate any objective input on helping me make a choice.
I'm planning on purchasing a stearman and have a First Plane Engine 1.3 that I'm installing. It's 21 CC but they make a 40CC that is lighter than the G-26. The motors use an Electronic Ignition System that really cuts the weight of gas motors down. They also come stock with a pitts style muffler. Great little motors. Check them out and I think you'll be happy with them.
I got my 1.3 for $350.00
Thanks for the info Cannonball, but that is what I'm afraid of with the Cessna 182...It will fly like a real Cessna They just don't look right flying loops, hammerheads, and inverted flight
Back to the review...Great write up!
Hey Cad-- I also have the Stearman too. I have not flown it yet, but it's almost ready. It is powered with a Saito 180. I know, it's glow.. GP did a great ARF with this one. And it will look good doing hammerheads and loops and inverted..
See cannonball200 gallery for pics.
Last edited by cannonball200; Aug 11, 2004 at 11:11 AM.
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