Boeing-Stearman Kaydet PT13_17

Boeing-StearmanKaydet PT13/17US Airforce / Navy Primary Trainer

Assembly and finishing Manual

for ARF stand-off scale model

in 1:5 scale.

Historical data and presentation.

Model design and construction drawing by

Gran Kaldern

Rev. 2002-08-15

Stearman Kaydet PT17 ARF2


Boieng Stearman PT-17 KaydetNicknamed the Yellow Peril thanks to its

somewhat tricky ground handling characteristics, theStearman is one of the most easily recognized air-craft. Its simple construction, rugged dependability andnimble handling made the Stearman much loved bythose who flew and trained on it. The Stearman Kaydet,as it was officially named, was the only American air-craft used during World War II that was completelystandardized for both Army and Navy use as the PT13D (Army) and N255 (Navy). Sold by the thousandsafter World War II, the Stearman has had a long andfull career as a trainer, crop duster and air show per-former.

The famed Stearman Model 75 has its rootsin the earlier Model 70, which was chosen in 1934 asthe U.S. Navys primary trainer. At a time when bi-planes were becoming a thing of the past, the Model70 offered the fledgling pilot a steady and sturdy steed.Designed and built in only 60 days, the prototype Model70 could withstand load factors much higher than wereexpected to occur in normal flight training. The U.S.Army and Navy tested the prototype in 1934. At the

conclusion of these tests, the Navy ordered the air-craft while the Army decided to wait for the introduc-tion of the improved Model 75 appearing in 1936. Overthe next decade, the Armydecided to wait for the in-troduction of the improved Model 75 appearing in 1936.Over the next decade, the Army received nearly 8,500Stearmans in five different variants. The differenceamong these versions were the engines fitted; Kaydetswere fitted with Lycoming (PT 13), Continental (PT17) or Jacobs (PT 18) radial engines. The U.S. Navytook delivery of their first Stearman (called the NS-1 )in 1934. Powered with the obsolete but readily avail-able Wright R-790-8 engine, the NS-1 proved its worthas a primary trainer. The Navy purchased several thou-sand of an improved model, the N2S. The N2S wasbuilt in five sub variants, each variant being equippedwith a different model engine. Additionally, the Cana-dian armed forces took delivery of 300 PT 27s, a win-terized version of the PT 17.

A later, more powerful version of the Stearman,the Model 76, was purchased by Argentina, Brazil andthe Philippines.


Stearman PT-17 KaydetLength: 25' 7.62 MHeight: 9' 2" 2.79 MWingspan: 32' 2" 9.80 M

Wingarea: 297.00 Sq Ft 27.59 Sq MEmpty Weight: 1936.00 lbs 878.00 KgGross Weight: 2717.00 lbs 1232.00 KgPowerplant: Continental R-670-5, 220 hp


The ModelWe have chosen the scale of 1:5 rendering

a model size that i easy to fly but also relativelyeasy to transport. Both the upper and the lowerwing panels can be removed for transportationwhich gives very limited requirement fortransportation size. With a .1.20 4-stroke enginethe airplane is capable of most of the manoeuversin the book but still as docile as you can demandfrom a n advanced trainer.

The finished model is painted in 1939 liveryand further detailing can be made as perdocumentation.

Specifications:Wingspan cm 193Wingspan inches 77.2Length cm 149Length inches 59.6Weight grams 6600Weight Lb/oz 14lb. 8 oz.Wing surface dm 118 dmWing surface Sq.inch 1888 sqWing load g/dm 56 g/dmWing load oz/Sq 24 oz/sqEngine 2-cycle .60 - .90Engine 4-cycle .90 - 1.20C/G fr. Lead.edge upper wing 15cm / 6

Covering and finishThe model is covered and painted from the

factory. Where the original had aluminum coveringpanels, the model has the same. This also meansexcellent acces to the various compartments inthe fuselage when installing or servicing the radioequipment. When you have made changes in thefire wall and adapted the dummy engine to fit infront of the engine, you will have to cover the openareas with fuel proof paint.

Installation of engine.Our prototype was tried with an OS 1.20 FS

surcharge 4-stroke which gave more than amplethrust. The engine mounts have been installedfor this size of engine and in an upright positionfor several reasons.

The need for adequate cooling. The accessto the glow plug easily and finally to get thecarburator in line with the center of the tank.

1. Drill the holed for the engine in the "plywood ingine mount. Install blind nuts undersideof the plywood aligned with the holes

2. Drill the holes from the tank to thecarburator, pressure tap and the filling cap.

3. Install the engine and connect the throttleservo.No side or down thrust is deemed necessary. Youcan use an flexible exhaust manifold to lead theexhaust out under the center bottom panel to givea better apperance.

Installation of servos, tank, battery andreceiver.

The aileron servo is installed in the cockpitflooring. The elevator servo and the rudderservo are also installed in the cockpit flooring.

The trottle servo is installed behind theengine as well as the tank, booth on theengineboard.

Battery pack and receiver are positionedin the upper part of the tray.

The switch can be mounted on the frontcockpit instrument panel.

1. Attach a ball link head to joystick andrudder bar in the appropriate holes. You may haveto enlarge the holes to take the screw from theball link (Dubro #189 set of 2).

2. Install the servos for rudder and elevatorand temporarily connect the servo arms to theball links. Deflection for elevator is 20 up anddown and for rudder 30 right and left..

3. Install and connect the throttle servo inthe fashion you prefer.

4. Install the tank in the available space atthe right side next to the rudder and throttleservos..

5. Install the aileron servo in the bulkhead.The aileron connecting rods attaches to the servoarm. Deflection of the ailerons should be 20 upand down. The servo arm should be fashioned totake 2 clevices approx 1/8" apart.

6. Install the radio switch on the dash board.7. Place the receiver in the upper part of the

tray and the battery pack in front of the lowerfirewall, wrapped in foam rubber and secured withrubber bands.

Assembly of the PT17All parts have been assembled at the factory

and only disassembled for transportation.Rudder wires and elevator pushrod are

factory adjusted but may need some tensioningadjustment after a while. Aileron bellcranks arepermanently adjusted to the connecting rod.

Assembly of the tail unitSee detail drawing.1. Attach horizontal tail(3) to fuselage using 3 pcs4 mm nylon countersunk screws. Make sure thatstabilizer is flat against fuselage.2. connect the elevator control rod to the elevatorhorn.3. Insert vertical fin and secure to tailpost bracketand front of stabilizer. Attach rudder on to the finwith hinge pins.4. Secure the assembly with screws to thestabilizer and to the tailpost. Attach the topstabilizer fairing and secure with screws.5. Attach fin and stabilixer support wires to top offin using 2 mm screw and nut (from top side of


an integrated part of the fuselage. The wheelsare secured with locking rings and the wheel capsare pushed onto the wheel hubs.

BalancingThe center of gravity / balancing point should beapprox. 15 cm (6") measured from the leadingedge on the upper wing. Make adjustments ifnecessary.

FlyingThe prototype was flown with a OS 1.20

4-stroke FS which provides ample thrust. Let theengine swing a 18x6 propeller if possible. Thisgives better thrust outside the big dummy engineand reduces sound to a more realistic level.

Flying characteristics are very forgivingand will fly hapily on half trottle. Set the elevatorat zero angle for the first flight but be preparedto give down elevator if the model climbs out toosteep. During the initial take off run you have tocompensate for the torque with right rudder butas the speed builds up the rudder is returned toneutrual. This model should fly of the ground andnot be pulled.

The landing approach can be rathersteep as per prototype but the flare out needsalmost full up elevator. Maintain directionalheading and remember, the aircraft has astearable tailwheel.

Happy landings!

stabilizer to top of fin).6. Secure and tighten all screws and nuts.Check the action of elevator and rudder. Theelevator is actuated with the joy-stick and therudder with the rudder bar.

Assembly of wing panels1. Push the lower wing halves into the holes

in the fuselage.2. Attach the upper wing center section using

the 4 Allen 6-32 screws supplied (note that thefront screws are longer and the rear screwsshorter). Attach ball links or clevices to the aileronpush rods. Connect the aileron push rods to theservo in the fuselage.. Check the movement ofthe ailerons. 20 up and 15 down throw.

3. Install the interplane struts. Connect theflying wires and the landing wires. Attach the fly-ing wires in place. Attach the landing wires inplace. Adjust if necessary, the rear lowerincidence adjustment screw and the fasten thisassembly to the bracket on the lower wing using2 mm screw and locknut.

Should you need to replace a wire, use theattachment method indicated in the picture. Whencrimping the cerulet (sleeve) use a flat plier, pressfirmly and don't cut through the wire.

Landing gearInstall the wheel shafts and secure with the

Allen socket locking screws. The landing gear iscompletely built up with oleo spring action and is


Rudder and elevator servos in the flooringof front cockpit

Aileron servo in theflooring of rearcockpit. Note theservo arm with 2attachment pointfor the clevices ofthe aileron pushrods.

Push rods from the servos attach to therudder bar and the control column.

The tailwheel iscoupled to therudder bar and has50% throw of therudder

The OS 1.2 engine blends nicely with thedummy engine


What is in the box:The ARF kit contains the parts shown in the picture.All the parts are covered and painted. All the rigging

wires are supplied in the correct lengths and needonly to be clipped to their positions.

1. Fuselage with wing cabane2. Landing gear3. Scale wheels4. Dummy engine with mount5. Scale propeller6. Tail wheel assy (stearable).7. Fin with tailfairing / rudder8. Stabilizer / elevator

9. Upper wing panels10. Lower wing panels11. Interplane struts12. Wires, turnbuckles and hardware for assembly

(not shown)13. Assembly manual with scaledocumentation

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Boeing-Stearman Kaydet PT13_17