It can be said that I like airplanes. I haven’t seen one yet that I didn’t like! Be it a new Cirrus Turbo or an old J-3 Cub – there’s just something about them that gets me excited. With that said, I really like those with a “special purpose”. You know, those aircraft that seem to have a limited market, but excel at what they’re designed to do? The Piper PA-25 Pawnee is one of my favorites in the “special purpose” category.
Now, there are a lot of agricultural spray planes on the market – some have radial engines, while others are powered by a turbine driving a propeller. The PA-25 has neither of these, but rather a flat, six-cylinder engine. This is not a plane you’re going to take your family for a ride in on a Sunday afternoon. But, if you want to go for a real ride (short of an air show performer), then look no further than an Ag-plane!
I first saw the World Models Pawnee at the Toledo show in 2011, and I’ve wanted one ever since. So, when the chance to review it came up, I jumped in with both feet! At 1/4 scale, it’s a large plane – the wingspan is nine feet and she tips the scale at a little over 20 pounds! I’m installing a DLE-55 gas engine, so I’m expecting some real Ag-plane type performance!
Let’s get the box opened up and see what we’ve got!
Name: The World Models 1/4 Scale Piper PA-25 Pawnee
Price: $649.99 (accurate at time of review)
Item Number: A318
Wingspan: 108 in (2740 mm)
Wing Area: 1302 sq in (84 sq dm)
Weight: 20.5 lb (9.3 kg)
Length: 68.5 in (1740 mm)
Center of Gravity: 3.9 in (100 mm) Back from the wing’s leading edge at the fuselage
Radio Used: Futaba 7C
Engine Used: DLE-55 Gas Engine
Channels Used: 5 total – Aileron, Elevator, Throttle, Rudder, and Flaps
Elevator: Up 1 3/8″ (35mm) Down 1 3/8″ (35mm)
Rudder: Right to Left 1 1/4″ (80mm)
Ailerons: Up 3/4″ (20mm) Down 3/4″ (20mm)
Flaps: Down 2″ (50mm)
- ARF Construction – Easy to Assemble
- Two-Piece Wing for Easier Tranporting
- Pilot Included
- Toughlon Covered with a Painted Fiberglass Cowl
- All Needed Hardware Included
- Functional Flaps for Smooth Landing
- Minor assembly items – see text for details
Time Required to Build
The Pawnee arrived in a large box – possibly the largest box short of a shipping crate I’ve ever seen! All of the contents were packed well and there was no damage to any pieces. There are only a “handful” of major parts, but most of them are quite large!
There were several items that I really liked. Though the fiberglass cowl is less than scale in profile, it will almost completely hide a DLE 55 inside it. The main gear is very robust, and there are two access hatches in the belly of the fuselage. I also liked the one-piece, painted canopy.
A few more things that caught my eye were the included pilot figure and instrument panel, the heavy-duty tail wheel assembly, and the plastic servo hatches with the servo mounts molded into the assembly!
The manual included with the plane does a good job of walking the assembler through the process. Though there are very few written instructions, the illustrations do just fine.
Assembly began with securing the aileron and flap servos to their respective hatches, followed by attaching each of the hatches to the wings. I really liked the control horns included with the plane. Though they took a bit more time to install, they looked great!
Reviewer’s Note: There were several long servo arms included with the Pawnee – they are designed to be attached to a round servo wheel with four machine screws and nuts. I decided not to use them, because the slots in the hatches would have had to be opened up significantly. I used DuBro Super Strength long servo arms instead. The slots needed very little modification for the optional arms.
The pushrods were assembled and installed next – be sure to use the proper rod on each control surface, as there were two different lengths. Another item I really liked was that all of the pushrod clevises were secured with machine screws and locking nuts!
The wing struts attached to the wing easily, though I did find one minor problem. I had to elongate the slots in the struts where they attached to the wings. This was done to allow the proper fitment of each strut to the fuselage during assembly
Tail and Tail wheel Installation
Moving on to the tail, I started by installing the wings to the fuselage. There were two large aluminum joiners that slid into pockets in the wings and fuse. The covering was then removed from the tail area, and the horizontal stabilizer was slid into place. After checking the stab/wing alignment, the stab and fin were epoxied in place.
I then installed the control horns on the rudder and elevator, and secured the control surface hinges to the stab and fin using epoxy. Adding petroleum jelly to the each pin assured that they would not get epoxy in the hinge and it would move freely. The tail wheel bracket is assembled at the factory, so all that was left was attaching it to the fuse, and installing the tiller arm and springs.
Main Landing Gear Installation
The main gear was attached to the fuselage using six plastic straps and a dozen screws. The covering had to be cut to allow the wire gear to slide into the notches in the fuse.
After grinding a flat area on the bottom of the axle, a wheel collar was installed – followed by the wheel and a second wheel collar. Be sure to add a drop of thread locking compound to each set screw in the wheel collars to keep them from coming loose! Lastly, a white wheel cover was installed using three screws.
Powerplant and Fuel Tank Installation
I drew up a spacing template for my DLE 55, taped it to the firewall, and drilled small pilot holes in the four mount locations.
The Pawnee has a long nose, so additional spacers were needed to set the correct firewall-to-prop hub distance. I had these aluminum spacers cut from aluminum at a local machine shop. The dimension of my spacers were 1″ x 1 1/2″ x 4″ and cost me a whopping $6.00 for the pair! Because of this, I also purchased four 5x70mm bolts to secure the engine stand-offs and spacers to the firewall.
The DLE 55 was then bolted to the stand-offs. The extra bracket attached to the lower left of the engine was for the Bisson Pitts muffler – more on that in a bit!
Using the included, clear, cowl template made trimming the cowl a simple task!
I then installed the throttle servo and pushrod (which required bending to clear the fuel tank), followed by the fuel tank. The tank is held in place with two large zip-ties.
I attached the Bisson muffler to the engine, secured the ignition module to the firewall and fabricated a choke pushrod. The cowl was then installed with four screws, and I added a DuBro Fuel-it fueling system – this is one of my favorite DuBro items, and almost every one of my planes has one!
The prop and spinner installation completed the nose of the Pawnee. I used a Falcon 22×8 propeller with the DLE 55 – you’ll read in the flight report how impressed I was by this combination! One more detail on the spinner: it also has a clear template, and the spinner had to be cut to fit the prop.
DLE-55 Gas Engine Spotlight
DLE-55 Gas Engine Spotlight
The two things you can count on in giant scale – The first is that you can always use a little more power, And the second is that there’s a DLE engine to deliver it.
Two crankshaft bearings-simple design for lighter weight
Aluminum alloy crankcase
Four petal V-type reed valve bottom induction system
Fully automatic electronic ignition
Two year limited warranty through Hobby Services beginning at date of purchase
- Type: 2-Stroke Gas
- Displacement: 3.39 cu in (55.6cc)
- Bore:1.77 in (45mm)
- Stroke:1.38 in (35mm)
- Cylinders: Single
- Total Weight: 55.3 oz (1570 g)
- Engine (Only) Weight:47.6 oz (1350 g)
- Muffler Weight:3.5 oz (100 g)
- Ignition Weight: 4.2 oz (120 g)
- Benchmark Prop: Xoar 22×8 PJA Beech Prop
- Prop Range: 22×8 – 23×10
- RPM Range: 1,350 – 8,500
- Fuel:Unleaded Gasoline/Oil at 30:1 mMix
- Muffler Type: Cast
- Cylinder Type: Ring
- Crank Type: Ball Bearing
- Carb Type:Walbro
Bisson Wraparound Inverted Pitts Muffler Closer Look
Looking for A Really Nice Pitts Muffler? Bisson’s line of Mufflers are generally designed for engines mounted inverted. Each muffler is made to replace the standard muffler using the existing mounting bolt location and exhaust pattern. The Wrap Around Pitts Style Mufflers are light weight and offer large expansion chambers. Bisson offers a large selection of mufflers to meet a wide variety of engines!
Elevator and Rudder Servo Installation
I really liked the double-servo set-up for the elevators. One minor concern with this was that each servo had to be on its own channel, or a servo reversing Y-harness was needed. Luckily, I had such a Y-harness on hand! Installation of the elevator servos and pushrods was exactly the same as the ailerons. The rudder was a pull-pull set-up – a threaded rod was used for the control horn, and was held in place with two locking nuts.
After the connectors had been turned onto the threaded rod, the clevises were attached to the wires, and the wires were pulled through the fuselage. I then installed the servo and included arm for the rudder.
Tail Bracing Wire Installation
The tail bracing was easy to install, and started with attaching the six brackets (a metal bracket was installed with the tail wheel assembly)to the stab and fin. I then assembled and installed the four bracing wires and connected them with the included pins.
Pilot Figure, Instrument Panel and Canopy Installation
It’s time to add some detail! The instrument panel fit nicely, so I simply glued it in place using some medium CA. The included pilot figure was not tall enough to “see” over the panel – The World Models has added a black foam spacer to make the pilot taller. There were two pieces of double-sided tape included as well. These help secure the foam spacer to the cabin floor, and the pilot to the spacer. A pair of black zip-ties strapped the pilot in.
The instruction manual stated to install the canopy with epoxy, but I don’t like doing that. Instead, I used some small screws to secure the canopy. Small pieces of light ply were glued to the inside of the fuselage for the canopy screws to ‘bite’ into.
The wings were the last item to be added. The joiners were slid into their respective pockets in the fuselage and the servo wires were connected. I then slid the 255mm threaded rod through the brass tube in the fuse, and secured the wing struts with two washers and locking nuts. To make this step easier for field assembly, I added thread locking compound to one of the locking nuts. That way, one of the nuts is permanently held in place, while the other can be removed.
The four aluminum straps were installed on the bottom of the wings – again, I added a drop of blue thread locking compound to make sure they wouldn’t vibrate loose and fall out while the plane was in the air!
Lastly, I checked the center of gravity (CG), and it was right on target at the recommended 3.9″ back from the leading edge of the wing.
That’s it! It’s time to take the Pawnee outside and fly!
My DLE 55 was still new, having only been run once before. I decided to run a tank of fuel through the engine on the ground. When the tank was empty, I checked the Pawnee over for loose screws, etc. (I didn’t find any) and then re-fueled.
Since I am able to fly at an abandoned airport, I have the ability to take off into the wind from any direction. The day of the maiden, we had a decent breeze blowing at around 10-12 MPH.
I taxied out to the runway, and noticed immediately that the rudder and steerable tail wheel did a great job of directing the plane.
With the nose pointed into the wind, I advanced the throttle gently. The tail came up within just a few feet, and the main gear left the pavement in less than 30 feet! The throttle was only half open! Gaining altitude was no issue – the DLE 55 and Falcon 22×8 prop had more than enough power to pull this big plane around.
Half a lap around the sky, I felt so comfortable with her that I pulled into a loop – again, the DLE 55 pulled through with no problem! Rolls were a bit sluggish and required ‘down’ elevator input while inverted, though I’m thinking that had a great deal to do with the 9 foot wingspan.
With the 22×8 prop, flying too fast was not a problem – even at full throttle, I had no concerns with the Pawnee. Flying slow did require a little back pressure on the elevator stick, but was easy to do. With the flaps down, this plane really slows to a crawl without ballooning at all!
After a 10 minute flight, I lined her up for a landing. Flaps down, with a just a touch of throttle, seemed to be perfect for controlling the decent – and a gentle touch down. Bringing in the Pawnee was easy!
After shutting down the engine, I drained the fuel from the tank. The 800cc tank took 90 cranks on my pump to fill, and after 10 minutes of flying, I pulled almost 60 cranks of fuel out! The Pawnee, DLE 55 and Falcon 22×8 prop were a great combination of performance and fuel economy! At this rate, the plane could comfortably stay in the air for 20 -25 minutes without running out of fuel – though I recommend you check your own flight times and adjust accordingly.
It took me about 18 hours to assemble the Pawnee, and I didn’t rush through it. I flew the plane and can only describe her as a “gentle giant”. She’s a great looking plane, both on the ground and in the air! If you’re looking to step up to a 50cc sized plane, the Pawnee is a great choice – easy assembly, easy flying, and easy on the eyes!
The World Models
4749 – K Bennett Dr.
Livermore, CA 94551
DuBro Products, Inc.
P.O. Box 815; Wauconda, IL 60084
Phone: (800) 848-9411
Futaba Corporation of America
Great Planes Model Distributors
P.O. Box 9021; Champaign, IL 61826-9021
Bisson Custom Mufflers
9 Moffat Rd; Parry Sound, Ontario, P2A 2W7
Phone: (705) 389-1156
Great Planes Model Distributors
4105 Fieldstone Rd.
Champaign, IL 61822
Phone: (217) 352-1913