The World Models 1/6 Scale Piper Pawnee: A Kit Review – Part One – Building the Airframe

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The Piper Pawnee has been a long-time favorite among modelers of all types, and especially those interested in Agricultural aircraft. I myself am a huge fan of these aerial applicators! The Pawnee is kind of like a low-wing Cub – It flies well, carries a lot of weight, and does its job very well! While some may argue that the Air tractors and Ag-Wagons look better, I have always liked the Pawnee’s distinct appearance best! With the advent of larger and more technically advanced ag planes, the Pawnee has lived on as a banner and glider towing aircraft – while they enjoy retirement from spraying, kick back and enjoy this kit-build review of a classic aircraft!

First Look

Like all of the World Models boxes, a colored end-wrap adorns an otherwise plain brown cardboard box. Though the Pawnee also comes as an ARF, you won’t find that to be the case with THIS model! That’s right – this one’s a box of wood!

Some of the key parts have had some pre-assembly done at the factory – that’s because the manufacturer felt that these are important steps that needed to be done precisely.

Removing all the bundles from the box, you’ll find that they’re taped together by airframe part – Fuselage, wings, and tail surfaces. All of the wood was nice – not too soft, but not hard and brittle either. The laser cutting was done well, and required very little edge sanding! The light ply is very nice as well!

Now here’s something you don’t see very often with a kit – a full set of HARDWARE! Yes, almost every piece of hardware you’ll need to build the Pawnee is INCLUDED! This was a very nice touch on the part of the World Models!

One key item I want to point out is that you should decide how you’re going to power your Pawnee before you purchase the kit. If you decide to use a glow engine, you’ll need to provide your own fuel tank and engine mount – or you can purchase the glow engine option package from Airborne Models for about $10.00! If you decide to use electric power, Airborne has you covered there, as well, with an electric power option package!

The best part is that most of the bags are even labeled by the associated number in the instruction manual – this way, you won’t end up with all the bags open and little pieces rolling around on your bench!

The canopy came out of the box painted blue, so if you’re planning a color scheme that doesn’t jive with a blue canopy, you’ll have to plan on painting it a different color. I like that the World Models includes a pilot figure with nearly every model they sell, but I think I’ll be looking for something a little more realistic.

Required Adhesives and Special Tools

Aside from your basic building tools (Razor blades or Xacto knife, sand paper and sanding bars) I find there’s a couple things I have to have – A small piece of glass and a builder’s square. These two tools help me to build quickly, easily, and most importantly straight and square!

The other item you’ll need is adhesives. For this build, I’ll be using ZAP brand adhesives. Three different thicknesses of CA, CA accelerator, Formula 560 Canopy Glue, and 5,15, and 30- minute epoxy were all used to build the Pawnee! These adhesives are available at your local hobby shop and online at www.franktiano.com.

Manual and Plans

As you can see, there are two manuals and two sheets of plans that come with the Pawnee. One manual is the building instructions, and the other is the ARF assembly manual. Essentially, the building manual will walk the modeler through turning the piles of wood into an ARF – that’s where the second manual takes over! The second instructs the modeler on how to assemble the individual pieces after they have been completed, and it also covers installation of the chosen power source and radio gear.

The plan sheets are, believe it or not, simply included for reference material. They are not full size, and the Pawnee is NOT assembled on the plans! They are a helpful visual tool, though, and you may want to turn them into art when the Pawnee is complete – that’s what I did…

Building the Fuselage

Per the manual, I started by removing all the fuselage parts from the balsa and light ply sheets. There’s a lot of light ply in the fuse, and it’ll take you some time to cut and remove the parts. A light sanding helped to remove any wood not removed by my X-acto knife and #11 Blade.

The left fuselage side was tightly taped to the right side, followed by the light ply bottom tail section. No glue has been used yet – that will come later!

With the fuselage sides and bottom tail section taped together, F10 and F31 are pressed into place. A few small pieces of tape held F31 in it’s correct position, and F10 stays put thanks to the notches in the fuselage sides.

 The fuselage was then laid on its left side to begin installing the formers and landing gear mounts. I used a builder’s square to ensure that the F5 formed was perfectly aligned while the CA cured. The middle section of the landing gear mount is a ‘channel’ comprised of three pieces of light ply. They are glued together before installing into the fuse.

The assembled channel was then glued into its slots in the left fuselage side, along with the wing strut attachment block, servo tray, landing gear mounting blocks, and upper former F5B.

Former F4 was slipped into place, and the fuselage sides were tightly taped to the two formers. The remaining formers (F6, F7, F8, and F9) were then installed into notches in the fuselage  sides.

The white antenna tube (Some modelers still prefer a 72 mHz radio system) and two black pushrod guide tubes were installed into pre-cut holes in the formers. NOTE- IF YOU HAVE INSTALLED ALL OF THE FORMERS CORRECTLY, THE TUBES WILL SLID INTO PLACE EASILY!

Moving on to the front end of the fuse, I installed the fuel tank/battery tray and F3. According to the instructions, F3 is installed before the tray, but I found it easier to install the tray first, followed by F3.

Former F2 and the firewall were installed next, and went in easily. The instructions recommend using Epoxy for the firewall, so I mixed up a quick batch of 5- minute Z-Poxy. You’ll want to be careful about adding too much epoxy at this time, because there will be tri-stock added as reinforcement later. Go sparingly on the epoxy now, and re-coat later if needed!

Time to add some glue! I used medium CA and some ZIP Kicker to glue the fuselage together. The kicker is needed because there’s a lot of light ply used in the construction of the fuse, and CA doesn’t always adhere well in ply joints. Make sure to apply glue to each side of every part and glue the fuselage together solidly – even gluing the pushrod guide tubes in place as well as possible!

After gluing the two belly stringers in place (the two share a notch in former F7), the rear belly sheeting was installed. the sheeting is pre-assembled at the factory, and fit perfectly! Turning the fuselage over, and using a long CA tip, I glued the sheeting in place with medium CA.

Two ‘plugs’ (F23A) were glued into the landing gear channel installed earlier. I found it easy to install the parts first and then glue them using some thin CA. The light ply landing gear belly cover (F26) was glued in place using thick CA to fill in any gaps that may have been present. There will most likely be some stress on this part, and I wanted to make sure that there were no places that didn’t get glued properly.

Pre-cut tri-stock was then glued to the landing gear blocks and light ply belly for additional strength – the gear will definitely stay in place with all this reinforcement!

Moving on, the forward stringer and belly piece were installed using medium CA. The top and bottom firewall supports (the lower having had the fuel tank rest glued in place prior to installation) were glued in place as well, and the previously mentioned tri-stock was added to both the inner and outer sides of the firewall.

The wing tube sleeves were ‘roughed up’ on the ends before being glued into their pre-cut mounting holes. They were slightly longer than the fuselage was wide, so a little trimming and sanding was in order after the CA had cured.

The pre-cut turtle deck stringers and spacers were installed next using medium CA. The stringers are slightly longer than required, and a little sanding will be done later.

I gathered up the cockpit floor parts, and started installing them. with the floor piece in place, the four light ply canopy mount plates (F18A) were glued between the floor and the top of the fuselage. Make sure you leave space for the outer sheeting that will be glued to the outside of the canopy mounts and top of the fuselage. This sheeting does require a slight twist when installing, so a medium or thick CA will give you a good working time to get the sheeting placed correctly.

The front of the stringers and spacers were then sanded flush and the rear cockpit sheeting (F7A) was glued in place.

The front turtle deck was installed next, and was slightly more difficult that the rear. The pre-cut stringers MUST be installed per the instructions, or they will not be long enough – as they were, they just barely fit! The one-piece sheeting was then glued in place after I wet the outside with water  and shaped it. F5A and F6A were glued to the front and rear of the front turtle deck, sanded to shape. A quick check-fit of the canopy let me know that I had the turtle deck sanded to the correct shape!

The tail filler block (F32) is glued in place next. After sanding the stringers flush with the back side of former F10, I wrapped the center section of the horizontal stabilizer with masking tape – this was done for two reasons. I didn’t want the stabilizer to accidentally get glued in place, and the tape provides a little space to allow the covered stab room for final installation. I used thick CA to glue the tail filler block in place. When the CA had cured, I removed the stabilizer and sanded the filler block to shape – the pushrod guide tubes were trimmed and sanded smooth as well.

The basic fuselage has been completed – it’s time to build the battery/fuel tank hatch!

I started the battery/fuel tank hatch by laying out all the parts and taping off the hatch area on the fuselage. I used some clear packing tape to cover the hatch area. This allowed me to build the hatch in place, so it was built at the proper angles while not being permanently glued in place!

Three parts made up the front end of the hatch, and were glued together using medium CA. When the CA had cured, the hardwood dowel was slid into the hole in former F1. I ran into one small issue here, in that the hole for the dowel was not cut in F48 by the laser. A few quick measurements had the hole located and drilled, and I was moving on.

The rest of the main frame parts were glued in next, and presented no issues. Thick CA and some ZIP Kicker helped the light ply joints stick together well.

The pre-cut hatch stringers were installed next, and were just the right length! The outer sheet strips fit nicely into the former slots, but required a little twist and hold while the CA cured. With the tape still in place, I sanded the hatch lightly to match the fuselage.

And here’s the final result! A hatch that’s built to match the fuselage, and it was really easy to build as well! We’re done with the fuselage for now, so let’s move on to the wings!

Building the Wings

I started by removing all of the wing parts from their laser cut sheets. Some of the thicker light ply parts are a little tough, so you’ll want to have a sharp blade to cut the parts free. Like the fuselage, you’ll notice that some of the parts have been pre-assembled at the factory.

With all of the parts free from the sheets, I laid them out to make sure all were present. When building the wing, pay close attention to which sheet parts go where, and in what direction they face. There are several parts that have pre-cut holes, and MUST be installed properly for future parts fitment!

 Wing assembly is straight forward and easy if you follow the instruction manual – You’ll notice that I’m not building the wing over the plans! The parts fit so well that no plans are necessary. The most important thing to remember about building the wings is this – use enough glue to hold the parts together, but don’t use too much – there will be time to add reinforcement to joints later. The main wing spar is constructed of three pieces – an upper and lower balsa stick (W12 / W12A) and a balsa center section (W13) that has laser cut notches for all of the wing ribs. W12A is glued to the face of W13 at the bottom edge, following the instructions. The root rib, which is pre-assembled at the factory is set at an angle for the correct wing dihedral. Pay close attention to the fit of the spar-to-root rib joint, and you’ll do fine. The rest of the ribs and hatch mounts nearly fell into place, and made building easy!

The leading and trailing edges were installed next, along with several small pieces of tri-stock (W23) that add strength in high stress locations. The upper balsa stick (W12) is glued to W13 and all of the wing rib notches to complete the main wing spar.

I roughed up the ends of the wing tube sleeves before gluing them into place – once the CA had cured, I trimmed the protruding ends and sanded them flush. Moving on to sheeting, the first thing I did was lay out all the individual pieces and placed them in order as to where they will be glued to the wing.

All of the sheets fit very well, and required no trimming or edge sanding! I did sand a 45° bevel into the leading edge sheet on the side that got glued to the ribs – this helps the sheet’s edge fit better to the back side of the leading edge. The sheet was also taped to the leading edge to keep it in place while I applied thick CA to the ribs.

The sheeting for the bottom of the wing went on in a similar manner, with just a few different pieces for the aileron and flap servo hatch cut-outs. Again, every piece fit nearly perfectly!

Here’s where that piece of glass I mentioned comes in handy. The edges of the glass are wrapped with black electrical tape to keep me from getting cut. I laid out all of the parts for the wing tip to make sure I had all of them, then proceeded with assembly. The wing tip is easy to build using medium CA and some ZIP Kicker. I like using the piece of glass not only because it’s flat, but also because CA doesn’t stick to glass very well. So, if I accidentally glue the wing tip to the glass, it can be freed easily!

With the round wing tip built, I sanded the flat ends of the wing and tip smooth. The two parts were glued  together using thick CA and just a little bit of ZIP Kicker. When the CA had cured, I took the wing outside and sanded the wing tip so it had the same shape as the leading and trailing edges.

The trailing edge at the root was glued in place, and the flap and aileron were temporarily hinged using the included CA hinges. At this point, I built the other wing half before moving on to temporarily attaching the wings to the fuselage. The wing tubes were slid into their respective sleeves in the fuse, and the wings were then slid onto the tubes. My wing tubes were a bit of a tight fit, so I gently sanded the ends of the wing tubes – this allowed a better fit without causing there to be any movement.

Building the Tail

Using my trusty piece of glass again, I glued the two rudder pieces together and checked the rudder to fin fit. The two parts fit together well, so I also test-fit the fin into the tail block. It fit just a little too tight for my liking, as I still have to apply the Toughlon covering, so I sanded the fin just a little until I was happy with how easily the parts went together. The pre-cut hinge slots in the fin and rudder are a nice touch, and made setup easy!

The elevator halves were also constructed of two pieces each, so they were glued together with thick CA just as I did for the rudder. I slid the horizontal stabilizer into the tail (the fin has to be removed because the fin and stab are ‘keyed’ to fit together ) and temporarily hinged the elevators to the stabilizer.

Here’s a couple of photos of the basic airframe, both assembled (left) and ready for covering (right). In Part two of the Pawnee review, I will be covering the individual parts of the airframe, before we move on to final assembly and flying!

Build Summary

When I first opened the Piper Pawnee kit, It looked like a whole lot of wood. But, amazingly enough, the airframe went together quickly and easily – this was due to some of the pre-assembly of important parts at the factory, but also due to the accurate laser cutting. Honestly, this is the first kit I have built in approximately 8 years, and I had the basic airframe built in about a week and a half, working on it an average of 2-3 hours per night! If you’ve never built a kit, I would definitely recommend the Piper Pawnee as it’s a good first kit project – the parts all fit and the manual was written very well! Stay tuned for the remaining parts of the review – they’ll be coming soon! – GB

Contact Information

Airborne Models: www.airborne-models.com

The World Models: www.theworldmodels.com

ZAP Adhesives: www.franktiano.com

G.Barber: email – gbarber726@gmail.com

 

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2 Comments

  1. nioa

    Pretty neat “in-between” building concept! Plans – ARF. I like the laser cut precision, and pre-assembly of parts that require high precision. Scratches that building itch, without having to start totally from scratch. Great idea that I hope catches on!

    Looking forward to the 2nd half of review, and flight report.

    Nick

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