Scale 3-Blade propellers — Building a Ziroli Static Scale Kit — Part 1

Apr 26, 2012 No Comments by

Any scale warbird benefits dramatically with a scale prop added to the engine. Though you can’t fly with it, a scale propeller makes the whole plane look more realistic as it sits on the flightline. For scale competition, one is absolutely required for maximum static judging points! Whether you are a scale competitor or a sport flyer that enjoys giant scale warbirds, here’s how to produce a great looking addition for the nose of your fighter.

 

Hamilton Standard made 3- and 4-blade propellers for many fighter aircraft and the kit from Nick Ziroli Plans is ideal for the round nose such as the Curtiss F4U Corsair as well as the Grumman Hellcat fighter and the Douglass SBD Dauntless Dive bomber. You’ll have to do some research to get the diameter right and for my Top Flight 86.5 inch F4U Corsair, a diameter of 26 inches was just about right.

The kit comes with three resin-cast propeller blades, several laser-cut plywood hub parts, a pitch gauge and vacuum formed front and back hub covers. The whole kit can be assembled with a few hand tools using the included parts, but I wanted to make a stronger and more detailed hub assembly. To do this I used a couple lengths of PVC pipe from the hardware store as well as a few bits and pieces from the workshop spare parts drawer. Let’s start putting this thing together

1. Here are some of the stock kit parts. I used the center hub triangular parts and replaced the vacuum-formed parts with PVC pipe material.

 

2. For this scale size propeller, I used 1 ½ inch and ¾ inch PVC pipe cut to the approximate lengths to form the main hub housing and the three prop blade sockets. The nominal dimensions of the pipes are 1 7/8 inch and 1 1/8 inch respectively. PVC pipe is real cheap! For a 5 foot length of 1 ½ inch pipe it cost less than $3.00 and even less for the ¾ inch pipe.

 

3. To mark the three equally spaced lines for blade placement, I made a CAD drawing for a guide. You can also use the included instruction sheet that comes in the Ziroli kit.

 

4. Using an old model rocketry trick, I placed the pipe onto to the top edge of a desk drawer, closed the drawer and drew the lines perfectly parallel to the centerline of the pipe.

 

5. After cutting the hub section to the proper length, I placed it in my drill press vice and used a 1 inch forstner bit to slowly cut the openings in the side. Use slow and steady pressure to cut through the side of the PVC pipe. You are doing it right if the material comes off in long thin ribbons.

 

6. After the holes were cut, I used the bent sander to sand the hub diameter down to 1 ¾ inch. I also used the sander to square off and smooth the ends of the hub.

 

7. The proper width is determined by the kit’s triangular plywood pieces that are glued together. Here the hub triangle has been slipped into place within the PVC pipe. As a note, the distance from the flat sides of the triangle to the out surface of the PVC hub housing is ½ inch.

 

8. Next I turned down the smaller PVC pipe pieces to fit snuggly into the openings in the hub housing. I used my Taig Micro Lathe to turn down the parts. I bought the lather more than 20 years ago from Hobby Lobby International, but if you are interested in one, they are still available from TAIG Tools, 12419 E. Nightingale Lane, Chandler AZ 85286. email – sales@TaigTools.com or Phone (480) 895-6978.

 

9. After trial fitting the diameter of the pipe to the hub housing, I set the depth of cut and turned down the other two blade sockets to match.

 

10. Since I wanted the sockets to stick out from the hub ½ inch, I made the overall length 1 inch. I set the length and cut all three sockets to size. After cutting and facing the socket pieces to size, I switched tool bits and counter-bored the sockets (about 1/2 inches deep,) to fit snuggly over the base ends of the prop blades.

 

11. Here’s the hub assembly parts test fitted together.

 

12. Here you can see counter-bored inner surface of the blade socket.

 

13. Here the sockets are slipped onto the bases of the prop blades.

 

 

14. Here the Ziroli kit pitch gauge is shown supporting the prop blade and setting the proper angle.

 

15. Here an overall view of a prop being fitted in place on the hub assembly!

That’s it for Part 1. Come back soon for the details on how I prep, prime and paint the prop blades and detail the hub housing! See ya then!

 Check out the Propeller kits and other great Scale Accessories from Team Ziroli at: www.ziroliplans.com

 To see part 2 flick the link: http://www.modelairplanenews.com/blog/2012/04/30/scale-3-blade-propellers-%e2%80%94-building-a-ziroli-static-scale-kit-%e2%80%94-part-2/

 

Gerry Yarrish

About the author

Senior Technical Editor About Me: I have a lifelong passion for all things scale, and I love to design, build and fly scale RC airplanes. With 20 plus years as part of the Air Age family of magazines, I love producing Model Airplane News and Electric Flight.
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