JC's Planes and Projects

Top Flite Giant P-47 Thunderbolt

3/2/01 - For a few exta ponies and reliability I have opted to install the Zenoah G45 engine instead of the recommended US Engines 41cc engine. This is a more expensive route, costing nearly twice as much when you consider that an after-market muffler has to be purchased. Hopefully the performance and reliability of this engine will make up for the increased cost.

This shot shows shows the voluminous and almost fully sheeted fuse upside down on a Robart Super Stand II. The muffler is a Bisson inverted pitts muffler. No modifications were needed to accommodate the muffler. The fit inside the cowl is nearly perfect with the exhausts pointing exactly out the bottom of the cowl. Don't you love it when things work out like that?! Prop shown is a Zinger 20x10, although I don't yet know what I will fly with - I also have a 20x8 for break-in.

Here is the right side of the Zenoah G45. Note that I did use the recommended Great Planes Large Engine Isolation Mount. I did have to make one modification to be able to use the G45. The G45 is shorter front-to-back than the USE 41cc engine. I needed to push the engine out exactly 1/2" to get the distance from the firewall to the prop hub correct. I did this with the use of 1" diameter birch dowel plugs that I found at Home Depot. They are 1/4" thick, so I stacked two up to get the required stand-off distance. I glued them to the firewall and then used a drill press to center-drill them with a 5/16" bit using the pre-drilled holes in the firewall as a guide. Blind nuts of 1/4-20 were then tapped into the back of the firewall. This arrangement will allow a fairly easy removal of the engine if need be. The bottom of the iso-plate was also trimmed about a half-inch to clear the muffler. Other than that modification, the installation is stock.

Here is an "iso" on the iso-mount! Stand-offs too! Note that the closest mounting bolt and isolating donut is absent in this photo. I was fitting the throttle linkage at the time. Note how the B&B bell-mount is attached to the iso-plate from behind. The assembly is then attached to the firewall. Note that firewall is pinned in 16 places with 1/8" dowel stock. Muffler looks like it is rubbing on firewall but this is just an optical illusion. The isolation mount is actually very stiff due to the wide spacing of the isolation points.

Here is my custom tank mounting system. Top Flite just leaves you hanging on how to mount your tank. I chose a 20 oz. Dubro tank for my model instead of the recommended 32 oz. Great Planes model. Thirty-two ounces of gas on a 40cc engine would make for a very long engine run should the throttle get stuck. I went with the 20-ouncer for comfortable 15 minute flights and also the comfort of knowing that if I ever lose my throttle I'll run out of go-juice before I run out of battery juice! Anyway, the tank platform is 1/4" aircraft plywood. I then matched one-inch square feet to the bottom and ran it through with a 3/16" bit. I then glued 3/16" dowel stock to the platform. The feet were then mounted to the tank-floor in the fuse. The result is a very solid fit into the feet in the tank floor - so stable that it will be held in place with a single wrap-around of Velco. In addition, the tank can be removed without removing the servo platform. This cannot be done with the recommended GP tank. Throttle servo is also shown in photo. Tank feet appear on tank floor (at the top of the photo).