The next project was to create the motor mount for the G-75. The Bobcat has sort of a universal mounting block system for the engine which was originally intended for a 50-60 sized engine. Unfortunately the G-75 has a bit deeper footprint over a 50 and needs a custom mount. Luckily my friend Andreas was kind enough to make two of these beautiful motor mounts (one for me) in appreciation for the custom muffler modification :0)
       Notice the stock engine blocks on the right, they are much shorter than the “Andreas” blocks. We had calculated about a 2-3 degree down-thrust needed for the plane to not to climb while accelerating. Andreas had built the angle into the blocks before hand....

       I used some 80 grit sandpaper to rough up the finished surface on the motor mount deck and epoxied the engine blocks to the deck. I then used some “dove gray” Top Flite LustreKote paint to match the fuse.

       I decided to use some blind nuts on the bottom side to hold the engine bolts. Longer M4 bolts were needed to replace the short stock mounting bolts supplied with the Bobcat.

         Notice the spinner nut and washer on the engine. I used a Dubro (cat # 731) 5/16”-24 spinner nut along with an OS .61-.90 Steel prop washer (Tower cat # LXCT76) to hold the prop securely. This will also aid in starting the G-75.

       Earlier I had purchased some silicone tubing for an exhaust deflector. My original intentions were to plumb the exhaust though a hole in the wing and point it towards the ground using this tubing. Later in the build my friend Andreas had come up with the brilliant idea of plumbing it through the center of the fuse so that is exactly what we did.

       With the exhaust tube in place I was able to install the throttle linkage using the stock push rod.

       The next step was to install the fuel tank. The stock tank (lower right) was a little too small for the thirsty G-75 so I decided to use the Hayes 16 oz Slimline fuel  tank (cat # 146) instead.

       The front “spar” wire unfortunately causes a bit of an obstruction for the fuel tank so a slight modification to the former must be made to fit this tank. Notice the top of the former hole has been raised a bit.

       Using some foam padding I made a fuel tank cradle that once in the fuse will hold the tank securely. Notice that the tank sits with the clunk towards the back. The fuel tubes are routed to the front of the tank.

       I mounted the muffler to the engine and installed the fuel lines as well. (Later on I would discover that the muffler gasket should be left out as it will most likely blowout anyway. I used a thin film of JB Weld on the flanges and then tightened the bolts quite a bit. Blue Loctite should also be used on the muffler bolts to prevent loosening.)

       I could now focus on the radio gear and install the throttle and nose wheel servos. Notice that the control rod for the nose wheel is at a diagonal. This is to allow maximum travel with proper geometry.

       The stock nose wheel wire was a little short for this kit so I opted to buy a Dubro 5/32” nose gear wire (cat # 154) to get a little extra length so the nose does not sit too low. I also used a Great Planes Wire Axle (cat # GPMQ4281) so I could adjust the ride height of the nose wheel. The Bobcat has it’s main wheels quite a bit behind the CG so a short nose wheel gear will cause the jet to “jump” off of the runway on takeoff.
       If the nose wheel is properly adjusted the jet will leave the ground in a predicable manner. Later on we would discover that 145 mm from the bottom of the wheel to the bottom of the fuse worked well as a starting point. (The mains were also 145 mm to the bottom of the wing.) Notice the gear wire is left long for adjustment. It can be cut once the proper ride height is set.

       You may have noticed that I decided to use different wheels than the ones supplied. I am not a big fan of huge foam wheels on jets so I toned it down a bit by installing a 2” wheel on the nose and two 2.5” wheels on the mains. (Dubro cat # 200T+250T)

       After doing some preliminary CG calculations I figured that the battery pack must be in the nose of the plane (probably to compensate for the large engine). I wrapped up the 1500 mAh pack and pushed it into the nose of the jet. Notice that I cut out the vertical brace of the nose wheel bulkhead. It really isn’t needed.

       I cut out two foam blocks to “wedge” the pack into the nose. It actually worked real well :0)

       My fellow modeler Andreas was kind enough to construct me a control panel to mount inside of the canopy. I used it to support my Hobbico VoltWatch II. I should be able to see the battery condition thorough the canopy.

       The receiver was next to install so I cut out another foam block to support the Futaba receiver which worked very well. Not only did the block support the RX it also hides the wires coming in from the wings.

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