The Graupner Starjet (ERCITS)
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The Graupner Starjet

By Shaun Cronin - Email: Shaun

Specifications: Wingspan: 47 inches; Wing Area: ~632 sq. in.; Wing Loading: ~ 11.4 oz./sq. ft.; Weight: 50 oz.; Recommended power: 2x Speed 400 6V; Servos uesd: 2x sub-micro HS-55 servos; Manufacturer: Graupner; Available from: Hobby Lobby

Kit Contents

The StarJet comes in an absolutely huge box. I almost couldn't fit it in my car to get it home. Since it is foam, there is relatively little packaging or padding in the box. I've been through two StarJets now (radio problems with the first), and both have had only a few minor blemishes, but nothing flight threatening.

The fuselage consists of two fins, the canopy/battery-gear cover, and the rest of the plane. Stickers, detailed assembly instructions, push rods, control horns, as well as a few other incidentals are also supplied

Assembly

First and foremost, you will need a supply of sharp hobby knife blades. You won't have to replace the blade after every cut, but don't be bashful about replacing a dull one. Your cuts will be cleaner and your building experience will be more enjoyable.

The instructions begin with cutting the aileron end slots. I opted to de-bur the plane first, which is listed as step two in the instructions. This process entails carefully cutting away the excess material from the foam molding process. Use a sharp blade and take your time. It is actually kind of fun.

Once the prep work is done, it's on to the hardware installation. That is all that is really left to do to finish building this plane. I began with the motor mounts. The design calls for the two speed 400 motors to be glued directly to the foam, one in each motor channel. I was planning to try out a few different motor setups, so this technique would not work for me. In addition, a mount would also aid in motor replacement in the event of bent motor shaft. The result was a simple compact removable motor mount detailed on the left.

The mounts are constructed so that the motors rest in the original mounting locations at the factory specified angles. The mounts are glued in place with 5-minute epoxy. You don't need to build this motor mount or use it for your setup, unless you plan to upgrade to hotter motors at a later date. Personally, I've found the Hobby Lobby recommended setup (two 6V speed 400 motors on eight 1900mah cells) to be a great performer.

The mount consists of two pieces 1/16" or 3/32" plywood, four pieces of spruce square stock, and two 2-56 blind nuts. I started out with a store bought speed 400 circular motor mount as a template. Along with the above photos, I have included a rough drawing with dimensions of the motor mount. Between the two, you should have enough information to build your own mount if you choose.

At this point only, the installation of the speed control, servos, and control rods is all that is keeping the StarJet on the ground. The elevator/aileron servos (HS-55s) are installed in the pre-formed foam wells. I did need to mount one servo in the opposite orientation to make use of my JR radio's elevon mixing. Use a sharp blade to modify the servo well as needed.

The elevons must be cut out before connecting the pushrods to the servos. Once again, the tool of choice (a sharp blade) makes short work of this task. There are molded cut lines on the bottom of the wing at either end of each elevon. There is no guesswork with the StarJet's high quality workmanship.

The supplied pushrods and clevises are precut to length and threaded at both ends. The elevon control horns are epoxied to the inboard ends of each elevon. First, scribe the edges of the control horn with a blade or file. This will help ensure that the epoxy will adhere to the surface of the fiberglass control horn. This is an important step, as the loss of an elevon would most certainly result in a loss of control.

I used a sharpened piece of brass tubing to cut a direct servo wire channel to the receiver. This alleviated the need for servo extensions.

I used the Jeti 25 speed controller (mounted with Velcro) and Sermos connectors.

The battery (8cell -1900mah) mounts to the battery tray with Velcro. It can be moved forward or aft for balance. The receiver is also mounted with Velcro. Everything fits nicely under the removable canopy.

The next step is to glue the two vertical fins in place with 5-minute epoxy. To prepare the main wing for installation of the fins, cut 60mm tall blocks and place them under each wingtip. Next, weigh down the center portion of the fuselage. This gives the StarJet a small amount of dihedral for stability. Once the blocks and weights are in place, carefully glue each fin in place. Make sure you mix plenty of epoxy so you don't run out during installation. Work on one fin at a time and leave the plane in its blocked position until the glue cures.

With the exception of a few decals and a little work with the control throws, the StarJet is ready to fly.

Flying

WOW! This plane flies great. I have been flying the Multiplex Twin Star for the past few months and it has become a real favorite of mine. The Twin Star is a fun, stable, four-function high wing twin. After the StarJet's first flight, I knew it was going to join the Twin Star ranks.

I asked Ken Johnson to hand launch the plane while I was ready at the controls. I spooled up both motors and Ken gave the StarJet a good firm throw. Starting out at about head high, the plane dropped a foot or so as it got on step.

I pulled up slowly on the elevator stick and the StarJet began to climb out nicely. I felt very comfortable and there was no trimming necessary. Right away, I was reminded of the smooth and familiar characteristics of my Multiplex Twin Star. I have been hand launching the StarJet since the third flight and it is every bit as easy to launch as my high wing Twin Star.

Conclusion

The StarJet floats gracefully around the sky at partial throttle and climbs nicely at half throttle. With full throttle, it's on to aerobatics. With its space-age looks and great twin sound, the StarJet is always an attention grabber. Landings are smooth and predictable. Just line it up, cut the throttle, and let it settle in. The StarJet is capable of extended flight times lasting upwards of eight minutes. Overall, the StarJet is a real pleasure to fly and is fast becoming my favorite all-round flier.

Reprinted courtesy of the Ezone magazine.

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This page created and maintained by Al MacDonald. Updated January 21, 2002.

ERCITS1 , ERCITS2 OR ERCITS3

Suggestions for improvements or additions to this page are always welcome.