Graupner Starjet

 

Graupner StarJet Twin Graupner Speed 400/480 Electric powered model. 3/2 Channel Receiver Elevon mixing via transmitter or seperate mixer and throttle Battery packs 2000NiCd 9,6v 3000NMh 8,4v 2400NiCd 9,6v 2400NiCd 8,4v

Dimensions: Wing span: 1200mm Length: 780mm All up Weight: 1470 grams Wing Area: 632 Sq.In. Wing Loading: 36g/dm² Thrust: 600 grams

Model from Motors and Rotors, 13 Smith Street, Watford. Tel: 01923 465712.
Please mention Bumpy Green Model Aerodrome if purchasing a StarJet from them.

Lets Get Started...

So Whats in the Box?

Answer............

1 x moulded styrofoam body (1 piece fuz and wings), hatch and 2 fins
1 plastic skid pan.
2 Sheets of Instructions
A pack of accessories
1 Set of colourfull stickers

What else do you need?..

Suitable Battery Pack Transmitter capable of elevon mixing or seperate mixer 35A Speed Controller Motor Wire Mini Servo's x 2 Servo extension leads x 2 Speed 400 Motors x 2 Gunther propellors x 2 Receiver (at least 3 channels) 5 Minute Epoxy,

Building...

Cut down the elevon edges to free up the elevons. Do not move the elevons too many times until the stickers have been put over the hinge line. This will break very easily and will be difficult to fix.
Using a scalpel with a new blade fitted remove the moulding defects from all egdes of the model
Sand the GRP Control Horns so it gives the epoxy something to key to. Using epoxy, glue the GRP Control Horn to each inner end of the elevons, squeeze scrap balsa sheet into the gap to make the control horn press onto the elevon.
Throw away the plastic clevices supplied and fit metal ones to the threaded rods found in the accessories pack.
Glue the servo's into the place provided, making sure the control rod (when fitted) travels in the trench correctly and there is enough room to allow the servo arm and metal clevis to moved freely.
Solder the wires to the motors remembering as the motor is being used as a pusher that the black wire needs to soldered to the red terminal so the motor runs backwards. Allow enough wire so the pair of wires can run from the motor to the centre camber using the built in trenches. Put bullet connectors on the end to allow connection to the speeds controller, I soldered mine directly to the speed controller. The red wire from each motor is soldered to the red on the speed controller and visa versa for the black ones.
Glue both motors into the wells provided, remembering to roughen the motors so the epoxy keys to them and also that the air vents are horizontally opposed so the air can get into both sides of the motors.
Glue the skid pan to the underneath of the nose using plenty of epoxy and hold in place with some masking tape.
Tape the motor wires and servo wires so they stick to the bootom of the trenches, this allows better airflow and stops the wires flapping around during flight. Once this is done you can glue the two fins in place, using a good amount of epoxy.
The stickers can now be applied, the stickers which go over the hinge line of the ailerons are very important as they will stop the hinge from cracking and the elevon breaking off. All the other stickers are optional and i chose to use some, and add some designs of my own. I like to use thin trim tape to create pretend panel lines which looks very effective around the canopy.

Modifications - New hatch retainer...

To complete this modification you will need the following

3 x 1/16th ply pieces, the size of the top of the styrofoam block inside the nose (see below) 1 x captive nut 1 x bolt which fits captive nut 1 x washer

The method empolyed to secure the hatch, is by bending a bar supplied into a 'U' shape with one side alot longer than the other, this is then pushed into the front of the model so the longer side of the 'U' so when the hatch is to be secured the short part of the 'U' is pushed into the hatch. I did not like this method at all and searched for a better method. I spotted a hole in the moulding inside the hatch which lined up with a block of syrofaom in the body directly underneath.

The dimensions of the top of the styrofoam block was measured and three pieces of 1/16th ply were cut, two of these were to be glued together for strength. The styrofoam block was trimmed with a sharp scalpel and the height of the three ply pieces added together was removed. A captive nut was fitted to the underneath of the double ply piece and this was altogether glued on top of the styrofoam block the other was glued up into the inside of the hatch so it lined up directly over the styrofoam block with the washer being glued between the ply piece and the styrofoam of the hatch. Once dried the whole in the hatch was extended through the ply plate..

A whole was drilled in doubled ply piece now glued to the styrofoam block the diameter of the bolt that would be used to hold the hatch on. A piece of fuel tube was put over the bolt so the bolt did not have to be tightened right down, this also added some cushioning, stopping you from over-tightening the bolt.This modification proved to be a very sturdy method of keeping the hatch secured during flight, and i think will stand up to the tolls of flying more than the suggested method in the instructions.

Likes
The way the rear of the hatch is secured to the body. This is achieved by overlapping the fins so that the hatch slides under the fins.The built in air cooling system which feeds air in from the beginning of the leading edge through the wing and splits passing air into the main chamber and also on through the motors. Very impressive!Quick and very easy to assemble, took approx 4 hours build time.

Dislikes
The instructions consisted of a sheet of german instructions with pictures and then a seperate sheet with english and french condensed instructions but no pictures, for these the german sheet had to keep being referred to.

The suggested way of holding the hatch on was not clear and looked as if it would only serve a few flights.

Plastic clevices

Insufficient warning of how weak the hinge for the elevons became after consistent moving of the elevons during building.

Comment by Greg on 00000000000000. Rating none

So how does it fly?

Comment by Grot on 00000000000000. Rating 3

Good question. From what I saw it was pretty good although not as agile/fast as the twinjet. Otherwise it flew in typical delta style with good stall carachteristics. Easy to land etc. I'll get tony to put this part online, He must have though he had updated the review by mistake.

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