Minifunjet scratchbuilt - RC Groups
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Jun 18, 2012, 05:02 PM
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Build Log

Minifunjet scratchbuilt

Hi everybody,

This is my first thread ever on rcgroups.
my English is not so good that is because my origin language is dutch.

the plane is based on the Funjet ultra and radjet420.

I started building this plane one week after I build the radjet420. My intention was to put the 2730 outrunner in the radjet420. But when I received the radjet, he seems smaller than I expected. So I decided to build a bigger one out of depron.
The plane is built out of depron and balsa and is completely covered with oracover.

Wingspan: 20.5"/52cm
Length: 18.1”/46cm with motor and prop.
AUW: 7.8oz/220g (without battery), 12.1oz/342g (with 1300Mah) and 11.4oz/323g (with 1050Mah)
Motor: Brushless outrunner 2730 bluewonder 3000kv 24gram. Rewound after I burnt the original.
original: 10turns 4x0.23mm wires parallel DLRK
rewound: 10turns 6x0.20mm wires parallel DLRK
ESC: Aeolian 40A (same as Turnigy 40A Pentium)
Prop: 4.75x4.75 APC Speed
Lipo: 1300Mah 45-90c Nano-tech or 1050Mah 40c rhino
Receiver: OrangeRx R610 6ch 2.4Ghz Receiver + OrangeRx R100 Satellite
servo’s: 2x E-sky digital servo 7.5g
Speed: 219.6kph / 136.5mph (Fastest measurement with Photomate 778 lite gps).
Power: WOT 30.2A, 16.6oz/490gram thrust (with 1300mah nano-tech lipo and 4.75x4.75 APC)
Mixing: 3% right aileron at full-throttle.
Total cost: 75$ (without transmitter)

Test flight: For the test flight I used the same CG of the radjet420. The setup has enough power to fly straight up right out of the hand to make some height. After 3 rounds of trimming (the plane needed a lot of trimming) the plane flights very well. The CG was a bit too far forward. So I landed the plane and adjusted the CG. The second flight I gave full throttle at the start and went straight up. I made the first large dive and made a low fly by at full throttle. I got an ear to ear grins on my face for the rest of the day. The landing went very well cause I set a switch with 125% dual rate for the ailerons and the elevator.

I am very happy with the result: easy to throw, flies very fast and very slow, makes small turns, the roll-rate is insane and is the plane is easy to land.

In the next days I will post some more building pics and I will make a video. I will also upload the results of the Photomate 778 lite gps.
Last edited by shellsfan; Jun 19, 2012 at 01:22 PM.
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Jun 19, 2012, 08:08 AM
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I first decided which airfoil I should use. I choice for tl56 cause this airfoil is for jet, turbine and aerobatic planes. Then I draw a plan. I cut this airfoil in different sizes out of derpon and balsa and glued them on a 4mm carbon fiber rod. I covered the underside with 2mm depron. After this I made some reinforcements on the edges of the wing and in the area were the ailerons should come. I also installed the servo’s, receiver + satellite and the speed controller inside the wings so I will have enough place inside he fuselage to place the battery.

Jun 19, 2012, 08:45 AM
SG Talon... Super Genius.
Holy Lotta Ribs Batman!!

I bet you could get away with 1/3 that number of ribs and save a lot of cutting!! One of the things i like most about building with foam is it requires a lot less structure to get the shape and strength that you want. Plus less parts means repairs are a lot simpler.

Looks pretty sweet though. Very smart to get all the electronics in before you close it all up.
Jun 20, 2012, 11:09 AM
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Ben D Wing's Avatar
Excellent work!!

Thank you for sharing.
Jun 20, 2012, 04:15 PM
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I covered the upper site with 2mm depron and sanded the edges of the wing.
After that I cut out the ailerons and covered the whole wing with oracover.

Jun 20, 2012, 06:43 PM
Don't look at me like that....
62pilot's Avatar
Awesome work there dude. Keep it up.
Jun 20, 2012, 06:59 PM
My plans are in my blog
Rusty-Gunn's Avatar
Welcome to RC Groups. Your english is very good, no worries. Nice plane.
Jun 21, 2012, 10:29 AM
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Thanks everyone
Jun 22, 2012, 03:51 AM
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The fuselage is made out of 11 layers of 6mm depron glued together and sand them in the right shape. I also cut out the right shape so the fuselage fits over the wing.

Jun 22, 2012, 04:11 AM
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Ben D Wing's Avatar
What do you use to glue your Depron, foam safe Cyano? I guess UHU Por is not ideal because it doesn't sand.
Jun 22, 2012, 09:40 AM
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I use aerosol spray named: 3M Super 77 Multipurpose Adhesive. this is easy to sand.
Jun 22, 2012, 11:54 AM
Registered User
Your building skills are better than your English!
But than again, your building skills are rather extraordinary...

For those who want to learn a bit of Dutch, the correct description of this project is "vetjes"!

Jun 27, 2012, 09:11 AM
Registered User
I just received the APC 4.75x5.5 speed prop. i will try this prop today. mayby i will hit the 150mph.
Jun 27, 2012, 09:32 AM
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Ben D Wing's Avatar
Originally Posted by shellsfan
I just received the APC 4.75x5.5 speed prop. i will try this prop today. mayby i will hit the 150mph.
Good luck!
Jun 27, 2012, 04:05 PM
Registered User
I cut the fuselage in half and used a dremel to hollow the 2 pieces. I also made a motormount out of 2mm carbon. To strengthen the fuselage I used epoxy and carbon fiber roving.

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