Multiplex Twinjet becomes MonoJet and flies MUCH better with less power needed !!!

 

Conversion to a single motor is extremely easy. The motor & esc are in direct line with the central fuselage. So no long wires or tunnels needed. It can be clearly seen in the construction photos.

Batteries
8-10 cells.

tj_mono_1tj_mono_2

Motor
kontronik 501 packages. It consists of the fun 480-33 motor with a 4.2 gearbox.

tj_mono_3tj_mono_4

Possible Motor combinations for the Monojet

Note: "good" - our reference point. "good" is the way the Monojet flies with the kontronik 501, 8x1700CP, 11x12.75 prop. performance can be seen in the video. naturally, "good" is much better than the regular stock Twinjet...

 

Propeller
I tried several folders. It must be folders to prevent prop breaking every landing.

The basic prop is a 11x10 (Aeronaut), this is the highest pitched prop I could find. I added a "twisted yoke" with 2.5 degrees and it became 11x11.4.
2 videos taken with this setup and 8 and 10 cells.

Then, I tried 5 degrees "twisted yoke" which made it a 11x12.5.
This one gave the best performance even with "only" 8 cells. It has an amazing climb ability and excellent speed.2 Videos taken with this setup

tj_mono_5tj_mono_7tj_mono_6

Power consumption

This power set-up draws about 27 amp (motocalc predicts 28 amp - good work motocalc !! ).

Flight Test results

I did not try this arrangement with 10 cells yet, but it should be a beast!! 8x1700CP produce amazing performance.

I was a little worried before the test flight because of two things: torque roll right after hand launch & injuring the arm by the large centered prop. I was worried for nothing. The prop stays away quite a bit from the launcher arm, so no problem here. Even with all the torque, I only needed 2-3 clicks of right trim to make it fly straight as an arrow!

The Monojet has a different sound than the original/twin-powered set-ups, less noisy, a lower sound.

Climb out at 60 degrees forever with excellent speed. With 10 cells it should go vertical with amazing speed and still only draw around 36amp. Landings are easy (like in all twinjets) with the large blades folding neatly at touchdown. One thing in flight is different and that is the rolls. If you think twinjet's rolls are fast, you must check out the Monojet's rolls, about twice as fast (due to the centered prop I suppose). It was a pleasant surprise.

 

We tested the Monojet side by side with Patrick's brushless Twinjet (kontronik twin drive), both planes operated by 8x1700CP. Monojet was a little faster and had a better rate of climb (watch the video of this test).

 

Feel free to contact me with any questions regarding building or anything else. Most important, if you need any advice in choosing a suitable power set-up, I can help here as I became a real "motocalc expert" in these Monojet different power systems.

My Email: odedmaz@inter.net.il 

Ezone related Review

 
Oded Mazor and his Multiplex "Mono
Jet"

Videos
See videos of the test flights with the 2 different prop setup here