Micro-jet owner for EDF experiment.

[Babylon5]

Hi,to all owner of microjet from multiplex.
Looking for a use Micro jet plane with reasonable condition or even reparable condition to be modified for EDF experiment.
If you have this plane that is bash up (not in tiny litle itsy bits) but repairable
please let me know. Quote me a price .


Please PM me if you are tired of this plane.

Babylon5.

[Babylon5]

Micro-jet to edf conversion

Hi- all, manage to get a China made micro-jet. Have converted to a 55mmedf and maiden sucessfully two weeks ago .


First flight with a 3.8KV China motor oK.
Very Fast and very aerobatic. From the vertical performance Thrust to weight ratio is greater than1.
Second flight, just about to hand launch, blade disintegrage. Motor was too powerful.

Downgrade to Tahmazo 3.7KV motor. Have made about 7 flight without problem.

A word of caution . Do not attempt OMO handlaunch! Try this and broke the nose during this attempt. Advise to use bungee or an experience person to hand launch.



Specification:
300 mm wing span(24 inches)
3 cell lipo 2200maH 10C
Motor= Tahmazo 3.7KV reno class.
Total weight with battery =430grams
Control=Elevon mixing


EDF conversion:
1) Select a suitable EDF from 55mm to 70mm
2) Cut out the tail portion so that the EDF can snug into the tail. Added 1.5mm ply top and bottom for strength

3) Add shim(in this case one 3mm nnut and 0.25mm washer to get the fan align to the tail
4.) Cut the tail skip to size so that it is not to obtrusive and can protect the fan during belly landing.
5.) Place the RX, ESC and battery and balance the c.G as shown.

Control surface settings
1) Elevon= 0.5 to 1mm up at neutral
2) Maximun elevator throw 5 to 6mm up-down(caution- do not give too much throw. This plane is very responsive)
3) Ducted Fan thrust is 0 degree to 1 degree left thrust when view from the tail end.

[Justrc]

Hi Babylon5

Can I know from which LHS you got the mirco jet from and how much it cost.

Thks

[Babylon5]

EDF Micro jet conversion


Dear JUSTRC,
To the best of my knowledge , cannot find this in any LHS yet.
A friend brought in from China for me to experiment if it can be use for EDF.
The closes is NTC from multiplex cost over 100 bucks.
This plane original design for pusher speed 400 motor


Cheers
Babylon5

[AceViperX]

Hi babylon,

Where in China did he get it from? Is it within any of the major cities eg. Beijing or Shanghai?

[Justrc]

Dear JUSTRC,
To the best of my knowledge , cannot find this in any LHS yet.
A friend brought in from China for me to experiment if it can be use for EDF.
The closes is NTC from multiplex cost over 100 bucks.
This plane original design for pusher speed 400 motor


Cheers
Babylon5

Thks for the info

[$h@d0w]

Hobby Lobby is having a sale, with the Micro Jet at US$29 excluding postage.

[fuse]

buy buy buy

[kenshinz]

anyone has any idea how much the shipping cost?

[$h@d0w]

buy buy buy

[Babylon5]

Micro-Jet EDF conversion II

Hi , I have conveted another micro-jet using the 68mm EDF from SFM.
This is a hot setup:-
1) Motor= Align430BL-3.55KV
2) 3cells lipo 10C
3) 40 amps ESC
4) 68-70mm EDF from SFM(6 blade black)

Total flying weight=480grams

Max current =23-24amps
rpm=28620rpm at 23 amps( measure using frequency timing method)

Attached is a couple of pictures of the micro-jet and the method to measure the motor rpm with the EDF.

Estimated thrust above 550grams.

Control throws and C.G is the same as the earlier setup with the 55mmEDF.


Advise:
Use a stronger and better servos
Balance the C.G properly.
Use Bungee or an experience person to hand launch.


Flying: Plane flew sucessfully but have to cut down power most of the time to manage the flight properly.
Sorry guys no videos during the maiden because no cameraman available. Next time maybe.

Heh Heh


Babylon5

[jon-AMIG]

Hey Babylon5, care to explain how did you use the frequency method to measure rpm? Its aure a big help to those including me who doesnt have a tachometer. Thanks!

[Babylon5]

Measuring rpm

Hi, this method is only indicative and may not work with all motors or ESC.
It will not work if your setup do not draw enough amps.
In addition some ESC freq may not reflect actual rpm.
You have to try out.

Setup
1) Tower pro 40 amps ESC
2) 3 cells lipo 10C 2200maH
3) Motor tested 2 pole Walkera 380S, 380M
4) Align motor 430BL-3.55KV(6 pole)
5) Align motor 420BL-3.3KV( 8pole-educated guess)
6) Kyoritsu meter with clamp on current and frequency feature
7) Select the meter to "Freq" or "HZ"
8) 68mm EDF from SFM

Method:
1) Determine the number of poles of your motor from data sheet
example 2 poles
2) Determine the pole factor=number of poles of motor/2poles
3) Clamp the meter to any of the 3 wires exiting from the motor.(See my previous posting and pictures)
4) Read the frequency
5) Rpm=(frequencyx60)/pole factor

Example1
Align 430BL-3.55KV is 6 pole
Pole factor=6/2=3
readings=1431hz
rpm=1431x60/3=28620
Measure the DC current =23Amps

P.S. go to www.align.com.tw and check the rpm of the motor of 430BL 3.55KV under load at around 23amps(nearest is 22amps ,11.1V just over 30,000rpm)
Align explain the actual rpm could be lower by 90-95% due to actual LIPO cells discharge condition.
The actual loaded rpm will be close to 27000 to 28000rpm according to Align website ...result quite agree to the result in example 1
info.

Example2
Walkera motor is a 2 pole
Pole factor=1
readings=488hz
rpm=488x60=28980rpm

Warning: Please do not test your motor without proper loading. You could damage the ball bearings if the motor is unloaded at high rev.

I hope this will help.


babylon5

[Crabby]

Hi hi which part of China u got it from? I may go in search for one when I go there next time. An address would be useful and the cost too ")

[Babylon5]

Micro Jet from China

Hi Crabby, I don't know where my friend in China got the plane but
I saw this plane at www.himodel.com

Visit the site and search for the plane.

You can email to Himodel for query. They response very fast.

Cheers
Babylon5