After crossing the T,doting the I and grouting the tiles,it was now finally,time to make my batteries.
I am using the word "make" because,i am going to build a battery from a combination of batterries.
I will have to do so because i those are the only batteries i could lay my hands on at the moment.

So at the moment,i have 4 lipo batteries,rated at 1800Mah 3.6v. I am using two of these to power my Tx. So that leaves me with 2 lipo cell.
On the other note,i have a couple of li-ion cell. About 4 of them,with a rating of 2200Mah 3.6v.
I needed to make a 12v battery for my airplane from a combination of those aforementioned cells,owing to their high power to weight ratio.
So here is what i did.
But before i proceed,i would like to caution any one attempting to do this.
PLEASE DO NOT CONNECT BATTERIES OF DIFFERENT CAPACITY IN SERIES.
Don't try this at home or in a lab,not unless you have a good knowledge of lipos and li ion batteries.

Below are the cell. The lipo are the white cell. The li-ion are the cells that looks like a normal finger battery,nickad or Nimh batteries in the picture.

Those li-ion cells were gotten from a laptop battery. In the pix above,i paralled the li-ion two,two to give a capacity of 4400Mah.
So with two 4400Mah li-ion cell,and one 3600Mah lipo. I can make a 12v battery bank by connecting the lipo and li-ion in series. Charging them would be done one by one and separately,with a power source charging each one with 4.2v. They can never be charged as a bunch at once,with a 12v power source as a charger..

You can email me on kingsleyobinna26@yahoo.com if you have a personal enquiry.

I starte by soldering a wire from the negative terminal of the lipo,to the postive terminal of the li-ion cell.

Then i soldered a wire from the negative terminal of the first stack of li-ion cell,to the positive terminal of the second stack of li-ion cell.
Therein after which i then soldered a black wire for the main negative wire. The red wire is the main positive wire.

A view of the side of a soldered end

Here's my programable lipo charger .

After all,i made a go at the batteries by charging them. I charged them separately,and waited untill the third cell was charged to the full,then i got set to do a taxi run test.

Here's the airplane awaiting its first test run.

Pakingzzz:
Here's the airplane awaiting its first test run.

Ive been following your thread.
First of all, NICE WORK.
From my thesis, i dont think it will fly well, cause of the width. I think you need a thin material.
Just contributing
Good work

Pakingzzz:
Here's the airplane awaiting its first test run.

still following, how long does it takes to charge your batteries full ?

zeanslim:


still following, how long does it takes to charge your batteries full ?

.Around 50mins.

redfigure:

Ive been following your thread.
First of all, NICE WORK.
From my thesis, i dont think it will fly well, cause of the width. I think you need a thin material.
Just contributing
Good work

The width aint that much. Besides i've rounded the leading edges and tappered the trailing edges with a sandpaper. So the wing has an airfoil profile currently. I shall post pictures of it.

I did a taxi test run,to see the thrust of the propeller.
I noticed the thrust wasnt enough for a 1kg airplane. So back home i went.

I went back to work. I decided to build another propeller out of aluminum. It measured 7" from tip to tip. I then gave it an angle of 20 degrees towards the hub,and 10 degrees towards the tip.
After other itineries,i spun the prop. It spun up nicely without much need for balancing,owing to the fact that i was precise with my calculations and cutting.
Next,i hooked it on my airplane for a thrust test.
This time,the result was reassuring but still not enough for the 1kg craft. More importantly was the fact that the brushless motor felt very hot. This was an indication that the prop was imposing alot of load on the motor. This baffled me because i had a 120watt brushless motor,and it ought to furnish me with enough power to fly my craft. But it didnt instead it ran hot. I had a feeling there were a great deal of inefficiencies in the system.
I left it at that stage,and went ahead to do a little research.

After my research,i came to realize that i was running my prop at too great a speed,and it wasn't efficient at that speed,instead it was a hell of a load to the motor,and was causing a near stall,that was why my motor ran hot. Needful to say that,my motor has a kv rating of 3800kv. Which is to say that,at 1 volt,it rotates at 3800rpm. At 2 volts it rotates at 3800 times 2,and so on. So at 12 volt,it rotates at 45,600rpm. That's too great a speed for a prop. The tip speed of the prop would be exceeding the speed of sound (mach 1) at that rpm.
So i needed some sort of gearbox to step the speed down.

Pakingzzz:
After my research,i came to realize that i was running my prop at too great a speed,and it wasn't efficient at that speed,instead it was a hell of a load to the motor,and was causing a near stall,that was why my motor ran hot. Needful to say that,my motor has a kv rating of 3800kv. Which is to say that,at 1 volt,it rotates at 3800rpm. At 2 volts it rotates at 3800 times 2,and so on. So at 12 volt,it rotates at 45,600rpm. That's too great a speed for a prop. The tip speed of the prop would be exceeding the speed of sound (mach 1) at that rpm.
So i needed some sort of gearbox to step the speed down.

Great work bro. I'm following you

I proceeded to build the step down gear.
I used a gear i got from a standing fan.
This gear has 60 tooth,and the pinion gear on my motor has 13 tooth. That is a ratio of 4.6.
So with a 3800kv motor,rotating at around 45,600Rpm,the gear shaft which is my propeller shaft will be rotating at 9,913Rpm,that's decent for me.

After finishing the build,i tested it by spining the setup at high throttle. A little noise indicated tight gears meshing,and the need for some clearance between them.
I gave it a little clearance,and spun it up once more. The sound was gone.

Next,i installed my scratchbuilt aluminum propeller. Spun it up,and the thrust was awesome,or so i thought.
Then i went for a thrust test in a nearby field.
Although i was happy at the thrust,i was still a bit hungry for more propeller power,and was dismayed somewhat.

I went back to work.. After tearing the propeller apart,i installed a plastic propeller i had had sometime,on to the aluminum prop,thus making a four bladed propeller.
Meanwhile,on my previous test with the aluminum prop,i had noticed that the motor didnt get warm at full throttle,thus ruling out any fact that the prop was overloading the motor,and giving a strong indication that more prop could be attached. This was why i went ahead to make the prop four bladed.

After the modification,i spun up the setup. It wasn't bad..
I would know if it was bad,after a thrust test. So out to the field i went.

The result was awesome. The thrust was much that the airplane lifted about half a foot off the ground. Unprepared for a maiden(first flight of an aircraft),i brought down the throttle and the airplane landed hard on the ground. I had a friend to video the scene. It was done with a high resolution camera,eventualy the size is too large. I can't afford to upload a video of such size. so i want to convert it to mobile mp4 and 3gp. I shall upload it soon.

For now,i am becoming good on the simulator.
The simulator i am using is Fms. It is a freeware stuff,you can download it @ www.Modelsimulator.Com

Below is a pix of my reduction gearbox.

The gearbox installed into the nacelle.

The wing of my airplane was modified to have ailerons and flaps seperately. I used one servo for each. The servos are mounted inside the body of the airplane,and control rods are used to transmit the movements to the ailerons and the flaps.

Here's the modified airplane..

Pakingzzz:
The gearbox installed into the nacelle.

you are toooooooooooooooooooooo much

whaooooooo....happy to follow this topic

Parkingzz, I don't understand why you are making your own propellers, since home-made props are bound to be so much harder to balance to prevent vibration. Just looking at that METAL 4-blade propeller on your plane, I will venture to say that the bird will NEVER fly with that heavy, clearly unbalanced propeller concept. Go with factory bought propellers, and save yourself a whole ton of pointless "busy work".

Same thing for batteries. If you are ordering lipo battery cells, then why not just order pre-assembled batteries from Hobby King ? In constructing air-frame from scratch, you have demonstrated great skill RC plane fabrication, BUT, you will progress so much faster if you buy your batteries, propellers, ESCs and such assembled and ready to go.


The amount of trimming and sanding to balance a factory manufactured propeller will be significantly less than the time and effort it will take to balance that home-made 4-blade propeller you have made. My hat is off to you brother, but I think you can really speed up your progress by avoiding any tasks that are akin to re-inventing the wheel.