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Using ESC and BEC for the first time.

PostPosted: Sun Jun 20, 2010 4:03 am
by Rob2160
Hi,

I have recently returned to the hobby after a 15 year break and am about to fly a Starmax F-18 Ducted fan..

http://starmax-rc.en.alibaba.com/product/316342588-200767427/RC_airplanes_F_18E_64mm_blue_angel.html

The specs are as follows...

Radio System:4Ch Tx and 6ChRx
Five 9gram servos
64mm Ducted fan
Brushless motor and 30A ESC,
Battery:3Cell Li-Po Battery,
1300mAh,11.1V

Here is a video on youtube of the plane.. http://www.youtube.com/watch?v=-OGhAW8zMkQ

The radio that came with the plane looks cheap and nasty, it is 36 Mhz FM.. with the receiver powered by the primary Li-Po battery (ie no seperate receiver power)

I also have a brand new Spektrum DX6i and a Brand New Futaba 6EX. I would prefer to use one of these radios in the plane.

(Also because they have dual rates, end point adjustment, expo... etc)

Is it acceptable to power a 2.4ghz reciever from this Li-Po or would I be safer sticking with the original radio that came with the kit? (obviously it would work - just not sure about reliability of 36 Mhz FM)

Sorry if this is basic stuff.. My last plane was built in 1989 and powered by an OS 45 engine, the receiver (Kraft) was powered by a 1000mah Nicad BRICK!

All this electric stuff is totally new to to me... So any advice appreciated...

- as an aside, I plan to try each of the radios, and ground run the Ducted fan until the battery is exhausted to see if the receivers brown out...

All suggestions welcome...

Re: Using ESC and BEC for the first time.

PostPosted: Mon Jun 21, 2010 7:02 am
by siang
Nice plane but does it come with radio?
Have you bought anything thru alibaba site b4? I'm wondering if it's safe/common for public to buy thru their site.
I assume it's safe to just follow the recomended stk electronics, without any external bec.

Re: Using ESC and BEC for the first time.

PostPosted: Mon Jun 21, 2010 9:44 am
by kneedrag
Most ESC's have a BEC built into them. They are generally not the best but should do for that electric setup.

Some good reading on electrics in general is here http://wiki.parkflyers.org.nz/wiki/inde ... ric_Guides

I would not ground test the motor in the ground as the load will be different and not reliably test the endurance and you will get different results flying to what you see on the ground. Rather follow this guide to work out battery usage. Then set the timer on tx to let you know when to come in.

http://www.parkflyers.org.nz/modules/sm ... hp?faqid=5

If you always follow this you will never experience a brownout under normal circumstance, if you do you have pushed things to far anyway and the chances are the ducted fan would not have enough power to fly anyway at this point in time.

Welcome to the joy of electrics. ;-)

Re: Using ESC and BEC for the first time.

PostPosted: Wed Jun 23, 2010 2:28 pm
by Rob2160
Siang, yes this did come with its own radio, it was a 36mhz FM unit, but it looked cheap and nasty.. so I removed it and am using a Futaba 6EX 2.4 ghz.. So far so good.. I purchased the Plane at the local hobby store..

Kneedrag, thanks for your info, I have already done static testing, running the engine until there was no more power to turn the Fan unit, and the radio and servos continued to work fine (I know I'm not supposed to run Li Po that flat but It was just one battery and I bought a few spares that get treated with more respect)

I even tried this test with my spektrum radio and suferred no brownout.. it worked fine even when the lipo would not even turn the Ducted Fan unit at all.

I have since flown the plane about 10 times now without a glitch.. and am loving my return to RC flying and the world of electrics... This simple little electric jet has far more performance than any of the glow planes I used to fly 20 years ago... at a fraction of the cost...