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        Discussion Conver a balsa stick 40 plus

#1 FireChief4302 Aug 19, 2012 11:04 PM

Conver a balsa stick 40 plus
 
I have a Balsa Stick 40 Plus that i was thinking about switching over to electric. I am interested in the ease of electric over glow. I know the stick 40 has been around forever and I hope its not sacrilege to convert it to electric. I am new to flying so if I get any replys type them slowly and in plain english cause I havent got all the lingo down yet. Thanks for your help.

#2 wizard of odd Aug 20, 2012 12:31 AM

Welcome to RCG!

The Stik is a perennial favourite amongst sport models and will fly well on electric power.

Some things need to be considered:
1. Weight of model ready to fly. Since you have the model already it would be easy to weigh it without the power system installed. The projected weight will determine what power plant will be required. If your model is for instance going to be around 5 pounds, and you want at least a power to weight ratio of 100W/lb, you will be in the market for a 500W+ power system.
Power (Watt)= current (Amp) x Voltage. The battery supplies the voltage to the motor via an ESC, and the motor will draw current depending on the load applied to the motor. The ESC needs to be able to handle the amount of current required (usually specified by the manufacturer), and so does the motor. A rule of thumb is 3W/gram for an average outrunner (though a decent quality motor will be able to perform well above this)- so for 500W power consumption, you will need a motor in the 160-180g weight class at least. Since W=AxV, your required power level can be reached by either lower cell count (voltage) at higher current draw, or higher cell count at lower current draw. Another frequently touted rule of thumb would be IC engine size in cubic inch x 1200, which in the case of a .40 size engine would be 0.40X1200=480W. Online propeller calculators like this one http://www.ecalc.ch/motorcalc_e.htm?ecalc can be handy to get you in the ball park, so to speak.

2. Wing loading. For a model like a Stik, you will probably aiming for a wing loading in the range of 15-18Oz/Sq.ft. If you can work out the wing area of the model, you can determine what a realistic AUW should be for the flight envelope you desire. Refer back to point 1. above. You can for instance have a power system weighing lets say 1lb, producing 500W at a power to weight ratio of 100W/lb, or a power system weighing 2lb, but with the increased weight still only producing 100W/lb (or maybe more), at the expense of a higher wing loading and poorer flying characteristics. You need to take this into consideration when choosing your power system- bigger motors and more cells are not necessarily desirable, unless you plan on flying a very high powered brick! It will still fly like a brick though....

Anyway, you must be tired after reading all that rubbish, so: Not knowing the details of your model, my guess would be a motor of between 200 and 250g, with a kV (r.p.m. per Volt) rating of 650-950, ESC of around 60A, spinning a 12x8-14x7" prop at an Amp draw of around 50A off a 4 or maybe 5 cell Lipo pack.

Hope that helps

Odd

#3 FireChief4302 Aug 20, 2012 01:31 AM

Thanks Odd
 
Thanks for the info. I will reread it several more times in the hopes of understanding some of it. I guess I should have included that it has an OS .40 mounted on it now and has flown well with this engine. Plenty of power.
Thanks

#4 wizard of odd Aug 24, 2012 12:45 AM

FWIW, I did a successful conversion back in the days, using an AXI 4120/18 motor, 60A ESC and 16 big heavy round jugs (Nicad cells) spinning a 14x7" prop. It was a bit of a porker due to the heavy batteries, but flew well. A similar spec motor and 5 Series Lipo should do much better due to the weight saving of Lipo vs. Nicad cells.

I believe there's an Eflite 46 motor of similar specs....

Odd

#5 jim e Aug 24, 2012 05:25 PM

conversion
 
2 Attachment(s)
Couple of years ago i built my third BUSA stick for electric power. Just deleted the pics of build which involved some lightening but that is not necessary, I have used a headsup r/c .40 and .46 outrunners on 4 & 5 cell lipolys. Servos are in the wing (2) and in front of the tail feathers. Programmed in flaperons as well. Pics jim

I reckon you can do better in appearance than i did !!

#6 Henry Sistrunk Aug 24, 2012 06:54 PM

I have a number of sticks but am not familiar with a stick plus. All of mine are converted to electric.

#7 FireChief4302 Aug 25, 2012 01:41 AM

Thanks guys. This will help me get started.Looking forward to switching it over. Thanks for the pictures too.


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