Need recommendation for brushless conversion
 

Hi All,
I have a Kyosho Cessna 180 that I would like to convert to brushless and lipo for as cheap as possible (ie. HobbyCity) while still maintaining some quality (won't die on me after 5 flights). Here is the link:

[link=http://www.rcuniverse.com/product_g....cfm?kit_id=299]http://www.rcuniverse.com/product_g....cfm?kit_id=299[/link]

I'm an experienced glow/gas flyer, but this is my first electric. I've done a ton of research on selecting power systems, but it seems like every manufacturer has their own naming schemas. Could someone suggest a cheap power system for me from HobbyCity?

Ideally, I'd like plenty of power while keeping things very light for slow flying characteristics at a park. Ie. When i hit the power it will climb to no end, but when i kill the power, it will float and fly slow like a Cessna 180 should (very low stall speed).

Here is some more information:
Weight w/ current brushed motor (haven't taken it off yet), brushed esc, and servos (no battery): 2 lbs (I would guess the brushed motor weighs about 8oz - it's a mabuchi 550)

Wingspan: 51' x 9' = 459 sq/in wing area

Thanks in advance!

RE: Need recommendation for brushless conversion
 

Just a wild guess here... but this is what i came up with:

Turnigy 35-30 1100kv Brushless Outrunner motor
Turnigy Plush 30A ESC
Turnigy 1600mah 3S 20C Lipo pack

How does that sound for this model? Too much? Not enough? Insane?

It would cost me around $60 shipped.

RE: Need recommendation for brushless conversion
 

I would say you made a good choice. Based on your figures, you should achieve excellent flight performance running about 20 amps on a 10x5 prop. Efficiency at this level is about 80 percent according to Eagletree data. Your plane should be much lighter using a brushless motor and lipo, so your performance might be even better than predicted.

Your plane should easily handle a 2500 mAh lipo which would more easily supply the continuous 20 amps at full throttle, and the extra weight might be needed to obtain the correct CG. Also, you would only be drawing about 10C at full throttle which should enhance battery longevity and give you significantly longer flight duration.

RE: Need recommendation for brushless conversion
 

THANKS Whitecrest! That's excellent information. Thank you so much for taking the time to run the numbers and figure that out for me. Very helpful!

RE: Need recommendation for brushless conversion
 

My pleasure. WeboCalc is a great calculator and a lot of fun to play with. Here's a review you might find interesting:

[link]http://www.rcgroups.com/forums/showthread.php?t=385580[/link]

This plane was evidently around before brushless motors and lipos became popular. It is interesting to see how they boosted it's power in 2001.

Good luck with the setup!

RE: Need recommendation for brushless conversion
 

WebOCalc discussion, help, announcements:
http://www.rcgroups.com/forums/showthread.php?t=930018

Compilation of e-flight calculators, including WebOCalc:
http://www.rcgroups.com/forums/showthread.php?t=606703

Vriendelijke groeten ;) Ron

RE: Need recommendation for brushless conversion
 

Sorry, i've confused myself now. I've found 2 motors that have relatively the same Kv, but one uses more wattage than the other. What's the difference between these? Should i only be looking at Kv, or more?

http://www.hobbypartz.com/alpha-3701...ess-motor.html

http://www.hobbypartz.com/alpha-4801...ess-motor.html

The motor that is on it now is a 550 Mabuchi. So should i go with the 480? Jeez... why are electrics so confusing. There are 1 gazillion figures to learn.

RE: Need recommendation for brushless conversion
 

Kv only tells you how fast a motor wants to run at a certain voltage. rpm = Kv x voltage. Kv says nothing about power, current or torque.
You choose prop and rpm for your plane, you choose battery. From that you choose Kv. You calculate current.

Watts are not a good indication for a motor, you need to know the maximum current, it's the current that can kill.
Get/buy a current/Watt-meter, it will save you money!

Choosing a power setup
http://www.rcgroups.com/forums/showthread.php?t=739069
http://www.wattflyer.com/forums/showthread.php?t=27019

E-book: Everything You Wanted To Know About Electric Powered Flight
http://homepage.mac.com/kmyersefo/ev...ng-e-power.pdf
Corresponding discussion:
http://www.wattflyer.com/forums/showthread.php?t=31071

Vriendelijke groeten ;) Ron






Vriendelijke groeten ;) Ron

RE: Need recommendation for brushless conversion
 

Ah ok. That makes sense. Thanks Ron.

So for my setup above, the engine says "Max. efficiency current : 10~15A". Do you think that's enough for this plane? Or should i go with something that uses more current, like the alpha 480: http://www.hobbypartz.com/alpha-4801...ess-motor.html