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Nov 22, 2016, 07:26 PM
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Thread OP
Discussion

1980 "My-O-My" Convert to electric questions...


I could sure use some advice from those of you experienced with electric systems.

I have been out of the hobby for about 25 years and would like to get back into it. I've been to the local flying field a couple of times recently - wow! No frequency board and practically everyone is flying electric - I love it!

I enjoy scratch building and would like assistance/advice on converting an old "nitro" plane design to electric. I used the online calculator "Webocalc" to determine the power needs, and I've been reading as many conversion stories as I can find and my head is spinning!

Here is the Airplane I plan to build...

"My-O-My"
http://www.outerzone.co.uk/plan_details.asp?ID=5768
parasol wing
throttle, rudder, elevator
Wingspan 54 inches
Wing Chord 10.5 inches
Total Wing Area 560 square inches
Wing Dihedral 2.5 inches each tip
Weight Ready to Fly: 54 ounces
Wing Loading 13.9 ounces/square foot
recommended engine size .15-.25

QUESTION #1: How do these component selections sound to you? What would you suggest different?

Motor
Eflite Power 25 BL Outrunner Motor, 870Kv - $69.99
EFLM4025A
"Equivalent to a 25-size glow engine for sport and scale airplanes weighing 35.5 lb"
"Needed To Complete: 4045A brushless ESC"

ESC
Hitec Energy Sport 50A, BL ESC - $39.99

QUESTION #2: what will the $75 CC Phoenix Edge give me that the $40 Hitec won't?

Battery
Eflite 3200mAh 3S 11.1V 20C LiPo, 13AWG: EC3 (EFLB32003S)
$44.99

QUESTION #3: It seems that e-motors are shorter than nitro. Can I or should I modify the build to move the firewall forward, with the added benefit of allowing me to move the battery forward?

Thank you to anyone willing to read through yet another plea for help and offer your advice. I'm sure there are about 100 questions that I don't even know I should be asking yet.

David
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Nov 22, 2016, 08:37 PM
Registered User
aymodeler's Avatar
1) That motor combo should give you plenty of power and should work well.

2) The Hitec ESC should be fine. The Phoenix are top quality and I do like them for high power applications, but in your application I would not hesitate to use something like the Hitec.

3) Yup, you will need to modify the mount when converting a nitro design to electric. There are MANY different approaches to this. My personal favorite is to use thick wall aluminum tubing to make standoffs. Just be sure to make all the standoffs equal length so as not to mess up the thrust angle.

Be sure you mount your ESC and battery where there will be plenty of cooling airflow. If you mount them behind the firewall, add some holes to in the firewall and open up a section of covering near the bottom of the tail to allow airfowl
Nov 23, 2016, 04:10 AM
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scirocco's Avatar
Without specifying prop size, there can be no realistic assessment of a set of components.
Unless you can fit at least a 10" prop that motor and battery combination will be unsuitable for a 3.5-4lb model. 10" props should give you 60-70 Watts /lb which will be enough for relaxed flying. 11" would provide a bit more margin and 12" would give you heaps of power.
If you are planning on more gentle flying with peak power under 300W then a 3200mAh pack is bigger and heavier than you'd need for 7-8 min flights. You could get away with a 2200, save weight, need less power, fly longer on the same energy.

On the flip side, that motor will also do well in heavier models on 3 and 4s so a pretty versatile choice.
Nov 23, 2016, 01:52 PM
Registered User
Thread OP

Thank you


aymodeler: Thank you for your quick reply and for the great info. Especially the photo - makes it crystal clear.

scirocco: Great point about the 3200 mAh battery being more than required for gentle flying, which this pilot & plane are likely to be doing. Regarding prop selection, "Webocalc" indicates a 12x8 APC-TE (I couldn't find that prop on the APC website, but I will investigate which 12x8 to use later.) The 12" prop leaves about 1-1/4" clearance to the ground with the tail up and level with the ground.

Thanks again to the both of you for your quick and thoughtful responses. I hope to gather materials and components and begin the build in a week or so.

Happy Thanksgiving,
David
Nov 24, 2016, 02:49 AM
DFS#000178
Rampage's Avatar
Another option for motor mounting--and one that I like a lot--are the Great Planes adjustable mounts.

They're a tad bit on the heavy side, but they're great for electric conversions because they generally match the mounting holes for glow engine mounts so you don't have to tear up the existing firewall with new holes and blind nuts and all that. And they're adjustable in both motor position and thrust angle.

They're really neat. I've used both the 'small' and 'medium' mounts and they worked great.
Nov 25, 2016, 10:30 AM
I am a nice guy! Really!
Quote:
Originally Posted by Rideguy
. . . "Webocalc" indicates a 12x8 APC-TE (I couldn't find that prop on the APC website, but I will investigate which 12x8 to use later.) . . .

David
The TE stands for Thin Electric. A designation perhaps used by other prop makers or users. They are actually talking about what APC refer to as their "E" type props. The "E" type are designed for use on electric motors. They provide better performance than those intended for glow engines because they can be built lighter since electric does not put as much stress on a prop as a glow engine. The blade shape is also optimized for the lower RPM that electric motors turn compared to glow.
Nov 25, 2016, 08:42 PM
Registered User
Thread OP

Pulled the trigger...


Just ordered the DX6 (with AR610 receiver), the I-flite Power 25, the Hitec 50, and two 5040 servos.

Think I'll visit the local hobby shop tomorrow and buy a bunch of balsa & spruce to start the build!

Thank you all for the fantastic input. It really helps me get going!
David
Nov 26, 2016, 08:03 AM
Registered User
aymodeler's Avatar
Quote:
Originally Posted by Rideguy
Just ordered the DX6 (with AR610 receiver), the I-flite Power 25, the Hitec 50, and two 5040 servos.

Think I'll visit the local hobby shop tomorrow and buy a bunch of balsa & spruce to start the build!

Thank you all for the fantastic input. It really helps me get going!
David
Be sure to post pics and let us all know how it comes out!
Nov 27, 2016, 01:38 PM
Registered User
Thread OP

Will post build ...


Thank you all very much for your responses & support.

I have ordered loads of material as well as the motor, esc, radio, batteries, charger, etc. (ouch!)

I will likely begin the build in a week or so. Is this forum ("Glow to Electric Conversions") the proper one to post the build?

Thanks again,

David
Dec 18, 2016, 07:18 PM
Registered User
Thread OP

I started my build!


Hi again,

I have begun building the My-O-My. I am posting pics and comments in the "Balsa Builders" forum in a thread where others have built the same plane. Here is the start of my posts:

https://www.rcgroups.com/forums/show...ostid=36446795

Thanks again for your help.

David
Dec 18, 2016, 09:54 PM
Registered User
Thread OP

Another question...


I have never had an electric plane nor a 2.4 Ghz radio. Is there any concern with the placement of various components relative to one another? That is, does the receiver need to be away from the battery, the ESC, the servos? Can the receiver antenna be routed near the servos?

I see there are two antennas on the AR 610 receiver. I assume that they need to be arranged orthogonal to each other?

I have attached a jpg showing where I plan to place the components. I plan to extend the fuselage forward about an inch to allow me to use the top hatch to access the battery.

Do you see any issues with my proposed equipment & antenna placement?

Thanks in advance for any comments & suggestions you may offer.

David
Dec 18, 2016, 10:48 PM
Registered User
Looks good.
Rx away from battery is good.
As long as there is airflow for lipo and ESC. Most times just an escape hole at back for air movement is fine.
Dec 19, 2016, 07:09 PM
Registered User
aymodeler's Avatar
Just checked out your build photos on the other thread ... looks like you are off to a great start!

As Jotasol said, the placement of your electronics looks fine.
Jan 04, 2017, 08:56 AM
Isaiah 40:31
rc capo's Avatar
Very cool. Reminds me of a great flyer, the Wayfarer

http://www.outerzone.co.uk/plan_details.asp?ID=5908

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