New Products Flash Sale
Thread Tools
Old Jan 27, 2016, 09:31 AM
Rawberry is offline
Find More Posts by Rawberry
Registered User
Joined Jan 2016
4 Posts
Help!
Question regarding electronic setup [first build]

Hi everyone,

i have a noob question regarding the electronics of my first scratch build and this is also my first post here.

Short introduction: This is Alexander from germany and i'm going to build my first scratch build plane. I never scratch built any rc aircraft and so i did my fair amount of research in this and other forums but now i got some questions that i couldn't answer myself.

I plan on bulding this beginner aircraft from foamboard and in an impulse i already ordered all the electronics from hobbyking. But now I'm wondering if the parts will be able to make this plane fly.
Here are the parts in question:
Motor 250 outrunner 2200kv: https://www.hobbyking.com/hobbyking/...arehouse_.html
ESC 12 amp 2A BEC: https://www.hobbyking.com/hobbyking/...arehouse_.html
Servo 9g: https://www.hobbyking.com/hobbyking/...arehouse_.html x4
Battery 950mah 2s: https://www.hobbyking.com/hobbyking/...arehouse_.html
and also a 6x4 prop.

The finished plane will weigh around 300 g. According to the specs, the motor is designed for planes up to 340g.

Now for the question(s):
1. Will the ESC be sufficient to power the motor and 2-4 9g servos?
2. Will i be able to use a suitable 3s battery in the future with this motor/esc combo? I want to start with the 2s battery and after some practice use a 3s for more speed.

Many thanks in advance, this is really a great forum and i hope to become a part of the community in the future

Greetings,
Rawberry
Rawberry is offline Find More Posts by Rawberry
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 28, 2016, 09:16 AM
redwhskers is offline
Find More Posts by redwhskers
redwhskers
redwhskers's Avatar
United States, NY, East Nassau
Joined Feb 2010
477 Posts
Motor

RB
Motor will not take a 3s battery and 10amp ESC max. Servos and Prop OK.

Build Fly Fix

RW
redwhskers is offline Find More Posts by redwhskers
Reply With Quote
Old Jan 28, 2016, 02:46 PM
Quorneng is offline
Find More Posts by Quorneng
Registered User
Joined Feb 2007
613 Posts
Rawberry
The HK specification for the motor tells you "Max current: 7A " and "Current capacity: 8A/15sec".
So these are the figures that really must not be exceeded.
The actual current drawn will depend on the diameter and pitch of the prop and the battery voltage.
HK also recommend a range of props that would be acceptable on a 2s LiPo.
If you run it on a 3s you would have to use a very small prop to keep within the 7A max continuous limit.
You can see the advantage of a Watt meter so you can measure the current rather than find out by expensive trial and error!
At 300g you plane will be about as heavy as the motor will be comfortable to fly so you don;t want to go very much heavier!
Quorneng is offline Find More Posts by Quorneng
Reply With Quote
Old Jan 28, 2016, 05:04 PM
springer is online now
Find More Posts by springer
treefinder
springer's Avatar
SE MI
Joined Oct 2004
11,888 Posts
Not sure why you like that motor, but a bunch of us have found excellent results with the several 24gram "bluewonder" style motors like this: http://www.hobbyking.com/hobbyking/s...or_1700kv.html
http://www.hobbyking.com/hobbyking/s...er_1700kv.html
http://www.hobbyking.com/hobbyking/s...er_1300kv.html

The first two will fly a 10 oz plane quite nicely on an 850mah 2s pack with a 7x6 apc style prop. We use them for our streamer combat planes (flat out for 5-6 minutes, pulls about 9 amps). Several guys started using 3s packs and switched to the 1300Kv motors like the last one and same prop. Those really scooted.
springer is online now Find More Posts by springer
Reply With Quote
Old Jan 29, 2016, 03:21 AM
Rawberry is offline
Find More Posts by Rawberry
Registered User
Joined Jan 2016
4 Posts
Thank all of you for the provided answers. This is such a great community.

My ordered items will arrive today, but before I'm able to test them i have to finish the plane first and then figure out how the electronics and my transmitter work together. So much to do but luckily it's friday already

@springer: Thanks for the suggested motors. I chose my motor because Flite Test recommended a 250 size 2200 kv motor. But i will order your third suggested motor together with a 3s battery as an upgrade. Do you think the ESC that i already own will handle that upgrade?

Greetings,
Rawberry
Rawberry is offline Find More Posts by Rawberry
Reply With Quote
Old Jan 29, 2016, 08:45 AM
springer is online now
Find More Posts by springer
treefinder
springer's Avatar
SE MI
Joined Oct 2004
11,888 Posts
12 amp should be ok although 18-20 will give better "headroom". This assumes you will be flying mostly at a "cruise" speed of about half throttle, with occasional bursts of full throttle. If you are gonna fly flatout wide open throttle, then go with a higher amp rating. Also if you find the plane wants a larger prop, i would start with a 20 amp. But if you actually use the full capacity, you will need a larger motor. 20 amps through a blu wonder motor will toast it relatively quick. Easy to tell, if the windings get dark, you are running too hot (in both amps and temp). To really understand what's going on a watt meter is a worthwhile investment!

Should also add that staying with a lower size 3s lipo in the 850-1000mah sizes will help. Less weight add than larger packs, and the max current draw will be less than a larger capacity pack.

If you feel the need for more power, my fave stepup motor is the Emax cf2812 1600Kv motor (sometimes shows as 1534Kv) it is usually one of the least expensive ones on HK, but performs well and handles 20+ amps ok. My spitfire (35" span, 17oz auw) flies like a warbird should with that motor, a 7x6 prop, 25-30 amp ESC and 1300mah 3s zippy compact lipo. Click on my username and go to my blog. There is a list of my planes with links to build threads where you can see specs and vids and get a feel of how each package performs.
springer is online now Find More Posts by springer
Last edited by springer; Jan 29, 2016 at 09:05 AM.
Reply With Quote
Old Jan 31, 2016, 03:19 AM
Rawberry is offline
Find More Posts by Rawberry
Registered User
Joined Jan 2016
4 Posts
Hey springer,

thank you so much for this in detail answer.
There are so many possible combinations of motor/ESC/battery/prop that i find it hard to chose.
I will consider your recommendations in my next order.

As of now I'm very happy that I was able to finish building my first plane and that all the electronics work as they should. The total weight is only 201 g as opposed to the 300g I mentioned earlier.
I cant wait to maiden it. Hoping for good weather today.

Greetings,
Rawberry
Rawberry is offline Find More Posts by Rawberry
Reply With Quote
Old Jan 31, 2016, 09:03 AM
springer is online now
Find More Posts by springer
treefinder
springer's Avatar
SE MI
Joined Oct 2004
11,888 Posts
You are certainly welcome, half the fun of the hobby is helping others who are where i was a few years ago (well, maybe only a third: build, fly, help!). You are right that there are a bewildering number of options for power nowadays. My mantra is funperbuck, so i will always be looking for lowest cost options. Cutting weight by a third will do more for performance of your plane than motor options, and puts it right in the sweet spot for a BW motor setup! Congrats! Let us know how she goes and don't forget pix!
springer is online now Find More Posts by springer
Reply With Quote


Thread Tools