HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 14, 2013, 11:59 AM
Hey Ya'll!! Watch THIS!!
Michael Paxton's Avatar
Nashville TN.
Joined Mar 2006
2,555 Posts
As someone said recently: "We are hobbyists! Use something out of the back seat of your car"!

Option "B": Test with plastic paper clip and move on!
Michael Paxton is offline Find More Posts by Michael Paxton
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 14, 2013, 12:38 PM
Lee Liddle
Knife Liddle's Avatar
Carrollton, Tx
Joined Dec 2006
7,877 Posts
There is a slight magnetic pull on the outside of the bell, but since I have full coverage inside the bell Im not surprised. The motor has extremely strong cogging, way more than stock, so I'm not concerned about a little lost magnetic field.


So first the magnets are going to fly out thru the bell, now they aren't going to work well because they aren't 100% efficient.

I'll tell you what. I'll bet that before the end of 2014 that some manufacturer will produce a 12t4p 36mm motor for EDF. It will have almost full mag coverage inside the bell and will be wound with an AABBCCAABBCC pattern. A 28mm would be a good idea too. I just don't need one right now.
Knife Liddle is offline Find More Posts by Knife Liddle
RCG Plus Member
Old Jan 14, 2013, 01:18 PM
Registered User
Joined Jan 2005
2,216 Posts
"the efficiency is less than it could be"

Since were dealing with ducted fans - efficiency is going to be less than it could be anyway. Id be interested to see how much improvement could be had with more metal in the can. I knew there was a reason I bought a lathe.
Air Head is online now Find More Posts by Air Head
Reply With Quote
Old Jan 14, 2013, 01:35 PM
Registered User
firehawkzach's Avatar
United States, TX, Fort Worth
Joined Jan 2011
1,143 Posts
Quote:
Originally Posted by Knife Liddle View Post
Thanks bud, I`ll do my best.

My particular target is somewhere around 55k to 60k rpm on my 3" Haoye rotor cut down to 2.75" (70mm). That will probably yield 8lbs of thrust and near 350mph efflux, but will take 5kw or so.

I want to be able to use the YEG clone 120A HV esc which is good up to about 6kw, but can`t turn the 8 pole motor faster than about 50k, so that`s why I`m switching to the 4pole.

Long term, I`m thinking of a twin laid out similar to the twin engine business jets, but built mainly for speed. 16lbs of thrust at 350 mph has huge potential to be able to hit 250mph in level flight and to be able to carry plenty of mah capacity for decent flight times.
8lbs of thrust out of a 70mm would be revolutionary if you end up building a jet for this please keep me in the loop as I will drive to watch it fly since you aren't too far away.
firehawkzach is offline Find More Posts by firehawkzach
Reply With Quote
Old Jan 14, 2013, 01:55 PM
Lee Liddle
Knife Liddle's Avatar
Carrollton, Tx
Joined Dec 2006
7,877 Posts
Quote:
Originally Posted by firehawkzach View Post
8lbs of thrust out of a 70mm would be revolutionary if you end up building a jet for this please keep me in the loop as I will drive to watch it fly since you aren't too far away.
Will do. I have a jet now that will carry the fan and needed lipos, so when I get it built, I plan to get it in the air. The jet isn`t necessarily a speed effort, more of a sport jet, but it will be interesting to see what 1 to 1 thrust to weight would do when you add in 350mph efflux.
Knife Liddle is offline Find More Posts by Knife Liddle
RCG Plus Member
Old Jan 14, 2013, 03:08 PM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
951 Posts
Quote:
Originally Posted by Knife Liddle View Post
So first the magnets are going to fly out thru the bell, now they aren't going to work well because they aren't 100% efficient.
Just trying to help out and share opinions/ideas. I don't think anyone wants to see your project fail! So definitely don't be discouraged.
SlowBarless is online now Find More Posts by SlowBarless
RCG Plus Member
Latest blog entry: Carbon Fiber up close
Reply With Quote
Old Jan 14, 2013, 03:08 PM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,338 Posts
Cogging or a lack of really has little bearing on the strength of the magnets and more to do with the poles aligning with stator teeth along with their shape. Wasted flux means that you are not taking full advantage of properties of the magnets--which in turn means the motor has to have more turns of wire than it otherwise could have had to get a given Kv resulting in higher resistance.

It is interesting to see how little concern for actual design and engineering--seems much more like a "hold my beer and watch this" attitude. Enjoy!

Steve Neu
sneu is offline Find More Posts by sneu
Reply With Quote
Old Jan 14, 2013, 03:11 PM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,338 Posts
Quote:
Originally Posted by Air Head View Post
Since were dealing with ducted fans - efficiency is going to be less than it could be anyway. Id be interested to see how much improvement could be had with more metal in the can. I knew there was a reason I bought a lathe.
Start here --it is a free program for motor magnetic design:http://www.femm.info/wiki/HomePage

Steve Neu
sneu is offline Find More Posts by sneu
Reply With Quote
Old Jan 14, 2013, 03:20 PM
Registered User
Joined Jan 2005
2,216 Posts
Thanks Steve

Ill grab a beer and start reading
Air Head is online now Find More Posts by Air Head
Reply With Quote
Old Jan 14, 2013, 03:32 PM
Lee Liddle
Knife Liddle's Avatar
Carrollton, Tx
Joined Dec 2006
7,877 Posts
Well Steve if I had a motor factory at my disposal I might be more interested, but since I don't I'll just make due with what I have. If I'm mildly successful, then maybe a real motor builder will pick up the basic design and build it right

I'll bet if I had posted the pics and the winding pattern before I tried it, I would have been told by several knowledgeable, well meaning individuals that it wouldn't even run. But it does, and very smoothly too.

Next step is to put it in one of my fans that aren't designed right and see what it won't do.
Knife Liddle is offline Find More Posts by Knife Liddle
RCG Plus Member
Old Jan 14, 2013, 03:45 PM
Gorilla Glue Expert
PikeStaff's Avatar
United States, PA, Doylestown
Joined Sep 2010
2,667 Posts


Make sure to have a beer in hand.
PikeStaff is offline Find More Posts by PikeStaff
Reply With Quote
Old Jan 14, 2013, 03:48 PM
Registered User
sneu's Avatar
United States, CA, San Diego
Joined Dec 1999
7,338 Posts
Quote:
Originally Posted by Knife Liddle View Post
I'll bet if I had posted the pics and the winding pattern before I tried it, I would have been told by several knowledgeable, well meaning individuals that it wouldn't even run. But it does, and very smoothly too.
12 slot 4 pole motors are rather standard stuff--no reason why it should not run.


Steve
sneu is offline Find More Posts by sneu
Reply With Quote
Old Jan 17, 2013, 12:19 PM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,297 Posts
Moulded ships powered by Neu motors and Stumax fans are way out of my modelling budget. I'm more of a scratchbuilt, Haoye and rewound outrunner sort of guy.

However, I'm willing to accept that my models might be a bit heavier and flights might be a bit shorter than optimum. Tinkering and getting these things to work on a budget has a fascination all of it's own.

So keep on tinkering Lee.

Steve
stegla is offline Find More Posts by stegla
Reply With Quote
Old Jan 17, 2013, 12:56 PM
Lee Liddle
Knife Liddle's Avatar
Carrollton, Tx
Joined Dec 2006
7,877 Posts
Quote:
Originally Posted by stegla View Post
Moulded ships powered by Neu motors and Stumax fans are way out of my modelling budget. I'm more of a scratchbuilt, Haoye and rewound outrunner sort of guy.

However, I'm willing to accept that my models might be a bit heavier and flights might be a bit shorter than optimum. Tinkering and getting these things to work on a budget has a fascination all of it's own.

So keep on tinkering Lee.

Steve
Thanks Steve, oh yeah, I'll stop tinkering when they plant me. Got a new 3126-1600 in the mail the other day. First thing I did was tear it down and rewind- it. It is 14.5t of #22. KV is 1150. Ran it this morning with my YEP-120 on 14s at 66k rpm. No probs. This weekend I plan to get it in a fan and get some vid and numbers. Stay tuned. There will be no esc imposed power limit on this one.
Knife Liddle is offline Find More Posts by Knife Liddle
RCG Plus Member
Old Jan 17, 2013, 02:42 PM
Hey Ya'll!! Watch THIS!!
Michael Paxton's Avatar
Nashville TN.
Joined Mar 2006
2,555 Posts
It's going to be interesting to see how it reacts when a load is placed on it. I think that will tell a lot about whether it will truly work or not.
Michael Paxton is offline Find More Posts by Michael Paxton
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold 64mm edf w/motor 2-70mm edf's, 70mm edf motor Dave Barrow Aircraft - Electric - Jets (FS/W) 0 Aug 10, 2012 07:58 PM
Discussion Game Change mortato Life, The Universe, and Politics 0 Apr 17, 2012 02:31 AM
Mini-Review 64mm SF Shroud, 64mm RClander rotor, and HET 2W-20 motor zach_dad Electric Ducted Fan Jet Talk 2 Jun 12, 2010 10:04 AM