HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 11, 2005, 11:18 AM
crashin with a smile
sirdirk007's Avatar
Los Angeles Industry, California, United States
Joined Jul 2004
1,149 Posts
Yippee!
Lets see if you guys can reccomend a motor for this!!

I have a new 55 inch pylon racer with tricycle retractable landing gear and total weight should be around 2lbs ready to fly. I am considering using 2 paralel 2100 3s packs in it. there will be a total of 6 servos.(7 if I use flaperon) This is a gas conversion from a .35 size. I will again be using pico size servos all around.
I am planning on winding my own brushless motor and figured a double min but probably tripple stator. The question is how many winds should I use? What ESC to use? I favor CC ESC's. I am planning on a direct drive and the prop needs only to be a 10-8. It is not a 3der or anything just a fast flying hair on fire pylon racer. I will post pics of the unit complete but I need to finish my other projects first. I am gearing up for this one and this is why I ask the question.
I want the ESC and motor ready for when I do so thanks for your help and contribution of knowledge to my project.
sirdirk007 is offline Find More Posts by sirdirk007
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 11, 2005, 11:23 AM
PGR
Low AltiDude
PGR's Avatar
United States, CA, Costa Mesa
Joined Jun 2004
7,869 Posts
455 Buick Wildcat?

Pete
PGR is offline Find More Posts by PGR
Reply With Quote
Old Mar 11, 2005, 01:38 PM
crashin with a smile
sirdirk007's Avatar
Los Angeles Industry, California, United States
Joined Jul 2004
1,149 Posts
ha ha ha
sirdirk007 is offline Find More Posts by sirdirk007
Reply With Quote
Old Mar 11, 2005, 01:46 PM
Registered User
vintage1's Avatar
East Anglia, UK
Joined Sep 2002
29,693 Posts
AXI 2820/10 or maybe the new MPjet outrunner.

I think you will need a 10x10 or 9x9 for best top speed tho.
vintage1 is offline Find More Posts by vintage1
Reply With Quote
Old Mar 11, 2005, 01:47 PM
Registered User
Ron H's Avatar
Bishopville S.C.
Joined May 2003
3,932 Posts
Even a triple won't give you the power needed. Maybe one of these?
http://www.balsapr.com/catalog/motor...ductId=U603500
Balsa Products - Motors And Parts - Feigao 540 Brushless Motors
Ron H is online now Find More Posts by Ron H
Reply With Quote
Old Mar 11, 2005, 02:59 PM
Registered User
Jimbo45cn's Avatar
Southwest Florida
Joined Mar 2004
3,246 Posts
55 inch wingspan with 6 or 7 servos and retracts, and it only weighs 2lbs? Is that the dry weight before all the gear goes in it, or is that auw? if not, I sure want to see a picture of this thing. i have lightnened my 40 gas conversion almost as much as humanly possible, and I can't get it under 4 lbs.
Jimbo45cn is offline Find More Posts by Jimbo45cn
Reply With Quote
Old Mar 11, 2005, 04:22 PM
crashin with a smile
sirdirk007's Avatar
Los Angeles Industry, California, United States
Joined Jul 2004
1,149 Posts
Right Jimbo Total weight is less 2lbs dry. I estimate total with all ready to fly would be around 3 at most. Of course this depends on what battery pack I go with but the idea is about right.
sirdirk007 is offline Find More Posts by sirdirk007
Reply With Quote
Old Mar 11, 2005, 04:24 PM
crashin with a smile
sirdirk007's Avatar
Los Angeles Industry, California, United States
Joined Jul 2004
1,149 Posts
I neglected to state the 40 I had in it is oversized. It called for a .25 when I got it but I am a stickler about power.

Vintage1 I have a double stator now that turns a 1080 no problem at all but could you tell me what the diff is between a 10" prop on that versus a 10" prop on a 540 motor or so.
sirdirk007 is offline Find More Posts by sirdirk007
Reply With Quote
Old Mar 11, 2005, 04:43 PM
Plane dodger
KillerAir's Avatar
Stratford Sikorsky, Connecticut, United States
Joined Dec 2001
6,715 Posts
You'll need over 300 watts of juice or a motor cabale of 30+ amps. Do you plan on winding your own or buying one?
Might get away with a Mega 22/20-3 or 4, the 2 Vintage mentioned or maybe one of the Multiplex 480's.
As for 10 inch props a 100 watt motor like the axi2212-34 pulling 8-10A will turn a 12" prop at ~5k rpms but the pitch speed is not pylon fast maybe closer to 25mph in contrast to a 540 size brushless pulling 30-35A turning closer to 11k rpms with higher pitch.
KillerAir is offline Find More Posts by KillerAir
Reply With Quote
Old Mar 11, 2005, 06:04 PM
Registered User
vintage1's Avatar
East Anglia, UK
Joined Sep 2002
29,693 Posts
Quote:
Originally Posted by sirdirk007
I neglected to state the 40 I had in it is oversized. It called for a .25 when I got it but I am a stickler about power.

Vintage1 I have a double stator now that turns a 1080 no problem at all but could you tell me what the diff is between a 10" prop on that versus a 10" prop on a 540 motor or so.

RPM?



Seriously, I habve no idea what you motor turns a ten inch prop at. I do know an AXI makes a good fist of a 11x7 on 3s LIPO, and a 10x10 should be simiular power wise, but with more pitch speed.

However you mighty want to go a little madder and uses a direct druve inrunner and try and get an 8x8 prop up in the upper teens RPM wise. That, if youahave teh power, can be fearsome.

In the sort of 300-400 watts arena - say 30-40A on 3s LIPO something lke a mega 22/30/3 on 3s LIPO and an 8x8 will do 12K rpm and deliver 30 oz of thrust and a 100mph pitch speed? 30A draw give or take.

If its out and out top speed required that's a better bet than an outrunner.

To get 40 sort of performance you are going to have to look at something more like 600W. BIG pack.

It can be done with a direct drive hacker and a fistul of lithiums...
vintage1 is offline Find More Posts by vintage1
Reply With Quote
Old Mar 11, 2005, 07:25 PM
crashin with a smile
sirdirk007's Avatar
Los Angeles Industry, California, United States
Joined Jul 2004
1,149 Posts
Wow thats a huge pack and amp pull. Maybe I could just stick to gas with this one. I have been up in the teens with my double stator and 1080 prop but what I was wondering is will the slow fly or direct electric prop pull in the same manner as a gas 9-8 or 10-8. This always ponders me because in slimer style the bigger the motor the more power and larger prop. I assume electric is somewhat the same however after winding a couple of my own brushless and useing some I have bought I see that different winds can also turn larger props with more or less amp pull sometimes. I guess the object will be trial and error. I also wonder if a gearbox would be better to turn the larger prop yet reduce amps and therefore allow more life from the pack as well as save in weight on a somewhat smaller pack.
Thanks vintage and I love to read your feedback response. It is nice to find someone who loves to help.
sirdirk007 is offline Find More Posts by sirdirk007
Reply With Quote
Old Mar 11, 2005, 10:49 PM
Registered User
Airdrie, AB Canada
Joined Sep 2004
1,049 Posts
Heh. 40 slimer to double stator cd. Me thinks you will prefer the slime.

The challenge is the words pylon racer. How fast is fast enough? 100 mph? A very small slick plane like a microjet takes around 250w on a 5x5 prop to hit 100. The amped up speed 400 racers are well over a hundred at 300w.

But this is bigger and draggier. Lets say you could get by with a 7x7 and have enough thrust to be happy. A Mega 16/25/3 (kv1700) will take you there at around 30A on 3s 15K (300w) on the prop direct drive. It is a reasonably small motor at 3oz. Can be pushed to 400w easy.

That 22/30/4 takes almost 900w on 6s to tag 95 mph on a 10x8. At the 12.5K required you are making 125oz of thrust static. You just don't need it on a pylon racer.

If you figure out how fast you want to go. Roughly how much prop diameter you need for thrust. (Probably less than 7 inch for a racer) You should be able to hit your power system easy. I'll bet money you end up somewhere around 150w per pound to get pylon performance. Might get away with less if slower is ok.

Mike
mjws is offline Find More Posts by mjws
Reply With Quote
Old Mar 13, 2005, 03:14 PM
crashin with a smile
sirdirk007's Avatar
Los Angeles Industry, California, United States
Joined Jul 2004
1,149 Posts
mj I was thinking around 100w per pound or so. I have no need for extreme speed considering where I am flying it. I just would like to get it up in the air and play a little. I wonder if a triple stator with 14 winds of 22g or so. I will do a motor calc to see. Again if I can get her in the air and do around 50-65 thats fast enough for the field I fly in.
sirdirk007 is offline Find More Posts by sirdirk007
Reply With Quote
Old Mar 13, 2005, 05:44 PM
Registered User
Jimbo45cn's Avatar
Southwest Florida
Joined Mar 2004
3,246 Posts
OK,
At 3lbs auw I have something for you, and it's not expensive. I am using this system in my 4lb tiger bipe conversion, and it flys the plane very well. No it will not hover, but that;'s not what I am looking for either. Endoplasma 16 turn brushed ( I know I just said a dirty word) motor, Great planes gd 600 gearbox, WITH THE 3.3 TO 1 GEAR,
Jimbo45cn is offline Find More Posts by Jimbo45cn
Reply With Quote
Old Mar 13, 2005, 05:48 PM
Registered User
vintage1's Avatar
East Anglia, UK
Joined Sep 2002
29,693 Posts
Excellent choice. Also mag mayhem on 10 cells/3s LIPO and Astro 05 cobalt. But you don't want to gear thses for speed - something like a 5-7" prop is best for speed.
vintage1 is offline Find More Posts by vintage1
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion OT: Another one... let's see if you guys get THIS one Akura2 Motorcycles 16 Feb 25, 2006 09:56 AM
See if you can guess what this was... David Hogue Electric Plane Talk 66 Sep 09, 2004 02:41 AM
Bet you guys can do better than this... crashsiegel Micro Helis 2 Aug 19, 2004 03:27 PM
See if You Can Find The Face in This Pic DNA Humor 64 Aug 06, 2003 05:42 PM