HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by fly_boy99, who may elect to delete unwanted replies.
Old Jan 08, 2008, 03:02 PM
Flying motor mount master
fly_boy99's Avatar
San Jose, California, United States
Joined Oct 2004
8,745 Posts
Discussion
Impressed for $28 bucks!!!

EDIT: I added a new graph after changing the timing on my ESC to high. It seems to run better now and has a bit more pep!!!

Well folks I think I may have found a really nice economical EDF setup that folks can use on airframes that weigh less than 1.5 lbs.

The setup:

HXT 2835 (380S) 3900kv Brushless Inrunner
http://www.hobbycity.com/hobbycity/s...idProduct=4200

EDF Ducted Fan Unit 5Blade 2.68inch 68mm
http://www.hobbycity.com/hobbycity/s...idProduct=4500

The performance is in my Eagletree graphs below. First run was on 3S with a 3S TP Extreme 2200mah V2 pack and the second run was with a 4S Evo 20 2500mah pack.

Time to get an anemometer to figure out efflux speeds....

Check it out you won't be dissapointed,
B
fly_boy99 is offline Find More Posts by fly_boy99
Last edited by fly_boy99; Sep 16, 2008 at 07:13 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 12, 2008, 09:58 PM
there is no spoon...
Cap232ac's Avatar
Pueblo, Colorado
Joined Jul 2005
592 Posts
Oops, thought this was an A-4 thread.
Cap232ac is online now Find More Posts by Cap232ac
Last edited by Cap232ac; Jan 14, 2008 at 11:11 PM.
Reply With Quote
Old Jan 14, 2008, 12:06 PM
Registered User
Joined Sep 2006
1,534 Posts
Quote:
Originally Posted by fly_boy99
Well folks I think I may have found a really nice economical EDF setup that folks can use on airframes that weigh less than 1.5 lbs.

The setup:

HXT 2835 (380S) 3900kv Brushless Inrunner
http://www.hobbycity.com/hobbycity/s...idProduct=4200

EDF Ducted Fan Unit 5Blade 2.68inch 68mm
http://www.hobbycity.com/hobbycity/s...idProduct=4500

The performance is in my Eagletree graphs below. First run was on 3S with a 3S TP Extreme 2200mah V2 pack and the second run was with a 4S Evo 20 2500mah pack.

Time to get an anemometer to figure out efflux speeds....

Check it out you won't be dissapointed,
B
Did you balance the fan? I wonder how well the motor will hold up under 4S. their spec only go up to 12V, but at 40A. That's 480 watts. 4S at 28A is only 415watts, so it's within the limit. I'm more worried about heat.
rcboosted is offline Find More Posts by rcboosted
Reply With Quote
Old Jan 18, 2008, 04:34 PM
Flying motor mount master
fly_boy99's Avatar
San Jose, California, United States
Joined Oct 2004
8,745 Posts
The fan was balanced perfectly, I worked on the rotor awhile ago and no problems there.

Yeah they say it is only good for 25A but I think that's so they don't get any returns. Even when I ran it up to 500W and checked the temp windings they were only 100degrees. I couldn't believe my eyes!!!

I don't plan on running it WOT all the time but in bursts and I'll be logging the flights with the Eagletree elogger. So time will tell.

B


Quote:
Originally Posted by rcboosted
Did you balance the fan? I wonder how well the motor will hold up under 4S. their spec only go up to 12V, but at 40A. That's 480 watts. 4S at 28A is only 415watts, so it's within the limit. I'm more worried about heat.
fly_boy99 is offline Find More Posts by fly_boy99
Reply With Quote
Old Oct 02, 2008, 12:18 PM
I make bad look so good.
SteveC68's Avatar
League City, Texas
Joined Sep 2006
2,502 Posts
I've been looking at this motor and fan for a while now and I've come to the conclusion that this motor is not 3900kv as advertised. It has to be lower. The Hobby City 68mm fan is a knock off of the Wemo mini fan. Based on that both fans should provide similar performance and thus similar load on the motor. On 4S you got 43k rpm. Now Carl Rich on a Medusa Research 28-40-3400 got 44.4k rpm on a mini fan on 4S. That means his 3400kv motor was spinning more rpm than the Hobby City 3900kv motor both on 4S, and both running basically the same fan. The kicker is Carl was seeing 55amps and 817watts. I'm thinking the Hobby City motor is more likely a 3200kv or so. Still it's a great deal at $19. I wonder if it would survive 5S.

Steve
SteveC68 is offline Find More Posts by SteveC68
Reply With Quote
Old Apr 09, 2009, 09:54 AM
Registered User
Dr Kiwi's Avatar
Chattanooga, Tennessee, United States
Joined May 2003
27,195 Posts
Two choices here: either the 3900 HXT is, as you say, perhaps closer to 3200Kv..... or, it is inefficient and over-loaded which would also explain its lower rpm than the more efficient Medusa.
Dr Kiwi is offline Find More Posts by Dr Kiwi
Reply With Quote
Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion T-bird 18 for 28 bucks. Forester Hot Online Deals 11 Mar 14, 2007 10:38 PM
I can squeeze your sleeves for 15 bucks a piece. Squeeze Nitro and Glow Power Cars 3 Nov 20, 2003 11:15 AM
I can squeeze your sleeves for 15 bucks a piece. Squeeze Engines 1 Dec 03, 2002 04:00 PM
Poppy for 60 bucks mmm208 Aircraft - Electric - Airplanes (FS/W) 2 Nov 19, 2001 10:21 AM
Zagi Battery Packs for $28 ?? costath Foamies (Kits) 2 Sep 11, 2001 03:46 PM