Posts: 293
Joined: 4/13/2005 From: las vegas,
NV, USA Status: offline
I just got a new Ulmer-rc Blink. Wing span 18”, currently the airframe weight with covering is 2.5 oz that’s with no hardware or anything installed yet. The popular power plant is .049 glow. I would like to try electric. What would be the best elec setup for all out speed? I have never ran elec before so I need motor size and battery.
_____________________________
You know you can’t spell when MS word don’t know what the ___ you’ve typed
Posts: 87
Joined: 7/12/2003 From: norman, OK, USA Status: offline
C rating is the amount of amps the batt. can give. lets say if you have a 1000mAh batt. at 10C rating this will give you 10 amps without getting damaged if you have 1000mAh at 25C you will get 25 amps. this all comes down what motor and prop you will use. lipos are 3.7V per cell so to go fast you will need like a 3cell (11.1V) and lets say mega 15-6-3 and 5x5 prop this will pull about 25-30 amps at 11.1 volts so you will be ok with 25C 1000mAh pack. also brushless motors have a KV rating that you need to know about. KV is 1000rpm per volt. so if you have 1000kv motor you will get 11000rpms with a 11.1V pack or 7300 rpms with 2 cell (7.4 V) pack. to go fast you need as much kv and volts you cen get away with, but there are many problems more volts and volts you get much more amps, then you have batt. and ecs problems......... hope this helps some
Posts: 10317
Joined: 11/22/2003 From: arlington,
WA, USA Status: offline
A 1.5 oz glow engine and 1 oz worth of fuel can get this plane going with a 4.2x4 prop at about 30,000 rpm, and it'll run on an oz for about 3 or 4 minutes flat out. This is the level of performance that I would like to see electric beat, in the same size package.
138 grams of gear= 4.86 oz.. heavier than the 2.5, but no throttle servo needed, and no fuel proofing needed. and high dollar nice stuff will be lighter , you could shave an oz or so off of that.
Posts: 10317
Joined: 11/22/2003 From: arlington,
WA, USA Status: offline
Thanks for those links. Last time I tried similar sized stuff it was disappointing to only get full throttle for half a minute then spend the rest of the flight at 75% power. IIRC, it was a 15C pack.
Posts: 227
Joined: 7/15/2004 From: Indianapolis,
IN, USA Status: offline
I still can't find the darn needle on these brushless jobs.. they'd be so much easier to run if I could lean em out instead of trying every prop under the sun to get what I like.
If you want to get full throttle and stay at full throttle get a polyquest pack, ~40c
at 4000 kv it should be good for ~ 30k on the same prop @ ~25A
I know , enough of the hobby city links, but with kids I have to fly the cheap stuff for now. I have to be happy with just drooling over over the nice stuff (neu motors are astounding!)
< Message edited by cncswiss1 -- 4/28/2008 1:58:36 PM >
Posts: 2795
Joined: 2/4/2002 From: Charlotte,
NC, USA Status: offline
You have to be carefull on what you get from hobby city. Many items, especially motors, are over spec'ed.
This looks to be the size of my mini-dust and I don't see an electric setup that would beat the .061 & .074 glow set ups I run on it. I'd be interesting if you do find a good set up because throttle would be nice.
_____________________________
Revver #125, Pico Owners Club #3 R/C Anonymous. My name is Evan and I have not flown for 14 hours.
Posts: 227
Joined: 7/15/2004 From: Indianapolis,
IN, USA Status: offline
yes some of it is over rated, or reviewed by folks that don't mind smoking one now and then. but with some testing and patience some real gem's can be found. sort of like shopping at biglots, you have to wade thru the junk to find the good stuff.