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Old Jul 12, 2005, 05:38 PM
nuttcase21 is offline
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New Project: 24" snappy on 3 cells with a razor m*killer!!


i put a razor 400 on my first snappy and now i'm smitten with it. so ofcourse i had to make a faster one. i'm planning on using another 24" snappy wing heavily reinforced with carbon. power will come from a TP prolite 2000mah 3 cell pack, a pheonix 25 controller and one of razors new m*killer 1/18 scale truck motors. kv for this little bugger is 6800 rpm. at three cells that's 85,680 rpm unloaded!!! thinking of using a gws 4x2.5 prop if it'll hold together. think it will or is 3 cells a bit much? now that i think about it, razor stators are only rated to 50,000 rpm huh? oh well, we'll test it's durability. tell me what you guys think.
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Old Jul 12, 2005, 07:28 PM
raptor22 is offline
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What i think is that you are almost definitely going to fry that little motor.

--Alex
Old Jul 12, 2005, 07:36 PM
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"I passed on the kool-aid"
That sounds like a recipe for disaster....An expensive one at that. That motor is probably too hot for two cells.
Old Jul 12, 2005, 09:12 PM
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I am using that motor on my custom 28 inch R/Cworks wing, I call it the howler monkey :-)


with a poly quest 1500 2s 20c pack 4x2 apc Castle 25 it pulls around 19 amps static full.

I can't tell you exactly how fast it is but it is crazy.
Old Jul 12, 2005, 09:16 PM
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The quote from mfg's website is nice:
"RZ-MK (M* killer for cars) and HOT aircraft applications"
http://www.razormotors.com/htm/catalog/motors.htm
Old Jul 12, 2005, 09:18 PM
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Quote:
Originally Posted by skylinux
remove

RZ-MK
Old Jul 12, 2005, 09:47 PM
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"I passed on the kool-aid"
I think when they said "HOT aircraft applications" they meant using it geared or on 2 lipo cells or less. If you give it a try you might want to get some eye protections because I do not think that GWS prop will last long not to mention that it will probably flatten out some as the rpm's get really high.
Old Jul 12, 2005, 09:54 PM
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Quote:
Originally Posted by zmonte
I am using that motor on my custom 28 inch R/Cworks wing, I call it the howler monkey :-)


with a poly quest 1500 2s 20c pack 4x2 apc Castle 25 it pulls around 19 amps static full.

I can't tell you exactly how fast it is but it is crazy.
I sure it make a racket but dought if it is really all that fast. It is perhaps turning 35,000 which would be a prop pitch speed of 66.5 MPH. A decent CDR single on 3cells with a 4X4 can turm 26,000 for a prop pitch speed of 98.8.MPH.


Charles
Old Jul 13, 2005, 12:11 AM
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If you are SURE you need to try this, at least go with a 3 inch or smaller prop.
Old Jul 13, 2005, 12:42 AM
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to be honest, if it blows up i'm really only out the motor, and they're on sale right now for like 75 bucks if i remember correctly. it'll be a BLAST i'm sure when i try it. one question i have is where can i get props smaller than 3" from?
Old Jul 13, 2005, 01:03 AM
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The 'go fast' motor for the 24" EPP delta Concrusher is a Himax 2025-5400 with a GWS 3 x 3 drilled out and CA'd to the shaft, and 3S1P TP-2100/s. There are several people who claim radar measured speeds in excess of 100 mph with this set up. See https://www.rcgroups.com/forums/show...&postcount=433

MotoGuess says +50K RPM....maybe and maybe not, but is sure sounds fast. Mine goes fast enough with a Razor 300... maybe 75-80 mph which is still very fast for that small a plane. Woooosh and it is too small to see

Your limiting factor may not be over reving the motor, it may be trying to keep the prop on the shaft.
Old Jul 13, 2005, 05:17 AM
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Quote:
Originally Posted by everydayflyer
I sure it make a racket but dought if it is really all that fast. It is perhaps turning 35,000 which would be a prop pitch speed of 66.5 MPH. A decent CDR single on 3cells with a 4X4 can turm 26,000 for a prop pitch speed of 98.8.MPH.


Charles
actually it's a 4.2 x 2 APC at 45,880 rpm with a total fly weight of 9.5 ounces ,and yes it is very fast would you like to run it :-) the GWS props hold up for the lesser razor motors that I run on mine other wings but start to collapse at these higher RPMs.
Old Jul 13, 2005, 06:29 AM
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Quote:
Originally Posted by zmonte
actually it's a 4.2 x 2 APC at 45,880 rpm with a total fly weight of 9.5 ounces ,and yes it is very fast would you like to run it :-) the GWS props hold up for the lesser razor motors that I run on mine other wings but start to collapse at these higher RPMs.


Round RPMs to 46K , 46*2*.95=87.4 MPH prop pitch speed so still looks slower that a decent single CDR. My MiniSpeed Wing 250 is 10.3 AUW with CDR,3S TP ProlItes 1320 and tachs 26K with a 4X4 after a five minute flight with battery resting voltage at 11.3. There are a bunch of over 100 MPH small wings around these days.

Mini Speed Wing 250.

Being smaller the 250 seems almost as fast as this SpeedWing 400.


Charles
Last edited by everydayflyer; Jul 13, 2005 at 06:42 AM.
Old Jul 13, 2005, 06:44 AM
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Quote:
Originally Posted by everydayflyer
Round RPMs to 46K , 46*2*.95=87.4 MPH prop pitch speed so still looks slower that a decent single CDR. My MiniSpeed Wing 250 is 10.3 AUW with CDR,3S TP ProlItes 1320 and tacks 26K with a 4X4 after a five minute flight with battery resting voltage at 11.3. There are a bunch of over 100 MPH small wings around these days.


Charles
Using a speed calculation chart for GWS props can be very deceiving, when I have tried the thin GWS props on this motor speed was greatly reduced, I would like to try a bit more pitch but I haven't found a fiber prop with a say 3 pitch the next step I found is a 4 pitch might be a bit too much. I don't know what the wattage and amp Max is for this motor.
Last edited by zmonte; Jul 13, 2005 at 07:01 AM.
Old Jul 13, 2005, 01:01 PM
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i saw a graupner cam 4x3 at my lhs


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