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Old Mar 16, 2013, 11:27 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Originally Posted by brathanke View Post
Sad day for me... my slick ate it on a deadstick. I think I have an electrical gremlin of some sort. The motor was running awesome and then cut out abruptly like I hit the kill switch... but I didn't...

Anyway it was about 40 ft high with the nose pointed up and no speed. It dropped like a rock. I managed to get the nose up a little but it hit had and broke sideways right behind the canopy. Broken prop and who knows what else up front... I have not taken the cowl off yet. I hope the new motor is ok.
Sorry to hear this Nate.....

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Old Mar 16, 2013, 11:39 PM
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GoldCraft's Avatar
United States, GA, Woodstock
Joined Jan 2007
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Originally Posted by ryan_m View Post
Quick question for the guys with a dle-30 on theirs...
what's your favorite prop? I've got a dle-30 slick that I bought from someone on the forums here, I've had two electric ones, and now I have a gas and electric one. I figure I'll ultimately only keep one of the two, but haven't decided which yet. I've got a Vess 19A on there now, that is what the plane had. Seems ok, just wonder if there are any better choices out there for the plane.
I like the 20x6 Xoar the best.......good power, nice pull out out of hovers, slows the plane down nicely on downlines and landings.
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Old Mar 17, 2013, 12:19 AM
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Dennis C's Avatar
Grass Valley California
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Originally Posted by bryansifsof44 View Post
Thanks a lot... The couple of sources I use have always got me right on the money. However the RPMs I figured have nothing to do with any calcs, they are hard numbers. The voltage may be a slightly lower, which is possible if you are seeing more sag with older batts. I assume Hacker is close with their kV.
got the numbers for the Hacker A60 5s

30 volts
78 amps
2340 WATTs
6900 RPM
APC 20x11e
8s 4000 Glacier 30c

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Old Mar 17, 2013, 12:47 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
27,994 Posts
You got pretty much identical to what I get with my set-up... This is from my original run-up...

Quote:
Finally!!!! My Edge is ready for maiden tomorrow!! Had to buy new batteries as the ones I had (4000mAH packs) had puffed, and, I also needed more weight in the nose, so, went with new 4S 45C 4400mAH Thunder Power packs. And.... I ran up the motor today for the first time. On 8S with a Hacker A60-5S (295KV), I got 2335 watts @ 79.35 amps, using a Xoar 20X10 Carbon fiber wide "gas" prop. While I didn't check the thrust with a fish scale or anything, but I can tell you, when I had the stab pulling against the back of my ankles, it hurt, and I haven't even set my ESC yet!!!
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Old Mar 17, 2013, 12:59 AM
bryansifsof44's Avatar
United States, AK, Anchorage
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Quote:
Originally Posted by Dennis C View Post
got the numbers for the Hacker A60 5s

30 volts
78 amps
2340 WATTs
6900 RPM
APC 20x11e
8s 4000 Glacier 30c

Dennis
Again thanks for getting those numbers. I wonder if it is possible that the kV is lower then the spec says. With that motor, I would expect to see a efficiency between 80-86%... most likely closer to 86%. Which gives you a range of [6900(100/80) = 8625rpm / 30volts = 287.5kV @ 80%] to [6900 (100/86) = 8023rpm / 30volts = 267.5kV @ 86%]. Reports of the motor show it having a very good efficiency in the 85% range. Any thing lower then 80% I would assume would give you unwanted and excessive heat. Also, putting 270kV in the calculator gets real close to the numbers your are seeing.
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Old Mar 17, 2013, 01:07 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Well....I can tell you that mine comes down barely warm, I can easily get 6-7 minutes of flying time (and that's not low and slow stuff), and it hauls my 74" Edge and 72" Extra vertical as far as I want to go....and that's while swinging a Xoar 20X10 gas prop....(but I am thinking of trying a 21X10 Xoar)....

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Old Mar 17, 2013, 01:10 AM
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United States, AK, Anchorage
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Originally Posted by SteveT. View Post
You got pretty much identical to what I get with my set-up... This is from my original run-up...



SteveT.
What are your thoughts Steve? If one of you guys are down... you could check kV by running the Castle logger without a prop. Then you put the pointer just a a few seconds in on a power up (to get away from the initial surge).... take the RPMs (make sure you have the correct number of poles, in this case 28) divided by the voltage at that point which gives you your kV.
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Old Mar 17, 2013, 01:18 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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I was told that AeroModel (and other companies) use 8.6 volts to check the KV of a motor....So, I would assume, that you run the motor on 8.6 volts, and tach it? Or if you want to know the exact KV of a motor, you can send it to Mike at AeroModel and they will check it. Or if you are going to buy one,ask them to run it and check the KV for you....All motors will vary a little as to KV....ask Ken at Subsonic planes... Personally, I don't think the logging in Castle ESC's is that accurate....That said, I have not downloaded the data from the last time I flew either....I did have it turned on, so I might have to check it one of these days....

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Old Mar 17, 2013, 01:22 AM
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United States, AK, Anchorage
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How would you tach a motor without a prop? It's actually its pretty easy to do it with the logger... kV should be the same at any voltage or at least within a point or two.
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Old Mar 17, 2013, 01:26 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Quote:
Originally Posted by bryansifsof44 View Post
How would you tach a motor without a prop? It's actually its pretty easy to do it with the logger... kV should be the same at any voltage or at least within a point or two.
Many ways,(A contact tachometer for one) but tach it with a prop...I am just relaying what I was told... And personally, I'm just not that worried about it....I buy the motor recommended for how many cells I want to use, I install said motor.....put a battery (or batteries) in my plane, I hit the throttle, it flies, it has very good power, doesn't get hot, I get reasonable flight time....what else do I need to know.... (And it makes my brain hurt too much to worry about the other stuff)

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Old Mar 17, 2013, 01:30 AM
bryansifsof44's Avatar
United States, AK, Anchorage
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If you tach it with a prop, it will load the motor and you will see a lower RPM reading. kV is figured with out a prop on it (no load).
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Old Mar 17, 2013, 01:47 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Ok....but as I said....I'm just not that interested in it....it works, that's really all I care....

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Old Mar 17, 2013, 01:58 AM
bryansifsof44's Avatar
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Originally Posted by SteveT. View Post
Ok....but as I said....I'm just not that interested in it....it works, that's really all I care....

SteveT.
And thats fine... I am fascinated by how it all works that's is why I spend time at it. Anyways thanks for the input. BTW, before you edited your post you didn't include that you weren't interested... I wouldn't of pushed if you originally expressed that.
Bryan
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Old Mar 17, 2013, 02:09 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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No biggy....for me, I was just never into the math end of it....I'm more into the mechanical aspects of things....though yes, math is involved in that too.....

Give Mike Donovan at AeroModel a call.....he is "the man" about this stuff, and he can fill you in on all the "gory" details,including exactly how to check the KV of a motor...

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Old Mar 17, 2013, 02:33 AM
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United States, AK, Anchorage
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Quote:
including exactly how to check the KV of a motor
I got this part figured out... its just the RPM per volt at no load. Anyways I don't plan on buying a hacker any time soon (well maybe a Q-series, that is if Ken doesn't get his 50cc out before I need it), just trying to understand the 28pole motor and the low readings you guys are getting.
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