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I agree with Manta, should give you nice power and speed. But like Manta, I would be concerned about heat.
Here are some ideas to help improve cooling: https://www.rcgroups.com/forums/show...postcount=7731 Robert Quote:
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Crap im trying to figure out how im going to explain this.
On the watt meter,,, I never really paid any attention to the Wp reading on the bottom left hand side, I always just read what was measured on the bottom right hand side where the W (watt) instant read out is. Now is the Wp reading ever different from what I have been going off of? It's just the max watt's that was measured right? uhhhhhhhhhhh |
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Jordan,
Here is the test results we did at Fly Low. Vyper 65" Turnigy SK 5065-380 Turnigy 19x10 6S Battery, Size 4000 mah, C Rating 30 Turnigy 85amp ESC AUW - 8 lbs 6 oz WOT Sustained Thrust - 13 lbs 15 oz Total Volts at WOT - 22.9 AMPs at WOT - 65 Total Watts - 1488 Total Watts Per Pound - 178 Thrust to Weight Ratio - 1.7 to 1 |
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That's some good numbers then. I'm going with the same setup and a 20x10. Should be perfect for me.
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Haven't got that far along in the thought pattern yet. I know I need to collect a lot more data points to make it valuable.
I need to retest your planes and others that I have tested and fill out complete forms that I have come up with for each plane. As I get more data I will place in a spread sheet for sharing. Robert |
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Last edited by Robert Youens; Jun 16, 2010 at 08:10 PM.
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Motrolfly 4325-380 Testing
Here is the testing results on Lonelasso's 70" Slick with Motrolfly 4325-380. We used a range of props. The battery was not new, and did not hold voltage under load as well as expected. This could explain why the total watts produced were a bit lower with the 19x10 prop than Manta1's 2200 to 2300 watts. Could be a difference in prop brand and model also. Still the test was valid and the results indicate that this is a great motor to run on 6S and get some kick ass thrust to weight ratios.
The 18x10 drew a little more amps than expected, could be the prop brand and model, but it seems consistently true, that on the planes I have tested that 18" props are just not as efficient at creating thrust on this plane as 19 and 20 inch props. Note: Just because lonelasso's 380KV motor on 6s can turn a lower pitched 20" prop, it does not mean that this would be any where near the optimal prop for other systems. On some higher KV, higher RPM set-ups it may not be possible to turn a 20 inch prop without excess heat or amps. To me the obvious choice in prop for this set-up is the 20x8 which drew 84 amps and produced a 1.6 to 1 thrust to weight ration. With a newer battery this should be noticeably better. The 20x10 produced a whopping 1.75 thrust to weight ratio, but a cost of 92 amp draw. This is going to go up with a fresh pack. In my opinion, I like to leave a little more head room on battery capacity. We were using a 20C 5000mah pack which should deliver 100amps, and voltage is going to fall off quickly pushing pack limits so closely, not to mention heat issues. I wouldn't recommend a 20x10 prop, heating is likely going to be an issue. With it's large motor diameter and shorter rotor length, this motor should run cooler. But the smaller diameter, longer rotor motors seem to deliver similar thrust with a bit lower amp draw, at the cost of less air flow through the core and more heat issues. All in all, in my opinion a very fine choice for the 70" Slick. Take a look a the spec sheet and judge for yourself. I plan to purchase a radar gun in the future and we can put some speed numbers to the testing to round out the results. I hope you enjoy the data. Robert |
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Last edited by Robert Youens; Jun 18, 2010 at 12:59 AM.
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hmmm uhhh,I dont think its a grea idea to run 20 or over props on this motor.Not in hot climate anyhow.What batteries are you running in it?I tested with thunderpower pro lites.v2 Maybe Ken will see this and sound in.I tested a 20x10 on it.WAY more power than one would need.Motor temps went up there a bit too.Maybe i need to get a different wattmeter
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Lots of good info there.....And while an 18 inch prop may not be the most efficient for this size airframe, mine has no problem effortlessly pulling out of a hover on an 18x8 Xoar.
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We were running a Turnigy 6s 20C 5000mah that was not new, not sure how many flights. A higher C rated battery would surely keep voltage up and produce more watts. If you would try a 20x8 I believe you would see an amp drop of about 8 to 10 amps and still maintain really nice vertical and reasonable speed. At least that is what our test indicated.
If you will review the results in the attachment below, we tested with a selection of props. Dave has run the plane a few flights with the 20x10 and did not get overheating, admittedly they were not long flight and the plane was not being pushed hard. As I recall it was in low 90's when we were doing the temp tests. By dropping to a 20x8, the tests indicate that it will probably be OK run more agressively. I am sure Dave will let us know. On my Turnigy 5065-350kv, I am pulling the 20x8 with no heating issue. I have run it in 100 degree F heat and never seen motor temps over 130F and esc temp over about 120 F. Battery is no more than 110 F. Drawing around 75 amps. With temps in low 90 F, battery and ESC ambient and motor less than 120F. I am running a 30C battery and holding right at 4 volts per cell in static full throttle test. Quote:
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Hey guys, wondering if anyone has seen this before. Tonight my motor instantly ground to a halt. Luckily I had just pulled out of a harrier and had lots of altitude for a nice deadstick landing. 5 seconds earlier and I would have lots of repairs!
After inspection I found that my Hacker A50-14L had the large inner bearing move forward and make contact with the windings. This caused the windings to melt and actually spray out of the cooling holes and around the cowling. Not sure if I should get another Hacker for the Slick or not? I was running an Xoar 18x8 on 8s, for approx 2000 watts. My motor was coming down around 130 deg, and I just installed cooling baffles to make it run even cooler. This was only the 8th flight on it. I had the circlip and the wheel collar installed on the shaft behind the motor, so nothing should have been able to contribute to the bearing moving. What do you guys think? Is it worth notifying Hacker? Was it a freak accident? Hope it didn't fry my X80 too.... |
Last edited by G.P.; Sep 01, 2012 at 09:05 PM.
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Every set up is individual and specific to the total system as well as the flying style of the pilot. This info is just the facts of tests on a specific motor, esc, prop on a 70" Slick.
Robert |
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Last edited by Robert Youens; Jun 18, 2010 at 12:34 AM.
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Quote:
SteveT |
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Latest blog entry: My old shop....
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