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Australia, VIC, Melbourne
Joined Nov 2006
6,277 Posts
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In the Vampire thread....
(My only video for now... but hopefully decent videos of all aircraft coming over the next weeks). You might have to follow 'blurred blob' for a lot of it! LOL. But there are enough clearish periods to see speed. Of course, just any small zoom change means an even 'faster' plane.... so there is no true reference. Only radar, GPS or RCspeedo etc can tell a usefully accurate speed. Oh, after take-off it is about 70% to 80% throttle all flight. Though 100% is not any huge leap ahead in speed. ...
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http://www.bocabearings.com/
Buying another cheap motor may give you the same problem(bad bearings), how many do you buy before you get a good one. Replace bearings and it should be good to go for quite a while. |
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santa barbara, CA
Joined May 2009
2,908 Posts
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Australia, VIC, Melbourne
Joined Nov 2006
6,277 Posts
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The Lander 6S 5 blade versus CS10 HET 2W30 numbers:
Sort of sustained, after 20secs approx. (not peaks) CS10 HET2W30-2200kv 6S 4000Mah 30C 63.7A 19.8V 1260W 1.9Kg DPS 70mm 2550KV 6S 4000mAH 30C 51.4A 21.8V 1120W 1.95Kg Exact same battery (recharged for each test). You can see that the Lander did the same thrust (a bit MORE really) for 140W less power. 12 Amps less. The voltage drop on the CS10/HET probably shows how much more load it was under, whilst the Lander had a pretty easy job with its load. Even allowing for a bit of error here or there, the difference is so large it will always still be a very clear win for the Lander. And applies to all low blade count fans versus CS10/12. The Lander motor is obviously capable. The HET 2W30 is also a capable CS10 6S motor. But it is the LOAD difference... FAN... that is the cause of the major part of the result difference I should have used two Landers in the plane these were tested for (rather than 2 CS10 HET's) as the CS10's, in this aircraft's case, don't even help the sound (jet-like) much at all. So the power 'cost' is not even giving anything else back in any form of sound benefit really! The ducting system just doesn't help that almost at all. ... Oh.. and the Lander CS10-70.... CS10 Lander 2960-2200kv 6S 4000mAH 30C 64.0A 19.9V 1274W 1.82Kg Again the same battery, but obviously a bit of motor difference (KV error and/or design) to the HET CS10...... but very much the same area of result. So those two back each other up, seeing they do give those close numbers with CS10's. |
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Greece, Attica, Athens
Joined May 2011
2,004 Posts
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Quote:
The battery in theory can deliver 4x30Amps but clearly in practice it can only deliver around 50amps and hold voltage at 22v. The 2V difference is very significant and I don't know if 2200kv is the best kv to compare with the lander's 2550kv. Although the results speak and the conclusion is valid, I don't think we can generalise that it will hold true with other motor choices. I cannot see how the Lander 5blade wins hands down since it most probably would not benefit much by a better battery. I have the same Lander and I get the same thrust results(1.95-2Kg) irrespective of battery. The specific CS10/HET combo on the other hand would provide much more thrust with a better battery. My Lander 10Blade 6S pulls 2.4Kg with a battery that holds 21.5V. |
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Australia, VIC, Melbourne
Joined Nov 2006
6,277 Posts
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You have only pointed out more info on what shows the CS is less efficient.
"The specific CS10/HET combo on the other hand would provide much more thrust with a better battery." That means you are saying that would hold a higher voltage.... Which then must use a total of more power, because more Volts will cause more Amps, meaning a total or more Watts. It is already using more power... by 140W... to achieve less thrust than the 5 blade. The issue isn't what a CS10 COULD do... but what it DOES do for X Power. And that is LESS OUTPUT than a low blade count fan. It is actualy a nice fluke that these three setups I used do have close to the same thrust outputs... thus making it very easy to see and highlight how the CS10 is a measurable amount worse than a low blade count fan. The 2550kv to 2200kv difference is an expected requirement of a low blade count versus a 10 blade. The lower blade area will be need more RPM to move the same air - which is what it shows. (Not that the exact same amount has to be moved... just the same total thrust, however it does that). It seems you are thinking of how to prove the CS10 CAN produce more thrust... but that is not the issue. The issue is what it COSTS to make the SAME thrust with a CS10 instead of a low blade count fan. You are PAYING for its only real benefit of being a QUIETER fan, which then allows the "whoosh" (White Noise) to be heard above "leaf blower noise". There is no other benefit of using a higher blade count at all.... just to be a quiter fan. "Faster and more Micro Cuts" of air are much quieter than "Slowerand less Large Chunks" of air. |
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More conjecture here as I have no numbers other than power at the moment.
Last night I removed the CS10 fan and replaced it with the 6904 (four blade). Both ran on the same motor (HET 2W-25 2660kv) with the same battery (5S 3000 MaH 40C). The Wattmeter was reading roughly 1100w for both fans, slightly higher amp draw on the CS10. What was evident though was that the 6904 has noticably more punch. I would consider myself a pureist and have a totally open mind regarding which fan might be better, but I really don't need a thrust tester to be able to tell the difference here. The 6904 on this setup wins hands down. One thing that does perhaps bias the above results is that this setup may not be optimal for the CS10 as this motor is undoubtedly a better match for the 6904. I flew the F-4 on the Changesun last weekend, will do so on the 6904 this weekend and hopefully have some video to post. Caveat emptor: Thrust test was not made on a dedicated thrust meter but by simply by hanging the model by it's nose. 'Tis what know as testing o'natural! |
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Greece, Attica, Athens
Joined May 2011
2,004 Posts
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Quote:
Some people in here have provided test results that show the CS10 to be comparable to other fans in terms of efficiency. Your experience is different. I have been able to get these results in my 4S and 5S models. In reality I would like to have more motor options for the 10 and 12 blade fans to find the kv/length of can for each application. The motor choices are a but limited now. |
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Australia, WA, Perth
Joined May 2007
3,088 Posts
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I think comparing a well-designed, low blade count fan to a "I'm assuming it's been designed?" high blade count fan is a bit of apples/oranges.
Stu's fans outperform a Wemo, yet have more blades? Likewise, choice of motor will have a huge effect. A Haoye being spun by a Neu will probably do fairly well! |
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Australia, VIC, Melbourne
Joined Nov 2006
6,277 Posts
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This is the CS10 Lander using a Nano-Tech 65C battery.
I do a number of battery tests across fans, but try to keep comparisons grouped. But also mainly with combo's (motor/fan/battery) that I have decided to use in an actual aircraft I am setting up. CS10 Lander 2960-2200kv 6S 5000mAH 65C 74.7A 22.32V 1668W 2.14Kg (It does 1820W peak (79A), for 2.25Kg thrust) Quite a few of my EDF tests are on my YouTube page: -- http://www.youtube.com/playlist?list...ature=view_all -- If you were to use that combo in a plane you would be very prone to ending up with motor failure, because you are likely to "over-do" WOT usage and even at the lower sustained numbers the motor gets very hot. Use WOT coming off "rests" and it will be more towards the 1800W area for those runs. Also any plane with that power would be excessive anyway.... just a fun "Wow! Look at my fast plane!" sort of thing. Fine to do if you want, but thus in those higher failure areas. 30C to 40C is plenty for this combo and "auto limits" the max powers, whilst the battery is still not over-specced and will cope fine. The 4000mAH 30C doesn't even get very warm, which shows it is totally fine doing its lower power job. |
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