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Old Aug 30, 2014, 07:06 PM
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XPS 20,000 Watt Fan Attention XPS

"The interest in 20Kw systems declined."

"My current setup with the new airframe is 18S and about 15000 watts."

Jim, I started this thread becacuse I didn't want to clog up the Habu thread and saw your posts there, but have some questions about this.

I'm still here.

I don't understand how you get 20 kW out of this setup though. I was sifting through the XPS threads and the I cant even find one on the fan. Your website does not have the fan listed either so I'm not sure on the details. If your running at 18S and getting 15 kW how do you get this to 20? I remember a discussion about the RPM limitations on the speed controller being a limiting factor at 38,000 rpm. I thought the motor KV was 650.

It seems the threads on this fan have vanished, I would have posted there.

I have yet to plug this in but I do have some 24 cell 300 amp controllers that I would hope get me close. Can you connect the dots for me? Id like to push this to 20,000 watts or close to it.

Thanks

Rick
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Last edited by Air Head; Aug 30, 2014 at 10:10 PM.
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Old Aug 31, 2014, 10:34 AM
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Quote:
Originally Posted by Air Head View Post
. I was sifting through the XPS threads and the I cant even find one on the fan.
Did you find this thread?
http://www.rcgroups.com/forums/showthread.php?t=964477

Unfortunately there's of noise in it, as well as good information.
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Old Aug 31, 2014, 06:34 PM
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Thanks

I'm looking for information on running this with the higher cell counts. I think XPS sold this 20kW system but seemed to miss the issue of having a speed controller for it. Aside from Jim running on 15 cells I think the only other one was Joe - MCS guy, but he did not seem to get the advertised performance, and think he got rid of his. I remember he tried 16 cells.

Id like to hear about the 18 cell setup.
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Last edited by Air Head; Aug 31, 2014 at 08:23 PM.
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Old Sep 03, 2014, 11:15 AM
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There are several controllers available - in fact, you have one - the 24S controller. There were numerous 15S setups flown by our customers and a few 16S setups. As far as I know, I am the only person to run a 18S setup. The fan is simply too small for many applications that are requiring a lot of thrust. A 8" fan generates 40 pounds of thrust at just 18,800 RPMs and uses less than 1/2 the power that the 5" fan needs to generate 30 pounds of thrust.
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Old Sep 03, 2014, 05:36 PM
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"Id like to hear about the 18 cell setup."
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Old Sep 03, 2014, 09:05 PM
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It's 18S using a very modified 24S controller. It's design to run for about 20 seconds at full throttle before you shut if off and coast around. I built this strictly for the Guinness record setting event. I will probably fly this once and then retire it in favor of the larger airframe with bigger fan that can generate huge amounts of thrust with very little power (by comparison). I have learned a lot about size vs. performance. Look at the size of the turbofans on a 747. Look at the size of a fan in our jets. There is a reason why 747's don't have tiny little high RPM fans, and since we are not burning fuel to help provide thrust like warbird jets, we are in fact stuck using nothing more than an air pump. It's all about getting as much air as possible through the fan, as fast as possible. Volume produces thrust, efflux produces speed. Even a 6" fan is way better than a 5" fan, but the 8" fan is perfect because it fits pretty easily in most of the bigger turbine setups that would be using 160-200N turbines and gives you the same thrust.
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Old Sep 03, 2014, 09:21 PM
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Thanks Jim

I don't want to light a fire, I'm still waiting for the transmitter, but since you mentioned it is there an eta for this 8" fan? I think ill try 15 or 16 cells and see how that works out.
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Old Sep 10, 2014, 10:36 PM
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Have you looked at the Ailen Power thread. They have some very powerful esc. Biggest is 24s 450a, what's that, almost 40kw. Lots of smaller ones too.
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Old Sep 13, 2014, 01:37 PM
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Holy Smoke that's a big one!

And this is what worries me (SMOKE). Having a career in the industrial electrical field this sort of power in such a compact package really scares the hell out of me. 450 Amps would certainly provide some head room over what I thought my 300 amp controller would do.

I like the mention of the 8" fan Jim brought up. I haven't been able to focus much on the hobby for some time but I have a week off work coming up from some surgery and may get a chance to build my electrical buss to plug all the batteries together and finally run this thing. rvincent said he would help me with this when I get it all plugged in.

I also have a couple of Knife Liddles 4" Turbax setup I'm making, some full size Turbax, and a 120mm Change Sun 12 blade I'm messing with. I also picked up a couple Dynamax Fans I need to get some adapters for. These all have standoffs for outrunners and I'm trying to remember how to run a lathe to make these.

Hey Jim any idea when we can get hold of one of these 8" fans?
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Last edited by Air Head; Sep 13, 2014 at 05:19 PM.
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