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Old Aug 20, 2009, 01:28 PM
Registered User
Aylesbury,UK
Joined Apr 2000
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Delta-V 15 fan problem

Hi, I have fitted a Delta V 15 fan and the Eflite 3600kv motor to my KC F-18 kit. I have taken some measurements on the intended 4S 2250 30C Loong Max pack, which seem wrong. After the first peak of the freshly charged pack had gone, I was getting 850watts at 56 amps!! I am using a Pentium 60A controller on low timing. This is a lot more than I was expecting, and more than I have seen advertised on the site I bought it from.
I then tried it on a 3S pack, and got 400watts at 37 amps. This is also higher than I would expect, I thought it might be nearer 30 amps.
This was measured on an Astroflight watt meter. I am wondering what I can do about this, would I be able to use the transmitter end point adjustment to limit the speed controller from reaching full power? As much as 850watts might be fun, the motor wires were getting a bit warm, and the motor is supposed to be 750watts max. Help!!!!!
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Old Aug 20, 2009, 02:04 PM
turbonut's Avatar
upland CA
Joined Dec 2004
7,253 Posts
750 watts is the rated power not installed in a plane.When You add the ducting it loads the fan and raises the amp draw..I have measured as high as 900 watts installed in a the eflite Hawk.. your numbers look pretty much as what you should get..you should be fine!
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Old Aug 20, 2009, 02:47 PM
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Aylesbury,UK
Joined Apr 2000
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Ok thanks for that. The duct is quite open and free flowing compared to what I have seen of the Hawk, maybe thats why it is under the 900watts you got. Still seems a bit high, I was aiming for something around 600-650watts. I may take the fan out and try it like that out of curiosity.
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Old Aug 20, 2009, 04:21 PM
turbonut's Avatar
upland CA
Joined Dec 2004
7,253 Posts
I dont think you will see 650 unless you use a diffrent motor..the KV is going to make the numbers you are allready getting. I say run what you have..as long as there is good airflow in the fuse for cooling you should be fine
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Old Aug 21, 2009, 01:14 AM
Registered User
Aylesbury,UK
Joined Apr 2000
983 Posts
Thanks Turbonut. I have looked at a few threads regarding using the end point to restrict the throttle movement and reducing the overall output, some say ok and others no. I dont fly any of my EDF models at full power all of the time, so I would think it will work ok. I would like some more guidance from you guys out there please
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Old Aug 21, 2009, 06:56 AM
Julian T
Fleet, UK
Joined Jun 2005
520 Posts
Generally not considered a good idea. It depends to a degree on the controller, some are much more efficient at part throttle than others, but fwiw I would enjoy some full throttle bursts and between them some lower throttle cooling down periods. In the air you should be ok with that regime.

Personally I do prefer to use a setup I can fly full throttle for 3 minutes flat out as the lower throttle bits seem rather tame after the bursts! If you are in doubt why not fly with short bursts and see how your temps are after the flight. If ok, try longer bursts and so on. That has worked for me when I have been concerned about a particular setup.

Julian
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Old Aug 21, 2009, 02:50 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,304 Posts
56A is cutting it close to the 60A rating of your controller. Some controllers are under-rated. But all controllers are less efficient at reduced power. This causing higher operating temps. Then to throw anothe wrench in the works..if you batt/controller leads are long, you could get a voltage spike. When going from reduced power to full.

So, if you run at reduced power, to conserve batt time or batt temp, the controller gets hot. Try for a 10A extra capacity in the controller, minimum. And on 4s, you may need a seperate BEC or Rx pack.

Fuzz
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Old Aug 21, 2009, 03:39 PM
Registered User
Aylesbury,UK
Joined Apr 2000
983 Posts
I have decided to try the model tomorrow (weather permitting) on a 3 cell pack. This is around 400watts, which will be about 200w/lb. I tried it at full throttle with the nose vertical to see how it felt, and it could just about hold its own weight. I am thinking of trying a wemotec minifan rotor instead, if I can find out the comparitive amp draw on the same wind motor. Hoping it will pull a bit less.
The Eflite package is usually supplied with an Eflite 60A controller, which could be as marginal as my Pentium 60A (on 4S). As far as the bec goes, it is a switching type in the Pentium, which I believe is more efficient than a linear version.
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Old Aug 21, 2009, 04:12 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
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Nothing wrong with 200w/lb. Good luck!

Fuzz
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Old Aug 21, 2009, 05:04 PM
turbonut's Avatar
upland CA
Joined Dec 2004
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As long as you have good cooling air flow I dont think you will have a problem..just dont run WOT for a long time..but on 3s it can fly a whole pack WOT
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Old Aug 24, 2009, 02:26 AM
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Aylesbury,UK
Joined Apr 2000
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Flew the F-18 on saturday, apart from being a bit out of trim it flew really well, not too bad on 3S either. Glad to get it out of the way, put quite a few hours in building it!! Would like to get it up to about 650-700 watts, which should be just about right.
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