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Old Nov 07, 2012, 01:49 PM
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Greece, Attica, Athens
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The front cross section (intakes) looks wide. It may be creating too much drag.

My guess is your batteries are not holding up.

The 2700kv motor will want to pull around 60amps.

These small high internal resistance batteries, even at 40C, will not be able to deliver anything more than 50 for long.
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Old Nov 07, 2012, 01:56 PM
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Well for future battery purchases then, what size / c rating should I be going for?
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Old Nov 07, 2012, 02:25 PM
scunna
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45c minimum i would say. edf 's are amp hungry
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Old Nov 07, 2012, 03:33 PM
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Quote:
Originally Posted by stingeragents View Post
Well for future battery purchases then, what size / c rating should I be going for?
The smallest battery that I have which works well(ie provide the 55-65amps needed for a while) with this fan is an "old tech" Zippy 3000mah 4S 40C and low internal resistance "new tech" Gens Ace 2500mah 25-50c(which are an exception since they perform better than their rating).

3300mah 25-50C (Low internal resistance) nano-tech or Gens Ace are also good.

For larger sizes (>3300) the greater than 25C rating is not that important for 4S use and amp requirements of between 55-65.
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Old Nov 07, 2012, 05:55 PM
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Originally Posted by 4stripes View Post
It is kind of like trying to make snoopy's doghouse into a "jet".
Hmmmm......
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Old Nov 08, 2012, 12:29 AM
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Mexico, BC, Mexicali
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More or less this is the criterion that I use, although in some occasions the forced a little bit more. up to 23 c.


The batteries.

The batteries used in ducted fan, preference must be of good quality and a minimum of 30 c. But in 40 c preference.

Even so should only be used to a maximum of 20 c to make sure all engine 3 minutes minimum flight time and a long battery life.

In practice we get 4 minutes or more than flight.

When we use X capacity batteries, will obtain a maximum power of:

With 4s lipo

2200ma, 44. 638 Watts.
2650ma, 53 a. 768 Watts.
3000mA, 60 a. 870 Watts.
3300ma, 66 a. 957 Watts.
4000ma, 80 A. 1,160 Watts.
5000ma, 100A, 1,450 Watts.

Use a lot of power requires many amps, it is easier to increase the voltage by adding more cells.

With 5s Lipo.
2200ma, 44. 792 Watts.
2650ma, 53 a. 954 Watts.
3000mA, 60 A. 1,080 Watts.
3300ma, 66 A. 1,188 Watts.
4000ma, 80 A. 1,440 Watts.
5000ma, 100A, 1,800 Watts.


With 6s Lipo.
2200ma, 44. 968 Watts.
2650ma, 53 A. 1,166 Watts.
3000mA, 60 A. 1,320 Watts.
3300ma, 66 A. 1,452 Watts.
4000ma, 80 A. 1,760 Watts.
5000ma, 100A, 2,200 Watts.


With 8s Lipo.
2200ma, 44 A. 1,276 Watts.
2650ma, 53 A. 1,537 Watts.
3000mA, 60 A. 1,740 Watts.
3300ma, 66 A. 1,914 Watts.
4000ma, 80 A. 2,320 Watts.
5000ma, 100A, 2,900 Watts.


With 10s Lipo.
2200ma, 44 A. 1,606 Watts.
2650ma, 53 A. 1,908 Watts.
3000mA, 60 A. 2,160 Watts.
3300ma, 66 A. 2,376 Watts.
4000ma, 80 A. 2,880 Watt.
5000ma, 100A, 3,600 Watts.

Manuel V.
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Old Nov 08, 2012, 05:50 AM
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Manuel, in ur examples what c rating does that assume.

As far as the draggy airframe on my profile f22, if i built a full fuse one would it be just as draggy as the profile f22? I also just built an edf f15 based off of steve schumates plans. It is bigger than the profile f22 but only weighs an ounce more. It is much slower than my profile f22 though.i scaled it up to 118% so im sure the intakes are much too big. I guess there is a trade off somewhere. I had to do the larger size bird to get my fan to fit in there so the intakes are larger as well. Heres my question. If i purchased a foamy f15 or f22 kit of the same dimensions as the one i built would the intakes be smaller or what? I was looking at some foamy kits to try and compare the intakes and frontal cross sections to get an idea what i need to do
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Old Nov 08, 2012, 11:05 AM
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Bench run CS70 with Eflite Delta V-15 shroud and Tamjets Tailcone

I finally got my CS70 rotor installed in a eflite Delta V-15 housing with an Eflite 3200Kv motor, and overall I am happy with the results. I know this is a higher Kv motor than most use with the CS, but its what I have on hand. I plan to put this setup in my Eflite F-86. The stock numbers for that were around 50 amps and 720 watts installed, so this will be a nice boost with the Woosh sound!

With the new setup and a fresh 4s 25C pack, I pulled around 75 amps at 11124w peak which settled to around 1000w at WOT. I am curious to see how the output will change when installed in the F-86 which has really nice straight through ducting.

Here is the setup:

Eflite Delta-V 15 Shroud
Eflite 3200 Kv BL15 motor
CS70 rotor (dynamically balanced from Tam with his collet, nut, and spinner)
Tamjets CF tailcone and heatsink
Gens Ace 3300mah 4s 25C (I need to try another test run with a higher C pack)
Ice Lite 100 in the tailcone
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Old Nov 08, 2012, 11:10 AM
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Greece, Attica, Athens
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Quote:
Originally Posted by Jetnfast View Post
The stock numbers for that were around 50 amps and 720 watts installed, so this will be a nice boost with the Woosh sound!

With the new setup and a fresh 4s 25C pack, I pulled around 75 amps at 11124w peak which settled to around 1000w at WOT. I am curious to see how the output will change when installed in the F-86 which has really nice straight through ducting.
You are not running an inlet lip so the amps and watts are lower than the expected 90-100Amps for this kv.

I would expect that the amps will rise in the F-86.
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Old Nov 08, 2012, 11:25 AM
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Quote:
Originally Posted by anlucas View Post
You are not running an inlet lip so the amps and watts are lower than the expected 90-100Amps for this kv.

I would expect that the amps will rise in the F-86.
Thanks anlucas, I figured both amp and watts would rise when installed, but wasnt 100% sure. Hopefully I will have installed numbers later today or this weekend.
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Old Nov 08, 2012, 01:05 PM
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Quote:
Originally Posted by stingeragents View Post
Manuel, in ur examples what c rating does that assume.
If I am considering 30 to 40 c batteries.
The batteries.

The batteries used in ducted fan, preference must be of good quality and a minimum of 30 c. But in 40 c preference.

Even so should only be used to a maximum of 20 c to make sure all engine 3 minutes minimum flight time and a long battery life.

In practice we get 4 minutes or more than flight.

Manuel V.
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Old Nov 11, 2012, 07:13 PM
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Hi all I just got my changesun 10 blade and after putting it on the balancer I noticed it's way off wack, the whole fan moves from side to side about a 16th of an inch and shakes the balancer when spinning . Is this par for the course with these things or was mine built on a monday ?
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Old Nov 11, 2012, 07:17 PM
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Quote:
Originally Posted by pencon View Post
Hi all I just got my changesun 10 blade and after putting it on the balancer I noticed it's way off wack, the whole fan moves from side to side about a 16th of an inch and shakes the balancer when spinning . Is this par for the course with these things or was mine built on a monday ?
Yup. It's the adapter. I finally just gave up on mine after much time spend trying to balance and 'fiddle' with getting it to center properly on the shaft. Bottom line: You get what you pay for. If you get one of the better made adapters, you can use the fan, but then it's not cheap any more.
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Old Nov 11, 2012, 07:28 PM
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No I have it on the balancer without the adapter, the adapter shaft hole is too small for my balancer shaft .
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Old Nov 11, 2012, 07:34 PM
Don't Move I've Dropped My Nut
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United States, AL, Huntsville
Joined Feb 2009
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Quote:
Originally Posted by pencon View Post
No I have it on the balancer without the adapter, the adapter shaft hole is too small for my balancer shaft .
You must have a defective fan.....I have two of these, and they required very little to balance
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