Question about EDFs

[Optionalduck]

I have this edf http://www.hobbyking.com/hobbyking/...lloy_EDF_4800kv_3s_Version_US_Warehouse_.html
with a 25A ESC and its not producing enough thrust (i know i should've went for the 4s version). So would it be ok if I installed a 10 blade fan? How would that effect the amp draw and could the motor handle a 4s battery even if its rated for 3s?

 

[Jaxx]

You will see an increase in current draw if you install a 10 blade fan. A 4S would probably burn up the motor.

 

[quorneng]

I suppose the question is "not enough thrust" for what?

 

[LitterBug]

There is not an equal increase in thrust vs number of blades and you may see no increase at all. Higher blade count fans have a lower angle of attack. You will probably need a higher KV motor and/or a 4S motor.

Cheers!
LitterBug

 

[Optionalduck]

I suppose the question is "not enough thrust" for what?

for a plane I designed that is a bit too big for this edf.

 

[quorneng]

If you know how close you were to the recommended max amp figure (18A) with the 5 blade it would give you an idea whether the higher draw of a 10 blade was a possibility.
A 10 blade fan is very likely to be less efficient than a 5 blade so the increase in current will not generate the same increase in thrust.

a bit too big for this edf

For EDFs in particular the thrust to weight ratio is a more important factor than size alone. Big but light can work well with a relatively low power EDF.