micro EDF: how much pitch? - RC Groups
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Apr 25, 2001, 10:18 AM
Registered User

micro EDF: how much pitch?

I would like to mess with indoor EDF, using a KP00 motor and a duct dia. about 1.25".

Any suggestions as to a suitable pitch?, just for starters.


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Apr 25, 2001, 04:25 PM
Registered User
Doc Watson's Avatar

I've thought about this one myself. I would probably start with a midi or mini fan scaled down. Actually a HW-620 which is all I have, although I've got 3 of them!!

Its difficult to make a first 'guess' on this without getting into power curves for the motor and I imagine some complex calculations (which I now very little about).

So I would suggest a 5-6 blade fan with a blade root angle of at least that of a commercial fan unit. In fact thinking aloud, because the hub diameter is smaller it would be better to increase the root angle more than a larger fan. What is the motor radius? this will determine the hub diameter. Also the tip of the blade should be slightly increased.

Just my thoughts on the matter, I'm off back to the building board, where a monster plane is taking shape nicly thankyou very much.

Keep us all informed about your progress.

Apr 27, 2001, 10:31 AM
Registered User

The KP00 motor is a typical can motor, 10 mm. dia with a 1mm. shaft and weighs about 4 gm.
About 1A. on 4 cells is as much as it can take. I wonder if it is the same as the B2 motor?
I've made an EDF300 fan, and was thinking of something along the same lines but smaller.

Oct 16, 2002, 12:43 AM
drbird's Avatar
Just a suggestion but it take more "power" to turn and a five blade then it does an 3 and the added power is nominal especially for anything micro. The GWS EDF-50 shows very little added thrust for the added two blades but drains a battery much quicker. I think anything over three blades for a micro is just wasted power. I would suggest just purchasing an EDF-50 for around $15 and getting a feel for what they have done. Again just my opinion!

Oct 16, 2002, 05:22 AM
Model Designer
keven64's Avatar

What about cropping the tips off a KP-44 rotor ?

Perhaps not, but the average pitch over the length of the shortened blades would be higher . . .

Just a thought . . .


Steve's models are mainly free flight . . . and as such the 4-cell packs are ideal. ( I think I'd be right in saying. )
The EDF-50 requires more cells than that . . .

If I could only get hold of some of the higher voltage ( Kyosho ? ) motors that would fit into my KP-44 fans, I would also have a go with indoor EDF models . . .

The little KP-44 unit would, ( in my 'umble opinion ), be ideal for a tiny ( 18" span ? ) model on some of the small 7- or 8-cell packs.

I could even make one with paper ducting

As it is I'm still stuck with twins. . . in series.

Oct 16, 2002, 10:00 PM
Registered User
nolasco's Avatar

How about a 180-size motor? There are quite a few going around which are used in direct drive planes as well as RC cars. Some are wired "hot" with high RPM and do great on 2-cell LiPoly packs inside a KP44. Current is around 4A. There are also some "tamer" ones that do well with 3-cell LiPoly packs. Current is also around 4A. These latter ones seem to be the "race" motors used on the KP44s Electric Jet Factory used to sell. So far, they all seem to work well on my indoor fan trainer with Kolibri-style wing (see http://www.ezonemag.com/articles/199.../kolibri.shtml for the wing).

I am now also testing a Team Orion Elite stock motor (180-size for Micro RS4 car) on a Wemotec microfan. It looks really promising when powered with a 3-cell LiPoly pack. Current is just a bit over 3A.

A number of folks have also used the Kyosho DMC20BB (available at www.eam.net) on the KP44 with good results as a twin setup. I still have to test one though on my fan trainer.

Jun Nolasco
Last edited by nolasco; Oct 16, 2002 at 10:06 PM.
Oct 17, 2002, 02:00 PM
Model Designer
keven64's Avatar

Thanks very much for all that . . . very informative and now I know what Im looking for.

All I need now is a supplier in the UK . . .