Question..Z-power 6s motor what prop?

[Kntt]

I purchased a few of these a couple of years ago to keep my Trex600 electic running. 3 years on and its still doing great on the original motor so i have spare motors i want to use in electric planes.

 

They are outrunners KV1110 made by Z-power and i run them on TP5000 6 cell packs.

Now this is fantastic for the heli great prformance and a 6 min run time when giving it the full 3D.

 

The question is (forgive me if i sound stupid) what prop or model size will this motor drag along?

 

I have spare cells and a couple of 100amp esc so i just needed to know what i could do with them.

 

Many thanks

Kent

 

 

 

 

 

Edited By Kent on 02/01/2012 14:25:29

[Richard Wood]

Hi Kent,

Just a few thoughts here...

 

Do you have any 3 cell packs?

A 3 cell should enable you to use a useful prop size on a 1110 kV motor.

Also do you know the current draw of the motor in the Trex?

The motor's current capacity is an important consideration.

 

Multiply the current by around 11 (V for a 3 cell) to get a power figure &

experiment with a Wattmeter & a few props to get a similar current draw.

100W/lb will be fine for a trainer or lightly loaded sport model.

 

Let us know how it goes.

 

 

 

[Kntt]

Hi Richard

Thanks for the input, yes i have a few 3 cell packs.

I don't know how many watts i am drawing on 6S it looks like i will have to invest in a watt meter.

Thanks for your help i will see what i can come up with.

cheers

Kent

[Daithi O Buitigh]

Completely off-topic Kent, but you need to fix your page on www.qrz.com - it has your QTH in the middle of a very large open field - HI

 

However, as Richard said, all you need to know is the curent being drawn on the 6s pack and multiply that by 23 to give the wattage (W = VA as you mlearnt as a novice license holder)

 

73 de Daithi (GI7OMY)

Edited By Daithi O Buitigh on 15/01/2012 11:51:08

Edited By Daithi O Buitigh on 15/01/2012 11:53:11

[Biggles' Elder Brother - Moderator]

This motor looks like the Z-power Z50 - if so its too powerful for most 3s packs I would suggest - its rated at 50amps!

 

BEB

[Kntt]

Yes BEB you are correct it is a Z50 but what do you think it will pull.I run them on 100amp ESCs. 6s.

I have a watt meter now and i will do some tests when i get a prop adapter this week.

 

Daithi

Google now updated

cheers

Kent

Edited By M0KWR on 15/01/2012 17:54:31

[Biggles' Elder Brother - Moderator]

Well connecting the Z50 to a 6s pack will give you the possibility of just over 1kW of possible power. Erring on the safer side I would suggest you try an 11x7 or 12x6 to start with - but obviously keep a careful eye on the Watts - they shouldn't exceed 50amps at WOT.

 

BEB

 

PS This estimate comes from a new method I've recently developed for selecting electric props so I'd be very interested in the result!

[Kntt]

 

Hi BEB

I will try a couple of props and let you know what i get but what worries me is the prop adapter is a compression spline fitting, are these safe on this size motor?

 

Watts = Volt x Amps. ok but the bit i don't know how to work out is the expected motor RPM on a 22volt pack.

Isn't there a calculation to give you this value based on the KV rating of the motor?

Kent

[Richard Wood]

Hi Kent,

 

A 1110kV motor will theoretically give you 1110 revs per volt.

So a 22V pack for example equates to over 24000 rpm.

In practice, with a prop on the motor, it will be quite a bit less.

Half this for a 3 cell pack of course - which will give useful rpm for turning

a decently sized prop - the size that works best you'll have to find by

experimentation with a Wattmeter - try the ones BEB recommended

for a start off.

A compression 'pinch' type prop adaptor is used on many very highly

powered motors & works well.

 

A 3S, 4500mAH, 20C rated Lipo pack such as this Cod battery will supply

50A easily, so no worries there.

 

 

 

[Kntt]

A 1110kV motor will theoretically give you 1110 revs per volt.

Hi Richard thanks for the info i guessed it was somthing like that.

 

The next quaestion is propeller type!

Do i need special propellers for electric motors or can i user glow engine propellers.

 

I am trying to get everything together for some tests this weekend, i have to make a motor mount next.

 

Cheers

Kent

[Olly P]

They tend to be special light weight props....again Giant cod are the way forward for experimenting.

[Biggles' Elder Brother - Moderator]

You can use IC props - but they are generally of heavier construction than is needed for an electric motor. As Olly says Giant Cod do a big selection of electric props at reasonable prices so you can afford a few to experiment with!

 

BEB

[Kntt]

Hi BEB

Just orderd a selection of props from Giant cod... very cheap and an easy site to use + paypal which i like.

 

11 x 6

11 x 8

12 x 6

12 x 8

13 x 6

13 x 8

 

Should be enough to get an idea.

cheers

Kent

[Biggles' Elder Brother - Moderator]

MOKWR, I'd be interested in the watts and battery used in each of those cases mate! I reckon those should do nicely! You certain should find what you are looking for somewhere in there!

 

BEB

[Olly P]

yeah, an interesting study - I have a couple of projects i might need these power levels for . . . .

[Kntt]

Hi BEB

I will put all my results on here when i have completed the tests... If the weather is good this weekend it may not be till next week Got to get the flying in when you can

 

I am hoping to power a DB Barnstormer with this motor isf all goes well.

I have a few 6 cell TP5000 35c and a few 3 cell TP2200 35c so tests will be based on these packs.

Keep ya posted

Cheers

Kent

[Ben B]

You can use glow props and often people going super fast with Strykers or Funjets do (they're stronger than electric props so don't bend and deform as much when you go silly fast).

 

If you put 6s through a 1100kv motor you'ld probably only want something like a 6*6 prop and even then the pitch speed would be just shy of 150mph.

 

Personally I've just bought a 1400kv motor to run on a 6.5*6.5 on 6s and the aim is a 190mph funjet.... I might well end up going glow prop on that.

[Kntt]

My god Ben that will be hitting some RPM, what speed is the prop rated at?

 

I am looking a a more sedate flier untill i have got to grips with this electic motor stuff.

Kent

[Richard Wood]

Hi Kent,

Two of your 3 cell 2200 packs connected in parallel to form a 3S 4400 mAH

would be best to give good duration (& battery life) in a 50A setup.

 

a DB Barnstormer sounds like a very interesting conversion & should

fly well on 500W or so.

Let us know how your tests go.

 

 

 

[Kntt]

Well i started tests today only to be rained off.

First and only test i managed on a 13x8 prop 3 cell lipo

40.86 max amps

332.6 max watts

2.7 wh

0.310 ah

0'55"

 

first time i have run a prop on an electric motor and its more impressive tha i imagined.

The question is what do you make of these figures. i know i should have dropped a 6 cell pack on as a comparison but rain stopped play.

Cheers

Kent

[Tim Mackey]

Your battery is duff. The important figure you left off is the volts under load, which should be at least 10.5, the figures you give above suggest its only around 8

[Kntt]

Hi Tim 7.6 vm

Yes just checked my scriblings and you are correct.

I am waiting for 4 new packs to arrive then i will crarry out the test again.

thanks for your input

Kent

[Tim Mackey]

Today's new generation packs - with high C rating - should easily hold 3.8V or more.....some of mine are holding 4 volt per cell under quite heavy load.

This will make a huge difference to the power of the setup. It certainly sounds as though your old packs are ready for the bin ( after completely discharging first of course )

[Kntt]

Hi Tim

These are TP2200 and yes i know they are old thee have done 3 years in my SE450 Heli.

I have some 3 cell 3 amp 35c packs on order and some 6 cell 45c packs on order so we should see a difference.

If they arrive this week i will post again next sunday all being well.

thanks again for your input it is appreciated.

cheers

Kent