700-MX Winding Project

[powercroco]

I don't know your american screw system - I use a 1,4mm boring and cut a metric M2 (2mm outside diameter) thread in.
the same makes kontronik in pyro, but they use a screw with head.

[ZuvieleTeile]

I got all the metric drill bits and taps. . .
All imported from Germany.

First I didn't know, how Kontronik does it, because the bearing usually sits right on top of the holding tube inside the stator. And there is no room for a screw head.
But then I saw a pic. The Pyro holding tube extends through the whole stator and the bearing sits right inside.
The screw works as twist-lock and the head secures also the bearing.
In case of the 700-MX, that wouldn't work, so I have to take a pin or a grub screw.
I still don't know, if I should exchange the shaft once I am on it, to a Scorpion shaft.
Easier to remove and reinstall.
With the Align shaft it is tough to adjust the play. . . and I would like to see a shim underneath the bottom bearing, where the inner race sits right on the aluminum.

[Stolla]

Zt on an el cheapo like the align just throw it all back with the pin and stock shaft, it's not as if youre gonna want to take it apart again, leave the fancy stuff for your future rewinds let's get this thing done! Personally i would only spend serious time on a motor if i can get the happy looking crocodile on the bell!

[Stolla]

Question to you Ralph, i want to rewind my mx for efp(extended flight project) TDR. Since i'm going to use the jive, how much lower will the kv have to be than the normal 510 or so to show a marked improvement in flight times all factors being equal. I'm a little concerned if i go for let's say 450 kv the difference is marginal and can be offset by the ability of the jive to run partial throttle on the 510 rather.
I'm asking for a "gut feel" opinion i know you are a master at formulas and such but since i have no real specs i'm in the dark. I took notice of the stronger magnets for bringing kv down but too inaccessible to consider at this point. Thinnest wire i have is 1.12, is it worth it to go 1.12 max wire i can fit in the slots?
Cheers!

[GMAURO]

Originally Posted by Stolla

Question to you Ralph, i want to rewind my mx for efp(extended flight project) TDR. Since i'm going to use the jive, how much lower will the kv have to be than the normal 510 or so to show a marked improvement in flight times all factors being equal. I'm a little concerned if i go for let's say 450 kv the difference is marginal and can be offset by the ability of the jive to run partial throttle on the 510 rather.
I'm asking for a "gut feel" opinion i know you are a master at formulas and such but since i have no real specs i'm in the dark. I took notice of the stronger magnets for bringing kv down but too inaccessible to consider at this point. Thinnest wire i have is 1.12, is it worth it to go 1.12 max wire i can fit in the slots?
Cheers!

Hi Hermann, the stator of 700 MX have a big space into the slot for chopper wire.... with 1.12 cable probably is easy to drop the Kv under the 380-400 Kv.

[Stolla]

Ah ok thnx MAuro, that sounds if it could work then, will pull it apart weekend and check it out
Cheers

[powercroco]

Gmauro is imho right.

[Stolla]

Great thnx Ralph, will see how many turns i can hammer into the slots, then post the findings
Cheers

[Stolla]

Well i decided against slow kv for align as the 5020 didnt work out too well on 500 kv range thermaling my jive so i quickly did mx in 500 kv range 7+7 1.32yy, well, not done yet, so much for quickly .....,but only the soldering testing etc so hard work is done. In retrospect 1.25 would have been better fit and cooling. ITs a very nice motor to rewind, only problem is you need more turns in the slot compared to 4035 (6+5 vs 7+7) so mx is actually harder to wind except of course if you do the stronger magnets.
Ralph where to get stronger magnets for them? and what glue do you use for the magnets?
Cheers

[powercroco]

I use scorpion replacement magnets.
in case it is needed, I shorten them.
for 700mx we have used the magnets from 4035 V3.
for gluing them we use loctite 648 or 620 and a special milled from POM tool to get equal distances.

[ZuvieleTeile]

Sure looks good, your winding. . .
So, which winding method did you use.
As far as I can see you did not use the zick-zack with the outside jump?

[Stolla]

Originally Posted by powercroco

I use scorpion replacement magnets.
in case it is needed, I shorten them.
for 700mx we have used the magnets from 4035 V3.
for gluing them we use loctite 648 or 620 and a special milled from POM tool to get equal distances.

Thanks Ralph, Will see if i can get hold of some for my next project.
ZT as you know I like the in-out version espescially if i have to add windings as you end up in the middle anyway.

[Stolla]

MAyday MAyday Ralph please come to rescue, so i ran my mx 7+7 on fusion hawk. esc calibrated to run 520 kv on the 5020 that ran 510 with p/jazz so i know esc is right.
Problem i have is i get only 475 kv instead of the 510kv or so i was hoping for. Now my question being should i pull turns from the slots or leave as is then just use a bigger pinion on the heli to get higher headspeed? What will give me the best motor, in this instance. If by removing wire will give me better performance i'd say perhaps 6+6?

[powercroco]

I would shorten the winding 1 turn each second tooth. then test with long ends for n spec.
(475/510*14= 13 = (6+7)

btw: with the stronger magnets we had:

(from rewinding site)
6+6x1,6YY ergibt eine ns von 500u/V.

so it seems to me, all is in the right range!

to use a bigger pinion is only a good way, if the motor has power without end - we did this with 4540 (4+3x1,8YY) on tdr up to 16T pinion. this motor has enough torque also for 17T pinion......
but in case of the align I think, the better idea is the first one.

and it is also easy to do I think.

[ZuvieleTeile]

Since Stolla did not change the magnets, I suppose, the 7+7 YY should be perfect.
So, I am wondering, why he has only 475 Kv. . .
When the guys in Germany rewound their 700MX, they used 1.25 mm and 7+7 and this resulted in a KV of 510.
Only after changing the magnets, they had to reduce to 6+6, in order to get 500 again.

[Stolla]

Originally Posted by powercroco

I would shorten the winding 1 turn each second tooth. then test with long ends for n spec.
(475/510*14= 13 = (6+7)

btw: with the stronger magnets we had:


so it seems to me, all is in the right range!

to use a bigger pinion is only a good way, if the motor has power without end - we did this with 4540 (4+3x1,8YY) on tdr up to 16T pinion. this motor has enough torque also for 17T pinion......
but in case of the align I think, the better idea is the first one.

and it is also easy to do I think.

Thanks, Ralph, I removed one on the long leads but motor sounded funny, maybe my imagination though, so I removed one on each slot, now kv is 550 on fusion hawk, so should be lower on pjazz, I think very close to the pyro with 6+ 6 which ran 525kv on pjazz. For 510 range then it should be 6+ 7. I'm happy as it's going in my e 720 which I want to run at 2200 on 10:1 gearing.
Although highly unlikely is there a possibility that my kv is slower because of the in-out method I use with both wires exiting on the outside, then having to bend back to inside a little more copper?

[powercroco]

Originally Posted by Stolla

Although highly unlikely is there a possibility that my kv is slower because of the in-out method I use with both wires exiting on the outside, then having to bend back to inside a little more copper?

no. no way.

[flerpie]

Originally Posted by powercroco

for gluing them we use loctite 648 or 620 and a special milled from POM tool to get equal distances.

I'd really like to see that tool. Please post a pic.

The loctite 648 docs say that it will fluoresce.
Do you inspect the motor with UV light ?

Thx.

[GMAURO]

Originally Posted by powercroco

I use scorpion replacement magnets.
in case it is needed, I shorten them.
for 700mx we have used the magnets from 4035 V3.
for gluing them we use loctite 648 or 620 and a special milled from POM tool to get equal distances.

hi Ralph, what tipe of neodym magnet are used in scorpion motors? Or what type is preferred? For example 40uh, is good for our brushless motors?
Thanks mauro

[powercroco]

Originally Posted by GMAURO

hi Ralph, what tipe of neodym magnet are used in scorpion motors? Or what type is preferred? For example 40uh, is good for our brushless motors?
Thanks mauro

scorpion magnets have been described as N50EH.
if they are really N50 a cannot measure, but definately the hold their complete magnetism up to 180°C - this have I hested some times.

N40 UH also will be okay of course.