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Other › Smaller pinions for a Logo 20?
08-11-2007 07:22 AM  10 years agoPost 1
monterey_tip

rrVeteran

Monterey, Ca - USA

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Does anyone make a smaller pinion than the 10T for a Logo 20? I'm getting too much head speed and could go for a 8 or 9T pinion.

Tip

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08-11-2007 03:45 PM  10 years agoPost 2
SR71

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Hillsboro, Oregon -​USA

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What kind of motor, ESC and head speed are you seeing with a 10T?

As a reference point, my Logo20 runs Pletti 300/25/A3, 10T, CC HV85(HI Gov), (4s4p * 2) with HS ~ 1560.

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08-11-2007 05:18 PM  10 years agoPost 3
monterey_tip

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Monterey, Ca - USA

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Pleti 300/30/A3
Kontronik 55-10-32 Governer mode
10T
10s lipos
720mm blades

I haven't tached it lately, but it is probably in the 1800 range. I think I would like it in the 15-1600 range.

I can dial it down on the percentages to about 65-70% and the ESC doesn't get hot, but I thought that was a bad way to control the headspeed.

Thx,
Tip

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08-11-2007 05:53 PM  10 years agoPost 4
SR71

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Hillsboro, Oregon -​USA

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It is also my understanding that dialing down ESC % < 80% is entering into a grey area where an ESC can get smokin hot; good news yours doesn't. If the ESC is not hot and you are getting the flight times you want, then maybe it's OK?

An often suggested achieving the desired HS approach is to walk down the gearing path, which you already are.

Using your setup the rotor speed 'estimator' @
http://www.e-helis.com/helicalc.php yields theoretical Max HS of 1758 RPM using 10T pinion with the 138T main.
80% max = 1406
85% = 1494
90% = 1582

Using the 96T main with 10T pinion yields a max HS = 2528 RPM.

In my 'limited' testing the RS estimator is fairly accurate for max HS; 'under load' figures vary widely.

If your not using the 138T main (logo part #3000), $13.50 will change your landscape.

My gearing adventures lead to using an 11T pinion as the bird 'feels/sounds' comfortable around 1700 HS @ 85% ESC using 600mm blades; your mileage will vary using longer blades.
BTW, did you stretch to a Logo 24 boom in order to run the 720mm blades?
Is AP the application?

Enjoy.

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08-11-2007 06:45 PM  10 years agoPost 5
monterey_tip

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Monterey, Ca - USA

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If the ESC is not hot and you are getting the flight times you want, then maybe it's OK?
That's what I was thinking, but I really don't want to smoke my ESC.
Maybe the Kontronik can handle it??

I just counted the main gear and it is 138T.
BTW, did you stretch to a Logo 24 boom in order to run the 720mm blades?
Is AP the application?
I did stretch it for AP.

It flys really well at about 65%-70% power and I'm guessing somewhere around 1600rpm and like you said, sounds and feels comfortable.

When I go with 80% it sounds really fast and bounces around too much, which would probably be good for 3d. The sound makes me cower a little like a blade is going to come shooting at me!!

Thx,
Tip

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08-11-2007 08:49 PM  10 years agoPost 6
TOSH

rrElite Veteran

UK.Peterborough

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Not the best of photos but at the Masters the team had some big heatsinks stuck to their ESCs. Could be better than a smalle pinion.

Flybars. Who needs `em.

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08-11-2007 08:58 PM  10 years agoPost 7
monterey_tip

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Monterey, Ca - USA

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Thx Tosh,
I might just go that way...especially since the ESC isn't very hot to begin with...then again, I'm wondering if it would be more efficient with longer run times and more torque to swing the larger blades if I had a smaller pinon.

I see there is a Century pinion that is 9T and works with module 1.0 Logos:[url=http://www.fxaeromodels.com/product_info.php?products_id=2864]

But I assume that is the 96T main gear, right? I don't really know what what module I have now with the 138T main. I assume the module is the gear spacing??

Tip

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08-11-2007 09:07 PM  10 years agoPost 8
TOSH

rrElite Veteran

UK.Peterborough

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I assume the module is the gear spacing??
Yup, mod l= lmm
mod.7= .7mm
mod.5= .5mm

l think the 138T main is mod.7 from the logo 14.

Flybars. Who needs `em.

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08-12-2007 07:08 AM  10 years agoPost 9
monterey_tip

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Monterey, Ca - USA

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Thx for clearing that up Tosh. I always wondered what the numbers meant.

I flew today for about 6 1/2 mins at 65% (No Camera weight)
and put back about 2300ma on 10s, so I guess it is pretty efficient. I felt the ESC as soon as I landed and it was barely warm. The motor fins and lipos were a little warm, but not hot.

I have just read so many threads about how the power needs to be above 80% to avoid problems with the ESC and for max efficiency. Should I not worry about it and keep it the way it is?

Tip

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08-12-2007 07:28 AM  10 years agoPost 10
OICU812

rrMaster

Edson, Alberta,​Canada

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I have just read so many threads about how the power needs to be above 80% to avoid problems with the ESC and for max efficiency. Should I not worry about it and keep it the way it is?
This is the case with Castle Creations, Jeti, and a few others. However Kontrink ESCs' work entirely different in the way they regulate voltage. Having a % even as low as 65% is no big deal in the ways of heat and abuse.

...Once upon a time there were Nitros, flybars and frequency pins...

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08-12-2007 09:40 AM  10 years agoPost 11
TOSH

rrElite Veteran

UK.Peterborough

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. Should I not worry about it and keep it the way it is?
l would carry on as you are. lt all sounds good to me.

Flybars. Who needs `em.

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08-12-2007 04:28 PM  10 years agoPost 12
monterey_tip

rrVeteran

Monterey, Ca - USA

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Thanks guys. Now I can find something else to worry about...wait...forget about it...I'll just go fly!!

Tip

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