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Old May 22, 2001, 07:51 AM
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Jeti Phasor motors geared?

Anyone with a jeti phasor motor know if you can fit a gearbox,..i.e. does it have mounting holes up front,..and if so, what's the spacing equivalent to?
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Old May 22, 2001, 07:57 AM
jrb
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Your trusty GP box will fit!

The issue becomes putting a 48 pitch pinion on the 5mm shaft; always been an issue with the Aveox 14xx motors.

A Team Losi 17T would hog out nicely to 5mm; but up or down (beyond a couple) on teeth and there not much left when drilled out to 5mm.

Maxcim/MEC drill out pinions to 3/16"; but say they won't do 5mm.
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Old May 22, 2001, 09:06 AM
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I just purchased a 2:1 Kruse gearbox for my Aveox 1412. It has the 5mm pinion gear. (HLKR5310).

There is also a Velcom 2:1 gearbox that is available with 5mm pinion shaft as shown in Hobby Lobby http://www.hobby-lobby.com/drives.htm
I don't know if the hole spacing is right for the Phasor but I'd bet it is.

Also available are the Aveox and Robbe planetaries but the gear ratios are for higher RPM motors than the Jeti Phasors are designed for.


[This message has been edited by Gerald (edited 05-22-2001).]
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Old May 22, 2001, 09:37 AM
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Sure they'll work if your happy with 2:1; I think a different ratio would yeild better performance though.
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Old May 22, 2001, 02:05 PM
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Quote:
Originally posted by jrb:
Sure they'll work if your happy with 2:1; I think a different ratio would yeild better performance though.
Such as? Can you explain what other ratios would be better and why?

These motors are designed for direct drive applications. It seems to me that 2:1 is already about as much as you'd ever need. I hear that the Jeti motors have a lower RPM limit than other brushless motors due to their lower RPM/Volt constant and not being as finely balanced.
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Old May 22, 2001, 03:37 PM
Rod
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I am awaiting shipment of a Jeti motor from New Creations. I was told that a 2:1 ratio is OK, but not to go any higher as the Jeti motors are not intended (or built) to run at the higher speeds that a high ratio gearbox will allow.
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Old May 22, 2001, 04:01 PM
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Gerald,

The advantage of the Velkom gearboxes (as with several others in the planetary and other higher end genres) is the fact that they are innerdriven. This means you don't have to get the Phasor reversed to run it (a pain on brushless).

The gear ratio depends on your intended use. In general, the higher the ratio, the more efficient the setup due to spinning a larger prop. But think about it - you can't go too high or you won't have enough RPM's at the prop to generate enough prop pitch speed to fly (it would probably make a nice ceiling fan though), or the prop would have to be to big for your plane to support. It also depends on the RPM of the motor at the voltage you apply (there are mechanical limits there as well, to many RPM's will spin the armature apart). Too little ratio and you aren't getting anything back for the energy you lose in the gear meshing and other mechanical loses (resistance). In "general", the higher the motor Kv, the higher the gear ratio you use.

So Rod is right, the Phasors are not high RPM rated motors (pretty low Kv since they are designed for direct drive in the first place. I'd guess at somewhere between 1.75:1 and 2.5:1 at the range depending on your intended application and prop requirements. With a gearbox, you can probably push the motor a little (ie, 18 cells instead of 16, or 12 instead of 10 - etc).

You really have to take it case by case for specific motors, planes, application, and personal flying preferences/skills.

The only problem with gearboxes and brushless motors is brushless motors have a high torque lock or cogging effect (hard to spin freely). This is especially true if any braking system is used. Such hard stops are hard on gears - hence you need to use a quality gearbox (no cheap nylon or plastic gears used here).

Hope at least some of that helps
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Old May 22, 2001, 05:12 PM
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>This means you don't have to get the Phasor >reversed to run it (a pain on brushless).

Inner-driven and planetary gearboxes are great for mounting reasons, but reversing the Phasor motors is about as easy as it can get - simply change the connection order of any two of the three wires.
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Old May 23, 2001, 09:17 AM
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Have you noticed that all the Jeti BL motor wires are black? Which way is forward, which way is reversed? As stated above swap them until the prop turns right!

Nylon gear Ė Maxcim/MEC have been using a nylon spur gear for years with their brushless systems. May even offer just a bit of cushion/safety in an unfortunate situation.

Also, BL & GB have been used very successfully for as long as theyíve been used in electric flight.

The real issue at this point is how well do these run and what are their real specís versus whatís listed (and missing Ė max rpm?).

Notice that the 45/3 nearly matches the specís of the Aveox 1415/3Y, but w/o knowing its ratings we donít know if it will do the same for Ĺ the $.

The 30/3 looks like it compete with the Maxcim ďYĒ and 1409/3Y, but ?? Itís a lot better price and even has a bigger Km; should be able to handle some more power. Even with a 25,000 rpm limit and 18-20 cells w/ 3 to 3.5 ratio puts this in nearly the .60 range at a very nice price.

A bit more clarity on the specís and some experience would be great.
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Old May 23, 2001, 11:47 AM
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I understood that you can't run the Jeti Phasor motor geared due to the "soft start" feature of the controler. Has anyone tried this yet?

Marcel.
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Old May 23, 2001, 11:59 AM
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"Soft Start" would be a plus for use w/GB; wouldn't it?

How about using their motors with an ESC that has proven GB performance, i.e. Kontronik?

I have reviewd the the Jeti BL motor and ESC sheets that are supplied with the motors and find no reference to "soft start" or an rpm limit.

I would seem to me that a motor could have a different rpm limit for GB & direct applications, and that GB applications couls have a higher limit since the dynamic imbalance laod would be far less that that achieved with a directly drive prop.

I'm very lieky to get a 30/3 and give it a try with my 3SLB40-6-12 and 3SL70-6-18; I'll report the results here if I go for it.
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Old May 24, 2001, 09:08 PM
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I saw the medium size Jeti fly during a limted motor run contest in Atlanta. (King Peach Event.) LA Johnson from Hobby Lobby was there and ran a 12 X 8 prop at 5800 RPM direct drive in a very light old timer called a "kerswap" or something like that. The motor can easily be revesed by swapping any two wires. The draw back to using a gearbox will be the RPM constants are low for these motors. The medium size motor has a 1200 RPM/volt constant and the largest motor is 800 RPM/volt. Besides, when a direct drive motor can turn that big of a prop, what more can you ask for. He said that the largest motor will turn a prop in the neighbor hood of 13-14 in. range but I didn't get to see that run. His airplane did quite well in the Class A Oldtimer on a 1 minute motor run. He using 7 800AR's and only drawing about 28.5 Amps. Looks like a good sport motor.
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Old May 25, 2001, 07:46 AM
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Guys, the only stated limitation of these motors which make themnon Gb freindly is rpm.

Compare the MotoCalc specs of the 45-3 and an Aveox 1415/3Y -- they are identical!! Even the 1415 data on Aveox site show about the same direct drive performance.

What should really impress you about this is the fact that the 1415/3Y w/3.71 GB flies the Hangar 9 IMAA ARFs! Specifically the PT-19 (30 cells) & Edge 540 (32 cells) w/16x10 APC"E". The motor revs are just below 25k, and that would be $149 vs. $275, if Jeti would support 25k rpm in GB applications.

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