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Old Oct 30, 2002, 03:25 PM
Registered User
Helena, MT
Joined Sep 2002
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Spur Gear / MEC Gear Box

I'm converting a Sig 4*40 to electric. I'm powering it with a Mega Motor hooked to a MEC Gear Box. The Spur Gear that MEC supplies has a set screw in it, and I would much prefer to have a Spur Gear that presses on. My Mega Motor has a 5 MM shaft. Does anyone out there know of someone that could supply me with a Spur Gear with a 5 MM hole in it that would press on my motor? The Spur gear I have has 18 teeth, but I don't know what the pitch is. Thanks.

Scott
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Old Oct 30, 2002, 05:21 PM
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Rutherfordton, North Carolina, United States
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Scott,
The only ones I have seen for the MEC box and motors with 5mm shafts are held with a set screw. Suggest you file a flat spot on the motor shaft and treat it as a permanent install with some Locktite 640 or similar (both on the set screw and the motor shaft to pinion fit). If you need to get it off later you can press it off.
If you really want a press on pinion, then you can switch to an Astro Flight Superbox ( Mega 22/20 and 22/30 series ) 3.69:1 ratio with a press on pinion for 5mm shaft from Kirk Massey @ New Creations. You get those nice machine cut helical gears and that sweet whine they make when in operation too
Ed
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Old Oct 31, 2002, 08:30 AM
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Re: Spur Gear / MEC Gear Box

Quote:
Originally posted by WellDriller
I'm converting a Sig 4*40 to electric. I'm powering it with a Mega Motor hooked to a MEC Gear Box. The Spur Gear that MEC supplies has a set screw in it, and I would much prefer to have a Spur Gear that presses on. Scott
Are you referring to the pinion gear that fits on the motor shaft?

If is is the pinion the 5mm pinions that are supplied by MEC are a bit of a pain because they only contact 1/2 the spur gear and if you are not carefull with aligning it the set screw can come in contact with the spur gear teeth because it sticks up too far.

I had to grind a pretty deep flat spot in my Mega 22/20/2 and 22/30/2 motors to make them line up in the center of the spur and have the set screw screw in far enough so it's flush with the pinion. You can also grind the set screw down a little. I did that and was able to still screw it in OK. I use a little Loctite blue and I have to use a pinion puller to get it off after taking the set screw out.

Here is what it looks like on the 22/20/2 in my E3D.

Kelvin
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Old Oct 31, 2002, 08:45 AM
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Quote:
Originally posted by Ed Lyerly
Scott,

If you really want a press on pinion, then you can switch to an Astro Flight Superbox ( Mega 22/20 and 22/30 series ) 3.69:1 ratio with a press on pinion for 5mm shaft from Kirk Massey @ New Creations. You get those nice machine cut helical gears and that sweet whine they make when in operation too
Ed
I went to the Astroflight website and they only showed their Cobalt motors with the gearbox. I didn't see anything about a Mega series. With these gearboxes are you stuck with the gear ratio, 3.69? Can you swap out pinions to change gear ratios? I may want to try a different gearbox on my Mega 22/30/2 LT25. I'm currently running it using 4:1 with a 14x10 on 16 cells. With 3.69 I could change the prop to a 14x7 I guess. Thanks

Kelvin
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Old Oct 31, 2002, 09:00 AM
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Quote:
Originally posted by kelvin


I went to the Astroflight website and they only showed their Cobalt motors with the gearbox. I didn't see anything about a Mega series. With these gearboxes are you stuck with the gear ratio, 3.69? Can you swap out pinions to change gear ratios? I may want to try a different gearbox on my Mega 22/30/2 LT25. I'm currently running it using 4:1 with a 14x10 on 16 cells. With 3.69 I could change the prop to a 14x7 I guess. Thanks

Kelvin
Go to Kirk Massey @ New Creations as stated in the post. Part #
AF712A = 3.69:1 Superbox with a 5mm press on pinion (originally made for Axeox 14XX motors but will bolt up to Mega 22/20's and 22/30's with just a little filing to clear the Mega front bearing).
You can't change the gear ratio. You can get 2.38:1 with AF702A, but that's a different gearbox.
If you have the Astro gearbox already, you can get just the 5mm press on pinion gears from Kirk.
Ed
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Old Oct 31, 2002, 09:48 AM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
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Hi Scott,

Typically, we call the larger gear that drives the prop the spur gear and the smaller gear that attaches to the motor shaft the pinion gear.

For your 18T pinion gear, you'll find that by using some Locktite on the threads, and, snugging it gently with a hex wrench, that you will not have any problems.

We run 20" props with this setup on the 16T, 18T, and 20T pinions without a problem. The advantage of the set screw is easier replacement for fine tuning your performance.

Good luck!
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Old Nov 01, 2002, 11:26 AM
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Helena, MT
Joined Sep 2002
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Pinion Gear / 5MM Hole

Hi Fellas,

Thanks for your input. I guess you all need to hear the rest of the story. I originally ordered a AstroFlight 713 gear box with a pinion for a 5MM shaft in August from AstroFlight. I started trying to check on my order around the first of October. AstroFlight won't answer their phones and they won't answer their E-mails in a timely manner. Their customer service sucks!! Anyway, I finally got hold of them and they tell me they can't supply a 5MM hole in the pinion and cancelled my order after I waited 2 months for their gear box.

I called Pete at MEC and in 3 days I had a gear box on my front door step. MEC customer service is Excellent. I ground a grove in my motor shaft and installed the pinion gear with blue loctite. I also had to grind down the set screw a little so that it wouldn't hit the large gear. That motor shaft is harrrrrrrd. You don't file a spot on it, you have to grind it. It just concerns me a little that the pinion is only 1/2 the width of the larger gear because they machined away part of the gear to accomadate the set screw. That is why I would like to find a pinion that will press on so that the full width of the pinion will contact the larger gear. Other than that, Pete with MEC got me squared away in good shape.

Scott
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Old Nov 01, 2002, 12:29 PM
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Amarillo Intl, Texas, United States
Joined Dec 2001
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other options

I too have recently gotten an MEC superbox, but I do not know if it uses the "standard" 48pitch tooth profile. It does appear to, but I'm not certain. Somebody else may be able to chime in on this. I don't want to suggest that you "rig something up" but you may want to look at pinions from Robinson Racing or even from Losi (my preference) at your local hobby shop that carries stuff for the electric car guys. They have an 1/8" id hole, but can be easily drilled out to 5mm if they're enough OD on the gear. The Losi pinions have especially nice tooth profiles and run very quiet.
An added benefit is that they're wide at the toothed contact area.... 0.2" or so (a little more contact than the MEC pinion at least, I can mic it to be more precise) If you do decide to machine a 5mm hole in them, then the setscrew won't have many threads left to seat in....but you're using loctite as a secondary measure.

The pinions typically go for around $3 (worth the price of experimentation!). Finding a 5mm drill bit is probably more of a pain than finding pinions.
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Old Nov 01, 2002, 12:45 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
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Question for you MEC GB users:

I keep hearing that for planes like the e3d this is a better box then the gd600 box because it won't strip spur gears on prop strikes.

I see from the pic in this post that the MEC box also has a plastic spur gear, so why don't they strip?

I am considering using one of these in the 6:1 ratio, but if its going to strip too, I might as well keep using the gd600 at 4.6:1.


Dean in Milwaukee
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Old Nov 01, 2002, 12:50 PM
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With the endoplasma or Hacker C40,.. you'll be using the 10-tooth press-on gear (because those two motors have 1/8" shafts), and that pinion is full-width on the superbox spur gear,.. so i don't think you'll see any of the problems like people are having with the 5mm shaft motors using the narrow pinions. I've certainly had none,..of course,.. I rarely have a problem with a GD600 either,.. so I'm probalby not a good indicator
I've heard that the IKARUS pinions for the echo 8 are 48 pitch. I can't confirm that, maybe someone else can,.. but they just might be wider than the car pinions. Anyone here have an echo-8, and a superbox?
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Old Nov 01, 2002, 12:52 PM
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Quote:
Originally posted by DeaninMilwaukee
Question for you MEC GB users:

I keep hearing that for planes like the e3d this is a better box then the gd600 box because it won't strip spur gears on prop strikes.

I see from the pic in this post that the MEC box also has a plastic spur gear, so why don't they strip?
Dean in Milwaukee
Dean,
Thicker gears and what appears to be a tougher material is the difference. It's just a more robust construction.
Ed
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Old Nov 01, 2002, 01:12 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
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Hey thanks Ed!

Another question for you regarding my 48 oz 500 sq/in pattern plane.

Trying to figure the best motorcalc setup going from 8 cells to 10, and weight will climb 4 oz.

Now: 8 cp2400 / 3.8:1 / 12x8 apc-e 31 amps, 46 oz thrust 52 mph ps.

new: 10 cp2400 or 3000 nimh / 6:1 / 13x10 26 amps 49 oz thrust, 54 mph ps.

Motocalc says climb from 1400 to 1600 FPM, top speed up from 51 to 56.

Does this sound to you like a good combo for pattern flying, or would you go to a higher draw/thrust combo and throttle back to extend flight times? I was getting 5 minutes on average before.

The goal here is to improve both flight times and get a bit more power for those really big loops.


Thanks,
Dean in Milwaukee
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Old Nov 01, 2002, 01:23 PM
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looks like it will be a good trade (weight/performance) dean, however, if it's a pattern style plane (without a thick wing), I'd actually use the power increase for pitch speed versus thrust. Maybe go to an 11X10 and gear appropriately for your current requirements. for good pattern performance, you actually want more speed, and the prop to "bite" at a higher speed. The higher pitch will actually give you more thrust for larger loops, at flying speed, although the static thrust might be a bit lower. I also have a rule of thumb regarding flight time,.. the left stick determines flight time and the amperage determines power . One plane I have drawing 58 amps static,.. and get 6 to 8 minutes flight times. The math would indicate it should only fly half that long (left stick determines flight time ) . Also,..you might want to try the new sanyo 2600's. I actually get longer flights with them than the 3000's. they don't drop capacity under the high loads we abuse them with. The 3000's actually deliver less capacity than the new 2600's in our realm of use. they also deliver higher voltage under load than even the CP2400's,.. so power is up to boot. I have 30 of them now and another 60 on order. I'm impressed with this cell, to say the least.
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Old Nov 01, 2002, 01:30 PM
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Quote:
Originally posted by GWRIGHT

I've heard that the IKARUS pinions for the echo 8 are 48 pitch. I can't confirm that, maybe someone else can,.. but they just might be wider than the car pinions. Anyone here have an echo-8, and a superbox?
This picture shows the Ikarus and MEC pinions, the Ikarus being the larger of the two. Both are 5mm. Notice how the Ikarus teeth flare near the set screw end. The trick is aligning the spur gear so the edge of it doesn't contact the curve portion of the pinion gear.

Kelvin
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Old Nov 01, 2002, 01:36 PM
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Here is the Ikarus gear on the Mega 22/20/2 motor. To get the gear to line up correctly with the spur I had to move the pinion all the way to the end. Even then it looked like the forward edge of the spur was riding on the the up curve of the pinion a little bit. That is why I went back to the MEC gear. Ikarus pinoins are in the Eco helicoptor parts at Hobby-Lobby. They are considerably cheaper than the MEC gears. I think the MEC gear teeth seem to mess a little better than the Ikarus so by eyeballing them through a magnifying glass.

Kelvin
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