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Old Jul 05, 2013, 05:21 PM
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Question
EDFs and balancing

So I was running the motor without fan and noticed the collet wobbling. I said to mysef "What's the point in having a nicely balanced fan when the thing it's mounted to is of such crap engineering quality you can actually see how off-centre it is?"

I did notice the 3mm motor shaft on this Lander unit was turned down to 2.37mm, but being new to EDFs, and not knowing too much about fan technology, I need to get me a properly engineered collet, or some other method of securing said fan. Any suggestions?
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Old Jul 05, 2013, 05:51 PM
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Common problem with lot of adaptors, you need precise and tight fit, for smooth running unit, they are avail. or if you have access to lathe get someone to make one up. If the tolerance isn't too big you can always try and fiddle to get it run reasonably true carefully tightening opposite grab screws while using mid strength locktite, Good luck Joe.
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Old Jul 05, 2013, 06:40 PM
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Originally Posted by jofro View Post
Common problem with lot of adaptors, you need precise and tight fit, for smooth running unit...Good luck Joe.
I remember when I first started with elec planes and feeling so frustrated trying to get prop savers to fit various motors, now it seems I have to go through the same sort of dumb issues with EDFs. I really wish I had my own lathe, especially as this Lander motor has a strange shaft size. They've actually turned it down to fit the naff adapter from the 3mm standard shaft dia., and so only naff Lander adaptors will fit? Is that dumb or what? I won't be buying Lander units in future, that's for sure.

Sorry to moan, but I'm wondering if all manufacturers are the same, or is there any such thing as standard? I suppose I'm going to have the same sort of headaches with fans and mount hole spacings too...I should have stuck to props.
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Old Jul 05, 2013, 09:25 PM
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Originally Posted by FlyBoy20 View Post
I remember when I first started with elec planes and feeling so frustrated trying to get prop savers to fit various motors, now it seems I have to go through the same sort of dumb issues with EDFs. I really wish I had my own lathe, especially as this Lander motor has a strange shaft size. They've actually turned it down to fit the naff adapter from the 3mm standard shaft dia., and so only naff Lander adaptors will fit? Is that dumb or what? I won't be buying Lander units in future, that's for sure.

Sorry to moan, but I'm wondering if all manufacturers are the same, or is there any such thing as standard? I suppose I'm going to have the same sort of headaches with fans and mount hole spacings too...I should have stuck to props.
The Wemotec 70mm EDFs have the most precision (tru-est running) shaft adaptors out there (for a composite EDF rotor). Motor shafts must either be 3.17mm or 4mm.
The bore for the motor shaft is slightly undersized, and requires heating with a gas stove or micro torch, before slipping onto the motor shaft. The set screws can then be installed (after cooling) with thread lock, and thier order of tightening adjusted to negate and slight runout you might feel when running the motor in a vise and feeling the shaft adaptor (rotor mounting area) with your finger. No flat is required on the motor. (there should NOT be a flat on the shaft)
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Old Jul 06, 2013, 12:36 AM
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Originally Posted by FlyBoy20 View Post
I remember when I first started with elec planes and feeling so frustrated trying to get prop savers to fit various motors, now it seems I have to go through the same sort of dumb issues with EDFs. I really wish I had my own lathe, especially as this Lander motor has a strange shaft size. They've actually turned it down to fit the naff adapter from the 3mm standard shaft dia., and so only naff Lander adaptors will fit? Is that dumb or what? I won't be buying Lander units in future, that's for sure.

Sorry to moan, but I'm wondering if all manufacturers are the same, or is there any such thing as standard? I suppose I'm going to have the same sort of headaches with fans and mount hole spacings too...I should have stuck to props.
It is great idea to stick with known brands to avoid these headaches, I know what you feel like I often tried to combine different brands finding the same problem. Small hobby lathe is the greatest investment for modeller. Check the HK, EDF parts, they have number of adaptors, that might suit you. Joe.
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Old Jul 06, 2013, 12:39 AM
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Originally Posted by efflux RC View Post
The Wemotec 70mm EDFs have the most precision (tru-est running) shaft adaptors out there (for a composite EDF rotor). Motor shafts must either be 3.17mm or 4mm.
The bore for the motor shaft is slightly undersized, and requires heating with a gas stove or micro torch, before slipping onto the motor shaft. The set screws can then be installed (after cooling) with thread lock, and thier order of tightening adjusted to negate and slight runout you might feel when running the motor in a vise and feeling the shaft adaptor (rotor mounting area) with your finger. No flat is required on the motor. (there should NOT be a flat on the shaft)
Gary, I always put "tiny" flat on shafts without it, better safe than sorry, J.
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Old Jul 06, 2013, 12:53 AM
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I am with Gary, "flats" are not a good idea.
They just make it more difficult for the adaptor to run true.

We mount our fans at all power levels w/o flat and I canīt remember a rotor coming off, and we mount a couple thousand units a year.

Good adaptor, tight fit, proper mounting, thats the whole deal.

BTW, the Mini adaptor is available with 3.0 mm bore too.
But no idea if it is suitable for the Lander.

Oliver
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Old Jul 06, 2013, 02:03 AM
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Originally Posted by jofro View Post
Gary, I always put "tiny" flat on shafts without it, better safe than sorry, J.
My comment was that I do not put flats on the shaft when fitting to Wemo shaft adaptors due the interference fit.
Most motors in other fans, do get one .015" deep flat added to the shaft. (unless it's a "collet" type adaptor)
I offer it as a mod when shortening Mega motor shafts to fit E-flite 80mm EDFs.
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Old Jul 06, 2013, 02:36 AM
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Collets

Don't waist your money on a lathe unless your going to spend about $8000. The biggest problem isn't the actual lathe, but the chuck. Unless you use a "Zero Set" chuck, a standard lathe chuck is only going at the best .003". Thats nowhere good enough for a collet. I can get my Zero Set chuck down to .000025. That chuck was $2700, and it's made in Poland. Bison, one of the best around. You will also need a mill to cut slots into the arbor, oh, about $250 in tooling. I could never get a standard collet to work on any of my Dynamax conversions. Thats when I developed the collet built into the hub. Also the motor shaft has to be 8 mm, and at least 1.5" long.

My 2 cents worth

Larry E.
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Old Jul 06, 2013, 05:09 AM
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Originally Posted by WeMoTec View Post
..good adaptor, tight fit, proper mounting, thats the whole deal...BTW, the Mini adaptor is available with 3.0 mm bore too.

Oliver
Thanks Oliver, I'll remember the name Wemotec
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Old Jul 06, 2013, 05:21 AM
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Originally Posted by WeMoTec View Post
..BTW, the Mini adaptor is available with 3.0 mm bore too.But no idea if it is suitable for the Lander.

Oliver
Just ckecked and there is a mini adapter for 2.3mm shafts. What's not mentioned though are the outer diameters, and what make of fans fit these adapters?

BTW if one achieves an interference fit, does one really need grub screws?
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Old Jul 06, 2013, 11:58 AM
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What's not mentioned though are the outer diameters, and what make of fans fit these adapters?
Uhh......they are made for Wemotec fans. Again - some of the best fans around. When you buy the fan - you can choose which adapter you want.
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Old Jul 06, 2013, 12:16 PM
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Originally Posted by skyhawk View Post
Uhh......they are made for Wemotec fans. Again - some of the best fans around. When you buy the fan - you can choose which adapter you want.
Trouble is I'm in the UK and shipping cost is a massive Ģ16, and for the 3mm adaptor, I have to buy a minimum of 15, costing a total Ģ135! Other adaptors I can buy in single quantities, so why not the 3mm? Dunno, it's a crazy business...

I think I'll go back to normal motors and props.
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Old Jul 06, 2013, 05:54 PM
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A tiny grounded flat on the shaft never creates problem of adaptor to run true but is a "100%" insurance I won't come off, it's just a common sense and you don't need to be scientist to work that out.
Few years back I got 4 large HET 650 size motors to fit huge "C-130", with only cold pressed collets to hold the shaft with bell in place, you should have seen what happened during my first grounded test runs! After redesigning each motor they still run beaut, Joe.
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Old Jul 07, 2013, 05:21 PM
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Originally Posted by LJE4357 View Post
Don't waist your money on a lathe unless your going to spend about $8000. The biggest problem isn't the actual lathe, but the chuck. Unless you use a "Zero Set" chuck, a standard lathe chuck is only going at the best .003". Thats nowhere good enough for a collet. I can get my Zero Set chuck down to .000025. That chuck was $2700, and it's made in Poland. Bison, one of the best around. You will also need a mill to cut slots into the arbor, oh, about $250 in tooling. I could never get a standard collet to work on any of my Dynamax conversions. Thats when I developed the collet built into the hub. Also the motor shaft has to be 8 mm, and at least 1.5" long.

My 2 cents worth

Larry E.
Hi Larry, I couldn't live without my little hobby lathe. The best investment I ever made in this hobby I love so much. It paid itself off multiple times not mention stress and time I saved over the years. There is hardly a day I wouldn't use it, for instance, straitening the prop adaptor to "one thou". after striking small bird last week with 3blade warbird while taking off, Joe.
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