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Old Nov 10, 2011, 11:01 AM
You win again gravity!
SMorrisRC's Avatar
UK
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Alloy 90mm EDF from EPF Hobby

Hi everyone,

There is a new all-alloy 90mm EDF on it's way from EPF Hobby!

www.epf.com.tw


No real specs yet, but if it's anything like the 64mm one it will be fantastic! Looks like the same 3-bearing design, which I really like - much better than a conventional layout in my opinion, and price should be around $250 or so, complete, all balanced and ready to go!

Can't wait to get my hands on one of these.........................
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Last edited by SMorrisRC; Dec 30, 2011 at 04:04 PM. Reason: Requested by effluxrc
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Old Nov 10, 2011, 12:07 PM
High Dynamic Thrust
stoneenforcer's Avatar
United States, FL, Mt Dora
Joined Feb 2007
2,304 Posts
IMHO aluminum fans are best as paper weights and in no way produce any performance advantage over existing carbon or even resin shrouds. they dont event stay the same DIA in various temp ranges, are heavier, cant stay round if bumped or crashed, . shame they cant put the mfg efforts towards more innovative products. if the rotor is aluminum, then the varying space between the rotor and shroud will always fluctuate, pending on flying climate and heat disapation. this inconsistancy inconjunction with being heavier, pretty much out ways the design changes to decrease very minor flow frictions. just dont see paying that much causes it shiny and perhaps a cool factor to the eye. i assume their going with the integrated outrunner amp sucking method? shame... cause the integrated inrunner is much more efficient. but we all know.... outrunners are cheaper. lol

if im wrong, id like to see the numbers to prove the efficiency, calculated with the weight factor, which mfg's rarely do.
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Old Nov 10, 2011, 12:31 PM
You win again gravity!
SMorrisRC's Avatar
UK
Joined Jan 2010
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You're entitled to your own opinion, but based on my experience of the 64mm size I prefer them. Yes, they are shiny, and would make an excellent paper weight, and are just nice to look at and admire the engineering............but it is functional too (there's a reason real planes don't fly around with plastic fans and propellers you know............)

Firstly, they just sound cool.........not like a sex toy like a lot of plastic ones do.
The metal also gives excellent heat dissipation properties allowing everything to run cooler.
The blades are more rigid so can carry more load = more thrust (just see the Mach alloy fans from efflux rc for proof of that!)
And, in the case of these ones, the fan being supported at either end is a much improved design in my opinion. Even the best balanced fan in the world will suffer from flex issues in flight due to gyroscopic forces. Having it supported front and back, as in this case, eliminates most of the problem.
You're right though, they are often heavier, and I don't know how heavy this one will be, but if it's like the 64mm version, the weight penalty won't be too bad I don't think. Certainly shouldn't be as heavy as the RC Lander units.
Finally, if you bump or crash a plastic / resin EDF, sure the shroud may return to shape, but you'll have grenaded your fan anyway............which is the bulk of the cost. And if you've landed hard enough to bend an alloy shroud then you should take some flying lessons!

If you are happy with average performance then plastic / resin is fine. But, if you want more power, then you need a more rigid material...............so carbon or metal. I live in the UK, where it's always wet and cold, so I don't like the idea of carbon. Too much risk of delamination. So, metal it is..............and it's cheaper, of course.
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Old Nov 10, 2011, 12:35 PM
You win again gravity!
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And just to be clear, the 12 blades are also metal..............not just the shroud.
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Old Nov 10, 2011, 12:36 PM
High Dynamic Thrust
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United States, FL, Mt Dora
Joined Feb 2007
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a metal rotor on edf is an even bigger killer of performance. sure it works and looks cool , but when you get down to the numbers and facts when spending that kind of money for a fan.... you will find there are many more options to choose from that simply provide greater performance at same or much less money.

i fly carbon fans
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Old Nov 10, 2011, 12:42 PM
You win again gravity!
SMorrisRC's Avatar
UK
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Do you have any idea how small the effects of thermal expansion on a metal rotor are versus the 'stretch' you'd get from a traditional rotor when it spins up?? Plus, if the rotor and shroud are the same material, won't they expand the same amount with temp???

Plus, all materials change size with temperature, not just metal!
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Old Nov 10, 2011, 12:43 PM
You win again gravity!
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I also think $250 is pretty good for a 90mm setup..............at least here in the UK.
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Old Nov 10, 2011, 12:51 PM
You win again gravity!
SMorrisRC's Avatar
UK
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Quote:
Originally Posted by stoneenforcer View Post
a metal rotor on edf is an even bigger killer of performance. sure it works and looks cool , but when you get down to the numbers and facts when spending that kind of money for a fan.... you will find there are many more options to choose from that simply provide greater performance at same or much less money.

i fly carbon fans
How much is a decent 90mm carbon fan?.......just out of interest?
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Old Nov 10, 2011, 12:53 PM
EDF all the way!
bruff's Avatar
Gilbert, Az
Joined Jun 1999
7,983 Posts
I gave up on carbon rotors. To easy to FOD out.
Bob
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Old Nov 10, 2011, 12:59 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
20,932 Posts
do ou have a pic of the rotor? i have the Efflux /mach 70mm fan i really like the sound and smoothness ,the number of blades really loads the motor ,so finding the right motor really helps. i do like the 3 bering for support . at the power levels we are getting too alloy rotors are a step in the right direction. keep us posted.
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Old Nov 10, 2011, 01:11 PM
Registered User
maghull , merseyside
Joined Aug 2010
254 Posts
Quote:
Originally Posted by SMorrisRC View Post
You're entitled to your own opinion, but based on my experience of the 64mm size I prefer them. Yes, they are shiny, and would make an excellent paper weight, and are just nice to look at and admire the engineering............but it is functional too (there's a reason real planes don't fly around with plastic fans and propellers you know............)

Firstly, they just sound cool.........not like a sex toy like a lot of plastic ones do.
The metal also gives excellent heat dissipation properties allowing everything to run cooler.
The blades are more rigid so can carry more load = more thrust (just see the Mach alloy fans from efflux rc for proof of that!)
And, in the case of these ones, the fan being supported at either end is a much improved design in my opinion. Even the best balanced fan in the world will suffer from flex issues in flight due to gyroscopic forces. Having it supported front and back, as in this case, eliminates most of the problem.
You're right though, they are often heavier, and I don't know how heavy this one will be, but if it's like the 64mm version, the weight penalty won't be too bad I don't think. Certainly shouldn't be as heavy as the RC Lander units.
Finally, if you bump or crash a plastic / resin EDF, sure the shroud may return to shape, but you'll have grenaded your fan anyway............which is the bulk of the cost. And if you've landed hard enough to bend an alloy shroud then you should take some flying lessons!

If you are happy with average performance then plastic / resin is fine. But, if you want more power, then you need a more rigid material...............so carbon or metal. I live in the UK, where it's always wet and cold, so I don't like the idea of carbon. Too much risk of delamination. So, metal it is..............and it's cheaper, of course.
If they are as good as the Mercury units (ive got four) then they will be my first choice for a 90mm EDF. I dont really see relative weight between plastic and metal being a big factor when you get up to the larger fan sizes in big airframes. Not sure about alloy fans being a killer in performance either, but lets wait for the figures before asking EPF Hobby to make something more innovative.

Hmmmmmmmm, I wonder if I can power my blow up doll with one.
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Old Nov 10, 2011, 01:11 PM
You win again gravity!
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I don't have a pic of the rotor yet.............I hope to be able to get one soon though.
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Old Nov 10, 2011, 01:17 PM
High Dynamic Thrust
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United States, FL, Mt Dora
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im looking forward to seeing numbers. heck.... if there where they "should" be for a premium priced fan, then I'll reconsider the purchase.
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Old Nov 10, 2011, 01:18 PM
You win again gravity!
SMorrisRC's Avatar
UK
Joined Jan 2010
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Quote:
Originally Posted by BRIARCROFT View Post
If they are as good as the Mercury units (ive got four) then they will be my first choice for a 90mm EDF. I dont really see relative weight between plastic and metal being a big factor when you get up to the larger fan sizes in big airframes. Not sure about alloy fans being a killer in performance either, but lets wait for the figures before asking EPF Hobby to make something more innovative.

Hmmmmmmmm, I wonder if I can power my blow up doll with one.
You might want to wait for the 120mm.
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Old Nov 10, 2011, 02:22 PM
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maghull , merseyside
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Originally Posted by SMorrisRC View Post
You might want to wait for the 120mm.
Been waiting all my life for 120mm! Lol
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