HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Sep 19, 2009, 08:33 PM
Hobby Flying
Joined Aug 2009
29 Posts
Alert
Do Not Use Hairdryer Engines Or Fans As Edfs

GREGg was right

I tested several types of Hairdryer fans all would not exceed more then 6amps
the baldes are not built for high speed applications
they were tested using a wind tunnel and if any one is concidering using any hairdryer fans be very carful (not recmmended)

the results are as below

Kambrook 3 phase rotor cracked at 4 amps 12 volts ppm at about 40,000
Engine blew at 5.6 amps 12 volt schamal inbeded in fome at 30 meters 5 inch deep

computer fan 3 phase rotor cracked at 5 amps with only 7.5volts ppm at about 31,000
engine blew at a wopping 6 volts 10amps schamal inbedded N/A

the smaller the moter the more reguler we expected the engines and blades to last

JS1400 EDF this baby can produce power run your own power station off this thing rotor trex blades craked at get this 246 amps 12volt ppm at about 56,000 schamel inbedded 15 to 30 inch,s a 22calibre inbeddeds at 10 to 15 inch
engine blew at amazing 320amps 12 volt ppm at the same as a pulse jet 64,456

this is information is subjected to the results found in testing in a wind tunnel and may vary to different environmatal factors as we didnt take in to account
TJDJ777 is offline Find More Posts by TJDJ777
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 19, 2009, 11:27 PM
Suspended Account
EDF Phantom - Kryptonic's Avatar
Joined Aug 2009
462 Posts
Deleted
EDF Phantom - Kryptonic is offline Find More Posts by EDF Phantom - Kryptonic
Last edited by EDF Phantom - Kryptonic; Sep 20, 2009 at 12:32 AM.
Reply With Quote
Old Sep 19, 2009, 11:41 PM
Deletedfor proving Nauga wrong
Joined Mar 2005
15,855 Posts
All you proved is the point of destruction for those particular fans.

At "bit lower" RPM they might be useful for relatively low performance EDFs...

USEFUL data would be what fan can reasonably be pushed to what rpm.

You can't stick the 3-blade adjustable pitch props sold by Hobby Lobby on an AXi 4130, feed it 12S and expect the prop to survive. its perfectly acceptable for use on a Dynam 22 series on 3S

I could easilly prove that a GWS40 mm EDF fan will "blow up" if I put enough power into it...
fhhuber506771 is offline Find More Posts by fhhuber506771
Reply With Quote
Old Sep 20, 2009, 12:32 AM
Suspended Account
EDF Phantom - Kryptonic's Avatar
Joined Aug 2009
462 Posts
Deleted.
EDF Phantom - Kryptonic is offline Find More Posts by EDF Phantom - Kryptonic
Reply With Quote
Old Sep 20, 2009, 12:40 AM
DELTAS RULE
corsair nut's Avatar
tehachapi, CA
Joined Jan 2006
22,458 Posts
umm...ya think?
corsair nut is online now Find More Posts by corsair nut
Reply With Quote
Old Sep 20, 2009, 01:21 AM
Registered Plan-a-holic
Hepdog's Avatar
Stonewall, MB, Can
Joined Jul 2004
2,875 Posts
What kind of fan are you testing that only draws 4 amps at 40000RPM? 5 amps on 2S at 31,000 rpm???

There is something seriously wrong with those numbers. The fan diameter must be around 1inch or less to not generate any amp draw for that RPM and if so, well no

I built a fan using CPU cooling blades 3 years ago. It was about 70mm in diameter and could easily absorb 21 amps on 3S while spinning 21,000rpm (turbine tach). Put out a healthy 16oz of thrust but not much efflux. Was good for what I wanted though - 3D EDF.
Hepdog is offline Find More Posts by Hepdog
Last edited by Hepdog; Sep 20, 2009 at 01:30 AM.
Reply With Quote
Old Sep 20, 2009, 02:03 AM
Hobby Flying
Joined Aug 2009
29 Posts
Quote:
Originally Posted by fhhuber506771
All you proved is the point of destruction for those particular fans.

At "bit lower" RPM they might be useful for relatively low performance EDFs...

USEFUL data would be what fan can reasonably be pushed to what rpm.

You can't stick the 3-blade adjustable pitch props sold by Hobby Lobby on an AXi 4130, feed it 12S and expect the prop to survive. its perfectly acceptable for use on a Dynam 22 series on 3S

I could easilly prove that a GWS40 mm EDF fan will "blow up" if I put enough power into it...

Yes you are right
we found that if you used the fans from a more expensive hairdryer they will be able to hold the torque on a proper edf but the engines are just so slow we measured the air pressure with ppm (parts per million) it dose come close to rpm readings but not close enought that might have bien why we couldn't get accurate reading there were a lot of if and buts during our testing
TJDJ777 is offline Find More Posts by TJDJ777
Reply With Quote
Old Sep 20, 2009, 02:12 AM
Deletedfor proving Nauga wrong
Joined Mar 2005
15,855 Posts
Quote:
Originally Posted by TJDJ777
Yes you are right
we found that if you used the fans from a more expensive hairdryer they will be able to hold the torque on a proper edf but the engines are just so slow we measured the air pressure with ppm (parts per million) it dose come close to rpm readings but not close enought that might have bien why we couldn't get accurate reading there were a lot of if and buts during our testing
In other words...

totally useless data.

Now you come out with even the RPM were estimates, not measured.
fhhuber506771 is offline Find More Posts by fhhuber506771
Reply With Quote
Old Sep 20, 2009, 02:15 AM
Deletedfor proving Nauga wrong
Joined Mar 2005
15,855 Posts
Quote:
Originally Posted by Hepdog
What kind of fan are you testing that only draws 4 amps at 40000RPM? 5 amps on 2S at 31,000 rpm???

There is something seriously wrong with those numbers. The fan diameter must be around 1inch or less to not generate any amp draw for that RPM and if so, well no

I built a fan using CPU cooling blades 3 years ago. It was about 70mm in diameter and could easily absorb 21 amps on 3S while spinning 21,000rpm (turbine tach). Put out a healthy 16oz of thrust but not much efflux. Was good for what I wanted though - 3D EDF.
I need to learn your foam forming techniques...
fhhuber506771 is offline Find More Posts by fhhuber506771
Reply With Quote
Old Sep 20, 2009, 02:26 AM
Registered User
Joined Jun 2002
860 Posts
No huber, not useless data. Interesting data.

Just as important to know what doesn't work, as it is to know what does work.
Ron Pogue is offline Find More Posts by Ron Pogue
Reply With Quote
Old Sep 20, 2009, 02:38 AM
Hobby Flying
Joined Aug 2009
29 Posts
iam having trouble downloading the photo's of the three hairdryer fans and the computer fan we tested

the one that pulled 40,000 ppm is the kambrook hairdryer

the second one is a cheep brand hairdryer it pulled only about 25,000ppm

the third one is an expensive commercial hairdryer used in hairdresses salloon the engine didn't blow up but it did burn out pulling up to about 45,000ppm we tested in an air tunnel on a 25 degrees heat day may played a bit in confusing us with the results

the computer fan we used the blades on three different motors before the started to strech my accumpany decided to rev it up a bit and put anomonous amounts of power through it some thing like 6 amps to 150 volts it didnt blow so he turned it up to 240 volts still didn't blow it was smoking though as we only have 240 over here in our powerlines he decided to turn up the amps from 6 amp to 6.20 ohms then up to 6.3, 6.4, 6.5 when we got to 6.592 the engine blew up
TJDJ777 is offline Find More Posts by TJDJ777
Reply With Quote
Old Sep 20, 2009, 02:39 AM
Deletedfor proving Nauga wrong
Joined Mar 2005
15,855 Posts
Quote:
Originally Posted by Ron Pogue
No huber, not useless data. Interesting data.

Just as important to know what doesn't work, as it is to know what does work.
It would be interresting if it had reliable numbers....

What he's got is a stated claim of data and then he refutes its validity by explaining how they came up with the numbers... essentially total wild guesswork.

If you take a dozen of one particular fan and run each up to destruction rpm, increasing the rpm gradually (measured with a tach... not estimated) and all 12 fail within 10% of the same RPM... then you have data to indicate you shouldn't run that fan above the failure rpm of the lowest speed of failure. (and a "good engineering practice" safety margin would reccommend 75% of the RPM that caused any failure)

What they came up with from thier "tests" is of no value at all...
fhhuber506771 is offline Find More Posts by fhhuber506771
Reply With Quote
Old Sep 20, 2009, 02:51 AM
Hobby Flying
Joined Aug 2009
29 Posts
we only tested two edfs the js1400 the brand new one that just came out and a OS600 we used the same blades on both of them the tech it came with the js1400
and a spare we used on the OS600 besides just blowing these things up just for the fun of it what would you recmommend the OS600 brushless fan be good for i have a spare and don't know what to do with it
TJDJ777 is offline Find More Posts by TJDJ777
Reply With Quote
Old Sep 20, 2009, 03:04 AM
Hobby Flying
Joined Aug 2009
29 Posts
yes i know
yes we did test theses different types of hairdryers once over
my opinion is the tests could have bien a bit presumpious
working with the pyro's iam forced to deal with it would have bien a better result if we used the same fan through out the whole test or tested each type of fan three times
they just wanted to blow something up

if any one can come up with a smiller test more accuatly please let me know i would greatfully be interested in your findings
TJDJ777 is offline Find More Posts by TJDJ777
Reply With Quote
Old Sep 20, 2009, 03:44 AM
Angry Bird ...
yarrumevets's Avatar
Sydney, Australia
Joined Aug 2007
861 Posts
I'm sorry, but none of this looks to be useful at all TJDJ777 - it's great to see that you've been out to do some testing and your intentions are admirable, but this is completely unscientific and Huber is right, it's useless. In particular ...

1. It's not possible to measure air pressure in parts per million, a totally incredible suggestion.
2. It seems you've been intent on testing to destruction, which is alright, but you need to be able to repeat your tests on the same fan/motor/... combinations and get statistically consistent results.
3. What, by the way, is "schamal inbeded in fome"?
yarrumevets is offline Find More Posts by yarrumevets
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Plz do NOT use hydrogen for your hobby Deserteagle Blimps 1 Apr 18, 2008 09:35 PM
Discussion Should We Do Business With Companies That Do Not Have the Same Copywrite Laws as US? Kenny Sharp Vendor Talk 26 Dec 26, 2007 11:06 PM
Discussion Rotortech 350mm Blades - DO NOT USE!!! Heli Addict Mini Helis 7 Aug 19, 2007 12:30 AM
Discussion New Computer question-Do I use onboard Video or Migrate my old Vid card? mrebman Life, The Universe, and Politics 42 Dec 15, 2006 12:01 PM
Yak 55 Great Planes:do Not Use Kicker 9LIVES1968 3D Flying 8 May 04, 2005 03:19 PM