jim beam wrote:
> Hachiroku $B%O%A%m%/ wrote:
>
>> On Wed, 02 May 2007 22:34:13 -0700, jim beam wrote:
>>
>>> Hachiroku $B%O%A%m%/ wrote:
>>>
>>>> On Wed, 02 May 2007 21:29:25 -0700, jim beam wrote:
>>>>
>>>>>> The old belt driven fans changed to plastic blades because they could
>>>>>> flatten out at higher speeds
>>>>>
>>>>> by "flatten out" do you mean a variable pitch fan blade? that's
>>>>> somewhat exotic and rather expensive. what used them?
>>>>
>>>>
>>>> My Supra has one. Also a Celica I had ('85) and an '85 Corolla.
>>>>
>>>> Most of the fans post 75 or so are plastic, one reason being weight and
>>>> the other being the flexability of plastic. I can't remember the last
>>>> time I saw a metal fan!
>>>>
>>>>
>>> just because it's plastic does not mean it's flexible enough to "flatten
>>> out" as if it's variable pitch. what mechanical properties do /you/
>>> think
>>> "flexibility" gives the fan?
>>
>>
>>
>> Who cares?
>>
> you should if you want the fan to move the freakin' air that you think
> is cooling your engine!!! if the blades can adopt a position of least
> resistance, they will. that means throughput will be minimal - totally
> defeats their supposed purpose.


I would be inclined to think that these fans could actually inhibit
cooling during high speed driving as the "flattened" fan blades would
act muck like a feathered prop in the wrong position which then enters a
windmilling mode.

I never had any confidence in these "devices."

JT

 

jim beam wrote:
> Hachiroku $B%O%A%m%/ wrote:
>
>> On Wed, 02 May 2007 22:34:13 -0700, jim beam wrote:
>>
>>> Hachiroku $B%O%A%m%/ wrote:
>>>
>>>> On Wed, 02 May 2007 21:29:25 -0700, jim beam wrote:
>>>>
>>>>>> The old belt driven fans changed to plastic blades because they could
>>>>>> flatten out at higher speeds
>>>>>
>>>>> by "flatten out" do you mean a variable pitch fan blade? that's
>>>>> somewhat exotic and rather expensive. what used them?
>>>>
>>>>
>>>> My Supra has one. Also a Celica I had ('85) and an '85 Corolla.
>>>>
>>>> Most of the fans post 75 or so are plastic, one reason being weight and
>>>> the other being the flexability of plastic. I can't remember the last
>>>> time I saw a metal fan!
>>>>
>>>>
>>> just because it's plastic does not mean it's flexible enough to "flatten
>>> out" as if it's variable pitch. what mechanical properties do /you/
>>> think
>>> "flexibility" gives the fan?
>>
>>
>>
>> Who cares?
>>
> you should if you want the fan to move the freakin' air that you think
> is cooling your engine!!! if the blades can adopt a position of least
> resistance, they will. that means throughput will be minimal - totally
> defeats their supposed purpose.


I would be inclined to think that these fans could actually inhibit
cooling during high speed driving as the "flattened" fan blades would
act muck like a feathered prop in the wrong position which then enters a
windmilling mode.

I never had any confidence in these "devices."

JT

 

Grumpy AuContraire wrote:
>
>
> jim beam wrote:
>> Hachiroku $B%O%A%m%/ wrote:
>>
>>> On Wed, 02 May 2007 22:34:13 -0700, jim beam wrote:
>>>
>>>> Hachiroku $B%O%A%m%/ wrote:
>>>>
>>>>> On Wed, 02 May 2007 21:29:25 -0700, jim beam wrote:
>>>>>
>>>>>>> The old belt driven fans changed to plastic blades because they
>>>>>>> could
>>>>>>> flatten out at higher speeds
>>>>>>
>>>>>> by "flatten out" do you mean a variable pitch fan blade? that's
>>>>>> somewhat exotic and rather expensive. what used them?
>>>>>
>>>>>
>>>>> My Supra has one. Also a Celica I had ('85) and an '85 Corolla.
>>>>>
>>>>> Most of the fans post 75 or so are plastic, one reason being weight
>>>>> and
>>>>> the other being the flexability of plastic. I can't remember the last
>>>>> time I saw a metal fan!
>>>>>
>>>>>
>>>> just because it's plastic does not mean it's flexible enough to
>>>> "flatten
>>>> out" as if it's variable pitch. what mechanical properties do /you/
>>>> think
>>>> "flexibility" gives the fan?
>>>
>>>
>>>
>>> Who cares?
>>>
>> you should if you want the fan to move the freakin' air that you think
>> is cooling your engine!!! if the blades can adopt a position of least
>> resistance, they will. that means throughput will be minimal -
>> totally defeats their supposed purpose.
>
>
> I would be inclined to think that these fans could actually inhibit
> cooling during high speed driving as the "flattened" fan blades would
> act muck like a feathered prop in the wrong position which then enters a
> windmilling mode.

agreed!

>
> I never had any confidence in these "devices."
>
> JT
>

 

Grumpy AuContraire wrote:
>
>
> jim beam wrote:
>> Hachiroku $B%O%A%m%/ wrote:
>>
>>> On Wed, 02 May 2007 22:34:13 -0700, jim beam wrote:
>>>
>>>> Hachiroku $B%O%A%m%/ wrote:
>>>>
>>>>> On Wed, 02 May 2007 21:29:25 -0700, jim beam wrote:
>>>>>
>>>>>>> The old belt driven fans changed to plastic blades because they
>>>>>>> could
>>>>>>> flatten out at higher speeds
>>>>>>
>>>>>> by "flatten out" do you mean a variable pitch fan blade? that's
>>>>>> somewhat exotic and rather expensive. what used them?
>>>>>
>>>>>
>>>>> My Supra has one. Also a Celica I had ('85) and an '85 Corolla.
>>>>>
>>>>> Most of the fans post 75 or so are plastic, one reason being weight
>>>>> and
>>>>> the other being the flexability of plastic. I can't remember the last
>>>>> time I saw a metal fan!
>>>>>
>>>>>
>>>> just because it's plastic does not mean it's flexible enough to
>>>> "flatten
>>>> out" as if it's variable pitch. what mechanical properties do /you/
>>>> think
>>>> "flexibility" gives the fan?
>>>
>>>
>>>
>>> Who cares?
>>>
>> you should if you want the fan to move the freakin' air that you think
>> is cooling your engine!!! if the blades can adopt a position of least
>> resistance, they will. that means throughput will be minimal -
>> totally defeats their supposed purpose.
>
>
> I would be inclined to think that these fans could actually inhibit
> cooling during high speed driving as the "flattened" fan blades would
> act muck like a feathered prop in the wrong position which then enters a
> windmilling mode.

agreed!

>
> I never had any confidence in these "devices."
>
> JT
>

 

"Grumpy AuContraire" <Grumpy@ExtraGrumpyville.com> wrote in message
news:tnn%h.110802$VU4.33178@bgtnsc05-news.ops.worldnet.att.net...
>
>
> I would be inclined to think that these fans could actually inhibit
> cooling during high speed driving as the "flattened" fan blades would act
> muck like a feathered prop in the wrong position which then enters a
> windmilling mode.
>
> I never had any confidence in these "devices."
>
> JT
>
>
I don't think they can inhibit air flow that way because the air pressure
against the blade is what flexes them "flatter." At least in theory, they
should still be pushing air.

To each their own.

Mike

 

"Grumpy AuContraire" <Grumpy@ExtraGrumpyville.com> wrote in message
news:tnn%h.110802$VU4.33178@bgtnsc05-news.ops.worldnet.att.net...
>
>
> I would be inclined to think that these fans could actually inhibit
> cooling during high speed driving as the "flattened" fan blades would act
> muck like a feathered prop in the wrong position which then enters a
> windmilling mode.
>
> I never had any confidence in these "devices."
>
> JT
>
>
I don't think they can inhibit air flow that way because the air pressure
against the blade is what flexes them "flatter." At least in theory, they
should still be pushing air.

To each their own.

Mike

 

"jim beam" <spamvortex@bad.example.net> wrote in message
news:kMKdnXqZb-ryc6DbnZ2dnUVZ_jKdnZ2d@speakeasy.net...
> Michael Pardee wrote:
>> http://www.flex-a-lite.com/auto/html/7-blade-flex.html
> did you know that the outer extremity of a fan blade moves faster than the
> bit nearest the hub? apparently these guys don't since it's the same
> pitch for the whole blade!!! what a total p.o.s.
>
You're right about the change in air speed and that the ideal pitch should
vary along the blades like the pitch on an airplane propellor or a ship
"screw." This isn't rocket science, though, it's just a radiator fan they
are trying to improve a bit. Regular fans work and these fans work. Take
your choice (I think you already did!)

Mike

 

"jim beam" <spamvortex@bad.example.net> wrote in message
news:kMKdnXqZb-ryc6DbnZ2dnUVZ_jKdnZ2d@speakeasy.net...
> Michael Pardee wrote:
>> http://www.flex-a-lite.com/auto/html/7-blade-flex.html
> did you know that the outer extremity of a fan blade moves faster than the
> bit nearest the hub? apparently these guys don't since it's the same
> pitch for the whole blade!!! what a total p.o.s.
>
You're right about the change in air speed and that the ideal pitch should
vary along the blades like the pitch on an airplane propellor or a ship
"screw." This isn't rocket science, though, it's just a radiator fan they
are trying to improve a bit. Regular fans work and these fans work. Take
your choice (I think you already did!)

Mike

 

Michael Pardee wrote:
> "Grumpy AuContraire" <Grumpy@ExtraGrumpyville.com> wrote in message
> news:tnn%h.110802$VU4.33178@bgtnsc05-news.ops.worldnet.att.net...
>
>>
>>I would be inclined to think that these fans could actually inhibit
>>cooling during high speed driving as the "flattened" fan blades would act
>>muck like a feathered prop in the wrong position which then enters a
>>windmilling mode.
>>
>>I never had any confidence in these "devices."
>>
>>JT
>>
>>
>
> I don't think they can inhibit air flow that way because the air pressure
> against the blade is what flexes them "flatter." At least in theory, they
> should still be pushing air.
>
> To each their own.
>
> Mike
>


Nope, the higher the RPM, the greater deflection of air, almost like
having a circle of plywood right in back of the radiator.... So much
so, it could become a negative factor at higher rpms. "Silence" has a
price...

JT

 

Michael Pardee wrote:
> "Grumpy AuContraire" <Grumpy@ExtraGrumpyville.com> wrote in message
> news:tnn%h.110802$VU4.33178@bgtnsc05-news.ops.worldnet.att.net...
>
>>
>>I would be inclined to think that these fans could actually inhibit
>>cooling during high speed driving as the "flattened" fan blades would act
>>muck like a feathered prop in the wrong position which then enters a
>>windmilling mode.
>>
>>I never had any confidence in these "devices."
>>
>>JT
>>
>>
>
> I don't think they can inhibit air flow that way because the air pressure
> against the blade is what flexes them "flatter." At least in theory, they
> should still be pushing air.
>
> To each their own.
>
> Mike
>


Nope, the higher the RPM, the greater deflection of air, almost like
having a circle of plywood right in back of the radiator.... So much
so, it could become a negative factor at higher rpms. "Silence" has a
price...

JT