Why are these fitted instead of just a stationary vent like you see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was already moving. Surely that's like fitting a generator to your bicycle to power a motor to make you go faster?

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was already moving. Surely that's like fitting a generator to your bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was already moving. Surely that's like fitting a generator to your bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why? How can you take power from the wind to then give it back to make it faster? Isn't that breaking the laws of physics?

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why?

Because they are a fan, powered by the wind.

How can you take power from the wind to then give it back to make it
faster?

That isnt how they work. Think of it as a fan,
which even you should realise is better than
no fan, and powering that fan with the wind.

Isn't that breaking the laws of physics?

Nope.

On Thu, 25 Oct 2018 16:31:38 +0100, Rod Speed wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why?

Because they are a fan, powered by the wind.

A turbine converts wind to electricity. A fan converts electricity to wind. What we have here is something that converts it and then straight back, pointless. You might aswell put a wind turbine and an electric fan connected together on there, it would be no more stupid.

How can you take power from the wind to then give it back to make it
faster?

That isnt how they work. Think of it as a fan,
which even you should realise is better than
no fan, and powering that fan with the wind.

Isn't that breaking the laws of physics?

Nope.

But you're powering that "fan" by the motion of the air, then using the power to create motion of air, which was already there anyway. It would be like having a solar powered lightbulb.

On Thu, 25 Oct 2018 16:58:21 +0100, "Gym Sulkinson Fork"
wrote:

On Thu, 25 Oct 2018 16:31:38 +0100, Rod Speed wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why?

Because they are a fan, powered by the wind.

A turbine converts wind to electricity. A fan converts electricity to wind. What we have here is something that converts it and then straight back, pointless. You might aswell put a wind turbine and an electric fan connected together on there, it would be no more stupid.

How can you take power from the wind to then give it back to make it
faster?

That isnt how they work. Think of it as a fan,
which even you should realise is better than
no fan, and powering that fan with the wind.

Isn't that breaking the laws of physics?

Nope.

But you're powering that "fan" by the motion of the air, then using the power to create motion of air, which was already there anyway. It would be like having a solar powered lightbulb.

I suspect you are just trolling, but I'll chime in anyway. These
devices use the motion of the air traveling past your building (ie,
horizontal motion) into suction that draws hot air up and out of your
building. They work better than just using the upward motion of the
air created by hot air being lighter than cooler air.

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:31:38 +0100, Rod Speed
wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why?

Because they are a fan, powered by the wind.

A turbine converts wind to electricity. A fan converts electricity to
wind.

Yes, but that still does help move the hot air out of the roof space.

What we have here is something that converts it and then straight back,
pointless.

What you actually have is a more efficient way of using the
wind to power the fan, without the inefficiency involved in
the use of electricity between the generator and the fan.

You might aswell put a wind turbine and an electric fan connected together
on there,

Yes, that would certainly work too.

it would be no more stupid.

Much more stupid given how inefficient the wind powered
generator is. Much better to have the wind turn the vent and
have the fan part of that thing that turns, directly coupled.

How can you take power from the wind to then give it back to make it
faster?

That isnt how they work. Think of it as a fan,
which even you should realise is better than
no fan, and powering that fan with the wind.

Isn't that breaking the laws of physics?

Nope.

But you're powering that "fan" by the motion of the air, then using the
power to create motion of air,

Yes.

which was already there anyway.

Nope, not with the hot air in the roofspace.

It would be like having a solar powered lightbulb.

Nope, those are much less efficient and we do have
solar powered light bulbs, with batterys in them
so you get the light at night after the sun is gone.

In alt.home.repair, on Thu, 25 Oct 2018 16:58:21 +0100, "Gym Sulkinson
Fork" wrote:

On Thu, 25 Oct 2018 16:31:38 +0100, Rod Speed wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why?

Because they are a fan, powered by the wind.

A turbine converts wind to electricity. A fan converts electricity to wind.

Not this one. No electricity. It converts horizontal wind to
vertical wind.

What we have here is something that converts it and then straight back, pointless. You might aswell put a wind turbine and an electric fan connected together on there, it would be no more stupid.

If you would stand under one, you wouldn't say this.



How can you take power from the wind to then give it back to make it
faster?

That isnt how they work. Think of it as a fan,
which even you should realise is better than
no fan, and powering that fan with the wind.

Isn't that breaking the laws of physics?

Nope.

But you're powering that "fan" by the motion of the air, then using the power to create motion of air, which was already there anyway. It would be like having a solar powered lightbulb.

That's a good idea! And they already have them. Lights that store
electricity in the day so that they run without power cords at night

On Fri, 26 Oct 2018 02:31:38 +1100, cantankerous trolling senile geezer Rot
Speed blabbered, again:

That isnt how they work. Think of it as a fan,

We think of you and him as the two village idiots on these groups!

--
Archibald Tarquin Blenkinsopp addressing Rot Speed:
"You really are a clueless pillock."
MID:

On 25/10/2018 16:07, Gym Sulkinson Fork wrote:
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see
on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving.* Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why?* How can you take
power from the wind to then give it back to make it faster?* Isn't that
breaking the laws of physics?

They are a Savonius rotor, which uses the wind to rotate a shaft. There
is a fan attached to the shaft, which, unlike a simple hole, actively
extracts air from the vehicle. They are also widely used on boats, to
keep them ventilated while sitting at their moorings.

--
--

Colin Bignell

On Thu, 25 Oct 2018 17:11:41 +0100, Nightjar wrote:

On 25/10/2018 16:07, Gym Sulkinson Fork wrote:
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see
on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why? How can you take
power from the wind to then give it back to make it faster? Isn't that
breaking the laws of physics?

They are a Savonius rotor, which uses the wind to rotate a shaft. There
is a fan attached to the shaft, which, unlike a simple hole, actively
extracts air from the vehicle. They are also widely used on boats, to
keep them ventilated while sitting at their moorings.

I'd just open the window (with a rain guard of course).

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 17:11:41 +0100, Nightjar wrote:

On 25/10/2018 16:07, Gym Sulkinson Fork wrote:
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see
on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why? How can you take
power from the wind to then give it back to make it faster? Isn't that
breaking the laws of physics?

They are a Savonius rotor, which uses the wind to rotate a shaft. There
is a fan attached to the shaft, which, unlike a simple hole, actively
extracts air from the vehicle. They are also widely used on boats, to
keep them ventilated while sitting at their moorings.

I'd just open the window (with a rain guard of course).

Doesn't work when the boat is unattended and those things are
completely automatic, you don't need to know when it might rain
and when to shut the window.

Gym Sulkinson Fork wrote:
On Thu, 25 Oct 2018 17:11:41 +0100, Nightjar
wrote:
On 25/10/2018 16:07, Gym Sulkinson Fork wrote:
On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you
see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the
air was already moving. Surely that's like fitting a generator
to your bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why? How can you
take power from the wind to then give it back to make it faster? Isn't
that breaking the laws of physics?

They are a Savonius rotor, which uses the wind to rotate a shaft.
There is a fan attached to the shaft, which, unlike a simple hole,
actively extracts air from the vehicle. They are also widely used on
boats, to keep them ventilated while sitting at their moorings.

I'd just open the window (with a rain guard of course).

Another Hucker troll.

On Thu, 25 Oct 2018 17:11:41 +0100, Nightjar, another brain damaged,
troll-feeding senile idiot, blathered:


They are a Savonius rotor, which uses the wind to rotate a shaft. There
is a fan attached to the shaft, which, unlike a simple hole, actively
extracts air from the vehicle. They are also widely used on boats, to
keep them ventilated while sitting at their moorings.

And yet another senile idiot fell for the retarded Scottish attention
whore's latest idiotic bait, hook, line and sinker! LOL

On 25/10/2018 17:11, Nightjar wrote:
They are a Savonius rotor, which uses the wind to rotate a shaft. There
is a fan attached to the shaft, which, unlike a simple hole, actively
extracts air from the vehicle. They are also widely used on boats, to
keep them ventilated while sitting at their moorings.

And they have the advantage that they work with the wind in any
direction. Even when you are parked (or moored!)

Andy

On Fri, 26 Oct 2018 21:43:51 +0100, Vir Campestris wrote:

On 25/10/2018 17:11, Nightjar wrote:
They are a Savonius rotor, which uses the wind to rotate a shaft. There
is a fan attached to the shaft, which, unlike a simple hole, actively
extracts air from the vehicle. They are also widely used on boats, to
keep them ventilated while sitting at their moorings.

And they have the advantage that they work with the wind in any
direction. Even when you are parked (or moored!)

Moored?!
https://youtu.be/OgpfYBMqURw?t=70

On Thu, 25 Oct 2018 16:07:30 +0100, "Gym Sulkinson Fork"
wrote:

On Thu, 25 Oct 2018 16:03:22 +0100, wrote:

On Thu, 25 Oct 2018 15:47:48 +0100, "Gym Sulkinson Fork"
wrote:

Why are these fitted instead of just a stationary vent like you see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was already moving. Surely that's like fitting a generator to your bicycle to power a motor to make you go faster?

They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

Yes I know they claim to be more efficient, but why? How can you take power from the wind to then give it back to make it faster? Isn't that breaking the laws of physics?

Any ambient wind will spin the turbine and pump air out. On a
perfectly calm day, I doubt there is much gain at all.

On Thu, 25 Oct 2018 13:07:55 -0400, , the mentally
deficient, troll-feeding senile idiot, blathered:



Any ambient wind will spin the turbine and pump air out. On a
perfectly calm day, I doubt there is much gain at all.

You turned out to be one of the gay Scottish ******'s most devoted
cocksuckers! LOL

On Thu, 25 Oct 2018 11:03:22 -0400, , another obviously
mentally handicapped troll-feeding senile idiot, blathered:


They are just more efficient than a simple hole in the roof with
sufficient cover to keep the rain out. If there was a better mouse
trap, somebody would have made one in the last 200 years.

....and troll-feeding idiot no.1 arrived to swallow the Scottish attention
whore's latest idiotic bait, hook, line and sinker again! Just HOW senile
are you all on ahr? BG

On 25/10/2018 15:47, Gym Sulkinson Fork wrote:
Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving.* Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

As it spins I think it disperses driver/passenger farts far more
efficiently.

On Thu, 25 Oct 2018 16:06:10 +0100, Andy Bennet wrote:

On 25/10/2018 15:47, Gym Sulkinson Fork wrote:
Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

As it spins I think it disperses driver/passenger farts far more
efficiently.

Is there a special catalyst inside it for that?

On Thu, 25 Oct 2018 16:06:10 +0100, Andy Bennet, another troll-feeding
senile idiot, blathered:


As it spins I think it disperses driver/passenger farts far more
efficiently.

....and troll-feeding senile idiot no.2 appeared to do the Scottish ******
and attention whore the favour he is after! tsk

"Gym Sulkinson Fork" wrote in message
news
Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was
already moving. Surely that's like fitting a generator to your bicycle to
power a motor to make you go faster?

you should worry about something important...tee hee

On Thu, 25 Oct 2018 16:18:54 +0100, Jim GM4DHJ ... wrote:


"Gym Sulkinson Fork" wrote in message
news
Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was
already moving. Surely that's like fitting a generator to your bicycle to
power a motor to make you go faster?

you should worry about something important...tee hee

Like? I wasn't doing anything else at the time, I was waiting for someone to answer their door.

In article ,
says...

Why are these fitted instead of just a stationary vent like you see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was already moving. Surely that's like fitting a generator to your bicycle to power a motor to make you go faster?



They are powered by the wind that is blowing, not wind they are making.

In the case of the van, they are powered by the wind pressure the van
creates when moving.

On Thu, 25 Oct 2018 16:20:54 +0100, Ralph Mowery wrote:

In article ,
says...

Why are these fitted instead of just a stationary vent like you see on caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was already moving. Surely that's like fitting a generator to your bicycle to power a motor to make you go faster?

They are powered by the wind that is blowing, not wind they are making.

Why not just channel the blowing wind where you want it instead of converting energy twice?

In the case of the van, they are powered by the wind pressure the van
creates when moving.

The above link claims it works when stationary too (by wind).

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:20:54 +0100, Ralph Mowery
wrote:

In article ,
says...

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are powered by the wind that is blowing, not wind they are making.

Why not just channel the blowing wind where you want it instead of
converting energy twice?

Because those things are extracting air from the house or van so that isnt
possible.

In the case of the van, they are powered by the wind pressure the van
creates when moving.

The above link claims it works when stationary too (by wind).

Yes it does. You've likely noticed that houses don't actually move very fast
and do have those vents too.

On Thu, 25 Oct 2018 17:04:57 +0100, Rod Speed wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:20:54 +0100, Ralph Mowery
wrote:

In article ,
says...

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are powered by the wind that is blowing, not wind they are making.

Why not just channel the blowing wind where you want it instead of
converting energy twice?

Because those things are extracting air from the house or van so that isnt
possible.

Why is it better to move it out instead of in? It still has to go in somewhere and out somewhere else. Same ventilation takes place overall.

In the case of the van, they are powered by the wind pressure the van
creates when moving.

The above link claims it works when stationary too (by wind).

Yes it does. You've likely noticed that houses don't actually move very fast
and do have those vents too.

I've occasionally seen them on old houses on chimneys. I thought that was to disperse the smoke.

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 17:04:57 +0100, Rod Speed
wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:20:54 +0100, Ralph Mowery
wrote:

In article ,
says...

Why are these fitted instead of just a stationary vent like you see on
caravans?

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was already moving. Surely that's like fitting a generator to your
bicycle to power a motor to make you go faster?

They are powered by the wind that is blowing, not wind they are making.

Why not just channel the blowing wind where you want it instead of
converting energy twice?

Because those things are extracting air from the house or van so that
isnt
possible.

Why is it better to move it out instead of in?

Because the hot air in the roofspace is already trying to get
out and it works better to help it do what its trying to do
than to try to stop it doing what it is already trying to do.

It still has to go in somewhere and out somewhere else.

Yes, but its better to help it move faster in the direction
it already wants to go.

Same ventilation takes place overall.

Nope, you move more hot air when you help it to go
in the direction it already wants to go, with a fan.

In the case of the van, they are powered by the wind pressure the van
creates when moving.

The above link claims it works when stationary too (by wind).

Yes it does. You've likely noticed that houses don't actually move very
fast
and do have those vents too.

I've occasionally seen them on old houses on chimneys. I thought that was
to disperse the smoke.

Nope, its just another example of a wind powered fan which
helps the air in the chimney move the way it wants to go.

On Thu, 25 Oct 2018 11:20:54 -0400, Ralph Mowery, another obviously mentally
handicapped troll-feeding senile idiot, blathered:

They are powered by the wind that is blowing, not wind they are making.

In the case of the van, they are powered by the wind pressure the van
creates when moving.

The Scottish sow, ******, troll and attention whore thanks you nicely for
taking his latest idiotic bait, troll-feeding senile idiot no.3! BG

Gym Sulkinson Fork wrote

Why are these fitted instead of just a stationary vent like you see on
caravans?

They act like a pump.

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was
already moving.

It isnt from the place you want to move it from.

Surely that's like fitting a generator to your bicycle to power a motor to
make you go faster?

Nope, more like using a wind generator to generate
electricity and using the electricity to drive a fan, but
without the losses involved with the electricity
generation and the electrical fan.

On Thu, 25 Oct 2018 16:25:20 +0100, Rod Speed wrote:

Gym Sulkinson Fork wrote

Why are these fitted instead of just a stationary vent like you see on
caravans?

They act like a pump.

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was
already moving.

It isnt from the place you want to move it from.

Surely that's like fitting a generator to your bicycle to power a motor to
make you go faster?

Nope, more like using a wind generator to generate
electricity and using the electricity to drive a fan, but
without the losses involved with the electricity
generation and the electrical fan.

But the point is to move air into or out of (shouldn't matter which, air still goes through the van) where the vent is. Why not just let the wind blow the air into the van? Making that wind turn a vent which then sucks air in is utterly pointless.

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:25:20 +0100, Rod Speed
wrote:

Gym Sulkinson Fork wrote

Why are these fitted instead of just a stationary vent like you see on
caravans?

They act like a pump.

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was
already moving.

It isnt from the place you want to move it from.

Surely that's like fitting a generator to your bicycle to power a motor
to
make you go faster?

Nope, more like using a wind generator to generate
electricity and using the electricity to drive a fan, but
without the losses involved with the electricity
generation and the electrical fan.

But the point is to move air into or out of (shouldn't matter which, air
still goes through the van) where the vent is.

It does actually, particularly when getting it to
remove the hot air in the roof space in summer.

Why not just let the wind blow the air into the van?

Doesn't work when the van is stationary.

Making that wind turn a vent which then sucks air in is utterly pointless.

Wrong. That's the way the hot air in the roof space wants to
go, out of the roof space, and so its better to help it go where
it wants to go, with a fan and have the fan powered by the wind.

Yes, with houses, an electric fan is better, but the big advantage
with those wind powered fans is that its driven by the wind.

On Thu, 25 Oct 2018 17:09:56 +0100, Rod Speed wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:25:20 +0100, Rod Speed
wrote:

Gym Sulkinson Fork wrote

Why are these fitted instead of just a stationary vent like you see on
caravans?

They act like a pump.

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was
already moving.

It isnt from the place you want to move it from.

Surely that's like fitting a generator to your bicycle to power a motor
to
make you go faster?

Nope, more like using a wind generator to generate
electricity and using the electricity to drive a fan, but
without the losses involved with the electricity
generation and the electrical fan.

But the point is to move air into or out of (shouldn't matter which, air
still goes through the van) where the vent is.

It does actually, particularly when getting it to
remove the hot air in the roof space in summer.

but if you let the wind blow it in, then it goes out where it's currently coming in.

Why not just let the wind blow the air into the van?

Doesn't work when the van is stationary.

The same wind that currently spins the vent could do so.

"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 17:09:56 +0100, Rod Speed
wrote:



"Gym Sulkinson Fork" wrote in message
news
On Thu, 25 Oct 2018 16:25:20 +0100, Rod Speed
wrote:

Gym Sulkinson Fork wrote

Why are these fitted instead of just a stationary vent like you see on
caravans?

They act like a pump.

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air
was
already moving.

It isnt from the place you want to move it from.

Surely that's like fitting a generator to your bicycle to power a
motor
to
make you go faster?

Nope, more like using a wind generator to generate
electricity and using the electricity to drive a fan, but
without the losses involved with the electricity
generation and the electrical fan.

But the point is to move air into or out of (shouldn't matter which, air
still goes through the van) where the vent is.

It does actually, particularly when getting it to
remove the hot air in the roof space in summer.

but if you let the wind blow it in, then it goes out where it's currently
coming in.

Yes, but is going against the natural flow of the hot air
coming out of the roofspace, so doesn't work as well.

Think of electrically powered exhaust fans.

The work much getter moving the air out of the roofspace
than moving outside air into the the roofspace.

Makes no difference how that fan is powered,
still works better to move the hot air in the
roofspace in the way it wants to go by convection.

Why not just let the wind blow the air into the van?

Doesn't work when the van is stationary.

The same wind that currently spins the vent could do so.

But with a van, it also works when there is no wind
and the van is moving.

Hang on though, to make it spin it has to have drag. If it has drag its
using fuel. Might be moor efficient then to streamline the van and run the
fan from the van electrics which is there already.
Brian

--
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This newsgroup posting comes to you directly from...
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"Rod Speed" wrote in message
...
Gym Sulkinson Fork wrote

Why are these fitted instead of just a stationary vent like you see on
caravans?

They act like a pump.

http://www.flettner.co.uk/van-roof-vents/

I don't see the point in using the wind to power a vent, when the air was
already moving.

It isnt from the place you want to move it from.

Surely that's like fitting a generator to your bicycle to power a motor
to make you go faster?

Nope, more like using a wind generator to generate
electricity and using the electricity to drive a fan, but
without the losses involved with the electricity
generation and the electrical fan.

But the power taken from the alternator would surely be just as bad as the wind drag? Both are putting extra strain on the engine. I wonder if anyone has ever studied whether you should (for fuel efficiency) open your car window when driving on a hot day or use the cooling fan (ignoring AC for the moment).


On Thu, 25 Oct 2018 17:43:18 +0100, Brian Gaff wrote:

Hang on though, to make it spin it has to have drag. If it has drag its
using fuel. Might be moor efficient then to streamline the van and run the
fan from the van electrics which is there already.
Brian

Gym Sulkinson Fork wrote

But the power taken from the alternator
would surely be just as bad as the wind drag?

No, because of the worse efficiency of going thru the
electricity. Alternators arent anything even remotely
like 100% efficient, and neither are electric fans.

Both are putting extra strain on the engine.

Yes, but not the same extra load, particularly given
that the van is already a considerable extra drag at
anything more than very low road speeds.

I wonder if anyone has ever studied whether you should
(for fuel efficiency) open your car window when driving on a
hot day or use the cooling fan (ignoring AC for the moment).

Yes they have and the Mythbusters tested it too, but ****ed that up a bit.

Brian Gaff wrote

Hang on though, to make it spin it has to have drag. If it has drag
its using fuel. Might be moor efficient then to streamline the van
and run the fan from the van electrics which is there already.

On Thu, 25 Oct 2018 21:19:46 +0100, Rod Speed wrote:

Gym Sulkinson Fork wrote

But the power taken from the alternator
would surely be just as bad as the wind drag?

No, because of the worse efficiency of going thru the
electricity. Alternators arent anything even remotely
like 100% efficient, and neither are electric fans.

Both are putting extra strain on the engine.

Yes, but not the same extra load, particularly given
that the van is already a considerable extra drag at
anything more than very low road speeds.

I wonder if anyone has ever studied whether you should
(for fuel efficiency) open your car window when driving on a
hot day or use the cooling fan (ignoring AC for the moment).

Yes they have and the Mythbusters tested it too, but ****ed that up a bit.

And what was the result?

Brian Gaff wrote

Hang on though, to make it spin it has to have drag. If it has drag
its using fuel. Might be moor efficient then to streamline the van
and run the fan from the van electrics which is there already.

On Fri, 26 Oct 2018 07:19:46 +1100, cantankerous trolling senile geezer Rot
Speed blabbered, again:

FLUSH the two village idiots' endless idiotic drivel unread again

--
Latest retarded conversation between out two village idiots, Birdbrain and
Rot Speed:

Birdbrain: "You beat me to it. Plain sex is boring."

Senile Rot: "Then **** the cats. That wont be boring."

Birdbrain: "Sell me a de-clawing tool first."

Senile Rot: "Wont help with the teeth."

Birdbrain: "They've never gone for me with their mouths."

Rot Speed: "They will if you are stupid enough to try ****ing them."

Birdbrain: "No, they always use claws."

Rot Speed: "They wont if you try ****ing them. Try it and see."

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