who is using, or used CSM540 gyro?

who is using, or used CSM540 gyro?

Post by Jamie Wilso » Tue, 14 Aug 2001 08:21:21



Hi All,

trying to get a feel for what people have experienced with this gyro. I have
bought one, and without going into detail, it is proving very difficult.
Wondering if others have had similar experiences.

Would love to hear about it...

Regards
Jamie Wilson

 
 
 

who is using, or used CSM540 gyro?

Post by Beavi » Tue, 14 Aug 2001 09:26:14




Quote:
>Hi All,

>trying to get a feel for what people have experienced with this gyro. I have
>bought one, and without going into detail, it is proving very difficult.
>Wondering if others have had similar experiences.

I don't fly anything else these days Jamie, basically because they're
ULTRA reliable and "not bad" at holding the tail either :-)

Most of the guys at our field use either the 540 or the 400 and the same
thing applies. Go through the set up procedure, then forget about it.

Mine defies all attempts from me to make the heli "swap ends" when I'm
flying backwards or sideways and you can't really ask for more than
that. I wouldn't swap it for any other gyro I've used anyway (and I've
used one or two)

Beav

You can E-Mail me at the usual place (Beavis at nachos dot demon dot co dot uk)

Or you can visit my website (Which has undergone recent surgery) Same address as
before..

www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by Peter Wale » Tue, 14 Aug 2001 21:40:45


The 540 was the first of the second generation of HH gyros, with drift
elimination. It was developed by Colin Mills and Bob Johnston. If you have
ever seen Bob fly, you will understand why the gyro does what it does. His
helis are dead smooth, his engines run like turbines and the whole assembly
is very rigid. CF tailbooms are out, too flexible.

If your heli is like that, then it will fly like Bob's does. If its not, and
the motor is a little rough, the tail will twitch in sympathy. If there is
anything which can move on the heli, like the battery, it will cause the
heli to overshoot on pirouettes. I have found them less than perfect on
scale helis.

The worst gyro I have found on a scale heli is the 5000G, if the head speed
is slow.

So, give us some details, we may be able to offer more pertinent advice

Peter Wales in wet and windy England

Quote:


> >Hi All,

> >trying to get a feel for what people have experienced with this gyro. I
have
> >bought one, and without going into detail, it is proving very difficult.
> >Wondering if others have had similar experiences.

 
 
 

who is using, or used CSM540 gyro?

Post by Jamie Wilso » Tue, 14 Aug 2001 21:54:23


Hi Beavis,

thanks for ya reply. Well, its got me beat!!  Out the box, the 540 was
basically unusable for me. The tail would wag in hover, and by the time the
gain was reduced enough to stop wagging, tha tail wouldn't hold.

I bought the pc interface and have been messing around for 2 weeks, but with
no success. Maybe it just doesnt like me??  I am trying hard to like it 8-(

FWIW, I am using a 2700g, 105NHP tails, and no boom movement is present. Oh
well, just have a few more things to try out. Then if I can't return
it...............Know anyone in the market for a very near new 540??

Seeya
Jamie

Quote:


> >Hi All,

> >trying to get a feel for what people have experienced with this gyro. I
have
> >bought one, and without going into detail, it is proving very difficult.
> >Wondering if others have had similar experiences.

> I don't fly anything else these days Jamie, basically because they're
> ULTRA reliable and "not bad" at holding the tail either :-)

> Most of the guys at our field use either the 540 or the 400 and the same
> thing applies. Go through the set up procedure, then forget about it.

> Mine defies all attempts from me to make the heli "swap ends" when I'm
> flying backwards or sideways and you can't really ask for more than
> that. I wouldn't swap it for any other gyro I've used anyway (and I've
> used one or two)

> Beav

> You can E-Mail me at the usual place (Beavis at nachos dot demon dot co
dot uk)

> Or you can visit my website (Which has undergone recent surgery) Same
address as
> before..

> www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by A Kraut in Aussielan » Tue, 14 Aug 2001 23:42:02


Agree with Beavy
I have got the same CSM540, on the 1st go it was a ***, wouldn't hold the
tail for anything in the world.
Very disapointing as this was my change to a piezo form a conventional
Futaba BB153.
So I bought a fency (very expensive...Outch) JR 8700 servo...no
difference...read the gyro manual again.
Says something about no movement or slop in tail system....nope, no
slop..but boom can be moved a little from side to side as I have just the
standard single tailboom brace on my X-Cell.
Okay, get a new double graphite brace.....Wow...can't move that tail unless
I say so.
I just set it up as per instruction...haven't touched it since.
Alfred :-)


Quote:
> Hi All,

> trying to get a feel for what people have experienced with this gyro. I
have
> bought one, and without going into detail, it is proving very difficult.
> Wondering if others have had similar experiences.

> Would love to hear about it...

> Regards
> Jamie Wilson

 
 
 

who is using, or used CSM540 gyro?

Post by MArmit10 » Wed, 15 Aug 2001 02:42:10


Quote:
>Hi Beavis,

>thanks for ya reply. Well, its got me beat!!  Out the box, the 540 was
>basically unusable for me. The tail would wag in hover, and by the time the
>gain was reduced enough to stop wagging, tha tail wouldn't hold.

>I bought the pc interface and have been messing around for 2 weeks, but with
>no success. Maybe it just doesnt like me??  I am trying hard to like it 8-(

>FWIW, I am using a 2700g, 105NHP tails, and no boom movement is present. Oh
>well, just have a few more things to try out. Then if I can't return
>it...............Know anyone in the market for a very near new 540??

Jamie,
           I'm sorry to say it sounds like you've been unlucky and got a faulty
gyro.The latest one is my 4th 540  and on installing it into a Concept VR mine
also did exactly as you've just described.The tail pulsed left and right from
centre about 20degrees at an even  slowish  rate,with the gain down at 20% it
still did it by exactly the same amount.The pulsing is a fair bit slower than
the normal hunting i would get with the gain set too high.I know it isn't my
heli as i'd had another 540 in there that i suspected had "gone off" a bit due
to a crash.
.
Send it back and get a replacement,i think you should give it one more chance.
Sorry you've had bad luck,maybe there's some out there that aren't showing up
on their (CSM's)testing,either that or there is something we are both
missing,but my moneys on a gyro fault.I feel a bit guilty as i recommended it
over your Futaba for more consistant piro rates.

Martin

Martin

 
 
 

who is using, or used CSM540 gyro?

Post by Beavi » Tue, 14 Aug 2001 23:13:52




Quote:
>The 540 was the first of the second generation of HH gyros, with drift
>elimination. It was developed by Colin Mills and Bob Johnston. If you have
>ever seen Bob fly, you will understand why the gyro does what it does. His
>helis are dead smooth, his engines run like turbines and the whole assembly
>is very rigid. CF tailbooms are out, too flexible.

Have you seen the high modulus carbon fibre booms Pete. (Can't ***y
remember who makes the things, but Revo sell 'em) They flex "somewhat"
less than the standard ali booms but at 40 quid a pop, they're probably
not for everyone.

Also, I suspect one of the reasons that Bob uses a standard boom is
because he's representing Robbe when he flies, so he can't really be
seen to be fitting after market (particularly non Robbe parts) to what
are ostensibly high spec "ready to leather" machines. My boom is
standard (as is every other part for that matter) and I couldn't wish
for more though.

Quote:

>If your heli is like that, then it will fly like Bob's does. If its not, and
>the motor is a little rough, the tail will twitch in sympathy. If there is
>anything which can move on the heli, like the battery, it will cause the
>heli to overshoot on pirouettes. I have found them less than perfect on
>scale helis.

I know I said I use nothing else, but I was referring to aerobatic
machines and so I didn't "factor in" the scale models I fly.  In them I
don't use HH gyro's at all, just good piezo gyro's (JR 900's as it
happens)

Quote:

>The worst gyro I have found on a scale heli is the 5000G, if the head speed
>is slow.

Not tried one, but as it's a HH, I wouldn't anyway. I like the tail to
follow the nose without any input (well ALMOST none) from me.

Beav

You can E-Mail me at the usual place (Beavis at nachos dot demon dot co dot uk)

Or you can visit my website (Which has undergone recent surgery) Same address as
before..

www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by Beavi » Tue, 14 Aug 2001 23:26:19




Quote:
>Hi Beavis,

>thanks for ya reply. Well, its got me beat!!

I'm intrigued. So far they've been THE easiest to set up and use of ANY
gyro I've ever played with.

Quote:
>  Out the box, the 540 was
>basically unusable for me. The tail would wag in hover, and by the time the
>gain was reduced enough to stop wagging, tha tail wouldn't hold.

Let me tell you how my "system" is set up. First of all I don't use the
highest speed servo's out there. The one on my Futura is a JR 4000 Super
Servo (strong, but not particularly quick in comparison to the 2700 and
the 8700). The one on my Space Baron/Enforcer is a SuperTec, which is
quick but not blistering. Servo arm length on both is 15mm from servo
centre to ball link centre. Gain in both non heading hold and HH is 95%
on the Futura (can't remember what it is in the Space, but it's
similar). Not a TRACE of a wag and neither of these heli's will swap
ends no matter how hard I try, and some of the "situations" I get my
heli's in put a bit of a strain on the tail.

Quote:

>I bought the pc interface and have been messing around for 2 weeks, but with
>no success. Maybe it just doesnt like me??  I am trying hard to like it 8-(

I've only ever LOOKED at the programming on the PC Jamie, I've never
changed anything and neither has anyone else at our field. No-one's had
an ounce of trouble, once the gyro's been set up properly. I'm not
saying you DON'T set it up properly, but it's a possibility. Some of the
heli's I've done the set up procedure on have been "done" before

Quote:

>FWIW, I am using a 2700g,

Well your problem shouldn't be coming from the servo, but you never
know. Have you tried a different (maybe a slower) one?

Quote:
>105NHP tails,

I originally used NHP tails on the Futura at 92mm, with no problem, (a
consideration??) but I lent them to another flyer and they died. He
replaced them with a pair of MS tails at 105(ish) and I could crank up
the gain a little to it's present 95%.  What heli are you flying btw?

Quote:
> and no boom movement is present. Oh
>well, just have a few more things to try out. Then if I can't return
>it...............Know anyone in the market for a very near new 540??

Yeah, me, but before you REALLY decide to bin it, let CSM have a look at
it. It could be a faulty unit after all.

Later

Beav

You can E-Mail me at the usual place (Beavis at nachos dot demon dot co dot uk)

Or you can visit my website (Which has undergone recent surgery) Same address as
before..

www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by Peter Wale » Wed, 15 Aug 2001 05:28:44


I cant say I have seen anything CF which claims to be less flexible than
ally Beav, but then since Bob warned me off the CF booms I haven't looked. I
have a brand new CF boom in my junk box looking forlorn.

Bob did try the CF booms, he was working for Revolution at the time. He also
was involved in the design and  development of the CF side frames Revolution
sell. I believe he still uses them. It may be that they supply them to Robbe
to relabel and sell as original equipment.

Bob is interested in the best flying heli, and he'll try anything to get
there. Whether its still on his heli when he does a "public" demo is another
story.

Everything I have has a HH gyro in permanent HH mode......but I think we had
this discussion once before didn't we? <G>

Peter Wales in wet and windy England


Quote:


> >The 540 was the first of the second generation of HH gyros, with drift
> >elimination. It was developed by Colin Mills and Bob Johnston. If you
have
> >ever seen Bob fly, you will understand why the gyro does what it does.
His
> >helis are dead smooth, his engines run like turbines and the whole
assembly
> >is very rigid. CF tailbooms are out, too flexible.

> Have you seen the high modulus carbon fibre booms Pete. (Can't ***y
> remember who makes the things, but Revo sell 'em) They flex "somewhat"
> less than the standard ali booms but at 40 quid a pop, they're probably
> not for everyone.

> Also, I suspect one of the reasons that Bob uses a standard boom is
> because he's representing Robbe when he flies, so he can't really be
> seen to be fitting after market (particularly non Robbe parts) to what
> are ostensibly high spec "ready to leather" machines. My boom is
> standard (as is every other part for that matter) and I couldn't wish
> for more though.

> >If your heli is like that, then it will fly like Bob's does. If its not,
and
> >the motor is a little rough, the tail will twitch in sympathy. If there
is
> >anything which can move on the heli, like the battery, it will cause the
> >heli to overshoot on pirouettes. I have found them less than perfect on
> >scale helis.

> I know I said I use nothing else, but I was referring to aerobatic
> machines and so I didn't "factor in" the scale models I fly.  In them I
> don't use HH gyro's at all, just good piezo gyro's (JR 900's as it
> happens)

> >The worst gyro I have found on a scale heli is the 5000G, if the head
speed
> >is slow.

> Not tried one, but as it's a HH, I wouldn't anyway. I like the tail to
> follow the nose without any input (well ALMOST none) from me.

> Beav

> You can E-Mail me at the usual place (Beavis at nachos dot demon dot co
dot uk)

> Or you can visit my website (Which has undergone recent surgery) Same
address as
> before..

> www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by Beavi » Wed, 15 Aug 2001 06:49:13




Quote:
>I cant say I have seen anything CF which claims to be less flexible than
>ally Beav, but then since Bob warned me off the CF booms I haven't looked. I
>have a brand new CF boom in my junk box looking forlorn.

I've not been an advocate of CF booms since the days of the Baron 60
Pete, but the ones ate Revo are a magnitude more rigid. They've got a
Heath Robinson "test-rig" where three booms can be fitted next to each
other. Then they hang a brick on the other end of each boom. The
"normal" carbon boom bends down, as does the standard Futura boom, but
the "high modulus" item resists the weight a lot better and hardly bows
at all.

Quote:

>Bob did try the CF booms, he was working for Revolution at the time.

These aren't made by Revo/NHP though, and I "think" Bob had gone to his
new pastures before these booms were available.

Quote:
> He also
>was involved in the design and  development of the CF side frames Revolution
>sell. I believe he still uses them. It may be that they supply them to Robbe
>to relabel and sell as original equipment.

Possibly, but I'm not sure one way or t'other.

Quote:

>Bob is interested in the best flying heli, and he'll try anything to get
>there. Whether its still on his heli when he does a "public" demo is another
>story.

That's the thing. As far as I know, he doesn't use anything that doesn't
come in the box, but that's for demo flying. I can't see him NOT
experimenting with new and possibly better stuff when he's not "on air
though.

Quote:

>Everything I have has a HH gyro in permanent HH mode......but I think we had
>this discussion once before didn't we? <G>

Likely as not :-)

Beav

You can E-Mail me at the usual place (Beavis at nachos dot demon dot co dot uk)

Or you can visit my website (Which has undergone recent surgery) Same address as
before..

www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by Ivan Trai » Thu, 16 Aug 2001 04:39:39


Sorry to change the subject, but I am using a 540 and really like it, but
the til drifts, Is there anything I should look out for?

As it is, i have a carbon boom, which is about the same stiffness as the
stock ali boom, but much lighter.

Bob J's page says that it will only drift with severe temp changes, but mine
doesn't care.  it drifts all the time.  It will drift either way, and change
during one tank of fuel.

I just tried the "optimise for medium vibration environment" opiton, in a
fit of frustration, and will see how it works the next time the wind falls
below half gale.

Another question, do you take all the heading hold relaxation rate out on HH
mode?

I had mine set to about 3% and it would weathervane into the wind ever so
slowly.  I also turned that down to .5%.  Maybe these two are interrealted?

Thanks for putting up with my rambling,
Ivan

 
 
 

who is using, or used CSM540 gyro?

Post by Ivan Trai » Thu, 16 Aug 2001 04:41:15


I had the same problem, with a 2700 and 105 NHP's.  Try shortening your
servo arm.  that cured the wag for me.

Ivan

Quote:
> Hi Beavis,

> thanks for ya reply. Well, its got me beat!!  Out the box, the 540 was
> basically unusable for me. The tail would wag in hover, and by the time
the
> gain was reduced enough to stop wagging, tha tail wouldn't hold.

> I bought the pc interface and have been messing around for 2 weeks, but
with
> no success. Maybe it just doesnt like me??  I am trying hard to like it
8-(

> FWIW, I am using a 2700g, 105NHP tails, and no boom movement is present.
Oh
> well, just have a few more things to try out. Then if I can't return
> it...............Know anyone in the market for a very near new 540??

> Seeya
> Jamie




> > >Hi All,

> > >trying to get a feel for what people have experienced with this gyro. I
> have
> > >bought one, and without going into detail, it is proving very
difficult.
> > >Wondering if others have had similar experiences.

> > I don't fly anything else these days Jamie, basically because they're
> > ULTRA reliable and "not bad" at holding the tail either :-)

> > Most of the guys at our field use either the 540 or the 400 and the same
> > thing applies. Go through the set up procedure, then forget about it.

> > Mine defies all attempts from me to make the heli "swap ends" when I'm
> > flying backwards or sideways and you can't really ask for more than
> > that. I wouldn't swap it for any other gyro I've used anyway (and I've
> > used one or two)

> > Beav

> > You can E-Mail me at the usual place (Beavis at nachos dot demon dot co
> dot uk)

> > Or you can visit my website (Which has undergone recent surgery) Same
> address as
> > before..

> > www.nachos.demon.co.uk

 
 
 

who is using, or used CSM540 gyro?

Post by MArmit10 » Thu, 16 Aug 2001 10:44:44


Quote:

>Sorry to change the subject, but I am using a 540 and really like it, but
>the til drifts, Is there anything I should look out for?

>As it is, i have a carbon boom, which is about the same stiffness as the
>stock ali boom, but much lighter.

>Bob J's page says that it will only drift with severe temp changes, but mine
>doesn't care.  it drifts all the time.  It will drift either way, and change
>during one tank of fuel.

Ivan,
        Lots of trim shifting from left to right (or vice versa)as the tank
empties is usually vibration related,assuming you're not getting vastly varying
headspeeds.It could be due purely to setup but it can also mean the sensor is
on it's way out and has become
hyper to vibration level changes.The same gyro may work better on another heli
but if it doesn't it may need a new sensor and re-calibration by CSM.

Quote:
>I just tried the "optimise for medium vibration environment" opiton, in a
>fit of frustration, and will see how it works the next time the wind falls
>below half gale.

That may improve it though i leave mine at the std settings.If it WAS
originally working good and now it isn't, it usually means something else has
changed,if it's vibration you're better off tracking that down and using the
gyro as a guide,rather than trying to mask over it and hope it goes away.

Quote:
>Another question, do you take all the heading hold relaxation rate out on HH
>mode?

I don't, though i think you can improve the lock response time around centre by
taking all the relaxation out.One of the improvements over the 360 was that it
tended not to creep the servo across to one side with the heli static,if you
take all the relaxtion out it will start to do this like the 360 did

Quote:
>I had mine set to about 3% and it would weathervane into the wind ever so
>slowly.  I also turned that down to .5%.  Maybe these two are interrealted?

If you hovered side on to a steady breeze (but not gusty)and then neutralised
the rudder stick,having only a few percent of relaxation would make the
trimshift slowly back to the normal mode neutral,however if you've got the
tailblade length optimised it should still more or less hold it's yaw attitude.
If at this point you switch between modes and see a big difference in yaw rate
with no rudder input,it can also be an early  sign that the sensor is getting
tired from being subject to long term vibration.This is assuming it used to do
better in this test and nothing else has changed on your setup.

Martin

 
 
 

who is using, or used CSM540 gyro?

Post by Ivan Trai » Thu, 16 Aug 2001 06:40:14


Hmmm, The gyro is new, or very close, I think about 7gallons and no crashes.
The enigne is the same age.  I have eliminated the slop from the linkages.

The vibrations you speak of, would they be engine or head realated?  I have
balanced the clutch and hub, along with the tail.  I checked my NHP's on a
Koll balancer.   The tail doesn't dance like a rough running engine might
cause, and the drift has been there since day one.

It is most noticable when you land and adjust trim, with the headspeed still
up, and take off again after 5-10 seconds.  the trim will usually require
half or better throw after that.

Quote:

> Ivan,
>         Lots of trim shifting from left to right (or vice versa)as the
tank
> empties is usually vibration related,assuming you're not getting vastly
varying
> headspeeds.It could be due purely to setup but it can also mean the sensor
is
> on it's way out and has become
> hyper to vibration level changes.The same gyro may work better on another
heli
> but if it doesn't it may need a new sensor and re-calibration by CSM.

> >I just tried the "optimise for medium vibration environment" opiton, in a
> >fit of frustration, and will see how it works the next time the wind
falls
> >below half gale.

> That may improve it though i leave mine at the std settings.If it WAS
> originally working good and now it isn't, it usually means something else
has
> changed,if it's vibration you're better off tracking that down and using
the
> gyro as a guide,rather than trying to mask over it and hope it goes away.

> >Another question, do you take all the heading hold relaxation rate out on
HH
> >mode?

> I don't, though i think you can improve the lock response time around
centre by
> taking all the relaxation out.One of the improvements over the 360 was
that it
> tended not to creep the servo across to one side with the heli static,if
you
> take all the relaxtion out it will start to do this like the 360 did

> >I had mine set to about 3% and it would weathervane into the wind ever so
> >slowly.  I also turned that down to .5%.  Maybe these two are
interrealted?

> If you hovered side on to a steady breeze (but not gusty)and then
neutralised
> the rudder stick,having only a few percent of relaxation would make the
> trimshift slowly back to the normal mode neutral,however if you've got the
> tailblade length optimised it should still more or less hold it's yaw
attitude.
> If at this point you switch between modes and see a big difference in yaw
rate
> with no rudder input,it can also be an early  sign that the sensor is
getting
> tired from being subject to long term vibration.This is assuming it used
to do
> better in this test and nothing else has changed on your setup.

> Martin

 
 
 

who is using, or used CSM540 gyro?

Post by Beavi » Thu, 16 Aug 2001 10:20:56




Quote:
>Sorry to change the subject, but I am using a 540 and really like it, but
>the til drifts, Is there anything I should look out for?

Ivan, the original heading hold gyro (the CSM ICG 360) was reputed to
have a drift "problem", but the next generation (the 540) had built in
compensation for drift and as far as I've been able to establish, it
worked (works) 100%. I can't say any more than I NEVER touch the tail
rotor trim lever on my most used heli.

Now this isn't to say you're NOT getting a drift, but it's where the
drift "command" is coming from that may need investigating. If there's
ANY trim used, and that includes any SUB-TRIM, then the gyro will see
this as a command to do something. I first make sure there's no trim or
sub-trim and no other mixing that could affect the tail. Then I set the
tail rotor pitch at around 8 degrees and then take off. ANY movement of
the tail is dealt with by adjusting the pushrod. That's it then, I never
touch it again.

If you did all of the above and you're STILL getting a drift, you may
well have a gyro in need of attention.

Quote:

>As it is, i have a carbon boom, which is about the same stiffness as the
>stock ali boom, but much lighter.

Shouldn't make the tail drift even if it's not AS stiff, but I hope you
have boom struts too.

Quote:

>Bob J's page says that it will only drift with severe temp changes, but mine
>doesn't care.  it drifts all the time.  It will drift either way, and change
>during one tank of fuel.

In that case, I'd say it probably needs looking at by CSM.

Quote:

>I just tried the "optimise for medium vibration environment" opiton, in a
>fit of frustration, and will see how it works the next time the wind falls
>below half gale.

Our wind dropped tonight. Just as the sun did :-))

Quote:

>Another question, do you take all the heading hold relaxation rate out on HH
>mode?

No. Mine is absolutely bog standard. I thought that Colin Mill must know
a bit more about gyro's then me, so I went with what he decided was a
good compromise, and so it turned out (for me). All settings are "as
was" and that's all I've needed.

Quote:

>I had mine set to about 3% and it would weathervane into the wind ever so
>slowly.  I also turned that down to .5%.  Maybe these two are interrealted?

If it can weathervane it WILL, so if your drift problem is "with" the
prevailing wind, then that could be the prob. Do you remember the
original relaxation rate percentage? If so you could try re-setting it
back and trying again.

Quote:

>Thanks for putting up with my rambling,

Not rambling when we're trying to get to the bottom of a problem,
particularly when one of us IS having a prob and the other isn't. Once
again, all I can say about the 540 is it's never let me down, even when
it had every right too.

Beav

You can E-Mail me at the usual place FOR NOW, but not for long:)

(Beavis at nachos dot demon dot co dot uk)

Or you can visit my website (Which has undergone recent surgery) Same address as
before..

www.nachos.demon.co.uk