Windslammer

Apr 10, 2006
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I have an eighties car/caravan combination wondered if a windjammer or similar roof mounted aerofoil would help improve fuel consumption when towing - anybody know if they are still available and where from - any advice would be appreciated - new to caravanning
 
May 21, 2008
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Hi Bob.

I actually use one of these on my Laguna while towin our Link 575 which is a 24 year old 20 foot twin axle van.

I get improved top speed by about 7Mph and a fuel improvement of about 5 Mpg.

Got mine from a boot sale for
 
Jan 2, 2006
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I had a windslammer years ago when they were the 'in' thing to have,but if I am honest it made no difference whatsoever and I recall at the time that there was much debate about these.

It revolved around the correct angle to set it to,too low and it does nothing ,too steep and its like an airbrake.The other point was they were a pain in the .... to fit and many people didnt take them off when solo which negated any benefit that they may have had,but each to their own.
 
Mar 14, 2005
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I used to think that a windslammer was beneficial with improved mpg and ease of holding cruising speed

They seem to have gone out of fashion now.

I had concerns that the air channeled over the roof might affect caravan stability after reading a review with tests of the aerofoil type that mounted on the back bumper.

Never did see many of those about .
 
Jan 2, 2006
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Nothing to do with windslammers but sad person that I am I also had indeed still have a retrovisor which was supposed to act like a periscope and give through the van vision,which it did once you managed to get it adjusted.
 
Mar 14, 2005
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I don't know much about the Windslammer but when I tow with the roof box on the car I seem to get slightly better MPG, does anyone else seem to find this?
 
Mar 14, 2005
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BOB

Sorry about that last one - fat finger trouble. If you want to try a windslammer (I had one many years ago, and it did what it was supposed to) you can make one easily.

Using a roofrack crossbar, sort out a piece of ply, or similar, about a foot high and as wide as your roofrack, angle it initially about 45degrees, place it about over car rear wheels.

Then adjust it - ideally with about 20feet of knitting wool attached to the car bonnet, and viewed by a pedestrian partner at the side of the road as you drive by ideally at your towing speed. When it is at the correct angle, and in the right place on the car, the wool will flow over the car and then over the van. If you can't do it this way, just watch for the dead flies on the van roof, and fiddle till they are all blown over the top! Enjoy.
 
Mar 14, 2005
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Hi Bob

The concept behind the Windslammer and other similar products was to try to create a smoother air flow over the car and caravan combination. Provided the placement is correct then some improvement may be possible, but get the position or angle wrong and the product may actually make the outfit worse.

Normally you would need to use a wind tunnel and smoke trails to optimise the fitting, but Peter T's suggestion of using a long piece of wool is an interesting and simple suggestion, It is the same principal that sailors use, where short lengths of cord are incorporated into the surface of a sail, and if the airflow over the sail is smooth, the tell tales flare out relatively steadily. Observing the tell tales can help them to trim the sails for maximum effect.
 
Mar 14, 2005
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Hi,

The winslammer was manufactured by a company called Bumper to Bumper based in Warrington, Cheshire. The company had the slammer designed for HGV cab units to deflect windflow over the trailer unit.Then it was reduced in size to accomadate caravans.The unit was wind tunnel tested at UMIST in manchester and if the angle was correct it did improve windflow and reduced buffeting between the vehicle and the van. Yes as vehicles appeared with gutterless roofs it became more difficult to fit the windslammer and led to its demise. Bumper to Bumper suppied tow bars,bike carriers, hitch locks, wheel clamps, security posts etc. I used to be the sales manager for them and left their employ some 10 years ago and the company folded some 18 months later.Trying to source one nowadays could be difficult but you could try the J.R Group, CCC at Sheffield or any other caravan dealer who used to source through Burdens or Riddioughs.

Rob
 
May 21, 2008
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I should of added to the original reply, when I had a Renault 25 to tow the same van, without the wind jammer it would not tow safely above 55Mph.

Someone mentioned the flyless benifit, that is true and it also indicates that the job is being done.

True they are a fiddle to set to the optimum, but once done if you put a small dot of permanent marker on the roof bar, or gutter you can reset each time quickly.
 
Dec 16, 2003
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Still have a Windslammer allthough not used with People Carrier.

Last used on Volvo estate and without it on the car used more fuel and cruising speed was lower.

Effective with an Estate car but not to effective on a saloon as the "wing" is to far from the van!

Angle should not be to steep, if it is the air spirals downwards off the top edge. An angle towards the vans roof line that lets the air flow upwards and over the roof works quite well.
 
Apr 10, 2006
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Still have a Windslammer allthough not used with People Carrier.

Last used on Volvo estate and without it on the car used more fuel and cruising speed was lower.

Effective with an Estate car but not to effective on a saloon as the "wing" is to far from the van!

Angle should not be to steep, if it is the air spirals downwards off the top edge. An angle towards the vans roof line that lets the air flow upwards and over the roof works quite well.
Thanks to all for your helpfull comments - its a pity they are no longer available as I would like to try one - will keep checking e-bay and keep an eye out at car boot sales. Liked the improvised wind tunnel test with the wool. Anything that might help wring a few more miles per very expensive gallon out of the old girl (Passat Estate) is worth a try. I am a newcomer to this caravan lark having just graduated from tents - cheers
 
Apr 10, 2006
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Thanks to all for your helpfull comments - its a pity they are no longer available as I would like to try one - will keep checking e-bay and keep an eye out at car boot sales. Liked the improvised wind tunnel test with the wool. Anything that might help wring a few more miles per very expensive gallon out of the old girl (Passat Estate) is worth a try. I am a newcomer to this caravan lark having just graduated from tents - cheers
 
Mar 14, 2005
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I, too, noticed that I got better M.P.G. with a roof box on which seems odd. Then I realised I only used the roofbox when going on holiday doing long steady runs rather than the usual local stuff.
 
Nov 6, 2005
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Windslammers were only effective in reducing overall drag when fitted right at the back of an estate car, and then only when set at the right angle which is difficult to do. If set further forward or at the wrong angle they actually increased drag.

Some years ago Bath University did some research, sponsored by the Caravan Club, into caravan aerodynamics and stability. They found that the dynamic extra downforce on the hitch from the sloping front of modern caravans aided stability. Fitting windslammers reduced this downforce and reduced stability which is why the CC withdrew recommendations on their use.
 

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