Wind deflectors

[John_5040781]

I have just been given an old windslammer deflector. It is designed to be fitted on cars with gutters, which my Passet Estate does not have. I have read all the comments about deflectors and would like to try this one, being the free option
Can any one suggest how this could be modified to fit roof bars?

 

[emmerson]

It should be easy, as the shield itself is fitted on what is in effect, a roof bar. Simply adapt the fittings to suit.
I use one occasionally on my Range Rover classic, but the only difference I notice is that there are less bugs on the front of the van after a long fast European run.
I suppose, though, that that is an indication that the deflector is doing its job!

 

[birdman101]

A lot of us had them 35-40 years ago,and they need to be as close to the roof as possible which may present a problem mounting on roof bars unless you can adapt to fit, to fill in open area below.They prevented less fly splats as above post but never improved my fuel consumption.

 

[anotherDavid]

Unless you think its worth it for the insects I wouldnt bother. Years ago I had a fairly basic metal plate that I did think worked however a couple of years ago I bought one of the latest plastic models that really looks the part and I dont think it makes a smite of difference to fuel consumption. It can be adjusted to 3 positions and I tried all of them on runs of several hundred miles each we kept note (allways do) of MPG and came to the conclusion it had been a waste of money.

 

[colin-yorkshire1]

hi John,
interesting replies, I would not go so far as to say as a piece of equipment a windslammer was a waste of time and money,
but and it is a big but, it depends how and when it is used, this is the key, true they were very popular 30/40years ago and for good reason the shape and design of caravans was vastly different from whats on the market today. Emmerson makes a good point on this which I understand because he tows a classic caravan for long distances, the fact that it defelcts bugs shows it works.
I would however discount any claims that it would save very much fuel. in all the years I used one it made no difference however it did improve the ride comfort when towing in a head wind, and in general terms might have improved stability in some cases but that depends on many factors, type of tow vehicle, size weather conditions, ect ect. but i am sure you are well aquainted with all this.

now for the question, can it be modified to fit your car yes of course it can there are two ways to do it,
1. remove the blade from its fixings and mount it on a standard bar that fits your car using small U bolts. or
2. get a set of fixings that fit the car and mount the complete bar to these,
however there is a problem, the windslammer was designed to fit as far back on the towing vehicle as required and at the right angle to deflect the air flow over the caravan, with cars that had roof gutters this was easy as it could be positioned anywhere along the back end of the vehicle, but cars with no gutter tend to have fixed bar positions these may well be too far forwards for the blade to work, it depends where these points are on your car.
it may well be possible to obtain clamp type fixings that do not use the fixed points of the car but grip the roof corner and and have a pad that sits on the roof channel rubber "seen these in halfords" or if one of your type of car models have fixed full length longtitudal rails you know the type I mean

a cross grip bar can be used anywhere along its length to mound the blade on.
so it can be done however although the blade was free,

fitting it could cost money

make sure that it can be fitted it the right place. before starting.
good luck colin.

 

[Gafferbill]

Points you might want to consider before the hassle of modification.......

....... fitting a wind deflector only when you are towing your caravan would be a hassle.
........storage and security at a camp site would be a hassle.
.......the only advantage would be a possible reduction in fuel costs.
.......the saving would probably amount to less than £5.00/year if you only tow for the average typical mileage.
.......you could easily better this saving by accelerating more gently and reducing your top speed when towing your caravan.

 

[GrahamDerby]

I used to use one on my Austin Maxi many many years ago, i still have it in the garage !!. You had to set it up by driving with the van on and check if there were fly's on the van window, if there were you had to move it back or forward till you had a clean window . Storing on site was no problem as it went under the van.

 

[colin-yorkshire1]

I used to use one on my Austin Maxi many many years ago,

hi, so did I Graham, from 1972 to 1977, best tow car ever used, bar none however vans were a lot lighter then??.
by the way did your floor fall out, mine did it was 6years old, ooops.

 

[Raywood]

We used one many years ago when I towed a flat fronted Piper with an Escort hatchback. With the windslammer right back and the very poor aerodynamics of the Piper there was a modest fuel saving. We sold the Piper and got a far more streamlined Trophy which we towed with a Cavalier saloon. At that point with the Windslammer well clear of the caravan and the better shape of the caravan I gave up as there was no noticeable saving although it did keep the flies off the front. I did read that it tends to force the rear wheels down rather than save fuel.
It did help find the car in Alton Towers massive car park when we visited there although I normally took it off when on site, we were staying nearby for only the two nights and I had not bothered.

 

[TopCat1]

When you think how much money and time is spent in wind tunnels by car manufacturers then you can get some idea how technically difficult it is to improve the aerodynamics of a vehicle. Small tweaks here and there make huge differences to airflow, noise and drag reduction etc. I cant see any way that a general 'add on' item that has not been tuned to the vehicle body shape can hope to make any difference to fuel consumption. In general therefor they are only any guaranteed use as bug catchers.

 

[Gybe]

When you think how much money and time is spent in wind tunnels by car manufacturers then you can get some idea how technically difficult it is to improve the aerodynamics of a vehicle. Small tweaks here and there make huge differences to airflow, noise and drag reduction etc. I cant see any way that a general 'add on' item that has not been tuned to the vehicle body shape can hope to make any difference to fuel consumption. In general therefor they are only any guaranteed use as bug catchers.

Car manufacturers spend money on car aerodynamics, not car and caravan aerodynamics. A slippery car solo is what they deliver, as soon as you hitch a brick to the back you're on your own. You've altered the cars dynamics completely, There's no reason why an attached wing smoothing the airflow towards the caravan can't be beneficial. getting the right angle and how much difference you can make is down to trial and error.
A wing angle that gently lifts the airflow at the rear of the car towards the caravan roof line should be benenficial, set a steep angle and air will just spiral down behind the car and hit the caravan, a problem many saloons have compared to hatches and estates when towing.

 

[Steve L]

I have converted my wind deflector very easily and cheaply to fit on roof bars. First off I assume the passat has got standard longitudinal roof rails. You can either get the manufacturers cross bars or use generic ones from halfords.
I fitted two aluminium box tube pieces to the wind jammer original mounts that were used on the old roof bars. These were made from 50mm by 25mm box section and cut at 150mm long. This gave me a flat platform to sit on the new cross bars. I fitted the car roof bars to the car just behind the rear passenger door area. I fitted the bars so that there was about 10mm gap between front and back bar. I drilled and fitted a 10mm roofing bolt to fit through the aluminium platform and porject below the bottom of the roof bars. I cut two more aluminium box tube sections and drilled a 10mm hole central in them to make a clamp bar from them. Now all I need is a 17mm spanner to undo just 2 nuts to remove the wind jammer and leave the roof bars in place. I then marked the roof bar positions with electrical tape so that I can refit quickly.
Overall, I have gained between 5 and 7 mpg by towing with a wind deflector while towing caravans and van trailers. So for a few mins of time taken to fit it a deflector you can save a significant amount of fuel costs.
On the subject of aerodynamics, cars are very well designed to run on their own but most car manufacturers only design the safe towing capacityfor the car. Basically you have to manage any aerodynamic additions. A good example of this is haulage company's who do long distance haulage. They pay considerable attention to how fuel efficient the vehicle is and they also train their drivers to be at the top of their game and not waste fuel by driving badly.
These air deflectors are only a generic aid but as such they do offer fuel savings and even if they only catch bugs, they would stop stone chips hitting the caravan. They also can help to some extent with stability while towing. I certainly found these benifits when towing a 19ft twin axle van behind a Renault 25 and a laguna estate. Without the deflector fitted to the 25 hatchback, the caravan was very slugish behind the car.

 

[Parksy]

A good way to save on fuel costs would be to de-clutter the car and caravan so that you are not hauling items that you wont use around with you, check the car and caravan tyre pressures for correct inflation and use some of the economy driving tips such as driving smoothly by not using excessive acceleration or braking.

 

[Gybe]

Admirable advice Parksy but bad aerodynamics of a brick in tow will still not be counteracted by economy driving tips. Obviously a lightweight right foot and good practice will help, in a strong head wind the brick effect is still a problem.
Towing the same caravan with a saloon car and then towing it with an estate version of the same car. Towing with the heavier estate we got more MPG although less than the saloon when solo. Wife and I both found that with estate cars you feel the caravan less in head winds.
Towing work box style trailers with a Navara pickup before a truckman top was fitted was a very unfriendly and fuel guzzling experience compared to with a top fitted over the pickup bed, Filling the gap between tow vehicle and trailer as much as possible and keeping air turbulence out of the gap between the two helps mpg and the ride and can even reduce the need to change down a gear in windy conditions.

 

[Parksy]

In my particular case the brick shape is my Mitsubishi 4x4 and the caravan is more rounded at the front. Under normal driving conditions there is very little difference in mpg either towing or solo. Shoguns and their imported counterpart Pajeros are notorious gas guzzlers but with a combined weight of some 3.5 tonnes for my outfit I can't really grumble at around 24mpg on an automatic transmission 2.8 td.
I tend to be more of a fair weather caravanner these days but obviously strong head winds will affect the mpg, unfortunately I very much doubt if a wind deflector on my combination would be of much help.

 

[otherclive]

The mpg difference between towing with the XC70 and Pajero is about 4mpg in favour of the Volvo. However it's not really a valid comparison since the 18 year old Pajero gets treated with a bit more deference given her advanced years. Although motorway cruising speed for both is around 60 mph I give the old girl more time to get there, and she does spend more time running with the 'big fellas' in lane 1, but overall journey times aren't that disimilar.......... Such is progress!!!

 

[colin-yorkshire1]

hi guys, with respect I think you are missing the point of a wind deflector, and I find myself in complete agreement with Gybe on this,
Parksy hit on the crux of the matter when he mentioned the Pajero being the brick at the front, the aerodynamics are the key it is not a matter of power or weight but the air flow surrounding the unit under tow.
a high roof is better than a low one for instance the Meriva tows far better than the Megane or Mondeo ever did yet is has a smaller engine and less power to weight,, than either of the other two towing the same van, because the air flow is better around the unit,
it is also the reason HGV's have a deflector mounted on the cab of the tractor unit, it stops the airflow hitting the trailer full on creating a sort of air brake in a head wind and considering that the vehicle is moving while under tow this is all the time,
while Gybe is right in that vehicle manufacturers spend a lot of time and effort into arodynamics it is all related to the vehicle being solo as soon as a trailer is put on the back the calculations are meaningless.
all a wind deflector does is spoil the airflow at the back of the vehicle creating a hole for the trailer to run in, in the same way that a F1 car gets a tow from the car in front by running in the hole behind it.
towing with a Shogun or Sorento and other such vehicles the effect would be minimal but towing with a saloon like a Mondeo, Laguna, or Passat it could make a difference, if mounted in the right place,

 

[Gafferbill]

.....it is a well known fact among HGV owners that the best way to save fuel with a vehicle that is obviously not aerodynamic is to slow down.


I could get a 14% decrease in fuel consumption from my fully air kitted 38ton Volvo artic by running at 50mph rather than 56mph.
I disciplined myself to do this as it did not affect journey times by that much and it increased my profit by £6000.00/year for no cost input. (over 80,000miles/year)

Trying to streamline a car/caravan outfit is a waste of time mainly due to the low annual mileages involved making any savings minimal.
If you want fuel savings just slow down

 

[Parksy]

.....it is a well known fact among HGV owners that the best way to save fuel with a vehicle that is obviously not aerodynamic is to slow down.


I could get a 14% decrease in fuel consumption from my fully air kitted 38ton Volvo artic by running at 50mph rather than 56mph.
I disciplined myself to do this as it did not affect journey times by that much and it increased my profit by £6000.00/year for no cost input. (over 80,000miles/year)

Trying to streamline a car/caravan outfit is a waste of time mainly due to the low annual mileages involved making any savings minimal.
If you want fuel savings just slow down

I agree completely and as an HGV driver back in the day we could earn part of our bonus by lowering fuel consumption by reducing speed by a few mph in the days before speed limiters were fitted to lorries.
I'm lucky enough to live close to the central motorway network and I'm happy to poodle along the M5 with the trucks. On very windy days it's possible to reduce the effect of headwinds on the caravan when travelling behind a large truck and trailer

 

[Raywood]

I have to agree that wind deflectorsare probably not cost effective. The power needed to overcome wind resistance roughly doubles with every extra 10 mph so reducing speed is the best way to save when driving.

 

[Gybe]

Trucks are designed, power rated and geared for carrying weight at moderate speed. Tow cars are made for travelling at higher speeds without a brick in tow. Some Government departments did extensive tests on on their own fleets in the late 70s, they tested their various trucks runnning with and without cab mounted deflectors and experimented with different running speeds. The aero aids won the day and they compared data with outside contractors.
A pickup with a truckman style cover gives more mpg and a better towing experience than one without. A high top van tows a trailer or caravan better than a standard top van and most estate cars and hatches are better than saloons. Going to slow in some windy conditions doesn't always aid fuel consumption or the driving comfort as we found with our Discoveries, to slow and the wind buffeted the caravan front, get it right and the drive was much smoother with less wind problems.
Our Windslammer brackets were bolted permanentlty to our Montego estates gutter rails when w took our children on long drives to the south of France sun. The legs of the Windslammer were fitted with quick realease bolts so we could remove the wing quickly when solo. When we left the Winslammer off for a short hop on the autoroute to another site the towing exprience was worse, gear changes went up and MPG down, When we changed to a 4 speed auto estate it would tow in top gear with the Windslammer on most of the time on motorways and autoroutes. With the Windslammer off it would constantly swap between 3rd and 4th. The manufacturer advice was to use 3 when towing a caravan, the Windslammer made a marked difference and the car ran cooler on long autoroute runs.
Windslammer needs to be set with the lower edge around 4 inches above the roof so it defelcts wind that's already rising over the roof from the windscreen, a gentle angle that deflects air flow towards the caravans roofline rather than a steep angle that causes downforce and turbulence.
Our new tow car is likely to be lower and less bulky than our Disco's and we'll be playing with our now very ancient Windslammer again.

 

[Gafferbill]

Our Windslammer brackets were bolted permanentlty to our Montego estates gutter rails when we took our children on long drives to the south of France sun.

............well that is a coincidence Gybe!!

This is my Montego 2ltr TDi + Swift with the picture taken back in 1996!
It is a fact that I could not make this tow car return less than 38mpg whilst towing during the 6years I had that outfit.
The car would return at least 50mpg solo.
I was more than happy with the economy whilst towing

Was yours a petrol version?
Incidentally I get 23mpg towing the same caravan with a Nissan Terrano 2.7TDi ........but a much improved towing experience!

 

[ProfAlGoogle]

Our Windslammer brackets were bolted permanentlty to our Montego estates gutter rails when we took our children on long drives to the south of France sun.

............well that is a coincidence Gybe!!

This is my Montego 2ltr TDi + Swift with the picture taken back in 1996!
It is a fact that I could not make this tow car return less than 38mpg whilst towing during the 6years I had that outfit.
The car would return at least 50mpg solo.
I was more than happy with the economy whilst towing

Was yours a petrol version?
Incidentally I get 23mpg towing the same caravan with a Nissan Terrano 2.7TDi ........but a much improved towing experience!

Did you do a lot of driving in fogy conditions with the Monty?

 

[Gybe]

My wifes 2 Litre HLS petrol Rust Bucket with imfamous computerised carb. Before second caravan holiday with the car Leyland garage wanted £200 to run a test program to see why overheating low water light kept coming on and quoted £400+ if it needed a new Lucas control box. Leyland parts manager told me that they never ran the computer tests, quicker to undo two screws in top of glove box with a two pence piece swap the Lucas control box and drive it around the block to see if the problem had been solved. Also advised that the lucas box was £80 plus and £35 around the corner at the Lucas parts shop. The car went though 4 Lucas control boxes and never had the expensive Leyland test. Parts manager tip saved me and others a fortune! Quoted £600+ for new replacement self leveling shocks by same Leyland dealer, about £800 fitted. Local independent parts factor chap called Boge who manufactured the "one off Exclusive Leyland" shocks. Boge supplied their Nivomat part number (fitted to a variety of cars but Leyaland had extra numbers stamped on the Nivomat) and charged £10 for over night delivery. Total £80 inc delivery. £500 + for Leyland parts numbers made them pretty exclusive. NOT!
French holiday partly spoilt by continuing electric window switch issues. Yet another Leyland tale of woe and expense, Removed the switches myself took them apart cleaned with WD40, problem cured!
Every day the Montego made strange noises. Seats, door linings and nearly everything on the dash seemed to move and squeak and groan. Lost count of the repairs and how many times the car had problems or how many times my wife gave me yet another Montego concern.
Whenever MPG took a dive the oveheating light came on next and the Lucas box needed changing. Rear tail gate and wheel arches rusted from the inside under the paint. For trade in I cut out all the rust and tig welded in fresh steel and heat treated the touch up paint and laquer. Two sales managers who inspected the car went straight to the wheel arches and tail gate looking for rust ;-) they couldn't detect the repairs and we got top trade in price. Exhaust probs, wiring, lights, door locks, leaks, tracking and much much more. I don't think we ever had a towing holiday without the car having an issue.
The Windslammer definitely made a difference on long autoroute runs.

 

[seth1]

God that picture takes me back GafferBill,good shot.Good machine too.Powered by the Perkins Prima,very very frugal.