Thread: Aerodynamics.............

Originally Posted by Tombie

Yes it does.

Stick a good gauge behind there and watch how much harder the cooling system is working to shed the thermal load.

Dougal or similar will no doubt have the engineering data, but a perforated mesh in front of an air flow is incredibly restrictive.

Hence why I smile when seeing 4wds with shade cloth over the front on boiling hot days to keep the bugs out the radiator.
Those poor vehicles are running much warmer - just the normalised gauges dont indicate the extra stress.

Yes, they run hotter, but not as hot as the ones without any radiator protection do with the radiator core stuffed with insects and grass seeds. A chaff guard is absolutely necessary for any vehicle used actually off road (i.e. in paddocks) in this country. And also essential during swarms of the Australian plague locust.

But that said, shade cloth is not suitable, as it stops too much air. Insect mesh is OK, but probably needs backing - the Series 1-2a grille makes a good support for it, and my 110 has insect mesh backed by chicken wire behind the grille.

John

Agree John..
However you aren't doing 100km/h tugging a caravan through spinifex!
Lugging along the fans are pulling the air from behind the mesh enough.

A good info on the subject

Improving Aerodynamics to Boost Fuel Economy

Originally Posted by Ancient Mariner

I don't know what this does for drag but it does seem to keep the rear window cleaner

Mariner,

Well, you've got me...I presume it's a vent for encouraging "flow through" cabin ventilation. But does it also suck in dust on dirt roads (and maybe exhaust fumes??)

If it doesn't do the sucking bit but DOES keep the rear window clean, I'm keen to learn more.

Alan

Originally Posted by Rurover

Mariner,

Well, you've got me...I presume it's a vent for encouraging "flow through" cabin ventilation. But does it also suck in dust on dirt roads (and maybe exhaust fumes??)

If it doesn't do the sucking bit but DOES keep the rear window clean, I'm keen to learn more.

Alan

I would be pretty certain it is to improve flow through of air. It should not let dust in provided vents or heater are open at all times. I doubt it woould do much for aerodynamics, although it may act as a vortex generator for the airflow over the roof.

To keep the rear window clear, twenty or thirty years ago deflectors to direct a portion of the airflow from the roof down the back of wagons used to be common as after market add-ons, and were actually designed into a few wagons. They seem to have disappeared in recent years, possibly because they do not help aerodynamics, but also because wagons no longer seem to have flat rear glass. Another reason may be that rear wiper/washers are now common, and fewer buyers regularly use dirt roads where dust rather than road grime is the problem.

I can't remember seeing one on a Landrover, but I can't imagine it improving aerodynamics (or making them much worse either).

John

Originally Posted by Rurover

Mariner,

Well, you've got me...I presume it's a vent for encouraging "flow through" cabin ventilation. But does it also suck in dust on dirt roads (and maybe exhaust fumes??)

If it doesn't do the sucking bit but DOES keep the rear window clean, I'm keen to learn more.

Alan

Sorry no connection inside to out of cabin .If you type in (aircon abit different ) in the bottom search box some info and pics if interested

AM

Originally Posted by Tombie

Agree John..
However you aren't doing 100km/h tugging a caravan through spinifex!
Lugging along the fans are pulling the air from behind the mesh enough.

No, but you may well be doing so afterwards - and spinifex is not the major problem. Most native grasses have seeds that are effective in blocking radiators, as do some exotics. Ideally, of course, you would remove the screen for on-road driving - but that is only slightly more likely to happen than cleaning the radiator after driving offroad.

And would help with the other major problem, fortunately sporadic, the Australian plague locust. Swarms of these can block the radiator in less than a kilometre, and once dried are very difficult to remove. The screen some distance in front of the radiator blocks just as rapidly, but at least it is visible, and some air gets to the radiator, without locusts, around the edges, especially if it is on the bullbar.

John

Locusts.. Great aren't they!
Driven in a few plagues now...
Air intake was a larger issue interestingly.
Just hosed the buggers out of grill but the airbox was almost full...