Wind Deflector and solar panels.

The actual aerodynamic benefit would be very small, and as far as mounting them facing forward, well you have answered that. One stone chip basically destroys the panel, so it's not something I would do.

Mark,

The concerns I would have from the perspective of mounting them on a front facing angled wind deflector are as follows.
Firstly damage to them by rocks or whatever and I guess that depends on the size of the rock and how resilient you reckon the panels are. This of course is not totally negated by having them mounted flat on the rack, but in my opinion, reduced.
Secondly the fact that flat mounted non movable panels are more likely to get sun exposure for a greater amount of daylight time than angled at any fixed orientation without moving the vehicle.

As far as how effective a wind deflector is, I would imagine the trucking industry wouldn't bother with making something the size of a small house as streamlined as possible including deflectors to prevent wind getting behind the cab and impacting the trailer if some measurable gains were not forthcoming.
How much would it cost to fabricate a simple deflector from plywood or similar, attach it to your roof rack, and do a trial run or two? If the effect is not what you desire don't bother. My feeling is that there will be some benefit. How much is up to you.

Cheers
Pop

I used solar panels but not forward facing. Can't see the point in that. Predominantly the sun is in the sky so above is best. Unless the flexible or hard panels are definitely pointed to the sun, then most of the time, nearly always, they will produce very little.
You don''t mention the size or area of the proposed deflector but I use two hard solar panels on the roof of a Dmax and made a wind deflector/fairing out of part of a Hyundai rear bumper plastic. It DOES Reduce wind drag and noise because it is cut to the roof shape and the curve of the plastic runs the air up and over the panels. Works well.

Kimberley have a forward facing solar panel on the top of the front box lid of their Kampers (faces like a wind deflector would), I've had fist size rocks spitting out the back of my 4wd up near Kingfisher Camp in the NT, peppered the camper with stone chips out West around Birdsville, etc etc, and still no sign of the solar panel sustaining any damage. Solar panels aren't as flimsy as people think they are....yes they can be smashed, but I've not had a problem with my camper or the solar panel I had mounted on my 4wd as a wind deflector like you want to do either. I mounted my panel to help deflect the wind off of the storage box I had mounted on the roofrack for a 6 week trip, i'd like to think it made a differance to fuel economy, but i doubt it was huge

From the replies I'm thinking I'm better off forgetting about the solar panels there and perhaps focussing on a streamlined wind deflector. Thanks for the feedback.

Cheers,

Mark

Apart from any possible wind flow advantage, a deflector will keep bugs from squishing on other items stored on the rack.
Paul

Silkwood,

It has always been my understanding and experience that a wind deflector does very little to economy.
It has however a big advantage advantage of reducing wind noise inside the cabin, (specially if the deflector comes down as low and minimised the gap between to the roof of the car).

Cheers,

I have had a 90 Watt Solar Panel mounted on my roof rack for years. Fraser Island, Cape York, Kimberely, Canning Stock Route etc. All driven to from Melbourne so lots of Road and Off-Road kilometres. No issues or stone chips etc. I wash it when I wash the car or when I am in the servo washing my windscreen.

Hi Silkwood, had a deflector on my hilux for 12 years that angles up to the height of the ally canopy. Fist thing I put on a new car will be the same plus a panel to add to the two that will be flat on top. Keeps the bugs off as well.
cheers Graeme.