Would removing the radio antenna and rear wiper on the Prius improve its aerodynamics at say 75mph? Or would it have so negligible an effect that it really wouldn't matter?

I ask simply because I was discussing the somewhat silly shape of the Prius that compromises looks for aerodynamics, and it occurred to me the antenna and rear wiper may have been after thoughts given the rest of the design.

Does blocking off the front grill in cold weather improve aerodynamics? We don't really get cold weather here, but I'm curious.

Prius 2006, bought September 14:

Perhaps. I've noted some discussion on other boards that have thought of replacing the antenna with a more aerodynamic sale style. With the rear wiper you'd have some explaining to so about the knob sticking out of the back and it may be illegal in some states.

I kinda like the looks of the Prius. Its distinctive as well as functional. It's not entirely unique as the Sienna looks eerily similar head on.

I'm not familiar with the Prius rear wiper, but perhaps just changing out the stock rear wiper blade with a more aerodynamic blade would suit your needs (and be safer, and legal).

http://www.valeowipersusa.com/index.asp?pgid=19

I run Valeo Ultimate wiper blades on my Ford Escape Hybrid. I didn't change to them for aerodynamics ('cuz I'm driving an Escape Hybrid, afterall... not a sleek-profiled Insight or Prius), but they do boast being better aerodynamically than most...and they sure look it, and grab the windshield even at hwy. speeds better than my stock blades did.

- Shannon (Geeky, Wild Texan)

Why would no wiper on the rear be illegal?

I don't think a rear wiper is a requirement in any state.

Good point, though I think there's probably a reason there are rear wipers as standard equipment on certain types of modern vehicles (Ford Escape, and most other SUVs, etc.) Maybe not... maybe it's just one of those accessories manufacturers have just started putting on as a matter of course, but I know with my Ford Escape Hybrid the lack of a rear windshield wiper would result in reduced visibility in the rain or wet weather, because the draft of the vehicle funnels ALL road gunk and water to the rear window, where it stays due to the wind currents around the vehicle when underway.

/shrug

The pitch of the rear window on most sedans, and the greater aerodynamic profile of those vehicles as a whole, tends to prevent the crusting/caking/fogging up of the rear window that occurs so easily on SUVs and such. The Prius has a larger and rather irregularly (compared to standard sedans) angled rear window, so it probably has the same issue as my FEH in wet weather, hence the wiper.

ADDED LATER:
Just Googled it because this made me curious. Here's what my state's (TX) motor vehicle code has to say about rear windshield wipers:
Typical legalese, but the note at the end sounds like it doesn't matter (at least in TX) what you have or don't have in the way of wipers on the rear window, regardless of what was "stock" on the vehicle. Maybe others read that differently? I love how it seems a vehicle in TX can be "presented for inspection without a windshield"... that would explain some of the drivers on our roadways

- Shannon (Geeky, Wild Texan)

Gotta love Texas.

I would be suprised if most states did not read about the same way. The reason the windshield is not required is that there are some vehicle that don't have them. Think some low slung sports cars. Also you could drive a jeep with the windshield folded. I don't really recomend it since it would be really windy and you would get your protien from all the bugs.

At 75mph you won't see much if any improvement in aerodynamics for increased mpg. The rear wiper is within the vehicles laminar airflow. But removing the antenna and rear wiper probably would make a difference at say 200mph but not at 75mph.

hahaha, Very nice - well I guess I better get those removed then, I plan on doing 200mph tonight, just like every night.

Seriously though thanks for the technical look at it Resist, that's essentially what I was wondering - if the 2 parts even make an impact on aerodynamics with the way air flows at highway speeds. Apparently it's negligible afterall.

So - what about when people block off the front grill in the cold? That must improve aerodynamics at any speed, no?

Prius 2006, bought September 14:

Yeah but then again the cold has a way of making it a push because of the other problems that come with cold. Higher liquid viscosity of coolant and oil which makes the engine work harder. The engine also has to work longer to maintain operating temperature. Both for the operator and the mechanical parts like the traction battery and catalytic converter.

I actually use a block heater to help with those cold mornings and I kind of like the instant heat.

Actually no. Air that enters the front grill also exits the engine bay area. So by blocking the front grill the vehicle hits a wall of air instead of slicing through it. Thus reducing mileage gains.