Tuft testing a C-Max

[fbov]

Well my highway testing continues to confound and amaze me!

 

This time, it's snow tires all around and aero wheel covers on the back. (Lost a front, but that's another post). All the prior data is still shown, but with open markers and dotted trend lines to make the new data more evident.

 

Once again, no effect given the noise. The snow tire data falls right on top of the prior data, with the trendline nearly coinciding with the prior test! Time to get off the highway... of course, that will confound VGs with the snows, as time precluded testing VGs on back roads. In theory, rolling resistance is a greater hit at lower speeds as rolling time lengthens, so given parity at highway speeds, perhaps I'll see a difference...

 

Not complaining, mind you!!! Given what some others have reported for other brands of snow tires, this makes me very happy choosing X-Ice 3's.

 

Have fun,

Frank

[Recumpence]

Frank,

 

Here is a picture I took of my car today. We had powder snow last night and, after driving for a while, I noticed a few aerodynamic details that were worth noting. The clearest one was this shot I took. You can see by the snow line the exact point of air detachment on the upper portion of the rear fender before the rear window.

 

I hope this information is useful to you Frank (and anyone else who is curious).

 

Matt

 

 

[hybridbear]

In my trips in the C-Max bringing my parents to and from the airport, etc recently I noticed how hard it is to keep the back window clear on slushy roads. The spray from the tires seems to get sucked up onto the back window by the airflow. I find that I'm often washing the rear window to see out of it. The back up camera also becomes so dirty that it is worthless for backing up because you can't see anything with it.

 

I also have noticed that when driving in hybrid mode the exhaust gets sucked up by the air flow and I see all the white exhaust up high behind the back window. In our FFH I'll see a tiny amount of the white exhaust being lifted up beyond the level of the trunk at highway speeds but nothing like the turbulence behind the C-Max.

 

Have others noticed the same thing?

[Recumpence]

Yup, I noticed the same thing/s.

 

I am building a diffuser soon as well as a Kammback. I am hopeful a cleaner tail end of the car will be a welcome side benefit.

 

Matt

[Recumpence]

I figured I would chime in and let you guys know I have been doing much "Snow-rodynamic" testing since we have had so much powder snow lately and my snow paterns on my car definately agree with the tuft testing. The air flow is clean off the roof, yet it is very turbulent off the sides of the car and sides of the rear window. The air detaches right at the side edges of the rear window continuing down the side of the car to the rear portion of the rear wheelwell.

 

I plan on making my Kammback design based on these findings.

 

Matt

[ptjones]

I figured I would chime in and let you guys know I have been doing much "Snow-rodynamic" testing since we have had so much powder snow lately and my snow paterns on my car definately agree with the tuft testing. The air flow is clean off the roof, yet it is very turbulent off the sides of the car and sides of the rear window. The air detaches right at the side edges of the rear window continuing down the side of the car to the rear portion of the rear wheelwell.

 

I plan on making my Kammback design based on these findings.

 

Matt

I inadvertently got similar results when a piece of magnetic tape came off between the hatch and turn signal light and ended up on bumper instead of blowing away. :) 

 

Paul 

[hybridbear]

What causes the dust/snow/etc to all stick to the back of the car? The C-Max back hatch gets extremely dirty, so does the back hatch of my wife's Prius. The FFH isn't as bad, but the trunk area also gets extremely dirty. What part of the aerodynamics causes this? Is it the turbulence at the back?

 

Another FFH owner recently noticed this:

 

To give some balance to the weather on this forum, it's warm and dry here in SoCal.  We're in a dad-gummed drought while half of you are freezing to death.

I've owned this FFH for over a year and after spending 30 years in a big city fire department I learned to keep my tools clean, so I wash it a lot.

Looks better too.

 

The back of the car always seemed to have a lot of dust buildup from the aerodynamic shape of the car creating a small vacuum in the back of the car (I don't have the trunk spoiler).

I'd like to discuss the OEM quality splash guards and the difference they seem to make with the dust buildup on the back of the car.

A few months ago I purchased and installed the OEM Splash Guards, front and rear.  They really do work well keeping the wheel splash debris off the sides of the car.

I got used to the funky look real fast too, now I like it.

But the unusual after affect of installing them is the back of the car stays a lot cleaner from road dust buildup.

I wonder if the guards create a turbulence under and around the bottom of the car or wheels that disrupts the normal vacuum at the back.

 

I notice this because every time the trunk opens I used to put a dusty fingerprint on the paint, not so much now.

With the under-body streamlining I think the splash guards now work to defeat this rear dusting effect, it's a positive thing for me.

Thoughts?

http://fordfusionhybridforum.com/topic/8229-splash-guards-mudflaps-warm-weather-and-dust/

 

How would the mudflaps be changing the air flow to result in less dirt adhering itself to the trunk lid? I might look at getting some if they'll help keep the trunk cleaner. Perhaps they'd also have that impact on the C-Max. I wish I had a better understanding of aerodynamics to know, but I'm glad that there are C-Max owners who do since I don't. Thanks!!

[ptjones]

I'm working on it, but I haven't figured out which camcorder to buy. :)

 

Paul

[fbov]

From what I can gather, a dirty tailgate is the penalty for good aerodynamics. Let's review some of what we know.

- Bernouilli's law can be paraphrased to say that air pressure on a surface is inversely related to the speed of that air across the surface. Areas of high speed air flow will generate a vacuum.

- When dealing with tailgate, any vacuum resulting from the air flow will  be felt as drag.

- Dust particles borne on the wind will land and stay put only in areas of low air flow. Otherwise, they'd be knocked off.

 

The logical conclusion is that a car designed to minimize air flow-related drag on the back of the car will likely get very dirty.

 

Looking at the tuft test stills, you see a very sharp change in air flow at the edge of the rear window. Air flow on the C-pillar is attached, but that on the window is both low speed and only slightly turbulent, and it's at right-angles to the C-pillar flow - a clean break. The rear window air flow is consistent with weak trailing vortices coming off the C-pillar- the right air flow direction with not a lot of speed - so dirt builds up. 

 

I've got some pic to show these effects, but need a cable...

 

HAVe fun,

Frank

[hybridbear]

From what I can gather, a dirty tailgate is the penalty for good aerodynamics. Let's review some of what we know.

- Bernouilli's law can be paraphrased to say that air pressure on a surface is inversely related to the speed of that air across the surface. Areas of high speed air flow will generate a vacuum.

- When dealing with tailgate, any vacuum resulting from the air flow will  be felt as drag.

- Dust particles borne on the wind will land and stay put only in areas of low air flow. Otherwise, they'd be knocked off.

 

The logical conclusion is that a car designed to minimize air flow-related drag on the back of the car will likely get very dirty.

 

Looking at the tuft test stills, you see a very sharp change in air flow at the edge of the rear window. Air flow on the C-pillar is attached, but that on the window is both low speed and only slightly turbulent, and it's at right-angles to the C-pillar flow - a clean break. The rear window air flow is consistent with weak trailing vortices coming off the C-pillar- the right air flow direction with not a lot of speed - so dirt builds up. 

 

I've got some pic to show these effects, but need a cable...

 

HAVe fun,

Frank

Frank - this makes sense. This explains why the Prius (a car designed to be very aerodynamic) is even worse than our FFH at having dirt adhere to the tail of the car. So basically, the FFH owner who added mudflaps changed the way the air flows around the wheels and the tail of the car and thus created more turbulence/drag?

[C-MaxSea]

Speaking of tuft testing, laminar flow …………………….

 

Is this where we are heading, a redesigned rear quarter panel some day for the C-Max?

 

 

Before & After Priiiii;  & then there is the bug eyed Leaf 'solution':

Edited January 25, 2014 by C-MaxSea

[mtb9153]

I can see them going to the 3rd picture someday

[mtb9153]

I'm working on it, but I haven't figured out which camcorder to buy. :)

 

Paul

Paul if I was going to buy another camera...which I'm not.  I'd get the Canon VIXIA HF G30 Full HD Camcorder from B&H Video & Photo in Brooklyn NY.  I think the Canon optics is superior to any one else, even Sony. I've always liked the lens much better on my 4 year old Canon XHA1 than my one month old Sony.  Carl Zeiss optics is just a name and not worth the $$$$.  I think you'd have to look REAL hard to find better prices and service from anywhere else but B&H.  The only thing which bugs me about B&H is they are a Jewish business and it always seems that when I want to order something they are closed for one of their many observances.  I'm not slamming the Jewish faith, just a beef I need to live with so no Hate mail everyone please.  I'm equal opportunity religious believer.  :camera: :thumbsup:

Edited January 25, 2014 by mtb9153

[mtb9153]

From what I can gather, a dirty tailgate is the penalty for good aerodynamics. Let's review some of what we know.

- Bernouilli's law can be paraphrased to say that air pressure on a surface is inversely related to the speed of that air across the surface. Areas of high speed air flow will generate a vacuum.

- When dealing with tailgate, any vacuum resulting from the air flow will  be felt as drag.

- Dust particles borne on the wind will land and stay put only in areas of low air flow. Otherwise, they'd be knocked off.

 

The logical conclusion is that a car designed to minimize air flow-related drag on the back of the car will likely get very dirty.

 

Looking at the tuft test stills, you see a very sharp change in air flow at the edge of the rear window. Air flow on the C-pillar is attached, but that on the window is both low speed and only slightly turbulent, and it's at right-angles to the C-pillar flow - a clean break. The rear window air flow is consistent with weak trailing vortices coming off the C-pillar- the right air flow direction with not a lot of speed - so dirt builds up. 

 

I've got some pic to show these effects, but need a cable...

 

HAVe fun,

Frank

Frank need a cable?  Go to Radio Shack, there must be one near you in NY.  For that matter go to B&H Superstore in Brooklyn if it is anywhere close to your town.  They are a city block long, massive store from what I've seen on their website.

[ptjones]

Paul if I was going to buy another camera...which I'm not.  I'd get the Canon VIXIA HF G30 Full HD Camcorder from B&H Video & Photo in Brooklyn NY.  I think the Canon optics is superior to any one else, even Sony. I've always liked the lens much better on my 4 year old Canon XHA1 than my one month old Sony.  Carl Zeiss optics is just a name and not worth the $$$$.  I think you'd have to look REAL hard to find better prices and service from anywhere else but B&H.  The only thing which bugs me about B&H is they are a Jewish business and it always seems that when I want to order something they are closed for one of their many observances.  I'm not slamming the Jewish faith, just a beef I need to live with so no Hate mail everyone please.  I'm equal opportunity religious believer.  :camera: :thumbsup:

Like camcorder's spec. but i won't be able to justify it. I will probably stay in the $400 range. O well :)  Check your PM

 

Paul

[mtb9153]

Like camcorder's spec. but i won't be able to justify it. I will probably stay in the $400 range. O well :)  Check your PM

 

Paul

Here's another nice palm size camcorder with great specs and it comes with a neat clear acrylic housing for waterproof shots up to 16ft..  B&H priced at $398 and available on pre-order since it is new and wasn't available when I got my hdr-cx210 Sony HDR-AS100VR POV Action Cam + Live-View Remote Bundle  

[fbov]

Frank need a cable? ...

Thanks, but I have the cable. It's just in the car... and I'm not remembering to bring it in with me! It's just a software problem.

Edited January 27, 2014 by fbov

[RaPieR]

It's not a C-Max but interesting video I just saw on the Fusion.

 

http://www.youtube.com/watch?v=7o8xvuzyowU

 

Wonder if they have a similar video for the C-Max somewhere.

 

Found a snippet for the 5DR Focus which has a closer body style to the C-Max

 

http://www.youtube.com/watch?v=xjqINNH8Rzg

Edited January 29, 2014 by RaPieR

[fbov]

Erect video snippet now available here.

 

This is a 20-sec. clip of the better of the two videos in 1080p so I trust you can see things.

 

HAve fun,

Frank

[ptjones]

Having problems viewing video in that tuffs are moving to fast and lack of contrast. I need to figure out how to slow motion it. Nice try, I have orange tuffs made but haven't got camera yet. :) 

 

Paul

[fbov]

You're missing the forest for the trees. The only thing you NEED to see is the tape holding the tuft.

 

If you see the tuft, it's laminar and he tuft tells you direction. 

Sides above the wheel wells, entire fishbowl back to the hatch, and a good portion of the rear glass (note divergence away from centerline).

 

If you can't see the tuft, it's turbulent and there is no direction.

Between the tail lights and below you can't see tufts. You also can't see them at the crease below the rear glass, where mtb's spoiler sits.

 

Then there's everything inbetween...

- Wheel well turbulence occurs in a region of high flow, so you see blurry tufts.

- Below the tail lights, you can see a transition going around the corner from laminar to turbulent

- While the upper rear glass has stable, slow flow, the lower portion picks up some of the turbulence between the tail lights

 

Slowing it down to 1/4 speed (i.e. repeat each frame 4x) does let you see the tufts in turbulent regions... I'm surprised how well they freeze! (Not bad for a $70 camera... )

 

What do you see now?

 

HAve fun,

Frank, who wishes he'd found Movie Maker sooner...

Edited March 6, 2014 by fbov

[C-MaxSea]

:future:  I still see Prius flanks in our future.  (glad I have a 2013 with beautiful hips)  Nick

[fbov]

My Fathers Day gift was a new spoiler, or should I say getting to fabricate one....

The idea was to use aluminum angle bar stock and find a flat spot where it would mount. When I finally crawled underneath, and realized I could use the front panel as a template, I knew I was onto something.

 

I started with  2" x 1/16" x 8' aluminum bar stock from Home Depot, a jigsaw with metal blade, and a pair of pliers. And a 5/16" Allen bit in place of the right Torx bit. First, remove the plastic panel between front lip and crossmember

- there are 7 screws (4 long from the tire spoiler, 3 short from the crossmember)

- there are 6 plastic plugs (pull center out to release the plug)

 

Then, cut out the bits on the bar stock

- cut a "V" in each side of the angle stock 36" apart, so you can bend it.

- use the plastic panel as a template for several features

relief for the panel under the engine (cut outs in plastic piece)

tangs that you will bend back into the two slots in the plastic piece

tangs with slots that will go under the three screws

- the tangs under the screws need a compound bend to follow the contour, up as little, then back down

- the tangs in the slots are very helpful aligning things, so you can locate attachment features

- the relief areas I just cut a slot and bent the section until it broke.

- watch length at the ends, and be sure to curve the top to match the contour of the plastic cover at the ends.

 

No idea if it works, but give me a few weeks. I've been running ~55mpg on the way to work lately, and this should show better at high speed, but we'll see.

 

HAve fun,

Frank

[Marc Smith]

bene reading this post.  and i was intruiged...  on my prius th eclear glass portion of the tailgate stayed clear, while the vertical glass  stayed dirty,  same coudl be said for my HHR  the HHR has a similar rear shape as our C-max.  flat back.  while the prius  is a bit more slippery.

 

do you guys ever remmebr back in the 80's 90's  the rear wings they had on wagons...  I think these were designed to move air flow over the back to help keep the glass clear.  Might it have also helped to divert airflow over the back to reduce drag...

[kostby]

That wing helped a little since there was no rear wiper, but drive on a dry dusty country gravel road, and it was pretty worthless. I don't think I drove one enough in the rain to remember if it helped or not. My father-in-law had a 1988 Oldsmobile Custom Cruiser much like that one, in burgundy. It was like driving a Sherman tank, except it wasn't nearly as noisy, and you didn't have to stand up to see out… (Yes, I actually rode in a WW II-era Sherman when I was about 8 years old!) 

 

Like adding roof rack, that downturned edge probably adds enough drag to hurt mpgs a couple of tenths on a modern hybrid.

Ebay is full of the those "JDM" wings you see the kids add… http://www.ebay.com/sch/Spoilers-Wings-/33638/i.html

 

Wings probably didn't affect gas mileage significantly in 1988, because the car was already boxy and weighed two and a half tons, with a 140hp 307 4bbl and lock-up torque converter. It was rated at 15 city/22 highway, 18 combined. Who knows, maybe the rear wing actually helped handling at speeds above 140mph  ;)

 

My 2003 Vibe still has the factory-standard roof rack and crossbars, removable only with a major disassembly of the rack and some very-breakable plastic pieces and fasteners. I moved the bars rearward as far as possible, hoping to get them out of the wind because the roof peaks over the B-pillar and slopes down before the C-pillar. In 2005 the crossbars were made an extra-cost option, and I notice on Fuelly that the 05's seem to get slightly better mileage, but it could be because of a different grille design as well.

Edited June 16, 2014 by kostby