Kamm back speed at which it starts to work?

[Christ]

OP - sorry about that. I have no idea when a Kamm is most effective, but I know the theory and practice of it's application, based on information attained from this site and other sources. None of which are personal experience.

[Christ]

General population - Braingle: 'Tailgate Flap' Brain Teaser

[mobilerik]

Originally Posted by Christ

Person w/ the Toy PreRunner - If you have stake pockets in your rig:

1. Put tight fitting boards in them, at least as tall as the top of your cab.
2. Get a chalk line, and learn to calculate the angle of a scalene triangle based on it's right angle size. (Or get a protractor)
3. Tap a nail into the board at the cab-line on the front,
4. Tap a nail into the rear board at a level that creates a 13* angle from the front to the rear
5. Snap your chalk line between those two points, and cut them off on that angle
6. Same on other side
7. Frame off the 4 or 6 boards in your stake pockets so they're all attached to each other, and won't move around
8. Get a canvas tarp, or something waterproof that doesn't look too "redneck" (if you care about looks)
9. Attach it to the frame, starting at the top and cleanly folding it into itself to create the taper down to the tailgate, stapling/brad nailing it in place as you go
10. Test
11. Record results

I suppose you mean me? You can call me "Rik", btw. It sounds like you're describing either a very high sloping tonneau cover or the back of an aeroshell. No I don't have stake pockets. You can see my solution at the end of my build thread: http://ecomodder.com/forum/showthrea...nner-6342.html I'll be building a sturdy version tonight.

Originally Posted by Christ

You should see some kind of drag improvement by doing this, as it effectively creates a boat-tail of your bed, one of the easiest things to do to a truck.

You will, however, notice less winter (snow and ice) traction at speed,

Good thing I live in San Diego, eh?

In my build thread, you can see some "teardrop analysis" and discussion of my options re: a Kamm-style chopped boat tail to work for my shortbed.

[Christ]

K "Rik", yeah, I meant a shell :P Good work on your truck though.. your avatar image doesn't show it, so I didn't know about it.

EDIT - I guess it does... mibad, I just saw a plain ole' Toy in that image.. I guess the mind really does see what it wants.

[CobraBall]

Originally Posted by aerohead

The Kammback citing may have been used in the context of separation-free flow up to the point where the car body was chopped off.And with Cd0.37,the K-cars were remarkably "cleaner" than their contemporaries.And yes,the K-cars did have cross-wind stability problems.The up-shot is that Dr.Morrelli solved that one back in the 1980s,so we're better protected from those challenges.

If the K-car you are talking about is the 1978 Pontiac Firebird Wagon (see attachment), IMHO it is a "truncated hatchback" which is different from a "Kamm Back". Examples of a "truncated hatchback" would be AMC Gremlin & Lancia Y10. In the 60's and 70's it was common station wagon to have a roll-down back window built into the back wagon door. A station wagon is nothing more than a "truncated 4 door sedan." With the rear window cracked open carbon monoxide poisoning from the exhaust was a threat due to the low pressure at the rear.

Drag Racer Don Schumacher's Vega Station Wagon called the "Wonder Wagon" did not last very long. The truncated 2-door had a bad reputation of poor handling near the finish line. Don kept the name and switched to a coupe.

0.37CD is the same as the Volkswagen Tiguan (SUV). Always thought SUV, aero & CD in the same sentence was an oxymoron.

A true Kamm Back has flowing tapered lines and then sharply truncate the end. The best racing example of a Kamm Back may be the Shelby Cobra Daytona Coupe (below). Others examples are the 1970-86 Citroen GS, 1984-91 Honda CRX, 1992-98 Mazda MX-3, Insight, & Prius.

Professor Wunibald Kamm, head of the Automotive Research Institute at the Stuttgart Technical College developed his Kamm Back theory to shorten the length of a tear-drop-rear-end design and still have a good aero/CD.

The Fastest Indian was a little Hollywood but Burt took his Indian Streamliner Motorcycle to Bonneville 12 years in a row. The movie had to condense the 12 years into 90 minutes. Burt is one of the true LEGENDS/ICONS of high speed racing.

IMHO if the Kamm Back was the answer to an aero rear end design, then high speed bicycle and gravity racers would use a Kamm back in lieu of a tear-drop design.

[MetroMPG]

Originally Posted by CobraBall

If the K-car you are talking about is the 1978 Pontiac Firebird Wagon, IMHO it is a "truncated hatchback" which is different from a "Kamm Back".

This is Kamm's K car:

0.37CD is the same as the Volkswagen Tiguan (SUV).

That may be, but the Tiguan is a modern, detail-optimized shape. Compare Kamm's work to contemporary vehicles and his accomplishment is more evident. Give him a Tiguan, and he'd improve its rear design and lower its Cd too.

IMHO if the Kamm Back was the answer to an aero rear end design, then high speed bicycle and gravity racers would use a Kamm back in lieu of a tear-drop design.

Nobody has suggested that a complete tear drop shape isn't more efficient.

The Kamm back is the answer to good aero design in production vehicles where (a) it's not practical to extend the vehicle's lines to the ultimate teardrop end, and/or (b) where consumers would likely reject a full or near-full tear drop as too radical. HPV's, gravity racers and solar cars don't face either of those constraints.

[CobraBall]

MetroMPG,

Thanks for the picture of Dr. K's K-car. My mistake.

After the 1934 Chrysler Airflow was introduced, the Auto Design Institute retired the "THE BUTT-UGLIEST " trophy to permanently to the Chrysler Design Studio.

[Christ]

First time I heard/read K-car: I thought of the Plymouth Relient. Not exactly an aero wonder, if yaknowuddimeen.