AirFlow BulletTruck Project (aerodynamic, modified Class 8 transport doubles MPG)

[Shepherd777]

Originally Posted by ECONORAM

Maybe on the next model, an adjustable nose piece to raise and lower might be beneficial?

Absolutely, ECONORAM.

We already had a dynamic front in mind for the new truck. Up when slow, down & low when cruising.

[Shepherd777]

Originally Posted by rajadaja

Do you have any information on how much additional weight has been added? Do you have any special strategies for when there is no load? Do you also have habits/behaviors that help you increase your mileage?

Weight was prolly a push, as we removed as much as we added. But we never did do an exact former and after certified weights at a weigh station.

No special techniques when empty other then to be careful in slippery conditions and not use the engine brake. That would possibly induce a jack-knife.

Habits and Behaviors? Well, yeah. Cruise at 55 mph, operate the diesel engine between 1100-1250 rpm's exclusively, progressive shift, never idle, use a high percentage of cruise control, etc., etc., etc.

[elhigh]

One wonders what you could achieve, packaging-wise, by splitting up radiator duty. I understand the Bugatti Veyron, with its enormous heat load from that multiply-turbocharged engine, has 10 separate radiators - three of them are for the engine.

I think the reason there is that in order to keep the aero reasonable and not have a gigantic Volvo barn door nose, they have to be made smaller to tuck into less-frontal positions, hopefully ones that are something close to aerodynamically neutral in their effect on the vehicle's total drag.

So, is that an option? Could you break up the rig's radiator duties between several smaller units, pull cooling air in around the front wheels and dump it through the gap in front of the trailer? No testing, I just have a hunch that would be the most advantageous place to do it. Of course this would require a gigantic amount of high-volume ducting.

[ECONORAM]

elhigh, I was literally thinking the same thing. Smaller units could make packing the whole front end easier.

[Shepherd777]

Originally Posted by elhigh

One wonders what you could achieve, packaging-wise, by splitting up radiator duty. I understand the Bugatti Veyron, with its enormous heat load from that multiply-turbocharged engine, has 10 separate radiators - three of them are for the engine.

I think the reason there is that in order to keep the aero reasonable and not have a gigantic Volvo barn door nose, they have to be made smaller to tuck into less-frontal positions, hopefully ones that are something close to aerodynamically neutral in their effect on the vehicle's total drag.

So, is that an option? Could you break up the rig's radiator duties between several smaller units, pull cooling air in around the front wheels and dump it through the gap in front of the trailer? No testing, I just have a hunch that would be the most advantageous place to do it. Of course this would require a gigantic amount of high-volume ducting.

Originally Posted by ECONORAM

elhigh, I was literally thinking the same thing. Smaller units could make packing the whole front end easier.

Gentlemen, great minds think alike. We actually had a split radiator system design in one of our first incarnations of the BulletTruck cooling system over 4 years ago.

We initially obtained two brand new Kenworth T300 (I believe that was the model) radiators from one of our sponsors. These radiators were physically smaller, and were wider than they were taller. The exact opposite configuration of the OEM radiator, which is taller than wider. We were going to mount the two smaller radiators in a side-by-side shallow "V" configuration. Cummins had previously confirmed that the OEM water pump would work perfectly in a split system.

But we felt that the mounting brackets and the shroud ducting system for two radiators in this configuration would have been a nightmare. So we just built custom brackets and supports for the OEM radiator and mounted a new one of those below and in front of the frame. This is opposed to the traditional "radiator on top of the most-forward frame crossmember" configuration that has been used on trucks for the past 100 years or more. This was the very first instance of mounting the cooling system package forward of the frame and lower, AFAIK.

10 months ago, Daimler AG/Freightliner debuted their Freightliner Revolution to the public and I was there in person at that event. They use somewhat of a split cooling system, segregating the A/C condenser from the radiator and charge air cooler, claiming this configuration "increases airflow and reduces pre-heating of the charge air cooler and radiator." They also use a smaller custom radiator than their marquee OTR truck. And quite coincidentally, or not, they mount it forward of the frame and lower than the traditional location. Gee, I guess they could have learned something, after visiting my web site so many times in the past 4 years.....

[bikeprof]

Mr Shepperd.., GREAT action of yours! Getting your aerodynamic improvements into actuality and getting them to be of use.

I had my trucks, the last one:
2000 F. Century raised flat top,
500 Cummings red top,
10sp over w/22.5's(NO cheena made tires!),
and running spread flatbed and usually 75,000 lbs.

Made average of 8.2(~62-64MPH) +/- MPG average(per MY calculations), did very little aero MODS but anything helps!
Broke into the 10's THREE times and all were loaded miles, other drivers listened to me like if I was telling them a science fiction story !?!?!

MORE POWER to you in this endeavor!
Keep the wind behind you and the Diesel off the highway.
Would LOVE to see ya when you come by Phoenix, let us know!

[stillsearching]

Surprised you retired the truck. Did the economics not work out from something unexpected, or do you just have a much better project in mind? It seems like such a winner would still be in operation is all...

For your "next project" concerning IP protection and all that, consider seriously trade dress protection... patenting is difficult (and expensive, and it's not like nobody has never designed an aero truck before), "first to market" without protection still gets ripped off by the big boys within months in most markets, but trade dress lets you protect a given shape and something too close to it is considered in violation. It's intended to prevent "confusingly similar" shapes, examples might be the iconic shape of certain liquor bottles, or shampoos which might be associated with one brand or another, i'm not positive but I thought the shapes of cars tend to often have this protection hence why they have to be licensed to appear in video games and such now.

Did you ever have a realtime MPG figure of running at 40mph for comparison, or 70mph with the same mods? Since you have the only example of an aeromodded semi that I know of i'm curious whether it follows the general formulas used for smaller trucks and cars.

[Shepherd777]

Originally Posted by stillsearching

Surprised you retired the truck. Did the economics not work out from something unexpected, or do you just have a much better project in mind? It seems like such a winner would still be in operation is all...

Hi stillsearching -

The economics of the BulletTruck worked out better than I had ever imagined. We did not have a rear-of-trailer treatment (boat-tail) and we still had 2 "live" differentials, and we still averaged 13.4 mpg hauling freight during that big 8003 mile trip, that my dog and I did last summer. On that one trip alone, we saved over $2500 in fuel. Here's the math: 8003 divided by 6.5 mpg = 1231 gallons x $4.00 per gallon = $4925. 8003 divided by 13.4 mpg = 597 gallons x $4.00 per gallon = $2389 fuel burn. $4925 minus $2389 = $2536 fuel saved, again on only that one trip. And I felt that we could have easily averaged 15 mpg or possibly a little more, with a "meatball" removed from the rear differential, and that boat-tail. Hell, everyone here at the forum knows exactly how important the rear of the vehicle treatment is.

But yes, the real reason that truck was retired, is that we do have a better project in mind. That being our next-generation, "scratch-built" rig. That, and the "I hate the trucking" part. I just like to build them. Not drive them for weeks at a time.

Originally Posted by stillsearching

For your "next project" concerning IP protection and all that, consider seriously trade dress protection... patenting is difficult (and expensive, and it's not like nobody has never designed an aero truck before), "first to market" without protection still gets ripped off by the big boys within months in most markets, but trade dress lets you protect a given shape and something too close to it is considered in violation. It's intended to prevent "confusingly similar" shapes, examples might be the iconic shape of certain liquor bottles, or shampoos which might be associated with one brand or another, i'm not positive but I thought the shapes of cars tend to often have this protection hence why they have to be licensed to appear in video games and such now.

Thanks for the tip! I have never heard of that "trade dress protection". I will have to research that.

Originally Posted by stillsearching

Did you ever have a realtime MPG figure of running at 40mph for comparison, or 70mph with the same mods? Since you have the only example of an aeromodded semi that I know of i'm curious whether it follows the general formulas used for smaller trucks and cars.

Nope. We only ran that truck at 55 mph. Except downhill, where I let it run-out to 70-75 mph, depending on the speed limit. I would guess the results would be the same as smaller trucks and cars. Physics is physics.

[Flakbadger]

Originally Posted by Shepherd777

Physics is physics.

I think I remember reading someone's quote from Hucho's book, saying that flow attachment doesn't change from 5-200 MPH, it's only once you get REALLY moving that it changes.

[Xist]

Weeks at a time? I do not like driving for minutes at a time...