Engineering Trailer Aerodynamic Device

Howdy,

I'm an aeronautical engineer working for a military jet engine manufacture designing a rear end aerodynamic device to reduce drag on tractor trailers (you may have heard of this referred to as a 'boat tail'). From a business perspective it makes a lot of sense to reduce fuel consumption as it's a primary business expense. I know alot of other people realize this and have developed literally a million solutions for this problem. Alot of them suck; yet some are successful. The trailer skirts have really taken off, and cabs have been more or less perfected.

Now from an engineering perspective & a business standpoint it doesn't really make sense for an entrepreneur such as myself to really take a huge financial risk for a 5% improvement in fuel consumption (which is what alot of people are going for). The back end of the trailer has the most room for improvement (approximately 40% of drag on a modern truck) so thats what im shooting for. A few other companies have realized this and have developed solutions that attack this problem. Yet from an engineering perspective they all suck. Some only reduce drag by 10% and others make unloading difficult.

My goal, one I have been working on for the last year and a half, has been to create a device that is unrestrictive to a driver but also gets 25% improvement on drag. So far my homebuilt supercomputer suggests that those numbers of drag improvement are possible yet work still remains as my design has some unproven assumptions.

Thats what I'm on here for. I realize that for me to be successful I need to make your life, the drivers and owners, more profitable and easier. What I'd like to do is list the design assumptions that I have as Im not comfortable going into all the bread and butter of my design so as to protect against competition. Please comment on what you agree with or what you disagree with, or ask any questions you'd like. I really appriciate your time in helping me, I really only want to help the small business guy with costs here and to reduce fuel consumption.

Assumptions:

1) The bulk of tractor trailer business is done where the owner of the truck doesn't own the trailer. Additionally for large fleets there approximatly 3 times as many trailers as there are tractors. This prevents the trailer owner from applying aerodynamic devices to the trailer as he won't realize the cost benefit. This leads me to want to make a device that is sellable to the tractor operator and thus removable.


2) If the device is removable and the driver owns it, he must be able to store it in or on his cab. Thus, I'm designing this device to fit into a tent sized bag with a maximum dimension of 5'x8"x8". Would you be willing to put this into your cab? If not i'd have to design a fixture to sling this on the back, outside your cab.

3) Since this device is removable, how much time could you allocate to remove & install it every time you un/load? My current goal is under 3 minutes by one guy. How often would you have to do this? Every time you hooked up to a dock? Could this be taken care of by dock loaders at say a large facility such as UPS? How much room would we have to install this thing? My guess is 10' x 10'. (The size of the thing is going to be 102"wide by 9' tall by 5' aft of the trailer to comply with DOT regs)

4) Being as its removable, it may come off by accident which is not acceptable. My current mitigation strategy is to design and install a four point harness with an electrical circuit that measures strap tension and alerts the driver when its at a safe level. (crank will be provided). The material this is made out of won't damage any property if it falls off. Needless to say there will have to be insurance? Anybody have experience with insurance provisions for this sort of thing?

5) Cost. As what really matters is how long it takes for each truck to make up the cost of the purchase. My competition is toting about a year, but I want this to pay for itself for the average truck driver in approximately 3 months with the cost tied to fuel prices. Expect it to cost around 3300k (Absoultly not final). Is this reasonable?

6) Sales. Would it be feasible to go from truck stop to truck stop selling these? Or do I need to hire some bozo sales people?

Questions:

1) One thing I haven't been able to come up with a good answer for is why the side skirts have been successful and the boat tails have not been? This keeps me up at night as I fear I've missed something.

2) As part of the circuit I've already designed to measure strap tension I can get a lot more capability out of it and so for a slight amount of money i can have it be solar powered, with night time running lights, measurement of environmental conditions and GPS coordinates, and can wirelessly upload data via wifi and downloadable firmware, and also so you can check the status of the devices from your phone or trucks computer? What concerns do you have with this? Privacy? My main goals with this are theft protection and additionally so I can make sure a driver installed the thing properly (strap tension), my main concern is how often free wifi with no password is available while you're on the road?

Thanks for taking the time to read this. I'm looking forward to your feedback and suggestions. I want to get this thing rolling!!!!