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Topic: Aerodynamics of V-nose units

Posted By: mrradio on 02/01/10 07:27am

Jayco has a new lightweight V-nose unit out. Very expensive but interesting approach with LED lights, internal heat pump style a/c and heat etc very sleek and very light for a v nose.

I got to wondering, do V=nose units have significantly better aerodyanmics than flat front trailers? Or is it more about creating a litte more room.

Thank you


Posted By: Burp on 02/01/10 07:37am

Engineers may correct me on this one. No matter what type of front end you have, it still needs to push the same amount of air out of the way. That is the majority of the air resistance on a TT (or anything else). The v-nose may improve the drag coefficent and help to some degree but not to the degree you expect. Semis get benefits in aerodynamics by cutting down the gap between the tractor and trailer and eliminating any drag. This is usually done by smoothing out the exterior edges of the tractor.


2007 Winnebago Voyage 33V (Workhorse, W20)
2008 Suzuki S83 (VS1400)

Me, the Wife , Sarah
Places we have camped in an RV



Posted By: eric james on 02/01/10 09:00am

I've pulled an unloaded 16' V-Nose cargo trailer and got the same mpg as my 6000 lbs slope nosed Passport. I was surprised.

As posted, you still have to move the air out of the way. It's still physics.


2009 Keystone Passport UL 290BH
2003 Ford Expedition EB 5.4L/3.73




Posted By: jmtandem on 02/01/10 09:38am

mrradio,

Since the trailer is following your tow vehicle, the TV is taking the brunt of air resistance, not the trailer. I doubt it will make much difference and is more a marketing ploy.


'05 Dodge Cummins 4x4 dually 3500 white quadcab auto long bed.
'09 299bhs Tango.


Posted By: RandACampin on 02/01/10 09:20am

Physics or aerodynamics. I will agree that the same amount of air need to be moved however the v-shaped nose will move that air in a much easier and efficient manner, and should technically improve performance and gas milage.

How much improvement is the question, will it be noticable of not?


Posted By: beemerphile1 on 02/01/10 09:36am

The V nose trailer has increased frontal area so any benefit to the shape is most likely counteracted by the larger frontal area. The larger frontal area creates more drag. The worst factor is that it probably has a chopped off, flat rear like most all trailers. The flat rear creates lots of turbulence and a suction effect. Ever feel the suction from a semi?

The most aerodynamic shaped trailer is the tear drop shape. Ever see a rain drop fall? It is round in the front tapered to a point in the rear. Nature teaches us the most aerodynamic shape.

The only real benefit to a V nosed trailer is that it uses some area on the tongue that is otherwise wasted on many trailers.

* This post was edited 02/01/10 10:05am by beemerphile1 *


"Liberty lies in the hearts of men and women; when it dies there, no constitution, no law, no court can even do much to help it..."
Judge Learned Hand


2006 Weekend Warrior FK1900/1998 Ford E150 4.6L = 8MPG
2009 Aliner Sport/2009 Pontiac Vibe 1.8L = 22MPG



Posted By: willald on 02/01/10 10:38am

I would think the V nose would help some with aerodynamics, but as others have suggested, the difference may well be so small you won't notice it.

I've looked at these, and am not crazy about the design. Main reason being, the V nose on the front takes up a lot of space you otherwise have on the A frame, and that really limits your choices as far as what hitches you can use. The ones I looked at, pretty much the only hitch that would work was an Equalizer. Everything else (Dual Cam, conventional WD, Pullrite, Hensley, ProPride) either would not fit/work at all, or would require cutting and hacking on the figerglas side on the front to make the WD snap-up brackets fit.

Its unfortunate, too, 'cause I really like the floorplan design some of them have, with a quad bunkhouse up front in that V nose, and queen bedroom in the back.


Will & Angela
2 children that love camping, Stephen & Allison
2012 FR Georgetown 351DS on F53 (V10) Chassis
Our Rig


Posted By: beemerphile1 on 02/01/10 10:41am

Mickeyfan0805 wrote:

...I haven't seen anyone saying 'Hey, look at our v-nose units, they'll be great on your gas mileage.' I'd want to see someone claim it and prove it before I bought something based on that expectation.


I don't believe you will ever see anyone make that claim because it would be a lie. The just build it and let you assume whatever you wish. If the potential buyer makes the purchase because they assume it is more aerodynamic, that is not the manufacturers fault.


Posted By: beemerphile1 on 02/01/10 12:50pm

pete42 wrote:

Are you people saying a flat-nosed trailer pulls the same as a vee-nosed trailer?

try holding a flat 4X8 sheet of plywood into the relative wind while standing on oh I don't know say a hay wagon going 40 mph.

then cut the 4X8 sheet of plywood arange it into a vee shape repete the above test.

I will drive the truck pulling the wagon if someone will volenteer to hold the plywood.


I won't try to hold either one, but you are missing something important.

By taking a 8 foot wide sheet and forming a vee, you have a narrower width, so yes it makes sense that you would have less resistance. In order to maintain the original width of the trailer, you would need a much wider sheet, maybe ten or twelve feet. Consequently you actually increase the frontal area which counteracts the benefit of the vee.


Posted By: pete42 on 02/01/10 11:56am

Are you people saying a flat-nosed trailer pulls the same as a vee-nosed trailer?

try holding a flat 4X8 sheet of plywood into the relative wind while standing on oh I don't know say a hay wagon going 40 mph.

then cut the 4X8 sheet of plywood arange it into a vee shape repete the above test.

I will drive the truck pulling the wagon if someone will volenteer to hold the plywood.






Posted By: webslave on 02/01/10 09:56am

As mentioned above, the V nose will help some, in theory. The wind going around your TV meets, in a turbulent manner, in the area immediately behind it and, almost, on the nose of your TT. The V nose should aid in cutting through that turbulence. The fact of the matter is, that the V nose is neither sharp enough, nor at an angle sharp enough, to really make a mpg difference that is discernible. The large tractor trailer trucks mitigate some of that turbulence by the use of deflectors to make that turbulence occur on the trailer's sides and top. This leaves only one area of "drag" at the end of the trailer, hence, they see a mpg increase by getting rid of both the vortex at the rear of their cab and the turbulence in front of their trailer. Your TV / TT combination can't get around the two areas of drag that are inherent in the combination; the end of your TV and the end of your TT. In effect, the TV / TT has air to push away from both the TV and the TT fronts, and the drag incurred at the back of your TV and TT. The air in front of both acts as a barrier you have to push through and the drag at the back creates a suction vortex that you have to pull out of with both... The V nose helps, but, not in a manner that, IMHO, makes up for the strange shaped interiors inside. The most usable volume is a box. If I'm not going to see a significant and lasting mpg improvement, I'll stay with the "maximized" space of the box As was also mentioned, the most effective shape would be bordering on a teardrop shape, both for the TV and the TT. Take a look at some of the "fuel efficiency" winners at the engineering colleges. Extreme sharp angles in front to slice the air and long tapering rear ends to smooth the air flow in back to eliminate the vortex at the rear.


My 2 cents, your mileage may vary...

Don
Bronwyn
2 Cats; J-Lo and Ragamuffin

2011 Keystone Cougar 318SAB
2011 Ram 2500 Longhorn CTD HO
Built in brake controller and exhaust brake
Tri Glide TrailAir Pinbox with a B&W Companion Hitch



Posted By: charlestonsouthern on 02/01/10 02:52pm

I just purchased a new 2509C Hi-Lo and had it shipped down from Ohio. We have'nt used it yet because it is winterized. But I am hoping this camper will help me achieve better gas mileage based on the manufacturer's claims. As to the turbulence at the end of the camper, I notice that the Hi-Lo has a very rounded fiberglass end cap. So does the front cap. Do you think rounding off the end cap of campers will help with the drag?

Mannie


Posted By: Mickeyfan0805 on 02/01/10 02:05pm

pete42 wrote:

Are you people saying a flat-nosed trailer pulls the same as a vee-nosed trailer?

try holding a flat 4X8 sheet of plywood into the relative wind while standing on oh I don't know say a hay wagon going 40 mph.

then cut the 4X8 sheet of plywood arange it into a vee shape repete the above test.

I will drive the truck pulling the wagon if someone will volenteer to hold the plywood.


Can't speak for others, but that is not what I am saying - I have no doubt that aerodynamic design matters in drag and resistance, and thus fuel efficiency (there's a reason airplanes aren't shaped like buses!). All I'm suggesting is that it is hard to discern, universally, which design will be the most efficient. There are too many variables that can change from one situation to the next.


Posted By: Mickeyfan0805 on 02/01/10 10:11am

Not being an aerodynamic engineer, my very novice reaction would be to think that much of this would depend on the manner in which the air is coming off the rear of your tow vehicle. The aerodynamics of each vehicle will be different. An SUV towing will have a higher airflow coming off the back of the vehicle which could mean the air actually ends up putting some down-force on the slanted front of a sloped trailer like a passport. On a pick-up, that air flow has started dropping already at the back of the cab (although, contrary to a frequent perspective, my understanding is that it is designed to go over the back rail of the bed). This airflow is thus at a much lower point when it trails off the back of the TV and would probably climb more naturally up the slope of a curved front. I would expect that distinctions such as this would change the efficacy of any given trailer design.

My bigger question would be the effect of tongue weight. Many of the v-noes unites I've seen put a significantly greater weight on tongue - I don't know how that might play into this as well.

With all that said - I haven't seen anyone saying 'Hey, look at our v-nose units, they'll be great on your gas mileage.' I'd want to see someone claim it and prove it before I bought something based on that expectation.


Posted By: Cool Canuck on 02/03/10 10:26pm

When flying boats on the side of a float plane, we usually tie them on stern to front. There is more drag caused by the turbulence off the flat back end than a flat front end. The flat front end will create a bubble for the air or fluid to flow around. You can find many aircraft with flat front ends, but they all taper off at the back.

Many factors at work. My current trailer is 5ft. longer, a foot higher and 2,000 lbs heavier than my last. Yet I get 2 mpg better mileage with the new one. That's 20% which is huge. It is all about aerodynamics and drag. Rounded corners, enclosed underbelly and smooth walls all help to make a difference. Neither has a pointed front end. Nor back for that matter. :-)
Intuition might tell us that a point is going to slice through a fluid better; and it will, however, a pointy back end will have a better drag coefficient.


04 Everest 343L
2011 F250 PSD CC

SOLD - 01 F250 PSD S/C S/B
SOLD - 00 Jayco 313


Posted By: aftermath on 02/03/10 04:38pm

I don't buy the raindrop argument. A drop is shaped the way that it is because of gravity and surface tension. I don't think it was some "plan" to make it fall efficiently.

I do buy into the prevailing argument that it has more to do with many other factors and not just the shape of the front end. I am now pulling an Airstream. I get the same mileage as I did with my other trailer that was 2000 pounds lighter, 4 feet shorter and a half a foot more narrow. Lots of factors working here. The shape of the front compared to the flat (slightly sloped) front end, the shape of the back, the lower profile, the enclosed bottom and so on. Pretty technical stuff if you give it much thought.


2008 Toyota Tundra, Double Cab, 5.7L V8
2006 Airstream 25 FB SE
Equalizer Hitch
Prodigy Controler


Posted By: aftermath on 02/03/10 04:42pm

And here is another argument. The V nose just looks like it should be more efficient. It is like the guy who drives his pick up with the tailgate down because it just looks like it would allow more air flow hence better mileage. Or the guy who tosses his tailgate and gets one of those net things. The problem here is that the engineers who design the trucks design them for maximum efficiency with the tailgates UP! Take away the tailgate and you increase turbulence thus reducing mileage.

This won't matter to the folks that just "feel" it is a better way to go. Kind of like any other "brand" argument. We all feel as though we are right. Of course, I am guilty too!


Posted By: nny12972 on 02/02/10 04:47am

I've towed both many tens of thousands of miles---both approx. same size and weight.....only noticeable difference I've seen is only slightly better mpg in calm or a straight-on head wind....actually get less mpg & I've "felt" that cross-wind was harder to drive in with the V-nose.
J


Posted By: beemerphile1 on 02/01/10 04:55pm

charlestonsouthern wrote:

I just purchased a new 2509C Hi-Lo and had it shipped down from Ohio...Do you think rounding off the end cap of campers will help with the drag?

Mannie


It may help, only a wind tunnel knows for sure. But if you can reduce the turbulence at the rear of the trailer it will have less drag. Less drag = better aerodynamic efficiency. The Hi-Lo is more aerodynamic primarily because it has much less frontal area, similar to a Pup.

BTW a good friend of mine delivers Hi-Lo. Was the driver's name Tom?


Posted By: beemerphile1 on 02/04/10 06:22am

Study of aerodynamics is kind of a hobby of mine.

Like I stated earlier, I don't think the V-nose is of much benefit, but there are many improvements that I think we will be seeing adopted more in the near future. Many trailers, like mine, start at one height and go up to where they are higher in the rear. That is the exact opposite of how they should be made. If the trailer starts out higher and then tapers toward the rear it would be much more slippery. The vents and typical air conditioner units would then be out of the main air blast. When the roof slopes up toward the rear, that actually turns the roof into frontal area. Most RVs are chopped off and flat in the rear, that V would do a lot of good in the rear, probably more so than the front.

For the smoothest shape think of a teardrop with all windows, vents, air conditioners built flush with the body, so there is nothing to create turbulence and drag.

A large rounded front tapering to a smaller rear area provide the smoothest air flow.

Be careful when comparing the shape of an RV to the shape of a plane. Planes are designed to have a smooth air flow but the primary concerns are lift and stability, not smooth aerodynamics. An RV gets it's stability from being on the ground and doesn't have to be concerned with falling from the sky.

Also, when traveling at 35mph in still air, aerodynamics is a non-issue. At speeds up to 55 mph it does become more of an issue. At speeds above 55 it becomes an important issue, probably more so than weight. On flat ground, an 8,000 pound slippery trailer will give better fuel economy at 70 mph than a 5,000 pound square box.

* This post was edited 02/04/10 06:30am by beemerphile1 *


Posted By: beemerphile1 on 02/04/10 05:23pm

webslave wrote:

The only reason for the mention of airplanes and sails was to reference the "fluid" like dynamics of air over and around objects. It is the low pressure created above the wings or the curvature of the sail that keeps the plane in the air or the sailboat moving. The air going around the side of a TT has the same propensity for "motion", albeit somewhat mitigated by the friction of the tires on the ground. That mitigation is not completely negated, however, hence the "push" of a tractor trailer's air flow against the side of the TV and TT. My only thought was that it would be nice to see airflow dynamics (wind tunnel) results of the two different types of nose designs with regards to the external yaw forces induced on the TT and how the flow impinges on the TT's sides... The resultant differences would be negligible in any case at the "air speeds" that we tow at, but, the wind tunnel test results would interest me


Agreed, would interest me also. I was just pointing out that the shape of an airplane has other considerations besides making it as aerodynamically slippery as possible.


Posted By: pete42 on 02/03/10 09:48pm

webslave wrote:

..since the V nose pushes the air out to the sides, does it create a vacuum next to the side of the TT as a wing does? That is how a wing or sail works, to create lift from the suction...what happens when a truck passes, does the increased pressure from the truck side produce "lift" or suction on the curb side of TT? Would be interesting to see.


I believe the flat side of the airplane wing doesn't create a vacuum.
the curved top creates the vacuum just as the curve in a sail on a sailboat.

I may be wrong but I am both a commercial pilot and a bareboat charter certificate holder.

I would like to throw this out for consideration way back in the last century I was in the submarine service, the sub I was on had a pointed nose then "they" came up with the rounded nose "they" found it went through the water better so maybe we should make our trailers more whale shaped instead of pointed?

pete

* This post was edited 02/03/10 09:56pm by pete42 *


Posted By: LarryJM on 04/29/10 04:42am

mrradio wrote:

Jayco has a new lightweight V-nose unit out. Very expensive but interesting approach with LED lights, internal heat pump style a/c and heat etc very sleek and very light for a v nose.

I got to wondering, do V=nose units have significantly better aerodyanmics than flat front trailers? Or is it more about creating a litte more room.

Thank you


IMHO being a novice on real aerodynamics I think all this front end stuff is addressing like 25% of the areodynamic issues and then only maybe improving that like 10%. It doesn't help the TV areodynamics, the undercarriage/wheel turbulence or the rear of the TT turbulence concerns so any actual improvement is probably impossible to see in mpg improvements except maybe in the second or third or fourth decimal place in you mpg numbers.

Larry


2001 standard box 7.3L E-350 PSD Van with 4.10 rear and 2007 Holiday Rambler Aluma-Lite 8306S Been RV'ing since 1974.
RAINKAP INSTALL////ETERNABOND INSTALL



Posted By: LarryJM on 04/29/10 04:48am

aftermath wrote:

I don't buy the raindrop argument. A drop is shaped the way that it is because of gravity and surface tension. I don't think it was some "plan" to make it fall efficiently.

IMO the raindrop analogy is very good since it's also mainly the aerodymanics of it falling than determines the shape with the gravity and surface tension being constants. The raindrop shape is also what the wings on an airplane are and the tear drop shape has been shown to be the most aerodynamic design.

I do buy into the prevailing argument that it has more to do with many other factors and not just the shape of the front end. I am now pulling an Airstream. I get the same mileage as I did with my other trailer that was 2000 pounds lighter, 4 feet shorter and a half a foot more narrow. Lots of factors working here. The shape of the front compared to the flat (slightly sloped) front end, the shape of the back, the lower profile, the enclosed bottom and so on. Pretty technical stuff if you give it much thought.


Larry


Posted By: advntrs on 02/02/10 07:10am

We pull a 28' VR-1 by Keystone with a F-350 Diesel. Prior to this, we had a 28' "flat nosed" TT.

We have noticed absolutely no difference in MPG (11-13)and have not experienced any difference in handling in cross winds. However, we LOVE the extra large two sink bathroom up front.

They will try to sell you on this TT being a "high mileage" unit, but it truly is not.....Just like the rest.

Fill-up and enjoy!!!!!


08 F-350 Super Crew 6.4
08 28' Keystone VR-1
"Every man dies, but not every man truly lives"



Posted By: webslave on 02/01/10 05:30pm

The sheet of plywood is really not that good of an analogy... If you look at most modern day "boxes", the nose is actually sloped. My FunFinder has a rounded sloped nose, but, the slope is up rather than to the sides and the slope is not so pronounced that it cuts a lot of interior space out of the TT as the V nose models do (the slope is in the front wall over the bed). That slope eliminates the "flat nose" and does alleviate some of the brute force required to cut through the air. In fact, it is much more aerodynamic than the "brick" of a Jeep pulling it. The reduction in drag coefficient between the slope nose of most trailers and the V nose configuration is, IMHO, not enough to see any statistically significant increase in mpg. I would find it interesting to see wind tunnel tests on the V nose...since the V nose pushes the air out to the sides, does it create a vacuum next to the side of the TT as a wing does? That is how a wing or sail works, to create lift from the suction...what happens when a truck passes, does the increased pressure from the truck side produce "lift" or suction on the curb side of TT? Would be interesting to see.


Posted By: webslave on 02/04/10 05:14pm

The only reason for the mention of airplanes and sails was to reference the "fluid" like dynamics of air over and around objects. It is the low pressure created above the wings or the curvature of the sail that keeps the plane in the air or the sailboat moving. The air going around the side of a TT has the same propensity for "motion", albeit somewhat mitigated by the friction of the tires on the ground. That mitigation is not completely negated, however, hence the "push" of a tractor trailer's air flow against the side of the TV and TT. My only thought was that it would be nice to see airflow dynamics (wind tunnel) results of the two different types of nose designs with regards to the external yaw forces induced on the TT and how the flow impinges on the TT's sides... The resultant differences would be negligible in any case at the "air speeds" that we tow at, but, the wind tunnel test results would interest me


Posted By: bowmaker on 02/03/10 01:37pm

We have a VR1 31 footer but I can't remember the model but loaded it is about 9000 pounds. Before that we had a 26 foot Trailite that loaded was about 6000 pounds. With the same truck I got about 11 MPG with the Traillite and about 10 MPG with the VR1. I am guessing that there is a little bite of fuel savings because that 3000 pounds only costs me about 1 MPG. No one has mentioned it yet but I do notice a real difference when meeting a Semi on a 2 lane road. There is not nearly as much reaction to the air turbulence with the VR1 as with the more square Trail Lite. Our VR1 has the closet up front in the V and we think it is great, not only does it V but it also slopes down towards the front also. It is very large with almost too much room, for clothes, bedding, a vacuum, a foot stool and even a little room for fly rods.


Posted By: pasusan on 02/02/10 04:53am

nny12972 wrote:

I've towed both many tens of thousands of miles---both approx. same size and weight.....only noticeable difference I've seen is only slightly better mpg in calm or a straight-on head wind....actually get less mpg & I've "felt" that cross-wind was harder to drive in with the V-nose.
J


I vote for the voice of experience.


Trip Pics

"I'm out here to enjoy nature -- don't talk to me about the environment!" ~Denny Crane

Susan & Ben ~
84 Bronco & 90 Award Classic 23 joined with a Hensley Cub



Posted By: new2traveling on 04/28/10 11:22pm

pete42 wrote:

I believe the flat side of the airplane wing doesn't create a vacuum.
the curved top creates the vacuum just as the curve in a sail on a sailboat.

Well here’s my $0.02 worth for the argument.

1) The top of the wing is curved. The air flowing around it is a fluid. To produce lift the air flowing over the top of the wing has to travel faster that the air under the wing. This reduces the pressure on top of the wing. That is the called the Bernoulli principal.

2) There have been both real world tests and theories on semi’s where a open “Boat Tail” of panels have been attached to the rear of the trailer. Now there was no end cap placed on the boat tail. It was left open, which in my opinion would create a vacuum behind the add on. How well this add on worked I don’t know.

Anyway you look at it you are going to have a large mass being pulled through the air which will create a large amount of drag.

And now straight from the Wikipedia

Bernoulli's principle wrote:


http://en.wikipedia.org/wiki/Bernoulli%27s_principle

In fluid dynamics, Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. Bernoulli's principle is named after the Dutch-Swiss mathematician Daniel Bernoulli who published his principle in his book Hydrodynamica in 1738.

Bernoulli's principle can be applied to various types of fluid flow, resulting in what is loosely denoted as Bernoulli's equation. In fact, there are different forms of the Bernoulli equation for different types of flow. The simple form of Bernoulli's principle is valid for incompressible flows (e.g. most liquid flows) and also for compressible flows (e.g. gases) moving at low Mach numbers. More advanced forms may in some cases be applied to compressible flows at higher Mach numbers (see the derivations of the Bernoulli equation).
Bernoulli's principle can be derived from the principle of conservation of energy. This states that in a steady flow the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. This requires that the sum of kinetic energy and potential energy remain constant. If the fluid is flowing out of a reservoir the sum of all forms of energy is the same on all streamlines because in a reservoir the energy per unit mass (the sum of pressure and gravitational potential ? g h) is the same everywhere.

Fluid particles are subject only to pressure and their own weight. If a fluid is flowing horizontally and along a section of a streamline, where the speed increases it can only be because the fluid on that section has moved from a region of higher pressure to a region of lower pressure; and if its speed decreases, it can only be because it has moved from a region of lower pressure to a region of higher pressure. Consequently, within a fluid flowing horizontally, the highest speed occurs where the pressure is lowest, and the lowest speed occurs where the pressure is highest.



Posted By: Ron Gratz on 04/29/10 08:52am

Are raindrops shaped like teardrops?


Posted By: atreis on 05/01/10 05:26am

The backs are still flat. That vacuum really sucks. I highly doubt there would be a significant difference in mileage.


2009 Trail-Sport TS21RBH
2008 Toyota Sienna



Posted By: atreis on 05/03/10 05:22pm

pete42 wrote:

Ateris maybe we should go outside today and try to see if the raindrops are hamburger bun shaped or more like the common pictured ones.

I'll bet you I would be all wet at the end of testing, which by-the-way I have been before.

to other posters Ateris and I live about 15 miles apart we have never met but I'm sure he's a nice person. oh yea it's raining here today.

PETE


Ha! Raining wasn't the word for it! What a waste of a good weekend. (I did try to look at the drops this weekend, but couldn't. They move too fast.)

Today it's bright and sunny... Shame it's also Monday...


Posted By: 92DakotaHD on 05/01/10 08:29am

jmtandem wrote:

mrradio,

Since the trailer is following your tow vehicle, the TV is taking the brunt of air resistance, not the trailer. I doubt it will make much difference and is more a marketing ploy.


I'm with you on that one.

pete42 wrote:

Are you people saying a flat-nosed trailer pulls the same as a vee-nosed trailer?

try holding a flat 4X8 sheet of plywood into the relative wind while standing on oh I don't know say a hay wagon going 40 mph.

then cut the 4X8 sheet of plywood arange it into a vee shape repete the above test.

I will drive the truck pulling the wagon if someone will volenteer to hold the plywood.


See above, hold the plywood 4-5' behind an SUV punching a huge hole in the air.

atreis wrote:

The backs are still flat. That vacuum really sucks. I highly doubt there would be a significant difference in mileage.


Yeah, that's true there. Being on a motorcycle you can really get an idea of how much air disturbance there is around/behind larger vehicles


1992 Dakota 2WD 5.9L V8 (NOT Stock)
Headers, FMS Injectors, Ported TB, MP PCM (not good for towing),
2005 Chevy Tahoe Z71- Bermuda Blue, A/T Revo 265/70 "E"
Prodigy Controller

08 Passport 24RB, YAY SPACE!

Gone Racing!

A newbie, any tips please share!


Posted By: pete42 on 05/01/10 07:13am

Ateris maybe we should go outside today and try to see if the raindrops are hamburger bun shaped or more like the common pictured ones.

I'll bet you I would be all wet at the end of testing, which by-the-way I have been before.

to other posters Ateris and I live about 15 miles apart we have never met but I'm sure he's a nice person. oh yea it's raining here today.

PETE


Posted By: LarryJM on 04/29/10 10:57am



Just proves I know "JACK" about raindrops

Larry


Posted By: MeandMyLabs on 05/01/10 07:46am

I guess I will jump in here. It has been a proven fact that barring the weight difference when using identically shaped trailer fronts and equal tow vehicles that a trailer measuring 22ft will displace the same amount of air as a 30ft when traveling. However, there are sooo very many aerodynamic variables which dramatically change the data results.

As others have stated in this post, the TV is splitting the envelope of air and it's aerodynamic properties have huge results on test data. Most TV are designed to allow the turbulence air foil which is created behind the vehicle when not towing to be complimentary (as much as possible) and will somewhat help to provide better performance and fuel mileage. When towing a tall trailer, this turbulence is redirected and disturbed dramatically. The size of the turbulence is greatly altered by the configuration of your tow vehicle (van Vs pickup etc.) and the trailer you are towing. Also, these factors do not take anything into account for alternate forces such as side winds and inclines.

Bottom line is the V-nose style will probably increase slightly the performance of your TV but not dramatically enough to use a smaller TV. Weight is weight and side winds can be scary and unpredictable.

The innovative v-nose designs of trailers are interesting and do offer some creative floor plan concepts, which can be very inviting for some buyers, but I would not base any decision solely on aerodynamic performance or you might be disappointed.


2013 XLR 27 HFS
2009 Chevrolet 2500 HD 6.0 L
Yamaha 2400is
Champion 4000 watt
Yamaha Zuma 50cc
Kawasaki Brute Force 650
Camping Buddy - Raji (yellow lab)



Posted By: biker4life on 04/29/10 08:14pm

weight is weight, a brick is a brick, cut air better, maybe, better fuel enonomy, probably not. but, you do get extra floor space!


Posted By: ripperoo on 04/29/10 06:50am

LarryJM wrote:

aftermath wrote:

I don't buy the raindrop argument. A drop is shaped the way that it is because of gravity and surface tension. I don't think it was some "plan" to make it fall efficiently.

IMO the raindrop analogy is very good since it's also mainly the aerodymanics of it falling than determines the shape with the gravity and surface tension being constants. The raindrop shape is also what the wings on an airplane are and the tear drop shape has been shown to be the most aerodynamic design.

I do buy into the prevailing argument that it has more to do with many other factors and not just the shape of the front end. I am now pulling an Airstream. I get the same mileage as I did with my other trailer that was 2000 pounds lighter, 4 feet shorter and a half a foot more narrow. Lots of factors working here. The shape of the front compared to the flat (slightly sloped) front end, the shape of the back, the lower profile, the enclosed bottom and so on. Pretty technical stuff if you give it much thought.


Larry



I agree Larry, the very fact that a drop of water is moldable, is why it becomes that shape. It becomes the most efficient shape by nature, due to all of the factors affecting it's shape.


2012 Ford F250 Super Duty, SC 4x4 XLT, 6.2L, 3.73 gears
2011 Keystone Sprinter Select 29BH


Posted By: Phathead on 05/03/10 07:04pm

Lots of smart people on here. I have one question along these lines. Would a camper top on a truck with a large spoiler to get the air up and over the trailer front be beneficial by moving the turblance to the rear of trailer only. Or would the spoiler be mearly replacing the front of the trailer and the same turbulance\resistance still be there?


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