It only deflected money from your bank account to the manufacturer's, however this video will deflect a lot more money back to your loyal viewers. Many thanks.
Thanks for the video. It is very informative. The American Trucking Association along with truck and trailer manufacturers determined a long time ago that its not just deflection of the air as the combination vehicle is moving. The critical issues are the gap between truck and trailer, the width and the shape of the gap is key. Within this gap, the faster the vehicle travels a turbulent negative air pressure is created causing drag. The keys to reducing that drag is to minimize the gap as much as possible, have the rear body of the tow vehicle closely match the front profile of the trailer and then add the deflector(s) as needed to match the front profile of the trailer. You said you had wind noise, an engineer told me a long time ago, noise is wasted energy. (Ever notice that today's diesel engines are considerably quieter than yesterday's... same concept.) Everything you said and did made sense to me. And you were correct in the beginning, if you had a shell on your bed with that deflector you probably would have seen a positive result. If you had a large SUV you probably would have seen a positive result. There was way too much gap between the truck and trailer and you had no means to move the deflector closer to the trailer and it was not enough to compensate for the geometric differences in shape of the truck bed as compared to the camper. Thank again for another good and informative video. Best regards! Mark
@@WFSC923 I would say probably not really in this case. Tonneaus were tested by a college project group and found to be about the best thing for increasing fuel mileage on bare pickups not pulling a trailer. The next best was bed open with the tailgate closed. The worst were bed open tailgate off and with a cab high topper or cap or shell "whatever you want to call them" on a pickup truck. The best setup for semi trucks is said to be with the trailer within about 18" from the deflector. As others have said this fellers gap between the deflector & trailer was way too much. I agree with Mark Philpott's analysis 👍
I mounted mine to the back of my camper shell so it's 3 feet away from the face of the trailer and it did help add 1.5 mpg. Truck + trailer = 14 mpg. Truck + shell + trailer = 15.5 mpg. Truck + shell + wing + trailer = 17 mpg. And, I got it for $80 used on Craigslist!
Thanks for the info! Like you said - the long gap between the deflector and camper is probably a problem. I wouldn't be surprised if the turbulence and low pressure zone behind the deflector is worse than from the naked cab. The deflector might also be adding a second high-pressure drag zone. A pickup topper with a deflector (or a wedge topper) would make your combined rig cleaner.
Thanks for taking one for the team. The issue, from what I could find is that the deflector on the tow vehicle roof isn't back far enough to direct the air over the trailer and is essentially doing exactly what you said, creating drag. I read some comments about this issue as it relates to truck caps and the consensus from long term towers was that with, or without a cap, gas mileage is pretty much the same. Thanks again.
Thanks for posting this, Marion. I was planning to buy a "wind deflector" but after I saw my video, I am canceling my plan to buy one. Thank you once again.
My 69 concord camper is an 18' BOX. I've thought about one of these. More though I'd like to install an extremely low to the ground front splitter on to my cattle guard. I know dragging excess and turbulent air under a race car is avoided at all costs.
In a previous business my wife and I had to tow a trailer from MN to NC to AZ and back every year. Actually, pretty much the same trailer you're showing, Rockwood Minilite. I have a friend who's a retired aeronautical engineer, worked on a number of projects including the B2 bomber. He told me most things just don't help. The most interesting thing he told me: it's not the air you're pushing but actually the air you're pulling that creates the biggest problem. It generates tremendous turbulence and therefore drag, at the back of the truck and massively for the tall flat back of the trailer.
Thank you so much for all of the factual data that you provide. You are amazing, you formulate a question, experiment, then formulate a conclusion without our personal biases. I always look for your videos when researching something for our trucks.
@@MarionBlair Have you Checked out TSD's RV card. It allows us to go through truck stops and saves up to $0.20 per gallon. You can also get quality def fluid straight from the pump. I have used it for about 6 months and have saved about $120 on fuel so far. Check it out www.tsdlogistics.com/services/fuel-program/
Thanks so much for all the hard work. Best testing I've seen done on these things! I have a fifth wheel and don't know how much different the results would be. But don't think I'm gonna mess with it. Excellent video and results!!!!!
Too much space between cab and trailer. Increased drag and turbulence = more fuel. PS I’m not a engineer nor do I play one on TV, I didn’t even stay at a Holiday Inn last night.
Agreed, from another non-engineer. I believe the outcome would have been more favorable on a 5th wheel vs the bumper pull travel trailer. If the bubble of compressed air at the front of the trailer reached the deflector then it would have broken the vacuum of the hole over the empty bed. If this setup was in a wind tunnel you would see a huge circulation of air that probably increased the wind load on the front of the trailer. This deflector is so far from the front of the trailer that it actually created a second flat backed vehicle and increased the vacuum on the rear of the truck. It's like how some people drop their tailgate for mileage, this was like adding a taller tailgate to the back of the truck. Thanks for the thorough analysis Marion. It will most likely save many lots of money.
Yes you are correct that his spacing between the deflector and trailer caused the added drag. I also am not an engineer, but I am a truck driver by trade. The wind deflector on a semi can literally make a 30% increase in fuel mileage. (I have seen it for the past 28 years.) I run a deflector on my van when I pull my 10x6 enclosed trailer. I have it at the very rear of the van and adjusted so the wind will deflect just high enough to land on top of the trailer. No deflector, 10.5 MPG with deflector 13MPG and I drive it like I stole it! I assure everyone that his data would show a much better result if he was towing with a van, or had a topper on the pickup.
This is a great video. This was the first one that came up. I am hauling my bumper pull trailer in the wind is killing me right now. I needed some real data to determine if I should buy one of these things. It turns out that wind deflector only increases that negative void space between the truck cab in the trailer front and that is where that pressure drop occurs and increases the drag. I would imagine if you had a truck bed camper that may be the wind deflector might be helpful at that point
Yes, the toppers that slope up to the back would probably save me a couple MPG. And then to go to the extreme, put this thing I test at the back of it. That would really help IMO. I actually got better mileage with the damn thing setting flap.
Thanks for the info. I have been wondering about the same deflector. I have a 2013 3500 Cummins and a 2019 Rockwood Ultra lite 2304DS. I'm getting the same average mpg (without) as you were getting. You saved me some $$$.
I think your conclusions are spot on. The bugs tell the story. I tow a fifth wheel and the deflector keeps the bugs off. Next summer I'll use your methods to test my setup for mpg.
Like you said, might work with a bed cap, pretty sure it was too far away from the camper to achieve its intended effect, as always, thanks for helping the rest of us out here
there's an invisible line between the top of the cabin and the top of the tailgate. you can mess with tailgate deflectors to change properties but, without a wind tunnel, you're operating blind. same thing with the camper attached. you would need access to a wind tunnel in order to know if what you were doing was right. seeing as wind tunnels aren't practical for the layman, the best thing to do is nothing at all. drive slower and steady... don't use your brakes and save your money for keeping the vehicle properly maintained. thanks for sharing though. this was interesting and a good conversation point.
I have an aeroshield from Australia. Mounted on my camper shell at the rear of my truck. I get 2 mph boost on flat roads but the real advantage is the stability of the trailer and the better control.
Removing the tailgate might save more $ than adding a roof mount wind deflector. I used to run an '80's K20 wo the tailgate. More aero. More visual. Less weight.
I am going to try a 4x8 sheet of plywood in the bed resting on about a 45 degree angle and see if it disrupts the negative air pressure. Next I was thinking that air deflectors right behind the cab, mounted in the bed to direct airflow into the negative air void might help. In the spring, I will definitely be trying things to reduce the negative air void. I get about 12mpg with my RAM 2500, Cummings diesel when pulling my Rockwood ROO. Without the ROO, I get about 23-24 mpg on the interstate at 65mph. I always drive 5mph below the speed limit in the right lane so everyone else has to pass me and I can just relax.
I would love to see you do a test like this with a fiberglass shell like the maroon one early in your video. Thinking about buying one to add storage on my extended RV trailering.
Marion, YOU DA MAN!! Thanks for doing this. I am now exploring ways to reduce the gap between the truck cab and camper. I was wondering if placing a spoiler on the rear of my RAM 2500 bed, placed lower than the cab roof would have any impact on eliminating the negative air pressure. I intend to experiment by using a piece of plywood placed on an angle (leaning against the tailgate) in the spring once I remove my camper from winter storage. Not sure what angle to use for the plywood. Any ideas would be appreciated. If the negative air pressure (makes sense, like an airfoil) is the issue, then perhaps directing air into the negative air pressure void would reduce the drag. Just thinking. Perhaps an airfoil on rear of truck near the trailer hitch directing air from under the truck upward into the negative air pressure area would have some impact.
I think anything you can put back there is better than nothing as I'm thinking like you on disrupting the negative air flow. I can tell you, when I put my canoe on the truck racks, my mileage improves. I'm going to do a video on that when I have time to decipher the data I've captured. I think a toper that slopes up as high as possible is the best thing but they are 2200 bucks or so and makes it difficult to get in the bed, but I think that would do the trick. Maybe even add a spoiler to the top of the topper near the back. Ugly yes, ha. For testing, I've considered building a plywood air foil like the 18 wheelers use that would butt up right close to the camper and just as high just to see. I bet it would improve mileage significantly. Man would it be ugly but just interested to see the difference.
Have you thought about putting it above the tale gate? That is if you have a Tunneau cover on your truck. Just a thought since the Travel trailer is farther away then a fifth wheel.
Deflectors really only help on fifth wheel setups, not bumper pull because the trailer is so far back there. Unfortunately, there's not much you can do on a bumper pull set up. I'm in the same predicament, but luckily I figured that fact out ahead of time.
The angle on that thing looks pretty aggressive, I wonder if lowering it down would help. You could sight down the plane of the deflector (like checking a 2x4 for straightness) until the top edge of the front of the trailer just comes into view. I think that and taping the front edge to make a smoother transition might make this thing actually work. I remember back in the '90s I'd see pickups (usually duallies) towing trailers with those stainless wings on top that had an upswept airfoil shape.
Thank yo for the thorough review. I own a fifth wheel and wont consider a deflector based on your results. I know the fifth wheel sits closer to the deflector but doubt it will have any material effect on mileage.
Have you tried one of the camper shells you mentioned at the beginning? I am towing a Rockwood Ultra Light 2304 DS which is even taller (and heavier if you are pulling a 21’) than your trailer. A friend has the Mini Light and he is getting a couple of miles a gallon better than I am.
I had a topper on a previous truck and got better fuel mileage than this one (with a much heavier longer camper) but never really compared with and without. I think it would be better with a topper.
I think the purpose for the wing is the reduce the circling turbulence gathered between tow vehicle and trailer. A wagon would be the worst for turbulence as it creates the most vacuum and sucks the most air into the space. A wing is most effective here when being as far as possible to the rear of the tow vehicle to kick up their air enough to skip over the space. I have a wing and find it helps 95kph and up ie helps me keep the speed limit of 100kph. Without it I find there is a wall of resistance approaching 95kph. For a ute or a sedan towing a caravan I can’t see the wing will be of benefit as there is a minimal space for turbulence and the wing is too far forward and the kicked up air would have blended back to normal air flow by the time it reaches the trailer.
It site way to far away from the trailer front. It creates a reverse vortex right into the pickup bed. The devices might be helpful on the top of a SUV.
@@MarionBlair Made my own once from some exterior mdo plywood. Used that for a couple of years till I found the one I wanted used. Paint it black nobody noticed it was wood.
thankyou for all your hard work and hours of testing , Im more interested in purchasing one of these to help with trailer sway when trucks passing me , wondering if it helps with getting the trailer more stable at hwy speeds , along with air bags, shocks , 10 ply tires, weight dist hitch , which i already have, , does it help distributing drag over the camper , i have a covered bed on my f150 crew cab , towing a 5000 lb camper ? and also was thing about air tabs also
Thank you. I recently bought a v nose cargo trailer to pull with my Yukon. Without the trailer, I get around 500 miles to a tank. With this 6x12 v nose trailer, I am getting less than 250. It is absolutely killing me on fuel as I travel for work. Any suggestions? I think if you added a cap on your truck, and put the wing on the back of the cap, it would work better. Just a guess though
What we did learn is that aero is really a big issue. Lol, put it under the front bumper as an air dam. Or just drive right behind a semi. You’ll get 14 MPG
Off-topic but Why do you idle while you refuel? Fuel tank needs to be sealed before ignition to pump the vacuum. Ignoring that will shorten the fuel pump and high pressure pump life cycles. Not to mention the carbon buildup raise caused by the wrong ignition cycle which itself is caused by ECU trying to compensate the excess oxygen coming from the tank.
@@MarionBlair The morale is not to run the fuel pump when the tank is open(i.e. you should turn the ignition off before refueling). The vent you mentioned is there to regulate the excess vacuum pressure inside the tank, it lets the air in not wise versa. Vent does not work when your tank is open, because there is no pressure. Pump needs a specific pressure inside the tank to work properly. Hope this helps, but if it is still somehow unclear just ignore it )
I made a home made version when I could not find anything to fit my vehicle, First attempt was beyond terrible worse mileage maybe 6 or so pulling a 28 foot travel trailer. Could not believe it., First stop I took it off the vehicle and cut it in half. Towing was better and mileage went up. So over the next few years of towing I've tweaked it to where I no longer fear getting passed by semi trucks the trailer is much more stable going down the road and mileage went up to 11 or so. The key for me was to keep on eye on the bug line on the front of the trailer, too much angle and you are pushing air over the front of the trailer too little and the bug line is too low. I focused on the bug line at the top 2 inches of the trailer give or take an inch. Now I made mine with large aluminum street signs that were being recycled. I towed with this setup on top of my Suburban for many years on different Suburbans and never had any problems. It was mounted directly into the roof rack on hinges to and cable screw tensioner to make adjustments. I've moved up to a fifth wheel and have not yet figured out how to mount it but I will try when I got some free time on my hands.
There are a lot of different opinions on this. The next time you’re on the highway you’ll see that most tractor trailers have wind deflectors. Actually more than 3 million trucks have wind deflectors on the roofs or integrated in the cab design. I guess they have them because they don’t work. If it’s too far from the cab it won’t work it will hurt the mileage.
Yes, if you watched the video, that's exactly the problem. They do work but only if they are next to the trailer like the 18 wheelers. Mine had a big gap between the deflector and the trailer. I also mentioned that it may work better with a 5th wheel.
I'm guessing if you are looking for some sort of improvement on mpg, you wanna find a way to add wind resistance/ aerodynamics to the giant sail you're pulling. Similar to what the big rigs are doing with their trailers.
@@MarionBlair Nice comparison and interesting data as well. I am not an engineer but I think this is a case of aerodynamics at play. I used to own a bumper pulled travel trailer with a front end "air dam" similar to yours (6,500lb GVWR). I pulled this trailer with a 2016 Ram 2500 crew cab pickup powered by a 6.7L Cummins diesel for 6,551 miles and used 586.2 gals of fuel (11.2 mpg). I now own a 10,000lb GVWR fifth wheel trailer, pulled by the same truck, and to-date I have pulled this rig for 19,805 miles and used 1,672.6 gals of fuel (11.8 mpg). While not a true "head to head" comparison, I think it is a partial comparison of the aerodynamics between the two different trailers.
Your air deflector is too far from the trailer. I have a short bed truck with a sliding hitch. My wind deflector is 2 feet from the front cap of the trailer. I get 1.25 average mpg increase at highway speed 65-70 mph. I have checked this using cruise control and my trucks dash mpg instant fuel data on 7-10 mile runs with and without deflector. Read the information that came with the deflector it must be placed close to the trailer to get any benefit.
The song goes - Dum DA dum dum dum.b.... You ,not the deflector. You are not supposed to have it 15 feet away. Putting it on the cab of the truck? Hello? No. dub. You ned a camper shell or an suv so it sits at back of vehicle near, NEAR, the trailer. You have it so wrong, of course it did not work. Maybe try it on the hood next time, it might do better.... Go back and re-do from start, the right way.
It only deflected money from your bank account to the manufacturer's, however this video will deflect a lot more money back to your loyal viewers. Many thanks.
Thanks for the video. It is very informative. The American Trucking Association along with truck and trailer manufacturers determined a long time ago that its not just deflection of the air as the combination vehicle is moving. The critical issues are the gap between truck and trailer, the width and the shape of the gap is key. Within this gap, the faster the vehicle travels a turbulent negative air pressure is created causing drag. The keys to reducing that drag is to minimize the gap as much as possible, have the rear body of the tow vehicle closely match the front profile of the trailer and then add the deflector(s) as needed to match the front profile of the trailer. You said you had wind noise, an engineer told me a long time ago, noise is wasted energy. (Ever notice that today's diesel engines are considerably quieter than yesterday's... same concept.) Everything you said and did made sense to me. And you were correct in the beginning, if you had a shell on your bed with that deflector you probably would have seen a positive result. If you had a large SUV you probably would have seen a positive result. There was way too much gap between the truck and trailer and you had no means to move the deflector closer to the trailer and it was not enough to compensate for the geometric differences in shape of the truck bed as compared to the camper. Thank again for another good and informative video. Best regards! Mark
Exactly the deflector being forward so far was causing more turbulence due to the slip stream effect.
Would a tonneau cover help?
@@WFSC923 I would say probably not really in this case. Tonneaus were tested by a college project group and found to be about the best thing for increasing fuel mileage on bare pickups not pulling a trailer. The next best was bed open with the tailgate closed. The worst were bed open tailgate off and with a cab high topper or cap or shell "whatever you want to call them" on a pickup truck. The best setup for semi trucks is said to be with the trailer within about 18" from the deflector. As others have said this fellers gap between the deflector & trailer was way too much. I agree with Mark Philpott's analysis 👍
I mounted mine to the back of my camper shell so it's 3 feet away from the face of the trailer and it did help add 1.5 mpg. Truck + trailer = 14 mpg. Truck + shell + trailer = 15.5 mpg. Truck + shell + wing + trailer = 17 mpg. And, I got it for $80 used on Craigslist!
Wow, yea, that I debated buying and still might buy a camper shell and do the same thing.
Can’t argue with the facts. Excellent work!
Thanks for the info!
Like you said - the long gap between the deflector and camper is probably a problem. I wouldn't be surprised if the turbulence and low pressure zone behind the deflector is worse than from the naked cab. The deflector might also be adding a second high-pressure drag zone.
A pickup topper with a deflector (or a wedge topper) would make your combined rig cleaner.
Thanks for taking one for the team. The issue, from what I could find is that the deflector on the tow vehicle roof isn't back far enough to direct the air over the trailer and is essentially doing exactly what you said, creating drag. I read some comments about this issue as it relates to truck caps and the consensus from long term towers was that with, or without a cap, gas mileage is pretty much the same. Thanks again.
I'm impressed by your attention to detail in getting your stats. You did a great job of controlling the variables.
Absolutely not a “failed” experiment. Very successful as you got a clear result. Very interesting thank you.
IFLS
Interesting! I’ve always wondered if those things worked or not. Thanks for all the work you did in putting this together!
Thanks for posting this, Marion. I was planning to buy a "wind deflector" but after I saw my video, I am canceling my plan to buy one. Thank you once again.
Glad I could help!
My 69 concord camper is an 18' BOX.
I've thought about one of these.
More though I'd like to install an extremely low to the ground front splitter on to my cattle guard.
I know dragging excess and turbulent air under a race car is avoided at all costs.
In a previous business my wife and I had to tow a trailer from MN to NC to AZ and back every year. Actually, pretty much the same trailer you're showing, Rockwood Minilite. I have a friend who's a retired aeronautical engineer, worked on a number of projects including the B2 bomber. He told me most things just don't help. The most interesting thing he told me: it's not the air you're pushing but actually the air you're pulling that creates the biggest problem. It generates tremendous turbulence and therefore drag, at the back of the truck and massively for the tall flat back of the trailer.
Surprised - I would have never thought you’d had those results. Many thanks!
Me neither
Thank you so much for all of the factual data that you provide. You are amazing, you formulate a question, experiment, then formulate a conclusion without our personal biases. I always look for your videos when researching something for our trucks.
Appreciate that.
@@MarionBlair Have you Checked out TSD's RV card. It allows us to go through truck stops and saves up to $0.20 per gallon. You can also get quality def fluid straight from the pump. I have used it for about 6 months and have saved about $120 on fuel so far. Check it out www.tsdlogistics.com/services/fuel-program/
Thanks so much for all the hard work. Best testing I've seen done on these things! I have a fifth wheel and don't know how much different the results would be. But don't think I'm gonna mess with it. Excellent video and results!!!!!
Too much space between cab and trailer. Increased drag and turbulence = more fuel. PS I’m not a engineer nor do I play one on TV, I didn’t even stay at a Holiday Inn last night.
Agreed, from another non-engineer. I believe the outcome would have been more favorable on a 5th wheel vs the bumper pull travel trailer. If the bubble of compressed air at the front of the trailer reached the deflector then it would have broken the vacuum of the hole over the empty bed. If this setup was in a wind tunnel you would see a huge circulation of air that probably increased the wind load on the front of the trailer. This deflector is so far from the front of the trailer that it actually created a second flat backed vehicle and increased the vacuum on the rear of the truck. It's like how some people drop their tailgate for mileage, this was like adding a taller tailgate to the back of the truck. Thanks for the thorough analysis Marion. It will most likely save many lots of money.
Yup. The giant void behind the deflector just makes a low pressure point, thus creating a vacuum and drag.
Yes you are correct that his spacing between the deflector and trailer caused the added drag. I also am not an engineer, but I am a truck driver by trade. The wind deflector on a semi can literally make a 30% increase in fuel mileage. (I have seen it for the past 28 years.)
I run a deflector on my van when I pull my 10x6 enclosed trailer. I have it at the very rear of the van and adjusted so the wind will deflect just high enough to land on top of the trailer. No deflector, 10.5 MPG with deflector 13MPG and I drive it like I stole it!
I assure everyone that his data would show a much better result if he was towing with a van, or had a topper on the pickup.
This is a great video. This was the first one that came up. I am hauling my bumper pull trailer in the wind is killing me right now. I needed some real data to determine if I should buy one of these things. It turns out that wind deflector only increases that negative void space between the truck cab in the trailer front and that is where that pressure drop occurs and increases the drag. I would imagine if you had a truck bed camper that may be the wind deflector might be helpful at that point
Yes, the toppers that slope up to the back would probably save me a couple MPG. And then to go to the extreme, put this thing I test at the back of it. That would really help IMO. I actually got better mileage with the damn thing setting flap.
You're open truck bed will reduce your fuel economy too. A cover or a cap would be a better place to put you're money.
Thanks for the info. I have been wondering about the same deflector. I have a 2013 3500 Cummins and a 2019 Rockwood Ultra lite 2304DS. I'm getting the same average mpg (without) as you were getting. You saved me some $$$.
I think your conclusions are spot on. The bugs tell the story. I tow a fifth wheel and the deflector keeps the bugs off. Next summer I'll use your methods to test my setup for mpg.
I'd love to know how it works with a fiver.
Like you said, might work with a bed cap, pretty sure it was too far away from the camper to achieve its intended effect, as always, thanks for helping the rest of us out here
there's an invisible line between the top of the cabin and the top of the tailgate. you can mess with tailgate deflectors to change properties but, without a wind tunnel, you're operating blind.
same thing with the camper attached. you would need access to a wind tunnel in order to know if what you were doing was right.
seeing as wind tunnels aren't practical for the layman, the best thing to do is nothing at all. drive slower and steady... don't use your brakes and save your money for keeping the vehicle properly maintained.
thanks for sharing though. this was interesting and a good conversation point.
I have an aeroshield from Australia. Mounted on my camper shell at the rear of my truck. I get 2 mph boost on flat roads but the real advantage is the stability of the trailer and the better control.
I need a camper shell
Looks like you saved me a bunch of money I have thought about getting one.
You are still the man Mr. Marion!!! Thanks a million for the money saving tip.
Removing the tailgate might save more $ than adding a roof mount wind deflector. I used to run an '80's K20 wo the tailgate. More aero. More visual. Less weight.
I am going to try a 4x8 sheet of plywood in the bed resting on about a 45 degree angle and see if it disrupts the negative air pressure. Next I was thinking that air deflectors right behind the cab, mounted in the bed to direct airflow into the negative air void might help. In the spring, I will definitely be trying things to reduce the negative air void. I get about 12mpg with my RAM 2500, Cummings diesel when pulling my Rockwood ROO. Without the ROO, I get about 23-24 mpg on the interstate at 65mph. I always drive 5mph below the speed limit in the right lane so everyone else has to pass me and I can just relax.
I've been thing about a sheet of plywood from the back top of the cab pointed at the top of my camper
Great info from a fellow Cajun and Ram 2500 owner. Greetings from Calcasieu Parish.
I would love to see you do a test like this with a fiberglass shell like the maroon one early in your video. Thinking about buying one to add storage on my extended RV trailering.
Yes, I'm almost considering it as I feel it's got to help. In fact in the long-term it may even pay for itself.
Marion, YOU DA MAN!! Thanks for doing this. I am now exploring ways to reduce the gap between the truck cab and camper. I was wondering if placing a spoiler on the rear of my RAM 2500 bed, placed lower than the cab roof would have any impact on eliminating the negative air pressure. I intend to experiment by using a piece of plywood placed on an angle (leaning against the tailgate) in the spring once I remove my camper from winter storage. Not sure what angle to use for the plywood. Any ideas would be appreciated. If the negative air pressure (makes sense, like an airfoil) is the issue, then perhaps directing air into the negative air pressure void would reduce the drag. Just thinking. Perhaps an airfoil on rear of truck near the trailer hitch directing air from under the truck upward into the negative air pressure area would have some impact.
I think anything you can put back there is better than nothing as I'm thinking like you on disrupting the negative air flow. I can tell you, when I put my canoe on the truck racks, my mileage improves. I'm going to do a video on that when I have time to decipher the data I've captured. I think a toper that slopes up as high as possible is the best thing but they are 2200 bucks or so and makes it difficult to get in the bed, but I think that would do the trick. Maybe even add a spoiler to the top of the topper near the back. Ugly yes, ha. For testing, I've considered building a plywood air foil like the 18 wheelers use that would butt up right close to the camper and just as high just to see. I bet it would improve mileage significantly. Man would it be ugly but just interested to see the difference.
Thank You so much for that...You just made my mind up...Had I not seen the facts; it would have been very hard to believe...
It is deflecting nothing. Why didn't you say that up front? Your the BEST!
Have you thought about putting it above the tale gate? That is if you have a Tunneau cover on your truck. Just a thought since the Travel trailer is farther away then a fifth wheel.
That would be ideal, especially a cover that slops up.
Deflectors really only help on fifth wheel setups, not bumper pull because the trailer is so far back there. Unfortunately, there's not much you can do on a bumper pull set up. I'm in the same predicament, but luckily I figured that fact out ahead of time.
The angle on that thing looks pretty aggressive, I wonder if lowering it down would help. You could sight down the plane of the deflector (like checking a 2x4 for straightness) until the top edge of the front of the trailer just comes into view. I think that and taping the front edge to make a smoother transition might make this thing actually work. I remember back in the '90s I'd see pickups (usually duallies) towing trailers with those stainless wings on top that had an upswept airfoil shape.
Thanks, I tried all kinds of angles. Laying flat was the best. ha
Thanks for your trial and info. Very helpful.
Thank yo for the thorough review. I own a fifth wheel and wont consider a deflector based on your results. I know the fifth wheel sits closer to the deflector but doubt it will have any material effect on mileage.
That's what I'm thinking also. Unless you can get it as close as the 18 wheelers deflectors, it's probably going to add more drag.
It does make a difference for a5th wheel, not travel trailer
It's too far away
Have you tried one of the camper shells you mentioned at the beginning? I am towing a Rockwood Ultra Light 2304 DS which is even taller (and heavier if you are pulling a 21’) than your trailer. A friend has the Mini Light and he is getting a couple of miles a gallon better than I am.
I had a topper on a previous truck and got better fuel mileage than this one (with a much heavier longer camper) but never really compared with and without. I think it would be better with a topper.
I think the purpose for the wing is the reduce the circling turbulence gathered between tow vehicle and trailer.
A wagon would be the worst for turbulence as it creates the most vacuum and sucks the most air into the space. A wing is most effective here when being as far as possible to the rear of the tow vehicle to kick up their air enough to skip over the space. I have a wing and find it helps 95kph and up ie helps me keep the speed limit of 100kph. Without it I find there is a wall of resistance approaching 95kph.
For a ute or a sedan towing a caravan I can’t see the wing will be of benefit as there is a minimal space for turbulence and the wing is too far forward and the kicked up air would have blended back to normal air flow by the time it reaches the trailer.
Yes I think that's what's happening to me
Yes, Agree
It site way to far away from the trailer front. It creates a reverse vortex right into the pickup bed. The devices might be helpful on the top of a SUV.
You were very close ro me when you stated you were un Childress TX, , if i would of known, i would of met you and bought you Dinner
Thank you, I love that drive on 287. Old Americana. Kind of a Route 66 with all the old towns etc....
You sir are thorough. Could you do the same with a truck bed cover? Think you will find some savings.
I think I will also. I'm thinking about getting one but $2200, yikes.
@@MarionBlair
Made my own once from some exterior mdo plywood. Used that for a couple of years till I found the one I wanted used. Paint it black nobody noticed it was wood.
Do you have a bed cover? Might find that will make a positive difference. Great video as usual. Thanks.
No but I wish I had one. I've heard that they help
thankyou for all your hard work and hours of testing , Im more interested in purchasing one of these to help with trailer sway when trucks passing me , wondering if it helps with getting the trailer more stable at hwy speeds , along with air bags, shocks , 10 ply tires, weight dist hitch , which i already have, , does it help distributing drag over the camper , i have a covered bed on my f150 crew cab , towing a 5000 lb camper ? and also was thing about air tabs also
No help in stability. A sway bar on your weight distribution hitch will help a lot.
Do you think a sloping camper shell would work better? Seems to me that the air deflector needed to be closer to the RV
Yes, agree. like these is what I was thinking. altytrucks.com/tw-series/
Thank you. I recently bought a v nose cargo trailer to pull with my Yukon. Without the trailer, I get around 500 miles to a tank. With this 6x12 v nose trailer, I am getting less than 250. It is absolutely killing me on fuel as I travel for work. Any suggestions? I think if you added a cap on your truck, and put the wing on the back of the cap, it would work better. Just a guess though
Yea, that would be perfect solution. Believe it or not, I get a couple mpg better with my canoe on top. I do a video on that one day.
You should have sold it on Craig’s List, before publishing the video 😉
Nice experiment!
Ha, yea but I dont wan't to scew anyone
Ready for the next video. Keep up the good work
Even putting on a cap will slightly reduce mpgs. At least did with my last hemi Ram.
What we did learn is that aero is really a big issue. Lol, put it under the front bumper as an air dam. Or just drive right behind a semi. You’ll get 14 MPG
Off-topic but Why do you idle while you refuel? Fuel tank needs to be sealed before ignition to pump the vacuum. Ignoring that will shorten the fuel pump and high pressure pump life cycles. Not to mention the carbon buildup raise caused by the wrong ignition cycle which itself is caused by ECU trying to compensate the excess oxygen coming from the tank.
The diesel tag has a vent to atmosphere all the time doesn’t hurt anything. Maybe I just don’t follow what you’re saying.
@@MarionBlair The morale is not to run the fuel pump when the tank is open(i.e. you should turn the ignition off before refueling). The vent you mentioned is there to regulate the excess vacuum pressure inside the tank, it lets the air in not wise versa. Vent does not work when your tank is open, because there is no pressure. Pump needs a specific pressure inside the tank to work properly. Hope this helps, but if it is still somehow unclear just ignore it )
Wow, this is some great data compiled!
If you had a camper shell and put the wind deflector at the back edge, you'd see some gains.
Yes, I agree
I'd like to get a truck cap but I'll have to come up with a clever way to get that beast off by myself. I need an open bed sometimes.
Yea, same with me.
I made a home made version when I could not find anything to fit my vehicle, First attempt was beyond terrible worse mileage maybe 6 or so pulling a 28 foot travel trailer. Could not believe it., First stop I took it off the vehicle and cut it in half. Towing was better and mileage went up. So over the next few years of towing I've tweaked it to where I no longer fear getting passed by semi trucks the trailer is much more stable going down the road and mileage went up to 11 or so. The key for me was to keep on eye on the bug line on the front of the trailer, too much angle and you are pushing air over the front of the trailer too little and the bug line is too low. I focused on the bug line at the top 2 inches of the trailer give or take an inch. Now I made mine with large aluminum street signs that were being recycled. I towed with this setup on top of my Suburban for many years on different Suburbans and never had any problems. It was mounted directly into the roof rack on hinges to and cable screw tensioner to make adjustments. I've moved up to a fifth wheel and have not yet figured out how to mount it but I will try when I got some free time on my hands.
Thanks for that maybe there's hope for me yet
Did it keep the bugs off the trailer?
Nope
What kind of fuel mileage do you get pulling your trailer
There are a lot of different opinions on this. The next time you’re on the highway you’ll see that most tractor trailers have wind deflectors. Actually more than 3 million trucks have wind deflectors on the roofs or integrated in the cab design. I guess they have them because they don’t work. If it’s too far from the cab it won’t work it will hurt the mileage.
Yes, if you watched the video, that's exactly the problem. They do work but only if they are next to the trailer like the 18 wheelers. Mine had a big gap between the deflector and the trailer. I also mentioned that it may work better with a 5th wheel.
it seems that people with 5th wheels report better MPG than this guy did with this tag along. Its gotta be the distance to the RV from the deflector?
Yes, that's what I'm thinking. They sit pretty high but much seems more aerodynamic.
It’s all about the trailer profile. 25 airstream 14 mpg 18 6.7.
Yep, I'm pulling a parachute. I'm jealous
I wonder if it was set to steep and if you were going 80mph maybe it would be the break even point!
Good idea but probably won't try it, ha
I'm guessing if you are looking for some sort of improvement on mpg, you wanna find a way to add wind resistance/ aerodynamics to the giant sail you're pulling. Similar to what the big rigs are doing with their trailers.
Yes, Think a topper would be helpful, the ones that slope up real high but $2200 and hard to get stuff in and out.
@@MarionBlair Nice comparison and interesting data as well. I am not an engineer but I think this is a case of aerodynamics at play. I used to own a bumper pulled travel trailer with a front end "air dam" similar to yours (6,500lb GVWR). I pulled this trailer with a 2016 Ram 2500 crew cab pickup powered by a 6.7L Cummins diesel for 6,551 miles and used 586.2 gals of fuel (11.2 mpg). I now own a 10,000lb GVWR fifth wheel trailer, pulled by the same truck, and to-date I have pulled this rig for 19,805 miles and used 1,672.6 gals of fuel (11.8 mpg). While not a true "head to head" comparison, I think it is a partial comparison of the aerodynamics between the two different trailers.
@@paulkoehler7061 Thanks for that. I think the 5th wheel is more economical and aerodynamics is more of a factor than weight. Good info. thanks.
Thank you Sir.
Thank you. You just saved me money
Get a TSD Logistics RV Fuel card....same as an OTR Fleet card...enjoy discounted price per gallon and no need to walk in and pre-approve fuel.
Much appreciated information thanks !
Thank you, Mr. Blair. I really thought those things worked better.
I almost wonder if it is more effective for 5th wheel campers since they are much closer to the cab
me too, ha
Thanks for the info Marion! Love your movies! BTW $370+$92=$462unless I missed something. 🤷♂️
Oops
I wonder how well air tabs vortex generators work.
I would like to know myself. I've heard they work well.
Gooseneck would be different, i would assume
I think so also
Your air deflector is too far from the trailer. I have a short bed truck with a sliding hitch. My wind deflector is 2 feet from the front cap of the trailer. I get 1.25 average mpg increase at highway speed 65-70 mph. I have checked this using cruise control and my trucks dash mpg instant fuel data on 7-10 mile runs with and without deflector. Read the information that came with the deflector it must be placed close to the trailer to get any benefit.
Love your videos, plus your funny.
Great info 👍
Hahaha, you were creating more downforce for cornering.
😎✅👍
Live and learn.
Makes sense. All it's doing is making the truck less aerodynamic.
Your gain is with new subs
Get a raised camper shell from Leer.
way too big a gap! add a shell to the bed and mount it to the rear of the camper shell.
Yes sir, that's my conclusion also.
Thanks
No problem
Smart man !
No, an idiot but thank you. Ha
$2.30 a gallon sounds amazing right now 😅
And NEVER fill up at loves again. I know you love your truck, but you don’t understand their subgrade fuel
I dont like that you have to go inside and put a fixed amount on your credit car and then they credit you back the difference.
In fact that type of wind reflector is a. Failure.
The song goes - Dum DA dum dum dum.b.... You ,not the deflector. You are not supposed to have it 15 feet away. Putting it on the cab of the truck? Hello? No. dub. You ned a camper shell or an suv so it sits at back of vehicle near, NEAR, the trailer. You have it so wrong, of course it did not work. Maybe try it on the hood next time, it might do better....
Go back and re-do from start, the right way.
How much does your camper weigh?
5000
@@MarionBlair Thank you