r-pod gas mileage fix
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Category: R-pod Discussion Forums
Forum Name: Podmods, Maintenance, Tips and Tricks
Forum Discription: Ask maintenance questions, share your podmods (modifications) and helpful tips
URL: http://www.rpod-owners.com/forum_posts.asp?TID=1558
Printed Date: 03 May 2024 at 2:48pm
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Topic: r-pod gas mileage fix
Posted By: semiretired
Subject: r-pod gas mileage fix
Date Posted: 17 Jan 2011 at 9:22am
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I am a new member who has not bought a r-pod yet. Looking over everybody likes and dislikes poor gas mileage towing seems to be the big complaint. Has anybody looked into the wind deflector kits that semi trucks use. Their are kits for mounting on the roof of a pick up or suv etc. What I have read the closest to the front of the trailer the better.In my case I have a fiberglass cap and it could be mounted to the rear of the camper cap. Has any one looked into this option. These deflectors are adjustable changing the angle for best results of air flow. This deflector is suppose to give about 2 mpg increase. Cost about $350 Any input would be appreciated...thank you |
Replies:
Posted By: techntrek
Date Posted: 17 Jan 2011 at 6:35pm
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Welcome. You have touched on the biggest discussion we've had around here. If you haven't read through it yet, you should look at this thread: http://www.rpod-owners.com/forum_posts.asp?TID=1347&title=gas-mileage Air dams have been mentioned as a possible fix, but I don't think anyone has done a before-after test to see if they help. One of the mods here found a slight increase in mpg when he put his kayaks on the roof of his tow vehicle in a V formation. ------------- Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ http://www.rpod-owners.com/forum_posts.asp?TID=1723 - Pod instruction manual 
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Posted By: rpodcamper.com
Date Posted: 17 Jan 2011 at 9:49pm
| I have played around with different tow vehicles and combinations of items. i did find an increase when the kayaks were in a v shape on the top of my trail blazer. I'm now pulling with a dodge ram 1500 and looking to put a cap on it and the kayaks above it. Will let you know what I Find out. I don't think an air dam will do much and also if you look at the cost versus the savings you see you will have to tow a bunch of miles before the break even point |
Posted By: Goose
Date Posted: 18 Jan 2011 at 12:33am
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After reading up on trailer aerodynamics, one of the best ideas was to lower the front air dam under the front of the TV and then add side skirts along the sides to keep the air from flowing uder the TV. If you added side skirts along the frame of the POD from the hitch all the way to the back, you would force alot of air around the trailer. So much for axle risers though. The air conditioner on the roof creates some drag as I would have to believe that the spare tire set the way that it is creates some drag also. It was said that without the front air dam or side skirts keeping the ground clearance of the TV and the trailer the same would help. Keep the under side as smooth as possible. The greatest amount of drag comes from the turbulance between the TV and the trailer. If we could make the TV and trailer seamless that would end a lot of the problems.
Like rpodcamper says, those that only travel 300 to 500 miles a year the cost would not justify the savings. You would have to do the 2 to 3 thousand cross country trips. Goose  ------------- Mother Goose's Caboose..2011 RP171..07 Grand Cherokee 
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Posted By: TIDALWAVE
Date Posted: 20 Jan 2011 at 9:05am
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When I ran some airflow simulations on the R-Pod and a couple of tow vehicles (see Fall, 2010 Forum) , not only did the separation distance between the Pod and the TV make a noticeable difference but also the disruption of the airflow caused by the 'relatively' large AC on the roof! I ran several other simulations using a different 'bread-box' profile and found more disruption caused by the AC than using a tear-drop profile versus 'an old fashion' squared off design. Some conclusions: the TV-RPod gap caused a noticeable disruption even when an airfoil was installed on the TVs roof (the Pod's curved front roof increased the gap compared to a squared off front section); the R-Pod's tear-drop profile did nearly nothing increasing airflow efficiency; the AC on the roof of the Pod made the most noticeable change in airflow (airfoils on the Pod's rear were mainly ineffective). ------------- TIDALWAVE |
Posted By: Goose
Date Posted: 20 Jan 2011 at 10:45am
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For the air conditioner on the roof of the POD I have thought of making an air sheild for the front and a boat tail for the rear, using fiberglass with foam to create the shape.
In the front I thought that a cover over the propane tank and battery following the v of the frame back to the front wall and angling upward slightly might help to reduce the turbulance between the TV and the POD. Keep it light.
I keep telling myself to get out to the garage and make a wind tunnel and scale models to test ideas on increasing efficency, but it has been to cold. Goose ------------- Mother Goose's Caboose..2011 RP171..07 Grand Cherokee
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Posted By: Goose
Date Posted: 20 Jan 2011 at 11:15am
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TIDALWAVE, I went back and looked at your youtube sims. I had not seen those before and what got me was the amount of air disturbance that starts at the front of the TV and flows under it all the way to the rear of the POD. I am highly impressed with ability to do that, but I have to wonder what the difference would be if you added an air dam at the front of the TV along with side skirts. It looks like that may help a lot stop some of the drag. Goose ------------- Mother Goose's Caboose..2011 RP171..07 Grand Cherokee
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Posted By: blissful
Date Posted: 06 Jun 2011 at 7:14pm
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If you keep the speed under 50mph(which most people prefer not to bepoking along) it will increase your mileage...I own a 2006 Hyundai Tuscon and get 15mpg by keeping my speed around 40mph.
Blissful
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Posted By: Outbound
Date Posted: 06 Jun 2011 at 10:45pm
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The leading edge isn't nearly the problem that the trailing edge is. Have a look at the http://www.youtube.com/user/outboundcamper - airflow simulations I did when I bought my R-POD. A spoiler will be far more effective than a deflector. Look around at the aftermarket manufacturers sites and you'll see that realistically, deflectors, spoilers or other approaches may increase gas mileage by 2-10%. This will take 10 MPG to an optimistic 11 MPG. This means you'd save 4.5 gallons of gas on a 500 mile round trip. And lets say that you travel 5,000 miles per year with your R-POD. At 11 MPG vs 10 MPG, you'd save 45.5 gallons of gas. At $4/gal, that would be $182. How much are you willing to spend on deflectors or spoilers to achieve that savings? Keeping your tires properly inflated, your trailer properly levelled, your speed reasonable (55 MPH) and dramatically reducing jackrabbit starts are by far the most effective things you can do. They're free, too. With conservative driving on relatively level roads, you may achieve 13-13.5 MPG. At 13 MPG, that 5,000 mile annual distance would save you 115 gallons - $460 at $4/gal. And time-wise? That 500-mile round trip would take 1 hour and 24 minutes longer at 55 MPH as opposed to 65 MPH. Forty-two extra minutes each way. ------------- Craig :: 2009 RP171 towed by a 2017 F150 |
Posted By: Snowbound
Date Posted: 07 Jun 2011 at 2:11pm
Thanks Outbound. We appreciate you doing all the math! ------------- Tom and Bette in our 177 "The Gastropod" |
Posted By: Outbound
Date Posted: 07 Jun 2011 at 2:26pm
LOL.. I'm a statistician. Math is what I do for living  I'd just hate to see someone spend hundreds or thousands of dollars on spoilers or deflectors to save a few bucks in gas. It was the same thing two years ago when people were trading in 1 or 2 year old SUVs on more economical cars. Sure, they'd save $50-$100 a month in gas, but they lost $5-$8 thousand on the trade-in. And, if they'd just drive a little bit smarter, they'd save $20-$40/month on gas on their current car. ------------- Craig :: 2009 RP171 towed by a 2017 F150 |
Posted By: Hodge-PODge
Date Posted: 07 Jun 2011 at 4:07pm
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Hmmm, you're a statistician. Ever helped with statistical tests for the quantitative analysis part of a dissertation? Not that I mean to get the forum so off-topic! ------------- 2011 RP 177, the Hodge-PODge 2011 Mercedes ML350 "A man travels the world over in search of what he needs, and returns home to find it." |
Posted By: Outbound
Date Posted: 07 Jun 2011 at 7:05pm
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Quantitative analysis? Not in a very long time. ------------- Craig :: 2009 RP171 towed by a 2017 F150 |
Posted By: Hodge-PODge
Date Posted: 07 Jun 2011 at 7:36pm
Well, I wasn't really expecting you to, but it was worth asking. Seriously though, I am soon going to have to find an "expert" in the field, seeing as my dissertation is a quantitative study and statistical tests are not my strong suit.
But getting on back to the topic of gas mileage . . . . . you had some good statistics there!  ------------- 2011 RP 177, the Hodge-PODge 2011 Mercedes ML350 "A man travels the world over in search of what he needs, and returns home to find it." |
Posted By: TIDALWAVE
Date Posted: 07 Jun 2011 at 7:43pm
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One of the problems with 'spoilers' installed on the TV is still the separation gap between the TV and the pod. Several members have mentioned the spoilers, etc. seen on 18-wheelers. If you take a good look, the 'spoilers' are not only installed on top of the cab to control the air flow over the top of the trailer...but also 'side spoilers' extend back toward the trailer also. I am thinking about doing some more airflow sims, using the shape of a fifth-wheeler Casitas attached to the bed of a pickup. This combo should be closer to the optimum than towing a Pod. I will try to post the results ASAP. Unfortunately, this type of combination won't be of any consolation to those of us who haul a Pod. ------------- TIDALWAVE |