replacing spoiler on rpod 179
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Forum Name: Podmods, Maintenance, Tips and Tricks
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URL: http://www.rpod-owners.com/forum_posts.asp?TID=13140
Printed Date: 05 May 2024 at 3:04pm
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Topic: replacing spoiler on rpod 179
Posted By: garyd
Subject: replacing spoiler on rpod 179
Date Posted: 27 Aug 2019 at 5:58pm
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has anyone completely removed the plastic spoiler on the rpod and replaced it with a better solution? I was thinking of taking the whole thing off, re-gelcoating all of the screw holes, waterproofing the wire exit hole somehow, and making some type of alumium bracket to hold an 18" led strip light. THis way I could easily waterproof the aluminum bracket. Im interested in seeing if anyone else has done something similar. ------------- gary |
Replies:
Posted By: podwerkz
Date Posted: 27 Aug 2019 at 9:20pm
Sounds like a good idea...it might 'spoil' the looks tho....(see what I did there?) ------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 28 Aug 2019 at 4:32am
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I have a similar thought, I would do it to clear the area for a solar installation, and would attach the light strip to the back of the solar module instead of the roof. I see no reason why it wouldn't work. Might run the wires through a cord connector while you're at it. Just be aware that that spoiler probably isn't just for looks, it likely does reduce drag on the trailer somewhat. The steep curve on the back of rpods is not a good aerodynamic feature, the spoiler directs some of the airflow up and away from the body at that point which ought to reduce drag. I notice that the new rPods have a more aggressive spoiler design, I wounder if that is purely intended as a cosmetic change or if FR is trying to improve the aerodynamics. Anybody know? ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: podwerkz
Date Posted: 28 Aug 2019 at 10:03am
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I have a different opinion about that spoiler, I believe it IS for looks, and a handy place for the factory to mount some clearance lights. I am 99% sure that Forest River did ZERO wind tunnel testing on these r-pods. The airflow behind the A/C unit, the vent cover, and the TV antenna create a 'dirty' airflow and completely negate any possible benefit that spoiler might have. And even if it had some hope of reducing drag, I doubt that benefit would be enough to be measured. You might recover some actual mpg benefit by sticking on some AirTab$...maybe! ------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 28 Aug 2019 at 12:24pm
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All I can say is that there is a similar aerodynamic detail on my Prius and its not there for looks or because Toyota didn't do any testing. It actually partially blocks the rear visibility. That car is their technology showpiece, they go to great lengths to achieve the highest possible fuel economy. So spoilers do reduce drag if done properly. Whether in the case of the rPod it is cosmetic or completely negated by other features we just don't know. It is interesting that FR has made it bigger now. Did they do that because they think that enhances cosmetics or because they believe it does a better job at reducing drag? In the end its all opinion unless someone can either get some clear answers from FR or does some actual testing, which does not have to be done in a wind tunnel. Coast down tests can work also. No thanks on the funky airtabs.  ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: ArthroPod
Date Posted: 28 Aug 2019 at 12:55pm
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You might be interested in a post on flows on various configurations with the r pod under r pod air flow in rpod nation forum. It was posted a few years ago. Sorry couldn't get the link here. ------------- 177 toad with Ford 150 |
Posted By: furpod
Date Posted: 28 Aug 2019 at 12:58pm
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A first generation owner did modeling of the airflow, he was a fluid dynamics engineer. The spoiler did nothing but worsen the flow. It was actually an afterthought, and 1st generation Pods had to be retrofitted with it, because they had no clearance lights at the top, and FR lost a little battle with the DOT about the width of the trailer and such requirements.. couple of threads about the spoiler and the light/DOT issues in the archives.. Here is a picture from the very first Kentucky minimini rally... circa 2012 at Green River State Park. (for those in the know the 2nd gen 181G is Travis the owner of the FB group) Note the 2 rings pods with no spoiler, no clearance lights and no fender lights.. https://postimages.org/">
 Our very first week out, Aug of 2011.. Again note no spoiler, lights etc. https://postimages.org/">  ------------- |
Posted By: podwerkz
Date Posted: 28 Aug 2019 at 1:45pm
That is my point....there is nothing about the spoiler on the r-pod that is done 'properly' (aerodynamically speaking)......so the OP should not worry about it at all. He should feel free to modify as he sees fit...I look forward to pictures of the final result.  ------------- r･pod 171 gone but not forgotten! |
Posted By: podwerkz
Date Posted: 28 Aug 2019 at 1:47pm
Such a clean, uncluttered look.  ------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 28 Aug 2019 at 2:30pm
You don't have data to support that statement, so its your opinion, Nor do I. Whether the spoiler does anything or not, certainly garyd can to whatever he wants, its his trailer. No one ever said otherwise.
------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: GlueGuy
Date Posted: 28 Aug 2019 at 5:56pm
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I have seen Youtube videos demonstrating that the spoiler does break the vacuum bubble at the back of an R-pod. That is the alleged intent is my inference. Any square-back TT will have a giant vacuum bubble that will alternately build and collapse. The point of the spoiler is to induce the airstream to tumble, which is supposed to collapse the bubble. Key word in the last sentence is "supposed". Unless someone employs a wind tunnel or something, that's pretty much all we have to go on. ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: offgrid
Date Posted: 29 Aug 2019 at 4:14am
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When I do my solar installation, I'll try to get some data. I''ll start with some coast down test runs with the spoiler on there, then some without, and see if there is any measurable difference at all. I want the initial data anyway to see what effect the solar array has. But first we have hurricane season to get through....  ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: Tibof
Date Posted: 29 Aug 2019 at 5:30pm
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It is my understanding that the spoiler is there for the lights it contains, as required by NTSB. IIRC, early Pods didn't have it. Showed up in 2014-15 I believe. I have removed it and out of necessity replaced it with a new one. The problem was what the dealer called "the notorious leak issue." No help at all from Forest River (it was two years old) or the dealer. FR sold me a new spoiler at full freight. The old one was too badly warped to reuse. Using my own approach to sealing the thing, it has been entirely successful. I've described the details on another post in this forum. ------------- 2015 Pod Hood River Edition 2012 Tacoma Crew Cab 4 Liter |
Posted By: podwerkz
Date Posted: 29 Aug 2019 at 6:27pm
In my post #4, that's what I said, it's my OPINION, which means: no, I don't have supporting data in this case. Quoting myself here:
So yeah, its an opinion, but it is an opinion based on some experience and knowledge gained over the years, not just a random wild guess. At any rate, if a person had a way to raise and lower that spoiler with the push of a button, a simple device like the scangauge hooked up to the tow vehicle OBD port, and reading out instantaneous horsepower, might provide some insight to the effect the spoiler has...I'm betting it slightly increases overall drag. (yes, that's an opinion!)  ------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 30 Aug 2019 at 7:14am
I was referring to THIS post when I pointed out that it was ALSO an opinion. In any case, I don't think we are having any significant disagreement, bottom line is that we really just don't know.  There are 3 conventional ways to evaluate drag on a vehicle: cfd modelling wind tunnel testing coast down testing Wind tunnel testing is crazy expensive. I had some done once on a solar array roof mount system and it was well over $100K. You've just added a interesting 4th option. Rather than a button to run it up and down, why not make a few runs, get the average hp data, remove the spoiler, and run another set of tests? Like with coast down testing you'd need to have a nice flat piece of road, no wind, and consistent temperature and humidity. But you wouldn't need to hold up traffic while coasting. There are now some free personal use cfd software packages available, I'm thinking about downloading one and trying it out. Once the model is set up it would be possible to try out different aero details and see what effect they have. It would be good geeky rainy day fun if nothing else. These are interesting but not really very enlightening, other than showing that you don't want a low mounted spoiler. https://www.youtube.com/results?search_query=rpod+airflow - https://www.youtube.com/results?search_query=rpod+airflow furpod, are there any links to that aerodynamics work you mentioned that you know of? ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: GlueGuy
Date Posted: 30 Aug 2019 at 11:19am
------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: offgrid
Date Posted: 30 Aug 2019 at 5:12pm
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GlueGuy, thanks. Looks like those are the same ones I had found, I was wondering if there was something else that furpod was referring to in his post? ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: furpod
Date Posted: 30 Aug 2019 at 7:42pm
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There was another guy who did some modeling also.. But I don't know where it was hosted, though I do know it wasn't you tube. I think it was a nasa server actually. It was in '11 I think when I saw it. I do not remember the guys name/handle, he traded to a vintage Shasta not long after he posted up his results. When the spoiler first appeared there was some serious arguments about the thing, it's purpose, and it's effectiveness at air flow management. At the time we had owners who HAD been stopped and ticketed for not having proper clearance lighting, as delivered from the factory. EDIT: also, somewhere in the way back of the site.. there was a guy who did in fact experiment with the "Air Tabs". He put hundreds of them on his pod. Claimed he saw a 15% or so increase in MPG.. Looked like crap though.. LOL
------------- |
Posted By: offgrid
Date Posted: 31 Aug 2019 at 5:46am
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Thanks furpod, It's unbelievable that FR would release a product without he required clearance lighting. But, it happened... I found this post by Tidalwave4455 from 2012, was he the guy you're thinking of? "The final aerodynamic simulations I ran were putting spoilers on the TV. I placed a rooftop spoiler midway on the TV and then at the rear...I also changed the angle of attack. There was only minor variations in turbulence. Again the deciding factor was the open gap between the TV and the Pod roof. There really is no way to smooth the airflow between the TV and the Pod because of the curved frontal roof of the Pod. That long gap really causes a lot of turbulence and pressure fluctuations. It seems that you can gain 2+ mpg if your trailer has a rectangular 'breadbox' shape. The roofline helps eliminate that open turbulent gap always present in the Pod." That is a little surprising as the curved front shape is generally thought to improve aerodynamics, but maybe only if there isn't another vehicle in front of the trailer creating turbulence. If Tidalwave4455 is correct then I would think that a large spoiler like the Purpleline Aeroplus on the rear of an SUV tow vehicle ought to help more than anything. If not and a box on wheels is really better aerodynamically and provides more useable internal space then what is the point of the rPod or any of the teardrop trailers' shapes? When I looked for the airtab guy I didn't find anyone you actually did it but I did find this response from Airtab to a question about where to put them. Looks like he was looking at an original first gen trailer. I think I'll call FR next week and see what their reasons were for the more aggressive spoiler they have now. "The Rpod trailer has a particularly evil fastback design (in side view) that much like the early Porsche 911 fastback body style, suffers from terribly high aero drag. That's because the location of flow separation on the curved roof top surface wanders forward & backward over the tail. As the rooftop's separation line wanders aft, the adverse pressure gradient builds to unsustainable levels and the flow separates, then the flow attachment line snaps forward and gets re-established. This unstable flow oscillation builds and collapses much like the current in an old ignition coil. Every time the flow separation location snaps forward it creates a huge unwanted burble of large scale turbulence that migrates back into the near wake. This unsteady flow has a periodicy that varies with vehicle speed. Porsche stopped it by inventing the Whale Tail which also gave some downforce. Today's modern VW "Bug" has a smaller lip above the rear window. The purpose it is to fix the separation point at one location (in side view) so it doesn't migrate fore-and-aft over the rear window (which creates very high drag). A side benefit is that the vehicle then becomes more stable. The little teardrop-shaped Rpod trailer badly needs a similar "lip" installed transversely across the entire rooftop - to fix the point of separation at one point. I would suggest it be located about one-foot aft of the rear of the rooftop air conditioning housing. You could place a row of Airtabs across that station on the rooftop, but the vorticity would simply help the flow remain attached further aft. Unfortunately, eventually the flow would separate farther downstream, and then the unsteady flow mechanism would once again occur. Only this time it will be worse, because the unsteady aero forces are occurring farther aft on the trailer - which might make the tail wag the dog so to speak. So don't let him use Airtabs transversely across the roof. Instead, have him mount them only on the sides - not in a straight vertical line but following the side contour. In other words, the trailing edge apex of each Airtab should be located just a couple of inches forward of the trailing edge of the side of the trailer. The line of Airtabs will be curved to mimic the side contour as viewed from the side. Much like the red painted "swoop" graphic except positioned far enough aft that the line of Airtabs will fit aft of the side window. ======================== The customer, JC, writes back in May 2012 saying this.... Mr. Latimer- again a very helpful reply, which I greatly appreciate. Forest River must have been talking to your aero guy, because they began installing a “lip” or spoiler, that goes transversely across the roof in 2012 (my unit has it) and all the units going forward. It looks exactly like what your aero guy is recommending. I’ll sketch out, my understanding of your air-tab scheme for the side of the trailer, scan and e-mail it, to make sure that I am understanding the advice. Then I can get a count together and place the order. Again thanks for your follow-up, which is both rare and appreciated."------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: furpod
Date Posted: 31 Aug 2019 at 7:36am
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Not sure which is which as far as context there.. But, yes that is one of them. And it could be the particular guy I am thinking of wasn't on THIS forum. There used to be several, maybe 5 I think. Only 3 are any kind of active now, the one at FR Owners forum, The Nation, and Here. FB has become the de facto "big dog" currently closing hard on 15,000 members.. literally hundreds of posts a day. On FB there are also several, much smaller, mostly specialty groups, like "R-Pod owners who tow with Jeep JK's", "Sunshine State R-Podders" etc etc.. I am a member in a couple of those groups, just because... As far as "why an R-Pod if it isn't aero?" I think because the shape is pleasing, and the original sizes were "just right". Sometimes, things don't have to be perfectly efficient, or the very best, at anything, to still be pleasing in people's eyes, or minds. I know a couple owners have tried the spoiler on the truck cap or rear of an SUV, I cannot recall any EUREKA!! moments being posted. I did spend some time last year visiting with a work from the camper couple who had a ginourmous fiver. Biggest thing Grand Design makes. Towing with a F450.. They had a spoiler on the truck cab that they said gave them 20% better mileage.. which was something like 12 without, 15 with.. They had scaled at just under 18K pounds for the camper.. almost 28K for the whole rig. ------------- |
Posted By: GlueGuy
Date Posted: 31 Aug 2019 at 9:23am
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IIRC, Stephenh had tried the Purpleline Aero. I don't recall whether he felt it provided any benefit or not. Kind of noodling out loud is whether a reverse spoiler would provide any benefit? Something that was actually curved downward and sitting above enough to encourage the airstream at the back of the R-pod to stay attached long enough to fill the vacuum bubble. ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: offgrid
Date Posted: 31 Aug 2019 at 11:35am
Thanks furpod, Yah, I was only being half serious there. But I do think lots of folks (myself included) think that the teardrop shaped front ought to be better aerodynamically. I'm not at this point convinced that it's not without seeing more data. The rear is another story, it clearly drops off too steep to keep the airflow attached, that needs to be 15-20 degrees tops. You can see the detaching airflow on those youtube videos. So a proper spoiler placed where the curve reaches 15-20 degrees ought to help control it. i'm wondering if the new larger rPod spoiler is an attempt to do that. I'm personally not a fan of FB. If someone is interested enough and finds something useful over there let me know. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: StephenH
Date Posted: 31 Aug 2019 at 12:07pm
I found more benefit when we had the Escape and not as much with the Frontier. This is mainly because it sat closer to the RPod on the Escape and the Frontier, even with the tonneau cover, has the 5' bed space between the AeroPlus and the hitch plus the additional distance between the hitch and front of the trailer. It still helps deflect some of the bugs though. ------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: offgrid
Date Posted: 31 Aug 2019 at 12:39pm
Kinda like a car wing sloped down rather than up? I'm not sure it it would reduce drag or not but it would produce lift at the rear of the trailer. That's a bad thing in a race car but might be good for sway reduction on a trailer. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: GlueGuy
Date Posted: 31 Aug 2019 at 12:45pm
------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: podwerkz
Date Posted: 31 Aug 2019 at 3:00pm
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I watched those airflow videos....the one with the spoiler apparently shows that spoiler down farther, and farther away from the A/C unit than I see on the roof of my r-pod. On my r-pod the spoiler is directly 'shadowed' by the A/C unit and the roof vent cover. This is what I refer to by being improperly placed to improve aerodynamics. It may be that on the longer r-pods, the spoiler sees some undisturbed air...but on mine, I am sure it does not. http://photos.app.goo.gl/fGpvgz1QqYMhFDaq9 - https://photos.app.goo.gl/fGpvgz1QqYMhFDaq9
------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 31 Aug 2019 at 5:25pm
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yah, on the smaller pods you have a pretty short deck. If you don't put the spoiler on before you get to where the roof slope exceeds 15-20 degrees the airflow will separate anyway, so the smaller pods might have a problem there. I found that software and I'm working on getting some new airflow videos now. I'm using my 179 and Highlander TV. One problem with the models in those videos is that it looks like the Reynolds number might be set too low, allowing for some laminar flow, which we don't have at the speeds and dimensions we're working with. I reset it higher to get rid of that. If anyone wants to fool around with this software, here's the link, its pretty easy to use. The hardest thing is to get a good photo uploaded. Stand way back when you take the picture. You have to use a .bmp not a .jpg and it can't be wider than 1400 pixels. To get rid of the background you can use Paint and carefully cut everything else out so its all white except the trailer and TV. Once you get the profile in you can draw in whatever aero feature you want really quickly. http://www.flowillustrator.com/ - http://www.flowillustrator.com/ ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: marwayne
Date Posted: 03 Sep 2019 at 7:21pm
https://postimg.cc/5YRbRNpd">
------------- If you want something done right, do it yourself. 2011 RP172, 2016 Tundra 5.7 Litre, Ltd. |