UK RV streamline a brick challenge. (Aero + other mods)

[guyd]

Hi,

set myself a challenge of improving the mpg of a 33' long 8' wide 11' high brick, aka my coach based motorhome / RV

last run had us getting 11.5mpg at a pretty constant 65mph on a motorway across england. It was late, I was tired, and I wanted to get home as soon as possible.

The next day, I started looking for ways to improve mpg - and for forums to help me. This one came up time and again, so I joined.

Starting with some simple bits

1) rear wheel covers
2) Tyre pressure to max sidewall (well, 105psi is all my compressor will do)
3) mirrors delete, camera replacement
4) Cold air intake - its a turbo diesel 5.8litre straight six


heres some pics of the delete mirrors. Note the steampunk use of copper pipe to house the ebay special mini cameras. The idea is that if I clip something, the pipe will swivel round on the munson ring holder.

Cold air intake - see how the air intake is right in front of the radiators? The air comes in from under the shelf the maglite is on, and is directed up to the radiators. However - in sunny climates, there is so much air coming in, that the blower for the cabin can only get hot air (the intake for this is 12" above the top of the rads). My only solution to this was to remove the front bonnet. The next, better, solution will be to separate the air for the rads from the air for the cabin. I will have to add a second blower for the rear of the camper as there isnt enough heat from just the cab blowers.

See the huge gap above the rads? that stuff you can see behind it - especially the silver blanket, is the engine. The engine sits between the driver and the passenger, so all that hot air, or cold air, depending on the weather, is being blown into the space around the engine. I think Ill block it off somehow.
Do I:-
a) 'join' the top of the rad to the top of the grille?
b) just block off where I have written 8"
if I do A, then theres no air for the blowers - that could be resolved with another grille though.
Need to do a grille block, but it has to be on a wire of some sort, as getting in and out is a pain.

[guyd]

Dumb q - how do I link to pics in another thread? - I dont want to double upload the same pics.

[ChazInMT]

Simplest way is to right click in the other thread on the picture, select properties, copy the url for the pic there, then come here and click on the Insert Image icon that looks like a little mountain with a yellow sky up there, hit paste, Bada Bing....thats it.

[guyd]

ah - ie chuck {IMG} tags round the url then. some forums dont support that unless its a jpg etc.

right - heres the wheel covers, and the original mirrors for comparison.

[MetroMPG]

(Thread relocated on request).

And... I'm subscribed.

So! We all know where the biggest single gain is to be found - dealing with the rear of the vehicle, aerodynamically. How far away is that on your list? Are you planning or even allowed to do it where you live?

[guyd]

as far as I know there is no practical length limit to a motorhome - bar percentage of overhang, which im nowhere near.

Plastic continuous hinge has been ordered, sheets of ally and rivets in the garage. Just how to attach it to the back is a differnt matter. I have the original blueprints for the vehicle - including the description of the framework.

on this scale, would it matter if the boat tail started a few inches inboard of the vehicle? the framework might be (I have yet to look) inboard, as the corner is just relativly thin fibreglass that offers no real structural support.

Boat tails are 15 degrees arnt they?

[MetroMPG]

Have you seen this thread?

http://ecomodder.com/forum/showthrea...d-e-18151.html

Optimal Boat tails are more organic (ie. curvature) than a single straight angle.

Starting the tail inboard from the edges a few inches will work, but isn't optimal -- you'll lose some energy to trapped vortices/turbulence in the "gap" between the RV and where flow re-attaches to the tail.

[guyd]

yeah - read all that. amazed at the lack of change of the under body streamilining.

Anyone know if the top is really important with a boat tail in my config? considering the really rough surface with a pile of vents and three skylights....

[freebeard]

Here's a free idea:


You're welcome.

[btracing]

Wow, nice RV you have there to ecomod! I would try to make an airdam and pannel the underside. I think that's a spot where also a lot can be won. The wheelcovers are nice and ofcourse the Kammbach .

My major worry though, YOUR MIRRORS! You have huge blindspots without mirrors, I would say very very dangerous. Maybe some small round (concave?) mirrors can be put on just for safety? But it could also be that your camera systeam will be very good. With both a wide angle camera for the maximum viewangle and a normal camera for a more detailed view (tele).