2004 E450 Bus Build

[seuadr]

don't know if this is the most appropriate place for a build thread, but, i'm already here so...

i have a scangauge 3 on it's way (because there are 5 or 6 inputs i should keep an eye on at least until i have more confidence in the EGR cooler health)

spent the last weekend rebuilding the rear axle - new calipers/rotors/pads and axle seals - bearings were actually in really nice condition - i don't think they've been in there long. My mechanic friend explained that it is a full floating rear (and then explained to me why that is good ) also replaced rotors and pads on the front axle, but, i had a lot of trouble bleeding and getting the system firm so i'm going to replace all of the rubber lines everywhere, the front calipers, and all new brake fluid - no reason to take any half measures with the brakes on something this heavy.

this weekend i plan on doing the line/caliper replacements. then i have some pinhole leaks in the fuel tank to deal with and i plan on going full synthetic with all oils and a water free heavy duty coolant (the biggest drawback is you have to change it out every 45,000 miles.. oh no! ) the boiling/expansion point for it is MUCH higher than a water mix, so, it should do a great job of protecting my cooling system for.. well lets face it, it'll probably take me a DECADE to put 45k miles on this as a rec vehicle!

then comes the rear design - i want to boat tail this, and, i've read through the RV threads i've seen on here a number of times - the biggest questions i have is what i want to do inside the boat tail.

on one hand, i could have it be exterior only, and i think it'd make great exterior storage - there are all KINDS of things that could fit in there, including bikes, hoses, fuels, etc.

on the other, do i knock out a portion of the back wall and make it a master suite so that we have more room in the bus?

decisions, decisions

pretty sure i want to frame it out with an aluminum skeleton and composite fiberglass/xps sandwich panels. that should be really tough, well insulated, good sound dampening and long lasting. either way i go, that'll provide a secure storage area, or a nice "bedroom" and i have a good source for the framing both from an engineering standpoint and a fabrication standpoint because my mechanic friend builds these out for all kinds of things (as well as his son now for a different shop!)

then we can tackle the aero other places - like i intend to remove the mirrors and use cameras instead (which i actually already own and use on my current travel trailer) but leave the mounting studs in place in case i get in trouble and need to "fix it or ticket" - i can remount right on the side of the road if needed.

the space between the ... forehead bump? and the windshield looks like it could use some smoothing, as well as fiberglass blisters for the cameras.

we'll be doing away with the front bus door, so, can smooth that out and part will be used for external storage (the steps are going to get locking doors) and the upper portion turned into a window and/or storage.

i've been thinking and thinking about how to do a fixed awning that i could hide away inside the frame, but, ultimately i'm not sure that juice is worth the squeeze - considering just having lower mounts for the poles and taking it completely off when traveling - i wanna add underbelly storage anyhow, so i could slip it in there somewhere.

the grill/headlamps seem pretty smooth already, so i'm not sure i wanna do much there - but the front bumper is built out quite a bit from a pretty soft rubber mounted to an aluminum plate so i think that'll be a GREAT platform for an air dam or splitter?
(not mine, but same year/model/material)


i also plan on trying to make the interior more energy efficient - probably going to insulate with a paint on vapor barrier and xps panel also considering an undercoating both for sound and protection - and because i want to add belly storage at least part of a underbelly pan - not real sure about mounting points though, because unlike the belly pan on orbywan's RV, mine floor is fiberglass and i kinda don't wanna run anything through it - and i don't have much by way of other things to attach to - just the frame rails.

where i put my tanks and underbelly storage, though, i'll probably mount something like Unistrut and threaded rod so that'll give me something solid.

just wanted to give an update since many of you have given a TON of input to me on this, so wanna keep you abreast of changes as they happen.

once it is home, i anticipate a lot more work completed, because it has it's own rear heat system i think i can get away with working on the interior in the winter, provided i can work up a "shore power" solution for it (it looks like the conditioning is actually AC powered with a large inverter behind the seat, because it has a load center that looks like a sub panel with normal breakers - but that doesn't mean it is..

[seuadr]

from this thread: HERE

i saw this recommendation on angles:

Originally Posted by aerohead

If you were only dropping from the top,your best angle would be 9-degrees.
If you'll do a 10-degree side angle boat-tailing,plus a 10-degree upswept diffuser you can exaggerate the top slope to 25-degrees.Chamfering the edges will net you the drag minimum.It will be very much like the Aero RV.On a simple 'box' form,this tail delivers a 0.0934 drag reduction (delta-35.6%).This was all tested in 1984 by S.R.Ahmed et al.You'd find it in Hucho's text.

that seems like a very reasonable taper - but, i'm not sure about the chamfer - should it just be a straight 45-deg or would a curve between them be better? (or better enough for the effort vs the 45, which would be a lot more straight forward?)

the top to side corner(s) already have a chamfer that i could taper from possibly? would look better at any rate (assuming i don't do a bad job anyhow...)

Either way i plan on mocking something up with wood and sheeting - maybe even cardboard so i'll have some practice...

[freebeard]

Disagree. 0-4 degree upsweep in the difusser.

In that area the constraint is not the airflow, it's the departure angle. IMHO side taper should be half the top taper.

[aerohead]

Originally Posted by seuadr

from this thread: HERE

i saw this recommendation on angles:



that seems like a very reasonable taper - but, i'm not sure about the chamfer - should it just be a straight 45-deg or would a curve between them be better? (or better enough for the effort vs the 45, which would be a lot more straight forward?)

the top to side corner(s) already have a chamfer that i could taper from possibly? would look better at any rate (assuming i don't do a bad job anyhow...)

Either way i plan on mocking something up with wood and sheeting - maybe even cardboard so i'll have some practice...

The General Motors 'OPTIMUM' boat tail had all-radiused edges, however, was designed specifically for a trailer van with matching upper edge radii. GM used a radius equal to 7% of the trailer box height.
Since your bus already has the softened edges, it would make sense to integrate the tail into those.
GM's tail was 20-degrees downslope, 10-degrees plan-taper, and 10-degrees diffuser.
GM's tail length was 93% of the box height.
All edges, top, sides, rear, and bottom were softened with the same radius.
In Thomas Scott Briedenbach's US Patent # 8590961, he does the same thing. He used 12-degree upper, 12-degree sides, and 9-degree lower.
On my first trailer, I ran large Schedule-40 PVC pipe through a table saw and used the inner surface as tooling to create wet-layup FRP radii. Polyvinyl alcohol and 3-coats of carnauba wax made for a clean release.
It amplifies the fabrication man-hours, but kills edge vorticity, which can be a source of relatively high drag.

[seuadr]

That is a great idea on the pvc, i was trying to figure out if i might do it with cut down rigid foam but felt like a lot of trial and error. I like that much better.

Got insurance and plate today, so now i just gotta finish the brake work and bring it home so i can have easy access for measurements.