fairing for trailer questions

[Sven7]

Looks good- get on it!

[slowmover]

Not sure that there will be a benefit with Mom's Attic (the U-Haul name for same) as turns & crosswinds will take their toll. The increase in sail area is the concern. I'm happy to be wrong (not my project), but it's my first reaction to trying to smooth out the transition from one vehicle to another in this way.

Second concern is the occasional off-camber hitch up where the vehicles are at several "wrong" angles to each other.

.

[KamperBob]

Skyking, since you are building a 5er from scratch I'd suggest scaling the template for trailer height. With only 12+ inches above the truck cab I'm wondering how comfortable the loft will be. But as slowmover says it's not my project. From there I would slide the template for convex transition after the windshield. This is hard to put into words...

[skyking]

that 12~14" inches above the cab is a cab mounted rounded fairing idea, to smooth the transition from the sloping windshield to the horizontal section. Nothing will go in there and it is fixed to the truck itself.
sorry if you guys misunderstood.
It was an attempt to slow down that air a bit. As Phil has mentioned from time to time, the surface velocity above a blocky cab is 90 MPH at 60 MPH forward speed. The whole purpose is to get that speed back down to 60 as it leaves the rig.
If I can mitigate that acceleration just a bit it will help.
As far as the sail area, the crosswind pulls you around, not pushes, and it pulls the hardest on a square edge.
That bump fairing will not add to frontal area of the combination, but it will have really gradual radiuses on the front and sides.

[slowmover]

Thanks for the clarification, skyking.

As I was going to bed last night the Weather Hazard radio went off (again) and it reminded me of the storm we had on May 10th with sustained 60-mph winds. So the third concern in changing the trailer exterior envelope is how well it handles winds when parked (lift & tilt).

Strange weather (unseasonable or flat unusual) is no longer to be ignored. An uncoupled 5'er has a large area well above ground level for winds to play with.

Past the above (this, and other posts) sounds like the reason for the "extension" would play well.

.

[skyking]

I'll have less up in the wind with the roof down than your airstream, @ 87" tall. Roof up, 108", about the same height. Much less weight though. I may have to lower lid and spend a night on the sofa in extreme weather.

[KamperBob]

Skyking, could you post something visual on this thread to help me get my head around your project?

[aerohead]

Originally Posted by slowmover

Thanks for the clarification, skyking.

As I was going to bed last night the Weather Hazard radio went off (again) and it reminded me of the storm we had on May 10th with sustained 60-mph winds. So the third concern in changing the trailer exterior envelope is how well it handles winds when parked (lift & tilt).

Strange weather (unseasonable or flat unusual) is no longer to be ignored. An uncoupled 5'er has a large area well above ground level for winds to play with.

Past the above (this, and other posts) sounds like the reason for the "extension" would play well.

.

The wind issue is a big concern.
Not too long ago,Schneider Trucking's Dallas,TX hub was struck by a tornado which sent 13,500-lb trailers flying hundreds of feet.A weather chopper was broadcasting live feed.
What was weird,is that after the twister passed,they scanned Schneider's entire parking area,and none of the tanker trucks had budged,even though they were adjacent to tractors with their hoods sucked off,and trailers which had flown away.
The Airstream/Argossy/Burro/Casita trailers with generous radii all around should be the most immune to wind.Of course there's a point where anything will become airborne.
I like to think that the radii skyking has planned for the 5'er will mitigate some of the hazard we can see on You-Tube,where caravan trailers are falling over like a drunk on a bender,out on the highway.
To me,that footage was like a salesman for Haulmark,Featherlite,and Wells Cargo.Anything with 'soft' sides.
And from some of the drag tables over in the boat-tailed -trailer thread,you can see that this rounding drops the Cd quite nicely.

[skyking]

I really like how it mitigates some of those pesky crosswind effects :thumbsup:

[aerohead]

Originally Posted by skyking

I really like how it mitigates some of those pesky crosswind effects :thumbsup:

No kidding,Gilkison recently pulled his 22-ft APEX out to western New Mexico to observe the total annular solar eclipse.He had a 40-mph crosswind on I-40 and was afraid to attempt pulling at anything over 45 mph.His mpg dropped to 10.6 mpg,from an ave.12.5.He said it was pretty freaky.
My Karmann Ghia will change lanes when emerging from under an overpass in similar conditions.
Orbywan's Ford motorhome looks like a VW 1-liter car in comparison to the APEX.I think the 5'r will be friendly on the road.Diesel pumps will hate it!