The P5: What Would You Change?

[floydv]

Custom canvas Elio cover, check!

Maybe two styles - one that covers the entire vehicle including the outriggers for storage, one that just covers the fuselag...uh, body. That'd be handy at work when you're just concerned about protecting the interior from sun damage, and would like something that installs/removes quickly.

I know this is a family friendly forum and this may (understandably) get deleted, but wouldn't a fuselage-only cover resemble a certain type of prophylactic at a certain angle?

 

[Muzhik]

The ribs are mounted perpendicular to the sliding rails. Up front, the rails are about 20" apart, but at the back they are about 14" apart because Elio has a tapered roofline. As the ribs up front slide to the back, they will need to compress or flex in order to fit into the 14" space at the back.

Nevermind, I give up. Somebody else can figure out the soft top geometry.

My youngest daughter is getting her degree in both math and physics, including (but not limited to) N-space geometry. Maybe I can call her up and get her to jump in on the conversation.

Time and Space may have a warp and woof; if so, I just want to rip off the selvage and true up the fabric so things finally start turning out right.

 

[NSTG8R]

I know this is a family friendly forum and this may (understandably) get deleted, but wouldn't a fuselage-only cover resemble a certain type of prophylactic at a certain angle?
View attachment 8515

I was thinking more of an upside down version of one of these...that's "reusable". Haven't had to worry about the style you're eluding to in over 30 years.

 

[outsydthebox]

The ribs are mounted perpendicular to the sliding rails. Up front, the rails are about 20" apart, but at the back they are about 14" apart because Elio has a tapered roofline. As the ribs up front slide to the back, they will need to compress or flex in order to fit into the 14" space at the back.

Nevermind, I give up. Somebody else can figure out the soft top geometry.

Hey Seth, I agree with Rucrazy, don't give up....I know you won't anyway...This mental challenge will keep "poking" you. Start at the end and work "backwards." But don't ignore the "physical laws"...as we currently understand them.

DOG-GONE-it! I'm not gonna be able to stop thinking about it.

 

[outsydthebox]

I still think that designing snap-in roof panels is a Mich better way to go. You could just unlatch them from inside and pop them out.v two panels would be probably smaller that 12" X 12" each and easy to store. If the roof was made of simple to swap out panels, you could get a couple of clear panels and mix and match... front half solid, rear, clear,... front open, rear solid... both open.... both clear... both solid. Thinking about it, it would be VERY simple and inexpensive.

I really think you are right. A tappered-folding soft top sounds cool but it defies the "K.I.S.S." principle. Removable panels would be more aerodynamic, both closed and open. More secure. And having separate (front and rear) panels makes them easier to store, too. IIRC, in pics of the Elio "tube" frame, there is a cross tube in the vicinity of the rear edge of the door. This could be (non removable) "roof" between the hatches, allowing the interior & headliner to cover that part of the frame.

But, a tapered folding Rag Top would be SOOO COOOOL!...along with Red wheels and wide White Walls...Very "retro"

 

[outsydthebox]

I was thinking more of an upside down version of one of these...that's "reusable". Haven't had to worry about the style you're eluding to in over 30 years.

View attachment 8517

YES! that's a great idea. Like the "hatch cover" on a Kayak! Some covers are made from Neoprene. It stretches quite a bit, it's waterproof, stays taut and has pretty good insulative properties.

 

[NSTG8R]

YES! that's a great idea. Like the "hatch cover" on a Kayak! Some covers are made from Neoprene. It stretches quite a bit, it's waterproof, stays taut and has pretty good insulative properties.

As long as it's waterproof, lightweight, and UV resistant (elastic/bungie around the bottom would make for a super-simple install/removal). I'll defer to the canvas material experts on which type would work best.

 

[Coss]

Seth I know what you're talking about with the snap on panels but you're still going to need some kind of solid piece for the front header.
Otherwise it will whistle and "buzz" (or flutter) at speed.
Aero on roof panels is crazy; we fought "booming" sounds when a sunroof was open and side windows closed; rattles that we could never recreate until one time when the customer dropped off his car for another attempt, and this time we saw him take his golf clubs out of the trunk before leaving. Because of the acoustics in a car, where the heads of the clubs sat, he would hear it next to his head (we had him put covers on more of his clubs, and move them to the other side; problem solved).
So you will run into these little head scratchers once you cut that hole in the roof.
To test weather proof, you could build a mockup of a roof panel; put your cover on it, and set it outside. Make sure the lower part is away from the elements; something like a old cooler, build a curved panel for the top, and a clear, removable side to view the interior.
You've got time, and we still have a lot of weather left before summer; plus next fall; lots of time to prototype different ideas.
And I would much rather experiment on a cooler than the roof of a new toy.

 

[Lil4X]

Not sure I'd want one, but that retractable roof idea is terrific. Keep up the creative work!

For me, I would prefer a moonroof - even though the tandem-seater's roof is pretty narrow. A tilt-and-slide moonroof has a couple of features I've found very valuable here in the Texas tropics:

Pros:

1. Provides great ventilation of a hot cabin in July for the first few blocks until the AC catches up. Those swing-out windows do the same, but as designed without remote operation, require a stop to get out and close. Normally, this only happens in a driving rain.
   
2. You can adjust the tilt opening for relatively quiet ventilation in any season.
   
3. On a winter day it provides a good deal of light - nice to have on a grey, cloudy day, making the cabin seem less chill and claustrophobic.

Cons:

1. An insulated sliding sunshade is an absolute must. You can be broiled quite handily under that glass roof and put a heavy load on your AC with the shade open and the glass closed. The shade will block not only light, but practically all of the heat generated by the glass.
   
2. They can leak, but good ones, whether OEM or aftermarket, don't.
3. A canvas top of any kind is going to be noisy - it doesn't provide the acoustic insulation of a solid roof. Of course the degree this will probably have to be proven on the Elio, and will depend on how much noise we get from the engine and tires that may mask any exterior noise.
   
4. Any soft top, whether sunroof or full 'vert, has a built-in security problem. Any thief or vandal with a pocketknife can be in your car in seconds. Worse yet, you're going to have to replace the roof fabric after he's gone.

There have been long discussions over on one of the Lexus forums about the "drumming noise" produced by an open moonroof. After some research we found that a moonroof or sunroof can produce a "Helmholtz resonance" - the same thing that makes a flute produce sound - as air passes over a closed chamber (windows up, roof open). In most cars, it's a low-frequency thrumming that sounds around 40-50Hz - and loud enough to be maddening, if not painful at highway speed. It involves the natural resonance of the cavity (your cabin), and can be corrected by changing the embrochure (basically, lips, to us non-flautists). We can do that by closing the roof panel by about a half-inch to an inch and a half from its wide-open position, raising the natural frequency of the air passing over the opening out of the resonant range of the cavity.

It so happens that Lexus, at least - and probably other manufacturers have a solution for this in a "memory" that should be set by the dealer. I'm continually amazed at the number of dealers that don't take the time to adjust these presets for the new owner. There are at least a dozen, on the current Lexus, and I assume quite a few on other marques that maybe even the dealers aren't aware of . . . or haven't filtered down to the mechanics in the prep shop.

Like most electronic "owner preferences", it requires a sequence of ignition switches and button pushes to "memorize" this moonroof preset, but from that point onward, simply pressing the "open" button briefly should default the "open" position to that "not-quite-open" preset. If that's not enough opening for your tastes, a second press should open the moonroof to its mechanical stops. Using that "preset" will maintain blessed silence in the cabin, even at high speed.

Removable panels will always need a place to stow, and speaking from experience, erecting them in the rain normally involves finding a handy overpass or portico to leap out and dig your roof out of the trunk or back seat.

Avoid any multiple-pane roofs that retract one pane over another - OEMS found a lot of problems sealing the gaps between the glass panes to be a problem after a few months of use - and a constant drip down your neck in a rainstorm is a rather negative customer experience for a new owner.

Finally, if you should select an aftermarket moonroof - and that will more than likely be available . . . if not the identical product installed by your dealer. Don't shop price, but look for an experienced brand like American Sunroof (ASR) who has been furnishing both manufacturers and aftermarket shops an excellent product for 25 years. They've got it down pat.

 

[floydv]

Seth, how about larger versions of those flat metal springs with buttons that are used in umbrellas? You could get these to work with some tweaking of the "buttons" and they would give the compression and flex you're looking for. Just a thought.