Stopping the soft top ballooning at speed and liner

[chrisP]

Hi all, I am sure you have all experienced having the soft-top up and driving at speed - with the pressure differential the soft-top balloons away from the frame. Modern convertibles don't have this problem, as I guess there are extra connection points between the the fabric and the frame. My question has anyone looked into fixing this problem??

Secondly has anyone looked at or created an insulated liner

Cheers
Chris

[Rambo]

Easy solution. Open both windows a crack to equalise pressure. Result, no ballooning

[Bern]

Easily fixed, only drive with the roof down!

[simonbuk]

Does it matter though ?

And I guess any insulation added as an after thought might just attract/trap moisture ?

[chrisP]

Thanks for the help guys,

It does matter to an extent, once I get to a certain speed the soft top pulls the rear seal off the rear deck (yes the frame is tension-ed correctly).

With the liner I was wanting to make the car more live-able in inclement weather.

Chris

[Dave Eds]

I was wanting to make the car more live-able in inclement weather.

Chris

Beanie hat?

Bobble hat?

Ill get my coat..............

[Giniw]

once I get to a certain speed the soft top pulls the rear seal off the rear deck

That sounds strange to me, I never noticed that. It's ballooning a bit, but the rear seal doesn't move.
And my hood is not really well adjusted and the webbings are shot — it's another thing in my todo list.

[dapinky]

Chris,

There are a couple of vents between the boot and the interior to allow air pressure to equalise - they don't work if the boot is too full, and they are marginal at best.

Does it only happen with the dash vents open, or all the time?

[chrisP]

Hi Dave, yes the vents appear to be functional - well they are there and move, the boot is empty - but I have an idea that the vents actually suck exhaust gasses into the boot and passenger compartment (perhaps that is part of the issue perhaps not) But I have seen other Elan soft-tops ballooning. You just don't see it on modern convertibles

Chris

[Paul Alexander]

Thanks for the help guys,

It does matter to an extent, once I get to a certain speed the soft top pulls the rear seal off the rear deck (yes the frame is tension-ed correctly).

With the liner I was wanting to make the car more live-able in inclement weather.

Chris

Hi Chris, i used to get this problem. have you go the offset cams adjusted correctly on the sides of the hood frame, towards the rear? the cam should stop the hood lifting at speed (75 mph or above when it happened on mine).

[Rambo]

Hi Dave, yes the vents appear to be functional - well they are there and move, the boot is empty - but I have an idea that the vents actually suck exhaust gasses into the boot and passenger compartment (perhaps that is part of the issue perhaps not) But I have seen other Elan soft-tops ballooning. You just don't see it on modern convertibles

Chris

That's a problem you definitely dont want Sucking CO, CO2 and other exhaust gases into the inside cabin is a recipe for disaster.

[rip]

Easy solution. Open both windows a crack to equalise pressure. Result, no ballooning

Without going out specifically to test for this, it will have little effect.
It is because fast moving air creates a low pressure & was discovered by Daniel Bernoulli.
It is why aircraft can fly & why it is possible to sail partially into the wind.

[Rambo]

Easy solution. Open both windows a crack to equalise pressure. Result, no ballooning

Without going out specifically to test for this, it will have little effect.
It is because fast moving air creates a low pressure & was discovered by Daniel Bernoulli.
It is why aircraft can fly & why it is possible to sail partially into the wind.

It seems to work for me in the yellow one rip. Its probably down to Rambo's Theorem rather than Bernoulli's Principle

[Bern]

It is because fast moving air creates a low pressure & was discovered by Daniel Bernoulli.

I'm sure I'm totally wrong here, but isn't that sort of why opening a window works? You get lower pressure inside the car so the air inside is drawn out (and the ballooning stops)?

I did once drive at motorway speeds with the hood up (it was raining really heavily and I had a passenger who wasn't a fresh air enthusiast, tsk), I don't remember there being any ballooning of the hood.

[Simon_P]

The tension sets the frame go over-centre on the pivot, which locks the panel in place on the rear deck.

You can only unlock it by folding the hood, so if it is lifting something is wrong with the hood frame adjustment.