Help - Flapping Bonnet!!?

[Bayside]

Cryptic title - genuine problem!

At motorway speed around the 70mph mark the bonnet on my Gen2 wobbles about - its well and truly shut and on the catch but looking along the bonnet the front corners wobble like they are trying to lift.This wobble and shake can be seen all along the edges and right upto the corners and panel gap nearest the windscreen?

Its as if something is trying to fight its way out!!

The only thing I can think is that air is being forced in the engine bay possibly worsened by the body lift and trying to get out through the bonnet. Its got a bonnet lip / spoiler fitted which in theory should help?

Over distance my concern is that it may work loose and open - which could get messy

[BUSHWHACKER]

It's the bug deflector causing disturbence in the airflow. As the air flows over it, it creates a low pressure area behind it.
Basically the bonnet is being sucked upwards.

[puddlesurfer]

It's the bug deflector causing disturbence in the airflow. As the air flows over it, it creates a low pressure area behind it.
Basically the bonnet is being sucked upwards.

I know this one! It's bernoulli's principle! I did it in science about 20 years ago I knew education would pay off one day!

Bernoulli's Principle states that an increase in the speed of moving air is accompanied by a decrease in the air pressure.

[Albannach]

Pah! Bernouli is a pain in the arse some times...

[TonyN]

Vince is right, if anything it'll make it worse not better, but dosn't usually affect it though, I've had them on trucks and it's been ok.

Make sure the two rubber supports at the front corners are touching the bonnet, they help brace it against the latch and keep it tight.

[Bayside]

So not much can be done about it then..... I like how it looks!

Other than taking it off anything that might help?

What about some small slit vents in the deflector to decrease the air pressure as on some motorcycle screens?

[puddlesurfer]

Pah! Bernouli is a pain in the arse some times...

I think that's probably just wind - are you experiencing a pressure drop due to fast moving air?

[gwh200]

I know this one! It's bernoulli's principle! I did it in science about 20 years ago I knew education would pay off one day!

Bernoulli's Principle states that an increase in the speed of moving air is accompanied by a decrease in the air pressure.

Err.no


I think you will find bernouillis eqn is p1,v1,t1=p2,v2,t2.
It relates to two moles of different gas,both containing Avogadros number** of molecules, when p1,v1,t1=p2,v2,t2.

Just saying like. Oh it also quantifys Boyles gas law.

** 6.23x10^23.

I fang you and goot eefenink.

[Predictable Bob]

You could try reading this ...

[Bayside]

Ah - my reply landed after Tony's

Was thinking about the rubbers at the front - Ill take a look tommorrow.

The truck is in a state of minimalist bodywork at the moment anyways as trying to sort the underside and given up on the rear bumper - going to fabricate a steel one. Incorporate the side steps into some rock sliders as the old tubework supporting the steps is knackered, Possibly make a new bumper and address the poorly constructed bull bar........ Ill add it to the seemingly NEVER ENDING list of things to do before the truck is the condition I'd like it to be!

[puddlesurfer]

Err.no


I think you will find bernouillis eqn is p1,v1,t1=p2,v2,t2.
It relates to two moles of different gas,both containing Avogadros number** of molecules, when p1,v1,t1=p2,v2,t2.

Just saying like. Oh it also quantifys Boyles gas law.

** 6.23x10^23.

I fang you and goot eefenink.

Is that Susan Boyles law or Frankie Boyles law?

[puddlesurfer]

Ah - my reply landed after Tony's

Was thinking about the rubbers at the front - Ill take a look tommorrow.

The truck is in a state of minimalist bodywork at the moment anyways as trying to sort the underside and given up on the rear bumper - going to fabricate a steel one. Incorporate the side steps into some rock sliders as the old tubework supporting the steps is knackered, Possibly make a new bumper and address the poorly constructed bull bar........ Ill add it to the seemingly NEVER ENDING list of things to do before the truck is the condition I'd like it to be!

Good luck with the truck! I hope you get it the way you want it, I keep coming up with more and more jobs I want to do to mine too!

We will need pics of all the stuff you make please!

[Albannach]

As for bonnets, mine wibbles a wee bit too.

[BUSHWHACKER]

As for bonnets, mine wibbles a wee bit too.

Try tying the ribbon a little tighter under your chin.

[Albannach]

Try tying the ribbon a little tighter under your chin.

That only helps with flapping, wibbling is a whole new kettle of sardines.