sgraber
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| posted on 11/9/06 at 05:18 PM |
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Bonnet hinging :: ideas please?
Can people post up images of hinges for clamshell front ends?
I need ideas. 
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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John Bonnett
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| posted on 11/9/06 at 05:35 PM |
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Bonnet Hinge
Hi Steve
I was wondering whether the set up I have on the Phoenix might work for your car. There is a tubular cross piece onto which are fitted two sleeves
each having a braket welded on. These brackets are made of 2mm thick x 30mm wide strip. the brackets bolt up to the radiator ducting on the bonnet as
shown in the picture. I'm sorry that I do not have a picture of the hinge assembly before the bonnet was fitted but I hope you get the idea.
alb
John
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John Bonnett
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| posted on 11/9/06 at 05:42 PM |
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Sorry Steve the picture did not come over. Will try again
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John Bonnett
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| posted on 11/9/06 at 05:51 PM |
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Don't you just hate it when things fight back!
Here are the pics, I hope!!
John
http://i93.photobucket.com/albums/l57/bonnett_2006/phoenix38001Small.jpg
http://i93.photobucket.com/albums/l57/bonnett_2006/phoenix39003MediumSmall-1.jpg
John
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sgraber
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| posted on 11/9/06 at 05:59 PM |
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ahh, I see. So it hinges from the very bottom-front most part of the bonnet?
That was where I had though was the best place for mine. But I am concerned that the slightest impact to the bottom lip of the car would make it
impossible to open the bonnet if the hinge were to get mis-aligned. Am I overthinking this?
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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StevieB
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| posted on 11/9/06 at 06:06 PM |
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If it hinges at the very bottom edge, it'll need to be very far forward, or there's a chance of scraping the nose on the ground when it
opens
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sgraber
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| posted on 11/9/06 at 06:15 PM |
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quote:
Originally posted by StevieB
If it hinges at the very bottom edge, it'll need to be very far forward, or there's a chance of scraping the nose on the ground when it
opens
Understood. Are there any issues with placing the hinge so low and forward on the car? I am guessing that frontal impacts of any magnitude, no matter
how small, will transmit forces into the frame directly rather than allowing the fiberglass to crush and crack and buffer?
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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StevieB
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| posted on 11/9/06 at 06:19 PM |
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How about having the front edge being fixed and hinging from a foot or so back, that way you get around the impact potential to knacker the chassis,
you have a scarificial zone for any crash damage and maybe better aerodynamics as well.
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JonBowden
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| posted on 11/9/06 at 06:59 PM |
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quote:
I am guessing that frontal impacts of any magnitude, no matter how small, will transmit forces into the frame directly rather than allowing the
fiberglass to crush and crack and buffer?
My worry about such designs of bonnet where there is no windscreen is that in the event of a bad crash, the whole thing might come off and chop the
driver's head off
Jon
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Mark Allanson
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| posted on 11/9/06 at 07:34 PM |
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Just about to post the very same thing!
I was going to recommend glassing in hooks that would engage onto the chassis in the event of an accident and restrain the rear of the bonnet, another
upside of this is that the bonnet then absorbes masses of kinetic before the chassis takes over the decelleration. Tahe a look at any volvo front
opening bonnet for parts/ideas.
Pantograph hinges are also a good idea because they will lift the front of the bonnet as it is opened (ideal for a low chinned sportscar).
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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sgraber
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| posted on 11/9/06 at 11:23 PM |
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I'm considering pantographic hinges as they are not that difficult to fabricate. However. straight up hinges at the bottom/front are really so
much simpler ...
I've been looking at a lot of tilt-clamshell 'kits' (google) and none that I have seen use anything but straight hinges...
My car has a windshield, so I feel that the decapitation issue is moot in my case.
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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John Bonnett
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| posted on 12/9/06 at 07:11 AM |
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Hi Steve
I should have pointed out that the hinge assembly on the Phoenix is like a small subframe that is designed to be crushable. If you are really
interested in the design, I can take the bonnet off and take some detailed photos.
Please let me know.
alb
John
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chriscook
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| posted on 12/9/06 at 09:31 AM |
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The same idea is used on the Fisher Fury - there are probably more photos of Furys around than Phoeni(?)
In fact after a quick look on the Sylva sportscar register I found this picture and you
can see the frame at the front of the car with the hinges hanging down.
Chris
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sgraber
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| posted on 12/9/06 at 03:11 PM |
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Thanks Jon and Chris,
I now have a pretty good idea of how to attach a lightweight, sturdy and deformable hinge structure after looking at the Sylva.
Appreciated!
Graber
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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RazMan
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| posted on 13/9/06 at 10:42 PM |
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Steve - This might give you an idea of how my Aeon's front end is hinged - basic but effective. I would consider a couple of largish rod ends to
give adjustability though.
 
Rescued attachment Front mounting frame.jpg
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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