Are you madabout kit cars      
 "We've Got Kit Cars Covered" Information about Madabout-Kitcars.com Contact Madabout-Kitcars.com         Home of UK kit cars - madabout-kitcars.com Various kit car write ups All the latest kit car news Kit car related and general discussion

Search
Manufacturers
Kit Cars
Kit Car Data sheets
Picture Gallery
SVA Knowledgebase
Clubs & Communities
Build cost estimator
Kit cars for sale
Knowledge Base 
KitcarUSA.com
Classic-Kitcars.com
 

Go Back   Madabout Kitcars Forum > Mad Build Area > Vintage and Classic Roadster Kit Car Builds

Vintage and Classic Roadster Kit Car Builds For Vintage and Classic era kit cars. Post your build reports, problems and progress here

Reply
 
Thread Tools Display Modes
  #1  
Old 25th October 2016, 10:38
Car photographer Car photographer is offline
Senior Member
 
Join Date: Apr 2014
Location: Birmingham, UK
Posts: 545
Car photographer is on a distinguished road
Default Cycle wings - best way to mount them?

Hi everyone, so ever since I finished my Fiorano kit I've been constantly having problems with my wheel arch supports.
They are currently made from steel tube that's welded together, and they seemed pretty strong, but it seems that almost every time I drive the car one of the welds snaps off and the other day the tubeitself actually sheared off.

Does anyone have any ideas of what the best method of attaching the wings could be?
Reply With Quote
Available from eBay
  #2  
Old 26th October 2016, 06:18
redratbike's Avatar
redratbike redratbike is offline
Senior Member
 
Join Date: Sep 2011
Posts: 1,446
redratbike is on a distinguished road
Default

Pics would help so we could see the current set up and make suggestions

Last edited by redratbike; 26th October 2016 at 06:21..
Reply With Quote
  #3  
Old 26th October 2016, 22:07
Car photographer Car photographer is offline
Senior Member
 
Join Date: Apr 2014
Location: Birmingham, UK
Posts: 545
Car photographer is on a distinguished road
Default

Ok I'll try and sort some out
Reply With Quote
  #4  
Old 27th October 2016, 00:19
molleur molleur is offline
Senior Member
 
Join Date: Jun 2015
Posts: 1,401
molleur is on a distinguished road
Default

Quote:
Originally Posted by Car photographer View Post
Hi everyone, so ever since I finished my Fiorano kit I've been constantly having problems with my wheel arch supports.
They are currently made from steel tube that's welded together, and they seemed pretty strong, but it seems that almost every time I drive the car one of the welds snaps off and the other day the tubeitself actually sheared off.

Does anyone have any ideas of what the best method of attaching the wings could be?
Should you have a good library around, you may try this reference:
Sports Car Bodywork: Construction in Timber, Metal and Plastics
B.W. Locke, 1960 or 1961.
Great old reference, with fold out blueprints. Dreadfully expensive even used.
He shows a foolproof method for exactly what you are looking for.
I (insanely) gave away my copy to a kit manufacturer in Michigan.
Reply With Quote
  #5  
Old 27th October 2016, 20:06
MartinClan's Avatar
MartinClan MartinClan is offline
Senior Member
Enthusiast
 
Join Date: Sep 2004
Posts: 1,890
MartinClan is on a distinguished road
Default

It's unlikely that tube will be strong enough. It may appear to be stiff, but will inevitably tear at the welds. My Marlin uses solid round bar about 10mm as I remember. Done about 6000 miles with no problem. My Pembleton has 8mm round bar. Too soon to tell if its ok though. But mudgaurds much lighter than Marlin so I am hopefull...

Mudguards that move with the wheels get a lot of pounding. Its a common problem area.

Cheers, Robin
Reply With Quote
  #6  
Old 27th October 2016, 20:43
Car photographer Car photographer is offline
Senior Member
 
Join Date: Apr 2014
Location: Birmingham, UK
Posts: 545
Car photographer is on a distinguished road
Default

Thanks guys, yeah someone said solid bar might work better, also do you think it might help to have a layer of rubber sheet between the brackets where they bolt onto the hubs?
Would this help dampen the vibration?
Reply With Quote
  #7  
Old 27th October 2016, 22:11
molleur molleur is offline
Senior Member
 
Join Date: Jun 2015
Posts: 1,401
molleur is on a distinguished road
Default

Quote:
Originally Posted by Car photographer View Post
Thanks guys, yeah someone said solid bar might work better, also do you think it might help to have a layer of rubber sheet between the brackets where they bolt onto the hubs?
Would this help dampen the vibration?
Perhaps, but I see it as adding a lot of additional bouncing on the wings.
Reply With Quote
  #8  
Old 28th October 2016, 22:21
paul_n paul_n is offline
Member
 
Join Date: Oct 2015
Posts: 83
paul_n is on a distinguished road
Default

Seen this ?

http://www.hotrodders.com/scratch-bu...Running_Boards

of course no one has asked who did the welding ? and with what ?

regards Paul
Reply With Quote
  #9  
Old 29th October 2016, 12:46
Mitchelkitman Mitchelkitman is offline
Senior Member
 
Join Date: Oct 2013
Location: norfolk
Posts: 691
Mitchelkitman is on a distinguished road
Default

It can depend on how you are attaching them as to how the design pans out. My experience with stays that clamped on the hub (mgb based kit) was similar (ie welds failed.) To cure it I made some solid round 'plugs' about 4" long which I heated up red and flattened the end and drilled for mounting. The other end of the plug had the last 1.5" turned down so it was tight fit in the steel tube (seamless gas tube) and the parts were brazed together. The logic being that cycle frames (very thin and light) take enormous stresses (think bike forks) and have been traditionally made this way. At the top end I also used a tube bender to bend to 90 degrees so no 'corners' as stress raisers. It worked.
Reply With Quote
  #10  
Old 30th October 2016, 10:17
Car photographer Car photographer is offline
Senior Member
 
Join Date: Apr 2014
Location: Birmingham, UK
Posts: 545
Car photographer is on a distinguished road
Default

Ok, here's some pics.
first one is the hub where the tab that supports the arch bracket is welded. (there's one on the other side of the hub too that's hidden in this shot)
1DSC_0505 by paul ward, on Flickr

and this is the arch support itself - the 'nodular lump at the bottom is the latest temporary repair where the tube sheared off.
DSC_0026 by paul ward, on Flickr

DSC_0025 by paul ward, on Flickr

Last edited by Car photographer; 30th October 2016 at 10:21..
Reply With Quote
  #11  
Old 30th October 2016, 16:45
slickshod slickshod is offline
Junior Member
 
Join Date: Jan 2014
Posts: 17
slickshod is on a distinguished road
Default

Hi Paul are they braking at the weld or across it ? and what method of welding are you using ? could you mount them on rubber bushes to absorb any vibrations ,I had to use this method on a Westfield.
Reply With Quote
  #12  
Old 30th October 2016, 17:51
Car photographer Car photographer is offline
Senior Member
 
Join Date: Apr 2014
Location: Birmingham, UK
Posts: 545
Car photographer is on a distinguished road
Default

Quote:
Originally Posted by slickshod View Post
Hi Paul are they braking at the weld or across it ? and what method of welding are you using ? could you mount them on rubber bushes to absorb any vibrations ,I had to use this method on a Westfield.
Both, they have broke several times, sometimes the welds snapped off and also the tube sheared off
Reply With Quote
  #13  
Old 30th October 2016, 18:36
Mitchelkitman Mitchelkitman is offline
Senior Member
 
Join Date: Oct 2013
Location: norfolk
Posts: 691
Mitchelkitman is on a distinguished road
Default

Are they tube or solid? I think the welding is causing embrittlement of the steel, leading to the tube breaking in the heat affected zone (ie close to weld). If solid (or tube) you could slot them to take a 6mm plate (nice tight fit in slot) and braze them - look at chainstays or seatstays where they meet the rear dropout on a quality brazed cycle frame. Brazing acts at a lower temperature so doesn't cause the embrittlement problems that welding does - that's why it's been used in bike frames for over a century! Good old-fashioned simple engineering is sometimes the best You may have to replace some of your metal that is already heat affected?
Reply With Quote
  #14  
Old 31st October 2016, 10:06
slickshod slickshod is offline
Junior Member
 
Join Date: Jan 2014
Posts: 17
slickshod is on a distinguished road
Default Welds Fracturing

Totally agree with the above ,stress due to heat is likely causing the brake especially in thin wall tube ,brazing or solid inserts at the weld will solve the issue ,good luck keep at it !
Reply With Quote
  #15  
Old 31st October 2016, 15:22
paul_n paul_n is offline
Member
 
Join Date: Oct 2015
Posts: 83
paul_n is on a distinguished road
Default

You don't say what welding method is being used also what is the thickness of the tube compared with the bracket thickness ?

It is possible you are getting undercuts which reduce the wall thickness at the point of maximum stress i.e the tube/bracket interface ?

If you put a internal sleeve into the tube and tapered the inside end to spread the stress you would double it's thickness at the point of the weld ?

Don't forget if you make one part stronger and unable flex you just move the forces somewhere less strong , sometimes flex is best
Reply With Quote
  #16  
Old 31st October 2016, 17:17
Car photographer Car photographer is offline
Senior Member
 
Join Date: Apr 2014
Location: Birmingham, UK
Posts: 545
Car photographer is on a distinguished road
Default

Thanks for the input everyone
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +0. The time now is 18:37.

copyright © madabout-kitcars.com 2000-2024
terms and conditions | privacy policy