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 Post subject: Re: sprite into locost
PostPosted: January 7, 2018, 1:03 pm 
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Joined: January 31, 2008, 5:34 pm
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Location: SW Wes Consin
I could do the double bearing rear hubs but I would like to get this thing built before I start down the improved performance rabbit hole.


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 Post subject: Re: sprite into locost
PostPosted: January 7, 2018, 4:15 pm 
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Location: Port Angeles. Wa
The Elan frame that you referenced is an aftermarket replacement frame by Spidercars in the UK. A stock Elan frame was mostly sheet metal.

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My build log viewtopic.php?f=36&t=10658&start=0 NOW NAMED =The Wycked 7


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 Post subject: Re: sprite into locost
PostPosted: January 7, 2018, 5:40 pm 
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vroom wrote:
I could do the double bearing rear hubs but I would like to get this thing built before I start down the improved performance rabbit hole.


Couldn't agree more with that sentiment - they are definitely an option when the time comes.

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 Post subject: Re: sprite into locost
PostPosted: January 7, 2018, 6:39 pm 
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Location: SW Wes Consin
Some thinking out loud:

I have found some Elan chassis drawings online. One is for an SE the other a +2. They look like they have pretty similar suspension mounting. The big difference, besides the extra 12" of wheel base, is that the SE has 7° of caster and the +2 has 3°. I'm not sure what effect caster has on handleing. I think this is something I should be learning soon as I plan to be welding the suspension cross member to the chassis. I could make it adjustable by bolting it on but this would take some really careful design and fabrication. And another potential failure point. So if I could come up with a good rule of thumb for caster I might try it.

Suggestions welcome.

PS On the plus side a bolt on cross member would be easier to repair/redesign etc.


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 Post subject: Re: sprite into locost
PostPosted: January 7, 2018, 10:05 pm 
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Joined: December 29, 2007, 10:41 pm
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Location: Vancouver, BC
Tim,
The chassis pic might have been from a Ginetta G4, I would repost it if it wasn't for photobuckets prices.

Rod


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 Post subject: Re: sprite into locost
PostPosted: January 13, 2018, 11:31 am 
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Location: SW Wes Consin
More caster thinking:
Ordered the front suspension out of a Spitfire and finished welding the top for my new welding / layout table during some reasonable weather (35°) this week. Today it is cold I am back to thinking about to about details of the Sprite to Spitfire swap. Both suspensions use trunnions which means their arms rotate in parallel. This is not good as it prevents having any caster adjustment except by rotating the front cross member. As this will be welded in place it is not much of an option. Caster angle is one of those swag numbers that are generally arrived at in testing after the build. The usual number varies from 1° to 9° so there is quite a range. The Elan used 7° and the Elan+2 3°. I am not sure why there is such a big difference. More caster causes the steering to self straighten more and causes more kick back. So I think I will error on the lessor side and go with 4°.
There is one other possibility that would give me some adjustment. That is to fab some new offset A arms and use Canley Classics suspension uprights which have a ball joint instead of a trunnion.


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 Post subject: Re: sprite into locost
PostPosted: February 13, 2018, 1:01 pm 
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Joined: January 31, 2008, 5:34 pm
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Location: SW Wes Consin
Warmer weather is back so I'm forming panels again. Any advice on how to form this anticlastic shape would be appreciated.


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 Post subject: Re: sprite into locost
PostPosted: February 14, 2018, 12:08 pm 
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Location: Carlsbad, California, USA
I can't tell you how to do it, but you might have some success finding help looking on YouTube. There are a good number of how-to videos now on making various complex shapes like saddle shapes. Try looking for videos by Peter Tommasini, Lazzie, Wray Schelin, Kent White (Tin Man), Ron Covell, etc.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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 Post subject: Re: sprite into locost
PostPosted: February 14, 2018, 6:23 pm 
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Location: BC, Canada. eh?
I think you're gonna need a sand-filled leather bag, a round faced plastic mallet, and access to an English wheel. If you can get all those things, you could make that shape in a couple of hours, and it would look...glorious. If you can't get access to an English wheel, it might be possible to do it with a (much cheaper) planishing hammer. I think I'd check out Harbor Freight for those items, if you don't know anyone who owns such tools...

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 Post subject: Re: sprite into locost
PostPosted: February 14, 2018, 6:41 pm 
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Location: Vancouver, BC
Tim,
Try something along the lines of this video:

https://www.youtube.com/watch?v=Et5WhaTyy4E

Form the curve you want in profile, then stretch the edges to get the reverse with a stretcher, then wheel with light pressure to smooth it.


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 Post subject: Re: sprite into locost
PostPosted: February 14, 2018, 7:08 pm 
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Location: BC, Canada. eh?
The shrinker-stretcher would work, for sure, although on a larger panel a deep-throat set might be needed to get a nice curve all the way through the piece. The shrinker-stretcher tools work incredibly well on long, narrow pieces - I use my set all the time, and I'm glad I purchased a set. Much of my build couldn't have been done (at least, not to my satisfaction) without them.

Still, I'd LOVE to have an English wheel!

Here's Lazze's second video, where he's doing a larger panel similar to the one that we're talking about here:

https://www.youtube.com/watch?v=jYzOwWNZIME

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 Post subject: Re: sprite into locost
PostPosted: February 15, 2018, 9:07 am 
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Saddles can be a real challenge. Check out the following video from Lazze. His rubber band on the English wheel makes a lot of stuff possible.

https://www.youtube.com/watch?v=eRvJHsNcnLA

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 Post subject: Re: sprite into locost
PostPosted: February 15, 2018, 10:23 am 
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@TooBusy

That video is really very instructive. Thanks for posting.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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 Post subject: Re: sprite into locost
PostPosted: February 18, 2018, 10:40 pm 
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Joined: January 31, 2008, 5:34 pm
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Location: SW Wes Consin
Thanks guys but Lazze's videos always make it look so easy but he never actually fits a part to a body, My anticlasic has different radii on all four edges. I think I'll go with Kerry Pinkerton's weenie die: https://www.youtube.com/watch?v=q3bom1USglo&t=221s Its never easy.


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 Post subject: Re: sprite into locost
PostPosted: February 19, 2018, 4:17 pm 
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Kerry's video should be https://www.youtube.com/watch?v=q3bom1USglo&t=8s I guess it was late.


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