by "BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
Published 05/28/2017 at 18:43
by "BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
Published 05/28/2017 at 18:43
Tags: Spit6
STARS: 17
Promise the welds look better in real life ;) went for the ‘make sure it’s stuck’ school of welding rather than ‘make it pretty’.
Started with the little jig i made earlier:
Cut some tubes :)
Should rephrase that. Spent half a day cutting tubes because cutting tubes is hard.
Made some little jig pieces to copy the cuts i need so i can make more of them of i need to :)
First two tacked in place:
And the rest welded together :)
I found that the heat put into it from welding warped the inboard end enough to pull it out of alignment, so for the second wishbone i used a clamp which has worked much better :)
All-in they weigh 2.1kg per side which is really not bad :) for reference, the stock rotoflex wishbone and radius arm weigh 3.4kg. Although my earlier design with basically two radius arms was a little lighter at 1.3kg, the new setup will provide much better location and a better camber curve.
Another difference is the adjustability for camber on these isn’t quite as fine. Because the threads are fixed, the adjustment is done in half-turns of the rose joints. For 1/2" UNF thread it’s 0.39mm per half-rotation, which equates to 0.13 degrees of camber change per half-turn which is plenty fine enough :) still have to work out toe change per rotation as that involves trig and i’ve forgotten all that by now...
Now i just need to work out something to get the brackets on the car in the right place...
"ptak appreciates old racecars" (racecarptak)
05/28/2017 at 23:17, STARS: 1
This is excellent oppo, 10/10
"Jobjoris" (Jobjoris)
05/29/2017 at 04:29, STARS: 1
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
05/29/2017 at 04:54, STARS: 0
Thanks dude! :)
"Cé hé sin" (michael-m-mouse)
05/29/2017 at 06:16, STARS: 1
Not, if we can just know why the balance says “weight, milk, water”....
"BvdV - The Dutch Engineer" (dutchengineer)
05/29/2017 at 07:06, STARS: 1
Awesome job! I can’t wait to see how the full suspension setup turns out, and to see if your handling calculations were indeed right.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
05/29/2017 at 09:39, STARS: 1
Thanks man :) it’s getting to the point where i get to do a dry fit of all the components which will be a huge step forwards :)
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
05/29/2017 at 09:40, STARS: 0
Maybe i should start reporting weights in ml of milk...
"BvdV - The Dutch Engineer" (dutchengineer)
05/29/2017 at 10:23, STARS: 0
That will indeed really be a huge step, you’ll probably go from a shell to a roller in a relatively short time if everything works out.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
05/29/2017 at 17:09, STARS: 1
I bloody well hope so! It’s been long enough ;)
"davedave1111" (davedave1111)
05/29/2017 at 18:58, STARS: 0
Loving the progress. If you could speed things up just a little, I might give up all thoughts of my own car projects and just live vicariously off yours while making things I can actually achieve.
I note that my comment about how I was thinking about selling the F was just about the only one I’ve made where you haven’t either starred it or replied - did I finally shock you? ;)
To be clear on that, if you have any suggestions of convertibles that are much looser at the back end, I’m all ears.
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
05/29/2017 at 19:43, STARS: 0
Haha, perhaps it was unconscious bias ;) I thought I’d forgotten to reply to something!
I can sort of see what you mean with the F being a bit too sticky for a lot of the roads here, although I’ve always found mine to be fun even at lower speeds.
If you want something that’s a little easier to kick the rear end out then my mate’s NA MX-5 has always been a little tail-happier than my F, especially with an LSD. You can get LSDs for Fs, but they’re Quaife ones which cost an arm and a leg :S
You can get them sliding out of junctions without one though :) it does involve being a fair amount heavier on the clutch-drops than feels right for anyone with mechanical sympathy, but rainy days help with that ;)
Sitting in his MX-5 it does feel a little more ‘old school’ though which is really nice. I can definitely see why all the older blokes who drove Triumphs and MGs in the 60s felt at home in the NA MX-5.
"davedave1111" (davedave1111)
05/30/2017 at 07:28, STARS: 0
“I’ve always found mine to be fun even at lower speeds.”
It’s still fun, but is it more fun than e.g. a Panda at those speeds? Hell, even the Camry likes <30mph esses and so-on.
Maybe I should just have had the thing on ditchfinders instead of the Contis!
I meant to ask, re your project and welding. Could you get a cosmetic improvement by grinding back the welds with a small Dremel head or similar, or would that risk the integrity?
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
05/30/2017 at 08:13, STARS: 0
I’d say so ;) you have to be a bit more of a hooligan though. Less slidey, more testing just how far the grip will go.
Yeah you can grind welds back to get them looking much better. I’ve found the sanding disks you can get for angle grinders to be really effective, but also not eat away at the surrounding metal if you slip or brush over an unwelded area.
It’s something I do on cosmetic stuff, but for wishbones I wouldn’t want to risk thinning the welded section too much and introducing weakness.
"davedave1111" (davedave1111)
06/02/2017 at 10:30, STARS: 0
The problem with testing how far the grip will go is that the answer is way, waaay beyond legal or sane speeds.
Re the welding, have I misunderstood something? I thought the weld is as strong as the metal, so as long as it’s not porous, shouldn’t you be able to grind it back roughly level without any issues?
Have you tried a powerfile?
"BiTurbo228 - Dr Frankenstein of Spitfires" (biturbo228)
06/02/2017 at 19:45, STARS: 0
Hmmm, perhaps tyre choice might be driving that. I’ve been very pleased with my Toyo Proxes T1Rs on mine. They’re grippy in the dry, but in the wet they’re...marginal. Driving cautiously in the wet they’re absolutely fine, but it’s very easy to get sideways out of junctions and through corners. Seems like a reasonable balance for me :)
You’re pretty much right. Weld is slightly harder than regular carbon steel, so more likely to crack if it flexes, but that’s marginal. The main issue with grinding back welds is that it’s quite easy to end up with really quite a thin joining section and not know it. Not something you want on a wishbone. I’m sure it’d be fine, I jsut don’ twant to risk it.
There might be something else about the scoring from a grinding disc being stress risers, but pass on how much that affects it.