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#Post#: 9181--------------------------------------------------
Auto Union type C The difficult second CycleKart
By: Jimr1999 Date: July 30, 2023, 2:31 am
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Ever since I got half way through the build of the BSA, I knew I
would build another - I was having too much fun with the first
one. Looking at past build journals and the American sites, I
knew it was not going to be easy. I would want to build upon my
mistakes and attempt something very different at the same time.
I have been collecting bits and messing around with ideas for
about ten months now but it was not until an idea for front
suspension based upon a 1930's Porsche design was mooted (Hat
tip to Giant Tribble) that I got my dander up as to what to
build. The build will employ little of my traditional wood based
skill set (big challenge and lots to learn). I set about trying
to replicate the suspension design and I now have 80% faith that
I can do it. Good enough to make a start.
A couple of rough sketches and a video to show how I intend to
tackle the problem. Not a definitive design yet and very much
work in progress.
If you are reading Stefan, please reserve me race number 6.
HTML https://youtu.be/pQ9Li73aV60
JimR
#Post#: 9182--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: Ian F Date: July 30, 2023, 3:14 am
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Good luck with the build Jim. You learn so much from your first
build which is a great help when doing another.
#Post#: 9184--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: NewbieNick Date: July 30, 2023, 3:25 am
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Good luck very interesting build. Does the type A have 4 back
wheels?
Cheers Nick
#Post#: 9185--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: Jimr1999 Date: July 30, 2023, 3:29 am
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Not this one Nick, it was run with four total. It is the first
iteration of A,B,C and D and had scoops rather than louvres...
HTML https://www.flickr.com/photos/93207294@N04/22136455022/in/photostream/
#Post#: 9186--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: Jimr1999 Date: July 30, 2023, 3:35 am
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General layout...
#Post#: 9232--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: IanA Date: August 7, 2023, 2:28 pm
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Good to meet you at Newark, Jim.
You have just solved the front suspension quandary I had about
my inspiration car.
The twin trailing arms are reminiscent of my TVR Grantura which
used early VW Beetle suspensin with a sheaf of torsion bars
anchored in the centre of a tube. The arms themselves were
supported in fibre bushes.
The MX-5 ARBs with bump stops look like a goer to me.
#Post#: 9234--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: Jimr1999 Date: August 8, 2023, 1:44 am
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[quote author=IanA link=topic=1159.msg9232#msg9232
date=1691436504]
Good to meet you at Newark, Jim.
You have just solved the front suspension quandary I had about
my inspiration car.
The twin trailing arms are reminiscent of my TVR Grantura which
used early VW Beetle suspensin with a sheaf of torsion bars
anchored in the centre of a tube. The arms themselves were
supported in fibre bushes.
The MX-5 ARBs with bump stops look like a goer to me.
[/quote]
Thanks Ian, good to meet you too. As far as I am aware, it was a
Porsche design and probably started life on the Auto Union type
A. Here is a reasonable image of the type D suspension, I think
little changed from the type A, it had friction dampers on the
top arms...
HTML https://upload.wikimedia.org/wikipedia/commons/7/7b/Auto_Union_Typ_D_Detail_Radaufh%C3%A4ngung_EMS.jpg
JimR
#Post#: 9241--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: RhysN Date: August 10, 2023, 1:56 am
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As an option for the trailing arms have you had a look at
bicycle pedal cranks, and using the long socket extension bars
for the torsion bars?
In regard design, the Auto Union was a Porsche design as above.
#Post#: 9242--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: Jimr1999 Date: August 10, 2023, 2:14 am
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[quote author=RhysN link=topic=1159.msg9241#msg9241
date=1691650566]
As an option for the trailing arms have you had a look at
bicycle pedal cranks, and using the long socket extension bars
for the torsion bars?
In regard design, the Auto Union was a Porsche design as above.
[/quote]
I have yet to see it done that way Rhys, my issue with that
idea, which was first mooted by the Giant Tribble in a design he
produced as a concept, was the clearance for the turn of the
wheels - bicycle cranks would not have given me much lock to
interference without a lot of projection on the ball joints,
which are probably the weak point of the design. I looked at
torsion bar inclusion first, As that would have been authentic -
I talked to Rick Eggers in the states as he has a great design
but not transverse, in line, and he had to machine his socket
extensions down to get the spring rate correct. - the MX5 bars
are too stiff in their own right at 18mm (Although 5### series
spring steel) - As the width of the CK limits the effective
length of the torsion bar, including a link to another torsion
bar seemed unnecessarily complicated/heavy/space
consuming/inauthentic when rubber would do the trick (think Mini
mk1?).
All very experimental Rhys at the moment and without trying I
will never know if it will work. The plan is to get the front
end welded up and braced first to test the deflection, bounce,
rebound and the necessity for dampers before going ahead with
the rest of the work. Things are busy here at the hacienda so it
will probably be September before I know how well it performs.
JimR
#Post#: 9243--------------------------------------------------
Re: Auto Union type A - The difficult second CycleKart
By: synthpunk Date: August 10, 2023, 6:31 am
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Yay, rubber cones! My Riley has a rear suspension system based
on them, too. Works a treat.
The rear end is balanced between two sets of cones pressing up
on the bottom, with slightly different hardness on each pair to
provide rebound control and damping, and lots of rubber bands
pulling down from the top doing the actual suspension part of
the job.
Ive had it off-road a couple times, works surprisingly well over
a rough field.
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