Phaffing around in 3D

**Brian d marge** · 4th August 2009, 23:32

Well Ive started to build another bike, Engine, well there is only one ,,so it goes in a Plunger BSA frame
Now the object here is , No old bits can be harmed in the making of this bike ( including me )

2 , No Money can be spent where I can do it myself, that means if i need a mudguard , it is made, from scrounged steel or if the part is beyond me , ie tank making ... ( but I can take an existing tank and reshape it)

3, Arlen Ness and the swoopy brigade MUST hate it ( as must classic purists and engineers. and sport bike riders and people who call their kids Tristan )

4 The wife must not find out

and finally . Jockey shift ...thats a must have

Stephen

I attach a picture of whats happening, as i get a spare few moments I will add subtract and change bits ,,,so this is not some gleaming finished picture .....

**Brian d marge** · 12th August 2009, 17:46

Still phaffing

This ones an 'in' joke for work

Stephen

**Brian d marge** · 18th August 2009, 14:25

Hes another one , not drawn by me but I thought it was pretty cool

if it meshes ok and I dont have to spend much time fixing it... Ill try and put it through the CFD solver ,,,

Stephen

**Brian d marge** · 7th September 2009, 21:09

ok
I've finished the sketches happy with the way its going to look ,

finding a steel supplier and some gas and have figured out how I am going to make the front end

Just have to run the stresses to size the steel

and she's all go !

The battery box behing the engine is going top be a big ole antique wooden box with brass catches

of course this may change
Stephen

not sure on colour

**Fooman** · 8th September 2009, 09:56

Originally Posted by Brian d'marge

Just have to run the stresses to size the steel and she's all go !

Deflections may be more important than stresses. Check those too! Don't want to be ridding around on a nice looking blancmange!

Can you do a modal analysis for vibration as well?

Actually, having a quick think about it, what sort of BC's do you use - the fact that there is a load/deflection at both connection points (the headstock and rear suspension mounts) and only weight as a global load would mean some sort of global damping would be required to get sensible results (i.e. no pinned or fixed BC's, as they are unrealistic).

Cheers,
FM

**Brian d marge** · 8th September 2009, 13:36

Originally Posted by Fooman

Deflections may be more important than stresses. Check those too! Don't want to be ridding around on a nice looking blancmange!

Can you do a modal analysis for vibration as well?

Actually, having a quick think about it, what sort of BC's do you use - the fact that there is a load/deflection at both connection points (the headstock and rear suspension mounts) and only weight as a global load would mean some sort of global damping would be required to get sensible results (i.e. no pinned or fixed BC's, as they are unrealistic).

Cheers,
FM

Yes I am aware of the deflections
The frame has already been decided , BSA A7 but the front forks are mine , so load/deflections
I ll use Calculix FEA for a rough idea then go from there

I would like to get a better idea of deflections for a standard set of forks of about 35mm dia I know they walk in a figure of 8 but by how much I am not sure ( yet )

Stephen

Plunger isn't exactly the pinnacle of engineering finesse ,,,,

but it sure looks good !

**Brian d marge** · 8th September 2009, 20:50

and its looking like this will be an Art to part bike

as it looking increasingly like my workshop will be out of action for a while

The building of a new house

Stephen

**Brian d marge** · 17th September 2009, 17:45

just a quick update

Stephen

**Brian d marge** · 24th September 2009, 00:20

need a very short rear shock!

Carry on Nurse

Stephen

**Brian d marge** · 29th September 2009, 02:20

but im not so sure on an 140/70 18 rear

we will see what happens wen we add the rear mudguard

the COG is close to the wheel centre line so that's good ,

on track Huston !

Stephen

once the thing is drawn ,,,,then the hard bit of fleecing the wife of money begins

**Brian d marge** · 1st October 2009, 15:56

ok the layout is done I sort of know what is going where and the sizes ( will change as I look deper in depth )

the rear guard has to come up a bit depending on the deflection of the rear plunger ( dont know that yet !)

But basically this it what it is going to look like.

The round bit is a brass fire extinguisher for the air box and the box is the electrix and is beaten copper !

I will stick it on 3d to make it more life like !

Stephen

have informed the wife ........ I got

THE LOOK

**Brian d marge** · 11th October 2009, 22:11

I should put this post in a blog form ?

anyway dum dee dum

plunger unit next and rear hub

Stephen

**erik** · 12th October 2009, 08:57

It looks like its got negative trail (front tyre contact patch in front of where the steering head axis intersects the ground)?

**Brian d marge** · 13th October 2009, 02:23

Originally Posted by erik

It looks like its got negative trail (front tyre contact patch in front of where the steering head axis intersects the ground)?

about inch and a half of negative trail

should have about 4 inch of positive trail, but once its all drawn up and I start to check off each part that needs to be made

you can count your bottom dollar I will change it ( my gosh that would be interesting to ride) I will draw the rest of it up first then size and move things

I have drawn a skeleton and want to put him on it ! so will do that first ,,,,,

Stephen