Recumbent trike drawing

Wally said:

I mentioned in another thread that I have an eye on making a recumbent trike
at some point. The idea is still developing in my CAD software, and is
starting to look like a trike. The following link takes you to a page with a
rotatable 3D model (I suspect the viewer plug-in may be Windows-only).

http://www.melodolic.com/3D/ChassisAssy-02/ChassisAssy-02.htm

There is a Mac viewer but it is a standalone application. Do you have a
direct link to the file?

...d

Quoted message said:

So far, I've set out the main geometry - positioning the axles, setting the
kingpin angles, and experimenting with steering geometry. It's an Ackerman
set up - the crossover point is about 70mm behind the rear axle. In my CAD
model, I have a pair of concentric circles drawn to show the track each
front wheel should follow, and it all seems to line up okay. The main
geometry is lifted straight from...

http://www.ihpva.org/com/PracticalInnovations/index.html

In the online model, there are remnants of a universal joint and steering
column bracket (I was originally looking at an OSS set up, but have just
been convinced that USS is the way to go - gotta pick one, that's what I've
chosen. Have just added a handlebar, which is stuck for now on the aft end
of the arm that comes back from the pivot. I also had a go at a seat frame
to check clearance, and it isn't too bad now that I've made curvy corners.
Unfortunately, the crossmember tubes get in the way of the forward bar end
and stop the other one getting near the seat!

There's lots still to do, It's certainly nowhere near a set of fabrication
drawings, but it'll have to get pretty close before some key bits can be
made. For example, still need to design a makable shape for the uprights
(the wiggly things with the kingpin and the steering arm).

Comments invited, particularly regarding geometry and steering.

--
Wally
www.artbywally.com
www.wally.myby.co.uk

David Martin said:

There is a Mac viewer but it is a standalone application. Do you have
a direct link to the file?

Try...

http://www.melodolic.com/3D/ChassisAssy-02/1850668_1.easm

--
Wally
www.artbywally.com
www.wally.myby.co.uk

Wally said:

David Martin said:

There is a Mac viewer but it is a standalone application. Do you have
a direct link to the file?

Try...

http://www.melodolic.com/3D/ChassisAssy-02/1850668_1.easm

Thanks.

The handlebars look a long way forward. Much closer to the hips (just
about on the front edge of the seat) would be my preference.

...d

Wally said:

I mentioned in another thread that I have an eye on making a recumbent trike
at some point. The idea is still developing in my CAD software, and is
starting to look like a trike. The following link takes you to a page with a
rotatable 3D model (I suspect the viewer plug-in may be Windows-only).

http://www.melodolic.com/3D/ChassisAssy-02/ChassisAssy-02.htm

Not only that, but according to itself, specifically Internet
Explorer-only.

Quoted message said:

Comments invited, particularly regarding geometry and steering.

.... but only from internet-explorer users.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Wally said:

In the online model, there are remnants of a universal joint and steering
column bracket (I was originally looking at an OSS set up, but have just
been convinced that USS is the way to go - gotta pick one, that's what I've
chosen. Have just added a handlebar, which is stuck for now on the aft end
of the arm that comes back from the pivot. I also had a go at a seat frame
to check clearance, and it isn't too bad now that I've made curvy corners.
Unfortunately, the crossmember tubes get in the way of the forward bar end
and stop the other one getting near the seat!

Haven't taken a look at the model yet but if you need it, another
justification for USS (on a trike) is that it provides more lateral
support when cornering. OSS makes leaning into corners difficult and
half (or more!) of the fun of trikes is hairing round bends!

The other possibility to consider (which makes the design a little
easier in many ways) is to use Catrike style direct steering. Link the
kingpins but attach your steering handles directly to the kingpins.

Good luck.

Jon

David Martin said:

The handlebars look a long way forward. Much closer to the hips (just
about on the front edge of the seat) would be my preference.

I'll have a go at moving them back, and maybe try the third linkage idea to
stop the handlebar centre point swinging about too much.

--
Wally
www.artbywally.com
www.wally.myby.co.uk

Jon is Away! said:

Haven't taken a look at the model yet but if you need it, another
justification for USS (on a trike) is that it provides more lateral
support when cornering. OSS makes leaning into corners difficult and
half (or more!) of the fun of trikes is hairing round bends!

Yes, I'm into the idea of being able to brace myself against something
solid. (That was why I had the steering column bracket in the OSS version
with the UJ.)

Quoted message said:

The other possibility to consider (which makes the design a little
easier in many ways) is to use Catrike style direct steering. Link the
kingpins but attach your steering handles directly to the kingpins.

That sounds a bit weird, A possible issue with that is the way the steering
handles rotate, since the kingpins aren't vertical. They'd move in weird
planes. Using a normal bar and rose joint style linkages means that you can
control the plane the bar moves in independently of what the kingpins do.

--
Wally
www.artbywally.com
www.wally.myby.co.uk

Ian Smith said:

Quoted message said:

... (I suspect the viewer plug-in may be Windows-only).

Quoted message said:

Not only that, but according to itself, specifically Internet
Explorer-only.

So?

Quoted message said:

Quoted message said:

Comments invited, particularly regarding geometry and steering.

Quoted message said:

... but only from internet-explorer users.

-----------------------
If you are having difficulty viewing the 3D model, visit the SolidWorks web
site and download the eDrawings viewer... Go to SolidWorks web site
-----------------------

--
Wally
www.artbywally.com
www.wally.myby.co.uk

Wally said:

Ian Smith said:

Quoted message said:

... (I suspect the viewer plug-in may be Windows-only).

Quoted message said:

Not only that, but according to itself, specifically Internet
Explorer-only.

So?

You suggested that you weren't certain whether it limited people or
not, so I confirmed at least one part of the apparent limitation. My
apologies if your sentence was not intended to be a question, and my
response thereby confused you.

More generally, so that limits the number of people from whom you
might receive comments. It may be an appropriate trade-off, but I
can't make that judgement.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Wally said:

That sounds a bit weird, A possible issue with that is the way the steering
handles rotate, since the kingpins aren't vertical. They'd move in weird
planes. Using a normal bar and rose joint style linkages means that you can
control the plane the bar moves in independently of what the kingpins do.

It sounds weirder than it is! Catrike use it with great success, and
the range of movement required is low enough that the angles are not a
major problem. What you can do with the traditional linkage is adjust
the relative rates of movement so that small movements of the bars make
large movements of the wheels or vice versa. The disadvantage is a
great many more opportunities to add play to the steering.

Having briefly ridden a Catrike last summer I can say that it doesn't
feel that strange!

Jon

Ian Smith said:

Quoted message said:

So?

Quoted message said:

You suggested that you weren't certain whether it limited people or
not, so I confirmed at least one part of the apparent limitation.

So, when I said...

Quoted message said:

Quoted message said:

Comments invited, particularly regarding geometry and steering.

You added...

Quoted message said:

... but only from internet-explorer users.

You seemed to be implying that I was only inviting comments from Internet
Explorer users (which I wasn't), or that I would require reiteration of the
point you had just made above (which I didn't).

--
Wally
www.melodolic.com/IOTT
www.wally.myby.co.uk

Jon is Away! said:

It sounds weirder than it is! Catrike use it with great success, and
the range of movement required is low enough that the angles are not a
major problem.

Okay, I'll google on it and take a look.

Quoted message said:

What you can do with the traditional linkage is adjust
the relative rates of movement so that small movements of the bars
make large movements of the wheels or vice versa.

Yup.

Quoted message said:

The disadvantage is
a great many more opportunities to add play to the steering.

I already plan to use track rod end rose joint thingies to get an
adjustable, no-play linkage.

--
Wally
www.melodolic.com/IOTT
www.wally.myby.co.uk

Wally said:

I already plan to use track rod end rose joint thingies to get an
adjustable, no-play linkage.

I've got "track rod end rose joint thingies" on my Pino. They're about
5 years old now and just starting to show signs of wear.

<stupid question> Are they readily available in "BearingsRUs"?

Tim

Tim Hall said:

I've got "track rod end rose joint thingies" on my Pino. They're about
5 years old now and just starting to show signs of wear.

Quoted message said:

<stupid question> Are they readily available in "BearingsRUs"?

I'd like to think so. RS do a reasonable range of small, bike-sized ones.
About a fiver upwards for 'maintenance free' made with some sort of resin,
and a tenner up for steel. The resin ones weigh about 20% of the steel.

--
Wally
www.melodolic.com/IOTT
www.wally.myby.co.uk