Aerodynamic aspects of an old GoOne 3 velomobile

[beate]

Yes, only the purple part. A full fairing around the back wheel cannot be built unless i might have succeeded with the stiffnes issue. And please note: the new back is based on the last attempt. Same length, but only a few and hopefully important details will change. See pics above.

[freebeard]

Needs context. Upside down, with the rear to the left? Where is the axle centerline?

"...parallel to the back plate..."? Tangent to the surface?

[beate]

This ist the wheelbox of the skeleton of the back i showed earlier (#25). Shown upside down. The dirt is the front, and the open back can be seen to the left. The top of the box had to be opened as well as i forgot to take into account the space needed for the suspension.

[freebeard]

So I take it that the pencil line in the picture is at the faint line midway between the [I-thought-it-was-Magneta] lines in the diagram?

Putting the road grime ahead of the wheel and less than full height? It looks like it collects in a pocket where further back air moving with the wheel sweeps it.

I don't see the benefit of halving the length of the tailbox. Less fineness ratio and twitchier crosswind handling?

[beate]

No, the length of the back will remain unchanges (except of 8mm on the left ower edge to correct uneven lenght)


Just making large holes into the part of the walls of the wheel box which did not get dirty. Like this start - it will be hidden by the cover of the skeleton. Purpose is to reduce weight - more than 2 kg is heavier than useful. If that will be an aerodynamic disadvatage i can still cover the gaps with strong paper (for parcels) which is still less heavy than those 4mm of poplar wood.

[The Toecutter]

kach22i's concept is beautiful and goes well with this velo.

I built my custom design out of coroplast in the kitchen of a former apartment I lived at. There was minimal mess. Working in a tight space was not easy, but it was doable.

Regarding rear wheel and derailleur/chain clearances, it would be best to make a prototype frame of the shell's attachment points first, before making the actual shell itself. That way, you can test for rubbing and clearances before going through all the labor of making a full shell, and if it doesn't work, you can modify it into something that does work. Get a basic frame design for the tail down that you know will work after testing it,THEN build the tail around it. Stiffening the rear of the frame is always going to be needed, given how much bicycle parts like to flex.

I ran into this same issue with the rear wheel cowling of my tail section.

[freebeard]

Stiffening the rear of the frame is always going to be needed, given how much bicycle parts like to flex.

I'm far removed from the subject, but [weird, twisted] logic would indicate that a tailbox that hinges coincident with the trailing arm would have minimal volume and could stiffen the suspension.

I'm thinking of a panted 4-bar double A-arm suspension. Where have I gone wrong?

[Piotrsko]

Originally Posted by freebeard

I'm far removed from the subject, but [weird, twisted] logic would indicate that a tailbox that hinges coincident with the trailing arm would have minimal volume and could stiffen the suspension.

I'm thinking of a panted 4-bar double A-arm suspension. Where have I gone wrong?

Too complex?

[beate]

Originally Posted by The Toecutter

kach22i's concept is beautiful and goes well with this velo.

Fully agreed, i even had considered something like that triggered by a similar idea from a DIY velomobile in my neighbourhood. With one exception: the shape of the back of that VM is pretty complicated as You can clearly see below (i thought it could be seen in the pics shown previously). The difficulty is always to integrate the lowest part of the body.
The other issue that lets me hesitate is that i am unsure to which degree it will be possible to stiffen the back. As far as i can tell there are also issues with the stiffness of the body near the joint og the rear fork. With some significant variation between each individual GoOne 3. Mine seem sto belong to the weaker ones. So the outcome of my efforts to improve the fork is uncertain.

I built my custom design out of coroplast in the kitchen of a former apartment I lived at. There was minimal mess. Working in a tight space was not easy, but it was doable.

I'm aware of that. I do actually have the possibilities to work with wood, and know what to avoid (sanding) and what to to instead (scraping)

Get a basic frame design for the tail down that you know will work after testing it,THEN build the tail around it.

That's actually whai i did, but sometimes You notice problems not unless You are driving hard. Which is waht has happened. And that carboard fairing was never intended to be more than a 1st attempt which cost me a just 2 Euros. The tail has definitely been made just for testing and getting experience with as little investment as possible.

For a final solution there remains actually a lot more to test: how much can i reduce weight? And: use relatively cheap material for the fairing. The paulowna wood is not too expensive, and it will allow me to proctice "stich and glue" / lute buildin techniques.

Stiffening the rear of the frame is always going to be needed, given how much bicycle parts like to flex.

But it'll still take a few weeks until its getting warmer again for doing any structural work on the bike itself.
[/QUOTE]

BTW: the available parking space limits the length of the tail pretty strict.

[The Toecutter]

If you attempted to put an image in your last post, it is not visible.