Aerodynamic aspects of an old GoOne 3 velomobile

[Piotrsko]

Ok so what happens with an airfoil like on a 737 max? Do they modify any of the flow, and does it make a noticeable, measured difference?

And where do you put them?

[beate]

George, before You continue, a few boundary conditions:

> length of vehicle. It is just limited to the current length.
Nothing more than, say, 2cm longer can be used
due to the parking situation.

> The back MUST be reasily removable for maintenance work,
especially the suspension strut which needs regular control
of air pressure. (I have replaced the old mechanical strut with
an air based Rock Shox Monarch RL.

This will also affect the electric connectivity -
there must be some kind of plug, and it must be easy to reach.

> i am living in a small one room appartment and do not have
the resources to make moulds for glass fiber or carbon work.

> my budget is really limited.
Especially thanks to the Corona politics in Germany.

That's why i am using an old velomobile,
meanwhile in its 15th year. I
If that limit would not have existed i would have ordered
a new Evo-R instead.

[freebeard]

737 max?

[citation needed]

First pass, sketched it up.

The skegs would be useful with a larger, slide-back canopy. Else I'd follow the VW NILS


'59 Cadillac backup light lens with RGB lighting. Virtual blue dots.

One minute delta.

> i am living in a small one room appartment and do not have
the resources to make moulds for glass fiber or carbon work.

Ask me about formless construction with sheet materials with darts or pie cuts.

edit: Aha! It's the Boeing Bird of Prey


www.pbs.org/wgbh/nova/xplanes/stea-nf

Morelli's Fiat used fans on the rear wheels to pump air into the wake. A plenum feeding a Coanda nozzle would be simpler. Also for cabin air.

[kach22i]

Originally Posted by freebeard

Ask me about formless construction with sheet materials with darts or pie cuts.

I'll ask for him, what do you have?

For me, I've worked with fiberglass before, and never used forms.

Kind of cheating but those Glass Microspheres (micro-balloons) allow for some easy fillets and curve blending.

https://www.youtube.com/watch?v=MXrfWvF470c

https://www.youtube.com/watch?v=jApI_YXDeGQ

Some thin bendable form-fold rigid insulation over a crude wood buck fiberglass epoxied over might do it.

If not then this?

https://endless-sphere.com/forums/vi...c.php?t=104731


If no work in apartment, then have a college friend 3D print something up for you?

Can you kitchen table work spars like a balsa wood airplane model? Then fabric over it?

https://www.youtube.com/watch?v=DNFcKuMQe0A

[beate]

Thanks for the tutorials.

Some thin bendable form-fold rigid insulation over a crude wood buck fiberglass epoxied over might do it.

Indeed, that'll probably be the final approach. In my prototype i actually went that way, but the card board i've been using as the skin of the prototype was not strong enough, and it reacted strongly even on changes in the humidity of the air. I should probably have treated it with epoxy. And that has intentionally been a prototype to gain experience.

The advantage of that prototype is that i can easily remove the skin and continue working on it.

Here the skeleton - it should be straightforward to improve the basic shape and to cover it with, for example, thin stripes of plywood like i did when i closed the canopy.



What i have learned: it looks as if i could extend th back again, at least a bit, to decrease the surface of the wake.

Maybe i could even change the angle again - the wood i cut off the initial prototype i still there, and a prototype does not require beauty where it is unvisible. And there is still a lot to test.

[freebeard]

I'll ask for him, what do you have?

Sheet materials come prefiinished. Normal practice is Zeppelin-like gores:

Compare the edges that need joining with this:





The edge length can be calculated mathematically to arbitrary precision, else they can be pick off a model with dividers. Each short cut creates a shallow cone. edges can be butt-welded or joined with an H-extrusion. Good practice is to drill the vertexes to create a stress-relieving hole.

[aerohead]

Originally Posted by Piotrsko

Ok so what happens with an airfoil like on a 737 max? Do they modify any of the flow, and does it make a noticeable, measured difference?

And where do you put them?

Are we talking about the upswept wingtip?

[freebeard]

You made more sense of the question than I. Like this?

[beate]

rough sketch of my recent ideas:



Which means that i will mostly keep the shape in the lower part of the back, but even out the curvature of the ribs. In the top part i decided to leave the back light free (for legality..). The silhouette was rising toward the back which i do not think is advisable - an early mistake by building the box, and a good opportunity to correct it.

I also plan to use planks from light wood (Paulownia) as the cover and run these parallel to the back plate of the velomobile. Which should be both optically appealing as well as easily to be fitted using a small plane.

Different issue - the wheel box within the back. The dirt pattern developing in the box shows large regions where i do not need any protection and can cut off a large amount of material to reduce weight. But how might that affect the drag of the wheel in the box?

[kach22i]

I found this old 2010 on that wood.

Palownia wood - better than Balsa???

New to me, sounds great.

So it's just the part in purple pencil outline that is being fabricated?

Should be just enough, I mean an improvement.

Maybe test it out and extend it later?