Amateur aerodynamics

[Jim Gerwing]

Tunnel vision

Yeah, refer to frame 22-26 of this thread. My wooden, paper, plastic fairing of last year gave me inadequate forward vision. So, without going to an optically correct, sailplane type canopy (an idea which I will hold in abeyance), I thought why not just leave a channel (the seeds of which thought are apparent in that red bike, previous page, your post).

 

[hamishbarker]

Looks like you'll have a good

Looks like you'll have a good view through there once the shaping is done.

The vector tricycles had a very laid back postition and had big clear canopy for forward vision, but I read that they were terribly prone to solar heating and/or fogging. your concept looks good, and a bonus is that the smaller radiuses of the foot bumps compared to a lightning f40 style front fairing might make the fairing stiffer and easier to attach to the main frame.

 

[Jim Gerwing]

The idea in general

 

[hamishbarker]

Looks great. The dip in the

Looks great. The dip in the middle skill also mean a nice short, (simple?) connection between the fairing and the top of the boom.

could be interesting to see if there would be much drag difference between this double hump shape add a more typical "torpedo" shape fairing by covering the dip between the knee humps with transparent film.

 

[Eric Winn]

I'm kind of worried about

I'm kind of worried about cross winds...

-Eric

 

[Jim Gerwing]

Nose job

After looking at the 'general idea', it occurred to me that I ignored my own advice appearing in frame 53 of this string. Therefore I have undertaken a modification of the nose lines which were circular and are now parabolic.

 

[hamishbarker]

How are you shaping the foam?

How are you shaping the foam? Just sanding or a coarse rasp?

 

[Jim Gerwing]

Cut, rasp, sand

For shaping I cut the foam as close to the final line as I dare then I coarse rasp, then I sand. The straight, long lines can be achieved with a long sanding bar. The aero-booties turned out very nicely by adding a light spackle, more sanding and the a couple of layers of watered down white glue. I'll have to do some research before attempting a fibreglass shell.

 

[Jim Gerwing]

Cross-winds

Yes, this is not going to be a commuter. I still bear the reminders of last year's spill (which was not due to cross winds but the addition of the front fairing was a factor). Low to nil wind and an extra-vehicular escort would be nice. But this is a low budget and flat organization so I will proceed with caution.

 

[Eric Winn]

I wasn't thinking commuter

I wasn't thinking commuter when mentioning cross winds but HPV streamliner racing. It doesn't take much wind to give those things a bit of a fit when racing around a track with the wind hitting them at all different kinds of angles. Or just traveling in a straight line but having the wind clock around during a run.

They are very fast however - when being pedaled like mad but also when they go sliding on their side down (and off) the track when they fall over for whatever reason. In fact, I was really surprised at how far those things slide when they go down... I'm talking the hard shelled variety, not the socked ones. If anything, the socked ones seem to have less trouble from cross winds because the sock yields a good bit to the wind instead of presenting a big and relatively flat freeboard for the wind to shove more strongly against.

-Eric

 

[Jim Gerwing]

Options

There are a few options open to me in a contingent universe: quit, proceed with some caution, add an anchor or arresting parachute, become a consumer of culture only not a producer, try some other restrictive or liberating alternative we haven't thought of yet.

 

[hamishbarker]

Eric, the hard shell does

Eric, the hard shell does allow for internal padding and abrasion protection though, at a cost of perhaps more frontal area .

Looks awesome Jim!

 

[KiwiGuy]

Radical!

Radical thinking Jim. My kind of guy.

Just take care out there...

 

[John Tolhurst]

In this approach I see

In this approach I see orthogonal thinking in tracing the air. Will it part left right, or up and down. I see a composite of shapes, as that is how it came to be. A question remains, what shape would it be if it one shape from the start?

 

[Eric Winn]

Fare in that center tunnel a

Fare in that center tunnel a bit and you would start to look a lot like this:



-Eric

 

[richa]

Blind spots


Not meaning to rain on your parade, but

1) This thing looks like it's going to limit your visibility considerably. The phrase "I didn't see what hit me" comes to mind...
2) Will your legs stay cool with no airflow?
3) I'm no aerodynamic engineer, but it seems to channel air down the center, thereby increasing the velocity of air hitting your possibly less then aerodynamic head.

It'll be interesting to see how it works out, but I think the "sailplane canopy" idea is better. I recall seeing info on some homebuilt aircraft forums several years ago about how to form plexiglass into a canopy. Seems like something well within your obviously capable hands.

 

[Jim Gerwing]

Orthogon

Sounds like a good name for the project.
Eric, where do you find those inspiring pics of beautiful moving art?
and, as per the title of this thread, this is an avocational quest (but it has it has a strange kind of hold on me).

 

[hamishbarker]

I guess the sculpting is fun.

I guess the sculpting is fun. would love to have a go at it too but I can't get suitable foam here in small town NZ (and then there is the question of how much time could be allotted to it after work and domestic duties (and sleep!). Keep the pictures coming!

 

[Eric Winn]

Jim, click on the Milan SL

Jim, click on the Milan SL photo above and you will see it is a Canadian product by a very talented countryman of yours.

I went the store-bought aero route and bought this:

This is a 2010 Bluevelo.com Strada serial number #010. Note that Bluevelo is also in Canada and quite close to me. I bought this from a nice fella named David who lives in Whitehouse, Ohio and rode it 80+ miles home to Brighton, Michigan. In case anyone is wondering, the yellow 16 stickers on my helmet are from this year's 2014 N24HC - I had completely forgotten they were still there but I've since remembered to peel them off...

-Eric

 

[super slim]

Eric do the flames make it go

Eric do the flames make it go faster???

What is the forward vision like?

How much faster is it (+5 mph?) for approx. the same power?

It looks VERY Aero, and will definately extend your cycling period into the snow covered winter.