Inexpensive "Bikini Fairing"

Joeblake
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Inexpensive "Bikini Fairing"

Postby Joeblake » Tue Jun 01, 2010 2:00 pm

After a couple of weekends I managed to make a fairing to stick on the front of my trike.

It's pretty inexpensive. The polycarbonate I'd had hanging around since 1993, the rest of the stuff consisted of PVC water pipe and fittings (had to spend about $15) and two large hose clamps, about $4.00 each.

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So roughly $30 or less. It's still a bit "wonky" as I've yet to finish "shaping" it. This is achieved by pouring boiling water over the poly until it softens then moulding it by hand to the desired shape.

Whilst it does bounce up and down a bit on rough roads, I'm able to pick the trike up by the fairing and it won't come loose.

Haven't worked out yet whether it actually improves performance, but the last time I put a fairing on my trike (1993) it added nearly a km/hr to my average speed. I'm going to see how fast I can coast down Welshpool Road. My best speed down there is about 78 km/hr.

It'll probably be hard to assess accurately, since this morning I also went up 5 teeth on the front chain ring.

I haven't glued everything in place yet, because I've not decided on the final shape, but it seems to survive the rigours of riding on the road.

Joe
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Re: Inexpensive "Bikini Fairing"

Postby }SkOrPn--7 » Tue Jun 01, 2010 3:55 pm

Joe that is a pretty effective job you done there and as long as it does the job then that is a great price for some MacGyver ingenuity. Tap a plug in the base then run a drink tube fill it with water and the fairing will also be a drink bottle.......... :wink:

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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Tue Jun 01, 2010 4:03 pm

It probably doesn't show up on the photos, but the "ends" on the PVC pipe which hold the fairing in place are actually screw threaded into the pipe, so it's already capable of doing the "Gunga Din" trick.

:mrgreen:

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Re: Inexpensive "Bikini Fairing"

Postby }SkOrPn--7 » Tue Jun 01, 2010 4:38 pm

Of course now I look closer Joe I can see so those things that look like shock protection as the pipe passes through the Poly is that just jammed into the 90 degree fitting and the threaded fitting is wedged in? I had to laugh at the "Gunga Din" I haven't heard that expression used for a long time your showing your age there Joe and I'm sorry in advance if your young it's just that not many of the young ones would ever hear the old saying now a days. :D

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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Tue Jun 01, 2010 5:44 pm

60 years old and proud of it. :mrgreen:

There is actually a thread on the end of each of the 90 degree elbows to take the plug. Sadly I had to really mangle them to get them to fit, by cutting the plug back quite a bit, otherwise it wouldn't have gone in tight enough to press against the poly. I've used scraps of leather to act as a bit of a washer. The last fairing I actually managed to find some "hex headed" plugs, and I'm still searching to see if I can get some. They give a firmer grip against the windscreen.

Joe
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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Tue Jun 01, 2010 5:52 pm

Went down Welshpool Road and back up Crystal Brook Road. Maximum speed indicated on the computer 78.9, but the big difference was once I hit the flat at the bottom of the hill I was able to crank the extra 5 teeth a bit, and I kept going (for about 200 metres) at about 45 km/h, which is about 4-5 km/h better than previously.

Averaged 16.3 km/h over 12.93 km. This is nearly 2 km/hr better than previously, but of course both figures are motor assisted.

So in a very unscientific fashion I've altered 2 variables and can't arrive at a definitive answer. :lol: :lol:

But I think the fairing does give a wee bit of performance enhancement. :lol:

Joe
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Redbull
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Re: Inexpensive "Bikini Fairing"

Postby Redbull » Tue Jun 01, 2010 6:46 pm

Just remember Joe that PVC can splinter on impact and most pressure pipe is not UV stabilised (and the DWV that is isn't worth wondering about).

That could be a nasty accident waiting to happen if you hit anything (especially as it's aiming right up to the Jatzs :shock: )
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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Tue Jun 01, 2010 7:19 pm

I've had many years of building with PVC. One of my first projects in 1997 was a geodesic dome which stood exposed on my bush block (at Gidgegannup) for close on 12 years and was still able to spring back into shape after being distorted by a violent storm.

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It's great stuff to play with.

I've tried all sorts of tests over the years (including using some of the stock I purchased in the early '90s) and the only way I've been able to get the pipe to shatter is by freezing it at -15oC for 24 hours then hitting it with a hammer.

In any case, the polycarb is more likely to crumple and absorb the shock.

And by using glue on only some of the joints, (theoretically) any impact will cause the joints to fall apart, a sort of mechanical "fuse" if you like.

Joe
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Re: Inexpensive "Bikini Fairing"

Postby Storm » Tue Jun 01, 2010 10:50 pm

Joe Blake I also made a fairing from flat polycarb for my swb in an effort to increase my speed but I didn't find that it made me any faster, it did a good job to keep the rain and cold wind off my legs during winter tho:D


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Joeblake
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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Tue Jun 01, 2010 11:01 pm

Looks pretty good. I don't how mine will go at keeping the rain off me though. My next thought is to try and make some kind of lycra body sock.

How did you join the polycarb at the bottom of the cone?

Joe
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Re: Inexpensive "Bikini Fairing"

Postby Kalgrm » Tue Jun 01, 2010 11:34 pm

Try a tailbox: they have more effect than a nose cone because they reduce the turbulence you drag along.

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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Wed Jun 02, 2010 12:06 am

Errr .. sorry, got me photovoltaic panels back there. :lol: :lol: :lol:
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Re: Inexpensive "Bikini Fairing"

Postby Storm » Sat Jun 05, 2010 12:52 pm

I made small holes along the lengths with a soldering iron and thread fishing line like a shoe lace, at the bottom I riveted an alloy bar to open the "mouth" a bit (it would be better if the bottom was also connected to the BB).
where it comes to a peak it needed some heat to aid its tight bend and not crack. The fairing works well and it's nearly time to put it back on :wink: I will probably make a new one for my LR too.
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Re: Inexpensive "Bikini Fairing"

Postby Storm » Sat Jun 05, 2010 1:15 pm

BTW do the PVs wok well?
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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Sat Jun 05, 2010 1:49 pm

I suppose "work well" is a relative term. :lol:

All they're supposed to do is keep my batteries "topped up" while I'm not riding, and also to make sure that when I ride down to Perth I've got as much power as possible to ascend Welshpool road. Since I scarcely use the motor of the flat they do the job quite well. In theory they're supposed to generate 2.5 watts of power each, but they're getting a bit old now.

When I made my first fairing I shaped it with hot water, used a hot awl to melt small holes along each side of the gaps I had, then stitched it together using nylon cord and used Araldite along the seam to cover the holes and the stitching.

Joe
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Re: Inexpensive "Bikini Fairing"

Postby Storm » Sat Jun 05, 2010 9:09 pm

I've been looking (AT) your dome some more Joe and it really impresses me how cheap and simple it is, did you also lace the ends inside the junctions? Where is a door and What did you use as a cover?
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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Sat Jun 05, 2010 10:04 pm

You can see an exploded demo of the "hubs".

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The "safety pin" (made from fencing wire) is used to hold the struts in place. The smallest diameter PVC pipe was supposed to act as a "foundation" for the struts to push against under compression. However, once I had the dome actually assembled it dawned on me that there was NO compression anywhere, as all the foundations kept falling out, and I had to hold them in place with fishing line, which you'll see (faintly) in the first photo.

There's no "door" per se, but once the dome is assembled one of the horizontal struts on the first row can be removed without affecting the structural strength of the dome too badly. This gives you a "diamond" shaped doorway.

For covering, I used several different materials. The photos show the initial black plastic sheeting which was just tied in place with nylon cord. I later made a cover of impervious plastic green shadecloth, consisting of triangles the same size as those of the frame cut and taped together so it fitted very closely. Some of the panels had roll up "flaps" with insect netting inserts. Unfortunately, I wasn't able to do what I had planned and that was sew it together, and the tape didn't last past the first big storm. HOwever, the black plastic came and went over the years, and whilst I had initially built the dome with the intention of using it as a cover for my motorcycle, fixed by hinges to the ground so it "clamshelled" upwards, I'd ride the bike in, and drop the dome back down and lock it, it became a sort of "home away from home" and I used to sleep overnight on the weekend.

The guy ropes in the first photo were actually holding the cover in place, rather than the frame. It's hard to see but I had a bridle rope and tent pegs on the inside of the dome going over the first horizontal row of struts. Once that was in place the dome did not shift for well over 10 years, until I disassembled it.

I've now got a "sewing room" so I'm currently working on a bigger dome frame, using a different construction technique.

Image

The principle is that since the dome is entirely under tension, and not compression, it doesn't require the foundation for the struts to rest on, and using the little collars this spreads the tension onto two rings of PVC pipe.

Another upside of this technique is that I don't need to assemble the hubs "on site" as I did with first one. It took me well over a day to put the first one together because the hub foundations kept falling out.

My first dome was strong enough that, by carefully distributing my 100 kg mass from several hubs (about 6 from memory) it would support me.

One of my reasons for getting involved with geodesic domes was that given that I could find suitable material it could be possible to build a light but strong geodesic frame which I could use as a fairing shell for the trike. I'm still looking for "the right stuff" though. :lol:


Joe
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Re: Inexpensive "Bikini Fairing"

Postby just4tehhalibut » Sat Jun 05, 2010 11:47 pm

Joe, that's a nice job and I wish you well. However I have a Mueller Windwrap fairing (http://www.mueller-hp.com/trikes.htm) to suit a Greenspeed trike, this starts like yours over the footwell but comes up to about neck-height and back past the knees, so the style is a lot larger in fairing/coverage. I had to make the actual mounts myself but they're effective, I did an 84.5km/hr bomb down Lesmurdie Hill on 2006 with this setup. Then I haven't used it since (but then I've got excuses).

If you want to compare I'm happy to loan it to you for trials or you might at least have a look at the mounting system. Also, my fabrication skils are improving, if you want I can help you make a metal mounting for your own gear. I've got a couple of metres of white coroflute somewhere, although I don't think that you'd want a front fairing of this. You have a trike and live on top of the hill that I'd been using to fairing tests, lucky you.

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Re: Inexpensive "Bikini Fairing"

Postby Joeblake » Sun Jun 06, 2010 1:15 am

just4tehhalibut wrote:You have a trike and live on top of the hill that I'd been using to fairing tests, lucky you.

:lol: :lol:

AND I've got an electric assist to get back up again. :mrgreen:

Thanks for the offer. The Windwrap looks like what I had in mind originally. Digging around in my shed during the week I found another quite large piece of polycarb from my original supply I'd forgotten I had. I've still got a few more ideas to try out as yet, so I'll work on them first.

My fastest descent is 87 km/h going down Gooseberry Hill* road on my unfaired SWB Greenspeed bike. I might try mounting my bikini on that some time. But I'll have to pedal up under my own steam. :lol: :lol:


Joe

*Before they put the Roundabout at RidgeHill Road in.
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