Posts in Category: Correx corriboard corflute fairing


Wednesday, May 20, 2009 10:12:22 AM Categories: Bob Knight's fairing Correx corriboard corflute fairing

Young Robert hath been busy. He hath been a-planking. (You may plank, in New Zealand: it is a verb. It is probably a verb in Engerland too, whereas Farewell is only a verb in New Zealand. 'Parliament farewelled Helen Clark' said the radio when she went off to be somethingorother in the UN.)

I have very nearly finished planking the thing with just about three planks left to do. I gave up for the night however because
a) it is cold in my garage in the evenings now
b) I've had enough for one night
c) I need to remind myself what my family looks like again.

Ingress is effected by his having pre-thought of the problem, and allowing two adjacent bulkheads, I think the plan was. I have to admit to admiring anyone who can pre-think of problems. Anyway, he then made an incision and lifted a lid out for the doorway, and I presume he has some Cunning Sch. up his sleeve to put it back on when he's inside. I am not yet privy to this scheme but you may depend the spies are out.

I'll be glad to get it finished because it really has proved to be a tedious operation; each plank consumes 30 minutes and there are lots of planks, I haven't counted them yet but I will tomorrow. I've needed to do a big push this week so that I can ride it with the fairing on tomorrow. I figure I will need at least two weekends inside the thing to gain some practice. I intend to use the road to Ashley Gorge (north bank) since it is long, flat(ish) only has a mildly shite surface, and most importantly is very quiet. I'll probably not have the cut out for the neck and arms done so I'll ride it topless tomorrow. I'll make a quick crappy nosecone prior to the ride. It will also be a good check that I can get it in the car. It's 2.6 metres and if I remove seats and things it should fit. Unfortunately we're meant to get the Nor' Wester tomorrow which is a bit of a bugger. I may need to get out early before it starts. Hefting it around in my garage, I've been surprised by the weight, it's a bit lardy now. Still, not too many hills at Trafalgar Park. - Bob

And here's the view from the cockpit:

NACA Duct 

Tuesday, May 19, 2009 10:46:46 AM Categories: Bob Knight's fairing Correx corriboard corflute fairing
Much erudite safety discussion between Senior Chief Scientifick Advisor (me, obv.) and Office Junior (Mr R G Knight Esq.):

Numero un. I'm sort of nearly finishing my foam affair, and want to reiterate that it feels really weird riding a machine where you can't see your feet. So if the NACA duct is still in the planning stages I want to say a word in support of making it big enough to peep through and satisfy your curiosity from time to time as to the number of teeth on your chainring. - R

1) yes I agree. I'll see what I can arrange with the duct when I come to do it. Possibly make the base of the duct from clear to give a line of sight down inside the fairing, ha, to see a computer as well. - Bob

Numero deux. Much worried by your spinning out at 64kph. That's 40mph. It is possible that you'll be able to hold higher speeds on the boring oval of Trafalgar park than on the open roads. What d'you think the possibility is of riding over 40 miles in this hour attempt? - R

2) not much I can do about that now. to be honest the thought of cornering at 64kph scares the willies out of me. I have nowhere to practise controlled cornering around here. I have tried to measure the radius of Trafalgar Park on google and compare with known corners around here but the corners on the roads here are not as tight. - Bob

Numero three because I can't remember the French. Hang on, Trois. When (sic.) you fall off at 40 mph, what will happen to the corriboard skin? Will it melt in short order and add excruciating pain to the scraped flesh? I know that foam has a very good protective effect when falling off at 25 mph because I very kindly performed this experiment some years ago. (Wet leaves. Sharp corner. Exuberant riding.) Rob English told me the Kevlar protected him when he went down at Battle Mountain. I can't imagine you'll want to be wearing sharkskins inside the fairing. - R

3) Corriboard is meant to be OK in a crash, but the skin will only be 3mm and possibly not even that where my arms are. Crashing also scares the willies out of me. Having crashed once before at 35mph I have no wish to do it again. I watched the Battle mountain crash on you tube and the kids and Steph saw it. We were a bit quiet for a while. - Bob

Numero four. Quatre I mean. There is a great big long thing in front of the front wheel pivot. Andreas Fuchs
warns us of flat sides wh. are esp. vulnerable to sidewinds. Great lengths of bodywork forward of the front wheel are also likely to make the thing sensitive to sidewinds. Ergo, is there somewhere/somewhen you can practise where there isn't any wind? Traf Park should be okay in the early morning for the run; I'm concerned about pre-race practice. - R

4) If I find the thing a handful, I'll just stop. Simple as that, I'm not risking my neck when I can do it again another day. - Bob

Numero five. (Bother. Cinq.) Foam for the arm-hole slits? - R

5) yes , I can envisage exactly that, I think it could work quite well. The pressure and lack of time on this is causing me much anquish. I do not like to operate under these condition. - Bob

Anyway, I was glad to see the duct appear, as it did, when the top planking started to get done.


First Ride 

Monday, May 18, 2009 12:50:45 AM Categories: Bob Knight's fairing Correx corriboard corflute fairing

Virtually all of this post is from Bob. In fact all of it. No virtuals at all. I have just done some strategic editing so that passing clergymen and social workers are not unduly disturbed by the use of certain concise terms.
As you can see much progress over the last week or so although not too much this weekend as I have just got swine flu or something, probably. I've been feeling very average this weekend.

I've been able to ride it up and down the garden in this state, although a worrying thing emerged. In order to fit into the fairing as it is, my arms and partickly my elbows have to be held very close to my body. This renders the machine unrideable. Tt seems you need that little bit of give to cushion the natural movement as you ride. If you are rigid it all goes very wrong quite quickly. It makes sense but it still surprised me. I think I will have to cut arm holes in the sides of the fairing so that I can still steer it. This will unfortunately make it less aerodynamic but will make it rideable at least and as a bonus it means I will probably be able to self start (maybe). Possibly I could cover the arm holes with lycra with a slit in or something.

I took it for another ride on Saturday. I did the full White Rock road again but this time I rode from my house since I'm more confident with the steering now. So another 50km of practise including the (deleted adjective) Ashley Bridge which is very scary on a normal bike let alone a low racer with dodgy handling. I also have to stop at right hand juntions and get off, wheel it over and restart when no cars are coming. I managed to average 39.1kph including the town and the restarts. Lots of very fast straight bits of road and on one stretch I spun out at 64kph. The handling is becoming more natural but I still worry about fast corners. On the way back into Rangiora I usually skirt around the town and come down West Belt (50kph limit) to avoid riding through the town. So I'm riding down West Belt at 50kph (it's slightly down hill) and a (deleted descriptive term for a person of whom the writer disapproves) in a car comes out of a side road from my left and slams on the brakes at the last minute. It's pretty scary when cars do that. He then overtakes me very slowly and indicates left and moves left whilst only just in front of me; remember I'm doing 50 at this point. He realises his error at the last moment and slams his brakes on whilst just in front of me. Now, I always thought drum brakes were quite good, partickly on smaller wheels, however I can reliably inform you that they do not stop you as fast as you sometimes need to. I stopped in time by mere inches. He then puts the car into reverse because he can't see me anymore and he's missed his driveway. Until I shout loud enough to get his neighbours out. His excuse? I was going too fast. (Another deleted term giving Mr Knight's views on the driver concerned.) Of course I'm now in a Very High Gear with a small audience, not fun. I'm believe I probably informed him exactly how scary the experience was from a cyclists point of view.

Fairing mounts 

Friday, May 15, 2009 9:27:31 PM Categories: Bob Knight's fairing Correx corriboard corflute fairing fairing mounts
Ye Olde Nexte Steppe is to work out how to mount the fairing. Mine get mounted on rubber exhaust bobbins from Sir Alexander Arnold Constantine Issigonis's Mini, which annoyingly have 5/16UNF thread or something, so when you grope about on the workshop floor for an 8mm metric nut it doesn't fit. Anyway the rubber bobbins allow things to wobble about and generally are an organic sort of thing and I recommend them, which recommendation I naturally assume everyone in the Entire World will now defer to, according me appropriate honours. (Sir Alec's FRS will do for starters, if you please.)


Mr Knight is troubled by the business of fixing something to an irreplaceable Burrows Ratracer which lacks natural mounting points and is made of a slippery bit of round stuff that you can't weld to. (To which you can't weld. Shut up, pedant.)

I've now got the top mounts completed and the actual spine complete. (The spine is 8mm corriboard which he reports is very stiff.) The mounts are bolted to the corriboard and then the whole assembly zip tied to the frame; there is a layer of the apple crate foam twixt frame and mount, they seem secure although a bottom mount down near the seat will be a must as you suggested. (See? See? at every stage the boy comes grovelling to me on bended kn. for advice admonishment suggestions sagacity and experience. )


And a side view:



Now starting to work on the ribs which should progress reasonably quickly. I'll make them all in cardboard first before I cut any more of the 8mm corriboard which is expensive.

Fairing Measurements 

It has now been established

1. that I know Everything and

2. that Bob Knight knows Absolutely Nothing Whatsoever and so he has to consult me, always, to find out what to do next.


Accordingly I guided him smoothly onto the next stage by sending him a Fantastick Pickchure of how I'm building my own fairing, which of course will be much better than his. My fairings are always of foam, because foam is stretchy and bendable and silent and protective in a fall and cheap (the stuff blows out of apple crates and litters the roadside in 4x8 sheets) and they are always incredibly beautiful. Well, more beautiful than Paul Lowing's tailboxes.

My technique this time is to use a cruddy old mount and jam a sheet of cardboard (bike box) on it and then glue thin strips of cedar to blocks of willow and thereby make a 3D mount which weighs nothing.

Mr Knight is entranced and impressed by this technique, which he has only ever used a great many times when a schoolboy to make model aeroplanes. Accordingly:

Attached photo is of tonight's work As you can see the big effort at the moment is to get the dimensions correct around the feet. I'm going to extend the top bit to include my knees and trim a bit off so I can ride it down the street and check clearance; so far so good. I think effort spent on this now will be tres beneficial since it will prevent rework later. I can *just* start off in the lowest gear with the 'normous chainring. I will need to do this a few times I think. - Bob

Possum bars 

Mr Knight who is a Low Creature and a toe-rag and a scumbag and a Foolish Person asked what to bring to New Zealand and instantly I replied 'a lathe' and being a L.C., t-r., s. and F.P. he ignored me and on arrival discovered how vastly clever I am because having grown up with one he really wanted a Myford Super Seven but such as appeared for sale were what engineers call Knackered.
New Zealand has a low population of lathes.
Yet being a guardian angel I magicked a Super Seven out of the ether in gloriously perfect condition. (In passing, Norm Milne of Stoke, the gentle old man who had cared for this lathe - old lathes never die - had preserved it in lanolin for fifty years from the salty Nelson air. Norm was a star of Nelson Model Engineering Club.) For the record it cost $NZ 1600, which since that's only about six or seven hundred quid is the finest bargain ever known among lathe owners. As I say, Norm Milne was a gentleman.
The following e-exchanges now took place. (We can record them accurately. Mr Knight lives six hours away. All discourse is by e.)

It now occurs to me that I will need a higher range of gears. I *think* my current setup is 53/12 on the rear 559 MTB rim. In all races so far this gear has proved sufficiently high and always gets used. Ideas? - Bob

Biggest one I've got is an unused 58 from a downhill bike. - R

Ha, so what BCD is the 58 chainring? 4 or 5 arm?I suspect that it is either 110mm, standard MTB or 130, shitmano road. The spitfire fund needs to know. - Bob

Il y a five holes sur il. Each hole est 65mm from le next hole. Stamped sur one side it says 'DH 58T BCD 110'. In other matters, my mother-in-law is a horrible old witch. But she's going on Friday. Either we shall be very, very sad to see her go or we shan't, and I'm not going to tell you which. I am going swimming now and will be bitterly disappointed if I tread on a stingray and get killed before she goes. R

Bugger fuck, because my crankset is a shitmano road at 130 BCD. I'll have to buy one and I didn't think 58 was big enough anyway and I bought a 55W glue gun and *lots* of glue sticks today for purposes of sticking corriboardcorrexcoreflutekoretake. Axshully that last one doesn't belong there, it's the Maori word for slacker, I have no comment on that. I made some little jigs last night to try to discover the bounds of whirring feet, but feet whirr differently backwards to forwards and I will need to make some adjustable do dads and go for a short ride to establish this. I also need to make the ratracer tiller steering since the widest point at the moment is the handlebars on full lock (which isn't much). This is turning into an ordeal already. I've just looked at Simon Sandersons pictures of his new streamliner. *Anything* we make is shite in comparison:
Warning: much time wasting could be spent looking at that link. - Bob

Therefore Mr K set up said lathe and promptly made some possum bars and a 64-tooth chainwheel.

The bars were to be welded up by Gavin Keats who is an aircraft engineer and who has built his own aluminium velomobile. This resulted in:

Now then young man, I feel I have been remiss in replying these past few days but I am busier than Talley's PR dept (1). I will try and recap.
1) Gavin Keats is going to weld up the bits for the tiller next Wednesday, that means I can install it very soon and see how bad the handling is, if bad I will ditch it and return to the original bars. In programming terms this is known as a ternary statement and in this case would be written like this:
_handlebars = ((_tiller == ridable ? _tiller : _original);
you didn't need to know that but I'm at work and that's where my head is right now.
2) I have started to make a 64 tooth chainring, this prompted by the shocking price of 'real' chainrings on t'internet. Cheapest I saw was 300 NZ lira dollars. No way. Going ok so far, I *love* my dividing head. I'm slightly concerned that the grade of aluminiumiunmium I have used is too soft, but then it only has to last an hour.
3) I have ordered my Coreflute Correx Corriboard Fluteboard from a plastic shop here in town and will pick it up at lunchtime, I've got 2 sheets of 3mm for skinning the thing and 1 sheet of 8mm + another of 5mm for the structure, think model aeroplane. That's how I did the tailfairing on the Windcheetah. I will experiment with hot glue later and see if I need to use dental floss and tape again. In programming terms this is also a ternary statement, an alternative way of expressing the statement is:
if (_hotGlue + Corriboard == strong){ _construction = _hotglue;}else{ _construction = _dentalFloss + _tape;}
but you didn't need to know that either.
That is all. - Bob

1. Talley's are a local firm who made the national news when it was revealed that people were perturbed to open packets of Talley's Frozen Peas and find then half-full of Black Nightshade berries.

Later, I had the following:

Possum[1] bars are *quite* hard to get used to at first. I rode on the lawn at first and crashed a lot, then began to get the hang of it a little, so this morning I took the Ratracer over the ghastly Ashley bridge and up to Carrs road which more or less goes straight for 19km right into the wop wops. It does wiggle a little and also goes up and down rather a lot as roads do, but because it goes nowhere it is very quiet. Anyway because I was new to the bars and occupying more of the lane than I really should I was taking it relatively easy at first. I averaged 38.2 kph for the 40km with a max of 62kph ( that's ~23.8mph and 38.7mph resp. in old money). The bars are decidedly twitchy and I'm having to learn to ride all over again it seems; however by the end I was able to pedal reasonably hard around gentle bends, but tighter bends had my sphincter all puckered up in an unseemly manner. This will probably ease. The 64T chainring was a great success and I was able to use top gear for extended periods over 50kph with no trouble as long as the road was straightish. I also seem to have a death grip on the bars at the moment; the handling improved when I forced myself to relax when I became aware of it.


[1] not hamster bars, possum bars. Relatively recently introduced and hard to control.


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