Colonial Diaspora

Trial run 

Thursday, May 21, 2009 10:35:51 AM Categories: Bob Knight's fairing Correx corriboard corflute fairing
From Mr Knight:

Took the ratracer around Ashley Gorge today. It's a 75 km loop from my house and features lots of long flat straights at either end and some fairly steep hills at the middle gorgey bit. 64/25 is just too high for hills like this. However I still averaged 37.6kph with a new max of 71kph which feels quite fast enough thank you with my arse mere inches from the tarmacadam. Which incidently varied from OK to utter, utter rough shite (with tree roots as well). Still worried about the handling on the track though. The natural speed on the flat appears to be 43-45 kph. The wind of course changed from a headwind out to a headwind back. I got a bit more planking done the afternoon, but I fear I will need to tape the seams as well as glue them since glueing thin correx is quite hard to do before the glue cools too much. - Bob

I am unclear as to whether he took the fairing with him or not but that's because my Inbox is a confused mess and you don't need to tell me I ought to tidy it, I already know that. Anyway the planking is very pretty but then I knew it would be because I have the gift of prophesy. Here, since I happen to have it to hand, is a picture of a shady pictureskew garden somewhere in New Zealand.


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:

Foam roll-downs. (Or rolls-down if you prefer.) 

Wednesday, May 20, 2009 8:47:00 AM Categories: Foam fairing Roll-down tests

Anxious to Compare and Contrast, I took the newly built, but not yet photographed (a mistake as will be seen) fairing to a certain hill I know and love, and did roll-down tests before the forecast rain that didn't happen. (The above is of the tailbox only, which information I include for those who imagine I pedal backwards. My tailboxes have been huge ever since a conversation with John Lafford, who (I'm summarising) said 'Make your tailboxes huge'.)

Tailbox only:
25.2 mph

Blue front fairing plus tailbox:

Blue front fairing only:
then I got my cleat stuck while stationary and fell over and snapped most of the wooden slats inside the fairing and cut the top off my little finger on an errant bit of sharp road

No fairings whatever:
25.3 with my RH on the handlebar extension but my LH over my chest
26.0 with my RH on the inner part of the handlebar and my RH over my chest

all of which took exactly one hour.

Then a strange man came wandering over from the adjacent field, stubbly (the man, not the field) and dribbling a little, with an elderly shotgun lodged in the crook of his arm. Whereupon I felt I ought to speak to him to explain what was going on.

I said 'I'm just testing different fairings on a recumbent bike because when each is changed, the hill gives me clear results' and the stubbly man said 'Clear results, that's right' dribbling a bit from the corner of his mouth. I said 'I roll down the hill to see how fast I get up to on my computer.' The man said 'My computer, that's right, mm,' and I thought this is strange, he is unable to compose and speak a sentence; all he can do is repeat the last two words I've said. And then I started to think that this is going to be either the most interesting or the most uninteresting conversation I've ever had in my whole life so just to see which, I continued: 'First I put the tail fairing on and roll with that, and then I add the front fairing, and then I see what difference it makes.' 'Difference it makes,' said Stubbly, dribble dribble. At this point I wanted to hug him for having survived for so long despite being completely and wholly stupid but then I began to think of those horror movies that used to come on Channel 4 on a Thursday night where a Perfectly Innocent American Person goes into the woods and meets a Strange American Person Who Already Lives There and all sorts of unpleasantnesses that I'd rather not remember ensue. So I hurriedly set off in a southerly direction and was swiftly followed by a volley of shots.

(Okay. Maybe some of this is untrue. Maybe I just wanted to add a bit of colour to an otherwise bland account. )

So we can conclude that my fairings are rubbish, if we are to be honest and objective. And I wonder if this is partly because of the large hole - well, the non-floor - which creates colossal drag. Neglecting the hideous knobbly shape. Pictures will have to follow when - if - it ever gets repaired. Anyway this provoked the following angst-ridden exchange:

Uh? It seems that the tail fairing on its own makes no difference, indeed possibly a minor decrease in speed. The front fairing does make an improvement. The front fairing + tailbox is even better. Do you concur? I'm impressed that you can take a hand off whilst riding. There is no way I can do that on the ratracer. It is *pissing* down here at the moment and I am sat sitting here on my stool in a medium sized puddle having got thoroughly drenched on the way to work 'smorning. I've just read the paper and it gleefully reports a big depression that will cause a lot of weather later this week and at the weekend. At least I'll be able to get some planking done on the fairing. Incidentally I threw a sheet over the frame last night to get an idea of the shape and I was surprised how large it is. It is 20" wide at the widest point and this looks enormous. - Bob

Whenever I've made fairings, front and rear, 's orlways been the same. The tail adds *at best* half a mile an hour, the front adds about a mile an hour, and both together add a further half mph. But my level-ground racing speed is too slow for the tailbox to collect separated flow and reattach it. My brother tells me that his recumbent motorbike tailbox is very significant. Mind he does have a very good front fairing too. Implication of Hucho (p311) is you need a big rear section and a fairly high Reynolds number before air re-attaches once it's separated. I forget what my Reynolds number is - I worked it out once - but it was significantly less than the lorries Hucho was describing.
The present tailbox in earlier roll-down tests gave me an extra 0.36 mph at 23/24 mph. This is a whisker less than I had expected, but even so I was surprised by the result showing a reduction in speed with the tailbox. To be statistically valid, I need a *lot* more trials but they take a huge amount of time to do, and as the morning wears on the wind gets up so you have to stop. One problem is that I notice myself tensing, even during a roll-down, and when I relax I go faster. This *might* be because I flop lower down in the seat when relaxed, but there may be other reasons that I haven't figured out yet. I do know the gain is small, and it's also highly variable between runs.
In Engerland, fair Engerland, there was a hill outside Barrow on Soar which after a gentle slope getting me to 20 mph and holding it there for a good steady 200 yards where I could read off my (realistic) road speed, then dropped away to a valley floor where I hit 30mph before slowing up on the other side of the valley. The impact of tail fairings was much bigger at the higher speed.
Example: Paudy crossroads to Walton, 13.12.97.
MWB touring machine with large foam tailbox: 21.5 mph, max at bottom of hill 30 mph
Same with tailbox removed: 21 mph, max at bottom of hill 28.5 mph. - R


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.


Driver Error 

Tuesday, May 19, 2009 1:20:33 AM Categories: bike crash
Driver stupidity is a factor that we prefer to ignore but shouldn't. Rob Hague, I vaguely recall, was once arrested and interrogated for assaulting a woman in a Range Rover from the safety of his Greenspeed Trike. - Don't try this at home, because if you attack a Range Rover while seated in a Greenspeed Trike the Range Rover might win. Rob Hague, of course, is sixteen feet tall and weighs eight hundred pounds and has the Speaker's Mace, in iron and twice as big, attached to his wrist so when he assaults a Range Rover the woman in the Range Rover comes off worst and has to go crying to the Police about the matter. (Actually it is possible I have made a mistake: it is possible that the Range Rover Assaulted Rob Hague, but swift reporting by the woman driving the senselessly oversized vehicle seemed to have prejudiced the Police's views on the matter. And maybe Rob Hague isn't as big and threatening as I've made him out to be.)

Anyway, John got knocked off his bike going to school today. Stationary in the middle of the road about to turn right; woman coming onto the road from the left didn't see him through the pillar of her windscreen. She was horrified and brought him home uninjured, with slight munting to the bike, but the derailleur hanger's bent and the derailleur may be and his saddle's thoroughly scraped and so's the rear rack and the pannier was all scrunched up and busted inside and his rucksac (inside the pannier) has a busted strap clip. I now have to persuade the Police to take no action against her, because I can't see that it would do any good. She was very contrite and volunteered to make good all damage, and I think she was just mighty relieved he wasn't hurt.

As I say, driver error is something we need to allow for, at least until I am given authority to control motor vehicle driver licensing with a .303.

The Foam Rival 

Monday, May 18, 2009 12:57:42 AM Categories: Foam fairing
Now because Mr Knight is but a youth, a stripling, he has strength and vigour on his side. Accordingly my fairing has to be far better than his, and this is easily accomplished by dint of my exquisite craftsmanship. (I am not so foolish as to attempt the NZ Hour Record, however.)

My notebook claims this handsome khaki fairing sits on my fourteenth bike but I wouldn't be deceived by that because several of the marques were complete rebuilds of existing machines and some were but frames which got handed to distant cousins for completion. Anyway I think this was taken in 1997 and it shows the foam fairing made out of Pte Cruikshanks's ex-army foam carrymat which I bought for the sum of four pounds fifty pence from Anchor Surplus of Nottingham and since Pte Cruikshanks's was only of ordinary size, several other soldiers' sleeping mats as well but they didn't write their names as boldly or even at all so I don't know who they were.

This foam is 10mm thick and it glues readily with Evostick or whatever other contact adhesive you happen to patronise. My favourite was Thixofix. Sixothix. Fixothix. I never knew what it was called and only enjoyed it because my father-in-law spent his last years trying to pronounce it without any success whatever. (He was Hungarian.) You can obtain it for free by walking round the back of the Derby Road Gate of Wollaton Park in Nottingham and mugging one of the glue sniffers. Spherical curves are obtained by snipping bits of foam out and tugging the edges together and the contact adhesive sticks the bits to your fingers, mostly, and you have to do a whole bout of washing up to soak it off.

I imagine someone has Youtubed this technique but the children use up all our Internet access on pirated episodes of the Vicar of Dibley so I can't check. This particular fairing - I said it was handsomer than Paul Lowing's - was free-standing with the most minimal framework and though it allowed free tearing during a race (the pic was taken immediately after Curborough one year, and the square flappy bit is where I hadn't *quite* allowed for heel clearance), it was quite difficult to build without a mould.

Anyone with half a brain will consult John Tetz but fancying I could manage with framework rather than a mould, I consulted Bryce Day (that's his name) who made our kitchen and whose parents made all the coffins for Motueka and who had the Funeral Business and gave us and likely everyone else a fridge sticker with 'Have A Nice Day' on it. They really did.

Bryce erroneously thinks I'm a loony so he hurriedly gave me access to all the cedar offcuts in his skip to get rid of me, and as they're 2.2mm thick and 26mm wide, they bend very easily and all you need is a scrap of double-thickness corrugated card, such as is obtained from a bike box, as your gluing template. Bend and periodically introduce a spacer and bind the glued joint with a strip of rubber inner tube and you have extravagantly light-weight curved frames.

When all is done, glue them together and sit inside and pedal and see if there's toe clearance. It requires no plans at all, and is fun to do, provided you're addicted to glue, which may well be the case if you live near Wollaton Park.

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.

Engineering tribulations 

Friday, May 15, 2009 11:37:45 PM Categories: Bob Knight's fairing engineering problems
Today le chausseure est sur l'autre foot, as a Frenchman would very probably say if he knew what it meant and also couldn't remember how to say pied, because I am very reluctantly forced to seek Mr Knight's engineering opinion. Mr Knight's father was an engineer as was mine, but Mr Knight Snr has the advantage over Mr Middleton Snr in that he's alive. (Axshually I generally contact my brother who's yet another engineer and who gave me 'zackly the same information only quicker, but this blog is currently dedicated to the Daring Exploits of Mr Knight.)(Persons wishing to see what my brother gets up to in his spare moments have to Google 'Arthur Middleton FF' where they will be dismayed to find that he uses large engines in his recumbents.)


Immediately tell me how to fix my micrometer which I am disconcerted to see is whicked (1). It's a Starrett, and as far as I know was always fine. It measures 0 at the 0 setting, but 9.99 on a 10mm Guering drill shank, and 3.97 on a 4mm drill shank. This mis-measurement seems consistent on all the drills I put through it including brand new ones. - R

That's because drills are not accurate. My father chided me for doing exactly that, measuring drill shanks - even really expensive ones aren't. I suspect that your micrometer is fine, but to properly test it you need to get hold of some test pieces to compare. Some micrometers have them included; most don't however. Alternatively measure some silver steel which is ground to fairly precise tolerances. Lots of progress on the fairing this weekend, pictures later after I had me tea. - Bob

We assume 'e 'ad 'is tea because later in t'evening came the following:

I tested the hot glue on the corriboard and if I leave the glue gun for a full 5 minutes, I'm then unable to break the glued joint. It is very strong. - Bob

There followed some gluing, resulting in an encouraging development and if I could be bothered to go and consult my book on aeroplane fuselage construction I would use the Correct Term. As it is the photo will have to do:

Next young Mr Knight learns something about seats, which I being just Wonderful had already told him but he being Stupid had dismissed as irrelevant:

I extended the top temporary fairing to cover my knees and discovered that I needed an extra 5 mm for comfort. So that was handy. I also discoverd that I will need to put in a lumbar and a neck support to maintain the correct position, since slipping just a little makes a difference to the clearances. - Bob

In fact it was a Foreigner who told me about the neck support and I wish I could remember his name but it was at least ten years ago and my Brane is week and feeble with age. Anyway what this is is this. If you support your head then your brains get jiggled and eventually fall to pieces inside your skull. If you can somehow support the base of your neck to keep it upright, then the head balances nicely on top of the neck and less brain jiggling takes place.

However more tribulations were on the way:

Whatever possessed my wife to light a fire in Maud without putting a four-inch piece of industrial hacksaw blade in it? So now just before bed I have had to sacrifice a large handful of twigs in order to get it red hot and allow it to cool overnight. Sometimes I really wonder if she has a brain at all. - R

OK, I'll bite. So why do you need an annealed 4" peice of high carbon steel? What zackly are you making?- Had a fuck up last night, I cracked one of Gavin's welds on the Ratracer steering. I'll put a frankenbolt through for now and get him to reweld before the race. Other than that, just panicking that I don't have enough time left to finish the thing. - Bob

I never did tell him why I wanted a piece of annealed high carbon steel, and I don't propose to tell you either, mostly because it adds an air of mystery to the proceedings. I'm not going to tell you what Maud might be either for the same reason. (Axshually Maud is the name of one of our sheds. We have sheds, in New Zealand, and a good deal of scenery, and an awful lot of weather, and quite a few earthquakes - there was a little one last night - but not many people.)

1. Whicked. A New Zealand spelling. The Wh is pronounced F, as in Whakarewa Street (pr. Fucker-reewer Street. - No, that's true, and it's where the children's High School is). The i is pronounced u, as (famously) in Fush and Chups.

Another useful New Zealand word is 'munted.' I very much doubt if I will be able to complete this account without using it.


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
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