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Posts in Category: Foam fairing

Foam nosecone 2 

I have two Black and Decker angle grinders. - I feel the Membership should know these things. - One is ancient and has now had the lead replaced because the wobbly plastick rubbishy bit that plugs into the back because Health-and-Safety can't countenance a person using a tool without there being fourteen levels of plug-in-ness to ensure maximum frustration (soldered, now, with lead-based solder which I gather can no longer be bought in Health-and-Safetyland) and minimum chance of electrocution because you can't cut through a live wire if the damned thing won't work. This has a wire brush on it because I am quite remarkably stupid and put the locking nut for discs down somewhere safe and cannot now find it.

The new one is a KG85 and I have just discovered this: that the front locking button bit thingy has been moved to the top of the instrument by some Stylemeister in the Marketing Dept. and you now need three hands to change a disc. Congratulations, Mr Black and Mr Decker. You may now step up onto the Rostrum next to me as Stupid Person Medal Winner.

(And while we're about it, why the *uck have you taken to calling your handtools 'Fire Storm'? Are the Buying Public that infantile? They're *ucking electric drills, for *uck'ssake. If you're into weapons manufacture for the American armed services then I can assure you that hopping about Afghanistan 3.7 metres from the nearest plug-in mains supply with a rotating 8mm drill bit is not going to have the Taliban heading for their caves, however sensuously you've created the bright orange plastic bodyshell. Which, for the record, is a considerable unimprovement because there are now no flat surfaces you can grip in a vice, you stupid, stupid dolt-heads.)

Anyway, back to the subject in hand. I am in receipt of further photos and it now appears Mr Knight has modified his concept of a foam bumper bar.


 

Gladwrap, if you spot the tell-tale yellow box under the new nose, is the Australasian equivalent of Cling-film. The final nose is of papier-mache, and I shall actually be seeing it tomorrow because Mr Knight is rather bravely going to set off before dawn and get here, we hope, in time to try it out on the track before the Rugby Football players take over Trafalgar Park for their afternoon's game. I shall then try to find out whether the Gladwrap is still in situ, and whether some waterproofing of the papier mache has taken place because if it hasn't we may be back to the bath sponge, since there is 'light rain' forecast for tomorrow in Nelson.  


Members who know Mr Knight will be concerned to see that the Ratracer has displaced the two penny farthings he normally keeps in his living room along with a pair of 28 inch wood-rimmed wheels. I have been in said living room and can assure you that the penny farthings are in the opposite corner. What this says about the saintliness of Mrs Bob Knight I leave to conjecture. 
 

Foam Nosecone 

Thursday, May 28, 2009 10:53:49 AM Categories: Bob Knight's fairing Correx corriboard corflute fairing Foam fairing
Bless my soul. Whatever possessed him to add a bath sponge to the front of his machine? When I suggested 'foam' to him I absolutely assure you I did not have this in mind. I mean I know he came to grief in Leicester but I'm at a loss to see how this can be prevented by this makeshift. This, Mr Knight tells me, is to replace the 'crappy papier mache' temporary nosecone he'd made. I think we may have to enquire further. It may be that he really has taken leave of his senses.
 

Foam fairing 

Thursday, May 28, 2009 4:32:06 AM Categories: Foam fairing

Right, here it is, freshly repaired. John Tetz, eat your heart out, because this is pure foam beauty. Well okay there are one or two slight blemishes but what in real life is perfect? The nose - well - truthfully - if I were given the choice of spending half an hour looking at the nose and half an hour looking at Allaneesha McHastings's - um - at certain body parts of Allaneesha McHastings (1) not normally on show, then it would be a close-run thing. Allaneesha McHastings since you ask is a forward young damsel from the girls' high school. As a matter of fact she came in to the local chirurgery the other day after a particularly energetic weekend's activities with a young man she'd met only two days before, and a person who we will not now name did spend half an hour looking at the aforenotmentioned body parts, and I divine that Allaneesha McHastings would have been a little more circumspect with her recreational enthusiasm had she known what she now knows about the young gentleman in question.

 

However we are not here to discuss Allaneesha McHastings's weekend hobbies: we are here to exhibit this superb example of a foam faired recumbent, and I'm sure I'll all agree with myself that it is very elegant indeed. When I run out of things to say about Mr Knight's fairing I may shed light on how it was made. I'm sure everyone's keen to know.

 

1. Allaneesha McHastings is not Amanda FitzHerbert's real name.

Workshop boots 

Wednesday, May 27, 2009 11:38:03 AM Categories: Foam fairing

We are now days away from the Nelson race, so I have to make haste and repair my fairing. Since foam is so wondrous versatile and I am easily distracted, here is a picture of my workshop shoes. Engerlish Readers, of whom admittedly there is little evidence, must needs note that May is November in New Zealand and feet chill easily in a workshop. The shoes were once Holey Soleys and are so amazingly comfortable that I had no difficulty in persuading myself to pick up flip-flops wherever I find them - and flip-flops are all about the roadsides here after the holidaymakers have made holidays - and glue them on the soleys of my holeys. But the holeys admit of limited insulation whereas foam is truly fantastick as an insulator. And so these foam-faired Holey Soleys are now (as Mr Larrington would have it) this thing: Warm. They are also tremendously stylish and when the children, who are all teenagers at the moment, have friends round, they greatly appreciate their father being seen with large blue foam pouffes on his feet.

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
25.1
25.3

Blue front fairing plus tailbox:
26.6
27.2
27.2

Blue front fairing only:
26.5
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
26.4
26.3

No fairings whatever:
25.6
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

 

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 http://www.wisil.recumbents.com/mars/pages/proj/tetz/projtetzmain.html 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.

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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