‘We’ve built it. It’s down to Guy now’ GUIDE TO THE WALL OF DEATH Doors The key thing when de­sign­ing the doors was that we have to be able to get Guy out within 40 sec­onds. So we have peo­ple train­ing to open them as fast as pos­si­ble. The doors are de­sig

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Chris is a struc­tural en­gi­neer tasked with de­sign­ing the wall – he spe­cialises in un­usual projects. The tricky thing about de­sign­ing this is that there is noth­ing to go off. I vis­ited Ken’s wall, but it is a lot smaller and his rid­ers travel at a slower speed so the de­sign doesn’t trans­late to our wall. That makes it in­ter­est­ing be­cause we had to start from scratch. Here’s how we did it…

We were given the max­i­mum weight of the bike and rider (320kg) be­fore any­thing else. So once we had that fig­ure we could de­sign the wall and spec­ify ev­ery­thing to match. But first we would have to work out the max­i­mum wheel load us­ing that to­tal weight fig­ure.

The bike stays on the wall due to cen­trifu­gal ac­cel­er­a­tion (mass x ve­loc­ity, squared, di­vided by ra­dius), which gives us the G-force Guy will feel. We’ve upped it to 8.5G to give plenty of room. Us­ing that fig­ure we can get the wheel load by mul­ti­ply­ing the G by the weight of the bike and the rider, which equals 2.72 tonnes. Two thirds of that gives the max weight of one wheel, 1.8 tonnes. And then we’ve rounded that up to 2.3 tonnes to be well on the safe side. So now we have the max­i­mum G-force, weight of bike and rider and wheel load. So all we have to do is make sure ev­ery sin­gle point on the wall can cope with that pres­sure. We tested that out by us­ing a tele­han­dler fit­ted with load sen­sors to push against ran­dom parts of the wall and make sure they can all cope with 2.3 tonnes of pres­sure.

We know we can de­sign a wall that can take the forces. We tested the wall, it’s good to go. The big ques­tion is what hap­pens when Guy tries to ride it. It’s down to him now. We wanted some­thing large and bulky that al­ready ex­isted for the shell as we didn’t want to have to build a gi­ant frame for one show. I was help­ing my dad move

stuff into a ship­ping con­tainer when I re­alised that all we had to do was turn one on its end. So we used 48 con­tain­ers with two con­tain­ers with doors at ei­ther end for the shell. The front face is welded top and bot­tom and the back is tied to­gether with

con­tainer locks and stud­ded bar.

Struc­tural grade C24 soft wood. It’s strong tim­ber used in house con­struc­tion. Imag­ine those cra­dles you

stick un­der­neath wine bar­rels to stop them rolling away; we have a whole se­ries

of those that fit on to the base of the con­tain­ers to give them the curved form. Each plank is screwed down to them and to the con­tain­ers. There are no sharp edges. The more peo­ple stand­ing on the struc­ture, the more

sta­ble it is.

• •1.5 miles of wooden planks were used

Add up all the metal and it’s just shy of 100 tonnes, plus the wood...

It’s 3.8 times big­ger than the stan­dard Wall of Death used by Ken Fox If you go to Ken Fox’s tra­di­tional wall

you will feel it shak­ing be­cause it’s light­weight and por­ta­ble. This one is a lot more sta­ble thanks to the ship­ping

con­tain­ers tied to­gether in one big ring, mak­ing it in­cred­i­bly strong for the

higher speeds Guy needs to reach.

Ken’s wall is in di­am­e­ter while Guy’s has a di­am­e­ter, mak­ing it

nearly four times the size.

Most im­por­tantly, Guy’s wall can sup­port much higher loads. The forces on the wall will be dou­ble the forces

placed on Ken’s por­ta­ble wall.

Guy has two an­gles on the base. Ken’s has one 45 de­gree an­gle, which is fine if you don’t have to change speed of­ten, but Guy will have to reach 55mph

be­fore stick­ing to the ver­ti­cal wall so will need to build up speed more slowly.

The seat­ing has been ad­justed to cre­ate a sit up po­si­tion which is much fur­ther for­ward than on the stan­dard Scout. The sad­dle it­self has been re­placed by a 1920s Scout de­sign. The pegs have been ditched in favour of mid-mount

foot­plates. Bil­let alu­minium sec­tions have been used in place of the stan­dard shock ab­sorbers to cre­ate a tra­di­tional rigid frame. Ge­om­e­try re­mains the

same, just rigid. In­stead of one down and five

up, it’s now a race-pat­tern shift, so first is up and five are down. This makes it quicker

and eas­ier to change gear while rid­ing the ver­ti­cal wall. The front brake has been

re­moved so there’s no chance of ac­ci­dently grab­bing the lever. The back

stays stan­dard. Must be able to smoothly tran­si­tion onto the wall. A stan­dard pro­file has a bit of an edge to it, so Ken Fox shaped and smoothed off the edge of

the tyres with a hand-file.

The fork is now a solid down tube with all of the sus­pen­sion com­po­nents re­moved to stop sus­pen­sion bob caused by the

G-forces on the wall.

Ride, rest, ride again. It’s the only way to over­come the dizzi­ness Au­di­ence mem­bers on view­ing plat­forms will add ex­tra bal­last Up-ended con­tain­ers welded to­gether

If any­thing goes wrong, the crew can evac­u­ate Guy within 40 sec­onds Who needs the Large Hadron Col­lider when you’ve got this mon­ster Wall of Death? What makes Guy’s wall so dif­fer­ent?

Born into the trade, Ken has the wall in his blood 12 months of train­ing. This is no easy task Nor­mally bikes this old are mu­seum trea­sures

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