171.600MPH from a single cylinder Velocette at Lake Gairdner, South Australia..!!!

Wow....an email from Australian Velo Clubmember Stuart Hooper with the news that at the speed week trials on the salt lakes at Lake Gairdner in South Australia his supercharged single cylinder Velocette did 171.600mph.....
Stuart has set previous records at Lake Gairdner and also at Bonneville Salt Flats....

His email follows....

Hi to all,

For the first time in many years Lake Gairdner Speed Trials were unaffected by wet weather.  The surface was initially a little rough and the weather very hot requiring a careful eye on engine temperatures and excessively rich mixtures to ensure the engine survived the meeting. After a steady sighting run to check out the new body and steering geometry the Big Velo ran 166 mph on its second outing !!!!  This was good cause for celebration as the Velo was now the Worlds fastest British single surpassing the fantastic Vincent Might Mouse of Bryan Chapman.

 After a photo session day I decided a higher speed was possible and lined up again with a bit higher gearing and a higher ratio supercharger drive. The third run was only 152mph but this was against a 15 to 20 mph headwind so it was back in line for another 8 hrs for one final run. Friday morning was calm and cool, ideal conditions.......... but the morning ticked inexorably by with one delay after another and a headwind starting to flutter the flags and things looking like the meeting could be cancelled without another run. Finally the track was clear and the Big Velo boomed away from the line with its nearly 100mph first gear into a 7 to 10 mph gusting head and slight crosswind. By the time I changed up from third into top at 156mph the bike was weaving and darting about somewhat in the ruts on the track and the odd gusts of wind, but with the throttle hard against the stop one hand hovering over the clutch lever and the revs climbing towards the 6500 mark the track markers started to slip by faster and faster  until the final timing light flashed past and it was time to slow down with the old Venom single leading shoe brake smelling as only red hot 50 year old asbestos can. Back to the pits to see the crew flashing lights, cheering and jumping around !!!!......... 171.600 mph !!     .....  A fantastic end to a great week....... The Velocette name is again in the record books where it belongs !

Worlds Fastest Velocette.

Worlds Fastest British Single

Worlds Fastest Single Cylinder Sit On Motorcycle.

A sincere thanks for the support to my crew and all of you over the years,

Stuart Hooper

ps..... Just how fast can a Velo go ?

In the preparation for this attempt, Stuart supercharged the single cylinder engine and sent these photographs... 

Stuart Hooper, currently sporting the title of the world's Fastest Velocette for his foray last year at Bonneville has provided me with some interesting data under the title..."An exhausting day on the dyno"...

I've run several items on Stuart Hooper, a quietly spoken chap from just above Brisbane in Queensland, Australia who lets actions speak rather than words and the current holder of the title for his record breaking Velocette of "The world's Fastest Velocette"....

 Stuart accepts the Bertie Goodman Award during the 2010 National Australian Velocette Rally at Lennox Head, NSW from Anne Frampton (nee Goodman), Bertie's daughter and the Club Patron.
But in developing his Velocette record breaker, he has found time to be diverted into looking at the standard Velocette fishtail silencer used on the Venom/Viper/MSS and their derivatives...
Originally forming an article for the Australian Velocette OC magazine FishTailDownUnder (FTDU), which I've yet to use, Stuart was happy for me to pre-empt the article in FTDU with this post....

             An Exhausting day on the Dyno

My rally Venom has been fitted with a virtually dead stock engine..... So before I refitted my special squish engine I thought it might be a good time to get to the bottom of its long term lack lustre patchy performance. I fitted a new piston and cast iron barrel and carefully checked everything but the performance was still only fair.  A few days later it went dead flat and I staggered the 80 km home. After checking and changing everything to no avail and cursing somewhat, I aimed a disgusted kick at the silencer.....................and it rattled !!

Here at last was the problem...... I cut open the silencer and found the outer sleeve baffle had come away and jammed in the rear , choking the exhaust...... This baffle must have been cracked for some time and finally failed , and as the inner baffle on my bike is not attached to the pipe and had been fitted in various positions, this all conspired to give erratic exhaust effects, upsetting carburetion and performance. I fitted a plain pipe extension to scrambler specs and the bike went like a rocket. I was however curious (skeptical) about the efficiency of  the silencer so I decided to do some testing on my dyno....... here are the results, which I am sure will cause some interest.

Most runs were between 3 and 5000 rpm and all power figures are given at 5000 rpm.... at this RPM the engine is not stressed and is well on the cam a bit past peak torque and it greatly simplifies comparison, all runs were with a 30mm Concentric with 270 main, needle no 2 groove, slide 3 ½ ....these were found to be “universal settings” ....  A/F ratio fluctuated somewhat but was between 12.3  to 13 at full throttle so optimizing jets for exhausts was not bothered with but admittedly would have had some effect. Fuel was 98 octane, ignition adv 38 degrees, 17/8 cam, compression ratio is lowish at just a whisker under 8:1.

Velocette factory power figures were taken at the crankshaft with new well sorted and set up engines.... at 5000 rpm a reasonable 500 Venom engine should produce close to 30 HP at the crank .......The following figures are taken at the wheel ( where it counts ) so some power loss in the driveline ( chains, clutch, gearbox, rear wheel etc ) must be allowed for.

To establish a baseline the engine was set up on a straight through pipe 50 inches long.

Run 1.... 1 5/8” Straight through 50 “ ..... “scrambler”  pipe... 

no silencer.................  24.6 HP

Run 2 .... 1 5/8” Clubman pipe .... Fishtail .... baffle 10” protrusion in silencer .........  19.5 HP

Run 3 ....1 5/8” Clubman pipe .... Fishtail... long baffle bottomed in outer baffle......  20.2 HP

Run 4.... 1 5/8” Clubman pipe.... Fishtail ... NO inner baffle .......................................  23.4 HP

Run 5 ....1 ¾ “  Clubman pipe .... special low resistance silencer ...............................  23.9 HP

Run 6 ....1 5/8”   Clubman pipe ..... special low resistance silencer ............................  24.7 HP

Run 7.... 1 ½” Clubman pipe ...... special low resistance silencer.................................  25.3 HP

Approximately 30 runs in total were made, often going back to earlier setups to check repeatability and accuracy. .... NB..... The “universal carb settings” should not be taken as gospel for any other bikes..... final carb settings ,particularly the slide and needle, should be arrived at for individual applications by careful road testing, although significantly different settings should treated caution.

A couple of points.....I did some runs from 2000 rpm up and as a generalization there was not a huge difference in any of the systems up to about 3000 to 3500 rpm, but from there on it became quite distinct.. I was surprised to see the small 1 ½ “ pipe give the most power..... although the difference between the performances of the three pipe sizes was less marked when fitted with the restrictive baffled Fishtail and the effect of the pipe sizes may have been different at higher rpm...  No baffle resulted in reasonable top end but patchy mid range performance....Also surprising was the long bottomed out baffle being slightly superior to the shorter open baffle... The special low resistance silencer also gave considerably less fuel stand off from the carburettor. It is very apparent that when any baffle is fitted in these particular Fishtails the power is quite adversely affected. Varying the length of the 50” scrambles pipe was not tried, nor did I test megaphones or test at 6000 rpm, mostly I stuck to the 2500 to 5000 range......after all this is a two up rally touring engine and I was trying to optimize the setup for my own bike.  Road testing has confirmed the dyno results.

Both Fishtails in question are a common current reproduction type I see fitted to many of the Velos in the club..... I do not know for certain if they are exact replicas of the original, but from what I have seen in drawings they appear pretty close internally .... I do however find it impossible to believe Velocette fitted silencers as restrictive as those I tested , in fact I doubt a Velo fitted with one of these silencers could ever perform very well..  If anyone has a guaranteed original genuine article, I would love to test it. There must be quite a few bikes out there strangled by their beloved pattern Fishtails.

Here are a couple of photos .... one of the various pipes and silencers trialled and one of the offending internal baffles .

Dennis.... Perhaps you might have a good diagram of the internal layout of a fishtail...... I have also recently done a lot of dyno work on carburation and ram tubes etc .... I trialled five different carburettors , Amals and Mikunis  in one day ...and hopefully soon I will dyno some different cams so a couple of follow up articles may be of interest.

The Worlds Fastest Velocette....Stuart Hooper set a new record fastest speed this Friday for a Velocette..........

 Stuart Hooper hails from Buderim north of Brisbane, Queensland, Australia.

 For the last three years he has spent time and money attempting to produce a Velocette that is the fastest in the world.

He made the long road trip with friends as backup crew, some 2500km plus to Lake Gairdner in South Australia. 

Lake Gairdner is a salt lake where the Dry Lake Racers Australia hold speed record attempts early March each year.

Stuart's effort in 2008 was aborted due to rain washing out the meet with no racing occuring.

In 2009 he attained a speed of 133.46mph.

This year, 2010, late in the afternoon of Friday 12th March he increased this to 139.001mph, which eclipsed the 132.35mph that Bert Munroe achieved on his prewar MSS Velocette racer in New Zealand in 1971 and which was widely regarded as the fastest speed a Velocette had obtained under accurately timed conditions.

Congratulations Stuart.....

Keith Canning, President of the Velocette Owners Club of Australia and a member of Stuart crew filed this report to me tonight after he and Stuart returned to Queensland.
 

Australia has the Worlds Fastest Velocette. 

“What a week”.

I have just flown back to Qld from the salt at Lake Gairdner after a very trying but in the end rewarding Speedweek.

Stuart Hooper achieved 139.001 mph on the last day, Friday, only half an hour before the track closed for 2010.

The record previously set by Burt Munro in 1971 at 132.35 mph in NZ.

For Stuart & the team the week certainly had its ups & downs to say the least.  We arrived on Friday to find a perfect hard dry salt track, only to have rain fall on Saturday & Sunday. This was certainly a set back.  Once this happened no vehicles were allowed to be moved on or to the salt & the only access to the bike & trailer already in the pits was to walk through water stretching 100 metres along the edge of the salt lake.  Water was blown around the pits by high winds as well.

There was no racing on Monday, but with conditions improving, we changed the drive sprocket in anticipation of the track opening. 

On Tuesday afternoon we got a run on the test track where things went well.  It was the first run for the bike since last year as a complete unit.

After the drivers briefing we went straight to the GPS track where we achieved 133 mph as our highest speed.  With everything going well we then lined up for a run on the main track.  This enabled us to get a run on Wednesday where Stuart ran a licensing pass in the 125 mph range which is required because the bike had changed classes. 

Thursday was a big day with 3 runs.  The 1^st at 136 mph but with high cross winds forcing him to back off to control the bike.  The bike was literally tacking over like a sail boat & the back wheel moving out to compensate.  After this, Stuart decided to change to the small tail for the remaining runs. 

Our next run was a failure owing to the fact we had the wrong spark plug (warm up) in for the run.

 The 3^rd run resulted with Stuart being blown to the side of the track only missing the marker cones & backing off to stay upright.  He also thought the motor was getting tired, so after lining again till the end of racing to get a position for a run the following morning, we retired to our pits to thoroughly check the bike.

We striped the Velo to a bare machine, inspecting everything we could without dismantling the engine.  Things like the plug, bore, oil, timing, valve clearances etc.  Everything proved OK.  We raised the float level, and then went to bed knowing we only had 1 chance at most of getting a result for 2010.

Friday saw us line up early as racing was to finish about midday.  The day turned out to be perfect, no cross winds & very still.  We were confident of the bike now, but still ran the small tail, as cross winds usually started up at mid morning.  These never eventuated but by this time we could not change the tail.  We did however mix some new fuel & added 10% nitro to the methanol for an extra boost.  We changed to a larger main jet to ensure it ran rich & not damage the motor. 

The last run went well.  The bike ran straight as an arrow & was very stable.  It did run too rich however & missed & popped at the top end.  It actually would have revved harder on straight methanol.  Stuart ran & was timed over 2 miles.  He then had the long ride back to the pits, not knowing what we the crew, already knew.  He arrived to a jubilant team made up of wife Marsha, Russell Houghton & myself as well as anyone else who was nearby. 

Stuart would like to thank all for their support especially the crew, friends, well wishes, fellow club members & those who made the big effort to come out to the salt.

What’s next?  Develop the engine more & go faster, for sure.

I can tell you that when the Velo starts up, out on the salt, fellow competitors, crews & spectators all stop & listen to that unmistakable bark of the big single.  It’s music to the ears.

Keith Canning

 A beaming Stuart with his Velocette. 

 A special longer swinging arm fork was fabricated and fitted to the modified Velocette RS frame.

The bike in the guise it ran in the 2009 attempt. A more conventional dolphin fairing was used.

Stuart is shown on the salt during a run...

Some of the engine detail in the 700cc, 93.5mm bore by 102mm stroke, single cylinder Velocette "Venom" engine.

Including special cylinder made for it and the enlarged crankcase to take the larger bore.

Because the lake has a longer potential record strip, more and more US record breakers are coming to there as Lake Bonneville effectively becomes shorter due to salt mining etc.

Where is Lake Gairdner?

Lake Gairdner - South Australia

Home for the yearly speed Week of Dry Lake Racers Australia. http://www.dlra.org.au/

Site of the DLRA Speed Trials, Lake Gairdner is located in the State of South Australia. Largest of a group of shallow depressions west of Lake Torrens in central South Australia, 240 mi (550 kilometres) northwest of Adelaide, the State capital. It measures 100 mi (160 km) long by 30 mi wide. Lying at the base of the Eyre Peninsula, the lake is a dry salt pan (playa) intermittently filled with water. Visited in 1857 almost simultaneously by Stephen Hack and Peter E. Warburton, it is named after Gordon Gairdner, former chief clerk in the Australian Department of the Colonial Office, London.

How to get to Lake Gairdner

It is a very remote location, the nearest town of Iron Knob being some 121 kilometers (75 miles) from the turn off to the Mt. Ive Station.

Travelling time from the Victorian capital city of Melbourne is about 21 hours and Sydney, New South Wales about 25 hours.

It is about a 6 hour trip from Adelaide to Port Augusta. Most crews stay at the Big 4 Caravan Park at Pt. Augusta on the Friday night before heading out to the Lake on the Saturday.

Buy beer and remaining supplies at Port Augusta, there is fuel at Iron Knob, but no LPG. From Port Augusta to Iron Knob on Highway 1 is all good grade bitumen, this takes about an hour and is 68 k's. Fuel and supplies are available at Mt. Ive, but no LPG and at slightly dearer prices.

Turn right on the dirt road just after Iron Knob turn off, you then travel 121 km to Mt. Ive Station turn off, or keep going another 8 km, past 1 cattle grid, then you come to a creek sign, turn right just before the second cattle grid. It is then 21 km past the 2 gates (Shut the gate, mate) a water well, then salt.