200 naked

[hawkwind]

I remember well 2004 when the race was on for the first bike to break 200 in Aus .... move forward to 2014 and I expect the race to 200 for a naked bike will be on ... it was almost reached this year ,infact I expected it to fall ,but not quite .... 3 riders were knocking at the door.......
Ronnie Stayte 198.4 .... M-F/1650 ........ Chris Bryson ....198.2 .....A-F/1350 and the Greg Watters /Jim Higgins team .....192.1......M-BG/1650......looking through the results there are 13 potential candidates .......Eve Scholz has already broken that in the USA with 215 M-BG/1000 and should be there for 2014.

Though we are quite a ways behind the US teams 226.8 M-BG/1650 ....... 226.02 A-BF/ 1000........224.58 A-BF/1650 ...... 221.5 A-BG/1350...it just goes to show that this is the hardest way to get to 200 bar none.

I hope to be joining the race ,so to all those prepairing break a leg

Cheers Gary

[Greg Watters]

Jim said the 192 here felt more like 230 over there , thicker air nearer sea level makes it a lot harder
The SCTA 224 A/BG1650 is Neill, DLRA 1048
hope to see your name on one of those records Gary

[Stayt`ie]

At Bonneville there have been a number of "Turboed" bikes, and a handfull of "Old Skoll" (Vincents, Triumph and Harleys) running nitromethane go over 200, ,,

Naturally Aspirated Naked (N/A'ked),,, i can only think of four, Fred Vance (204), Jamie Williams (209), then maybe Brenda-Sue Carver and Billy or Ryan (help me out here Greg), , given the fact that we had those meets cancelled, and we are all still relativly new to this sport, i dont think that we are that far behind the States, "bring it on" ,,,

On the way home i was thinking of how hard the air seemed compared to Bonneville, so i emailed Jim to ask him if i was imagening it or what, he answered back that it is noticably thicker at Gairdner, ,,

[Greg Watters]

I remember Brenda-Sue getting her red hat last WOS but i'm not sure which of that lot has the naked record

Quite surprised me just how much the air density could be felt in 2010 , all the more congratulations to those over 230 here ,Noonan blasting away on slushy salt and i recon Brett would be 250 or so there

[hawkwind]

Ok blokes I did some research and found there is a profound difference in trying for records here and at Bonneville ...as the seat of the pants feeling shows as well as the across the board speeds indicate ... we are quite likely nowhere behind the performance of the Yanks as speed results indicate.

The problem lies in our relative density altitudes ...which basically means the air is more dense at lake G ...denser air makes for more horsepower and more drag and its this drag penality that I am interested in looking at.

Firstly I collected some data about the weather and altitude from BV and LG.... I used wendover weather data and nonning weather data ....

Wendover .... August avg temps = 33 C RH = 39% and altitude is 4219 feet.
Lake G .......feburary avg temps = 33 C RH = 57% and altitude is 396 feet.
From this data the following was calculated
Bonneville .... density altitude = 7746 ft..........air density = 0.0594 lbs per cubic foot
Lake G ........ density altitude = 3200 ft..........Air density = 0.0696 lbs per cubic foot

Next using a generic partially streamlined MC velocity = 200 mph....... Cd = 0.5 ....... frontal area = 16.15 sq ft and the different Rho for BV and LG the following drag forces were obtained.

Bonneville 641.2 lb /f or 290.9 Kg /f Lake G 739.5 lb/f or 335.4 kg/f......so yes we are having to push against a much greater force to do the same speeds ...and as a side note because we are also having to use more RWHP to do it we will have greater problems with traction so we have to deal with a double whammy just to compete with their speeds......... So IMHO to compair speeds it is like apples and oranges our speeds will need to be adjusted to allow for the difference in air density .

Cheers
Gary

[Stayt`ie]

Gary, without going into detail your calculations are pretty close to what i had worked out before this years event, that is, approx 13% difference, , i have crossed referenced my data from Bonneville with that of this year, yup 13% depending on the day,, i will be now useing it as a "rule of thumb", ,, however thats not to say ya gunna go 13% faster, ,,,

[Jim Ashcroft]

Jimbo ran 192mph with no helmet, no leathers, and the side-stand down. Beat that!

[Stayt`ie]

good aero them naked 14"s, the winds not even ruffling the hair on his head, ,,,

[hawkwind]

Just out of interest I keep being told you need at least 300 RWHP to go 200 naked at Bonneville ? seems a lot can anyone confirm this ....Ronnie what sort of power were you producing to do 198 here ?

Cheers Gary

[Stayt`ie]

my bikes making 220 at the wheel, (ProCycle Dyno Brisbane, late January this year),

[BONES]

Hey Hawk
I'm up for this 200 naked caper.
Going to build the 'universal chassis' mk 3 which won't be so universal but will have a bussa in it.
Have you got a damaged or useable head for a bussa I can borrow?
How much hp is needed with 2/3 the frontal areato go 200?
cheers Bones

[Greg Watters]

common thought is 200hp to go 200mph at Bonneville with bodywork ,
have to work out the hp differential to Gary, only needs about 180 to do it here
bigger horses ???

[hawkwind]

Ok here are some thoughts and paper napkin calcs.
Quite a few years back there was a wind tunnel shoot out between the ZX12 and the Busa so some real world figures were generated a stock busa had a Cd of 0.56..... a frontal area of 6.01 sq ft and weighed 478 lbs .......... further research came up with no real world Cd numbers for a naked bike ....... but some research back in the 50's by tony foale and vic willoby (sp) found a 25 -30% greater Cd between a faired bike and a naked bike , also I found that a faired bike has on average 10% greater frontal area compaired to a naked bike ....... so using the busa numbers and adding 25/30% more for CD and 10% less for frontal area I came up with the following figures

Ronnie said his kawa had a RWHP of 220 so I pluged in the above numbers and came up with ..... Cd of 0.725 211.24 HP to do 198 mph and 219.55 HP for Cd of 0.754 which seems to be in the ball park.

So with 217.63 HP for the lower Cd and 222.73 HP for the higher Cd for 200 mph .... either im way off or the Yanks are with there 300RWHP for 200mph naked.
As im chasing Noonans new A-BF / 1000 record at 227 mph I need around 350 HP to do that... the new rebuild should do that with ease but putting it to the salt now thats another story.

cheers Gary

[Stayt`ie]

Bones, have been thinking 'bout ya 2/3 frontal, mate, what ya lose up front ya gunna have to put in length, lose frontal area, gain more drag ,, then again, being an "A" bike, a very well thought out tail section hasta help heaps,

[JonB]

Theres a fair bit you can do with the tail of an M bike as well
Closing the hole is at leat as important as opening the hole IMHO.

Jon