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 Phenomena-Plus

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john bass

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Number of posts : 1727
Age : 88
Localisation : Bensberg, Germany
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PostSubject: Thanks Mick...   Sat May 26, 2012 9:43 pm

Thatīs a good graph Mick but coefficient of air resistance at 0.6 is far too high. According to my Bosch Auto Handbook that is the Drag Coefficient of a station wagon. With a streamlined car -- which has a long tail -- the Drag Factor is 0.25.... I estimated Dick Hunter without fairing as 0.28 -- he was so tucked in and his legs couldnīt stop much air flow.... A planimeter, reading a front-on picture of rider in racing crouch is what is needed to determine the frontal area....

As long as you do not find this boring, Mick -- and I know you know what you are supposed to be looking at -- Iīll carry on with posting my thoughts and ideas I have relative this topic & other technical topics. Otherwise Iīll pack it in and just chat socailly.

As I said before, I do the calculations and drawing of graphs FOR MYSELF -- there is no need for me to go to the bother of posting on here for no real purpose if there readers on here who donīt want it or "...donīt know what it is they are supposed to be looking at..." when it is quite clearly defined. Rolling resistance can be found experimentally and once the frontal area is determined the Air drag can be calculated.

On that Map 1 of TE - TR, I showed several "More realistic TR curves which can be taken as attributable to higher mechanical friction and losses OR the TR on uphill inclines. For Andy Boyle, when I was helping to develope his 250 ABS, I used to note max revs in each gear in practice at meetings and at Brands training sessions so that we could establish the gear ratios for each circuit. For every outing, on the ABS, he got from me a circuit diagram showing the max revs in each gear and roughly where I changed gear... I felt it a duty because of his lending the bike. When we met up after 35 years or so he gave me copies of those curcuit diagrams. Brings back some really soppy nostalgia!

What was the bother with your bike, Mike, at Cadwell?? What happened to Mark Cargill?

Cheers!
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john bass

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PostSubject: So, the next bit...   Sat May 26, 2012 10:06 pm

So, the next bit -- MICK!

Is what happens up to 40 to 45 mph? with a Bantam -- Clutch Slip definitely increases the final drive ratio to the rear wheel...

Splatt!

I felt something on the ether -- maybe I am getting too sensitive!!??

Cheers!
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Derek

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PostSubject: Re: Phenomena-Plus   Sun May 27, 2012 5:37 am

Hi John

I think the penny may have dropped, no need for the smarmy comment mate,

but just to clarify are you saying this graph tells us what gears we should be running or tells us where the best place to change gear are. ?

I usually change gear when the rev counter touches 8800 or I may change early for a specific corner coast in and run out under power, meaning I don't have to try and change while looking at the rev counter and whilst trying to miss those around you and concentrating on getting the corner correctly, or I change where it peaks on the torque graph, besides Rev counters can never keep pace with actual revs, there is a lot of lag especially if the bike excellerates quickly and you have an analogue rev counter,!!!!!!!! one of the reasons why one bike has lights ?

regards Derek.

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mscutt

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PostSubject: Re: Phenomena-Plus   Sun May 27, 2012 11:04 am

Hi Derek

you have to remember that the graph is based on a simulated power curve and is itself a simulation of the performance from a given rpm so the actual numbers produced can be taken with a large pinch of salt.

The graphs were added when JB mentioned he was doing some and show the tractive effort at the rear wheel in each gear compared to the total resistance - air drag and tyre drag. The purpose of this program was to try another way of comparing power curves from a simulator. You can set it up with any set of parameters you like but if you keep them consistent then the acceleration times it gives seem realistic and do what you expect.

The 0.3 sec gearchange time is realistic for a Bantam with no special clever stuff, just a size 9 boot. The time has been measured and is usually between 0.25 and 0.4 secs.

By trying different rpm to change gear you can see on paper what you usually know by feel as to the best time to change gear which is usually different between 1st/2nd to 2nd/top.


Mick


Last edited by mscutt on Sun May 27, 2012 11:26 am; edited 1 time in total
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mscutt

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PostSubject: Re: Phenomena-Plus   Sun May 27, 2012 11:25 am

Hi John

The 0.6 Cd figure was just a value I was playing with but from what I have read, its unlikely a Bantam or other non works racers for that matter will be below 0.3 and a more realistic figure is nearer 0.4 which would perhaps give curves nearer your other resistance curves?

The rolling resistance was calculated with some formulae published in 1973 by a chap called Kevin Cooper who was involved in a record breaking Can-Am bike.

I have no idea how to handle lower speeds when clutch slip is needed which is why I woke up and got interested when you mentioned them!

At Cadwell, my engine had a structural failure - the barrel parted company from the crankcases when a weld broke! Its on the mend now and will be out at Snetterton.

Mark Carkeek had a fall at the Gooseneck as did 13 others on Saturday and several more on Sunday, often on the first lap. No sign of oil at the corner but suspect the poor grip is because the surface is polished by cars drifting through there.

Mick.
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john bass

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PostSubject: Yeah Well...!You are suggesting ...   Sun May 27, 2012 9:25 pm

Right Mick! you are suggesting My Bosch Handbook might be over optimistic -- as I am about Bantamite Air Drag coefficients ...

... and you could be CORRECT... I say that because a Lecturer at the East Essex Tech College -- way back in the late 50sī -- gave 0.3 for fully streamlined where my Bosch source (for a similar shape) says 0,25 and gives optimum streamlining as 0.15 to 0.20 which sort of drags in OPINION on "Optimum Streamlining" and needs more factual data to make a positive conclusion. The Handbook is very good. Each subject has a different (professional) contributor yet I did find an inaccuracy in one case. I wrote in and got a likely explanation -- for the inaccuracy -- from the author, which was quite pleasing....

One thing for sure in Bantam racing, is that having the means of good acceleration is a prime factor in being competitive, at all, and keeping the speed on in the bends is the only way to success...

Re my notions on clutch slip being a torque multiplier. It seems by responses on here that I was a rare case in clutch-slipping so much as I did. Certainly with the 5-speed, 250cc ABS -- and a lot more torque -- I only slipped the clutch at the start.

Mick, if you feel a diagram would help in the clarification Iīll gladly provide such -- or, is there a programme on the net...?

From the aspect of experience I used the technique for most bends when racing Bantam. I guestimate the Icarus-1, Bantam max torque to have been at around 7.5ftlbs at 8,000 rpm (no dyno testing for us...) so approaching bends such as the hairpin of Cadwell club curcuit days and Druids at Brands Iīd be changing down whilst Braking and at the same time de-cluching -- quite a way before the bend -- getting the revs back up to max to drive hard all the way round -- which gave a distinct FEEL of having more torque than when in the clutch- coupled condition.

Enough for now...

CheerS!
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Derek

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PostSubject: Re: Phenomena-Plus   Mon May 28, 2012 5:20 am

JOHN MAKES AN INTERESTING COMMENT ABOUT THE CLUCH - I think we really should try and look at alternative materials, metal in the box is just not the ideal situation, did'nt some one say there was a dry clutch Bantam being built, I will ask my dad what happened to ours, Im sure he still has the castings, getting rid of that heat must be areal problem, unless you have water cooled cases,! i understand some of the guys running all metal clutches and water cooling run watercooled packing rings feed from the inlet side.

This is for sure a lot of enginuity and complication, but is it worth the effort, ???? anyone,

I was also wondering what temperature the cases run at with and without this mod, and what difference it makes, ?? anyone.

Regards Derek
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john bass

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PostSubject: Changing gear too early if...   Mon May 28, 2012 5:44 am

Deleted....


Last edited by john bass on Mon May 28, 2012 6:29 am; edited 1 time in total
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Derek

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PostSubject: Re: Phenomena-Plus   Mon May 28, 2012 5:50 am

Hi Mick only just spotted your reply, "thank you" - on the drag - I had this measured with a lucky opportunity recently, for a Todd fairing with me behind the screen at 0.33 to 0.36 however, with some clever work "cardboard and tape, under the tonsil to creat a relief the air friction factor rcan be reduced considerably, also the the shape of the duct at the lower part of the fairing at the bottom, we made what we thought was ok after these tests, when we tested it, again it was much worse! so we removed it for Cadwell, I am making it again, my fibre glass is not as good as some, also my apparent lack of understand exactly what im doing is possibly another factor, but im enjoying trying.

from the results explaind to me, this area (btm of fairing can be taylored along with the fairing just infornt of the handle bars together this and will also lower considerably the drag factior as much as another 2.5 to 3% drag reduction, aproximatly and roughly explained to me it could make the difference of another 4 to 5 MPH above 90mph. i like this type of explanation, as its realyeasy to understand rather than factors and calculations, that I dont want to understand, but I have to say they do look impressive.!

but racing as I did at cadwell sitting up most of the time, Im sure Micks figures are accurate at 0.6 my helmet and shoulders will make all the difference, above the screen but approx 75mm or 3 icnches above does not seem to make any difference only when you expose the shoulders drag factor seems to really move. (apparently). thing is its so blumin difficult to remember to get your head down as soon as you come out the corner, I seemd too busy looking to avoid someone or trying to miss running into the back of them, I have to say in the heat of racing when all are cornering exiting at the same sppeed this must be easier, but a lot of those Ducati guys seem to have better top speed of exiting the corner however there were a lot slower mid corner,!! I think it was much safer when they were at the front two or three rows in front of us, never seen them in the last race at all.

John there are a number of interlectual items for you, but sent them to you via PM, as Im officially educating you I thought it best you have them via PM.

I dont want to give to much away "to soon". !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

regards Derek
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john bass

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PostSubject: PMs donīt get to me for some reason...   Thu May 31, 2012 4:40 am

Hi DereK! Thanks, but PMs do NOT arrive. Yours and two others (who told me they were sending...) have NOT arrived -- here.

It could be that I recently got myself another Security system since being warned of The Flaming Torch (Olympics this year you know...!!) & Trojan Horse packets that are doing the rounds since March 2012 and have destroyed the memory of many PCs in America & Asia... This new security system probably isnīt capable of recognising all UK identities....

A recent report from the Security stated that I had had several `Trojansī among 21 suspect incoming messages -- in 3 months. Adding that they might only have been for annoyance value -- but one out of the lot could have been a virus ... I wonder if the scare tactic is to get more customers ... but after last yearīs experience I donīt want to risk it....

Another one, just recently was, "... a friend on Facebook wants you to make contact ..." (I think I mentioned this one on here earlier) and when you do try to contact the sender the virus attacks. Sometimes it is so rapid that you donīt get a chance to dou anything about it. Luckily when it happened, to me last year, I switched off my "T-Com..." modem as the picture slewed across the screen -- [it was like snatching at the clutch lever when the Bantam rear wheel locks] -- and I saved about half my files but I had to have the PC at our local Computer Specialists to reprogramme start-up and several other of my file systems....

Maybe I am being too pessimistic about this but once bit -- twice shy. Particularly when it cost about Euro120 (roughly a 100 quid) to have put right....

All the best!
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Derek

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PostSubject: Re: Phenomena-Plus   Thu May 31, 2012 6:11 pm

Hi John I defernatly sent them mate, they went along the lines of this cut and pasted from my PM-

CUT AND PASTED FROM DEREKS pm.
John Im just about to have a dig the undertone is a personal dig at the London Boys and mike powell - to see if I can wind them up before Snetteron, certainly helped and di the trick for our Nick and a few others at Cadwell, they were off their games mate its all phycotherapy or spelt something like that,

so what ever you do dont bite or take the bate - its not intended for you my buddy- its for the bigger fish currently racing - Im just having a bit of fun and digging at Mike to see if I can have the same effect at snetterton". if IAN FALLS ON ON THE SITTING LAPO AGAIN YOU KNOW just not got his mind on the job, I was pleased he was unhurt though, bloody slowed him down a tad!

Im meand did you see what happened the list goes

ROB RACE ONE NOT SURE WHERE HE WAS ! i THAINK HE FORGOT TO SAY THANKS TO THE MARSHALLS IN PRACTICE SO DECIDED A LITTLE DE TOUR IN THE RACE TO SAY THANKS GUYS !

IAN DROPPED IT ON SOME OBVIOUSLY OILEY bULLSHIT IN THE GOOS NECK. (CALLED GOING TOO FAST TOO SOON ON COLD TYRES WHILEST THINKING ABOUT WHAT ON EARTH IS THAT GUY GOING TO WRITE NEXT) LOL

i HEARED Tom forgot to do up the nuts holding the clucth cover on MICKS bike ?

I need to find some words to write about this! this could deveklop into a real pizztake - but I will try so hard to bee good and nice, in Birmingham this is classed as saying ok, when you really take the pizz its classed as being really frindly.

I approched one individual not to be named as I dont want to upset his phycological status - (completly gone) mind condition, my goodness "I was so upset" can you believe he would not talk to me, or shake my hand! he almost broke into tear when I tried to say hellow and tell me so avoid a hand shake, !

Great completley syked him out, Im now not sure I moved forwards as a result of the bike or the mind games Ive been playing on here !

But what ever it is - I need to increas the rate - its certainly sems to be working. "shame but life can be bitch -difficult" when your on the recieing end.

hmm the only person in the London boys really with his head in gear and such a nice yourng man, was riding really well and on it, was that young man Robs son "Michael" - yeh always liked him nice guy.

He's clearly more of an opponent where the head games and stakes are concerned, the rest completley "syked out" "no competition - mino's". !

John you take care now and dont forget, "dont take the bate",

- cut and pasted -

best and kind regards Derek
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john bass

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PostSubject: It is a war ...   Thu May 31, 2012 9:15 pm

It is a war...

...you have started a psycho war Derek and Iīm on the London side. Sort of below St Albans are our lot ....

No matter that Ian is lost up north somewhere -- we include Ian of course -- oh! and Mike Powell because he was never one of your lot anyway*** ...

Now that is firmly established I think the REAL war should begin after the last Cadwell, Sunday evening -- I have appointed myself CinC London Unit (I have made plans to be there!) and have already planned our tactics ... We will let you know, well before the event, the weapons we shall use. Custard pies are the last option -- they cost too much and some London Bantamites might be tempted....

Letīs get back to Phsycho in MC racing. I went with Slick, when he was working for Virginio Ferrari, to Hockenheim. 33 people in the supporting cast of Carl Fogarty & Neil Hodgeson and yet the Ducatis were slower than the Castrol Hondas -- IN PRACTICE. Reporters were here, there and everywhere probing and reporting... even in the teamsī hotel till early hours of race morning grabbing at information and gabbing on about who said what? Slick had made sure that everyone knew that Carl was most upset with being, "...2 seconds off the pace..." and that, "...the Ducatis havenīt settled on the suspension units yet..." . That, althought the Oleo (name forgotten, suspension people from Scandanavia someplace?) Specialists denied the rumour which went round the bars and rooms until after breakfast and continued into the Hockenheim pits ...

Then it came to the 1st WSB race where somehow Slight (Honda) who had led for a number of laps was passed both by Neil and Carl (Ducatis) with Neil leading on the last lap until the left hander in the Motodrome curves. The Ducatis came together & Neil ended up off the track, along the grass but still aboard....

I have also sent several PMs, on here, which I reckon never got to the other end because Iīm sure the intended recipient would never ignore such a message.

*** Mikeīs really from across the border...
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Derek

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PostSubject: Re: Phenomena-Plus   Fri Jun 01, 2012 3:31 am

love it John.
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