Ecurie Martini
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Re:Hear Yea! Hear Yea! Proxy Round 1 Announcement - 2008/07/18 18:13
Running sub-title "Excuses, excuses"
(Warning - long post)
By Wednesday evening, it had become abundantly clear that the only way the P99 was going to make it for opening race of the series would involve the purchase or an airline ticket and hand-carrying of the car to the venue. While I am willing to go to some considerable lengths in the pursuit of my passion, this seemed a bit much but, as the prototype did not contest all of the races in its first season, we hope that we shall be allowed to join the series in progress.
As to the reasons - as the final weeks unrolled, the project began to remind me of one of the more delightful bits of comic writing that I remembered from some years back - so - with the reader's kind indulgence:
THE BRICKLAYER'S STORY
by
Gerard Hoffnung
(from his Oxford Union speech)
I've got this thing here that I must read to you.
Now, this is a very tragic thing... I shouldn't, really, read it out.
A striking lesson in keeping the upper lip stiff is given in a recent number of the weekly bulletin of 'The Federation of Civil Engineering Contractors' that prints the following letter from a bricklayer in Golders Green to the firm for whom he works.
Respected sir,
When I got to the top of the building, I found that the hurricane had knocked down some bricks off the top. So I rigged up a beam, with a pulley, at the top of the building and hoisted up a couple of barrels of bricks.
When I had fixed the building, there was a lot of bricks left over.
I hoisted the barrel back up again and secured the line at the bottom and then went up and filled the barrel with the extra bricks.
Then, I went to the bottom and cast off the rope.
Unfortunately, the barrel of bricks was heavier than I was and before I knew what was happening, the barrel started down, jerking me off the ground.
I decided to hang on!
Halfway up, I met the barrel coming down... and received a severe blow on the shoulder. I then continued to the top, banging my head against the beam and getting my fingers jammed in the pulley!
When the barrel hit the ground, it burst it's bottom... allowing all the bricks to spill out. I was now heavier than the barrel and so started down again at high speed!
Halfway down... I met the barrel coming up and received severe injury to my shins!
When I hit the ground..: l landed on the bricks, getting several painful cuts from the sharp edges!
At this point... I must have lost my presence of mind... because I let go of the line!
The barrel then came down... giving me a very heavy blow and putting me in hospital!
I respectfully request 'sick leave'.
As I started to collect plans and photos for this model, I noticed that the P99 carried two fuel tanks, one in the tail and a second alongside the driver on the left hand side of the car. Having already decided to follow the front-engined arrangement of the prototype, i further resolved to run the drive shaft through this same area in order to avoid a rotating bit transecting the driver's abdomen. Obviously, this would entail some gearing but I felt that the high efficiency of spur gears would offer no more drag that some form of flex coupling which i can never get perfectly aligned - and this is the reason for for the reversed rear bracket:
Here is how it worked out:
![]()
/gallery_99_807_37373.jpg target="_blank">http://www.slotforum.com/forums/uploads/1216070554
/gallery_99_807_37373.jpg
http://www.slotforum.com/forums/uploads/1216070554/gallery_99_807_28982.jpg
http://www.slotforum.com/forums/uploads/1216070554/gallery_99_807_5544.jpg
As you can see, there are a total of 6 gears - 5 pinions and a crown gear - more on this later.
The front is conventional with a modified TSRF guide:
http://www.slotforum.com/forums/uploads/1216070554/gallery_99_807_2750.jpg
Another view showing the resulting offset:
http://www.slotforum.com/forums/uploads/1216070554/gallery_99_807_20659.jpg
And the "rattle pan" to which the body was (and will be) attached.
http://www.slotforum.com/forums/uploads/1216070554/gallery_99_807_29356.jpg
Now, I consider myself to be a fair hand at soldering but, nonetheless, the close proximity of the suspension bits meant that more than a few of the joints had to be redone several times over - and then came the gearing. The dreaded "spun pinion" is generally easily avoided by soldering the gear in question to the motor shaft. When, however, there are five of them, involving both (2) 1.5>2 mm sleeved shafts and (2) 2 mm drill blank shafts (drill blanks are solder unfriendly) the opportunities for disconnection are greatly increased!
After several days of testing involving a number of instances of hearing the warning high speed whine (whinge?) of a suddenly unloaded motor, I finally managed to get everything well fixed (I hope) Of course, the drive train need a final test so I held the car in place, applied power and firmly pressed the rear wheels to the track - blowing the crown gear!
Having a functional chassis at last, I assembled the waiting body and began final testing. Now, if you look at a photo or plan of the P99, you will note that the front suspension requires really large cut-outs on either side of the body, leaving only a narrow "wasp-waist" of body work connecting the motor cover to the nose. Without detailing a painful experience, i will leave it to the reader to imagine the results of a high-speed front first encounter with a track boundary.
Repairs, including a steel wire in epoxy reinforcement are complete and the paint is nearly dry enough to apply the decals (again)
I can report one success - the gearing worked out as planned from an efficiency perspective. The bare motor will begin to turn at about 0.9 volts and draws 0.150 amps at 2.5 volts. As installed, with all of the gearing, the motor will turn over at 1.2 volts and draws 0.170 amps at the same 2.5 volts.
Barring a barrel falling on my head, I hope to ship next week
Yr Fthfl Svt
EM
Post edited by: Ecurie Martini, at: 2008/07/18 18:17
Post edited by: Ecurie Martini, at: 2008/07/18 18:21
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.Any way I'll bring the thumbscrews for a start 
