28-05-2018, 12:00 AM
Thank you for your kind comments about the car, reading Dave's remarks about building his 'Cheapskate Special' have struck a cord with me. Similarly to Dave I have used materials collected over the decades. The boat tail is built from 40 year old Silver Spruce which was left over from building a aeroplane and some of the aluminium is also from that project.
These type of projects really do eat up that most precious thing, time, I started building Slippery Anne several years ago, as and when time allowed. I now wonder what I have built, despite having two seats and all the added weight of the extended chassis, the car is actually very light, Erick asked me what spec the engine is, well it has a 1924 crank case containing a 1 1/2" Phoenix crank, it has a compression ratio of 7.5 to 1. The Roots Supercharger has a swept volume of 33.46 cu.in and is driven directly from the engines timing gear, it breaths through a bronze 1 1/2" SU jetted to run on petrol. At present the Supercharger is driven by a 14 tooth gear giving a low level of boost, ultimately this could be dropped to 11 teeth effectively doubling the boost pressure. On the Dyno last week, with a faulty Magneto already causing ragged running, it produced 40 BHP at 4000 rpm, but due to the Mags issues it struggled to rev much beyond 5000 rpm by which point it was backfiring and missing terribly, sounding like a firecracker, but still managing to give over 50 bhp, but with no more revs to give. Once the Magneto is fixed I expect a good 7000+ rpm and between 60 - 70 bhp with a 13 tooth drive gear fitted.
Given the cars 19" wheels and 6" brakes, allied to its slender weight Slippery is starting to look a little intimidating, especially as my 16 year son old is eying it covetously. No brakes, no roll protection, no harness and the MSA requirement that Nomex suits be worn make for a slightly worried Dad.
From a positive perspective, the car has a very low centre of gravity, with the exception of her 2 gallon fuel tank, all the main mass is contained within the wheel base and even a tall drivers shoulder height is only a little above the top of the 19" wheels, so the dynamic qualities of the car should be excellent. I think we will limit her use to hill climbs and sprints.
Magneto issues permitting, I hope to take it off the Dyno and drop the engine into her in the next few days, I will post some pictures then.
Regards, Mark.
These type of projects really do eat up that most precious thing, time, I started building Slippery Anne several years ago, as and when time allowed. I now wonder what I have built, despite having two seats and all the added weight of the extended chassis, the car is actually very light, Erick asked me what spec the engine is, well it has a 1924 crank case containing a 1 1/2" Phoenix crank, it has a compression ratio of 7.5 to 1. The Roots Supercharger has a swept volume of 33.46 cu.in and is driven directly from the engines timing gear, it breaths through a bronze 1 1/2" SU jetted to run on petrol. At present the Supercharger is driven by a 14 tooth gear giving a low level of boost, ultimately this could be dropped to 11 teeth effectively doubling the boost pressure. On the Dyno last week, with a faulty Magneto already causing ragged running, it produced 40 BHP at 4000 rpm, but due to the Mags issues it struggled to rev much beyond 5000 rpm by which point it was backfiring and missing terribly, sounding like a firecracker, but still managing to give over 50 bhp, but with no more revs to give. Once the Magneto is fixed I expect a good 7000+ rpm and between 60 - 70 bhp with a 13 tooth drive gear fitted.
Given the cars 19" wheels and 6" brakes, allied to its slender weight Slippery is starting to look a little intimidating, especially as my 16 year son old is eying it covetously. No brakes, no roll protection, no harness and the MSA requirement that Nomex suits be worn make for a slightly worried Dad.
From a positive perspective, the car has a very low centre of gravity, with the exception of her 2 gallon fuel tank, all the main mass is contained within the wheel base and even a tall drivers shoulder height is only a little above the top of the 19" wheels, so the dynamic qualities of the car should be excellent. I think we will limit her use to hill climbs and sprints.
Magneto issues permitting, I hope to take it off the Dyno and drop the engine into her in the next few days, I will post some pictures then.
Regards, Mark.