The Shop > Tools
Harrison L5 rescue
Biggles:
RussellT, Stuart, I have not noticed a shear pin: I seem to recall that the fibre gear was used to dampen the noise from the steel gears. I would think the fibre gear will take the strain if there is a crash? And why make something in alloy if it can be made correctly at the same price? Assuming the manufacturers new their stuff! :zap:
Vintageandclassicrepairs, The radial engines on the Dakota are something to behold and a little daunting if you are a passenger, especially when they start up at night and shoot flames. :bugeye:
Houtenkrullen:
--- Quote from: Biggles on January 09, 2016, 05:52:20 PM ---RussellT, Stuart, I have not noticed a shear pin: I seem to recall that the fibre gear was used to dampen the noise from the steel gears. I would think the fibre gear will take the strain if there is a crash?
--- End quote ---
Biggles,
I know nothing about your lathe, but on my lathe (ai-hembrug dr1ls) there are two fiber gears (in the tumble reverse to be specific) that will protect the rest of the gears. They are known to break, not even needing a real crash to do so. As far as I know there are no shear pins in the gear train of my lathe, and ai hembrug is known for it's thorough and sturdy design.
If there is no shear pin I would assume that your fiber gear has the same function. After all Harisson is not exactly Chinese wishful thinking, is it?
Peter
Will_D:
My first ever flight was on a DC3 from Cardiff to Jersey for hols! Must have been early 60's
Still remember lookinng out at the engine cowling and seeing bits of it flapping!!
Biggles:
Hi Houtenkrullen, I have been looking into the expanded drawings of the Harrison. The drive box seems to be well protected with pins, in addition the main drive is on a friction clutch plate working from the belt. Therefore i assume this will be sufficient for any problems. By the way, i also went through some of John "doubleboost" videos last night. He had one set on cutting gears for the Harrison, where he used larger gears to cut down to size. The most interesting thing to me at this stage, he mentions a formula for calculating the external diameter of a gear wheel knowing the DP and number of teeth. ; diameter = (number of teeth+2)/DP; much easier that using a program! :coffee:
Hi Will_D, yes they do scare people who have never been on one and accustomed to our modern jets. But I assure you they are much sturdier than any modern composite! :thumbup:
Jonny:
Just had a look at an old picky of mine lathe long gone, theres a shear pin approx. 3/16" on both lead screw and counter shaft covered over and slides away towards tailstock when they break. Had to do mine once after putting a cut on, 1ph 240v 1 1/2hp original motor barely grumbled.
No fibre gears all steel throughout, had full set of change wheels as well impossible to acquire.
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