Author Topic: Harrison L5 rescue  (Read 132408 times)

Offline Biggles

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Re: Harrison L5 rescue
« Reply #225 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? 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:

Offline Houtenkrullen

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Re: Harrison L5 rescue
« Reply #226 on: January 10, 2016, 06:20:34 AM »


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?

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

Offline Will_D

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Re: Harrison L5 rescue
« Reply #227 on: January 10, 2016, 06:38:18 AM »
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!!
Engineer and Chemist to the NHC.ie
http://www.nationalhomebrewclub.ie/forum/

Offline Biggles

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Re: Harrison L5 rescue
« Reply #228 on: January 10, 2016, 01:52:36 PM »
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:

Offline Jonny

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Re: Harrison L5 rescue
« Reply #229 on: January 10, 2016, 06:41:31 PM »
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.


Offline Biggles

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Re: Harrison L5 rescue
« Reply #230 on: January 11, 2016, 02:35:20 PM »
thanks Jonny, i will lookout for them, i think the fibre gear was just their for the noise, otherwise they would have made them in different sizes to fit the translation gear changes.  :thumbup:

Offline vintageandclassicrepairs

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Re: Harrison L5 rescue
« Reply #231 on: January 17, 2016, 12:42:55 PM »
Hi All,
I just spotted some 14DP gears on Ebay (rusty but cheap???)

http://stores.ebay.co.uk/The-Plane-Iron-Shop?_dmd=2&_nkw=14DP

HTH
John

Offline awemawson

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Re: Harrison L5 rescue
« Reply #232 on: January 17, 2016, 12:57:08 PM »
That ad. is Tim & Digger at G&M Tools in Ashington (West Sussex) - dealt with them for decades !
Andrew Mawson
East Sussex

Offline Biggles

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Re: Harrison L5 rescue
« Reply #233 on: January 18, 2016, 01:29:33 AM »
awemawson, vintageandclassicrepairs, i live between Epsom and Kingston. ref; the gears advertised by G&M. i have had a few for spares but they did not have the specific ones i am after. 40, 63, and 127. These are required for metric threads. I am in the process of stripping the lathe down and repairing it along the lines of mick of this thread. Therefore I will start a new thread when I have got a few days behind me and found out what needs to be done. One thing is for sure; screws and nuts are hacked and need replacing, assuming I can get them off.  :nrocks:

Offline tom osselton

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Re: Harrison L5 rescue
« Reply #234 on: January 18, 2016, 04:10:37 PM »
Maybe message Doubleboost he had the 127 division dividing plate made up.