Author Topic: By Jupiter  (Read 40233 times)

Offline Admiral_dk

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Re: By Jupiter
« Reply #240 on: November 06, 2018, 10:21:42 PM »
Quote
No single point cutters were harmed during the making of these parts.
    :ROFL:  thanks Mike.

Nice progress (as usual)  :cheers:

Offline Art K

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Re: By Jupiter
« Reply #241 on: November 07, 2018, 02:59:54 AM »
Mike,
The multi point cutters probably run out a bit so there is probably a high point as it spins around.
Art
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Offline Craig DeShong

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Re: By Jupiter
« Reply #242 on: November 13, 2018, 01:14:36 AM »
Anti climatic outcomes are usually welcomed in the shop...just sayin...

 :ThumbsUp:

Still following Mike, this build continues to amaze.
Craig

Online Vixen

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Re: By Jupiter
« Reply #243 on: November 13, 2018, 12:36:03 PM »
The magnetos are nearing completion. In this instalment from Vixen's Den, I will concentrate on ignition trigger circuits. The original BTH magnetos would have had cam operated ignition points. Ignition contact points always demanded constant maintenance and were always potentially unreliable. This unreliability was not something I wanted to copy into 1/3 scale magnetos so I made an early decision to use a magnetic Hall device, rather than contact points as the ignition trigger for my model magnetos. This was a conscious decision and one of the few places where I deviated from the original BTH magneto design and blueprints.

The first photo of the assembly sequence shows the magneto's input coupling. The magneto is surrounded by the components which make up the ignition trigger circuit and the nine cylinder distributor.



The next shows the 63t/28t gears correctly installed inside the magneto's gear housing. They mesh and spin beautifully with little or no backlash.



Here I have added the distributor's rotor arm and the timing plate for the ignition trigger circuit. You can see the single 3mm diameter rear earth magnet bonded into the vertical boss of the timing plate. The timing plate can be moved through about 20 degrees to advance or retard the ignition timing manually. Again this feature is true to the original design, automatic advance / retard had not yet been invented in 1929.



This is the magnetic field chopper blade in position on the input shaft . The field chopper has four blades, each of which will interrupt the magnetic field as seen by the Hall effect pick up device. The position of the field chopper on the input shaft can be set via a single grub screw. The precise triggering position is indicated by the  LED  light on the TIM-6 ignition module. You can see another four blade field chopper more clearly, on the table below the magneto.



The Hall effect pickup sensor is bonded in place, inside the contact breaker's domed cover. It rotates together with the magnet on the timing pate, as the advance/ retard position is adjusted. The contact breaker cover in the photo has been modified for test purposes, the open end allows me see the position and clearances of everything inside.



The final photo of this series shows the full assembled magneto. In the foreground from left to right are 1) a distributor rotor arm, 2) a four blade magnetic field chopper, 3) an unmachined field chopper which can be cut to give different 'dwell' times, 4) a four magnet rotor in case the field chopper blades did not work and 5) the Hall sensor bonded into the test contact breaker cover.



I am happy to report that the four blade field chopper appears to work perfectly and I plan to proceed with this design. In the event that the field chopper idea does not quite work out as expected, when I run the engine, I always have the more conventional four magnet rotor as a backup.

To complete the magnetos, I still have to add the brass contacts to the rotor arm and distributor cap, and off course I need to add the ignition lead harness. I will delay the ignition lead harness for as long as possible as they will get in the way during the rest of the build.



Stay tuned

Mike


« Last Edit: November 13, 2018, 04:14:43 PM by Vixen »
It is the journey that matters, not the destination

Online Vixen

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Re: By Jupiter
« Reply #244 on: December 03, 2018, 11:43:13 AM »
Some more Jupiter progress to report from Vixen's den.

Here is the rear cover, which acts as the accessories drive, I've got it mounted on an angle plate. The two magneto mounting flanges needed some extra machining to clear a couple of interference points.

The rear cover was clamped to a small angle plate, which was set over at an angle of 32 degrees. I used a digital spirit level to carefully set each magneto flange perfectly square and parallel with the mill bed, in both x an y axes. I also needed to rotate the set-up to align two of the existing bolt holes parallel to the x axis. After that, it was just a case of tracing the magneto flange outline with a 6mm end mill in small Z axis increments, until all the points of interference disappeared.




Here the two magnetos are offered up to the rear cover to check the fit.





The rear cover complete with the two magnetos in place on the rear of the mighty Jupiter. 

The rear of the engine is starting to look busy. The cast inlet manifold is at the bottom. The scavenge and pressure oil pumps are in the centre. The two magnetos angled outwards. At the top centre is the mounting flange for the Hand Turning Gear which is used to start the engine with a cranking handle through an enormous gear reduction.




It really is getting to look busy as more parts are made and added.




These are the bevel gears which drive the two magnetos. The centre bevel gear is driven by the crankshaft, the gears have 36:32 teeth with a 32 degree angle.  The two output bevels drive the magneto input shafts at 1.125 times the crankshaft speed.



There's more to follow, so stay tuned

« Last Edit: December 03, 2018, 04:47:40 PM by Vixen »
It is the journey that matters, not the destination

Online steamer

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Re: By Jupiter
« Reply #245 on: December 03, 2018, 12:04:48 PM »
Sweeeet!


Coming along nicely Mike!

Dave
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Offline Ye-Ole Steam Dude

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Re: By Jupiter
« Reply #246 on: December 03, 2018, 01:43:24 PM »
Hello Mike,

WOW!

Have a great day,
Thomas

Offline Kim

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Re: By Jupiter
« Reply #247 on: December 03, 2018, 02:54:51 PM »
I'll say!  Wow!

That's really looking impressive, Mike!
Kim

Offline zeeprogrammer

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Re: By Jupiter
« Reply #248 on: December 03, 2018, 03:17:47 PM »
There's more to follow, so stay tuned

 :ThumbsUp: :popcorn:

It looks awesome!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline Roger B

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Re: By Jupiter
« Reply #249 on: December 03, 2018, 03:20:50 PM »
Excellent  :praise2:  :praise2: The complete engine looks magnificent  :ThumbsUp:  :ThumbsUp:
Best regards

Roger

Offline 10KPete

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Re: By Jupiter
« Reply #250 on: December 03, 2018, 06:00:20 PM »
Wow, that's a beautiful engine!!

 :popcorn:

Pete
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Offline crueby

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Re: By Jupiter
« Reply #251 on: December 03, 2018, 09:39:15 PM »
Wow, that's a beautiful engine!!

 :popcorn:

Pete
Triple that!   :popcorn: :popcorn: :popcorn:

Online Vixen

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Re: By Jupiter
« Reply #252 on: December 04, 2018, 09:24:19 AM »
Thank you all for dropping in and saying hello.

There seems to be an endless amount of small parts required for a big radial engine. For example; the overhead valve rocker arms are located by two control rods. The idea is to control the valve/ rocker clearance as the cylinder expands when running. A bit of an overkill, but true to the design of the original engine.

Each rocker assembly has 6 pivot pins and each floating pivot pin is retained by a pair of bolts. That requires a total of 108 special, short 8 BA bolts to be made up and fitted. A lot of work and you can hardly notice the difference



That's one more item crossed off the list. I'm getting there.....slowly   :help:





« Last Edit: December 04, 2018, 10:12:51 PM by Vixen »
It is the journey that matters, not the destination

Offline Admiral_dk

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Re: By Jupiter
« Reply #253 on: December 04, 2018, 11:33:07 AM »
And we usually think that an engine is more or less made when you have finished the case, crank, conrod(s), piston(s), cylinder(s), valves, camshaft(s) (if any) and a carburator ….. but this build really show how much more goes into the full size ones and models in big size  :o

Fantastic progress Mike.

Offline Craig DeShong

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Re: By Jupiter
« Reply #254 on: December 04, 2018, 06:49:52 PM »
The detail on this model is so extraordinary that it's hard to tell if we're looking at the model or the full size.  Just gorgeous!
Craig