Author Topic: By Jupiter  (Read 40287 times)

Online Vixen

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Re: By Jupiter
« Reply #255 on: December 04, 2018, 08:21:58 PM »
Hi Craig,

It's a full size engine, in miniature.     It should be powerful enough to power a hang glider or microlight.

I have also got good documentation, some blueprints from 1929 and there are a small number of surviving Jupiter engines in UK museums. So, I have no excuse.

Mike
« Last Edit: December 04, 2018, 08:26:37 PM by Vixen »
It is the journey that matters, not the destination

Online crueby

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Re: By Jupiter
« Reply #256 on: December 04, 2018, 09:09:08 PM »
Simply stunning work!
 :popcorn: :popcorn: :popcorn:

Online Vixen

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Re: By Jupiter
« Reply #257 on: December 04, 2018, 09:50:15 PM »
My dear friend Dan, in France, deserves most, if not all, of the credit for this beautiful engine. I am only completing what he started, twenty years ago. I struggle to maintain his high standards

Mike
« Last Edit: December 04, 2018, 10:05:08 PM by Vixen »
It is the journey that matters, not the destination

Offline Art K

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Re: By Jupiter
« Reply #258 on: December 05, 2018, 03:22:21 AM »
Mike,
From looking at this work of art as it progresses, and I have to disagree.
Quote
I struggle to maintain his high standards
Dan may have started this project but he passed it off to be finished by someone capable of a very high standard of work, you. Keep up the good work.  :headscratch: Are you sure you want to throw the Jupiter in a microlight?
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Online Vixen

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Re: By Jupiter
« Reply #259 on: December 05, 2018, 10:04:42 AM »
:headscratch: Are you sure you want to throw the Jupiter in a microlight?
Art

Art,

Ha ha, Well it wont be happening any time soon. It would need all sorts of CAA inspections, tests, certifications etc, so I will stick with the trusty old Rotax for now.

Mike  :noidea:
« Last Edit: December 05, 2018, 10:17:54 AM by Vixen »
It is the journey that matters, not the destination

Offline fumopuc

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Re: By Jupiter
« Reply #260 on: December 05, 2018, 10:07:53 AM »
Hi Mike,
some holidays and some time to study your postings
The job you have done so far is brilliant and so far away of my skills.
I will enjoy all future steps.
Kind Regards
Achim

Offline Steamer5

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Re: By Jupiter
« Reply #261 on: December 06, 2018, 05:52:38 AM »
Mike,
 Just caught up....just WOW! Canít wait for the video

Cheers Kerrin
Get excited and make something!

Online Vixen

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Re: By Jupiter
« Reply #262 on: December 11, 2018, 04:01:56 PM »
Hi, thanks for calling by and saying hello.

This week it was back to the Induction Spiral and Induction Cover.

You may remember that the Induction Spiral is a unique feature of the un-supercharged Bristol Jupiter engines. It's purpose was to ensure an even fuel/ air mixture was delivered to each cylinder from the three barrel carburetor.  The spiral flow helped to prevent fuel droplets from forming and spoiling the fuel / air ratio. The flow from each inlet port was directed in a spiral motion to three of the nine cylinders.

The real Induction Spirol was an intricate aluminium casting. After several unsuccessful attempts, I had the Spiral 3D printed in a nylon material.




The raw print needed quite a lot of hand finishing with wet-n-dry abrasive paper to smooth the surface and make it fit the engine casings.




Then I turned my attention to adding the finishing touches to the outside of the Induction Spiral Cover. I made these tiny fuel priming bosses on the CNC mill and bonded them to the rear cover. The bolts, which act as fuel jets, also secure the brass banjos of the priming system pipework to the bosses on the rear cover.






Here you can see the rear cover in place on the back of the engine. One small job completed, a million more still to be done.

Damn, just dropped the rear cover and bent one of the studs. It should bend straight, with luck.




                                     "Like a circle in a spiral, like a wheel within a wheel,
                                    Never ending or beginning, like an ever spinning reel.
                                                       Let the images unwind,
                                   Like the spirals that you find, in the Jupiter in your Mind"

Mike
« Last Edit: December 15, 2018, 01:50:32 PM by Vixen »
It is the journey that matters, not the destination

Offline cnr6400

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Re: By Jupiter
« Reply #263 on: December 11, 2018, 10:40:56 PM »
Great work Mike, sorry to hear about the bent stud. Hope you have a few spares.

Was the idea of the spiral to get the intake charge rotating fast, like a cyclone dust extractor, to get the heaviest particles to fly outward toward the walls?

If so, where did the drops of fuel end up? I just have a picture in my head of all the drops coalescing into a river of liquid fuel dripping down into the lowest part of the manifold (particularly at idle)  and putting out the fire in the bottom cylinders! I probably don't have the whole concept right, the designers probably sorted it out some clever way.

Online Vixen

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Re: By Jupiter
« Reply #264 on: December 11, 2018, 11:32:29 PM »
I understand the idea of the spiral was to keep the fuel / air fully mixed and moving at a steady pace. The handbook says they introduced the spiral to prevent stagnant air pockets which could rain fuel droplets. Before they introduced the spiral, the bottom cylinders always ran richer than the upper ones. I don't believe the airflow was fast enough for the cyclone dust extractor effect.

By the 1930's the aircraft were then flying high enough to warrant the extra expense and complexity of a supercharger. The centrifugal blower acted like a huge food blender and solved the fuel droplet problem completely.

Mike
« Last Edit: December 12, 2018, 03:29:41 PM by Vixen »
It is the journey that matters, not the destination

Online Vixen

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Re: By Jupiter
« Reply #265 on: December 15, 2018, 10:02:34 PM »
As I have said before, the purpose of the Induction Spiral was ensure even distribution of the fuel air mixture to each of the nine cylinders.

The individual carburetor chokes each fed three cylinders distributed 120 degrees apart. This made sure the product of each carb was evenly represented around the nine cylinders. So that if one carb was supplying a mixture richer or leaner than the others, the discrepancy would be evenly distributed around the engine, preserving, at least, the balance if not fuel efficiency.

Before delivery to the customer, each Bristol Jupiter was run up on the outdoor test stands and everything carefully adjusted. The three carburettor barrels were individually adjusted to achieve the correct running mixture at tickover, cruise power and for maximum take-off power and all points in between. This was done in the test stands, late at night, with open exhausts and full power, for as many hours as needed. The colour and intensity of the exhaust flame gave the test engineers a clear indication of the mixture strength and evenness of distribution.



                                                                      "By Jupiter, what a racket"

The local residents must have been impressed with the thoroughness of the Bristol engineers working late into the night.

Mike
It is the journey that matters, not the destination

Offline Ye-Ole Steam Dude

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Re: By Jupiter
« Reply #266 on: December 15, 2018, 10:10:30 PM »
Hello Mike,

That is a neat photo, I can almost hear the roar.

Have a great day,
Thomas

Online crueby

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Re: By Jupiter
« Reply #267 on: December 15, 2018, 10:32:28 PM »
Fantastic photo!

Offline Art K

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Re: By Jupiter
« Reply #268 on: December 15, 2018, 11:06:57 PM »
Mike,
Looks like a lot of work to be sure of proper running. Cool photo. Reminds me of the blip of info about the Brough Superior. Each bike was taken out to the sand flats in Wales and run up to 110 mph guaranteed.
Art
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Online steamer

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Re: By Jupiter
« Reply #269 on: December 16, 2018, 12:06:20 AM »
"Listen to the sounds of my people!!!"  :lolb:   I suspect a couple of years in,....it was getting pretty old.

Dave
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Damned ijjit!