Author Topic: By Jupiter  (Read 75383 times)

Offline Jasonb

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Re: By Jupiter
« Reply #315 on: May 18, 2019, 04:14:19 PM »
Looks good.

Just for the record there is NO lead in EN1A (230M07), it is just a free cutting mild steel and usually colour coded green.

You can also get EN1A Pb (230Mo7pb) which is the leaded form and that is even nicer to cut. but can't be welded as the lead boils this is colour coded magenta

J

PS that reminds me to send off my entry form.

Offline Vixen

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Re: By Jupiter
« Reply #316 on: May 18, 2019, 04:45:22 PM »
Hello Jason,

Thanks for the correction about lead content.
'
For the record, mine was colour coded red rust with 'Sharpie' pen markings. The markings did include the word 'green' However, the colour codes can vary between suppliers

Guildford are calling for our entry forms. Are you planning to be there on both days? I will have a full table available for your use.

Mike
« Last Edit: May 18, 2019, 04:52:48 PM by Vixen »
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Online Jo

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Re: By Jupiter
« Reply #317 on: May 18, 2019, 04:51:20 PM »
Most of my free cutting mild steel has a protective brown coating  ;)


For the record, mine was colour coded red rust with 'Sharpie' pen markings. The colour codes can vary between suppliers

Muddled Engineer is known to use Sharpie colour coding, especially after he has been raiding my Sharpie pen store  ::)

I am making a list of engines to bring to Guildford Mike I am up to 6 so far  :thinking:

Jo
Enjoyment is more important than achievement.

Offline Vixen

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Re: By Jupiter
« Reply #318 on: May 18, 2019, 04:56:57 PM »
Jo,

The more engines you bring, the merrier we will be.  :ThumbsUp: :ThumbsUp:

I will put a table aside for you. If you don't have an entry form, just e-mail Bryan Finch with your list.

Mike
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Online Jo

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Re: By Jupiter
« Reply #319 on: May 18, 2019, 05:11:37 PM »
The more engines you bring, the merrier we will be.  :ThumbsUp: :ThumbsUp:

 :headscratch: Normally it is the more sticky whatsits I bring  ::)

What ever happens don't let Eric near any beer  :hellno:

Jo
Enjoyment is more important than achievement.

Offline Jasonb

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Re: By Jupiter
« Reply #320 on: May 18, 2019, 07:32:12 PM »
Hello Jason,


Guildford are calling for our entry forms. Are you planning to be there on both days? I will have a full table available for your use.

Mike

Just Saturday.

Offline Vixen

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Re: By Jupiter
« Reply #321 on: May 18, 2019, 08:00:21 PM »
Jason,

Thanks for your support on Saturday.

Any one else fancy a day out in the open, displaying their engines on the weekend of 6/7 July?

Let us hope the weather is dry and lots of visitors turn up

Mike
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Offline Art K

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Re: By Jupiter
« Reply #322 on: May 19, 2019, 03:09:08 AM »
Mike,
I'd love to join you guys at the show but its a ways out of my stomping grounds. Have a great time and take lots of photos for those of us who are out of range.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Vixen

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Re: By Jupiter
« Reply #323 on: May 28, 2019, 01:14:27 PM »
Time for another Jupiter fix for all you petrolheads.

In the previous update from 'Vixen's Den' I got as far as cutting the tapered splines into the roughed out propeller hub. When I was happy with the fit of the hub taper onto the propeller shaft's tapered splines, I began the finishing processes. First opp, the roughted out hub had a visit to the Chipmaster lathe, where the roughed hub was tuned to the finished profile and diameter. Next, the internal 40 TPI thread for the extracter ring and the 40 TPI thread for the front drive disk' locking ring were cut on the lathe.

Then, the embryo hub was transferred to the 4th axis rotary unit to enable the twelve splines for the front drive disk to be milled. Note how the milled splines cut through the locking ring threads. You will see this better on a later photo. The hub was then returned to the lathe to have the rear of the hub machined to the correct profile. The rear drive plate is now only 2.5 mm thick.

That prominent #14 plate signifies that this machine was once the property of Her Majesty's Prison Service at Parkhurst Prison on the Isle of Wight. Home to some very 'tough nuts', some very naughty boys.





With the main part of the propeller hub nearly complete, I turned my attention to the front drive disk. First off, I cut another thin slice off the 4.5 " diameter EN1A bar stock. It took a while to cut through, so I had to be patient. Both faces were cleaned up in the lathe before a start was made on the 12 tooth internal spline.





After facing the blank disk, the first task was to bore the central hole to the bottom diameter of the propeller hub splines. I decided to use a similar approach, as before, and used a 3.0 mm keyway broach to form the 12 internal splines, so another indexing plate and a broach guide were made to match this set of splines. The borrowed arbour press was once again used to push the keyway broach through the disk. Again shims of different thicknesses (10 thou steps) were used to achieve the required depth of spline.







Here we can see the internal splines and the finished propeller hub. I was very pleased with the fit of the two parts.







The front drive disk was returned to the lathe so that both faces of the drive disk could be turned to the correct profile. The finished drive disk is only 2.5 mm thick, so I was grateful of the extra material around the outside. It gave something to get hold of in the in the lathe chuck.





Next, the disk was transferred to the mill for the eight bolt holes and all the lightening holes to be machined.The final operation was to make a profile cut around the outside diameter of the drive disk releasing it form what remains of the 4.5 inch diameter stock.





Here is a trial fit of the front drive disk to the propeller hub.





The matching eight bolt holes and lightening holes were machined in the rear plate to line up with the corresponding holes in the front drive disk.





The complete propeller hub assembled with the eight 2 BA clamping bolts.





Finally the completed propeller hub mounted of the propeller shaft ahead of the 2:1 reduction gearbox. More shiny metal.





Other than a few small detail parts, such as the locking ring and extracter ring,  that's another part completed.

I am already planning ahead and obtaining the timber from which I will carve the huge two blade propeller. I am not too familiar with the 'brown stuff' so there will be lots to learn about the laminating and profile carving. Fortunately the weather is warmer so most of the wood chips and saw-dust can be produced outdoors, rather than in the machine shop.

Stay tuned

Mike



It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Offline Admiral_dk

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Re: By Jupiter
« Reply #324 on: May 28, 2019, 04:59:44 PM »
Simply amazing Mike  :praise2:

While scale wise correct - please promise that no one is standing in front of the prop the first few times it runs …
Why - well it scares me that the material is only 2.5mm …. it might be more than enough, but …. I expect it to quite powerful.

I haven't made any such thing as a prop and I can't remember the specific period, but is it a plywood prop ?
I saw a nice old video on YouTube, where NASA (or it's previous incarnation) showing how to make the turbine fan for a windtunnel from plywood - including the form tools for presseng during gluing - maybe inspiration ?

Offline crueby

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Re: By Jupiter
« Reply #325 on: May 28, 2019, 05:49:49 PM »
Wonderful job on those splines!
 :popcorn: :popcorn: :popcorn:

Offline Craig DeShong

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Re: By Jupiter
« Reply #326 on: May 29, 2019, 11:02:39 PM »
Superb as usual Mike.
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Vixen

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Re: By Jupiter
« Reply #327 on: May 30, 2019, 10:31:13 AM »
Hello Per, Chris and Craig,

Thanks for calling in, you are always most welcome.

During the 1920's and early 30's. the Bristol Jupiter was a very important power plant in British and European aviation. At one time the Jupiter powered almost 70% of all the European aircraft built during this period. Bristols built thousands for both military and civil aviation customers, and many more were produced under licence by 12 other engine manufacturers, all over the world. Sadly only a small handful of these magnificent engines have survived, the rest have just disappeared. There are no airworthy, flying examples left today. I am building my 1/3 replica as accurately as possible to try and redress the balance.

Mike
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Online Roger B

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Re: By Jupiter
« Reply #328 on: May 31, 2019, 07:27:11 AM »
Excellent progress  :praise2:  :praise2:  :wine1: Good luck with the brown stuff  ::)
Best regards

Roger

Offline Vixen

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Re: By Jupiter
« Reply #329 on: May 31, 2019, 03:44:15 PM »
Throughout the early years of aviation, including the 1920's and 30's, many propellers were produced from Honduras Mahogany, a species of wood well known for its stability and strength, and at the time readily available. Today there is a total ban on importing Honduras Mahogany into the UK – it’s now an endangered rainforest wood. Fortunately, an excellent alternative timber, West African Sapele Mahogany is available.

The manufacturers of propellers for full size vintage aircraft still endeavour to produce true reproductions of those early propellers from the correct wood species. They have had to become quite cunning and source legal supplies of Honduras Mahogany wood from alternative places. It turns out that in Victorian times, many churches had their pews made out of big slabs of our now endangered mahogany – which they now upcycling into propellers!

My Jupiter propeller saga begins with the delivery of the raw material; eight pieces of West African Sapele Mahogany in various thicknesses. Each board is quarter sawn, planed to thickness and sanded flat to the thicknesses requires to laminate the propeller blank. I have 5 mm and 11 mm boards available.





A British Company, Hercules Propellers Ltd, specialise in reproduction of vintage propellers using the latest CNC router manufacturing techniques. They offered to build a special propeller for my Jupiter, but at a price I could not afford. They must have been very sympathetic to my situation; instead they provided a great deal of technical assistance and the original manufacturing drawings of suitable propellers which could be scaled to the model Jupiter size.

I need to consider only the ground running situation, where an excess of thrust could be a problem; how do you stop the test bench from flying away? After a lot of discussion, we decided it would be best to create a propeller with relatively fine pitch (lower static thrust) much finer than would have been used on a full size engine. A suitable propeller design is shown below. You can see the lamination details and the blade cross sections at different stations along the blades. The table provides the numeric values required to accurately reproduce the sections. My Jupiter propeller will be 40" diameter x 28" pitch. A huge propeller for a model engine, but then the Jupiter model is also big at 1/3 scale



So far, so good.  Another journey into the unknown has begun

Stay tuned

Mike



« Last Edit: May 31, 2019, 05:56:45 PM by Vixen »
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

 

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