How Can I make this in Aluminum or Stainless Steel?

[Jose V]

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

[Don Smeller]

Jose,

This is not complex.  It is doable several different ways.  Lathe cutting, casting, CNC milling.

We can probably 3D print it at 10Bit, then make a sand mold, then pour molten aluminum to make the finished part.  

Rather than exporting to STL format, export it as a STEP file.  The machine shop people will appreciate it. They can’t pick off dimensions from a STL file.  They may have blown you off because it looked like a lot of work to educate the newbie.  The actual machining work is a piece of cake.

Don

On Jul 20, 2017, at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[Jose V]

Thanks Don, after 10bitworks has officially moved and is done setting up I can come by.

[tookys3]

Some concern may be that the walls are very thin compared to the rest of the body.

The internal shape is easy. 

The issue I think the machinest have is that the walls are extremely thin, and their ability to hold it during machining is very limited.

On the outside leave it as much as a cylinder as possible. Especially on the top  of the part to allow it to be grabbed by the Chuck jaw.

My recommendation would be to use regular steel, and produce it using a manual lathe.

I have concern that aluminum would either deform or even melt with the use of rocket fuel.

And I would recommend against stainless as the extra expense doesn't really give you any additional thermal properties, and may actually be worse at handling the temperatures (I'd have to check)

You may want to look into making it out of ceramic instead, as the ceramic would be much better at handling the temperatures. But would also not like such thin walls.

Sent from my Samsung Galaxy , an AT&T LTE smartphone

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[john vanhoozer]

James brings up several very good points about materials.

I think that right now, I've had the most time on the metal lathe and I'd be happy to help turn this in Aluminum.  Remember that Aluminum melts at about 1200 degrees Fahrenheit  (630 Celsius). So your choice of fuel would help us know if Al will work for you.  A quick look on-line shows that Sugar Propellant/Rocket Candy will produce a flame of 1400F which would be Bad (TM)

Also :  Be warned, there are a host of laws regarding flying anything more powerful than an Estes (Solid) Rocket Motor type of launch.  I think those top out a an F or G series engine.  But if you are just going to strap the thing in to a harness and gather data on the performance, I don't think that's covered - but you really ought to check local codes and let the local Fire Department know what you're doing and when.  The youtube of the guy poring liquid Ox on a barbeque grill comes to mind...  The Fire Trucks showed up because of the huge amount of smoke.

FYI, if you don't know about this site, it's a really comprehensive one for rocketry Fu:  Jacob's Rocketry. Oddly enough, I ran across them back when I was looking for information on foam cutting (great co-site by the same people with info, parts, and NiChrome/Power/Heat calculator).  It seems that model rocketry, r/c models and such all need to cut a lot of foam.

[tookys3]

Another thing to consider is the type of fuel on the shape.

Will it be solid fuel or liquid fuel?

Solid fuel rockets at the hobbiest scale don't need the external nozzle, just the internal funnel.

Look at designed for the estees solid fuel rocket motor. They simply use a ceramic insert with a funnel shape for the nozzle inside a flat disc.

-> https://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Model-rocket-engine.svg/220px-Model-rocket-engine.svg.png

The larger nozzle designs like what you have, are for liquid fuel rockets as the fuel is still burning once out of the chamber and the nozzle is to help direct the flow of gasses as well as to produce more thrust from the continued burning.

-------

Yes some solid fuel rockets do use the larger nozzle design like you have, but those are usually doing so because they are using such large amounts of fuel that it can't all burn before leaving the chamber. 

See the solid rocket boosters on the space shuttle.

 

Sent from my Samsung Galaxy , an AT&T LTE smartphone

-------- Original message --------

From: john vanhoozer via 10BitWorks <sa-hackerspace+APn2wQfjxPZWSP-pS...@googlegroups.com>

Date: 7/23/17 11:05 AM (GMT-06:00)

To: 10BitWorks <sa-hack...@googlegroups.com>

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[Jose V]

Thanks, it's an APCP mixture. I've measured the flame at about 1070F.yes I've contacted the fire department and the FAA about the date of the launch.

[Jose V]

It's homemade solid mixture.

[Jose V]

Thanks, I'll look into a different material or wall thickness

[Randy Ohman]

Another option is fabrication. If you should be so lucky as to find one or both of the two basic shapes (perhaps easily turned to the final mate-up diameters), there is a lot of worth in processes that have already been done for you. For example, you  have a "cap" shape and "funnel" or "ferrule" shape. These are not uncommon drawn, stamped, spun or otherwise processed parts. The two could be welded, crimped, swaged or, if done considering the temperatures and expansive forces, press fit together.

[Randy Ohman]

Look in your favorite junk sources, sacrificial things, ready-made store available products that have the shapes that can be scavenged, etc. You'll find steel, stainless, and aluminum  common.

[Les Hall]

I haven't read all the responses, but just one question:  why don't you have it made a www.shapeways.com in aluminum?

Les

On Thu, Jul 20, 2017 at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[Les Hall]

also look at stainless steel, it is more affordable and you can select various coatings including gold.  

Les

On Sun, Jul 23, 2017 at 5:35 PM, Les Hall <deltamo...@gmail.com> wrote:

I haven't read all the responses, but just one question:  why don't you have it made a www.shapeways.com in aluminum?

Les

On Thu, Jul 20, 2017 at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR2-95hkDiWbnE3fbRvORFsN_utEy...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[john vanhoozer]

Oh, PLEASE let us know about the launch details!   I'd love to witness it!

[john vanhoozer]

I don't know what the cost would be, but it's a great idea to look in to.

On Sunday, July 23, 2017 at 5:35:19 PM UTC-5, Les Hall wrote:

I haven't read all the responses, but just one question:  why don't you have it made a www.shapeways.com in aluminum?

Les

On Thu, Jul 20, 2017 at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR2-95hkDiWbnE3fbRvORFsN_utEy...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[Les Hall]

Just go to www.shapeways.com, make an account, and click on any upload button you see.  I suggest trying stainless steel first as it is much more affordable.  Also you may wish to make the nozzle smaller if you can if the cost is too high.  

Les

On Mon, Jul 24, 2017 at 9:53 AM, john vanhoozer via 10BitWorks <sa-hackerspace+APn2wQfjxPZWSP-pS...@googlegroups.com> wrote:

I don't know what the cost would be, but it's a great idea to look in to.

On Sunday, July 23, 2017 at 5:35:19 PM UTC-5, Les Hall wrote:

I haven't read all the responses, but just one question:  why don't you have it made a www.shapeways.com in aluminum?

Les

On Thu, Jul 20, 2017 at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR2-95hkDiWbnE3fbRvORFsN_utEyIU...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[Les Hall]

That or I can list it for you if you like, I'll just require your permission.  

On Mon, Jul 24, 2017 at 12:07 PM, Les Hall <deltamo...@gmail.com> wrote:

Just go to www.shapeways.com, make an account, and click on any upload button you see.  I suggest trying stainless steel first as it is much more affordable.  Also you may wish to make the nozzle smaller if you can if the cost is too high.  

Les

On Mon, Jul 24, 2017 at 9:53 AM, john vanhoozer via 10BitWorks <sa-hackerspace+APn2wQfjxPZWSP-pSRk21jFEzuogDYmOH8ipIzGqE66tcBJ...@googlegroups.com> wrote:

I don't know what the cost would be, but it's a great idea to look in to.

On Sunday, July 23, 2017 at 5:35:19 PM UTC-5, Les Hall wrote:

I haven't read all the responses, but just one question:  why don't you have it made a www.shapeways.com in aluminum?

Les

On Thu, Jul 20, 2017 at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR2-95hkDiWbnE3fbRvORFsN_utEyIU...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[Jose V]

I've used up all my money I had to spend in this rocket. I was going to just get it on shapeway since it's super easy.

[Randy Ohman]

Excellent idea, if not cost prohibitive. A quote is warranted.

[Jose V]

It *MIGHT* be launched August 17 in the late afternoon. No Exact date yet. I got clearance to launch at 29.5629, -98.4542.

[Jose V]

Thanks, but I've used up all the money I have extra to put into this rocket. Might end up using a washer made of steel as a nozzle.

On Monday, July 24, 2017 at 12:07:37 PM UTC-5, Les Hall wrote:

Just go to www.shapeways.com, make an account, and click on any upload button you see.  I suggest trying stainless steel first as it is much more affordable.  Also you may wish to make the nozzle smaller if you can if the cost is too high.  

Les

On Mon, Jul 24, 2017 at 9:53 AM, john vanhoozer via 10BitWorks <sa-hackerspace+APn2wQfjxPZWSP-pSRk21jFEzuogDYmOH8ipIzGqE66tcBJ...@googlegroups.com> wrote:

I don't know what the cost would be, but it's a great idea to look in to.

On Sunday, July 23, 2017 at 5:35:19 PM UTC-5, Les Hall wrote:

I haven't read all the responses, but just one question:  why don't you have it made a www.shapeways.com in aluminum?

Les

On Thu, Jul 20, 2017 at 8:26 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR2-95hkDiWbnE3fbRvORFsN_utEy...@googlegroups.com> wrote:

I have this rocket nozzle that I modeled in OnShape. I need it made in metal but every company has refused to make it due to its complexity. Does anybody have any ideas? Maybe casting a solid model first then drilling the holes in it?

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[john vanhoozer]

Wow! That close to the airport?

Aug 17?   Hmmmm, I might not be able to - going to Tennessee to watch the eclipse.    But I'll keep it in mind.

How big is the bird you're going to fly and what kind of altitude do you expect?

[Jose V]

Not that big, 2feet long, 2in diameter. Computer simulations show around 7,000 feet.

[Sdfhg Sgh]

If you didn't know, i spent a couple years at a CNC lathe facility. I would design tools, and help in converting customers prints to something usable.

Looking at your design, we would either no quote, or give you a ridiculous price because we wouldn't want to make it either. 

Your part is close to a 6-7/10:1 ratio at the thin point in the nozzle, to the outer nozzle.

And a 25:1 ratio from the inlet to the outlet of the nozzle.

When designing turned products there is something known as the 3:1 rule, which in its simplest form, when you are turning a product, the amount of material stick out from a point shouldn't exceed 3 times the diameter at that point. For parts that are hollow you simply subtract the Inside diameter from the Outside Diameter, then the result is what you use as the diameter.

Max stick out = 3 X Dia.

Dia. = O.D. -  I.D.

(Yes i know you get a better result if you compare the cross sectional area, but the 3:1 ratio is more to do with wall thickness and less to do with the cross section)

Of course this rule can be broken its by no means absolute, but it is a good rule for quickly determining how difficult a part will be to produce. The larger the ratio the more likely the part is to flex during turning, and not hold the targeted diameter. At 3:1 we start taking a closer look, at 5:1 we start asking the customer to redesign the part.

I at times did work on parts with a 60:1 ratio, but they become extremely expensive and difficult to produce, requiring very special machine set-ups to handle them.

If the weight isn't a extreme concern you need to thicken your material. Also when looking at having internal angles inside a part each additional angle is an additional cost. So if you can use 1 angle instead of 2 for a feature it will reduce the cost of manufacturing.

(The small diameter for the nozzle has straight sides because if you want to have it be a known size you will want it to be drilled as a separate action, trying to get a constant size where to angles drilled from 2 separate chucking meet is extremely difficult and expensive, so if your nozzle opening is important, let it be a separate drilling operation. it wont add much to the cost.)

Beyond that its just a matter of being sure to relay the information you need to the manufacturer.

Attached is a print for a redesign i did of the engine. It holds about a 3-1/2:1 ratio, and allows for easy manufacturing.

I can't give you an estimate for price, but I'm certain that people will at least give you a quote using the design i produced.

Here is a link to the on shape document of the nozzle for you -> Onshape

Onshape

On Monday, July 24, 2017 10:09 PM, Jose V via 10BitWorks <sa-hackerspace+APn2wQddNianbYuwR...@googlegroups.com> wrote:

Not that big, 2feet long, 2in diameter. Computer simulations show around 7,000 feet.

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[Kevin Baldor]

Perhaps that's why they invented flowforming/metal-spinning https://www.youtube.com/watch?v=nChgn9mv3RQ

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[Jose V]

Thank you!

[Don Smeller]

Jose found a nozzle design on-line, downloaded it, found it was too big, and simply scaled it down.  

The wall thickness got to be a tad too thin.  The nozzle needs to be designed from scratch with lathe techniques in mind.

It ain’t rocket science.  Oh? Yes it is?  In the end, it’s the central orifice that matters most and then the diverging angle of the exhaust gases. 

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[john vanhoozer]

Well, Jose, I'm greatly bummed that I will not be able to witness the launch, since I will be travelling to see another event - the eclipse. 

I do hope that you will have video and let us all see the results!