3.72" Proteus Downscale

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patelldp
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3.72" Proteus Downscale

Postby patelldp » Fri Nov 06, 2015 8:46 am

I have always loved the Hawk Mountain Proteus. It's a classic design made out of quality materials with exceptional workmanship. When a built Proteus became available on TRF last year I HAD to jump on it. I refurbished it and brought it to LDRS in Potter, NY to fly on a Research 98/4G M2225 Plain Jane of my own making:

IMG_4869.jpg
IMG_4869.jpg (864.92 KiB) Viewed 2810 times

Photo by Todd Harrison. Thanks Todd!

Fast forward a year to when I found a large stockpile of 3.72" Filament Wound Fiberglass tubes in Amsterdam, NY. These tubes aren't hobby-standard dimensions (they are 3.715" OD and 0.05" wall), but the quality was good enough that I had to have them. After staring at them for some time, I decided to sell several of them coupled with a custom made 3D printed nose adapter to permit the use of standard 3" hobby nosecones. I sold ~20 of the tubes, leaving me with just over 10 to use for myself...enter this project!

The rocket will use one 48" tube for the booster and 30" for the payload section. A 24" long FWFG motor mount for 76mm motors resides in the booster and is centered by the beautifully CNC routed 3/8" ply centering rings done by Nat Kinsey at UpscaleCNC (natkinsey@gmail.com). We'll get to those later!

The first effort in this build was the fins. The material used is a 0.120" carbon fiber plate of unknown origin. The plate's thickness lends to incredibly stiff fins and the price was right, so I decided to put it to use on this project. First, I cut the fins with a Harbor Freight angle grinder and 1/16" cutoff wheel:

Fins - 1.jpg
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I then sent the fins off to Mike at MAC Performance Rocketry to do my bevels. They should be arriving tomorrow, but in the mean time here's the teaser pic he sent me (THEY LOOK GREAT!):

Fins - 2.jpg
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I plan to follow up with pictures of each step. The nosecone will be an interesting endeavor, so be sure to stay tuned!
Dan Patell
TRA 10904 L3

Pitter
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Re: 3.72" Proteus Downscale

Postby Pitter » Fri Nov 06, 2015 3:02 pm

I recognize that working surface in the air foil picture, very nice workmanship!

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patelldp
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Re: 3.72" Proteus Downscale

Postby patelldp » Fri Nov 06, 2015 5:06 pm

Pitter wrote:I recognize that working surface in the air foil picture, very nice workmanship!


Thanks! I'll be uploading some more pictures tomorrow. It's my goal to slot the tube tomorrow, but we'll see how that goes. I need to go through the effort of squaring all of my tubes and couplers to assure everything fits together nicely. Hopefully this turns into a nice rocket that can fly on a variety of motors.
Dan Patell
TRA 10904 L3

RKeller
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Location: Gorham, NY

Re: 3.72" Proteus Downscale

Postby RKeller » Fri Nov 06, 2015 7:52 pm

sweet. where did you get your carbon? I just ordered some 1mm matte finish carbon for a 29mm MD build I'll be doing this winter. ordered it from some hong kong supplier. should have it by winter. :roll:
Riley Keller
URRG
TRA#15415
L1 25 Oct 2014 Estes MDRM CTI H133
L2 25 June 2015 Rocketry Warehouse DYOK, CTI L1030RL 14.7k ft mach 1.57

I'm addicted to building stuff, rockets are just a way to get high 8-)

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patelldp
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Re: 3.72" Proteus Downscale

Postby patelldp » Fri Nov 06, 2015 9:29 pm

Riley,

Got the carbon from Eric Stackpole at the last CTRA launch. I have a 6"x6"X.0625" dragon plate if you need something before winter...
Dan Patell
TRA 10904 L3

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patelldp
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Location: New York

Re: 3.72" Proteus Downscale

Postby patelldp » Sat Nov 07, 2015 8:51 pm

Received my fins from Mike today, and they're as gorgeous as the pics he sent suggested! More on that later.

Not a whole lot accomplished on this rocket...basically that means nothing has been accomplished. On a happy note, my wife and I have combined for removing 100 yard bags of leaves from our property so far this year. I predict there's another 125-130 to go...

On ANOTHER happy note, I finished kitting up a tube fin rocket for a repeat customer using the same tubing as this project. Here's what it looks like:

Tube_Fin_Kit.jpg


More to come!
Dan Patell
TRA 10904 L3

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patelldp
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Location: New York

Re: 3.72" Proteus Downscale

Postby patelldp » Sat Nov 07, 2015 10:56 pm

Here's some more pictures for your enjoyment...

First up are the motor mount parts. Booster is 48", 76mm motor tube is 24" long. The motor tube is standard thickness FWFG from Rocketry Warehouse and is of incredibly high quality. I was VERY impressed when I opened the box, it's one of the best fiberglass tubes I've ever seen. The centering rings are from UpscaleCNC (Nat Kinsey) and are exceptional as well.

image.jpeg


So let's zoom in on these bevels from Mike. These bevels are stock on all of his kits...you really, really get what you pay for! Outstanding job, and will certainly improve the aesthetics of this build versus what I would have been able to do!

image.jpeg


image.jpeg


Let's see that back end with the motor mount in there...not a whole lot of extra room!

image.jpeg


Final picture for the night is an interesting coincidence...the AeroPack 76mm retainer cap OD is almost identical to the OD of my 3.72" tubing! It's slightly smaller, so it's a great option...but will I use it?

image.jpeg
Dan Patell
TRA 10904 L3

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CrankyKOng
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Re: 3.72" Proteus Downscale

Postby CrankyKOng » Sun Nov 08, 2015 2:54 am

patelldp wrote:Received my fins from Mike today, and they're as gorgeous as the pics he sent suggested! More on that later.

Not a whole lot accomplished on this rocket...basically that means nothing has been accomplished. On a happy note, my wife and I have combined for removing 100 yard bags of leaves from our property so far this year. I predict there's another 125-130 to go...

On ANOTHER happy note, I finished kitting up a tube fin rocket for a repeat customer using the same tubing as this project. Here's what it looks like:

Tube_Fin_Kit.jpg


More to come!

Nice looking tube fin kit!
Cranky Kong, Certified Rocket Monkey
"We were promised jet packs!"

2015: Total Impulse: 2,017.78 Ns - 58% K motor
Since 2010: Impulse: 11,019.58 Ns - 8% N motor

pshooter26
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Re: 3.72" Proteus Downscale

Postby pshooter26 » Mon Nov 09, 2015 12:01 pm

aeropack.jpeg
aeropack.jpeg (33.19 KiB) Viewed 2708 times



Of course you will :D

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patelldp
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Re: 3.72" Proteus Downscale

Postby patelldp » Tue Nov 17, 2015 10:06 am

Back at it! I've had some business travel get in the way of progress on this project.

This morning before work (I work from home) I printed out a fin guide from http://www.payloadbay.com to start marking fin slots on my tube. These are great guides as the price is right (free!) and they're accurate.

IMG_3089.JPG


Once the end of the tube was marked, the lines are extended up the tube with some angle aluminum. I also marked the ends of the slots with circumferential lines and added a second line 1/8" away from the first line to complete the slot perimeter.

IMG_3090.JPG


This is why I love transparent glass tubes without any color pigment added...you can confirm that the spacing of your CR's is correct before any epoxy is mixed! It also allows you to confirm that you have a good epoxy joint at the CR/tube attachment points. Put bluntly, pigmented tubing sucks.

IMG_3091.JPG


For this build, I am strongly considering the tried-and-true method of extending the slots all the way to the aft of the tube to allow me to slip the motor mount/fin assembly out of the tube for internal filleting. The area between the body tube and the motor tube is ~0.25", leaving little to no area to work with if I were to try to add epoxy from the aft end of the tube. I could try the "hole and syringe" method, but I fear the same will be true. This method may still be employed for the internal body to fin fillet once the assembly is permanently installed...we'll see!
Dan Patell
TRA 10904 L3


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