Proline ARCAS / RRC3 Telematics - build thread

[MWC]

Having just received this new Proline Kit, I thought I would document "the build" (actually, the assembly) of this kit on the forums in tandem with the development and deployment of the new RRC3 Telematics System. Since the ARCAS was a sounding rocket in the "classic" sense, carrying the PWN-6A radiosonde (and other payloads), I thought it fitting that this sport ARCAS should have it's own "sonde payload".

First off, I had been eagerly awaiting the release of this ever since it was slated for production in the "Proline" roster... I got the word by virtue of Alex Zoghlins "PHP Script" post (https://www.rocketryforum.com/showt...H-END-KITS-AND-COMPONENTS&p=734821#post734821) in the Manufacturer's Forum that the kit was finally for sale (thank you Alex!). I immediately contacted Gary T thereafter and scored one of the first ten kits.

Let's start with the unboxing... the kit arrived in two separate shipments, one from Curtis, the other from Gary.




I opened the small box first:




This box was loaded with the cone/coupler, av-bay and bulkheads, sled, all-thread, MMT CR's and the NC bulkhead.
The ARCAS kit comes standard with the signature anodized aluminum bulkheads and charge canisters, and is set up for redundant avionics.
All these components and parts are top notch...




Now onto the big box, or what I am calling "booster in a box".
Here's the top after opening... notice the "box in a box" packaging and additional foam to stabilize the airframe.
The foam lining runs the full length of the box... the packaging was impressive.




Once this top foam/tape was removed I pulled out all the big box contents.
The fully assembled "booster", motor mount tube, and the motor retainer (GLR Slimline).
Tucked inside the Slimline bag was a custom allen-wrench, ground down to fit the fin fasteners.




In addition, complete "scale" vinyl lettering is included to finish your ARCAS in the "display and advertising motif".
(no ARCAS Bear, however).




After removing the foam fin covers, the beauty of this kit was truly revealed.




The powder coated all-aluminum fins and integral tail cone are truly gorgeous.




I upended the tail cone for closer inspection of the fin attachment.
The tailcone utilizes a machined aluminum endoskeleton structure epoxied in that is drilled and tapped for the mounting screws.
Not visible (but present) is an additional alignment pin that stabilizes each fin from any rotation.




I promptly grabbed a roll of masking tape for the obligatory "dry stack" of the rocket.




I have to say this is a very impressive full scale kit of a very iconic rocket (now all I need is the scale breech launcher).
Stay tuned as this build (or assembly) progresses.

 

[Cory]

Thanks for doing this thread, I too have been yearning for this kit, since I first saw the advertisement in ROCKETS. I recieved the email from Gary T. shortly after making a motor order, so no dice for the time being. Good luck on the "assembly", any thoughts on the first flight motor and where you plan to fly?

 

[DizWolf]

an amazing rocket for sure, that I wish I could get into my collection.

So tell me more about the electronics *drool*

 

[cwbullet]

It sure looks pretty.

 

[iqsy59]

Eagerly watching...

 

[blackbrandt]

Cool...

 

[MWC]

Good luck on the "assembly", any thoughts on the first flight motor and where you plan to fly?

I'm considering building a "hack" version... I'll need to plug in some new mass items into the model, but strongly considering 75mm motor conversion. Motor would load from the av-bay "body break" and be internally retained. I fly here in CO with NCR (Northern Colorado Rocketry), and most likely it will get its maiden loft there. There's a small chance it could fly at BALLS as I am making the sojourn back out there this year (after a 9 year absence).

 

[Bat-mite]

Fun thread.

 

[H_Rocket]

...and deployment of the new RRC3 Telematics System. Since the ARCAS was a sounding rocket in the "classic" sense, carrying the PWN-6A radiosonde (and other payloads), I thought it fitting that this sport ARCAS should have it's own "sonde payload".

Ears up!


Tell us more.

 

[4kids49]

Nice Jim. Looking forward to the build and the Telematics.

 

[crossfire]

I was surprised to see black tubing for the kit. Gary T. Can you build them with white tubing?

 

[Spicer007]

Great looking kit, I'll be watching...

 

[MWC]

OK, I did some poking around in Open Rocket.

It looks like the worst case CG/CP stability margin would be with a motor along the lines of the AMW L1060 75mm motor (75-3500 casing).
It falls just below the 1 caliber comfort zone, however there are no static mass items for electronics, harnessing, etc.
Thus I believe that 75mm hack of this kit will be "flyable".



The entire motor mount assembly would have to load from the drogue airframe break vs. traditional "business-end insertion", but it is feasible.
I've currently got a pair of custom aluminum rings in the model and a standard 3.1 FWFG MMT... still undecided on the finer details (thrust transfer/retention).
Also I'm a bit concerned over heat at the boat tail end of the airframe.

A quick "test" using tubes and motors revealed the fin mounting screws need to be a bit shorter... not a huge deal there.
Still cogitating over propulsion for this... "one can always adapt down".

 

[cwbullet]

Parts are gorgeous. I love this kit. I need one more part, a retainer, and rail buttons.

 

[Kaycee]

I love the ARCAS. How did I miss this kit?

 

[Blastcap Rocketry]

A Bit concerned?? You'll end up burning off the boat tail off and probably some of the fins. Wait for the HV ARCAS with it 98mm MM.

 

[Kaycee]

A Bit concerned?? You'll end up burning of the boat tail off and probably some of the fins. Wait for the HV ARCAS with it 98mm MM.

Gary, THAT'S the one I want!

 

[Coop]

Very impressive! Glad to see you guys who ordered have received yours!


Later!

--Coop

 

[Reinhard]

OK, I did some poking around in Open Rocket.

It looks like the worst case CG/CP stability margin would be with a motor along the lines of the AMW L1060 75mm motor (75-3500 casing).
It falls just below the 1 caliber comfort zone, however there are no static mass items for electronics, harnessing, etc.
Thus I believe that 75mm hack of this kit will be "flyable".

View attachment 180212

The entire motor mount assembly would have to load from the drogue airframe break vs. traditional "business-end insertion", but it is feasible.
I've currently got a pair of custom aluminum rings in the model and a standard 3.1 FWFG MMT... still undecided on the finer details (thrust transfer/retention).
Also I'm a bit concerned over heat at the boat tail end of the airframe.

A quick "test" using tubes and motors revealed the fin mounting screws need to be a bit shorter... not a huge deal there.
Still cogitating over propulsion for this... "one can always adapt down".

You need to ensure the the nozzle is not recessed from the aft end. Besides the thermal issues, a recessed nozzle can cause performance issues when the exhaust interacts with the airframe. It is my understanding, that this is also the reason why the Pro75/Pro98 tail cones are only available for loads that use the XL nozzle. Based on the external drawings, it looks like these loads might work with the ARCAS.
https://www.pro38.com/pdfs/Pro75_dimensions.pdf (page 2)

The situation with AT motors is probably the same:
The M-1850 looks like it might work:
https://www.aerotech-rocketry.com/u...b-bf3e-273573d2d562_75-7680_m1850w-p_assy.pdf
The M-685 will likely fry the end of your rocket and might perform not as expected:
https://www.aerotech-rocketry.com/u...4e-ad2b-84dff8b3b9ac_75-7680_m685w-p_assy.pdf


Reinhard

 

[MWC]

You need to ensure the the nozzle is not recessed from the aft end. Besides the thermal issues, a recessed nozzle can cause performance issues when the exhaust interacts with the airframe. It is my understanding, that this is also the reason why the Pro75/Pro98 tail cones are only available for loads that use the XL nozzle. Based on the external drawings, it looks like these loads might work with the ARCAS.
https://www.pro38.com/pdfs/Pro75_dimensions.pdf (page 2)

The situation with AT motors is probably the same:
The M-1850 looks like it might work:
https://www.aerotech-rocketry.com/u...b-bf3e-273573d2d562_75-7680_m1850w-p_assy.pdf
The M-685 will likely fry the end of your rocket and might perform not as expected:
https://www.aerotech-rocketry.com/u...4e-ad2b-84dff8b3b9ac_75-7680_m685w-p_assy.pdf


Reinhard

Thanks for the motor drawing references. I hadn't started examining the physical aspects of CTI or AT motors to see if they would be good candidates, and your drawing refs certainly are a great starting point. The exercise up until now was solely to ensure there'd be enough of a stability margin to feasibly continue, and I believe there is based on the poking around I have performed.

The concern I expressed previously, and as both you and GT have echoed are the thermal concerns. I have several 75mm motor casings (AMW and Purple Woody's) and it's apparent that the heat flux in the divergent exhaust of a "Kosdon Classic" casing style would have damaging effects without some additional insulated protection. Any additional thermal protection would restrict the ID of the boat tail further (a bad thing in this instance).

There's ~ 1.5" of tail cone that is aft of a 75mm MMT if positioned flush to the inner wall of the boat tail. In practical terms a 75mm MMT would need to sit ~2" from the boat tail exit to allow an aft AT or CTI motor closure. I'll need to look closer at the nozzle dimensions relative to the aft closure for these style cases. The M-1850 AT style appears to be the most workable as the nozzle protrudes ~1.25" out from the aft closure. That still leaves ~0.75" of airframe tail cone "exposed".

I also can't speak to the effects of the interaction of a recessed nozzle in a boat tail, but intuitively it suggests additional complications as you point out.

I'm starting to doubt the practicality of moving forward with 75mm propulsion...

 

[beezwax]

In addition to burning your butt, isn't recessing the motor that far into the boattail likely to bring on the Krushnic effect?

https://www.nar.org/pdf/TCR1.pdf

 

[Reinhard]

I have several 75mm motor casings (AMW and Purple Woody's) and it's apparent that the heat flux in the divergent exhaust of a "Kosdon Classic" casing style would have damaging effects without some additional insulated protection. Any additional thermal protection would restrict the ID of the boat tail further (a bad thing in this instance).

If you fly research, another option might be a blast tube.
https://www.rocketryforum.com/showthread.php?17279-why-using-blast-tubes

There doesn't seem to be much practical experience with these outside professional circles, so I'd expect some "lessons learned" along the way. That's probably not the thing that you have in mind for a nice kit like the ARCAS.

Reinhard

 

[pyrobob]

Wow, that really is a very nice kit. Thanks for sharing.

 

[markkoelsch]

Jim, the kit is beautiful- I would not mess with it to go to the larger motor mount. You do not want a recessed engine, and the heat will damage the rocket.

You could always build a different rocket as your test bed.




Mark Koelsch
Sent from my iPhone using Rocketry Forum

 

[MWC]

After much consideration and discussion, I've opted to build this with the stock 54mm MMT. I've looked at additional motor sims, and I can get some decent altitude/performance on larger K's and L's. Thanks to everyone who weighed in... your rationality prevailed.

With that out of the way I'll start on the assembly of this kit over the weekend.... spending my evenings getting a jump on the Telematics project.

 

[ColumbiaNX01]

I bought a Arcas aswell! I got it in the mail within the last week. I am excited to build it. How are you building yours? R u gluing slimline on first then gluing on CR and gluing whole thing in at once or are you waiting and gluing the slimline in last. IDK which way I am planning.

 

[MWC]

I bought a Arcas aswell! I got it in the mail within the last week. I am excited to build it. How are you building yours? R u gluing slimline on first then gluing on CR and gluing whole thing in at once or are you waiting and gluing the slimline in last. IDK which way I am planning.

Andrew -

I discussed this exact procedure with Gary T. as well as coming up with a few ideas myself, so here's my current thoughts regarding MMT installation.
I'm leaving out all the surface prep steps and will touch on the main strategy:

- Glue the Slimline retainer on the MMT (JB Weld)
- With the lower airframe vertical on a 100% flat surface, slide in the MMT and the lower CR
- Tack the lower CR to the MMT with CA or 5min epoxy
- Once tack is set, remove MMT and lower CR

When you drop in the MMT and lower CR, it will rest on the upper fin alignment pins. The Slimline will also be flush with the aft end of the boat tail. All in all this is a good starting point for getting everything true and referenced. From this point however I'm still debating how the entire assembly gets anchored. A few thoughts here are:

- Glue/Fillet on the additional CR's to the MMT to complete the assembly and let it cure
- Suspend the lower airframe on a temporary symmetrical rope/cord harness you can suspend somewhere
- Prepare a thickened or reinforced batch of epoxy (almost peanut-butter consistency) and apply this to the "nose" surface of each CR along the outer circumference
- Slide the MMT assembly into the lower CR carefully (keep vertical)
- Once inside, spin the lower airframe repeatedly to ensure the applied epoxy makes good contact with the inner airframe walls

Of course, one should have also made plans for rail guide and lower airframe harness anchor points before committing to MMT assembly.

I'm the type that "really" likes to use fasteners for as many things as possible in my rocket designs, so there's also the possibility of anchoring the entire MMT assembly with a "bolt circle" along the top CR. This of course would create a "non-scale" bolt circle, however that would match with the airframe fasteners I'll be using to anchor the av-bay coupler to the upper airframe section.

As mentioned above, I am still debating on the method I'll use... the one thing that's certain is the Slimline will be JB-Welded to the MMT. I'd like to hear your thoughts on assembly as well.
I know there are "others" with this kit on the forums. Please chime in and collaborate.

 

[blackjack2564]

Take a break.... drink some Grog.... think .............it will all become clear!

How clear is proportional to amount of Grog consumed.

 

[ColumbiaNX01]

My thoughts are as followed:

Glue slime line on with jb weld
Do the same like u, slid MMT and CR into rocket form the forward end
Once the slimline is flush with aft end tack CR to MMT with CA
Pull out entire assembly
Measeure the entire MT and glue CR in an even distance apart.
Once you have the slimline and 3 CR cured to MT with epoxy fillets slide entire assembly into rocket from forward end
Tack in Motor mount to aiframe using CA
Once tacked put a nice epoxy fillet on top of forward CR and fillet on bottom of aft CR
From this point on you have a semi attached MMT
Since the rocket is gonna be painted I will drill holes in airframe between the CR, so there will be 2 holes.
I Will use aeropoxy and a syrenge to shoot epoxy into rocket. Creating a epoxy fillet on each side of CR. It will take some time, a few days for the epoxy to fully cure.
As a result, the bottom CR has fillet on each side, middle CR has fillet on each side, and top CR has epoxy fillet on each side.
Once cured I will foam the entire fin can with expanding foam between aft and middle and between middle and forward.

Since this is a 54mm mount I see no reason to try and even attempt to fly on big 38mm I use the Aerotech forward tapped closure for recovery retention.

Also, I know doing it this way will cover the retaining aluminum ring that fins bolt to in epoxy. I still am figuring out a way to do that or not to do that.

 

[MWC]

My thoughts are as followed:

Glue slime line on with jb weld
Do the same like u, slid MMT and CR into rocket form the forward end
Once the slimline is flush with aft end tack CR to MMT with CA
Pull out entire assembly
Measeure the entire MT and glue CR in an even distance apart.
Once you have the slimline and 3 CR cured to MT with epoxy fillets slide entire assembly into rocket from forward end
Tack in Motor mount to aiframe using CA
Once tacked put a nice epoxy fillet on top of forward CR and fillet on bottom of aft CR
From this point on you have a semi attached MMT
Since the rocket is gonna be painted I will drill holes in airframe between the CR, so there will be 2 holes.
I Will use aeropoxy and a syrenge to shoot epoxy into rocket. Creating a epoxy fillet on each side of CR. It will take some time, a few days for the epoxy to fully cure.
As a result, the bottom CR has fillet on each side, middle CR has fillet on each side, and top CR has epoxy fillet on each side.
Once cured I will foam the entire fin can with expanding foam between aft and middle and between middle and forward.

Since this is a 54mm mount I see no reason to try and even attempt to fly on big 38mm I use the Aerotech forward tapped closure for recovery retention.

Also, I know doing it this way will cover the retaining aluminum ring that fins bolt to in epoxy. I still am figuring out a way to do that or not to do that.

Very nice. I had similar thoughts regarding injection, but instead of injection holes that would require patching I had considered trying to incorporate the rail guide mounting holes into "dual use". The issue with this is I'd like a hardware backer for the rail button screws. Agree as well that considering a non-plugged motor closure is a non-starter, thus there's always the use of that hard point anchor.

Take a break.... drink some Grog.... think .............it will all become clear!

How clear is proportional to amount of Grog consumed.

WWCJD?
I agree with the Grog philosophy... and tomorrow is our neighbors "rites of summer" pig roast just a few houses down.
Grog and Suds consumption galore!