LOC Vulcanite vs Estes Partizon build challenge

The recent discussion over the question "why build heavy mid-power rockets" has led to the thought that, to some degree, many of the opinions on the subject could be real-life tested comparing a "heavier" and "lighter" kit from build through launch.

Would anyone be interested in a parallel build thread of the very-similar LOC Vulcanite and Estes Partizon kits?


This would not only cover the builds comparing structures, build technics and costs but also performance and survivability aspects including drag races with similar motors over numerous launches.

If the answer is yes, then I'm going to need the assistance over time of fellow rocketeers (preferably younger ones who would enjoy participating and would benefit from the educational aspects). They would help sort out the advantages and disadvantages at each step of the way and perform analysis and projections (using OpenRocket, RockSim, etc.) and launch duty while collecting in-flight data at high power launches near the San Jose area (LUNAR Snow Ranch, TCC Maddox Dairy, etc.).

The kits would be built close to stock although the Vulcanite will benefit from the ability for dual deploy using a cable cutter. We could share the results here and start who knows how many more rounds of discussion. Anyone interested?

Let's start with the specifications and features of each model:


Dimensionally the models are similar. The Partizon is a little taller at 56" compared to 53.3" for the Vulcanite. The Partizon is also a little wider with a diameter of 2.5" versus 2.26 for the Vulcanite.

Standing next to each other,dry fitted.

Here are the parts for each kit when laid out. The Vulcanite is on the top.


Looking at the sizes and then the respective weights is the first indicator that the Vulcanite is designed to handle increased flight loads. Its weight is 23 oz, nearly 4 oz more than the larger Partizon. This is mainly due to the thicker walled body tube and stouter nosecone (3.7 oz vs 2.5 oz).


Therefore, it may be no surprise to see that LOC advertises the Vulcanite as a high flyer with the included 38mm motor mount. The Partizon, with its 29mm motor mount, is advertised to ascend to 1800 ft with a G80-7 whereas the Vulcanite with an H242-12 is claimed to reach over 3500 ft.


Retail price of the kits: $69.99 for the Partizon, $74.75 for the Vulcanite.

I'm gonna follow this.

Yeah ... interesting.

Very cool, I'll be watching.

Nate

As will I


Sent from my iPod touch using Rocketry Forum

Other Items

Each kit came with a pouch full of goodies that help complete the build.

The Partizon came with a 24" nylon chute, 8 ft of bungee cord, two one-inch long 1/4" ID launch lugs, an Estes 29mm plastic motor retainer, a 29mm OD motor block and a spacer ring. Amazingly, when Estes upscaled to the PSII series, they still incorporated the paper-wrap-bungee-glue-to-the-inside-wall technique to retain the parachute and nose cone from ejection to landing.


The Vulcanite came with a 26" nylon chute, 8 ft of bungee cord, one six-inch long thicker-walled 1/4" launch lug, a bulkhead plate assembly and a curious shock cord mount. In the photo there are a few items I added - a third 38mm centering ring and two options for the motor retainer. The third centering ring ($4.75) will allow the fins to be better bonded to the motor mount. As the kit comes with no motor retainer (and I prefer not to wrap motors with tape) there is the ubiquitous black metal Aero Pack RA38L 38mm retainer ($29.00) or the Home Depot hand made 1-1/2" PVC pressure coupling retainer ($7.52 - makes two retainers, so only $3.76 for one) that requires a hefty amount of work to make fit a 38mm motor tube.

Mr G said:

....The Vulcanite came with ......a curious shock cord mount....

Click to expand...

The LOC shock cord mount is extremely strong. I treed a 2.6" rocket really good and managed to snag the shock cord with our 40' tree pole and two 200 pounders with feet off the ground bent the tree over 90 degrees but could not break the shock cord mount, the recovery gear or the rocket. The rocket stayed in the tree for at least 6 months.....That's one strong method of epoxying a shock cord mount to an airframe!

Bob

Both motor mounts will get the same shock cord bridle treatment. A small hole is drilled through the upper centering ring where in a later step a length of 1/8" Kevlar cord will be slipped through and epoxied to the motor mount. Before gluing anything, the motor mounts are scuffed up with some sandpaper to provide a better bonding surface. The middle centering ring is checked against the body tube cut out and fin to assure correct spacing before gluing. The Estes centering rings are loose on the motor mount tube so they are tacked in place with super glue. Otherwise, instructions are followed indicating white glue for the Estes, epoxy for the LOC.

Shock cord attachment


Both got the same treatment using the 1/8" 750 lb test Kevlar cord (15 cents a foot from Fuddrucker) wrapped around and epoxied to the motor mount.

First, the cord was cut to allow a loop to be tied above the top of the booster where a carabiner will be placed to allow quick change of shock cord/parachute assembly. The cord was then threaded through the previously drilled hole in the top centering ring and held back.

Epoxy was laid along the bottom of the centering ring and then down the motor mount tube to the next centering ring. The cord was then pressed into the epoxy and a piece of tape applied to hold everything in place against the tube. Simple, quick, strong, light and cheap.

For a while I was using forged steel eye-bolts and u-bolts on mid power rockets but they are way overkill in my opinion for the loads these light weight airframes are subjected to and really add a lot of additional weight. I do prefer Kevlar coming up from a centering ring and keeping the inner wall of the booster tube clear of any obstructions.

Mr G said:

Therefore, it may be no surprise to see that LOC advertises the Vulcanite as a high flyer with the included 38mm motor mount. The Partizon, with its 29mm motor mount, is advertised to ascend to 1800 ft with a G80-7 whereas the Vulcanite with an H242-12 is claimed to reach over 3500 ft.

Click to expand...

Shove a J530 in that hole, I guarantee the loc vulconite will go a whole lot higher then that Estes kit, and it will return in one piece. I think I got 8600 feet.

cbrarick said:

Shove a J530 in that hole, I guarantee the loc vulconite will go a whole lot higher then that Estes kit, and it will return in one piece. I think I got 8600 feet.

Click to expand...

Stock or did you beaf it up?

What would happen with similar reloads in the respective rockets? To the left is an Aerotech I200W reload with the corresponding 29/360 case for the Partizon. To the right is an Aerotech I161W reload and a 38/360 case for the Vulcanite. The reloads have virtually the same total impulse (324.5 Ns vs 328.7 Ns).

Would the stock Partizon survive such power? What issues come from the top third of the case sticking out of the motor tube? Assuming it did survive, would it win a drag race with the Vulcanite? Which one would fly highest? Are there different performance characteristics between the 29mm and 38mm reloads even though they have almost the same total impulse?

Mr G said:

View attachment 174357
What would happen with similar reloads in the respective rockets? To the left is an Aerotech I200W reload with the corresponding 29/360 case for the Partizon. To the right is an Aerotech I161W reload and a 38/360 case. The reloads have virtually the same total impulse (324.5 Ns vs 328.7 Ns).

Would the stock Partizon survive such power? What issues come from the top third of the case sticking out of the motor tube? Assuming it did survive, would it win a drag race with the Vulcanite? Which one would fly highest? Are there different performance characteristics between the 29mm and 38mm reloads even though they have almost the same total impulse?

Click to expand...

As Cbarick stated above, a Vulcanite will take bigger motors before failing in flight. That said, I have flown my Partizon on a H135W without issue; and have flown the Argent on an H268R (the red for the 29/360 hardware) twice without issue. The Partizon is just as sturdy as the Argent, so it should eat an I200W without issue.

Regarding performance characteristics; all else being equal (propellant, total impulse, chamber pressure, etc.), a smaller diameter motor will have a shorter burn time than the larger diameter motor due to a smaller propellant web (distance from core to OD of grain). Looking at the thrust curves on thrustcurve.org, the I200W burns for 1.7 seconds while the I161W burns for 2.0; both great motors by the way...I've burned a bunch.

Nice comparison; both really great rockets!!!

-Eric-

I'm on Team Estes when the Partizon is on sale.

majordude said:

Stock or did you beaf it up?

Click to expand...

Now why would you do that? It is straight stock with wood glue, not epoxy. All that noise about glassing and epoxy is NOT needed, unless your plan is to walk on top of it after it lands

cbrarick said:

Now why would you do that? It is straight stock with wood glue, not epoxy. All that noise about glassing and epoxy is NOT needed, unless your plan is to walk on top of it after it lands

Click to expand...

I disagree. I had a Vulcanite that I glassed, and I flew it for about thirteen years before parking it atop several trees. It took a pounding that I doubt it would have without the glass including finding the lone fence post amongst a filed of several hundred acres, landing in a swamp, landing on a road, and general handling.

Mine was extended a little to add dual deployment. It flew on everything from a g80 to a j570.


Sent from my iPad using Rocketry Forum

Launch lugs

On the Partizon, the provided launch lugs will be used. But to avoid possible rod whip and to take full advantage of slow burning reloads like the Aerotech I49N, rail buttons will be installed on the Vulcanite.

There isn't much room between the booster tube and engine mount to screw in the buttons. And to make finishing and painting easier and to be sure the buttons don't rip out, threaded inserts will go in first. This brings up some challenges.


If the threaded insert were installed to be flush with the outside of the body tube, it appears the other end would be flush with the inside of the motor mount tube. What are the issues with heat generated from the motor and insulating properties of the cardboard tube? Metal on metal could focus a lot of heat on one area. Might not be good for the motor case.

One solution might be to raise the threaded insert a bit with a shim to keep it off the motor mount. How much more drag would a 1/8" shim under the rail button cause? Would making it a teardrop shape really make any difference in drag?


Any other ideas?

Mr G said:

Any other ideas?

Click to expand...

The Vulcanite is light enough that you can just thread them into the cardboard. Drill your hole, CA it, clean it out, thread in the button, done.

daveyfire said:

The Vulcanite is light enough that you can just thread them into the cardboard. Drill your hole, CA it, clean it out, thread in the button, done.

Click to expand...

+1

I've done this on 6" airframes on M's.

Complexity equals time - rail buttons and minimum diameter

Thanks daveyfire and patelldp for keeping this from turning into more than it needed to be. Even with advise, thinking about how to do it turned out to take 90% of the time which was, in total, probably way overkill. The need to build up confidence that a never-tried-before procedure will go as planned can be time consuming.

Using scrap balsa, two small 3-ply squares were built up, drilled and sanded to match the contour of the space between the motor mount and body tube. With the motor mount along the outside of the booster tube and the balsa squares held in place, the booster was marked for where the rail buttons would be placed. Two holes just smaller than the diameter of the threaded insert was drilled in the booster tube and the upper balsa square was glued to the inside of the booster tube using a dowel. The dowel was marked so it was easy to see when the balsa square was aligned with the upper insert hole. A small piece of blue painters tape held the square on the dowel. Once dry, a little twisting of the dowel broke the tape bond from the square and the tape came right out. Since the lower centering ring would not be glued in until after the fins had been attached, the lower balsa square was epoxied to it.

The motor mount assembly was then epoxied in place with the use of a "glue gun" made of scrap wood and tape with the right angle bottoming out at the proper distance to assure the epoxy was spread at the correct distance in for the top centering ring to have a good seal.

With the motor mount fitted, the threaded inserts were temporarily screwed in to provide proper alignment for the rail button standoffs to be super glued in place.

Cool builds. I'm subscribed.

Another "glue gun" for applying white glue to the inside of the Partizon booster tube. A dab of glue was placed repeatedly on the end of the gun as the gun was inserted, the glue spread in a 1/2 inch ring around the inside of the body tube. The first ring was at the top (see pencil markings on the booster tube) and the second was above the fin slot. Inserting the motor mount and leaving about an inch of the motor mount still sticking out, a small amount of glue was applied between the fin slots so that as the last centering ring was pushed in there would be glue contact at the base of the fin slots and on the centering ring's upper surface without getting any glue where the fins would go in.

From a lesson learned the hard way, white glue comes in several flavors - some dry faster than others. Using a slower drying version is especially helpful when inserting motor mounts in body tubes where there is a close fit and there needs to be time for alignment adjustments. Titebond III has a 10 minute open time vs 5 minutes for Titebond I and II before the glue sets up and you can no longer make adjustments. Those extra 5 minutes make a big difference so that your work doesn't get permanently "frozen" before everything is perfectly lined up!

Mr G said:

Each kit came with a pouch full of goodies that help complete the build.

View attachment 172730
or the Home Depot hand made 1-1/2" PVC pressure coupling retainer ($7.52 - makes two retainers, so only $3.76 for one) that requires a hefty amount of work to make fit a 38mm motor tube.

Click to expand...

Could you please elaborate on the pressure coupling as a PMR?

Thanks
Ed

Ed,

Check these links for info on the PVC retainer:

https://www.rocketreviews.com/next-1435.html
https://www.rocketreviews.com/scratch-twice-removed-from-yesterday-by-dick-stafford.html


And here is one with a bunch of different ways to do it:

https://www.rocketryforum.com/showthread.php?11902-Homemade-Motor-Retainers

Coming up soon is the filleting of the Vulcanite fins between the inner body tube and motor mount. There isn't much room (3/8 inch maybe) to reach into the space to apply the epoxy.

Any suggestions on a simple way to get a good bond without making a huge mess or using way more epoxy than necessary?

Put dollops of viscous epoxy on a chop-stick and use that to goop the internal joints.

Numerous posts have covered the value of cleaning off and roughing up nose cones so paint will stick. Here are the Partizon and Vulcanite nosecones ready for their rub-down with rubbing alcohol.


Once that has dried, any seam or other protruding mold mark above the nosecone shoulder is sanded down until flush. The whole nosecone above the shoulder then gets rough sanded (I used 100 grit sandpaper).

Here is the Vulcanite nosecone with a coat of Bondo over where the main seam was that always seems to get ground down past round. If you blow up the photo you can probably see how rough the nosecone surface is. That assures the primer will stick.

Attaching fins always seems to take forever. Whether its slow drying white glue or the triple joint treatment for internal filets, there are just lots of pauses between applications. C'est la vie.

The Partizon fins first get a coat of white glue on the bottom thick enough so when they are placed through the slot in the booster tube the inner sides of the slot are coated. Once the glue has dried (setting all day or overnight), filets are carefully squeezed out of the glue bottle with a little touch up with a coffee stir stick to smooth everything out. The white glue shrinks considerably but the footprint against the fins and tube remain the same width.


The Vulcanite fins start out the same way but with epoxy. The tape helps protect from ham-fisted application of sticky epoxy that invariably would get all over the place and assures the filets are reasonably uniform. There is a magic moment when the epoxy begins to harden when the tape is removed. Too soon and strings of molasses-like glue will stretch and then fall between the tape and surface. Too long and the tape will rip leaving any coated pieces under the epoxy forever. So, pay attention to the setup time listed by the epoxy manufacturer.


In both cases, fin alignment was merely eyeballed. There are all sorts of fin alignment methods and jigs for those who want to be precise. Measuring fin tip to fin tip after the fact indicated that my eyes remain fairly well calibrated. Next we'll see how much of a mess we can make using chop sticks to apply epoxy filets inside between the motor mount and booster tube. Its a wee little space.

Question: Is there an optimum width of a filet for strength before it becomes a weight/drag penalty?