Friday, September 23, 2016

Rivaloader Improvements, Combat Test, USF HvZ TM Footage and HIR Format Thoughts

Now that the basic design principle of the Rivaloader is established and proven, I have moved on to the initial refinements.

First change was to increase the impeller speed, at this stage by sticking a faster 380 motor from an old blower on the same gearbox. That pepped it up a bit. Second was this:

The angled feedneck is a preliminary shot at matching the exit path of balls more closely to the velocity they are being given in the raceway, reducing the tendency to bounce over the feedneck in the original.

The setup with this tall prototype assembly ends up making my current vertical feed gun way too awkward for combat, so I shot the V1 with the faster motor installed at this past Sunday's game. However, there was a slight improvement with this configuration to what I would call "nearly acceptable". I am going to reach for more and more extreme versions of this design that make the feedneck intersect closer and closer to tangentially with the raceway.

What idea this sparked is that if the anti-jam (rollover tolerant) clearance is maintained at the tightest pinchpoint in the system, any raceway design can be used. So this may get away from a flat sheet baseplate in the next iteration and instead have a descending feed path starting at, say, 0.75" from the impeller blade underside and then spiralling down and off at a low angle.

Other major targets for improvement are the gearboxes (I found something taller ratio and stronger for the V2) and the impeller blade count and profile which is currently the original crude 2 blade unit. And of course it needs a nice gigantic hopper, once the engine is squared away. Multiple cases of red and white Cornucopia V2 and paintball pods for reloading are on the way.

Pre-game I fabbed up a lid for my hopper:

This is the configuration I used: V1 Rivaloader body and impeller with faster motor, 60 round hopper, new lid. Stock Zeus cage and motor set and same old powerfeed from before, and a 1300mAh 3S Monolith. Getting around 13rps in this form and nominal velocity.

I won't bother with posting the shooting video of the setup because videos of shooting at nothing are boring. Instead, let's just see the combat footage, which leads me to my next subject. USF HvZ training mission footage is up on the youtube. Check out the playlist for the entire event, but here is most of the relevant shooty stuff in this one.

The development gun ran like clockwork and shredded zombies without a single issue. Outofdarts, I don't know why you are jamming, I still haven't had any malfunctions with this system. Well, aside from me shooting out my hopup...

David Kaye saw that it was torn almost completely through at the game. I got home, railed on it with what was left in the hopper and the tip of the nub went flying out the barrel. Whoops!

Classic fatigue failure, strange seeing it on rubber like that

I may very well have had less range and accuracy that I should have from shooting through the broken nub all day. Oh well, I will slam a new inner barrel assembly in there today. I will use the old one to experiment with more durable aftermarket hop nubs because this may just be what happens when these things get run this hard and rack up so many rounds, this is a cheap part that comes in a fuckin toy after all. Fiber reinforced belting should do it, maybe a piece of a timing belt or flat belt. May also try making the hop adjustable.

Now, some observations about the HIR format.

Don't steal my HIRs
So by now you have probably heard a ton of discussions about HIR. Sectional density, slow floating shots, dodgability, hopup dependence, being outranged by .50 cal opponents, plenty of noobs not understanding physics and thinking they can shoot them hundreds of feet at 400fps with a giant airgun, people who switch completely to them and extol their virtues, people who think they are crap...

I will say I really like them.

Are they ballistically the most optimal or competitive projectile within superstock safety caps? Hell no. .50 cal just stomps the crap out of them in terms of retained velocity hands down and with modern .50 cal hardware shooting those darts, HIR is flat outclassed with nothing to be done short of a significant mass increase (which hinges on the manufacturers to tool up and produce it, and the process to be able to make usable ammo at a higher mass). There is no debating that. Accuracy has been a HIR selling point, but Gen3 koosh is comparable and hits a lot harder and faster at range.

Furthermore, the other major problem with HIR relates to the design of practical primaries for the practical player. The .90 caliber ball is a very awkward dimension and just does not lend itself to magazine feed. The original Hasbro single-column mags from the 2015 line did not provide the desired 15-20 round minimum capacity and yet were very long. I applaud Hasbro for tackling this problem and arriving at the multiple-feed 40 round Khaos magazine, but these are the size of a textbook, and as of right now, the mags are still not available aside from the single mag that comes with the gun. Hence, the Khaos is nearly a moot point pending the solution of this issue.

HIR does NOT get along with bolts/breeches of any kind. Frankly, HIR guns that are not flywheel are inherently troublesome and inferior, because they always need a way to seal off the breech. By contrast I have never had any kind of stoppage with my old Zeus configurations nor my current hopper loaded unit, and most field issues I see with flywheel HIR guns are stock Zeuses with the crappy, slow-ass semi-auto trigger group. Which has a very weird looking form of bolt, but it is still mechanically a bolt, regardless. No wonder! HIR is practically made for flywheel and continuous-motion feed. It is a strange situation really, and not one friendly to the "I don't like flywheel" crowd at all. It just reinforces the niche, however.

And finally, even at .90", they get lost. HIRs bounce like mad, roll once they land, and will find every hiding place and escape route.

Now for the redeeming qualities:

Extreme durability! Here are some Hasbro HIRs I have been using for testing since the early days:

These have been shot many dozens of times, left out at fields and the yard at Site B and then found months later, stepped on and generally abused and ignored.

They show their history and some have serious surface wear, but they still feed fine and shoot great. The polyurethane foam is much more resilient than PE dart foam and due to both the material and the launcher design associated with ball ammo, there is MUCH less impact on performance as it wears and weathers than there is with PE foamed cylindrical darts. I lost track of how many times I have got into the subject of dart maintenance on reddit, but the gist of it is that for community groups and commercial fields that rent or otherwise supply .50 cal darts and/or gear, a concerted effort and constant expenditure is necessary to avoid giving players a terrible experience with crappy deteriorated ammo causing poor accuracy, inconsistency and malfunctions. This does not mean that .50 cal cannot be made to work, but in that type service, HIR and its durability and benign failure can be a huge benefit. While HIR cost is still around double that of a quality brand of .50 cal dart, HIRs in field/community pool use could last well over twice as long, and in sealed environments like indoor fields where ammo cannot escape, it makes a lot of sense. HIR is very carefree. Step on it, grab it from the ground and shoot it without worry.

HIR is great for bulk loaders, great for support and all-out OTT spam loadouts (compare to the gravity stickfeed Nitron and belt-fed .50 foam), great for abstract "sporting" hardware with no pretense of being the slightest bit milsim, and great for playing "sportlike" games. It is also inherently very safe and difficult to alter or cheat with, being that the entire projectile is made uniformly of one piece of molded foam. It will never replace .50 cal for me but I think it has a definite future. I am going to keep using it for sure.

Thursday, August 11, 2016

The Rival Revival: HIR Powered Hopper Development History.

Some of you remember this project of mine:

Oh man, where do I even begin... This was actively being developed about a year ago. I only recently happened across a cheap Zeus and bagged it and its cage, complete with flywheels and stock 360 motors, to replace the problematic parts in this from past experiments without spending much on it; and thus, I unfroze this thing.

At the time, Nerf Rival and its pioneering .90 caliber foamball format was very new, and the one question on everyone's mind involved hoppers and high-capacity bulk loading systems which the new spherical ammo begged for.

Airfeed, as popularized by outofdarts, Radiosilence187 and the "HIRricane" lineage, had not been invented/discovered yet. The focus was traditional paintball-style hoppers. Some prior art:
  • Reddit user woodpiece converted a Zeus to fire .68 caliber Reballs (rubber reusable paintballs) using a gravity paintball hopper, a sweep pipe connecting the feedneck to the breech, and a powerfeed device made from half a Hasbro .50 cal flywheel cage.
  • Mr. BadWrench (Donald Wester on Facebrick) attached a gravity hopper made from a plastic container or funnel to a semi-auto Zeus.
Nothing however existed which handled HIRs, supported reasonable ROF, and fed automatically without shaking. That is where I started, determined on whipping this problem real good. I wanted to break that barrier and make powered hoppers work. It didn't have to be ideal on the first go-round - it just had to work, and rip, and not jam; and the absolute nature of the last point cannot be overstated. I hit up the surplus vendor for some likely parts, grabbed my heat gun, dremel, PVC pile and Devcon, and got to it.

Wednesday, August 3, 2016

Mailbag: Artifact "Red" (Parallel Axis) Milled Flywheel Cage

Recently there has been some buzz about Artifact's new superstock flywheel products and I have been super excited to see what's up with this low cost, high quality stuff. This was the first of the line to show up in a listing, so it was my first order to arrive.

Motors NOT included.

I used BuyChina here and this was the timeframe:
Order placed July 5.
Shipped July 13.
Arrived July 25.

Fairly good, really. I recently placed another order which contains sets of all three models of Artifact flywheels and one of the canted axis (Super-E, the gold anodized one) cage to complete what I need to put the Artifact cage and flywheel products through their paces.

These cages are CNC machined aluminum, much like the DRS Performance product you probably know about. They are one-piece and mount motors with screws as with all other hobby market cages.

The two cages available now are superstock standard, and intended to fit all Stryfe/Rapidstrike cage applications.

Here I have installed a pair of Banshee-130. I didn't happen to use the motor screws that come with the cage, I had some on hand that came with XP180 motors. The stock ones may be too short for certain motor cans such as the MTB Hellcat.

Test fitting in a Stryfe receiver.

One observation here is that the mounting bosses don't locate the cage with all that much precision, there is some play. Other cages fit the bosses like dowel pins and that sets the alignment. We will see what happens with that shortly. One positive of the clearance is that the cause of alignment issues is often the receiver being itself out of tolerance being that it's usually a crappy toy part. We can use that clearance to adjust and shim out problems. However, I am concerned about the potential to NEED shims or adjustment of every build even with a known good receiver and furthermore the potential for a drop or hard hit to knock the alignment out.

Inner barrel length required for these will be different (longer) from a Hasbro cage if you are switching from one of those. You will have to replace your old inner barrel with a new longer one. There is a counterbore about 1/8" deep at the front of the cage to locate the inner barrel.

These parallel axis cages accept standard-design flywheels, such as common Hasbro cylindricals, Workers, BlasterParts, and Artifact's own. This is unlike the DRS Performance cages which use a different center distance and smaller pitch diameter deep-concave flywheels in order to fit the flywheel rims within the standard cage envelope.

However, the Super-E cages are reputed to not accept certain flywheels, notably Artifact's standard flywheels which are of a mild-concave design. This is likely just a clearance issue. Artifact has specific flywheels for that cage, which are one of those I have on order (they appear to be a more heavily truncated version of the same mild-concave design). Worker flywheels are said to fit both Artifact cage models.

The inside surface of the mount sockets is around 0.5mm farther inward toward the access side versus a Hasbro cage. No caliper so I can't get at the mount socket depth or relative motor position, but I suspect the motor is pulled slightly farther inward here and this is likely why Artifact flywheels have zero hub protrusion on the inside unlike most other designs. A bit more clearance for the bearing housing there.

Now this is one of the more interesting bits of the design. The "red" cage, at least, takes a very laissez-faire approach to round control. That bore you see is the same diameter as an inner barrel! Even a Hasbro cage has tighter guide rails, although it does not present a parallel guide profile prior to and during flywheel contact, and this design does (much like other tubular guide systems and like my main Tacmod's prototype guide rail system).

We will see what happens with this concept when I test it, first with cylindrical flywheels and then with Artifact's concaves. Conventional wisdom is that the lack of round positioning will cause havoc with concave systems, but no flywheel profile like Artifact's has been extensively tested yet; the best parallel to them is the BlasterParts flywheel, which has unsatisfactory crush and doesn't make much velocity but otherwise is acceptable and consistent on Hasbro cages.

You can also see the feed ramp in here which is just a nice big chamfer. Simple, should do well enough.

FK130PH-2460 Motor Failure

A quick tech observation post: This -2460 was one of the pair driving the flywheels in our scout's pistol Stryfe during NvZ'16. It had previously given reliable service through several games. Coming into the final mission briefing, the user discovered a malfunction with a dart left between the flywheels, cleared it, and then found the dead motor. The Vulture in my backpack was promptly issued.

On gun teardown the offending motor was found to turn freely and smell of burnt magnet wire. The motor was then removed and disassembled and the cause was found to be a winding burnout as expected. You can see melted varnish on 2 poles.

Commutator, brushes, and winding terminations were all intact and the windings had not structurally failed.

The battery at the time of failure was a 2S 1600mAh Monolith.

User was questioned as to what immediately preceded failure and noted that he had been running to a safezone and then noticed that his flywheels were locked up. I could not get a clear idea of how long the motor may have been stalled. It is possible that this is simply a sustained stall failure from a malfunction followed by accidental activation while running, but also possible that the only stall occurred when the problem was discovered and the failure had been ongoing up to that point.

Based on what happened here, the bright (clear varnish) color of the undamaged wire, and the failure mode (melting at what must be a low temperature from the lack of carbonization, compare to the appearance of other high quality motors' burnouts, example being the Mabuchi -3240) I have my suspicions that these cheap motors are wound with wire of insufficient insulation temperature class and are vulnerable to thermal damage from momentary stalls and/or sustained hard use.

I am planning to preemptively take these out of the remaining Tacmod in the squad that is equipped with them as soon as the chance presents itself to do so. Suspicions like that are not worth playing with.

Tuesday, July 19, 2016

Gameplay Footage: USF/Tampa Bay Nerf Club HvZ Day Game 07-16-16

Videos are up on The Dart Zone Youtube channel.

Background on this game: The mod team for this event had it all planned out, and then a TON of people who registered didn't fucking show up. Thus it was HvZ with something like 17 players. You know that won't be what even 25 or 30 players will be like. Also, the mods had to change everything on the fly, so keep that in mind. The mods did a good job. So while there may be little action especially in that first mission video (which I will just leave for you to go to the channel and see if you want to along with the mission briefing for this one), consider it a good camera test.

Lore information: The scenario in the original planned game is that locals find areas of land with toxic chemicals seeping out of the ground (a lot like the Love Canal disaster in which a town was built over an undisclosed hazmat landfill) and strange occurrences nearby, including zombie-like creatures. We the humans are there to investigate.

After lunch, we lost even more players (If you were one of those, shame on you, you ARE the reason games occasionally end up in this sort of jam and aren't as big or fun). With HvZ off the board we ...kinda halfheartedly played King of the Hill. I was sure not on my A game by this point. At least there is some on camera Tacmod and WASP action in here:

The Mobius really made the grade. It takes GREAT video, the battery lasted through multiple missions (I charged it in the field during lunch with my Miller ML102 and some 18650 cells, I didn't try to stretch it past 3 missions) and at 848x480, which is MUCH MUCH sharper than the compressed shitty youtube FLVs, it is really easy on storage at around 4.25GB for 80 minutes of clips, while also being capable of 1080P if I wanted to do that. It didn't glitch or shut down in the blazing heat that day and the hat rig is great... for video at least, it is in the perfect place. Not too low so all you see is the gun/sight, not too high like a gopro head strap so you can't figure out what I am shooting at. The one annoying flaw is that being on the underside of my hat brim the mic is way too close to my face and gets breathing making me sound like an asthmatic. Gonna have to try solutions for that.

NvZ'16 Dart Observations

At the past Nation vs. Zombies, arguably the 800 pound gorilla of the big games with all the high level players in North America attending, most every modern dart in use was being fired (and sold). Koosh really proved itself with Gen3 by the pallet load. I also got to test the most recent production of a few darts known in the SSC as offenders...

ACC (ACCurate)

I picked only one of these up from the field. No news to report on the factory dart (it caused the expected annoying squib when I stuck it in my Tacmod) but I do have something to report as to the cause of the notorious flywheel incompatibility: It is simply the tip glue. My factory dart was assembled with CA glue on the tip core ONLY and while the tip wanted to stay on, the super elastic compound let it stretch and bend and flop around on the front of the dart.

I refoamed it with a new foam shown in the image and glued the tip properly (by the surface, not the core) and it now shoots fine from flywheels.


These solid ogive things were constantly around Thunderdome. I saved two from the NvZ dart pile for documentation.

I was putting these through my pistol at Thunderdome and they did perfectly fine. Tacmod doesn't mind them either.

Compared to a classic flat dome FVJ:

And to its less painful competitor, the ACC tip.

Yes, these are sharp and hard and not friendly. I wouldn't want them marauding around the field unless eyepro was mandated and bystanders not a factor. The ACC (which is the same tip as used on Artifact short darts) by contrast is VERY cushy and safe.


These were in the minority compared to koosh but I still came home with around a dozen. The "Little Valentine" is a distributor, they also have Gen2 Voberry with the same printing and sell on Amazon. Nice advertising plan, put your brand on your darts which get shot everywhere leaving everyone wondering and googling.

Anyway, these are reportedly awful for flywheel apps: (1) the tips cause malfunctions, and (2) some have overly short foam and FTF. Neither problem is apparent with these, they have correct length foam for a full length dart and have never jammed my Tacmod. They are also accurate as hell! It's seriously impressive. Unfortunately they still have crappy velocity retention and crazy drop, so it's like a weak sagging laser beam. I prefer aiming and I do not lob shots, so they are still a big nope for me.

These tips are plasticized PVC. They are slick, like Voberry, Gen1 koosh and old school chinawhite tips, and feed great. The suction cups overhang the nominal caliber considerably which is weird but seem to flex enough to avoid "rimlock" no matter how you load them.

They would be GREAT darts in an indoor CQB situation being cheap, reliable and dead nuts accurate.

But what about velocity?

Seriously, these darts are all used and beat up, I only have one of one and two of the other, and it could be misleading. Generally the FVN did what I expected from FVJ darts, the ACC was a bit down on velocity as well, and the USC seemed to be close-ish to what Elite does from the same setups. All speaking of flywheel... master race that is.

Sock Grenades For The Modern Era

WHAT? A post about socks? From the most hardline of the Gun People in HvZ?

Yes. Socks! No matter what, even if I "know I won't use them", I always have them in case I am wrong, and you should too. That matter is worsened by the modern trend toward using socks as the alternate ammo of choice for stunning partially-invulnerable special zombies. But as everything else escalates, socks need a bit of attention.

Some of the problems originally experienced with socks were that the result did not have any durability and was far too soft and low-density to throw effectively. Thus, players began using more engineered rolling techniques and tape by the late dark ages (2010). Carrying socks was troublesome, so velcro was often added. That is where the mainstream of sock technology is left, with these main troubles:
  • The hook and loop system (Velcro) may detach from the sock when it is ripped off the carrying gear, whether it is PSA backed peel/stick type or is glued on with a separate adhesive.
  • The typical flat rolling method creates a tendency for the inside end of the sock to work its way out the axis of the roll and then the whole thing unravels.
So this is how I do mine, which is based on work by one of the UF sock gods.

You need:

  • Scissors.
  • Medium size men's ankle socks (work best, use your brain for alternatives)
  • Duct tape
  • Adhesive back hook and loop fastener (Velcro), loop side (*)

The first step is to lay out your sock as if it came out of the package and cut it lengthwise in half.

Now prep your tape so it is handy because you WILL NOT have free hands in the next 2 steps. All strips should be around 10" long. You need one 1-1.25" wide strip and a number of 1/4" to 1/2" strips.


Start at the elastic end of the sock strip and start tightly rolling. The more tension during this process, the denser the result. Note that you leave the sock strip folded as it was after cutting.


When you complete the roll, hold it with one hand and grab the 1-1.25" tape strip with the other. Tightly tape the roll in the same direction of winding as the sock strip. 

Your sock roll is now a bit sloppy and uneven at the ends. We can get cleaner results and better compaction. Use a somewhat blunt stabby instrument such as the tip of your scissors or a letter opener to repeatedly poke the protruding material into the center of the sock roll until it is flat. It will act like a sewing needle and carry the fabric with it. CAUTION: Don't stab yourself in the hand while doing this!

Repeat on both ends. This is the result:

Finish it by placing against a solid object (not the carpet shown) and hammering with anything convenient until you have a dense, flat-ended cylinder.

This is what you want a sock to look like.

Now grab one of your narrow tape strips and wrap, tightly, in the orthogonal direction to the winding as shown.

This secures the ends of the roll, preventing end unravelling and loss of compaction.

Cut adhesive backed Velcro to approximately the size shown - about as wide as the diameter of the sock and slightly shorter than the width of the rolling tape strip.


Now this is the key.

Grab another narrow tape strip and wrap tightly near the end of the roll, overlapping the end of the Velcro. You don't need much overlap (it is lost surface area of fastener, so try to minimize it).

Repeat on the other end and you have a finished sock grenade.

The Velcro is secured by the tape at the corners, which are where peeling starts, and will rarely if ever fail no matter how frantically you rip socks off your gear as specials come barreling at you.

Now you just need sock gear of your choice.


This guide assumes the following:
  • Your game does not prohibit using less than a whole as-manufactured sock. In that case, choose smaller socks or adapt to a larger end product.
  • Your game does not prohibit tape on socks. In that case, you are SOL.
  • (*) You follow the common HvZ standard of using loop side "soft" velcro on socks and having dedicated sock gear with hook-side "scratchy" velcro, which is the inverse of the normal standard for LBE velcro use, in order to not throw hook side velcro at people. If you put socks on standard gear hook/loop areas, check that your game does not ban hook velcro on socks, because some do.