Monday, May 25, 2015

Tacmod 3.1 FCG Microswitches, finished paint

Here is where I left everything:

The switches came in the mail. Ordered from Digi-Key.

All are Omron.

For the trigger and cycle control, the SS-10GL. This is a common submini switch with a flat lever actuator. 10.1A rated

The rev switch is a V-214-1C6 and is rated for 21A. I have never been a fan of submini rev switches, in my opinion they are a cut corner.

Now that microswitch ratings have come up, I figure I will post this excerpt from the datasheet of this switch:

Note how the DC current ratings work; at low voltages there is no derating from the AC rating. You may have encountered the very low DC ratings and wondered about switch life in our applications, well not to worry.

Also note the motor load ratings, which are continuous current, with footnote 4 specifying an inrush current of 6 times that.

Typical 180 flywheel setups will thus fall into this switch's ratings which are for a life of minimum 100,000 cycles. Assuming you rev every shot individually, getting a hundred thousand rounds out of a gun without anything breaking or becoming obsolete is unheard of.

Similarly, the inrush ratings here allow for 180 stall current with this particular switch. Now, most of us aren't using the V21, we are using something more like the V11, but even that is a lot less over the switch ratings than some people have thought.

Finally, everything else is ready for wiring and an inner barrel.

I had a few issues with painting that player number. The stencil I had for it wore out and gave a really shitty result this time, so I masked the lettering off by hand and sprayed red to kill the overspray. That worked, but there are some red leak spots and blemishes if you look too close. I am just not the greatest at paint.

Improved magwell area bodywork is smoother and doesn't have a sharp internal corner on this one. Also, rail install.

Here's where I put that stored energy tag. It is brushed aluminum. Matches the paintjob nicely

Charging handle. It isn't just there to be tacticool, there is no other way to grip this jam door.

Still toploadable even though it is a flat top

To do:
Install arming plug connector Install live center disconnect switch instead of an arming plug
Make cycle control follower
Build FCG
Install charging connector
Shorten a Stampede inner barrel to fit
Add magnetic jam door latch
Figure out the sling situation (Later?)
Tag people.

Saturday, May 23, 2015

Koosh Dart Tacmod Chrono Session - Crazy Results

Check, this, out!

I wanted to give these darts a test based on the significant foam change versus past darts, and I did.

The data will speak for themselves. These are here as images because Google Docs goofed up my graphs. Pay close attention to that Y-axis scale, it is NOT in error!

Remember when I said these darts hit hard? Well, they really DO hit hard. They won't be not calling their hits with these!

Yes, my chrono is set up properly! The setup is identical to what I ran the Kforce test on. Everything else is reading just where I expect it to.

These are the Feb '15 darts with the relatively thinner, weaker foam:

But even they shot a lot hotter than the koosh I have tested in the past, including the early '15 BW12 forest green and the 2014 Yutoys blue.

Neither of these specific batches of darts I had previously subjected to any kind of testing.

My Retal only barely managed to peak at 100fps with either of these darts. I didn't record Retal data because I do not want to wear these darts out, I want to turn that performance on zombies 2 weeks from now!

Friday, May 22, 2015

K'nex K-Force Dart Initial Test

This is the dart introduced by K'nex Brands, LLC along with the new K-Force Build and Blast line.

30-round pack with target, purchased at a TRU in Orlando, Florida in late May 2015.

I will begin by noting that other nerfers have had mixed results. Darts included with other K-Force products and darts sent by K'nex PR have not given anyone trouble, but these casepacks are another story, with accuracy issues and glue problems. I had some of that too.

The big innovation here is the tip design. As the market fills up with patents and customers demand higher performance, toy/stock/superstock dart tips are seeing a lot of new ideas. The Kforce dart's defining feature is this multilayered lattice structure to make an impact-absorbing tip without a hollow air-filled dome.

Like the "koosh" tip, these have been identified by the NIC as a potentially improved tip design, providing both safety and decent mass distribution.

Now onto the darts I received. I had 3 darts in this package with excess protruding glue.

As with the recent koosh order of mine, these are exceedingly difficult to deflash. The tip tends to remove cleanly upon trying.

The tip is thermoplastic elastomer. It is slicker than recent Hasbro dome tips. No magazine feed issues were encountered.

Foam length is about 1mm longer than a typical Hasbro full length dome tip dart (ZS Elite shown). This caused no issues with magfed guns in the test. I have no working revolvers to test, but in some borderline cases, these may have to be trimmed slightly.

L-R: May 2015 Yutoys koosh; Kforce; ZS Elite.

The foam on these is nearly identical to typical Hasbro foam of the last 2 years, including bore size and stiffness.

No barrel issues.

Now, getting to the test shoot.

I am steadily losing generic test guns to configuration changes and arsenal downsizing. Also, I have received negative feedback about sample sizes. Unfortunately, I cannot afford what it takes to be statistically proper about every single test. I cannot afford 50 elites every 2 guns, which are darts I do not want to own after I am done chronographing. For dart testing shoots, I cannot afford to go out and buy 50+ rounds of something new and untested like these.

Taking these pressures into account, I have changed the superstock dart test shoot protocol to preserve maximum player relevance and supply more shots per gun without a cost increase to me. There are now two test gun classes - a superstock magfed flywheel gun, and a superstock Hasbro springer with a stock bolt. These cover all the demands of most primaries. The string length is 20 shots, the number of darts used is 20, and each gun shoots twice in alternation.

This provides 40 shots per platform as well as a rough indication of any rapid aging problems with the darts over the course of 2 flywheel and 2 spring shots each. Since the flywheel and springer critical areas of the dart are at opposite ends of the foam, the effects on the opposite platform apart from handling and loading are minimized.

Chrono session

Here it is the Tacmod 2.1 prototype and the Retaliator Hammer.

The results were interesting. Both platforms dropped velocity and increased in variability in their second run. More worrisome, however, were several garbage flywheel shots after the darts were used.

Note in the Tacmod string, several poorly placed shots that did not trigger the chrono caused me to have to reuse fired darts early (the grey shots in the spreadsheet), and you can see how the velocity went down as soon as they were fired a single time. That is disappointing.

Quick accuracy observations: A small pizza box was placed 30 feet away and shot at 10 times with the TM2.1. This is NOT a human silhouette test or effective range indication, it is only to judge stability by the dispersion at relatively close range.

Kforce (some used): 6 hits.

Feb '15 Yutoys koosh (used): 4 hits.

May '15 Yutoys koosh (some used, most reglued): 6 hits. Hard hits, too.

In all these are another mixed bag at this point. Despite finding quality issues, the accuracy at superstock velocities is not shabby. However, the rapid performance drop is unfortunate, and the dud flywheel shots potentially a killer flaw of this tip design.

As is usual, I will field these and report on their viability.

Wednesday, May 20, 2015

Current Koosh Observations - Yutoys May 2015

My latest (early May) Yutoys order arrived. Let me be honest here, it was a mixed bag. In the end, I am still satisfied, and I will get to why, but first, the problems.

To begin with, rather than the cardboard box usually used, I received darts in an envelope. The result was 13 smashed foams and a greater degree of bend and deformity on average. That isn't good.

On opening up my envelope of darts, I was disappointed to find that darts from Yutoys are now also coming with a huge amount of excess dried glue around the tips. Apparently now, in typical Yutoys lagging fashion, Yutoys has received the same latest stock that BW12 has been selling, which is notorious for this messy glue. Except on these darts, the problems are worse than ever and new ones have materialized.

Note those two tips on the left. They are not seated on the foam. The three on the right have monumental amounts of glue sticking out. Completely unusable amounts of glue.

More unfortunate, is that the excess glue on these, with the poor tip seating leading to a thicker glue film, is very difficult to remove without removing the whole tip. Once you start pulling at the flash, the whole thing unzips and falls off. So, I had to disassemble and reglue the vast majority of this case of darts.

This is what I got after going through 4 clips of these. All removed tips on the bottom ready for bonding, usable darts on the top. These were the best 4 clips, too.

The other big change, which is almost entirely good news to me, is that the foam on these is much different from what I received in the past. It is larger bore, thicker wall, with a smaller center hole, higher density. Very similar to the foam on the original Voberry darts from the Amazon era. And that is probably the most awesome foam to ever come on a superstock dart.

Barrel fits are tighter, of course, but it works with stock .50 cal barrels. I tried some in a Triad and the Hammer pump (which I am unfortunately selling, that gun had a real good run and I will miss her). The Tacmod of course did great with them.

Preliminary accuracy observations are solid. These seem to be beating out the old Yutoys blue that came with properly wiped glue.

The larger foam OD helps keep the tips away from the mags and inner barrels, and the smaller ID fits very tightly on the tips, so they have all been perfectly centered (which is never the case with the mid 2014 era koosh).

That tighter fit is probably why there are all these non-seated tips, though. It seems they just continued blindly into the new batch of foam without making any effort to calibrate the machines to make good darts out of it. Not to mention the glue wiping (or lack thereof) issue. Come on, UBS, I know you can do better than this.

Well, after a long fatiguing session of gluing darts, I now have a case of something really, really nice. With this foam and the bulletproof RM-process tip bonding, the only thing that could possibly make these darts any closer to the ultimate form of the koosh dart would be the old school slick vinyl tips. So I'm not complaining. I wouldn't mind getting another case exactly like this one in the future.

What I have to worry about, though, is that the koosh dart is steadily losing its OOTB usability to these quality problems with the assembly. I heard Cooper mention something about koosh troubles in a recent video and I figure it must be related. Myself I really don't care if the koosh is basically a DIY dart kit, because if the foam is good and it is glued properly, it is still an amazing superstock dart - but the hobby as a whole needs accessible buy-and-shoot options and the koosh has been filling those shoes (however well or poorly) all this time, becoming part of the foundations of the superstock revolution.

The trouble posts are coming, and so might be the rise of the USC dart. Perhaps increased FVJ and Voberry usage, with a hint of Kforce...

Speaking of those, I will have the test shoot up for the Kforce probably tomorrow. And for these too, since they are in my book a whole new dart.

Monday, May 18, 2015

Tacmod 3.1 - All Downhill From Here

A while back I modded a RS stock for this to accept a battery. When I had it mostly together, I couldn't resist a mockup. Note the super tacticool Mega dart muzzle device.

The build stayed stalled while I was away from the workshop, and more importantly my heat gun, stash of PVC, paints, and battery welder.

Within the last few days I got back to those things, and it progressed very far, very suddenly.

XP180s installed in a Stryfe cage and receiver hacked. I finally just bought a Stryfe to get that cage. Was a much easier motor install and hopefully the spring feed guides work out too.

Did all the cage/magwell area fabrication and now it's starting to look like a Tacmod. Also, I filled in the recess from the old side rail with a PVC panel. It is now flush and will make a solid place to bolt on one end of a section of picatinny in the future. Finally, it now has a big-ass flash hider.

Thursday, May 14, 2015

Demolisher Flywheel Cage: Interesting.

In my Tacmod 3.1 build I have come to the point where I need a flywheel cage before I can go much farther. The Tacmod cage is modified from the standard configuration and the bodywork is built around it.

Given that I have a Demolisher currently waiting to be turned into something experimental, I decided to check out what sort of parts were in there.

A few observations going in:

Cage geometry (see - the flywheel definitely looked deeper than a regular Nerf flywheel, and the cage wider. It is also noted that the gap has been decreased, and the flywheel diameter is not why, that's all in the cage.

Performance: All the following are data from FDS using the same chrono, procedure, etc. Demolisher, FK180SH-3240, 2S lipo; RapidPistol, FK180SH-3240, 2S lipo; Stryfe, FK180SH-3240, 2S lipo.

Now consider this, the Demolisher has the longest inner barrel of any of those. Yet it shot the hottest, with identical motor speed and torque curves.

So something's up. Whether it is the gap, the coefficient of friction (see below), the inertia (see below), something's not so ordinary about our nerfy Little Friend in construction orange.

So here is what I found:

Demo on the left, RS on the right! Note the two are aligned on the barrel axis!

The Demo flywheel is MUCH deeper. It does NOT align on the bore axis, it sits to the side and the dart contact is close to the non-hub edge in the stock installation.

The motor mount socket is deeper and the motor sits farther inboard.

The flywheel is a different material. It seems to be ABS or a similar styrenic - not the familiar Delrin.

Here you can see the two cages lined up snout to snout, showing the mounting ears aligned. Note that the motor side is nearly identical in terms of where the wall of the cage is, but the cover side is pushed out quite a bit to accept the taller flywheels on the Demo cage.

Compatibility observation: the RS cage in stock configuration has more crap sticking out farther on the cover side than the Demmo cage, regardless. So there should not be a clearance problem with installs of these into the Stryfe/RS.

Here are the cages from the feed side:

Demo (motor side left)
RS (motor side also left)

The stock flywheel installation leaves a LOT of room for the fly to be seated farther on the motor shaft. This is a good thing for FK series Mabuchi users, because the shaft length is not ideal, and this cage allows moving this flywheel closer to the motor for more shaft engagement without affecting what is seen by the dart at all nor having the flywheel dangerously close to anything.

This position is with the entire hub bore engaged on the FA130 shaft. A regular fly in a regular cage would be about centered when installed similarly.

The Demo cage bolts up to the front mount bosses on a RS barrel shroud. The alignment all works.

The lower rear receiver boss also bolts up, but the upper one doesn't and would need to be modified and some webbing trimmed.

But here's the problem:

The Demo flywheels I have fit WAY TOO LOOSE on typical motor shafts. No way I would trust them to stay on.

I have considered sending a flywheel job to a machine shop, get them copied (with slightly larger OD and no taper) in aluminum, and kiss the balance and shaft fit problems goodbye forever, but if I am going to do that, there is no point in using the Demmo cage at all. I can get the same result as a Demmo cage in the Stryfe cage if custom flywheels become involved, and the Stryfe cage bolts up directly without modifying the receiver of my RS.

Since the flywheels aren't Delrin, I could use an old trick, and use some superglue down the bore to tighten them up. Hell, I could even sand my shafts and glue the flies the hell on. But do I trust that? It gives me the heebie jeebies to be running around with that sort of hack thing done in HvZ, with XP180s that will have shocking torque trying to bust apart anything in that bore area. Delrin and proper fit would give me peace of mind that a few FPS are not worth. Plus I want to try the Stryfe feed guides still.

So back to the hunt for a cheap Stryfe to perfect the TM3.1.

I figured I would post this anyway as it may be useful information.

Shelf Watch 05-14-15: K'nex K-Force at Millenia TRU

Finally found em!

Mega Boom

Dual Cross
30 darts and target
Of course, I bought darts. Those will be reviewed when I have access to my chrono and Tacmod. Initial results are promising, but not groundbreaking, and I may be having the same quality problems (including excess glue) as some other nerfers who have tried these already.
Also saw this Zing bow knockoff. Sorry for all the blurry and badly composed images, I was trying not to look sketchy photographing the shelves.

Wednesday, May 13, 2015

High Velocity BoomCo First Test Shots: Fail

So I got back to Site B and commenced the initial tests of the slick-coated BoomCo darts.

First of all, the barrel stock:

K&S 9319 - 1/2 OD x 0.035 wall aluminum tubing, .430 bore.

Perfect for use with the BoomCo dart and a pneumatic engine. Slightly smaller bore than the .436 provided by 15/32x0.014 (thin wall brass and aluminum). You can just see the slightest daylight around the widest part of the dart which is where the body is roll-crimped onto the tip.

This stuff is also a lot nicer to work with than the thin wall tubing. It is a lot like the .527x5/8" stuff used for .50 cal, just smaller.

I picked up a 3 foot stick of it, which I did not modify - because I now plan to return it.

This is the test gun, a PVC "mini spudgun" with a 150cm^3 chamber and a 1/2" port piston valve. The valve performance is excellent, similar to a QEV. This thing is more than equal to any sane use of a 4B tank even at sub-50psi pressures.

I didn't bother with the pressure gauge yet. Or the chrono, because I was an idiot and left it at Site A. However, I varied the pressure and velocity quite a bit during the test. I never went beyond about 40psi (12 strokes of the hand pump that I used).

Here is a sample of what I shot.

The shortened darts had the rolled-in end restored with a lighter.