Tuesday, April 21, 2015

Tacmod 3.1 Progress

Here is what has happened:

Cut up and flattened a whole lot of PVC

Built up the receiver for the flat top. You will see why I laminated 2 sheets shortly.

Seen from inside.

Mocked up rail install.

Flywheel clearance. In the stock RS, the cage is strategically positioned right under the front support for the carry handle. This allows the cage to stick up into the support, without messing up the clean lines of the top of the receiver. Of course, I want to lose the carry handle here, so that is a problem.

I could have left part of the carry handle support intact, but I decided this route with exposing the cage and cutting out clearance in the buildup would be cleanest. I hate those telltale bulges ruining the lines of flat top jobs on these things.

Marking ejection port on the left panel.

Port area cut out on the left panel.

You will see how the rest of everything comes together. I need to be able to topload, since I do scavenge on occasion. Thus the decision to put the port on the left.

Right panel underside with a nice smooth chamfer cut into it to match. You can also see hardware clearance holes for the rail install.

Rail installed with all fasteners. The rail is bolted with 10-24 button allen screws, washers and nylock nuts to a single non-clamshell PVC plate. This is then screwed to the receiver (into the PVC laminates) with 8 6-32 allen flatheads, countersunk. All black hardware.

The underbarrel rail follows a similar pattern. Single layer PVC buildup on the shroud, then a PVC plate with the Magpul rail segment bolted on with its stock hardware.

Mocked up with flashlight mounted:

This thing is SOLID. It already feels great and it isn't even structurally finished. It is also heavy. Heavy is good, nerf guns are too light. I am going to continue on the theme of reinforcing and filling things, especially the stock.

I gave my 552 a try on it. Awesome, as expected.

Not shown, the modified jam door. I fabbed in a charging handle on the side which will allow operating it easily without access to the top, with bonus tacticoolness. I am working on extending the stroke of it as well to make toploading easier.

To do:
Fence magwell
Magwell front
Cage underside bodywork
Fill and finish top rail install
Motor endbell covers
Install arming plug connector
Gut a stock for battery, reinforce and devcon together
Carefully straighten rail installs, adjust the mounting holes and glue the nuts down
Make flash hider
Order switches for FCG
Obtain a Stryfe cage and fly set
Mod cage for Tacmod use
Look into Demolisher Flywheels
Build battery pack
Build FCG
Mod pusher box for 180 motor
Figure out the sling situation (Later?)
Install charging connector
Shorten a Stampede inner barrel to fit
Add magnetic jam door latch
Tag people.

This project has taken on a bit of a SCAR vibe:

It is about time I realized where that cheek rest on the RS comes from. And it is strange that the Tacmod project has gone this direction. I wasn't trying. I was just going for a better superstock rig.

Even before I saw this I was considering adding side rails in their rightful place (up front near the muzzle) too. I think that will definitely happen in the future.

Thursday, April 16, 2015

Tacmod 3.1 Concept and WIP Primary Build

The evolution of the Tacmod lineage:

The concept 3.1 eliminates the carry handle in favor of a full length top rail. This gives a bit more modularity and is a bit more friendly to optics. Additionally, all nonstandard Hasbro rail segments are to be replaced with Picatinny (MIL-STD-1913).

Next car in the Picatinny train will be to develop Picatinny conversions for the carry handle equipped 2.1. The 2.1 is the gun you guys know, the one you have probably been hit by if you play TBNC or Florida Polytechnic HvZ:

Or at least, that is the prototype, which is a work in progress itself. Recently, I finally got around to repairing my charge connector hack once and for all, and with all balance wiring properly separated from the charge current path and a new charge cable made up to match, it charges and balances like a boss.

Wednesday, April 1, 2015

Shelf Watch 04-01-15 Lakeland, FL Big Lots

Something new I am trying out for Shelf Watch, not that this one is breaking news or anything, but I figure that 99% of the time if I or a local wanted something from there I would have bought it before posting anyway. So may as well post a map of where the sightings were:

I went into this Big Lots expecting to maybe find some cheap clearance stuff. Instead, I found 2015 products. Doubledown


It is strange to see such a recent release at this store, but it does appear the Sharpfire, Snapfire and Doubledown (all part of this new shell-less minimalistic design language, all springers based in some way on the Jolt design, and all non-Elite) are aimed at this sort of market. Big Lots, Family Dollar, endcaps at random stores and the like.

The Doubledown actually appears to have a good bit of displacement and feels like it could take a monster spring, and I love the grip frame for aesthetics. The Snapfire on the other hand... Meh. An actual Jolt is just a better way to go than this thing, which is larger and has that cheapo skeletonized grip that just can't possibly feel good. It's like a 99 cent scrub brush handle.

In addition to these, I found some older generation Nerf Super Soakers:

Sadly, no Lightningstorms with the bundled stock. If this had been one of those, I would have snagged it for that price.

And the original generation iPhone rail mount for $6


Nitron Flywheel Motor Postmortem and Observations

So, well over a year ago, I built one local a Nitron. It served well, fired many thousands of rounds without a hint of trouble, and gained a legendary and feared reputation as undodgable full auto Vortex ought to.

Then someone just had to decide that its original 12V NiCd pack was not enough and try a 5S lipo. Okay, I could understand a 3S lipo, that would be almost the same voltage with less IR, less weight and better performance over the life of the charge. I could understand a 4S lipo, even. But, a 5S lipo. Come on, seriously, you guys can tech guns and you know why it was a bad idea.

But end of story, the factory 280 flywheel motor ended up roasted and the RS carbon pusher motor probably on the way out. Now, the pusher motor, who cares, you can just slam any 130 or 180 on there and go, but the flywheel motor...

Just to confirm, it is a generic Mabuchi-type 280. Here it is next to a Sagami "Cyclone" 280

This is going to be the hardest piece of the puzzle. The shaft stickout on the PTO end is 15mm. Most 280 have shorter shafts, 10.4mm and 12mm. Perhaps the 12mm could be made to work? I have not found a single motor with this 2.0x15mm spec for sale yet (except flat can FC-280 which are usually wound too cold to use here as well), it was probably a custom order by Hasbro specifically for this gun. Hell, I'm guessing it was a custom wind as well, see below.

Crispy fride brush gear. These are not EOL and this endbell still has something left but those carbons are about halfway gone. The comm was nuked and jet black with scale/oxide, as well. I suspect why this motor died was the comm.

Armature. I unwound 2 poles which was difficult because the insulation had started melting and the wire was beginning to short and weld together. I counted 112 turns.

This is a good thing, because 280 motors hotter than 112 turns are, almost all of them on the market. The most common wind of stock 280 is -2485 (85t). That should work great for Nitron fly motors assuming the shaft issue can be dealt with.

Custom shafts may come into play here. The comm and armature stack can be pressed off the shaft and a new one fitted. This would be a tedious procedure but perhaps necessary.

I found this interesting. This is the 280 arm next to one out of a FK180. As you can see, there is not a terrible difference here in how much core steel is on these. The 180 arm has a slightly longer stack.

The 280 stack is a bit larger diameter.

The comms are damn near identical. You would think the 280 would be larger, but no. This is probably why the 280 fly motor died as it did, because with 18.5V there would have been arcing going on with that little comm. This is not a 300 series.