BTC Chimera ~Review

[a_flea]

Well, I have been waiting for version 3 compatible trigger board controlled MOSFET to come out for a while; and when they did I threw my money at the importer and waited eagerly...

It arrived on Thursday, and today I decided to fit it to one of my V3 boxes, but first a little look at the beast:

The box, strong and compact- reassuring!


The contents; you can see the MOSFET control unit itself, an anti-static packet with the trigger board in, two sets of data wires (a double and triple in each set, they are identical in length so one set is purely spare, nice!), a pair of motor wires (one neg and one pos, both with gold female spade connectors), two different battery cables (one with a Deans connector and one with a Tamiya connector (the latter a token gesture really), and of course some instructions which at first glance seem very well laid out and easy to follow...


The control unit consists of two boards that fit back to back and are wrapped into a neat little package measuring 49mmX14mmX14mm...


Manufacturing quality is great...



The battery and motor cables are connected via screw terminals, the data cables are via miniature shrouded headers (just like an ASCU)...



Soldering is tidy and everything feels neat and solid, battery and motor connection cables are 16AWG and are coated in really tough insulation, they are also pre-stripped ready for fitting, nice! (although I will be trimming them to fit)...



The trigger board has two parts that are 'as one' when you receive it, you must snap the board in two and push the two pieces together to make the complete trigger board up (the out of focus board is the second piece that is initially attached to the main board). You can see here two of the three switches, one for the trigger (silver) and one for the cutoff lever (black). Also notice the data sockets for the data cables...


The rear of the trigger board is very simple with only the third switch on it, this is the selector switch and is operated by a modified selector plate.

So far, this system seems very well thought out and will be much more accessible than the ASCU due to the reduced size and greater gearbox coverage (V2 and V3 so far, more on their way). It is also better made than the ASCU with higher quality materials and components, so I am very pleased with it! Now I just need to fit it!

End of Part One

- - - Updated - - -

Part Two

So, the initial plan was to fit this to my FAL as it has always had switch/selector/cutoff lever problems and I thought this would be a great solution; but when I looked at the destructions, the only diagrams for selector plate modification were for AK's and G36's... No problem I thought, I will use my awesome abilities to judge the SIG selector modification by looking at and measuring an AK selector plate!


Alas, as you can see in this image, the Chimera requires a full length selector plate which my FAL does not have, and the availability of SIG selector plates is pretty dire. So there is currently little hope of fitting a Chimera to my FAL...


So I decided to fit the Chimera to my AKs74UN instead which up til now has been running a GATE3.2 MOSFET which has been very good, but in all honesty was just a stopgap until a V3 trigger board MOSFET was released... Yesterday however, before I even got a chance to use my AK at GZW the piston stripped! So I have ordered a new one, but until it arrives I cannot complete the installation...




Fitted in place of the switch, as you can see the top corner of the board needed rubbing down to fit in without forcing it (as a note, installations into Ultimate and Lonex V3 boxes will probably all need this doing)...



The board sits flat to the side of the gearbox shell, if the cutoff lever isn't perfectly flush with the shell or recessed it may rub the board meaning that it will hold the cutoff switch 'on', however with such a snug fit it is easy to prize the board up a little and position it so as to relieve the friction on the lever. I doubt this will rear its head again as it feels pretty firmly in-place...


The modifications that need doing are very simple, first is the removal of a segment of the selector plate. As previously mentioned the Chimera requires a full length selector plate so here is the modified plate pictured next to an unmodified short plate for reference. As I had left my scalpel at uni, and my Dremel had died years ago, the procedure was performed with a pair of medium kitchen scissors and a 1.25" flat file- a testament to the ease with which the plate can be modified.


Next, a tab needs to be trimmed off the tappet plate, again I used a file for this, nice and easy...


Fitting the tappet plate required me to attach to spring 'upside down' in order to prevent it rasping on the data sockets. It may be my spring that twists to the left slightly, I'm not sure, but it was only a minor adjustment and should make no difference to the operation of the box...



With the selector plate fitted, you can see the operation of the selector switch. Its nice and smooth and looks to be (by the location of the stop and ramp for the cutoff lever) in the perfect position. Note the missing bit of selector plate would have damaged the switch (pulled it the wrong way) upon removal of the plate.




Here you can see the trigger operate the trigger switch, the switch is operated by the shoulder of the trigger lever link, this allows almost full travel of the trigger and relies on the trigger's spring for resistance and return. When pulling the trigger it feels just like a normal V3 gearbox not short and 'clicky'/'buttony' like an ASCU which is for me, one of its real plus points so far; in addition you can't hear the mechanism either so there is no click or grind when pulling the trigger.




So, that's as far as I've got. As soon as my new piston arrives I can carry on with the installation but for now, I'm afraid, it's...

End of part two

[sparrowhawk]

Re: BTC Chimera ~Review~

ive had a v3 trigger switch for a few weeks now,so i can swap between v2 n v3,but it came with no instructions and your selector plate picture helps a lot

[a_flea]

Re: BTC Chimera ~Review

Part three

Right, received a Prommy piston and soft hop rubber this morning and went about getting them fitted...

Whacked the gearbox back together and plugged in the data cables, I noticed the cables and the plugs are made of better materials than my ASCUV2 ones, its nice to be able to plug/unplug the data cables without opening the gearbox.



Tucked in all my cables...



And routed them through to the foregrip, I am putting the control unit in the foregrip so that I can use all the space above the gearbox for a battery. I normally use a 7.4v LiPo that fits down my gas tube, but I also have a LiFe battery for my SD6, and an 11.1v LiPo as well- wouldn't mind being able to use all three!



I need to get some insulation tape (or black maskers) round the data cables in the foregrip as they show up when you peer through the holes...


Minimal space taken up by the Chimera means I can use all my batteries!!! Pictured here with the 7.4v LiPo...


All done!!!!


And here is a quick video of the trigger response, before it was a standard V3 crankover, pretty basic, nothing to shout about... Now however, it's a different gun!!!! So pleased, great value for money and would definitely buy over the ASCU VII I have- I feel confident that I wont have any problems with this bad boy.

(1080p available on Youtube)


Cheers guys,

A_Flea

[Northernairsofter]

Re: BTC Chimera ~Review

Im making a wee mini review of the MKII Chimera for my you tube , is it alright if i use the picture of the box that you have > as its different to mine and i want the viewer to see the difference..
thanks!

[a_flea]

Re: BTC Chimera ~Review

Yeah no worries!