Daystate's Air Wolf, Grand Prix and Mk4 rifles all incorporate electronics.
When I first heard about them all I knew was that they work with batteries and that they emit beeping sounds, I was at the time still busy satisfying my curiosity about the Blizzard, Anschutz, S200, S510 and HW100's workings.
One came up for sale and we bought it for Linda after she saw one of our worlds competitors in action with his GP, it's a GP FAC we got her.
Few months later and we now have three of them, two FACs and one dedicated 12fpe GP. Me being a staunch purist did not view the electronic newcomer favourably at first, on hindsight; it was simply because I did not know how and why it worked. I must admit, as a professional photographer I also at first did not think digital electronics had a place in photography, my colour and b&w darkrooms were soon donated to a school and a powerful PC replaced a darkened room full of equipment and poisonous chemicals almost overnight, doubling my productivity and creativity. (= More time to play with air rifles )
Soon after having a closer look the GP I realised that the electronics involved was no more intricate than what's found in automated gate openers. Don't get me wrong, the way old technology and electronic principles were integrated and applied to Daystate's PCP's is brilliant, what I'm saying is that there's no mysterious vulnerable unproven secret microchips, principles or other components involved here, only robust long proven generally used components and electronic principles put to brilliant use.
Once I realised this I felt no more intimidated or unsure about the reliability or workings of the GP's than a S200, in fact I was so enlightened and amazed by the simplicity that I'm also now eyeing the MK4 Walnut stock Daystate.
What's different compared to a conventional PCP?
The energy and duration with which the hammer strikes the firing valve is precision electronically controlled.
How? The hammer is the core of a solenoid, a device so long in use that it made the first telephone ring. Momentum is provided by the electro-magnetic field generated by the coil of the solenoid and not a conventional coiled hammer spring.
We rolled electrical wire around a thin tube as kids and were able to shoot needles from the tube by connecting the device to a battery. In this case the hammer is the needle.
How does it know how much energy is needed for the hammer to strike the valve with predictable outcome?
It's got a chronograph built into the barrel shroud extension to tell the micro processor what velocity the pellet is doing. It also has an electronic pressure gauge which feeds info to the micro processor to calculate the energy needed for the coil to propel the hammer with predictable outcome.
In short this is what happens when the trigger is activated:
The trigger being a high quality micro switch release an instantaneous exact amount of electricity stored in an electrolytic capacitor to magnetise the solenoid coil. This value was calculated by an algorithm programmed into the micro processor which use data recorded from the previous shot and knowledge of the opposing air pressure on the other side of the valve.
Electrolytic capacitors are basically reservoirs which can be filled by a feeble current until full and then they can release a lot of energy in a very short and precisely calculated time, like a large sluice opened. This sudden surge of electricity is applied to the coil of the solenoid which excels the hammer which in turn hits the firing valve releasing a measured pulse of compressed air to accelerate the pellet down the barrel.
This concept is known as Capacitive Discharge Technology, CDT, and was brought to airgun design by Stephen Harper and David Snook in the eighties. Electronic camera flashes had been using the concept since early seventies, regulated capacitor discharge results in perfect exposure by a xenon filled glass tube and output is calculated by measuring elapsed time of light returning from the photographed subject.
This process was dubbed Mapped Velocity Technology, MVT by Daystate. In the electronic models without chronograph the rifle operates according to pre-set values and it is called Map Compensated Technology, MCT.
Advantages over mechanical devices:
Superior lock time due to an electronic triggering system used, five times faster compared to a sluggish chain of mechanical events to release the air. It takes a mere 5 milliseconds from trigger activation for the hammer to strike the valve fully open. By the time this happens a mechanical hammer would still be on its way to the valve.
The Daystate hammer is centered on its travel forward by a magnetic field, it does not even touch the inside of the solenoid coil, no mechanical wear is present which eliminates lubricants, a major cause of velocity inconsistency.
Another bonus to the use of electro magnetism to move the hammer opposed to a mechanical coiled spring is the lack of hammer bounce, resulting in very economical air consumption since the lack of wasted air and unnecessary turbulence behind the pellet affecting accuracy negatively.
A spring driven hammer can bounce back from the valve into the spring and gets thrown forward again resulting in another pulse of air released from the valve after the pellet started down the barrel.
When the micro processor of an electronic Daystate cuts the current to the coil the hammer force stops instantaneously. There's a weak spring only to return the hammer to it's starting position.
This obviously also makes a hammer spring cocking device unnecessary, the bolt is only used to seat the pellet. Air efficiency is phenomenal, I get 150 shots at 12fpe from a 205 bar fill. (The rifle counts the shots for me and a beep tells me it's down to 55bar and going off regulation. A glance at the chrony reading will confirm this.)
Because the trigger is simply a micro switch it beats any competition trigger hands down for sensitivity, no creep, no polishing of sears needed, imagine clicking a computer mouse with adjustable spring load, that's almost as smooth as it feels.
The processor knows exactly what pressure it's dealing with and at which speed the given pellet travels. Extreme spread is only dictated by the quality of pellets used.
The energy can be user dictated, you can tell it what velocity you want it to shoot your favourite pellet at.
The FAC GP's will shoot a 8.4gn pellet at 500fps up to 1010fps depending on what you set it at. (What gets most fiddled with on air rifles? Power output and consistency = hammer springs, regulators, the cumbersome fiddling to balance the two components, if not by yourself then by some "Guru" to whom the rifle gets shipped, man, do the courier companies love this!) With Daystate's MVT technology it's done PRECICELY with the push of a button, right there where you're sitting shooting, no spanners involved! I rest my case.
Some obvious questions:
How long does the battery last on a charge?
Very long, the circuitry is very power efficient. 5 tins of pellets between charges is not uncommon, if you live without access to electricity to charge the rifle you can even resort to a small 9 volt alkaline battery to power the rifle. It will turn itself off if not fired in 10 mins in case you forget to switch it off before torage. The battery itself also is no rocket component, it's made up of 8 normal AA penlight NiMh 1.2v cells (available on battery shelves in most shops) connected in series and shrink wrapped into a pack.
How do you know it needs charging?
The GP shows the voltage level on the display screen. The batteries can be topped up after every shoot without adverse effect being nickel metal hydride batteries.
How do you know the MVT rifle performs at the velocity set by you?
It displays the exact velocity of every shot.
What if you get caught in the rain with an electronic rifle?
The electronic circuit boards are coated with a water repellent varnish
and Daystate had a rifle in a tank at their IWA 2004 exhibit already which was sprayed with water for four days and it still worked.
How does the rifle know when you change to a different weight pellet?
It will realise it the moment the velocity deviates from the previous shot fired, it will then use the next two shots to calculate and adjust it's power to shoot the new pellet weight at the speed you chose.
It will also do the same if you change the velocity setting or refill the cylinder. It is intelligent enough however to realise you forgot to put a pellet into the breech when the chrony returns a zero value, it will not adjust immediately but will fire the next shot at the same speed as the last pellet, same goes for an extreme velocity deviation like shooting a cleaning pellet at 1500fps, it will wait for the next shot to see if it needs to adjust, if you keep shooting cleaning pellets it will adjust power to shoot them at
the speed you set the rifle at.
Does it need 3 shots after every switch on to do it's calculations?
No, if nothing changed i.e. pellet weight or cylinder pressure it will simply continue shooting as it was before switch off. Some very early models would need 3 shots after every switch off to get up to set velocity again, this has been improved by Daystate long ago.
What maintenance is needed?
None other than perhaps replacing the rechargeable battery pack after about 5 years and routine barrel cleaning which include cleaning of the chrony "eyes" in the shroud tip with a mascara brush like the girls use to apply mascara to their eye lashes.
The electronic circuits are of modular surface mount design so defective modules can easily and time effectively be unplugged and swapped out if needed. There's a chronograph, main board and display driver module, LCD display, pressure sensor, solenoid coil and a battery pack.
The crony is safely tucked away on the outside of the air stripper tube which sits in the barrel shroud extension, only four tiny holes provide access to the pellet path for the two infra red beams to measure pellet speed.
Unlike chronies with sky screens no external light is needed for the chrony to function. The air stripper tube is held in place by a threaded end cap on the shroud. No lead dust builds up on the chrony "eyes", I checked a GP with at least 3000 shots through it and could not find any lead dust on the IR Led's, cleaning pellets might be a culprit but I'll explain the solution to that further down.
Firmware updating is possible by the local agent in case Daystate makes a drastic change to the way the micro processor thinks. The one FAC can be set to warn when the pressure in the cylinder drops to a pre-set value, the other FAC cannot, but both display the pressure left on the LCD. The unfortunate reason for Daystate not making it possible for the user to simply download and update the firmware himself like camera and GPS firmware I guess is the FAC restrictions in Britain. It would be possible to illegally upgrade a 12fpe rifle to a FAC spec then.
The micro processor is also put to other good uses besides regulating the pellet speed, it displays voltage, pellet speed and bar left, it can also display shot count and charging status while the charger is plugged in, it even has a magazine count reminder for the models using magazines.
User input is accomplished by using the trigger when held down at switch on, the rifle then enters the menu mode and it can be set to user preference. The models without displays use audible signals for programming and communicating with the user.
There's not much to be improved on the principle or the consistency of these electronic rifles, so all that's left to change would be to add nice to haves.
I guess we might see the integration of a memory card to log and record shot strings and other shooting data downloadable to computer. Once this already generally used technology is incorporated, firmware updates could be effected by simply loading it onto the memory card and inserting it into the rifle. Data encoding linked with embedded rifle serial numbers can be used to avoid illegal upgrading.
It could be taken further, user preferences could be stored on the card and the rifle could respond to a specific user's card. No, that would mean I might have to share my GP, let's skip that idea! A stopwatch function would be more useful.
Trigger release could perhaps be achieved by breaking an infra red beam, either by mechanical device or finger, the latter would enable a bench shooter to fire the rifle without touching a trigger! Bench rules might have to be rewritten. Must admit though, bench rules do accommodate electronic triggers as they are. Jean Michel Jarre made music on an electronic organ by using fingers to break beams more tan 10 years ago already.
I cannot wait to see which manufacturer will be first to take the bold step to follow in Daystate's footsteps and adopt electronics in their rifles. All I know is that they will be years (decades?) behind Daystate who will remain the undisputed pioneers of electronic air rifle design.
Accuracy? These rifles are common at Nationals and Worlds, 'nuff said.
Some notes on the GP as such:
If you or anybody else for some reason (most likely to service the chrony) remove the barrel and top part of the action, take GREAT care when replacing it not to pinch the 3 core flex wire running to the chrony from the action. I have encountered two previously worked on GP's with pinched wires. The wire is routed between the barrel shroud and the cylinder in a perfect fit channel and through the action to the main board in an even
more perfect fitting machined channel. If it's not put back with greatest care two things happen: The barrel does not float above the cylinder as intended resulting in POI shift. Worse, the very thin conductor breaks inside the insulation resulting in a frustrating intermittent chrony malfunction with temperature or pressure change. This can only be
determined by using a continuity tester while manhandling the wire to see if it's broken inside the insulation.
If you have a GP and plan to use cleaning pellets, de-burr the chrony "eye" holes in the air stripper, the burrs on these tiny holes catch the fibres of the expanded felt pellet when it passes and the chrony beam is blocked resulting in a 0fps chrony reading. In this case the rifle will default to maximum power, still fully regulated and consistent, 20fpe in the case of the FAC and 12fpe in the non FAC version until the problem is rectified with mascara brush.
Last, don't EVER fire the rifle with the shroud end cap off, you will shoot the chrony and air stripper out the shroud extension resulting in a broken chrony wire. Encountered one such case, can happen.
Hopefully after reading all this you will also realise that the electronic Daystates are simply PCP's with the massive advantage of using proven electronic technology to achieve extreme consistency and accuracy. It's WAY less of a mystery than an entry level point and shoot digital camera's workings, desktop calculator or even electronic engine management on a scooter. You keep the battery charged, it keeps on shooting.
Discussion at: https://www.airrifle.co.za/threads/38781