Discussion in 'General Airgun Chat' started by RobF, Mar 6, 2019.
Seems interesting... ta for him for the heads up.
This is what I have just written on another forum.
I have not used this device or the LabRadar which is a larger similar system which has been available for some time. However, I have used multi thousand pound doppler radars on a regular basis which are much more powerful and capable than this system can ever be and it is not as simple as is claimed. The positioning of the radar relative to the barrel is critical. Minute adjustments in both line and elevation can make large differences to the measured values. Using just one radar you would never know this but it was standard practice on my trials to use two radars which had to agree. Getting agreement was very difficult.
All these systems have to measure a number of velocities as the pellet travels away from the radar. They then curve fit the points and extend the curve back to the barrel to obtain the muzzle velocity, they do not measure the muzzle velocity directly. The curve fit used by the radar set is critical to getting an accurate muzzle velocity. On the units we used you could choose the curve fit you thought most appropriate and there could be significant differences to the "measured" muzzle velocity simply by changing the curve. Luckily we could also download the raw measured data and make our own curve fits which was much more accurate. The validity of the curve fit is also dependent on the number of data points available which, as said above, can vary greatly depending on the accuracy of the radar setup relative to the gun and the bullet trajectory.
Despite the claims, these types of systems are affected by weather conditions. On some days we were unable to fire simply because the radars could not track the bullets for a significant distance and obtain sufficient data points for accurate muzzle velocities. The screens we were using showed the data points and sometimes had what looked like a snow storm on them after a very short distance. This system will not show this so you will never know if the data is of good quality or bad.
The only real advantage of a radar system over a conventional chronograph using a lighting system of some kind is if it can download its raw data in the form of speed vs range data points. This must be the raw data not the curve fitted data many of them produce. The raw data can then be used to produce drag curves, not BC values which do not require more than two points. The drag curves will be much more accurate than BC values but you have to ask is it really necessary? For most people the answer is no.
So, these systems are not simple to use despite the claims. The trouble is most people will never know unless they have more than one set.
We had a bash with the one from the worlds ( i think )
It Didn't like a springer
That wasn't from the worlds, but lent to us by an owner for testing for them and national competitions. I think the problem with that was that it used a microphone to record the data and process it... and as you say a springer with a stock silencer was too quiet to trigger it. That unit could record data out to about 40m, there's a more powerful version than can do 50m but it's not allowed in the UK, presumably because the wattage is too high for use without a license, or it might divert flights from Heathrow, dunno. So I guess that's why it needed triggering or else it could be picking up a bluebottle 20 yards out. This FX one seems to limit the reading to about a foot, so maybe that's why it can be left on and doesn't need a mic.
Interesting insight from Miles, I guess like all of them if you're just using one then you only are getting a sample of one.
The Labradar ive seen in action seemed to do a bloody good job to me?
One of our members has a LabRadar which we've tested inline with conventional chronos (think Polish) to give us an idea of the accuracy of the IR units. We found that in ideal conditions i.e. no sun, the IR chronos were within 2fps of what the LabRadar was showing.
Btw the mic on the LabRadar doesn't trip the timing, it just tells the unit to expect something (soon) to track in it's field of view. It's designed to be activated by a rifle crack so a quiet springer is always going to be a problem
Considering it's tracking a .177 pellet, the LabRadar does a very good job right out to 30yds+, down at Bisley I've seen them track right out to 400yds and are the de facto tool for working accurate loads as you have some wonderful data to work from.
conventional chronos in use at FT events
Has potential for a club unit due to its high chance of not being shot time will tell however
While I do not have a LabRadar I have been sent detailed data from one which I analised using the same techniques and software I used to analise shell and bullet flight. The results were quite frankly rubbish unless all the laws of aerodynamics have been changed. This was due almost certainly to the curve fit used in the unit to clean up the data. I would not fully trust the values one gives, certainly not to any significant range since it is not a tracking radar which requires a moving head with a narrow beam. It is a pity as I was originally hoping that they could be used to supliment some of the radars we were using in gun trials over short ranges. Unfortunately not so, we had to keep on using multi million pound tracking doppler radars.
The fact that they are being so widely used for multiple purposes only illustrates the dangers of people, who quite frankly do not know what they are doing, being given new wonder tools. I was lucky in that the people I was working with had vast experience and were national experts in tracking projectiles with radars. However, even they could get it wrong sometimes and get rubbish data from the large radars which only showed up when I analised it fully. That is why I had to attend the trials and use the full software system to make sure everything was working, simply looking at the data did not suffice.
no few hundred quid shortcut around a multi million pound doplar wotsit then . Shame .
What about them 2 nutters with high speed cameras then ? Tracking shells in flight . great fun
I think i need to start a new thread .............
Flight follower has been used for years now but it is tricky to get analytical quality pictures with bullets let alone pellets. There are also limits to what can be derived from the pictures though it is a useful if expensive tool.
The Lab Radar was not to be used as a short cut for the larger radars but more to try to fill in missing short range data. Unfortunately it was not suitable.
Many users on US gun forums have also reported problems with their readings.
LabRadar and the new FX radar can be used as a chronograph but do not expect them to be perfect or infinitely superior to the normal chronograph.
As you say Miles .
I think these radar devices are going to be useful as chrographs
This one ?
That’s the one...
I think that for our limited purposes the LabRadar is pretty good as long as you set it up properly and aren’t shooting a quiet rifle. It might not be as accurate as the multi-million Doppler radars you’re used to working with but then we’re dealing with chucking small chunks of lead not a rail-gun HVP...
The FX unit is a different matter as in my experience units like this tend to push the wow features and skimp on important stuff like clock speed.
that's the fella .
Quite a lot of waffle , but mesmerising footage............I am actually Barry Norman in disguise you know
....and.......Today's Top Tip
If a nasty artillery man is aiming his big gun at you ..................Hide behind lots of melons .
You don't pay a penny extra for this you know......
I agree but, as you say, it has to be set up properly and how many people are going to get tired of the correct setup process and take short cuts. On one of my trials we were using a similar fixed head radar which was giving readings 10% in error. Not enough to notice as we only had one unit on that trial but obvious on analysis as the bullet needed a negative drag to get where it landed. A 10% error could be the difference between a legal and illegal rifle and is more worrying than the reported 100% errors from some shooters which are immediately obvious.
I was also dismayed to see a video posted by a famous small arms ballistician from a shoot in the US where a lot of visiting shooters were invited to shoot and have their bullets tracked by LabRadar. The positioning of the radar was hopeless, way off to the side of the shooters and this was someone who was supposed to be an expert.
As for rail gun HVPs on an early trial one of our managers was hit in the chest by a rail gun launched projectile, didn't even bruise him. Well it was one of the early trials.
That's a tank, not artillery. If a tank or artillery man heard you say that you would definitely be placed in front of the melons.
Is that big 'un off a tank then ? (The one at 10.20 mins in ) Flippin' 'eck
I think that 'big' gun is a Russian 152mm howitzer.
Luckily if you didn't have a row of melons to hide behind if you ran really fast and managed to get about 18km away you'd be safe...
Adding to this reminds me of this photo from Malaya late 50's. The chap at left with an 'X' is my Dad and this was the first (and only) attempt to take a field piece on patrol through the jungle.
The brass wanted their arty support and weren't interested in the logistics of moving heavy stuff through the jungle, so they spent a week moving this gun approximately a mile across rivers etc only to find that (as predicted my Dad) the thick jungle canopy made firing the thing impossible.
I do believe that this was destroyed in an enemy attack *cough* so luckily they didn't have to spend another week getting it out.
Good mixture of weaponry including an Owen sub-machine gun and FN FAL's, though Dad always favoured a shot-gun loaded with candle waxed lead shot.