14 replies to this topic

[Duke Wintermaul]

Alright gents, it's generally preferred among the NiC to include FPS data with new modifications. In the past, Chronographs have retailed around $100 and this keeps nerfers away from them. Instead, they simply do a range test. We all know the inaccuracies of range tests, so i'm not going to go into detail.

In the future, I see an NiC where all modification data is stored and collected with chronograph readings. This, combined with an accurate weight and size description of ammunition, will provide standard data on all blasters.

Before this can be realized, all NiC nerfers will have to invest in an expensive piece of hardware. I know many of you already have, i know i have. But who wants to spend $100 of something that doesn't even fire foam?

This airsoft chronograph is currently on sale for less than $50 shipped. I implore you all to purchase one.

[azrael]

Researched it, I recommend reading reviews. There seems to be a significant amount of people with problems. The same problems between different users - I think that speaks volumes for their QC.

[Coop]

Be careful with chronographs of that nature. That hole is pretty small so you'll be limited to what blasters/projectiles you can measure with it. Even if a dart CAN fit through that hole, even a small wall graze due to inaccuracy on its way through will distort your findings. An open top chronograph would be easier.

[koree]

Everyone buying a chrony is impractical. The assumption being made here is that people will become better experimentalists equipped with a chrony but that’s not going to happen. Without better skills/knowledge chrony tests are susceptible to biased data collection and cherry picking like range tests are.

Just as you can angle your blaster during a range test (unintentionally or otherwise) you’ll run into problems with chrony tests with dart mass. How accurately can the average nerfer measure the mass of their dart? I have access to an analytical scale, but most people will have to buy a new scale to get consistent results since even a 0.1 g difference will theoretically make a 10 fps difference on the Chrony.

Cherry picking data is always an issue as well. Take a look at the data I’ve posted here. See how there is that one dart that did get over 100’ that's not representative of the rest of the data? That’s the 100’ flat ranges everyone is referring to. Now here’s some chrony data collected under the same conditions each time. See how there’s a few darts that crept over the 200 fps mark? Very susceptible to cherry picking.




Also, chronies aren’t going to keep people from lying about their data, possibly so they can make money. Xplorer in Singapore gets very high FPS out of their LSs. I was getting around 200-250 fps in my RM kit depending on spring load with ~1.1 gram slugs. I needed to get an idea of what their darts weighed before I could make an actual comparison. So I asked, and when I got my hand on a few of their actual darts, it turned out I was lied to.



On the flip side of this, if someone is really interested in collecting good data for blaster modification and/or possibly contributing to Doom’s research and the NIC, you don’t need a chrony to do it. You can collect relatively useful data with a level and measuring tape. Also, reading something like this might help.

Edited by koree, 28 September 2013 - 08:47 PM.

[andtheherois]

Your future is bad and you should feel bad. I was going to post what Koreesaid, but he said it better. As we've seen, any data is easy to a manipulate. It wouldn't make sense for everyone to spend 50 dollars for one when a level taped to your blaster and a $10 measuring tape can get you data constant with legitimate tests.

[Duke Wintermaul]

Your future is bad and you should feel bad.

Okay

Perhaps it was premature of me to make this thread, but the fact still remains that this is the cheapest chronograph on the market. Yes, it's built by the Chinese with Chinese knock off parts. That's okay with me, Ive had this chrono for over 8 months and nothing has gone wrong with it. It consistently reads correct data that I have cross checked with existing chrono data either here on the haven or other nerf blogs/sites.

Yes, it has a small port that can be prone to 'tippage' and incorrect data. When this happens, I simply retest the corrupt shot.

However, I still feel it is worth the money to purchase this chronograph.

Do or don't, I simply wanted to inform the community that a cheap alternative to range tests exists.

[Tangerle]

These work, my school has these. You just need to not be unintelligent.

http://www.alibaba.c...Sensor_for.html

Edited by Tangerle, 28 September 2013 - 03:13 PM.

[Ivan S]

I can only speak from my own experience, but I've found chronograph testing to be extremely precise(e.i. consistent), and therefore not as subject to cherrypicking as ranges. Take a look at some chronied shots from my snapbow:

The readings are much more consistent than any range test I've done. Muzzle velocity is almost intrinsically more consistent than range, because range depends on muzzle velocity, as well as many other variables like angle, wind, and dart skip.

It doesn't make sense to use the beaver/0914 data to demonstrate inconsistency in muzzle velocity, because Beaver took his data at a range of different pressures/velocities intentionally, and the war data was taken from several different blasters. If you want to get an idea of how precisely a chrony measures the power of a blaster, you need to use just one blaster.

It is true that variation in dart mass leads to variation in muzzle velocity, but it also causes variation in range so I don't really see how that makes a difference when comparing the two methods. As long as you're using consistently weighted darts like slugs it shouldn't be an issue either way.

Do you need a chronograph to collect good data? Of course not. But it makes it much easier. And like Koree says, the rest of your set-up needs to be scientifically controlled as well.

Even if chronographs don't give better data, I think they're worth it because of their convenience. Waiting for daylight and good weather, going outside, setting up a tape measure, walking along and recording your shots every time you want to see what barrel length is best, or test how much a tank expansion helped, or see which of many motors works best is too much for my impatient soul. Having instant feedback right there in the shop is just way easier.

*breath*

Arguments aside, If you're looking for a cheap chronograph I recommend you either build one (not hard, I've done it). Or fire your blaster along a tape measure while video taping it and compare the frames. I usually use the later method and it works great.

Edited by Ivan S, 28 September 2013 - 03:56 PM.

[azrael]

I think data from a chrony, when collected in a reliable manner, is much more useful than the average range tests. Now, there are people out there who conduct meaningful range tests. I don't see them often. I don't see people taping levels to their blasters, etc, etc.

In any case, I think that a chrony can be a useful tool for anyone wanted to see the effects of their modding. You can see meaningful data, instead of just estimating results, or blindly following popular modding practices.


But that particular Madbull chrony is probably not a good one to buy. Even if Duke has had no problems with it, there are enough people on the internet who DO have problems with it to make me consider not buying one. And if the real deal 100+ dollar one has problems, then I would say that a Chinese knockoff is just as prone to having potential problems, if not more.

These work, my school has these. You just need to not be unintelligent.

http://www.alibaba.c...Sensor_for.html

Or you can build one? It's just IR emitters and detectors.
I just posted a homemade chrony on reddit.

Edited by azrael, 28 September 2013 - 04:16 PM.

[Tangerle]

Or you can build one? It's just IR emitters and detectors.
I just posted a homemade chrony on reddit.

Well mainly people who aren't capable or lazy could it would be better to buy. People would have to go through a long process to find and or buy the materials. Though some people easily could. I have most of the materials myself to build one at my house.

[koree]

It doesn't make sense to use the beaver/0914 data to demonstrate inconsistency in muzzle velocity, because Beaver took his data at a range of different pressures/velocities intentionally, and the war data was taken from several different blasters. If you want to get an idea of how precisely a chrony measures the power of a blaster, you need to use just one blaster.

I didn't, I linked other data for that.

Now here’s some chrony data collected under the same conditions each time. See how there’s a few darts that crept over the 200 fps mark? Very susceptible to cherry picking.

Also, I'm not saying that chrony tests are particularly prone to cherry picking, I'm saying that all measurements are. With your data you probably have an average of ~212 fps, however, most people in our community don't how to (or are unwilling) to use even the most basic forms of statistics and may report values such as 225 for an experiment like yours.

Edited by koree, 28 September 2013 - 05:43 PM.

[Zorns Lemma]

Chrono data is useless without precise mass measurements and how many people are going to get a precision scale?

[lech]

Would a kitchen scale be accurate enough when you weigh 50 or 100 darts at a time ?

[Roland The headless]

Huzzah! I have a reason to use my expensive crony!
I bought it years ago and used it maybe 5 times, now I will use it a lot.
If there is ant Spokane nerfers I will let them shoot there blasters over it anytime
(Maybe they will bring parts ) did I type that out loud, oops
anyway msg me
I can give some data if needed
Roland

ps I have a bullet scale is that accurate enough it weighs in grains and grams

Edited by Roland The headless, 21 December 2013 - 04:44 AM.

[chplnstone]

I have a basic sports chrony as a paintballer, and have used field chronies for blasters before, if a field is in your area it may be an option for testing. but instead of weighing darts and measuring fps, would an impact measuring device for measuring joules of kinetic force be easier?