Longer throw without changing the driver !! :) Prototype is done and now it's time for testing.. ( more beam shots)

sorry Chicago X if Idon’t agree with you regarding using PM as to continue a debate outside the thread.
to me,PM are reserved for private messages regarding private infos… such as selling, buying, trading or some other stuffs that you don’t want anybody else to know… definitely is not a place for trading insults.
and if they do feel the need to continue to trade insult out of the thread… then they seriously have a problem.
heated debates should always be leave it at the thread, wether its good or bad… it’s for others to see and chime in if they want too… if not they could always stays in neutral corner.

Rufusbduck is probably right about me, for saying my style is a bit defensive and argumentative, but that could always be expected from anybody when they’re trying to defend their ideas.

it’s coming down to a simple solution really… if you tried to make your point cross and others just don’t get it… just leave it at that. :slight_smile:
don’t try to convert them… let them be… sooner or later they will learn themselves :wink:

NERD FIGHT!!!

LOL!

You guys need to step back and really look at what you are doing. You are fighting over terminoloy.

Maybe the OP wasn’t 100% correct. Who really cares? Part of the reason this site was founded was to get away from the Nerd Nazis like they have on CPF.

The OP was just experimenting and having fun with a hobby he enjoys. I suspect some of the comments completely crushed his desire to share anything in the future.

Since I am not a flashlight super expert, I tend to learn more from people who also are less expert.

To be honest, the smartest people on here are way beyond my level and I don’t read or care about the minutiae of how a beam of light is measured.

Ever notice how terrorists use the open and free societies that they so despise to allow them the freedom to perform there acts of terrorism? It has occurred to me that CPF could have sent over some plants to sabotage our free and open forum with contentious remarks. There have been some calls for more moderation here. That would be a shame and a victory for the “terrorists” The great American statesman, Benjamin Franklin spoke on this long ago

“Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety.”
Benjamin Franklin, Historical Review of Pennsylvania, 1759
US author, diplomat, inventor, physicist, politician, & printer (1706 - 1790)

As for more Moderation, my old Aunt Anna had a favorite saying just before she poured herself another drink”

“Be moderate in all things, including moderation.” :wink:

Less than what? Finger on the hose is less max flow potential. That can become less actual flow after a certain point, as I posted.

The physics can go either way as long as there is enough pressure and flow potential to maintain the flow rate of the full open condition. If the hose is already constricted on flow-rate relative to max flow on the inlet, then your cover-it-all answer is correct. It’s just that you’re only right under certain conditions, and under others the results are different.

The whole point of my posts in this thread are that there are too many that don’t examine the variables, and allow for the exceptions or conditions that others may be providing. Condescending posts like the one above are not helpful - in fact they are insulting in their implicit and unspoken assumptions.

lol.. reminded me of this song..

http://www.youtube.com/watch?v=Dg2DHRAqWy0

I appreciate that. Some standard assumptions are not standard to others. We use 3/4” or if I have to 5/8” garden hoses even though some of the old faucets we have here aren’t capable of full potential. Besides, when running garden irrigation off the demand 220v pump some of the standard assumptions don’t apply. :slight_smile:

I’m mostly a stats guy, a favorite line a friend uses is a boy and his dog have 3 legs each. A simple view might be that they are both male and the dog is missing two legs . . it’s a wrong view.

My ax to grind on this is the discourtesy in the discussion. If NZ Shooter’s example was a wrong assumption relative to the flashlight science, THAT should have been the discussion - which is NOT achieved by using a simple argument. It’s a lot more appropriate to explain when the assumption behind the example can be valid, and then why that assumption doesn’t apply to the flashlight example. Too few seemed to be arguing the wrong thing because they don’t know the flashlight science and that is when we should stay out of that discussion or approach it with a lot more courtesy than many who should be walking are running and gunning.

@GottaZoom: When you put your finger on the hose to make the jet smaller, less water flows. No matter what preconditions you assume, thats the case. Unless you have a pump that is set to a fixed amount of water and therefore increases the pressure. But what would that pump do if you closed the hose? Make your pipes burst?

"A boy and his dog have 3 legs each." Whats that meant to tell us? I can interpret so many senseless stuff into that sentence, so whats the point?

Hammertime! No, flow is a combination of pressure and capacity. Reducing capacity increases pressure but that is only a flow reduction when the capacity drops far enough that the existing system pressure cannot rise enough to maintain flow. At that point increased pump pressure would be needed to maintain flow or the volume then drops.

LOL.

That’s the point . . is a stat and so it will be interpreted wrongly. Doesn’t stop people from thinking they know something when they hear a stat, though. Think of it as a variation on the blind men and the elephant story. Or thinking that finding an answer on the internet is learning the answer. A sensible person will recognize they need more info to form a more complete picture, and then courteously ask questions so they might learn something.

I think everyone is tired of reading the useless runaway arguements from the past week. Lets all agree to keep it flashlights with a show of respect to NZ . innuendos and remarks should be where they belong, history. Those that showed up after some of recent fireworks looking for easy targets now that some of the dust has cleared with off the cuff slick remarcks, STFU..please

Amusing song, but I was hoping for more aladeen.

+1

So you have a pump in your house? How does your pump know that you are blocking the water and not just opened the hose only halfway?

Pumps usually try to maintain a fixed pressure.. not a fixed amount of water flowing, no matter what pressure.

I was quite busy lately (I moved) and so I missed all the fun... (and fortunately the nasty parts, too.)

I still feel like adding some remarks... (an optics related thread without me? No way ^_^ )

Be careful with analogies: Do a water hose and a flashlight really have that much in common? Try obstructing part of the beam - does the light come out at higher speed or throw farther?
(There's some fun though: Cut out a disc of cardboard about 2/3-3/4 of the flashlight's aperture's diameter and use some removable glue to fix it in the center of the front lens, compare with&without ^_^ )

Use proper terminology: A big part of this discussion was caused by misunderstanding each other. That's the reason why terminology was invented - to make sure everyone is talking about the same.
("Brightness" btw is not that well defined... Earlier it was defined as luminance, nowadays it's recommended to use it for subjective, non-quantitative perception. I think it's safe to say that this fresnel mod gives a brighter spot. It might even be valid to say that the little experiment I supposed above might give a brighter spot, though I'd find that quite confusing to say ^_^ )

I’ll try to help here. Feel free to step in GottaZoom. Simply stated, the issue arises when the hose id is larger than the supply. When that is the case pressure in the hose is LESS than pressure in the supply pipe. Therefore the pressure in the hose can rise when you put your finger over it until it hits the same pressure as the supply. Up until that point flow stays the same due to the pressure rise in the hose. It is after this point that the flow actually falls.

I think we have different opinions about what "put your finger on the hose" means. That could explain most of the confusion..

My science tells me the increase water velocity will make up for the decrease in flow area, i.e. flow rate stays the same. Common sense tells me when you adjust the faucet it takes longer to fill up containers. So I went out to the garage and open the faucet about half-way. Counted how long a small bucket filled up water coming out of the hose unhindered(took about 10 seconds). Emptied the same bucket and filled it up again but this time I partially blocked the end of the hose (about 75% blocked) and it took about 10 seconds also for the bucket to fill. I guess my results means I’m going to side with GottaZoom and NZShooter on the flow debate.

As DrJones pointed out, all this is irrelevant. The speed of light is fixed and can't be faster than it is. (Yes, I understand this oversimplifies it)

i’m glad you can chime in on the subject Drjones… maybe now we can put this all corrective term of brightness behind and move on the original purpose of this little experiment… which is just an IDEA.
an idea that maybe can be use to further more testing and creation to brighter lights without spending a lot of money in the future :smiley:

Never mind the science, common sense should tell you it would take longer to fill the bucket at 99% blocked.

I have always found it useful to exaggerate an issue to see it more clearly.

In electrical circuits, one can emulate a constant current source by having a high voltage power supply in series with a high resistor. For example a 300 volt source in series with a 300 ohm resistor will give 1 amp to a 1 ohm load. It will also give 1 amp to a 2 ohm, or 3 ohm load. In other words, it would appear to be a constant current source.

This water and hose example appears to be a constant flow source because the relatively high resistance of the length of garden hose. Within certain changes in the restrictions at the end it can appear as a constant flow source.

In the above electrical circuit, placing a higher resistance load it becomes apparent the the supply is NOT a constant current source. (a 600 ohm load will only draw 1/3 amp)