PreCharger Homemade

[Silence]

Okay, I'm glad that's all sorted out !

[Silence]

What are your (everybody's) comments on PreCharging? Is it a good challenge to APHs, given the information that I have posted and you may have? Clearly, my opinion is that PCgHs are great--and no, I'm not going to post the reasoning again, so please read the posts above.

Is it possible to turn an existing thread, such as this, into a poll? If so, I'd like some information on this--and information on changing thread names, given the following information.

I'm also thinking about designs for other water guns filling specific roles, following the theme of this thread--using a new system for a more efficient assault soaker. These other concepts aren't as revolutionary (if I say so myself)--they include CPS for a sniper soaker, springs for shotguns, etc. I'm thinking about putting these in new threads if the name of this one can't be changed into a more encompassing one that captures my theme. Comments, anyone?

[SSCBen]

What sort of poll options would you like? I can attach a poll to a thread fairly easily.

[Silence]

My theme, for this thread and others, is to use new pressure systems to add more variety and performance to homemades--and for this thread, the pressure system is PreCharging. Appropriately, I would like to measure the amount of criticism and support for PreCharging. I was aiming for a poll along these lines:
Question: "How effective would a PreCharger homemade be?"
Option 1: "superior"
Option 2: "reasonable"
Option 3: "I don't know."
Option 4: "average, but extra work"
Option 5: "surpassable"
Option 6: "inferior"
Thanks for the offer, Ben. @ all voters: As in most polls, please post your comments and reasons for voting in any specific direction, especially if your vote is negative.

This thread, while still alive, probably will do better once I actually finish my PCgH and post more information/images. Thanks for all the support, everybody--I'm probably not going to BUMP (Bring Up My Post) this thread for a while, but expect to see it again in a month or two. I might even write an article in SSC's homemades section once I'm done.

Once again, thanks, Ben.

[SSCBen]

Poll attached. Let me know if you need anything else done.

I'm going to hold off voting myself until I see a Pre-charger homemade water gun in action. I'll wait for your water gun to be completed first, but if I find the time, I might construct one myself to see how viable they are.

As for bumping, you can do that as long as it doesn't become abusive. I remember once at iSoaker.com there was a user who bumped his thread 6 or 7 times in a single day because he wasn't getting a post in his thread (had it occured to him that no one else was online?). Just don't do that and you'll be fine.

[m15399]

"Surpassable"
It is probably among the best air pressure designs, but if it were large enough (like Ben's) you shouldn't have to pump it up much. You could make a pumpless powerpak with a few piston chambers.

[Silence]

Thanks a lot, Ben. That was a quick response--I guess we're on SSC all day on weekends . As I said, I probably won't be posting too much on this thread for a while, but since this is a poll now, I will be monitoring it. Have you used any of Buzz Bee's commercial PreChargers? They're pretty nice, but as I wanted fixed in PCgHs, they have pretty small streams and water compartments. But I guess that's okay because pure water is better for soaking.

By the way, I wasn't really talking about BUMPing just to keep threads "alive" (which it doesn't really do--it just turns off members). I just meant that I, and others, won't be posting too often and that this thread may disappear off the first "Homemade water cannon" page. Yes, I know BUMPing is annoying--there was this one thread where, in the middle of perfectly good posts, the thread starter just posted the word "BUMP." I guess I just used poor terminology .

@ m15399: When I saw that you had typed "Surpassable" I thought you were catching a spelling error (yes, I had opted to take the lazy route ). After reading my old post in a frenzy, I realized that it had been your vote .

But now to be serious: by "Surpassable," did you mean that PCgHs are better than or worse than standard APHs? I just realized that there may have been some confusion, becuase I had meant it to mean that standard APHs can surpass PCgHs, while your actual comment appears to contradict that. Thanks for the feedback, but please respond to clear up this confusion.

Naturally, I opted for "Superior," and not just because I started this thread . I like PCgHs for all the reasons stated above.

[m15399]

I assumed it meant "there are better things out there". If we were comparing to APH, then I would have voted differently.

[Silence]

Okay, I'm just making sure you didn't mean, "It can surpass most water guns," or something like that. Earlier, but not now, I didn't think it matched your comment--I must have misinterpreted your reason.

[Silence]

I've decided to post what I expect will be my final diagram for what I believe to be the first PCgH. It is basically my version of the design that Ben and m15399 proposed, because I always have to get the last word . The only change I am currently making with the design is to make the tube comprising the second check valve slanted 45 degrees, hopefully making the grip more comfortable and moving the pump farther back into a more comfortable position.

A tentative but completely radical change might include a "displacement pump." Essentially, it works by displacing water in the pump tube instead of pushing it out like a piston. I will post a more detailed explanation of this in a new thread in the "Homemade water cannon" forum.

EDIT: I decided to draw a final diagram in the end. I think the design is nice with the slanted tube, and, as I forgot to mention, it makes for better linear and laminar flow. Hopefully, the slanted tees will have a curve like those used in the images of Duxburian's APH.

[Silence]

As usual, I've been refining my PCgH concept to make it more practical. It's really been my major goal to complete before summer break (in six weeks), although I will probably have to use the leftover PVC to create some (mediocre) guns for the other team; nobody will want to play against somebody with a hopefully crazy gun .

The latest diagram (posted above), while not to scale, still portrays a gun that is too disproportionate. I don't feel like doing another drawing, so I will just point out the changes.

The gun appears to be too bulky; for example, the pump is only about a third of the length of the gun (I was aiming for 1/2 or 2/3). In addition, the PC is a bit too big; but both of these problems can be solved by shortening the PC (maybe making it a bit wider). This will also move the grip to a much (much!) more comfortable and aesthetically pleasing location. After this change, the PC will be less than half its current length but much wider; hopefully, this will not render the PC piston to be too ineffective.

If I remove the on-gun water reservoirs and the backpack reservoir ball valve (which would be too expensive, bulky, and extravagant), and increasing the length and width of the slanted PVC pipe, I can allow the base of the pump piston to be farther back. This will allow for a longer and more proportional pump. Of course, I won't overdo this part, because that would make the grip be too far to the front of the gun again. The nozzle and pump will protrude to the front much farther than they do now, especially if I use a conical nozzle (which I will).

All in all, the soaker will be much better, and it will look a bit more like m15399's explanation earlier in this thread, with the major difference being that the PC will be shorter and possibly wider.

What does everybody think? I'd like to know if any of my new proposals are too outlandish, and if neccessary, I will draw a diagram to aid you. I'm going to build this very soon, so if I don't see any more posts, I'll just go ahead. Yes, I know that it doesn't sound like I'm actually going to build anything besides the weak APH that I already have, but I will.

[Silence]

A more detailed analysis of pressure and dropoff in PreChargers

After more careful consideration, I have concluded that PreCharger soakers do not experience reduced dropoff after all. If you PreCharge a soaker to 45 PSI--3 times the atmospheric pressure at sea level--then you'll have exactly 3 times as much air, mass-wise, as you would have in a comparable standard air pressure soaker's PC. This also means that you'll have 3 times the pressure of a standard soaker after any specific number of pumps, and because this is a constant ratio, you will experience the same power dropoff percentage. PreChargers do not experience enhanced performance only at lower PSI, which would be the only method of decreasing dropoff.

However, a PCgH can still provide much more effective operation than an APH can. First of all, given a pressure of 45 PSI after PreCharging, you will have three times the standard pressure after any given amount of pumps, though the pumping difficulty will also be the same as an APH's pump resistance after the APH has three times as many pumps. Let's say that a comparable APH's shot drops from 75 PSI to 15 PSI; this would mean that the given PCgH's PSI (after an equivalent number of pumps) drops from 225 PSI to 45 PSI. Because the final PSI is 45 instead of 15, I had earlier assumed that the pressure gets cut off there instead of at one atmosphere, meaning less dropoff (though with a sudden end, not with a slower dropoff rate); however, the initial PSI is 225 instead of 75, meaning you'll have three times the performance throughout, and you still experience significant dropoff.

But there is one more factor that must be accounted for: another purpose of PCgHs is to reduce the number of pumps required to reach maximum pressure, and given three times the amount of air (remember, that is by mass, not by volume), you can do so with only a third of the amount of pumps! This also prevents the increase of PSI to 225, which is practically impossible, unsafe, and probably unneccessary for our purpose. If you're content with 75 PSI, you only need to pump three times as much; however, because you're constantly fighting three times the pressure, pumping a PCgH at 75 PSI is like fighting 225 PSI with an APH. Buzz Bee Toy's commercial PreChargers use pumps with similar diameters to those of standard air pressure soakers, which means increased resistance (actually quite noticeable, but still pleasant), and you need to pump less. Another reason for pumping less is that the PCs are less than half the size of comparable PCs in standard air pressure soakers, and because of water conservation, the stream is smaller than that of comparable standard air pressure soakers.

Assuming a PreCharger's initial pressure is 45 PSI (as compared to one atmosphere, approximately 15 PSI), and assuming the final pressure is 75 PSI (the same as a standard air pressure soaker), it is easy to assume that the PreCharger has limited dropoff. However, this is not true, as the flow is just cut off at a certain PSI; and one can also argue that he or she could stop a standard weapon at 45 PSI and charge it up again, possibly using a wider pump to require fewer pumps. However, PreChargers accomplish this much more efficiently, using extra air in order to obtain the performance that a user gets by compromising a standard gun's performance--because in a standard gun, water is actually left inside the PC to keep the pressure up. Also, if one used a wider pump in a standard gun and used the inefficient and thus inferior method to cut off the shot at 45 PSI, he or she could not change the amount of PreCharging--the pump's diameter cannot be changed, so difficulty will occur if the maximum PSI must be changed, while a PreCharger can have different amounts of PreCharging PSI, trading shot time for pump speed and maximum pressure. This extreme flexibility and efficient design make PreChargers greatly superior to standard air pressure soakers, whether homemade or commercial; and PCgHs fix the small PC capacity and other problem found in Buzz Bee Toy's current PreChargers.

[st_jimmy]

What I dont like about the design is the whole piston part. First of all, I'm sure it would be difficult to effectively implement, as you would have to create a seal that holds under intense pressure. Also, it seems like such a tight seal would create some friction, making it ineffecient for pumping, although perhaps that is not significant.

[Silence]

Hey, welcome to SSC.

I agree that the piston makes PCgHs slightly more complex than APHs, and thus gives them a greater potential for unreliability, but I seriously don't think it's a major problem. In general, homemade parts are rock-solid, and as an example, homemade pumps are fine just the way they are. Besides, I plan on using washers and a thick O-ring to keep everything nice and firm.

[joannaardway]

I think that your hypothesis about pressure is wrong.

A pump of 1/2" ID with a tank pressure of 100 psi (simple number to work with) will force against 19.6 pounds of force, regardless of it being an APH or a PCgH.

I've got a lot more to say, but I've got other things to do - I'll finish my statements tomorrow.