Figured I ought to post some pictures of a refit of my karlsruhe.... Side view Gearbox and motor Can you guess what the white part is? Sub-Deck. The cannon fits in the large middle opening.
I did the math on it and by the time it is all said and done it should be at least the same weight, possibly considerably lighter, depending on how much excess material I remove from the unit.. (and assuming it works).
more pictures of parts... The pump impeller is 0.88 inches in diameter... and has not been cut off the stock yet. It was designed based off the book Centrifugal Pumps Design and Application Second Edition using its procedures and tables... If the motor is a good fit for this pump and I made the thing right I should get about a gallon per minute with a 10psi pressure rise for the cost of 6-8 watts... we will see... The cannon assembly is missing only the breech and barrels, although it does have a bunch of extra material that will be removed. this last picture is just for size comparison...
Lookin good! Can wait to sink her! Please throw some more pump photos up.. its hard to see what's going on there.
Well, I finally got the pump mostly put together... now I just have to make a restrictor for it... and get the rest of the internal junk situated... I may have to go back and make the impeller out of aluminum rather than plastic... for galling reasons...
We will see how she works. Should be a whole heck of a lot more efficient (assuming I Read the book right) as I spent the time with a pump design handbook and designed it for 1gpm at 10psi (numbers not 100% randomly chosen) targeted for 10,000 rpm (based on what loosely available data was there for motors). It is still a bit of a pot shot, but at least it is an intelligently guided pot shot.. The more I think, the more I am tempted to make the impeller aluminum, even though it takes an awfully long time to make out of aluminum. We will see how she does. I also still need to make the orifice and do some measurements.
Wow, that's some very impressive stuff. Any chance you might make some impellers and housings for 1/4" outlet pumps? Or let us know where to get this pump-design handbook?
Greg 10.000 rpm you say i have a few of my old corally handwound 540 type rc car motors here and am curious how they would do .. they make 35000 to 48000 rpm's @7.2 volt i know that on a battlers pump they didnt work, kept sucking the air in as they put the water out faster then the waterchannel could supply it i did test a bit .. 10 liters (2 .5 gallons ?) in 30 seconds, 20 ft in the air, 1/4 inch outlet on 6v lead acid battery. iowa was sinking till i turned the pump on she was almost jumping to the surface after the pump was on with a 27000 rpm motor (stock 27 turns 36 degree reedy conquest) Krijn
10,000 rpm was chosen as it was about 60% of the motors free rpm at 7.2volts... http://www.amazon.com/Centrifugal-Pumps-Design-Application-Second/dp/087201200X It ain't the greatest book, but we will see if it works. The thing about it is that you can use a slow motor with loads of torque if the impeller is large enough or a fast motor with a small diameter impeller to get the same results. The faster you spin the impeller, the more pressure you get at a given flow rate, until the point where you pull the pressure low enough in the entry regions of the pump or along the impeller vanes to vaporize the water. I doubt I will make any of these pumps for folks as it takes me about 6 hours to make all the parts. Add to that the aluminum impeller I think I need to make, and the total time will be about 12 hours...
Well,a few lessons learned on that pump... that is applicable to all pumps. Small diameter shafts are a pain in teh butt to align. I should have replaced the motor spindle with a 1/8" diameter shaft for a tight running pump it is IMPERATIVE that there be a ball bearing of some sort on the spindle that presses into a hole in the housing to line up the pump impeller Off angle pump impellers happen with small diameter shafts. I had to peene in one side of the hole to get it aligned sufficiently She needs about a 5-10 thou shim between upper and lower pump housing sections to get the impeller clearance correct I don't think the motor is getting up to speed Metal impellers... gotta have the metal impeller with these machinable plastics... plastic on plastic rubbing = weld/gall but for the good news 0.8-1 gallon per minute flowrate, crude measurement. Does not seem to have a vapor locking issue considering that the motor does not appear to be putting out the power at speed I thought, (need measurements of current, etc) this pump seems to work fancy tapered outlet works well. Very Very quiet. Now for a picture:
Not likely, they take far too long to make on my home equipment and I do not have the time to get set up to cast them or farm the parts out for someone else to make. If someone wanted to actually produce these for the hobby, we can chat about the files. and the outlet is the 3/32, IRCWCC 0.5 unit outlet
Well, I always try to do something completely different on each build or rebuild. This is it for the karlsruhe (the pump was an evolution not anything truly new). A breech that allows independent elevation control and has the standard IRCWCC restrictor. it is currently untested but so far it looks like it should work well. (assuming it doesn't fail structurally. it shouldn't but until it is tested, one never knows). it is also small enough to fit in one of the K's turrets. Heck, after this I have a whole host of things that will make it easier to make and align total size of the breech is: (excluding barrels) 0.628inX1.205inX1.606in Wreno, if you recall us chatting about elevation control a couple of years back, this is the result of that conversation. here are some pictures:
