Micro Air Pump

[jlabow]

I just received my latest parts shipment from Sub Driver (thanks for the quick shipping!). Even though the pump is pictured next to a quarter I didn't realize how 'micro' it was until I actually saw it. Roughly how long will this pump take to blow the 27 ox ballast tank in the 1/72 Gato?

Thanks,
Joel

[trout]

Joel,
check out this link 2/3rds down the page I did a test

http://forum.sub-driver.com/showthread.php?1793-Revell-Gato-1-72-Newbie-no-more-Part-duex/page3&highlight=Pump+test

I put two pumps in my Gato. Originally I did not use a resistor and they were very fast using the 11 volt battery. Concern was it will prematurely burn them out so I put a resistor in. So, it slowed my ballast blow times. I have a video that shows the rise time too.

[He Who Shall Not Be Named]

Stick a 22-Ohm, 1/4 Watt resister in series with one of the power wires to the MPC and you'll drop the recommended 11.1-volt voltage down to about the 8-volts the little pump can handle safely.

With the pump so configured, it will blow out the GATO ballast tank (on or near the surface, with little back-pressure) in 90-seconds in either SAS or LPB mode.

David

[jlabow]

Thanks. How did you control the second pump? How big a resistor? I was planning to use a 7.2 volt main battery...will this cause other problems?

Joel

[jlabow]

David,
Thanks as usual. Most of what I know about WWII sub practice comes from the books of E.L Beach and Richard O'Kane. Both state that subs usually used HP air to start the surfacing process and then finished off with LP air. If this is true combining gas and snort should be pretty realistic. Let me repeat the question I asked trout...Will a 7.2 volt main battery answer the mail?

Best regards,
Joel

[He Who Shall Not Be Named]

David,
Thanks as usual. Most of what I know about WWII sub practice comes from the books of E.L Beach and Richard O'Kane. Both state that subs usually used HP air to start the surfacing process and then finished off with LP air. If this is true combining gas and snort should be pretty realistic. Let me repeat the question I asked trout...Will a 7.2 volt main battery answer the mail?

Best regards,
Joel

I qualified on a TENCH class boat. Normal practice was to come up to periscope depth, look around, blow bow-buoyancy, start the LPB, full rise on both planes, wait for the sail to broach, open the main induction, turn on the low pressure blower, get the watch up on the bridge and wait the fifteen minutes it took to blow the main ballast tanks dry. Or, if on the snorkel, start the LPB from periscope depth, blow bow buoyancy, and reapeat the above drill. Only air from the banks used was for the squirt needed to put the up angle on the boat.

7.4-volt source, you can drive the MPC directly off the source without need of a voltage dropping resistor.

David

[trout]

I wired the pump in parallel with the first one, positive of pump two to positive of pump one, and negative of pump two to negative of pump one (pump one had the controller on it). So switching pump one on, turned on pump two also.

Thanks. How did you control the second pump? How big a resistor? I was planning to use a 7.2 volt main battery...will this cause other problems?

Joel

[alad61]

I just received my latest parts shipment from Sub Driver (thanks for the quick shipping!). Even though the pump is pictured next to a quarter I didn't realize how 'micro' it was until I actually saw it. Roughly how long will this pump take to blow the 27 ox ballast tank in the 1/72 Gato?

Thanks,
Joel

David beat my response...

I have been running my gato on a 7.2v 3600mah pack from the get go and I can tell you straight off the bat with a full battery I can get my her from full deck awash to waterline in 75 seconds in the tub. It does take a few seconds longer in the wild which I put down to water with more solids in it. However getting towards batteries end it has taken just on 2 minutes, but I generally am sailing to dock by then with the forward planes on a little rise and it does look pretty cool as it gets from just having the sail half out of the water to near proper surface running depth by the time she is near the dock.

[He Who Shall Not Be Named]

David beat my response...

I have been running my gato on a 7.2v 3600mah pack from the get go and I can tell you straight off the bat with a full battery I can get my her from full deck awash to waterline in 75 seconds in the tub. It does take a few seconds longer in the wild which I put down to water with more solids in it. However getting towards batteries end it has taken just on 2 minutes, but I generally am sailing to dock by then with the forward planes on a little rise and it does look pretty cool as it gets from just having the sail half out of the water to near proper surface running depth by the time she is near the dock.

Your 'top end' at only 7.4-volts, hight throttle on the surface, Alec: is it fast enough for you? Those motors are wound for 12-volts.

David

[alad61]

David it cuts through the water with ease giving off a nice wake and bow wave, I actually dialed back the throttle to 80 for ahead & 75 for reverse on the epa and it gives a good scale speed. Infact there was an ex navy vet who had seen them in action and he complimented me on its look an scale speed. It does tend to slow off after a solid 1/2 hour run but all I do is dial it back to 100 and still menace the yaughties for another 15 minutes or so. I' m even thinking of putting another one together...

[jlabow]

Thanks to all!

Joel

[He Who Shall Not Be Named]

David it cuts through the water with ease giving off a nice wake and bow wave, I actually dialed back the throttle to 80 for ahead & 75 for reverse on the epa and it gives a good scale speed. Infact there was an ex navy vet who had seen them in action and he complimented me on its look an scale speed. It does tend to slow off after a solid 1/2 hour run but all I do is dial it back to 100 and still menace the yaughties for another 15 minutes or so. I' m even thinking of putting another one together...

Well, that's excellent news, Alec. I never tried it with anything less than 11.1-volts. Nice to know. Thanks.

David