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Old May 01, 2007, 10:31 PM
Smoke me a Kipper
fritzdecat's Avatar
Cedar Grove North Carolina
Joined Oct 2006
1,214 Posts
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Perry Pump?

Newbie question here...

What does a Perry pump do? I recently bought a Saito 125 and have heard thru the grapevine people using a Perry pump with this engine.


Any help or information greatly appreciated. Thanks

Regards, FritzDecat
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Old May 02, 2007, 01:43 AM
Airplane Gearhead
Central N.Y.
Joined Jan 2005
1,142 Posts
Well...starting with the Saito...right off hand I would say that it doesn't really need a pump, unless you want or need to put the tank in a less than ideal location.

Some guys use a pump or Cline or Iron Bay regulator to crutch a bad tank location, but if the tank is in an acceptable spot, none of the above are really necessary. (4 strokes require a different style of pump plumbing installation than a 2 stroke, and unless it's really required, it can be more of a P.I.A. than it's worth..JMO)

The Perry pump was introduced in the mid 70's. I still have my first K&B .61 (2 stroke, bought it new in '75) with the backplate pump and large bore pressure carb and love it. Have quite a few of them actually, and the K&B's w/ the .375" bore pump carb will put out some power! (especially the 6.5 and 7.5cc pylon and ducted fan engines)

For one, the pump allows you to use a larger than typical carb. throat (for more power) because the carb is no longer dependant on venturi suction for fuel draw.

The pump is used to bring fuel to the carb, independant of tank pressure (no muffler press. is needed or wanted) and because of the built-in check valves and regulator, the tank can be located just about anywhere you want to put it. (which can come in handy in certain designs)

The Saito 1.25 is an excellent engine, and under ordinary circumstances, it will be fine without a pump. Most times the guys using a pump or Cline/Iron Bay are using them in aerobatic types, where they have the tank back over the C.G. and the engine will not function properly without some help.
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Last edited by proptop; May 02, 2007 at 02:01 AM.
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Old May 02, 2007, 08:19 AM
Smoke me a Kipper
fritzdecat's Avatar
Cedar Grove North Carolina
Joined Oct 2006
1,214 Posts
Thanks for the enlightened response Proptop that clears up that mystery.

I am using this engine in a Sig Four Star 120 and the tank location seems to be perfect fit so I'm glad I don't have to use the pump. Nice to know I have the option though.
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Old May 02, 2007, 09:03 AM
Registered User
United States, TX, Weatherford
Joined Dec 2006
1,655 Posts
More info. The Perry Pump uses engine vibrations to oscillate and pump fuel. So it does not require any source of power except to be mounted correctly to pick up the necessary energy. There are several versions, one used to pump oil for smoke operations. The important thing about them is like the Cline/Iron Bay (a pressure feed system) is that you do not have to add batteries to make them work. Perry has a web page, do a search and check them out.

Cheers,

Chip
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Old May 02, 2007, 02:08 PM
Airplane Gearhead
Central N.Y.
Joined Jan 2005
1,142 Posts
Yep...there are several versions...slipped my mind (it was in the wee hours of the morning in my first post )
The one Chip mentions is the V-20 or "shaker" pump.
The one I was thinking about is the V-30 that uses crankcase pressure/vacuum fluctuations to operate a diaphram.
And, of course the smoke oil version...
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