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I am trying to understand this plumbing scheme. Where in the circuit are the water pumps? Are they after the "Y splitter", or on the line going from the core to the Meziere inlet? The pumps are likely to do better at 'pushing' the liquid rather than pulling it, so you want the outlet of the pump going into the evaporator core.

One operational concern is if you are operating on one core, and the thermostat calls for the second pump, when it turns on, it is going to be delivering 'cold' fluid that has been stagnant in the core to the engine. you 'might' end up with oscillations in the cycling of the pump. Will this cause a problem?

Bill Schertz
KIS Cruiser # 4045

----- Original Message -----

From: Russell Duffy

To: Rotary motors in aircraft

Sent: Monday, December 22, 2003 8:39 PM

Subject: [FlyRotary] dual EWP plumbing?

Greetings,

As I continue on the painfully slow process of de-BUC-ing the plane, I'm looking into plumbing options for the EWP's. The Meziere adapter has two inlets, and one outlet to the engine. The plan is to run the one large outlet to a Y splitter, then to each evap core. Since there are two core outlets, two EWP's, and two inlets to the engine, it's mighty tempting to let each EWP handle only one core. It's certainly the simplest way to plumb it. BTW, I do have one way valves, so there will be no backflow through the pump that's off.

In a way, this makes sense to me, because I can thermostatically control one of the pumps, and leave the other one on all the time. In normal cruise flight, cold weather, and certainly descent, one core will be enough. Eventually, I may install an effective cowl flap to cut drag at cruise, and the plumbing can certainly be re-worked if needed then, or I can just let both pumps run. The worst case situation is that one pump fails on climb, but the EM-2 (that Tracy is still adding features to <g>) will tell me the temp is going up, and I'll reduce power, or increase speed.

One other possible benefit is more even flow through the cores when both pumps are on. Haven't I heard some of you say that you've had difficulty getting the water to flow evenly though parallel cores?

In my usual masochistic way, I offer this idea for your abuse, or is that the other list :-)

Cheers,

Rusty (learning more about exhaust every day)