|
Guys,
We have two schools of thought going in this discussion and have had for some time..........One
opinion has the bottom of the expansion tank plumbed to the "Outlet" of the pump (as Tracy does &
others)..........The other has the bottom of the expansion tank plumbed to the "Inlet" of the pump
(as Al G., Mark S. & others do)..........I believe the inlet position came from the "Stewart Racing
Pump" site...........The rational being that this was the lowest pressure site of the cooling system and
would not subject the system pressure "Cap" (on the expansion tank) to both system and pumping
pressure..............Take your choice as both methods work and are flying successfully..........I just
wanted to point out this difference and remove confusion...........
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from Tracy Crook <tracy@rotaryaviation.com>: --------------
Re-reading Kevin's post I'm not sure I understood it the first time. In fact, the more I read it the more confused I get : )
Maybe this will fill in the blanks. The pressure at the port in question is dynamic pressure due to the water pump, not expansion. It might suck some air on cool down when the engine is shut off but will immediately flush it out on startup. The other point is the bottom port of expansion tank should go to the top (outlet) of the pump housing, not the inlet. Therefore there is no bypassing of the radiator.
Tracy
On Thu, Sep 10, 2009 at 9:31 AM, Tracy Crook <tracy@rotaryaviation.com> wrote:
As Ayn Rand said, "There are no contradictions. If you see one, examine your premise."
Why would you want a large flow through the expansion tank?
Tracy
On Thu, Sep 10, 2009 at 2:02 AM, kevin lane <n3773@comcast.net> wrote:
I was embarrassed to ask about this originally, but it seems I am not alone with questions. having viewed several flying cooling system flow designs at the rotary round-up, perhaps it isn't that critical.
one aspect I trying to understand is the expansion tank. there shouldn't a big flow thru there, right? if the pressure is greatest at this far rotor housing top port, then it must be lower in the expansion tank, and a slow flow will take place towards the expansion tank, right? the small diameter line will tend to push bubbles thru and they will separate in the expansion tank. so, if they enter the tank above water level, this line will suck air from the expansion tank as the cooling fluid cools and has a lesser volume, right? not good. if the expansion tank feeds the cooling circulation system by T'ing into the water pump output, then it is all on the higher pressure side of the system, and the air in the expansion tank won't have a tendency to be sucked into the circulation? is the design intention to keep the expansion tank under pressure, rather than have it part of the flow [circulation]? if the expansion tank was plumbed into the water pump inlet port, then a second circulation route is created, which doesn't involved the radiator [rear rotor port to tank to water pump, thru engine block to rear port....], right?
as far as the bubble line for the radiator it seems that it would work by allowing trapped bubbles in the higher end of the radiator to travel uphill to the expansion tank. is the pressure at the radiator also higher, as with the rear port?
enough questions. clear as mud, right? kevin
|