Mailing List flyrotary@lancaironline.net Message #5183
From: Bartrim, Todd <sbartrim@mail.canfor.ca>
Subject: RE: [FlyRotary] Re: Cooling
Date: Thu, 8 Jan 2004 10:26:32 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
RE: [FlyRotary] Re: Cooling

    Is there a danger letting the temps of the rotor housings
    operate at a higher temp as long as we are below the melting point by a
    safe margin(say 350 vs the water cooled 200-250)?
    Ignorance is bliss!  :-)

        Another factor is that the thermal conductivity of oil is far less than that of water. Pure water is best for heat rejection, however as we know it is not practical in terms of boiling point and freezing point. As a necessity we use oil to cool the rotors and it does reject 1/3 of the rotaries heat.

        The oil cooling is limited to the inside of the rotors, where the seals on mine are viton and supposed to be able to handle higher temps, but the rest of the cooling system, likely wouldn't tolerate the higher temps.

        An example that oil cooling alone is insufficient is the turbocharger. It is fed with oil and water. If oil alone was used to lubricate and cool, the oil would begin to "coke" as it is overheated. For this reason I usually leave my EWP on for a few minutes after shutdown.

        I've probably already said more than I know, so maybe Lynn will expand on this.

S. Todd Bartrim
Turbo 13B
RX-9endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

        "Imagination is more important than knowledge"
                                        -Albert Einstein


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