Message

Bill Schertz
KIS Cruiser # 4045<= /DIV>

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

From: Russell Duffy [mailto:13brv3@bellsouth=2Enet]

Sent: 12/18/2004 6:08:31 PM

To: flyrotary@lancaironline=2Enet

Subject: [FlyRotary] Re: cooler thoughts

The problem might simply be=20 that the pulses are hitting high pressures and fatiguing the reasonably flim= sy=20 evap cores=2E There's also the possibility that the pulses hit a=20 resonant vibration at some point, which causes the failure=2E

It would be=20 interesting to see a trace of these pulses, and they may be important; but I= am=20 skeptical about them being the primary cause unless your cooler is near the=20= engine outlet, and you have rigid (solid metal) lines=2E

Hi=20 Al,

If I=20 thought a standard pressure sensor could catch the pulses, I'd be tempted=20= to put a scope on it=2E I just don't think it would be a conclusive test=20 though=2E Leon has told me some interesting stories that lead me to=20 believe in the pressure pulse theory=2E I also can't think of a better=20 explanation=2E I don't quite buy the cycling pressure theory, because=20 I'm only running about 80 psi at the cooler=2E I think the evap core=20 probably sees close to an 80 psi cycle between static, and=20 operating pressure=2E Also, I believe the leak started after a=20 good 20 minutes of flight, not on initial pressure at startup, which wouldn'= t=20 indicate that it failed on the pressure=20 cycle=2E

Fortunately, I=20 think the only point we need to prove is that evap cores are a bad idea for=20= oil coolers=2E

Cheers,<= /SPAN>

Rusty

------=_NextPart_84815C5ABAF209EF376268C8 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable One other difference=2E The Mazda cooler has a thermostat that bypasses the = oil until it warms up=2E the evaporator core has to handle all the flow even when cold= , so the evap core is seeing the high initial startup pressure=2E =20 Bill Schertz KIS Cruiser # 4045=20 ----- Original Message ----- From: Russell Duffy [mailto:13brv3@bellsouth=2E= net] Sent: 12/18/2004 6:08:31 PM To: flyrotary@lancaironline=2Enet Subject: [FlyRotary]= Re: cooler thoughts=20 The problem might simply be that the pulses are hitting high pressures and f= atiguing the reasonably flimsy evap cores=2E There's also the possibility that the pu= lses hit a resonant vibration at some point, which causes the failure =2E=20 =09 =09It would be interesting to see a trace of these pulses, and they may be i= mportant; but I am skeptical about them being the primary cause unless your cooler is = near the engine outlet, and you have rigid (solid metal) lines=2E=20 =09 =09Hi Al,=20 =09 =09If I thought a standard pressure sensor could catch the pulses, I'd be te= mpted to put a scope on it=2E I just don't think it would be a conclusive test tho= ugh=2E Leon has told me some interesting stories that lead me to believe in the pressure= pulse theory=2E I also can't think of a better explanation=2E I don't quite buy th= e cycling pressure theory, because I'm only running about 80 psi at the cooler=2E I th= ink the evap core probably sees close to an 80 psi cycle between static, and operati= ng pressure=2E Also, I believe the leak started after a good 20 minutes of flight, not on i= nitial pressure at startup, which wouldn't indicate that it failed on the pressure = cycle=2E =09 =09Fortunately, I think the only point we need to prove is that evap cores a= re a bad idea for oil coolers=2E=20 =09 =09Cheers,=20 =09Rusty=20 =09 ------=_NextPart_84815C5ABAF209EF376268C8--