Oil cooler and MLG fairing questions

[rbowen]

I have two questions for you veterans who have "been there, done that."

First, does the oil cooler for the IO-540 use a vernatherm? My M-7 oil temp runs very cold in the winter (like 140dF). I made a foam plug for the NACA air scoop which blocks air to the cooler. On a test flight the oil temp. only got up to 185 dF (per the EDM 700), with no oil cooler air. Seems if the cooler used a vernatherm feature, the oil would bypass it until reaching the set temperature. If no vernatherm, are you sealing off the air intake in the winter? ...partially or entirely?

Second, the plastic fairings around the spring main gear cracked underneath, at the split in the fairing (now big pieces missing). So I dutifully ordered replacements, fitted them to the gear, painted and installed the J-trim and installed on the airplane, only to have one crack and another big piece blow off. I obviously don't have the technology right to seal the crack in the fairing. How are you attaching these fairings so they don't self-destroy?

Any suggestions will sure be appreciated.
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Bob Bowen
2003 M-7-260C

[a64pilot]

No, the oil cooler does not have a Vernatherm, the engine does. Not to be a smart ass with that comment, I make it because the oil cooler is the responsibility of the Airframe manufacturer, engine obviously isn't. The vernatherm works backwards from a car thermostat. On a car the thermostat opens when the coolant is hot to allow flow through the radiator. On the airplane the vernatherm opens when the oil is hot, closing off the bypass which forces oil through the oil cooler. When the oil is cold, there is basically a Y. Bottom leg of the Y is from the oil pump and one top leg is the cooler and the other bypasses the cooler. When cold both top legs are open so there is some oil flow through the cooler and some bypassed. When hot the bypass leg is closed and all oil flow is through the cooler. This is why blocking oil flow through the cooler even when oil is cold will help raise oil temps.
If I were to block airflow through my oil cooler, I would want something more accurate than the factory temp gauge

Sorry, I know nothing of the spring gear.

[belandd]

how cold is it outside when you are trying to fly?

While your indicated oil temperature is low you have to be careful about letting oil flow into a cold oil cooler.

It is normal for a winterization kit to block air to the oil cooler but you have to be careful to monitor the temperature of the oil.

It is easy to over temp the oil if you climb up into a warm thermal layer even if it is cold on the ground.

That is why some winterization kits are adjustable from the cockpit.

Don't know where you are operating or at what temperatures.

I know that some of the operators in Alaska continue to operate at temperature of 40-50 below. I think anything colder than 20 below is crazy but then I am not trying to make a living with a piston engine.
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Silly Billy Charters and Tours
Valdez, AK.

[a64pilot]