McPhee Aviation

KS Avionics
Quality U.S.  made Engine Analysis Instruments

EXHAUST GAS TEMPERATURE (EGT) INSTRUMENTS monitor all cylinders and give an alert to short term problems and, most importantly, will warn you if a long term problem is starting to develop. This is the best system for informing the pilot of a potential long term problem. Aircraft designer Bert Rutan  recommends KSA.

If you really want the best then the Tetra II and Hexad II series EGT/CHT is the choice for the discerning aviator. You can monitor all cylinders with easy to read vertical analogue display - just line up the bars. This is a 4 or 6 meter system which either monitors only EGT, or switch to both EGT and CHT.

As may be expected, these systems are quite expensive - but you get what you pay for. They will save you a great deal more than the initial costs involved.

Other brands give you short term trend, as of course does the KSA, but the KSA is the only brand that gives you real and measurable long term trends for your engine. At a recent Oshkosh seminar on engine analysis instruments the speaker clearly favoured KSA for that feature alone. I subsequently spoke to Bert Rutan who waxed eloquent on  the virtues of KSA over all others. It really needs a demonstration of the instrument to explain how it works, but basically if one of the knobs down the bottom is changing its position in order to zero the instrument in cruise then you have a problem developing. The problem could be valves, rings or ignition but at least you know where to look before it is too late.

Another great warning device that can be added is Thermalarm for warning you against forgetting to enrich the mixture for decent.

CYLINDER HEAD TEMPERATURE (CHT) INSTRUMENTS warn of shock cooling of the engine and over-temperature by way of light or optional audio alarm. These are used by about 50% of glider tow-planes in Australia and come highly recommended by several parachute schools. Spending less than $500 can be regarded as a one-off insurance policy which saves cracked cylinders at great expense. These are also very suitable for air cooled motorgliders and flying school training aircraft.

The Thermal Stress Alert, apart from giving a flashing light when the rate of cooling exceeds a user setting (usually set for 30 deg F per minute but damage is not done till rate exceeds 40 deg F per min and if the temperature is high or near maximum temperature), also gives a continuous light when the CHT exceeds a maximum pre-set by user. Thus your valuable engine and cylinders are protected from shock cooling and overheating. Over the last 15 years over half of the glider tow aircraft in Australia have been fitted with a KSA instrument, and most owners would now say cracked cylinders are a thing of the past.

Aircraft involved in parachuting, aerobatic and training are all at high risk of cracking cylinders, and thus could really benefit from a KSA Thermal Stress Alert. If your aircraft does a reasonable amount of cross country work as well, then I would recommend the combined analogue CHT/EGT (Mixture Mizer II) which comes in the small 57mm version. If several people are using the aircraft I would recommend the CHT/EGT -2 which has two individual meters for EGT and CHT. As standard it comes in the 80mm version but the 57 mm version is available at a small premium. It is generally agreed by most owners that the expanded analogue scale of KSA is the best EGT they have ever used.

I can supply names of KSA users in your area.

Your EGT can be made even better with the addition of "Thermalarm" which warns you by way of a light if you forget to enrich your mixture on decent. Another great idea for the cross country pilot and it costs very little extra. A very small price to pay to prevent valve damage. An audio alarm can be fitted to all models.

McPhee Aviation has been selling KSA instruments for 15 years. We recommend KSA for their unrivalled reliability, and for the manufacturer's excellent after sales service.

www.ksavionics.com