Probes & sensors :
 
 
     

What you are looking at is best described as "quality engineering." J.P. Instruments' fast response probes offer speed and accuracy that is unmatched in the industry. The chart represents an independent and scientific study conducted by General Aviation Modifications Inc. (GAMI) on 7/02/01.

The curves on the graph (displayed to the right) were generated by GAMI, on a 6 cylinder IO-540 engine. Brand new probes were placed on each cylinder, 3 inches from the exhaust flange. The distinction shown here is the performance of "grounded" and "insulated" probes. It is clear that the ungrounded (insulated) are to slow to respond to all temperature changes. It is also worth noting that insulated probes, starting at the same  point as grounded probes, never achieved true temperatures. The ungrounded, insulated probes were 3/16" in diameter, supplied by Electronics International. And JPI's grounded probes were only 1/16" in diameter. At the cherry red temperatures of 1600' F,  E.I.'s larger  diameter probe has more surface are and so radiates more energy away, losing temperature at a rate of T'/ This is another reason JPI uses thin probes and not sluggish probes. When comparing probes, there has been various theories put forth regarding "probe response time."

Thermo Electric Co., a leading manufacturer of high response thermocouples states; response time is  "The amount of time necessary for temperature change to be detected and indicated by the sensor." There are two primary thermocouple types, Grounded Junction (used by JPI, Alcor and Insight) and ungrounded, insulated, junction (used by E.I.). "Some of the typical response times encountered are as follows: Insulated (ungrounded) 4.5 seconds and Grounded 1.7 seconds, while using a 1/4 inch O.D. Sheath." This is important - especially during leaning - only a fast response probe will identify peak. A slower responding probe will "peak" too late or not at all, which will cause the cylinder to run far to lean  - with detonation and possible engine damage. Temperature information processed by the EDM is captured by fast response JPI temperature probes that accurately measure the small temperature changes. Slower responding, ungrounded do not see the temperature change because the change is averaged due to their slow response.

Do confuse Accuracy and Resolution. Reading one degree increments, does not guarantee the instrument is accurate to one degree. JPI displays in one degree increments and is also accurate (TSO) to +/- one degree. Other brands want you to think because they read in one degree increments that they are actually accurate to one degree. THIS IS FALSE and in most cases they are only accurate to +/- ten digress.

In an attempt to make their probes last longer, some companies have increased their probes mass, or diameter, which by its design, sacrifices accuracy. you will note from the curves in the graph, that he Electronics International probes never really achieve the true temperature; so when the turbine limit is 1650' and you set 1650' using an E.I. probe, is the turbine over temperature?

JPI's grounded probes are manufactured using a space-age material, Hastaloy-X, that can withstand the harsh sulfur atmosphere  of temperature exhaust gas and uses them in all its gages;  including the legendary EDM 700.

So now you can see, that id accuracy and response are key factors in making your decision, then J.P. Instruments is the only way to fly.

CDT Probe:
The Compressor Discharge Temperature (CDT) probe, is installed just after after the inter-cooler. The probe is installed with a #40 stainless steel clamp. A large clamp is supplied to fit around the air port leaving the inter-cooler.
  Included with Probe:  
1 Thermocouple type K probe
1 Stainless Steel Clamp Thimble
1 Stainless Steel Exhaust Seal Washer
1 Stainless Steel Screw Type Clamp
2 Ring Terminals
2 Screws and nuts 6-32 X 1/4
1 Fiberglass tube 1/2" X 4"
CHT Adapter Probe:
The bayonet Adapter probe 5050‑A has a captive 3/8‑24 boss that is screwed into the base of the cylinder. The probe has a screwdriver slot to facilitate tightening. NOTE: Required original equipment that has a Red Line may not be replaced by the EGT‑701 TIT or CHT installation. This includes but is not limited to all aircraft with adjustable cowl flaps and on aircraft with placards on the instrument panel showing a climb air speed, for cooling, different from the best rate of climb air speed.

The cylinder head temperature (CHT) helps the pilot protect his engine against the threat of excessive heat. Most General Aviation aircrafts take have one factory CHT probe that accommodates the hottest single cylinder of the four or six cylinders. The hottest cylinder is determined by by extensive flight tests. In Lycoming engines, all cylinders are drilled to accommodate a CHT bayonet type thermocouple.
  Included with Probe:  
1 CHT Piggy-Back Adapter thermocouple probe type K
2 Ring Terminals
2 Screws and Nuts 6-32 X 1/4"
1 Fiberglass tube 1/2" X 4"
CHT Gasket Probe:
Most factory installed cylinder head temperature gages utilize a bayonet or screw‑in resistance‑type probe that occupies a socket in one of the cylinders. This probe is not compatible with the thermocouple probes required for the EDM's. The spark plug gasket probe, PN M‑113, replaces the standard copper spark plug gasket on one spark plug. Choose the upper or lower spark plug, the one that provides the best correlation with the other temperature probes. The probe is usually placed on the plug that receives the most direct cooling air. Due to the spark plug location, the gasket probe may read 20oF higher or lower than the factory probe. If the discrepancy is greater, be sure the spark plug gasket probe is mounted on the top spark plug. An adapter probe is available to occupy the same socket as the factory original probe.
  Included with Probe:  
1 Gasket thermocouple probe type K
2 Ring Terminals
2 Screws and Nuts 6-32 X 1/4"
1 Fiberglass tube 1/2" X 4"
CHT Probe:
The bayonet probe 5050‑T has a captive 3/8‑24 boss that is screwed into the base of the cylinder. The probe has a screwdriver slot to facilitate tightening. NOTE: Required original equipment that has a Red Line may not be replaced by the EGT‑701 TIT or CHT installation. This includes but is not limited to all aircraft with adjustable cowl flaps and on aircraft with placards on the instrument panel showing a climb air speed, for cooling, different from the best rate of climb air speed.

The cylinder head temperature (CHT) helps the pilot protect his engine against the threat of excessive heat. Most General Aviation aircrafts take have one factory CHT probe that accommodates the hottest single cylinder of the four or six cylinders. The hottest cylinder is determined by by extensive flight tests. In Lycoming engines, all cylinders are drilled to accommodate a CHT bayonet type thermocouple.
  Included with Probe:  
1 Bayonet thermocouple probe type K
2 Ring Terminals
2 Screws and Nuts 6-32 X 1/4"
1 Fiberglass tube 1/2" X 4"
CRB Probe:
All wiring must be type K thermocouple wire. Do not splice ordinary copper wire in any temperature probe circuits. Locate the access hole in the carburetor near the butterfly valve. Remove the screw plug and screw the CRB probe into the carburetor throat. No drilling or machining of the carburetor is necessary.
  Included with Probe:  
1 CRB thermocouple probe type K
2 Ring Terminals
2 Screws and Nuts 6-32 X 1/4"
1 Fiberglass tube 1/2" X 4"
EGT Probe:
Determine the locations of all holes before drilling to ensure that nothing interferes with the probe, clamp, clamp screw or wire. Do not mount EGT probes in slip joints. The model M‑111 EGT probe will fit any engine having existing holes in the exhaust stack of between 0.125” and 0.250.” If no hole exists, drill a 0.125” hole and ream to fit. It is important that each probe be mounted a uniform distance from the exhaust stack flange. A nominal distance of 2 to 4 inches from the exhaust flange is recommended. If the recommended distance is impractical due to obstructions, slip joints or bends in the exhaust system, then position the probes a uniform distance from the flange as space permits. Careful matching of probe position will provide the best temperature readings. Insert the probe in the exhaust stack hole such that the tip of the probe is in the center of the exhaust stream. Tighten the stainless steel clamp and torque to 45 in/Lbs. Cut off excess strap close to the screw. The probe warranty is void if the probe is mounted in any type of a slip-joint.

Radial engine exhaust, require a larger EGT clamp (supplied) to fit the 2.5 inch exhaust pipe. The EGT probe is installed in the same fashion as a Lycoming or Continental engine and should be placed between the exhaust pipe flange and the accumulator at a distance of 2 to 3 inches form the engine exhaust flange. Cylinder head temperatures are measured with a spark plug gasket type probe placed under the front spark plugs. Refer to the engine manufactures red line and set the EDM-700 appropriately. Front spark plugs will read 15 to 20 degrees cooler than the rear plugs. Do not route the EGT/CHT harness in with the ignition harness. Do not extend the yellow thermocouple leads with copper wire.
  Included with Probe:  
1 Thermocouple type K probe
1 Stainless Steel Clamp Thimble
1 Stainless Steel Exhaust Seal Washer
1 Stainless Steel Screw Type Clamp
2 Ring Terminals
2 Screws and nuts 6-32 X 1/4
1 Fiberglass tube 1/2" X 4"
Fuel Pressure Sensor 5-32 PSI 1/8 NPT:
  Included with Probe:  
1 Fuel Pressure Sensor
5-32 PSI 1/8th NPT
   
 
 
 
 
 
IAT Probe:
The IAT and CDT probes are the same as EGT probes and are installed similarly to EGT probes. A large clamp is supplied to fit around the air port leaving the inter‑cooler. Alternately a 1/8” NPT fitting is available. IAT will be shown in the digital portion of the display as, for example I25  IAT.
  Included with Probe:  
1 Thermocouple type K probe
1 Stainless Steel Clamp Thimble
1 Stainless Steel Exhaust Seal Washer
1 Stainless Steel Screw Type Clamp
2 Ring Terminals
2 Screws and nuts 6-32 X 1/4
1 Fiberglass tube 1/2" X 4"
Manifold Pressure Sensor - 0-60 inches of Hg. 1/8NPT:
  Included with Probe:  
1 MAP Sensor
1 T-Fitting
0-60 Hg. 1/8th NPT Buy One Now
   
 
 
 
 
 
OAT Probe:
Install the OAT probe, PN 400510 in the airframe manufacturer’s recommended location. If this is not possible, place the OAT probe in clean airflow such as in a cabin air scoop or on the underside of the wing away from engine heat or exhaust. Remember, the engine is operating with temperatures in excess of 1500°F. Just a little hot air or conductivity from the engine can cause the indicated OAT to increase by 10 to 20°. It is recommended that the installation be done similar to the antenna installation instructions of AC 43.12‑2a “Acceptable Methods, Techniques and Practices.”
  Included with Probe:  
1 OAT thermocouple probe type K
2 Ring Terminals
2 Screws and Nuts 6-32 X 1/4"
1 Fiberglass tube 1/2" X 4"
OIL Pressure Sensor - 0-160 PSI - 1/8 NPT:
  Included with Probe:  
1 Pressure Sensor
0-160 PSI  1/8th NPT
   
OIL Probe:
The Oil Temperature Probe is installed as a supplemental oil temperature indicator. Continental Engines: The ‑C part number is for all Continental direct drive engines and is installed in the left (pilot side) front oil galley by removing the existing 3/8 or 1/8 inch NPT plug (see figure below) located on the front, pilots side of the engine. Insert the optional JPI oil probe supplied in the kit. For 3/8 inch NPT installations, use the supplied brass adapter. An alternate location is on the top, front of the engine on the pilot’s side, where the probe is inserted vertically. There are two 1/8 NPT plugs close together. Install the probe in the position that is above and to the rear of the nearby position. The original oil temperature gage and sensor must remain installed in the aircraft.
  Included with Probe:  
1 P/N 400505 -C or -L, OIL probe
2 Ring Terminals
2 Screws and Nuts 6-32 X 1/4"
1 Fiberglass tube 1/2" X 4"
RPM Sensor Bendix Non-Pressurized - fits any Bendix:
  Included with Probe:  
1 P/n/420815-2 Fits any Bendix ( -20, -200, -1200 Series, Teledyne TCM -1200 is same as Bendix) Non Pressurized Magneto
   
 
 
 
 
RPM Sensor Slick Non-Pressurized - fits any Slick:
The Compressor Discharge Temperature (CDT) probe, is installed just after after the inter-cooler. The probe is installed with a #40 stainless steel clamp. A large clamp is supplied to fit around the air port leaving the inter-cooler.
  Included with Probe:  
1 P/n/420815-1 Fits any Slick (i.e.: -4000, -6000) Non Pressurized Magneto
   
   
TIT Probe:
The standard TIT probe  with a #48 clamp is placed in the exhaust stack accumulator to a maximum depth of 1/2 inch and approximately 4 inches from the turbine inlet if possible, on the waste gate side of the turbine. The EGT‑701 input is a high impedance and is compatible with the aircraft factory installed TIT probe. The EGT‑701 TIT cable may be connected in parallel (piggy back) at the TIT probe (preferred), or at the aircraft TIT gage. Be sure to match the red and yellow wire color codes. If your aircraft is using the factory original TIT probe and gage, you will be required to calibrate the EGT‑701 for that probe. Follow the procedure describe later in this manual (in section 30).
  Included with Probe:  
1 Thermocouple type K probe
1 Stainless Steel Clamp Thimble
1 Stainless Steel Exhaust Seal Washer
1 Stainless Steel Screw Type Clamp
2 Ring Terminals
2 Screws and nuts 6-32 X 1/4
1 Fiberglass tube 1/2" X 4"
 
     
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