To Bench Test or Not?
04-22-2008 | 11:05 AM
#51
RE: To Bench Test or Not?
ORIGINAL: captinjohn
Why do you say engines are run at WOT (wide open) all the time on a stand?? If they are its a mistake by the operator.
Why do you say engines are run at WOT (wide open) all the time on a stand?? If they are its a mistake by the operator.
It gets done all the time, I didn't say I was condoning it. I agree with you, for break in all you need to do is generate enough cylinder pressure to seat the rings. All that takes is short bursts of power, not continuous WOT. Alternating throttle settings and making sure the engine is not overloaded or overheating is more important than WOT for any length of time. I think it is done because it is easy to crank it up on the stand and let it rip, whereas you can't normally fly around at WOT for long in the air.
I do recall Ralph C mentioning that the T-6 racers will break in a G-62 by putting it on the stand with a race prop on and letting it run WOT for a couple of gallons, though. Of course, that prop doesn't load the engine too heavily and lets it rev pretty high. And I am sure they know enough to not let it get too hot along the way.
Mark
04-22-2008 | 06:44 PM
#52
Senior Member
My Feedback: (1)
RE: To Bench Test or Not?
ORIGINAL: mmattockx
Pat,
I will take a look at it. The laptop is no problem.
What type of thermocouple are they using? Do they clip or bolt to a cooling fin (I seem to recall hearing that mentioned elsewhere in this forum)? The kart racers have nice ones that replace the washer under the spark plug, so they get a reading right from dead center of the head in an area of minimal cooling. It has been a while since I looked at them, I will have to do some research.
Mark
ORIGINAL: Pat Roy
Although the Eagle Tree is pretty expensive it provides quite a few user functions that others don't, and they are small. You don't need a live telemetry dashboard unless you do a lot of ground testing. You can't watch the dashboard when flying... The data logger they have (base unit for all the systems) is extremely useful. Buying the optional USB serial port for routing the data link to the outside of the fuselage is a very nice feature to have unless you like removing the hatch to download data. All of this presumes you have a laptop to facilitate gathering data. Obtain a couple extra thermocouples for different engines. That also allows room to screw one up experimenting with different mounting locations.
Although the Eagle Tree is pretty expensive it provides quite a few user functions that others don't, and they are small. You don't need a live telemetry dashboard unless you do a lot of ground testing. You can't watch the dashboard when flying... The data logger they have (base unit for all the systems) is extremely useful. Buying the optional USB serial port for routing the data link to the outside of the fuselage is a very nice feature to have unless you like removing the hatch to download data. All of this presumes you have a laptop to facilitate gathering data. Obtain a couple extra thermocouples for different engines. That also allows room to screw one up experimenting with different mounting locations.
I will take a look at it. The laptop is no problem.
What type of thermocouple are they using? Do they clip or bolt to a cooling fin (I seem to recall hearing that mentioned elsewhere in this forum)? The kart racers have nice ones that replace the washer under the spark plug, so they get a reading right from dead center of the head in an area of minimal cooling. It has been a while since I looked at them, I will have to do some research.
Mark
Mark,
Eagle Tree uses what I call a "wrap" thermocouple. It wraps around the cylinder, although it can be tricked into attaching under a bolt and washer. If the cart people have a basic two wire thermocouple adapted to fit under a plug I want some!!!! The downside of the Eagle Tree Thremocouple is that it typically has the resistance sensor at the front of the cylinder, which is not the hottest point on the engine regardless of placement height. The stuff used at work is a bit more sophisticated[)]
04-22-2008 | 10:06 PM
#53
RE: To Bench Test or Not?
ORIGINAL: Pat Roy
Mark,
Eagle Tree uses what I call a "wrap" thermocouple. It wraps around the cylinder, although it can be tricked into attaching under a bolt and washer. If the cart people have a basic two wire thermocouple adapted to fit under a plug I want some!!!! The downside of the Eagle Tree Thremocouple is that it typically has the resistance sensor at the front of the cylinder, which is not the hottest point on the engine regardless of placement height. The stuff used at work is a bit more sophisticated[)]
Mark,
Eagle Tree uses what I call a "wrap" thermocouple. It wraps around the cylinder, although it can be tricked into attaching under a bolt and washer. If the cart people have a basic two wire thermocouple adapted to fit under a plug I want some!!!! The downside of the Eagle Tree Thremocouple is that it typically has the resistance sensor at the front of the cylinder, which is not the hottest point on the engine regardless of placement height. The stuff used at work is a bit more sophisticated[)]
A quick google of "spark plug thermocouple" netted these:
http://www.sportdevices.com/sensors/index.htm
http://www.challengerwest.com/stratomaster.htm (scroll down a bit, they look to have ones for multiple sizes of plugs under SENDERS)
http://www.performancetrends.com/Dat...TMTempPicture3 (scroll down 5-6 items and they show a K thermocouple for 14mm plugs)
Lots of stuff out there to look at based on this.
Mark
04-22-2008 | 11:53 PM
#55
RE: To Bench Test or Not?
ORIGINAL: Pat Roy
I've used ones similar to the 14mm version from Performance Trends before and they broke rather frequently. I'll take a closer look at some of the others. Thanks for the links
I've used ones similar to the 14mm version from Performance Trends before and they broke rather frequently. I'll take a closer look at some of the others. Thanks for the links
Mark
04-23-2008 | 10:47 AM
#57
RE: To Bench Test or Not?
Pat, Eagle Tree also has a K-type thermocouple and extender module for the FDR. It comes in two flavors, one for EGT and also one for CHT. The CHT comes with crimp on electrical connectors sized for putting it under spark plugs and the EGT comes with mounting hardware to put the probe into the exhaust pipe. You can use both EGT and CHT with one extender module as it has two connectors on it. The K-type thermocouples are available seperately.
