Engine monitoring systems for towplanes

Hey, gang,

Soon we will be putting an overhauled engine on our Pawnee, and I am wondering if anyone has had experience with or has comments on engine monitoring systems on towplanes.

I am thinking a basic system with all 6 cylinders CHT (and EGT?) monitored, a shock cooling warning system, and data logging. Would monitoring other parameters be useful, also? If so, what parameters (adding sensors adds up $$$)?

Is such a system useful and helpful for our type of flight duty cycle (e.g., towing)? Do the shock cooling warning systems work for our very unique type of operations (I guess they are just an alarm if the rate of CHT drop exceeds a set value?)? Is the data logging useful for monitoring/predicting engine health and life? Am I overthinking/overkilling this issue?????

Thanks,
Jim

A graphic engine monitor will show CHT and EGT for each cylinder and
you'll spend more time looking at it than looking out the window. Please
read this article
https://www.avweb.com/news/features/Shock-Cooling-Time-to-Kill-the-Myth-230134-1.html.

On 9/6/2018 4:03 PM, wrote:
Hey, gang,

Soon we will be putting an overhauled engine on our Pawnee, and I am wondering if anyone has had experience with or has comments on engine monitoring systems on towplanes.

I am thinking a basic system with all 6 cylinders CHT (and EGT?) monitored, a shock cooling warning system, and data logging. Would monitoring other parameters be useful, also? If so, what parameters (adding sensors adds up $$$)?

Is such a system useful and helpful for our type of flight duty cycle (e.g., towing)? Do the shock cooling warning systems work for our very unique type of operations (I guess they are just an alarm if the rate of CHT drop exceeds a set value?)? Is the data logging useful for monitoring/predicting engine health and life? Am I overthinking/overkilling this issue?????

Thanks,
Jim


--
Dan, 5J

We went with 6 cyl CHT only.

What I will say is that after the first year.. we don't really stare at it.

BUT.. it exposed some horrible standardization (our own fault) among the tow pilots.

I believe it was worth it's money from that standpoint alone. We didn't discover the operational error until we got comparing notes of temps amongst a few of the pilots.

JP

On Saturday, September 8, 2018 at 5:32:18 AM UTC-5, wrote:
We went with 6 cyl CHT only.

What I will say is that after the first year.. we don't really stare at it.

A Recording engine monitor might be best. As noted engine monitors do tend to increase the heads down time. And looking at the data after the flights might actually be much more useful.

They are quite good at identifying baffling that isn't installed or working right.

They are also very good at helping keep the engine cool, as most experts agree that keeping the CHT's under 400F will extend the life of the engine.

Brian

On Friday, September 7, 2018 at 9:56:38 AM UTC-7, Brian wrote:
A Recording engine monitor might be best. As noted engine monitors do tend to increase the heads down time. And looking at the data after the flights might actually be much more useful.

They are quite good at identifying baffling that isn't installed or working right.

They are also very good at helping keep the engine cool, as most experts agree that keeping the CHT's under 400F will extend the life of the engine.

Brian

CHT is the critical measurement, with cooling rate a close second. It's good to give towpilots clear guidelines, and inform towpilots that engine monitor readings will be downloaded and checked, even if they are not....it will make them pay better attention to the engine parameters.

My experience bringing power back to idle after glider release in less than 30 seconds and then not adding power all the way to landing has not been a problem. Our previous engine was well over TBO when replaced, with no issues.
Having more sophisticated engine monitoring might help to run lean of peak to save gas.
Keeping your head outside the cockpit may save you more than gas.

On Friday, September 7, 2018 at 11:10:08 PM UTC-4, wrote:
My experience bringing power back to idle after glider release in less than 30 seconds and then not adding power all the way to landing has not been a problem. Our previous engine was well over TBO when replaced, with no issues.
Having more sophisticated engine monitoring might help to run lean of peak to save gas.
Keeping your head outside the cockpit may save you more than gas.

What kind of airplane?
Your experience certainly differs from my 40 years of running towplanes.
UH

On Saturday, September 8, 2018 at 2:42:00 PM UTC-5, wrote:
On Friday, September 7, 2018 at 11:10:08 PM UTC-4, wrote:
My experience bringing power back to idle after glider release in less than 30 seconds and then not adding power all the way to landing has not been a problem. Our previous engine was well over TBO when replaced, with no issues.
Having more sophisticated engine monitoring might help to run lean of peak to save gas.
Keeping your head outside the cockpit may save you more than gas.

What kind of airplane?
Your experience certainly differs from my 40 years of running towplanes.
UH

UH, do you think recording engine parameters and analyzing them post flight might be worth the effort?

I do wonder if our standard procedure is deficient, maybe analyzing engine parameters would reveal a bad procedure (or a tow pilot that doesn't follow a good procedure). And it would gather hard data that might show, as Dan suggests, that shock cooling is a myth....

Our procedure is to speed up to 100-110 mph put a notch of flaps down and throttle back to 2200 RPM immediately after release, descend/spiral down while reducing RPM by 100 every 10 seconds, until we get to 1500, then we are free to go to any speed/RPM. Sometimes we sideslip, but not always. Please critique!

Maybe we ought to start a new thread on cooldown techniques....

Cheers,
Jim

The Airforce Cadets Pawnee in Warwick Queensland Australia has just had a new engine and new engine monitoring system installed. If you pm me or email me I can get you in contact with the pilot who organised and is flying it.

Justin

Originally Posted by

Hey, gang,

Soon we will be putting an overhauled engine on our Pawnee, and I am wondering if anyone has had experience with or has comments on engine monitoring systems on towplanes.

I am thinking a basic system with all 6 cylinders CHT (and EGT?) monitored, a shock cooling warning system, and data logging. Would monitoring other parameters be useful, also? If so, what parameters (adding sensors adds up $$$)?

Is such a system useful and helpful for our type of flight duty cycle (e.g., towing)? Do the shock cooling warning systems work for our very unique type of operations (I guess they are just an alarm if the rate of CHT drop exceeds a set value?)? Is the data logging useful for monitoring/predicting engine health and life? Am I overthinking/overkilling this issue?????

Thanks,
Jim