question Best Temperature Instrumentation for Jabiru 2200

[Bell Driver]

Completing Savannah VG restoration. I'd like recommendations for temperature monitoring. Digital or analog? How extensive-- all cylinder CHT and EGT or just CHT on the rear 2 cylinders. Want simple as possible, but not simpler.

[WayneL]

MGL Avionics make some nice gauges.

Have a look at lightflying.com.au

[skippydiesel]

Grown up with steam gauges - easy/intuitive - size & price for all applications. I would recommend coolest (usually front) to hottest (usually rear) monitoring capability. This tells you more than just the worst case (hottest) scenario.

[facthunter]

Sort it out and then just measure the hottest one.. Nev

[Bell Driver]

Last couple short flights, our prototype panel had just airspeed and oil pressure. So a good bit of sorting left . The MGL instruments look really woth considering, though as an old guy, would take some getting used to. Nev thinks the way we do. Previous owner had her loaded up--we want simple.

[facthunter]

You have to decide what you are going to do about a high temp in the air IF it happens. Don't wait till you are at a scary temp . If it's rising too much increase the climb speed and often you get the same Rate of climb at a higher airspeed. All fine if there's nothing in the way. There may be heat responsive paints about still that will indicate you have exceeded a specific temp. You only need to cover a small area to get the indication. Nev

[skippydiesel]

Seems to me its not just about not exceeding a given temperature ,its having the ability to see that there has been a divergence from whatever you call "normal".

Few if any recreational level gauges should be expected to give what you might call an accurate reading (no matter what you pay) - what they will give is a reasonably consistent reading.

Once you have established the acceptable reading on your gauge/system - record it - then monitor for change.

It is the change that might alert you to potential engine trouble(s).

[cosmicray]

I use the MGL TC-3 to monitor EGT and CHT on my Jabiru 3300. It's a good instrument. Easy to read and set up.

[Bruce Tuncks]

My arduino system gives me EGT and CHT on each cylinder to the nearest degree and cost very little. The EGT setup was important in getting the temperature spread right, but after that was achieved it is not really needed anymore. The Jabiru system does not have mixture control so once the thing is set up, there is nothing to use if for.

The setup uses a cheap thermocouple board which cannot cope with common earthing, so it uses a clever relay setup. The relay setup and the arduino program were done by an expert clubmate ( Jab 7252 ) and the whole system works fine and cost about $100. ( thermocouple boards for common earthing cost squillions.. this is a hard won bit of knowledge, at the outset I had no idea there was such a distinction ).

If you are an electronic diy person, let me know and I will help if you want to build your own instrument.

[Bruce Tuncks]

Here's a pic. It is showing the CHT's

[rendrag]

MGL Avionics make some nice gauges.

Have a look at lightflying.com.au

For what’s it worth having been an engineer for all my life, while digital look nice when you are up to your neck in a swamp with crocs all around you can glance at an anologue gauge and note the needle position and can tell if it’s right, but in a bumpy ride you have a problem reading the digital values.

For reading the CHT I have thermistors under 1 spark plug per head which all go to a four way switch before a cable goes onto the gauge then I can just rotate the switch to read all the heads (but tend to leave it on no.4 the hottest)

[Bell Driver]

Aside from cost, I think MGL (Blaze Series) may be the one for us . Easy read, and lots of info./options. Thanks for the thoughts and ideas. Now looking in the sock drawer for money.

[brinykraut]

For what’s it worth having been an engineer for all my life, while digital look nice when you are up to your neck in a swamp with crocs all around you can glance at an anologue gauge and note the needle position and can tell if it’s right, but in a bumpy ride you have a problem reading the digital values.

For reading the CHT I have thermistors under 1 spark plug per head which all go to a four way switch before a cable goes onto the gauge then I can just rotate the switch to read all the heads (but tend to leave it on no.4 the hottest)

 

I feel much the same--using old-school split CHT/EGT gauge with 4-way switch to monitor all, especially #4.

Edited April 25, 2020 by brinykraut

[skippydiesel]

Hi Brinykraut,

 

Interesting instrument/engine control layout.

 

What I see:

2 seat ultralight

Warm weather

In cloud/light rain @ 860 ft (AMSL ?) probably only 500 ft, or less above terrain.

Very low oil temperature - good pressure.

What looks like part of a transever control less frequencies ??

Level/slipping turn @ 75 knots indicated - inclinometer overly sensitive (I have one too)

Engine speed (2500 rpm) indicative of a direct drive engine (Jabiru ?) @ about economy cruise power

Interesting split EGT/CHT - I see your 4 way switch - size & complexity suggests an obsession with engine temps.

Navigation tablet - cant read it very well and I dont recognise the App

Hard wired ELT

What are the two black oblongs (OAT & time?)

Centre engine/ electrical control - recognise all but the "gold" thing top left (Starter??) and the white button bottom right (circuit breaker ?)

[Yenn]

For the Jab engine you can get CHT sensors of two types.

Jab recommend the type that goes between spark plug and head. The other is connected to a fin by a screw.

The under plug type tend to break when you undo and do up the plugs. I have changed to the screw mounted type with no problems.

[cosmicray]

Hey Yenn - when you changed from spark plug to the screw mounted type CHT sensor, did you just change the connector where it attaches to the head or did you install a completely new sensor(s)?

[jetjr]

Jabirus need all cylinders monitored, hottest moves around and you have to watch egt

Cht probes need shielding from air blast , under plug ones are hard to centre and seal and break eventually

Terminal screwed to hole between plugs is the go covered in insulation or metal shield

[Bruce Tuncks]

nice neat panel briny. What does the clinometer do?

[KRviator]

A cheap skid ball by the looks of it.

[Old Koreelah]

A cheap skid ball by the looks of it.

That's not a cheap skid ball!

My teenage kid made mine from with a vinyl tube, ball bearing and two wine corks:

 

[facthunter]

Have to have the right damping in a plane. Too lively leads to hallucinations. Nev

[Yenn]

I put in new sensors, the old ones were damaged by the turning of the plug. They lasted quite a few years, but it was going to happen again.

[Bruce Tuncks]

Thermocouple sensors are just the 2 wires joined together. I used 10mm of 3mm copper tube , poked the bared ends in, and squeezed with pliers. I also included a length of stainless steel safety wire ( 30 cm sticking out both sides) so the sender bit could be tied to a cylinder.

The original Jabiru part was a tagged electrical washer and the thermocouple wires were just crimped into this washer.

Mine have lasted several years now

[Mike Gearon]

That's not a cheap skid ball!

My teenage kid made mine from with a vinyl tube, ball bearing and two wine corks:

 

[ATTACH alt=image.jpeg]52691[/ATTACH]

I like that a lot. Simplicity. What liquid?

[Old Koreelah]

I like that a lot. Simplicity. What liquid?

The tube is filled with air, at atmospheric pressure.