CASA - Draft Proposal for Jabiru Aircraft

[Teckair]

Jabs letter , all true, fuel aint what it used to be . We should have mtow of 700 kg, so engines could be run on lpg mutch higher octane

Nah should be 700,000 kg so we can have multiple jet engines.

 

 

[motzartmerv]

A few types (with rotax's) comes stock with purpose built winter Oil cooler covers that you screw into place for winter otherwise you wont ever achieve 50 deg's before takeoff.

 

 

[jetjr]

I use the same on Jabiru 3300, needs it in winter or it never warms up, summer can run with smaller block

 

In cruise oil struggles to run above 80

 

Interesting that removing the cooler block upsets airflow in ducts and they run a bit hotter

 

 

[kaz3g]

The Auster HAS to be VH, Kaz. The two seater re-engined with a "FLAT motor is almost a Cub in concept. If you run a wooden prop and remove the starter and replace the generator with a small alternator and use a small battery you save a heap of weight. You can keep an Auster type of aircraft in the air forever. Flyable I mean. .Nev

Yes, Nev

 

I couldn't resist the comparison because, as you say, the Auster can fly "forever"... No SIDS! But only a few of them can meet RA limitations.

 

You can see the common aetiology of Auster and Super Cub when you look at mine, and you would be surprised at the number of fliers who misidentify it despite the side-by-side seating and the much greater wingspan.

 

They both cruise at 100 KN, and both carry around the same load, but my stall speed is 11 KN slower than the Cub.

 

Kaz

 

 

[facthunter]

OK Maj, Are you prepared to back that statement with your own money.? It has been around for years but if you think about it is pretty much relying on a bit of magic. The engine will probably go for a while at reduced power, but you can't rely on it as recently one didn't keep going and the pilot is a very much clued up operator. The fact they run too cool often, doesn't mean running with no coolant can be safe. Thinking it WILL keep going, can get you into a bad situation. Better to land and correct the problem. They do after all often run quite hot with Evan's waterless coolant, in some installations. Nev

 

 

[skeptic36]

Better to land and correct the problem.

Shirley, that goes without saying. The point is it will get you to a place where you can land safely assuming you are not half way to New Zealand when it happens that is.

 

 

[facthunter]

My name isn't Shirley.. so that hasn't impressed me.. Perhaps you mean surely.. Why does it go without saying? . ANYBODY reads these posts. and the word has been out there that the engines will be OK without coolant. I know that isn't so. Does Rotax say it will go nearly half way to NZ.?. People need to be able to have the facts to go on. Of course the motor is a bit less sensitive than some others. but it ain't made of magic. Nev

 

 

[kaz3g]

http://www.jabiru.net.au/images/JSL014-1_Jabiru_Cylinder_Head_Inspection_4.pdf

[Keenaviator]

https://www.youtube.com/watch?v=0A5t5_O8hdA

[skeptic36]

Why does it go without saying? . ANYBODY reads these posts. and the word has been out there that the engines will be OK without coolant. Nev

O.K you can look after those poor intellectually challenged people who are unaware there water cooled engine is going to need attention ASAP. I will point out to the others that the Rotax 912 without coolant can be used to aid there efforts to get to a safe landing area before such attention becomes mandatory, and we will leave it at that

 

 

[dazza 38]

http://www.jabiru.net.au/images/JSL014-1_Jabiru_Cylinder_Head_Inspection_4.pdf

Well after reading all of this, if the operator runs the engine within a narrow temperature band and checks this, checks that, removes this and removes that every 5 minutes. The engine should nearly be as reliable as 912 that hasn't been touched apart from the standard maintenance. Well done Jabiru

 

 

[motzartmerv]

Define new? The latest offerings? Or the several so Called upgrades over the last several years. Our latest thru bolt failure was with bolts fitted by the factory in a top end. Surely the FACTORY are aware of their own SB's?

 

Any idea, when confronted with 'experiment or observational data that contradicts' the hypothesis, means its WRONG, regardless of how good we think the idea is.

 

I forget which scientist said that, but its been a core principle of scientific endeavour ever since. What im saying deb, is that its nice idea, that we can blame not fitment of latest spec bolts, but unfortunaltey, the evidence doesn't support it. Time to move on and find ANOTHER idea.

 

Eventually, once all the "external" ideas are proven wrong, maybe. Just maybe, we might actually look at the design itself...Just sayin..We can live in hope.

 

 

[alf jessup]

OK Maj, Are you prepared to back that statement with your own money.? It has been around for years but if you think about it is pretty much relying on a bit of magic. The engine will probably go for a while at reduced power, but you can't rely on it as recently one didn't keep going and the pilot is a very much clued up operator. The fact they run too cool often, doesn't mean running with no coolant can be safe. Thinking it WILL keep going, can get you into a bad situation. Better to land and correct the problem. They do after all often run quite hot with Evan's waterless coolant, in some installations. Nev

Actually Nev,

 

I wouldn't say run quite hot, they actually run closer to the design parameters running with Evans NPG waterless coolant, when I went with Evans in my Tecnam as with my trike the water temp went up to about 9o deg compared to 60 with the 50/50 glycol, Rotax recommends 90 deg the normal operating temperature, most of them run way too cool.

 

Out of coolant well can't answer that, but if need be I would run it until it stopped to get me out of a bad terrain situation if I got myself in to that situation.

 

I have flown out of Yarrawonga on a 37 deg day at almost max gross weight full song to 8500ft to cross the divide and the coolant temp never got out of the green as the same with the oil temp, mind you they were both close to the top of the green but never the less they never got out of it and that was with the Evans in it.

 

Alf

 

 

[motzartmerv]

I dunno, but ive had a Gazelle dump all its coolant (most of which came in the cockpit and over the windscreen)

 

We got home no problems. Reduced power as per the POH and nursed it home. CHT actually went cold due to the sensor not being wet I recall. But this wouldn't have been accurate obviously.

 

No damage was caused, and the engine is still going. 7 years later.

 

Certainly wouldnt recommend running or continuing flight tho, in our circumstance we had no real other alternative.

 

The engine couldn't be used normally, ie, no go around was available, we couldn't gain altitude, so technically, it was still a forced landing and if the Rotax loses its coolant, you need to fly it in exactly the same way as you would in a forced landing. The only benefit is that you may be able to fly it to the forced landing area of your choice..!/2 an hour away..

 

 

[jakej]

As I don't have the time to read through the now 82 pages on this subject, has there been mention of why a lot of Jabby's have only 2 x CHT probes fitted ?

 

Jake J

 

 

[Keenaviator]

As I don't have the time to read through the now 82 pages on this subject, has there been mention of why a lot of Jabby's have only 2 x CHT probes fitted ?Jake J

I think the majority of Jabs would have no more than one CHT probe fitted.

 

 

[01rmb]

The only people trying to make the Jabiru engine the same as a Rotax is CASA and a few people on this forum. The actual owners are happy to have an engine that costs 2/3 the price with parts 1/5 the price to get a lower cost alternative to the other engines that are available. If the engine requires some additional inspection and maybe extra maintenance (if operational conditions warrant them) to achieve good reliability and fewer engine failures then then that is a good outcome but people still are not satisfied.

 

Some people have been getting extremely poor reliability whilst others have been doing well - You can't ignore variables such as temperature, training, fuel, operational handling, inspection or maintenance from this equation. This bulletin from Jabiru seeks to address some of those variables that are known to cause more problems and addresses it with increased inspection. It would be ideal if the engines can handle all sorts of varied and poor conditions and handling - Jabiru are still trying to improve the engine and make it more robust and CAMit have done a lot of work in that area as well. My desire is that better knowledge leads to better parts and maybe improved design that will yield increased reliability and ability to handle a wider range of conditions - but still you can't make it idiot proof since idiots are improving all the time.

 

And yes - better engine monitoring seems a key. So how do you get CHT and EGT on a standard steam non glass cockpit? I have been looking at the Electronics International CGR-30 Primary Engine Monitoring System or Dynon EMS-D10 Engine Monitoring System. You could just remove all the temp/pressure/voltage gauges with one of these and get far better monitoring with a fuel computer to boot. The EI one is particularly neat since you can just slot in place of the tacho. It would need Jabiru though to have this as an option or authorise these in a standard 24 registration configuration. Comes at a price though.

 

 

[motzartmerv]

but still you can't make it idiot proof since idiots are improving all the time.

yea, dam those idiots that keep having problems hey..

 

And yes - better engine monitoring seems a key. .

How? How does it make a failure less likely if you have a guage telling you its running hot? Ive had a 6 cyl with full EGT and CHT monitoring. It showed no ver temp events UNTIL one day it DID..And grenaded.. On Crosswind.

 

You can send the data to Jab and they will just say "no explanation" can be found for the over temp event. Helpfull. Now wheres ya cheque book...?

 

 

[dazza 38]

The aircraft needs CHT and EGT temp monitoring on ever cylinder as mention above because sone operators are find massive temp differences between each cylinder. But also students must be diciplined the monitor the engine monitoring as well as it appears to only take one over heat even to cause damage

 

PS- I was typing this as Merv was typing the above. After reading his post, maybe the temp monitoring isn't going to help as much as I thought. If the donk lets got straight after the event.

 

 

[motzartmerv]

Yea, monitoring is a must. But my point is, what good is 1 or 6 when thermal runaway, or detonation etc is the cause?

 

All we can do is operate INSIDE the specs, thats all we can do.

 

 

[Guest Maj Millard]

Nev, Since I posted earlier about loss of coolant on the 912, I have recieved two private Emails from people in this country who have suffered coolant loss, and still made it to their destination. Add Motzs' Gazelle example and that makes three. I Also know of one in a Storch out bush and he made it home fine also without drama, so that's four. All four engines as far as I know suffered no damage and all are still operating fine.

 

Obviously if you have lost the coolant side of things you would operate at a reduced capability and closely monitor the oil temp, however all have said that it ran high, but still well within range.

 

This is a capability that adds to the Rotaxs good name for reliability, and being able to continue on after a significant fluid loss is a good capability to have. Obviously the over- riding factor is good maintenance and regular checking of all hoses, and adhering to Rotaxs recommended five year hose replacement should make coolant loss a rare occurrence.

 

Bit like having sheared the cold side of a turbo charger on a Lycoming. You've lost some power but the engine will still run ok and get you back to base.

 

Unfortunatly though, if you suck an exhaust valve or shear the flywheel bolts on your engine, there is only one place you are going.

 

 

[bexrbetter]

My name isn't Shirley.. so that hasn't impressed me..

"Shirley" is a very famous quote from a very funny aviation movie and one of the funniest movies of all time. The term is now often used as shorthand for 'surely you can't be serious'.

 

 

[motzartmerv]

I am serious, and dont call me Shirley.

 

 

[flyvulcan]

A potentially good engine monitoring system (EMS) for the Jab is one offered by MGL avionics. I have recently bought one for an engine project that I have and so far it is working well.

 

It offers monitoring and alerting of a total of 12 CHT/EGT parameters so will monitor all of the Jab3300 requirements (6 x EGTs plus 6 x CHTs).

 

The EMS, plus it's required RDAC (Remote Data Acquisition Computer) cost me around USD1300. Alternatively, there is their mini EFIS which has all the functions of the EMS, but with full flight instrumentation as well. This is around $400 more than the EMS.

 

They fit into a standard 3.1/8" instrument hole.

 

http://www.mglavionics.com/html/xtreme_efis.html

 

is a link for the EFIS. The EMS is on the same site.

 

This EMS/EFIS has preset alarms to allow specified parameters to be set and monitored. It means that if any single preset CHT/EGT threshold is reached, the pilot is alerted of the fact, even if they do not have that parameter displayed on their instrument at the time. It also has data recording so engine condition can be monitored and should a failure occur, any trends leading up to the failure can be observed.

 

I have posted this so that Jab owners can see that there are reasonably priced options available to monitor all the parameters required and warn/record any exceedences without actually physically observing the exceedences (don't we look outside the cockpit 90% of the time?).

 

 

[DonRamsay]

. . . The actual owners are happy to have an engine that costs 2/3 the price with parts 1/5 the price to get a lower cost alternative to the other engines that are available. . . .

I seriously doubt that the lower up front cost and cheaper parts would offset the need for so much work over 2,000 hours compared with a Rotax gearbox overhaul. But, even if the Jab, having a particularly good run, proved to be less expensive over 2,000 hours, I would (and have) shelled out for a Rotax for the extra peace of mind that comes with not putting my passengers at as much risk. Not saying a Rotax will never fail in flight, that would be silly but all I can do is work the probabilities. At the moment, sound risk management says to me go with the Rotax.

But, that is not what this thread is meant to be about. It is meant to be about the the unscientific, poor management approach of CASA to the issue of Jabiru engine reliability. And I haven't heard much (anything?) in the way of defence of CASA's approach. Perhaps that's because it is indefensible?