Vev

Hi Bob,

Sorry to hear about your engine failure but thank you for taking the time to share this info.

At what stage in the flight (climb/cruise/final?) did the engine fail and how long had it been in the air? I’m also interested to know if you have had high/low ground and flight temperatures and if/when this happens.

I think that Walter’s point re “uneven thermal expansion” is quite plausible when you consider the different coefficient of expansion and different thermal conductivity of the engine materials… I wouldn’t be surprised if this is part of the failure mechanism.

However for all our speculation here, it will be interesting to hear Jabiru’s thoughts on the reasons for the failure and what is their recommendation is in terms rectification and prevention.

Cheers

Jack

Hi Jack,

Welcome aboard ... sounds like you will have a lot to contribute.

Cheers

Jack

Completely agree with Nev’s assertions re oil temp .. if too low (< 80 deg c) you run the risk of not flashing off free water and causing corrosion problems.. alternatively temp spikes up to 100 deg c in the sump is not going to harm things either.

Base oils normally won’t begin to thermally crack until temps > 160 – 180 deg c, however consistent elevated temps or short excursions into extreme temps will produce a greater likelihood of oxidation and eventual break down in the base oil and additive system. Once oxidation starts it’s like a cancer that will generate a molecular auto decomposition of the hydrocarbon chain … in simple terms the oil is cooked and engine damage is assured to follow!

Outside of thermal breakdown, maintaining lubes within the right temp range also assists in the lubricant performance in terms of viscosity and hydrodynamic lubrication as well as the additive system to support anti-wear and dispersants.

The moral of the story … it’s a bit like the Three Bears … not too hot, not too cold but just right.

Cheers

Jack

Not sure if this helps but here's a link?

Cowl Plugs from Aircraft Spruce

Cheers

Jack

G’day Rocketdriver,

Nice to hear a positive story … I’ve known Brent for a couple of years and he is always ready to promote flying and help out anyone in need. Glad you enjoyed your fly with him … I sure you will enjoy the guys down at the Tooradin Flying School too... welcome back to the big blue.

Cheers

Jack

G'day Turboplanner,

Re exhaust bandage.

I had spoken with a number of experts as well as had quite a bit of feedback from a few on this forum before I tried it. In addition to this I ran an oil condition monitoring programme and did an oil test every hour to track the impact for 50 hrs to look for wear metals and oxidation levels ... I also shared the results with a couple of very good engineers that have a lot of experiance in this area. I persoanlly didn't run temp probs in the engine compartment but a lame in SA did and reported the temp reductions on this site.

It's now been in place for a bit over 200hrs and i'm still doing condition monitoring ever 25 hrs and not seeing anything to be concerned about, however I am enjoying a lower engine bay temp which is kinder to all things electric.

Btw... I also reported the mode to the RAA to put it on the record.

As I said ... If i had to pick one performance improvement I would do the adjustable prop hands down.

Cheers

Jack

Steve,

I did a couple of simple things to my 160 to get it to perform a bit better.

1. I fitted a ground adjustable prop and made sure I could get 2900 rpm static run up and 3000 on take off and climb. Letting the engine rev really makes a difference.

2. Fitted NGK Iridum plugs .. these seem to give me may be 25 rpm more on static.

3. I wraped the exhaust in bandage .. not completely sure if this made a huge difference but it did helped keep the temps down.

4. Fitted the recommended richer jets in the carby

In my experiance the adjustable prop is the go .... the trick is to let the engine rev and develop the HP. You hold higher revs on cruise but the Jab Engine guys tell you that's a good thing.

Cheers

Jack

The Jab 6 cyclinder (120hp) is 178 lb and the Honda 199 lb ... the Jab is close enough to 10kg lighter.

Cheers

Jack

Looks interesting ... great price at US$12k

Cheers

Jack

Yes you are right, but your take off and climb rpm will always be lower than max rpm in S&L flight.... in S&L flt you will see the engine speed increase if you held full power.

I have a varible pitch prop on my 160 and pull 2900 in static mode, 3000.3050 rpm in climb and 3300 in S&L flight at full power. I tend to cruise around 3000/3100 @ 100/105 knts.

Cheers

Jack

Full Power (3175) 28.5

In terms of max RPM, I beleive this to be 3300 RPM for the 2200/4 engine. The guys at Jab always tell you not to baby the engine and drive it hard, therefore I really wouldn't think 3050 rpm as being too hard on the engine.

Cheers

Jack

yes .. sorry guys I had stuffed up that part number ... it is in fact DR9EIX.

By the way, on the weekend I took a look at my HT plug leads and noticed some rubbing between the leads where they cross over between the distributors. I was wondering, if this was left unchecked could this be the source of shorting between the leads and be a cause for plug fouling? Could it also explain why one would still experiance a missfire on both mags?

Just a thought?

Cheers

Jack

Hi Pud,

I put the Iridium NGK XI9EAR in my Jab and have had them in there 125 hrs ... had a look at them on the weekend when I did my 25hr oil change and they still look perfect. The guys at Jab but me onto them and said they use them in their own aircraft.

Cheers

Jack

Rocketdriver,

Many thanks this ... it makes sense and it does help.

Cheers

Jack

Tomo,

Interesting comment about a using a little flap on the Jab.

Myth or not???

A couple of years ago I went to the Cowra fly-in and spoke with the guys from Jabiru and was told that when the 160 is fully loaded just add 1 or 2 deg of flap and it will pick up the tail and increase air speed. I experimented with this and found I picked up 2-3 knots in S&L flight. The Jabiru guys said when the flaps a fully retracted the flaps are in a negative position.

Cheers

Jack

Thanks for the feedback and info on my question guys.... always something new to learn everyday!

Cheers

Jack

And don't rely on the VSI to give you best glide. It WILL give you minimum sink. Best glide and minimum sink are two totally different thing. If you are flying for minimum sink, you may not make your chosen field.

I think I understand what you have said ..... but can you explain this to me in a little more detail and what this means in a practical sense with situations/examples?

Cheers

Jack

Hi Sue,

May be not much help to you in Childers, but something to keep in mind (if Mogas is approved for your engine) and you are having vapour lock problems with Mogas in remote hot areas. Opal fuel is a Mogas 91 RON product but has basically the same chemical volatility profile as Avgas without the lead.

The low volatility is why it can’t be used for petrol sniffing and was introduced by the Government in remote areas where they had a problems.

However do make sure that Mogas is approved for your aircraft and do your own research (check with oil companies) and satisfy yourself about the suitability.

Cheers

Jack

Hi Sue,

Thanks for the feedback … I can relate to your problems of accessing avgas through personal experience. Over the past few months there have been a number of fuels storage facilities removed around the country. Shell walked in a few months ago and dropped a bomb shell on our club and said we can either buy the facility or they will rip it out. Fortunately we managed to negotiate an acceptable deal and bought the tank and pump set up… we also have a new supplier who has given us a better deal too.

Your new engine sounds like an interesting project and look forward to hearing how thing progress.... good luck with it all.

Cheers

Jack

I’m looking to take my Jab down south to Tassie to visit my daughter (she moved down there from Melb) and was wondering what airfield/s are available around Cygnet? The closest I can see is Sandfly but I was hoping to find something closer …. Any suggestions?

Cheers

Jack

Hi Kaz,

Completely agree with your comments about wax – cloud point of diesel fuels, in fact it’s more complicated as it varies geographically as well as seasonally.

What caught my attention was in the manufactures spec sheet, it said “Diesel/Jet A1” .. of cause Jet A1 won’t have the same issues and think this would be a better choice to avoid waxing.

Basscheffers,

The problem is Diesel Fuels vary considerably between seasons and region … to give you an example .. if you fill with Diesel, lets say March in Townsville, you will find the cloud point to be 11 deg C … if you then fly to south to Brisbane the max spec for cloud point is 3 deg C for the same period. If you delayed your flight until April the max cloud point is 0 deg C for Brisbane. Therefore the risk is about purchasing diesel fuels in warmer climate and flying into cooler geography/seasons as you may be at risk of fuel turning into wax in your fuel lines … not to mention the risk of fly high and cooling things off.

Jet A1 has a very low cloud point and should never be an issue with the type of flying we do.

Cheers

Jack

Hi Sue,

Sounds like a very interesting engine?

Whilst I know it's a diesel, but what fuel is recommended by the manufacture? The reason I ask, is I would have huge concerns about the use of diesel fuels in Australia if diesel fuel was being considered.

Cheers

Jack

Hi John,

This is not the simplest of questions but there is an answer.

Castrol’s Magnatec is a very high quality engine oil which uses excellent base oils and additives to make it one of the best engine lubes on the market. Whilst its specifications including the US API specs and the European ACEA specs, which suggest it has backward compatibility and performance with earlier engine oils that included engine sequence tests on leaded fuels.. . however these tests are now somewhat obscure today … never the less it does indicate it is compatible with leaded fuels (albeit at lower levels of lead concentration than Avgas LL) and will most likely do a good job.

The other issue to consider is your engine (Subaru??) was designed to use automotive style lubricants which have a different additive chemistry to ashless aviation lubes… therefore ashless aviation formulations are not really the best selection in my view.

Fortunately for you, Shell has recently developed the Aero Shell Sport 4, which carries most of the recognised automotive specs, including the Japanese JASO MA motorcycle spec for wet clutches (important for Rotax) along with excellent capability to manage Avgas LL. I would think this to be a better selection for your purposes…. it provides the correct chemistry for automotive engineering and can tolerate the lead in the fuel at Avgas concentrations.

However please be mindful this product is not suitable for Jab engines as they need an ashless formulation which is derived from a different chemical additive system.

Why don’t you give Shell’s technical help line a call and talk it over with them to satisfy yourself of the technical merits.

Cheers

Jack

Methusala (Don),

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Happy for you to also have a healthy level of scepticism along with a dash conspiracy theory for good measure…. but have you actually read the White Paper???

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Everything I have read tells me that the RAA model has support by the Minister and should be considered for replication (not the RAA but the model) to try and advance aviation. The paper recognises that the RAA (and others) have done a good job in self administration (including safety) to develop aviation.

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In my view, telling CASA “put up or shut up” and suggest they don’t take up some sort of leading safety overview is nonsensical in the extreme… one of CASA’s lawful primary roles is to manage safety (albeit they could improve) but if RAA was found to be neglectfully wanting in safety by CASA it must be called to account.

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You say “fight for our lives” … in contrast to you, I say, “we are we are poised for growth”.

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In a war you take sides and talk about "them and us" … we are not at war and there’s much more to be gained through constructive collaboration across all stakeholder be it the Government, CASA, the community or Mr McCormick.

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Cheers

Jack

Hi James,

There is a significant difference in the chemical additive systems used in Aero Engine Lubes to create an ashless formulation. Automotive lubes (including air cooled 4 stroke motorcycle oils) use a metallic based anti wear additive system (often zinc) that isn’t acceptable to most aero engine manufactures owing to the potential for deposit formation during the combustion process. Jabiru doesn’t support automotive type lube systems as they do not meet their requirements.

By the way … You asked about using semi – synthetics … the recommended Shell 15W-50 is in fact a semi – synthetic by chemical definition.

From my point of view, without thousands of hours testing both on a dyno and field work with the OEM I wouldn’t do anything else other than stick with recommended lubes…. There are way too many things to go wrong without testing properly. Besides, I really don’t think you will achieve any better result than using the recommended lube.

The absolute best thing to do re lubrication: change your oil frequently, use quality filters and don’t allow the oil to get too hot and keep it clean from dust and contamination.

Cheers

Jack