Vev

As for AVGAS 100 without tetra-ethyl lead to get it's rating up...must be chockers with aromatics and hence more of a problem than 98 for any rubber/plastic stuff I would have thought. Unless...the refinery IS adding pure toluene or xylenes to bump 98 up...hmmm.

Avgas is made from isooctane and has practically no aromatics at all ... it is highly unlikely to cause a problem to plastics/rubber etc.

 

Cheers

 

Vev

 

 

Why would you want to get an RAAus cert. to fly a helicopter of any sort. Rather than a PPL(H)?What would be the advantage?

Hi Yenn,

 

May be a reduced medical requirement?

 

Cheers

 

Vev

 

 

That's Vev Not Nev. I'm a foundation member of the keep away from crazy palm trees club. Nev

Just recently I got a chance to get a couple of hours in an R22 and had a ball ... I need count my pennies for more time.

 

Cheers

 

Vev

 

 

Asked a CASA guy about this last year, he vowed it would absolutely not happen on safety grounds.Guess it wouldn't help the RaAus fatality record any....

Was CASA saying that RAA pilots can't be trained to fly helicopters safely?

 

I wonder what the French experience is ???

 

Cheers

 

Vev

 

 

As long as you don't turn the engine off ...

Very funny Dave!

 

Serious question though, as I heard there were some people unable, or had great difficulty, in renewing their registration after the technical cleansing exercise of the files.

 

I would hate to think someone would go to a lot of work in designing a glider for RAA pilots to learn that the RAA say are out of scope.

 

Hopefully someone here with more knowledge on this topic will know for sure?

 

Cheers

 

Vev

 

 

I am wanting feed back on what type of glider would interested you.

1 a performance glider 13.5 m class self launch,single seat.35-38-1 glide

 

2 simple car roof rack for transport glider 10-12m self launch. Light 20-25-1 glide

 

3 Motor touring glider 2 place.26-30-1

 

4 foot launch glider

 

would be cheap as a plan and parts to build ,or built.

Question for you.... Are gliders or motor gliders permissible under RAA aircraft categories???

 

Cheers

 

Vev

 

 

Well done Dave ... wonderful effort on so many levels.

 

Cheers

 

Vev

 

 

The 152 rates are lower at Tyabb and you'll get more airtime as there's no taxi time to speak of... If you fly their new 162's, which are a cheaper hire rate than the 152, you can get both your GA and RAA completed at the same time.

 

Cheers

 

Vev

 

 

Hopefully they have improved the intake fuel distribution ... it will be interesting to see if this engine mod will have a better EGT spread?

 

If it this has improved distribution, it may go a long way to stopping the thru bolt issue owing to lean mixtures and detonation, albeit this is mostly a 4 cylinder issue.

 

Cheers

 

Vev

 

 

A very frustrating situation ....

 

If someone was taking your fuel it would be unlikely they would take your fuel cap too ... albeit not impossible.

 

Hopefully the repairer has left it sitting on a bench... he may want to reflect on making good your inconvenience and improving his maintenance process.

 

On the other hand, if it has fallen off in flight I would be concerned about the design of the caps and checking the locking mechanism for damage??

 

Cheers

 

Vev

 

 

Hi Deadstick,

 

Does the plenum chamber split or is the intake tubes a push fit with an o'ring?

 

Cheers

 

Vev

 

 

I heard Rod Stiff say 2 years ago at Natfly he was working on this designed and referred to the CriCri to describe it ... if nothing else, he puts his money where is month is and built it.

 

I also recall him saying that it would fly on one engine, albeit it that was said before it was built!

 

Cheers

 

Vev

 

 

With 160hp from 2 x 4 cylinder engine this will give it some spectacular climb performance?

 

 

Interesting to read that oil changes have increased to 25hrs, which I think is a good thing!

 

Cheers

 

Vev

 

 

Lots of interesting info here from Jab

 

http://www.jabiru.net.au/images/jaba/Jaba%20Chat%20April%202013.pdf

 

Cheers

 

Vev

 

 

Why does my battery charger asks me if my battery is a Gel or Lead Acid? Whats the difference in charging these batteries?

 

Cheers

 

Vev

 

 

Wx being kind this weekend, I hope to be there in my old girl, which is RAA reg and a AAAA member ... we are always made to feel very welcome .

 

Cheers

 

Vev

 

 

Got back today after a great few days at Natfly, I took the long way home and spent another day flying around northern Vic in my old Ercoupe .. Lots of great ac to look at and many interesting people to talk to.

 

I was ramped checked on arrival by 4 CASA people who were friendly and made it clear it was an educational exercise. They found two small issues but no big deal. They did accept my Ozrunways nav and back up with paper charts, although didn't like me air printing my track off my iPad. They also informed me I can use a mini iPad as a primary nav tool with either mini or full size iPad as a back up.

 

Attended a number of the forums, including he RAA GM. I listen to all that spoke from the board ... I particularly thought the Rat, who in my view, made a lot of sense. He (Rat) has not only put some positive tension into the organisation but appears to be developing the pathway to build a more sustainable organisation. There is a way to go before things are put right but I do believe they have stopped the free fall. I believe the board is reacting and good people like the Rat need our support to continue to show the way.

 

Also attended the dinner, which was utterly boring .. It felt like a smoko night at the local footy club. One day they might learn to stop patting each other on the back and do something entertaining .. I think this is the last RAA dinner I will ever attend unless they change the format... I'd rather stay on the AD and watch videos on the back wall of a hangar with my mates.

 

I managed to catch up with a few friends on this forum and also met a few new in person for the first time .. Always fun to put a face to a name and talk about planes.

 

Cheers

 

Vev

 

 

Hang about, doesnt Jabs use Automotive valves and lifters??You could agure the incoreect oil is used.

From a 5 litre Holden for instance???

 

regards Bruce

Hi Bruce,

 

Are Jabiru experiencing cam and lifter wear?

 

I think there's good protection in the currently recommended aero oils.

 

I know trials have been conducted over the past 3 or so years to test an automotive formulation in Jabs by a major oil Co... there is still a lot to be considered as this is not without risk in terms of combustion chamber deposits. I think there is already enough evidence that detonation can be fatal to these engines ... adding a potential new detonation trigger will be a major concern for those conducting the trials.

 

I'm sure Nev can answer this better ... aero air cooled engines burn engine oil owing to their larger piston clearances, that is, larger clearances than water cooled automotive engines. Automotive lubes have additives that can leave deposits on the piston crown that can cause pre-ignition and detonation.

 

Time will tell if automotive lubes will work in Jab engines .... however for now, let the guys with the big cheque books take the risks ... I think sticking with the recommended products is the safest bet for you and me.

 

Cheers

 

Vev

 

 

Goodaye allThere is something that has not been mentioned, the oil companys have removing the zinc in oils for many years.

 

This reduces the shear properties of the oil and wears cams and valve stem quicker to the point wear they can fail after a few hours.

 

Zinc in autmotive oil had to be reduced due to the catalytic convertor getting gummed up, l should see that aero oils have not been reduced either.

 

PS a tip for car owners Penrite mineral oils still have a high Zinc content.

 

regards Bruce

Hi Bruce,

 

Just a couple of points if I may:

 

Zinc has been replaced with a new Zinc technology .. Mostly known as HyperZDP, which maintaines cat life and provides all the boundary lubrication protection needed to protect cams, followers and more.

 

There is no Matalic Additives, including Zinc (ZDDP) in aero engine oils ... They use a different technology.

 

Cheers

 

Vev

 

 

Here's another one for you and am keen to know where the major difference lies in determining what design characteristics are to deem it designed to

use Ashless Dispersant aviation piston engine oils such as AeroShell W Oils, Used in air cooled Teledyne Continental Motors,Textron Lycoming

 

and Jabiru engines.?

Ashless really mean non-metallic detergent ... detergents plate out on surfaces and stop particulates sticking to them... it doesn't really clean like you would think of dish washing liquid does. The metallic additives use to leave residues that could cause pre-ignition, I've really got no practical experience with this as they are simply not used these days in aero engines you mentioned and therefore not seen. Dispersants, in simple terms, envelopes particulates to stop them sicking together and holds them in suspension to get caught in the filter.

 

Cheers

 

Vev

 

 

Hi Camel,

 

Yes was having a graze...

 

There is lots of complexity in your questions but I'll just try and hit the high points if thats ok?

 

Why not use a synthetic lighter viscosity multi-grade oil in jab engines disregarding legal and manufacturers recommendations ?

 

I really don’t see an advantage in a lower viscosity in relation to its lubrication protection in a Jab engine. 15w is the equivalent to a SAE 15 @ 40 deg c (100 degF) and the “w” stands for winter and has a pour point at -32 deg. The 50 is the equivalent of a SAE 50 @ 100 deg c (212 f). All of this gives excellent start up protection with a lower vis and good film strength (this is hydrodynamic film that separates the surfaces) with the higher (SAE 50) during normal operation temps. Btw, Aeroshell is already a semi-synthetic. If you lower the vis you will get less internal resistance (low viscos drag) but could compromise film strength and potentially rupture the oil film and have metal to metal contact. In this senario you are completely reliant on the additive chemistry to protect the surfaces.. much better to use a physical layer of oil to protect the engine. In terms of Syn lubes ... these are good but I prefere the good old minerals with a blend of semi-syn as these have much better clean properties as well as keep the contaminates in suspension to be caught in the filter.

 

What effect on oil does lead content have on oil and how long does it take to have effect. ?

 

Automotive Lubricants are supposed to have backward compatibility and there are some obscure GM engine test that use to measure lead contamination performance. However these days any lead in the fuel will quickly damage many engine sensors and its not really a consideration. In terms of aero engines and Aeroshell as an example, it will tolerate lead contamination but it will plate out around the engine over time and turn into sludge if left too long. All combustion contaminates (including lead) will cause oxidation, causing the lube to chemically break down. Changing the oil often (ie 25hrs) is a good way to keep things under control. Just as a side issue.. synthetics are less capable (owing to lower solvency or aromatics content) than mineral or, to a lesser extent, semi-syn lubes in terms of managing lead.

 

What effect do additives such as "Moly" have on oil other than friction modification ?

 

Most moly particulates are quite big (1 – 100 um) and will just get caught in the filter. Personally, I’m no fan of MoS2 in engine lubes, I know others will argue differently.

 

A high viscosity oil in an engine that should be using a lower viscosity oil, would this cause heat in the engine trying to compress this oil, eg bypass and close tolerences, ?

 

Using to higher viscosity will potentially cause an increase in temp owing to high shear … it is sort of like the oil having its own internal resistance to flow where stationary molecules and high speed molecules interface at a shear point and generate heat. What’s more, a higher viscosity lubes doesn't transfer heat as well and not as effective as a lower vis.

 

Would excessive wear be likely due to a high viscosity oil unable to freely move into areas of small tolerance to adequately lubricate ?

 

Yes particularly at start up when the oil is thick and slow to get around the engine. However, more often this is seen when viscosity get too high in gear boxes you get “channeling” when the oil is too thick to recover onto the surfaces and runs dry.

 

My motive for asking is related to something I am aware of and want scientific facts from an oil man (industrial chemist) to verify or discredit.

 

I'm a motor mechanic, probably won't change much for me,

 

Hope this helps? Cheers Vev

 

 

It refers to an older flow spec. It used to be called 100 seconds. (of time to flow a quantity of oil at a specified temp through a calibrated hole). Viscosity is flow resistance. Nev

Correct Nev .... it's called Saybolt Universal Seconds (SUS) ... it was 100 sec @ 210 deg F to flow through a calibrated orifice ... this basically said the viscosity is getting close to the top end of the viscosity range for a SAE 50 grade base oil.

 

Cheers

 

Vev

 

 

Fantastic Ian ... great stuff

 

Cheers

 

Vev