Vev

I'm seriously thinking about importing an (second hand) aircraft from the US and was looking for some good guidance, pitfalls and suggestions before I take the plunge? Also keen to hear about any experience of getting an imported second hand aircraft on the RAA register? Cheers Vev

Hi Rod, I haven't done any oil analysis on Rotax engines that I can recall but have done many many engines over the years. As the Major said, trending is important and needs to be done consistently via the same method each time, it also requires good record keeping i.e. knowing when and how much oil top done etc. You can get a very good feel for the lubricant condition in use as well as the particulates in situ .. this will allow you to start plotting and then predict failure over time... however it really takes a trained tribologist or condition monitoring engineer to interpret the results properly. I know some companies offer the interpretation with their oil analysis kits but I suggest these are about a 30/70 result in terms of usefulness and are more marketing than engineering. Particle analysis will show up problems long before you see chunks in oil filters, although you need to maintain a high frequency sampling programme to do this with any accuracy. I have used oil analysis on my own aircraft to look for precursors to identify potential problems, although I wouldn't recommend you do this owing to the costs ... I'm fortunate to have access to an oil lab and the training to do my own. There are some basic particulate analysis you can do yourself using filter-grams but you really need to know what you are looking at to be of any use. I think the counsel given by Nev is spot on in terms of cost/risk outcomes ... Oil and filters are cheap, change them often and cut open the filter and take a look. Hope this helps? Cheers Vev

Hi Ian, For what it's worth, I put a carbon fibre ground adjustable prop on my 160. When I set it up I focussed on the static RPM to ensure I got a min of 2900, which improved the take-off distance and climb. In summer (that is, when we had summer in Melbourne) I had leaned off the pitch to get a few more revs (about 50 rpm more) which was great on hot days too. Whilst you technically lose a little bit of speed you make this up with a few more cruise revs .... in cruise I pay more attention in keeping the CHT and EGT in the right spot which is an outcome of load and of course fuel flow. The only effective in-flight fuel adjustment is the throttle and you need to have enough load on the engine to get the Bing to run on the finer part of the needle and use more of the main jet. Getting the fuel flowing to keep the engine cool is critical in the Jab and you need to be on top of this if you change the prop pitch. If you use a finer pitch prop at the same cruise RPM as before you will run too lean and over heat the top end. Don at Jab says never to be frightened to fly the Jab like a fighter and get stuck into it, keep the revs up and pour the fuel in.... in my experience I agree with his sentiments. Hope this helps? Cheers Vev

It would be nice to have an engine that doesn’t fail at anytime, however some (not all) of the opinion here seems to be based on old engine and old experience which is unqualified and unsupported with any current data. I think Jabiru is getting it more right than wrong and their current engine is very strong. I believe (support by Jabiru notices) much of the last few engine problems were caused by the lean economy jetting, which had done long term damage to the engine even if only used for a few hours … unfortunately we are still seeing failures today that was caused pre 2007. Some lessons learnt by others around the world, particularly the Africans, showed that if you get the jetting right the engine does run TBO. To simplify the learning, always run your engine EGT under 1250 deg f , which is code for, run your engine rich … if you don’t have EGT’s fitted you have no way of knowing if you are shortening the life of your engine. For what it’s worth, you will also surely shorten the life of any air cooled engine if you run it lean, therefore Jab isn’t on their own. In my experience I have found Jab are quite reasonable when it has come to putting things right and have been very good at providing support and parts free of charge or heavily discounted. Furthermore I know that Jab take engine failures very seriously and do try to deep dive any failures to develop solutions. Cheers Vev

Hi D10, Have Jab given you a reason for the hold up? Have they said anything about the cause of your thru-bolt failure? Cheers Vev

Try this one ... cheers Vev http://www.auf.asn.au/docs/admin/asic-appn.pdf

The latest JabaChat is now on line .... some interesting info contained http://www.jabiru.net.au/Jabachat/Jaba%20Chat%20March%202011.pdf Cheers Vev

Spot on Geoff .... should also be able to get rental car at Frankston too. Chris ... if you decide to fly into Tyabb, PM me and I can fit your jab into my hangar. Cheers Vev

Hi Greg, It certainly sounds like you have an over heating problem, stuck and broken rings is a clear sign of heat in the Jab ... interesting to know what jetting you have in your Bring?? Also useful to have EGT's fitted in the jab as anything over 1250 F is death and jetting is the best way to manage temps. Head crush is common problem if one is too heavy handed on a torque wrench. They really shouldn't be torqued down beyond 20ft lb (as specified in the manual) after the initial 24ft lb assemble torque value.... any more than 20ft lb and you begin to crush the heads. Cheers Vev

Hi DJP As it was explained to me (but i could have it wrong) in terms of drag reduction .. the taper on the end of the wing tip needs to come to sharp point. It doesn't matter if it points up, down or continues on as an extension of the wing... they all reduce the wing tip vortex. The angle of the winglet (up, down or out) has more to do with lift, wing span and structural issues. I'm a bit out of my comfort zone DJP as I'm just repeating what I heard in the lecture at Oshkosh ... I'm sure if anyone can put some meat on this you can. Cheers Vev

Hi GG, I'm sure there will be much more knowledgeable people out there on this subject. However, I attended a seminar at Oshkosh last year on aerodynamic drag and this discussion game up. It was said by the experts, that both the winglet and turned down wing tip do basically the same thing and both reduce drag. They went on to explain a sharp wing tip is the key to lowering drag by reducing wing tip vortex ... how wing tip is positioned is about meeting other design functions and nothing to do with drag reduction. Hopefully some one else can build on this to give you more detail about the theory. Cheers Jack

Spin, Spot on ... I had a good look at Cessna 162 Skycatcher at Oshkosh last year (2010) and they too had added a huge ventral fin along the fuselage which extend to form part of the rudder bottom ... the Cessna sale chap said it was added to assist spin recovery, following some flight test problems. Interesting to note the 162 I looked at had had a significant tail strike.... The Cessna's tail is only about 2 feet off the ground... at least the Jab has a good air gap to support the ventral. Cheers Vev

So pleasing to hear a good end to this story!

The aircraft was flying from the Oaks to Pooncarie with two people on board. The family of the pilot raised the alarm on Friday afternoon when they had not heard from him. http://www.abc.net.au/news/stories/2011/02/05/3130693.htm

This is what was stated in the bulletin by Jab: "fitting a larger ventral fin improves the aircraft’s directional stability – the pilot’s rudder inputs are fewer and smaller in all modes of flight". When I spoke with them this week, they stated there was two reasons 1. Directional stability needed to be improved throughout the flight modes 2. Under server testing, during full power stalls, this modification assisted in spin recovery and provided better authority. Cheers Vev

I’m often amazed at the hostile reaction leveled at Jabiru when they are clearly trying to rectify an issue. In my personal experience, they have always made every attempt to support any problem I have had… I have often received free or heavily discounted parts even though my aircraft is well out of its warrantee period…. I know many manufactures would simply send one to a call centre to chat with some dispassionate person on the other side of the planet. I think we should be proud of what Jab have achieved as an Australian company and recognise their drive to keep on developing and improving. It’s a small family company, not a global conglomerate, who do a fine job that deserves more support … they should be congratulated for listening and offering a solution. Cheers Vev

Talk about bases of fact ... when I spoke with Jab yesterday they informed me they will be paying for parts! You buy the parts on account and then you send back the old bits for a credit. Cheers Vev

Hi Nev, I quite agree ... the idle system and choke do very little in terms of fuel contribution when the butterfly is open ... a mistake often made is to have the idle set too high and the choke system not work on start up as the throttle (butterfly) needs to be all but closed to create the pressure drop to work the choke and idle systems. Again I agree ... float levels are important in terms of mixture control and they need to be checked to ensure they remain constant during routine servicing. The Bing has its subtle characteristic and understanding the different needle and seat compound combos and sizes is important to manage float levels. Interesting observation on the FAA finding ... someone there obviously doesn't understand how a CV carby works! Cheers Vev

Nev, I guess it has the potential to very marginally lean the mixture but it's small beer, it more about improving the atomisation of the fuel ... never the less it still needs to be done in conjunction with the recommended jetting as per the attached bulletin released in 2009 to increase the fuel mixture. http://www.jabiru.net.au/Service%20Bulletins/Engine%20files/JSB018-2.pdf This mod was shown to me when I did the engine course at Jab 6 months ago. Cheers Vev

Hi SP6, No probs ... the answer is Yes and Yes You can tell the emulsion tube as it has 4 holes at 2.5mm in the side of it ... you cant mistake it when you have it in your hand. Yes the air density sense port is the one, however be careful when you drill it as its a big hole. Cheers Vev

SP6, For the 6 cyl only (doesn't work on the 4) ... drill the emulsion tube out from 2.5mm to 3mm and drill the air hole from the mouth of the carby using a 3/16. To further improve the EGT/CHT spread remove the manifold divider and replace it with a 12mm round. The carby mod came from the South Africans and has been tested but Jab in oz .. it works well. Cheers Vev

Jabiru says Compliance – Implementation Schedule  The changes detailed within this Bulletin are mandatory for all J170 aircraft. They must be carried out within the next 300 hours of flight or within 12 months of the date of issue of this Bulletin – whichever is the sooner. Hi Donkey, I wouldn't second guess a manufactures written safety directive unless I had something in writing saying you can .... I'm sure your insurance wouldn't hesitate to write you off .... I would also hate to think what sort of a defence you would put up in front of a court should a passenger get hurt or worse! If you are in doubt about the benefits, give Jab a call. Cheers Vev

I should have also mention there is a new mod to reduce flap defection too ..... Cheers Vev

This was posted on the Jab site regarding upgrades to rudder peddles and fitting a new ventral fin. http://www.jabiru.net.au/Service%20Bulletins/Airframe%20Files/JSB029-1J170.pdf Cheers Vev