Latest Jab chat

[Ultralights]

The engine pods do not look very slippery, lots of drag, they look quite deep, identical to the single engine front end, and cut off sharply at the rear. looks quite draggy..

 

 

 

 

 

 

 

 

 

 

 

 

 

 

i think the aircraft they looked at for inspiration is the Dornier DO28.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[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

 

 

[facthunter]

If you want to get an idea of what it would fly like on one engine Put a weight equal to the engine in the back leave the flaps down and try to fly it. Oh and put a big spring on the rudder trying to pull it one way too. Nev

 

 

[jetjr]

The twin concept is being done in south africa, surprised to see Jabiru even talking about it.

 

Shadowlite are also the guys putting the efi setup together and some other good mods for the engines. They also have a very good reputation there for reliability. Rod jumped on their efi work in a previous note. i agree with a well sort efi, many of Jab engine issues might dissappear.

 

The twin is discussed elsewhere as being highly valued for twin training and will be a cheap option to build time and skills. Over there the have MTOW to 760 kg?? 160 hp might make this work better in high and hot locations

 

Regarding the new prop, yes its Bolly making blades to Jabiru spec. ive been running a very similar one for over a year and it is an impressive upgrade.

 

 

[Guest Nobody]

Yea, I meant has anyone flown the tecnam twin. Does it have csu? Not that electric rubbish , proper feather ability?

I haven't flown it but the props are MT and do feather. The one engine out performance is pretty good for what it is but heavy and on a hot day might be a bit slow, still better than a single one engine out.

I suspect that these small twins are aimed at the training market where low hourly cost is a main driver and cruise speeds not so important.

 

 

[geoffreywh]

The roller lifter addition is a bit odd. ( It's NOT roller rocker) I can't see why they would spend lots of time and money developing something with so little return for effort? There are other places that would benefit from development with much better results.................... How about an alternator that puts out 20amp.( so you can runs glass panel and radio whilst taxying) ......Through bolts and studs that don't break............. A fuel system that has even distribution........... A sump that holds more oil.......... A longer dipstick ( not a screw in stick) ...The hollow pushrod and pressure fed rocker addition was such a good improvement ( It made the engine just like EVERY other one I ever saw)....I think that their priorities are misguided.........I could go on ( and often do)

 

 

[fly_tornado]

welcome to bundy!

 

 

[facthunter]

Roller followers to pushrod engines have become pretty universal. Camshaft lobe and follower face wear are pretty much eliminated. I wouldn't hold that against jabiru. The feathering is essential and the twin market for training might be worth aiming at. Cruise performance is not a problem but it must be able to fly on one engine. It won't be certified unless it does. Nev

 

 

[Deskpilot]

The engine pods do not look very slippery, lots of drag, they look quite deep, identical to the single engine front end, and cut off sharply at the rear. looks quite draggy..

 

 

 

 

 

 

 

 

 

 

 

 

 

 

i think the aircraft they looked at for inspiration is the Dornier DO28.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[ATTACH]22296[/ATTACH]

 

 

That's the one I was thinking about, and yes Howard, disease, not decease. Ain't quite dead yet. Just parts of my mind have passed their 'used by date'.

 

 

[Guest Nobody]

The feathering is essential and the twin market for training might be worth aiming at. Cruise performance is not a problem but it must be able to fly on one engine. It won't be certified unless it does. Nev

The constant speed prop is also important so that the engine can deliver maximum power at the slow one engine climb speed. The lack of a hollow crankshaft could be a deal breaker....

 

 

[geoffreywh]

Why all the speculation about a twin???? On and on it goes. What's it got to do with R.A.A.? Nothing at all that's what..................Speculate , if you will , about how to get more reliability into the present singles!................. Quote "Camshaft lobe and follower face wear are pretty much eliminated" Yes, they are , I never heard of Jabiru engines suffering from premature cam lobe/follower wear, did you? MOST other engines put up with sliding contact, even very, very hot ones (hot as in high performance) that run 20,000 plus rpm...Never did see any undue wear there.......There was the Lycoming issue of course, but there the cam was placed very high and invited trouble... Please forget the silly twin.....

 

 

[facthunter]

Please continue to tell me what I can comment on. If I find something that doesn't concern me particularly, I skip it and come back later maybe? That works for me...The topic is ' latest Jab chat" Nev

 

 

[jetjr]

And the twin has little to do with Jabiru Australia I suggest so rules would be different.

 

I like the fact that someone in the Jabiru network is developing product and moving ahead. Perhaps we need a Shadowlite Agent here :)

 

The roller followers is an incremental upgrade and looks to be a good thing - I cant agree the hollow pushrods and hydraulic lifters were. Youll find pretty limited support even in Jabiru for that comment

 

 

[turboplanner]

The roller lifter addition is a bit odd. ( It's NOT roller rocker) I can't see why they would spend lots of time and money developing something with so little return for effort? There are other places that would benefit from development with much better results.................... How about an alternator that puts out 20amp.( so you can runs glass panel and radio whilst taxying) ......Through bolts and studs that don't break............. A fuel system that has even distribution........... A sump that holds more oil.......... A longer dipstick ( not a screw in stick) ...The hollow pushrod and pressure fed rocker addition was such a good improvement ( It made the engine just like EVERY other one I ever saw)....I think that their priorities are misguided.........I could go on ( and often do)

Through bolts?

 

 

[facthunter]

Most think that is detonation Turbs. Nev

 

 

[geoffreywh]

Then fit an electronic ignition with a knock sensor! My wife's 1999 car has it. How hard is that? The problem goes away.Maybe performance will suffer, but no more broken bolts..That may be simplistic , but goodness me, do something before someone dies......... The Jab engine is VERY good in most respects but woeful in others...There doesn't seem to be a guiding hand on the tiller.............

 

 

[fly_tornado]

I don't think that Jabiru are going to fix a problem that's bringing in a lot of work for them. Those rebuilds bring in much needed money when new sales are slow.

 

 

[facthunter]

Bit conspiratorial don't you think ft? Doesn't stand any test of logic either. Nev

 

 

[turboplanner]

Where did we go with carb ice - it's not the most sophisticated system in the world, and there's a massive gas expansion from ice.

 

 

[facthunter]

A momentary stuck valve can do the same thing. Nev

 

 

[fly_tornado]

Bit conspiratorial don't you think ft? Doesn't stand any test of logic either. Nev

Jabiru didn't invent designed obsolescence.

 

 

[turboplanner]

If there's one thing that gets up my nose as a professional in the automotive/transport industry it's this ridiculous term "designed obsolescence"

 

With decades of employment in the industry I've never seen it, and it's an insult to the tens of thousands of people who fight to keep their jobs and their company afloat in an intensely competitive environment.

 

Apart from that the Trade Practices Act would most likely class that as Unconscionable Conduct.

 

 

[fly_tornado]

Do you remember when cars used to rust out?

 

 

[Guest Andys@coffs]

Do you remember when cars used to rust out?

Ummm if it was planed obsolescence wouldn't they still be doing it.......isnt that just another good example of evolutionary improvement as our technology and understanding improves?

Sortof looking forward to some evolutionary improvement in RAAus shortly......of the large step variety...where the basis is science/process and not marketing!

 

 

[fly_tornado]

The car industry got together with the insurance industry and found it was easier to obsolete cars on economic grounds. $1000 for a plastic bumper bar that costs $50 to mass produce.