550 hour old jab going fine

[Marty_d]

Not that I left any deliberate things for him to find, like I did with a building inspector at Alice Springs when I left out most of the bolts which held the roof trusses onto the walls . ( No he didn't notice and while I didn't tell him at the time, I have told the story ever since)

Someone recently told me the story of the brown M&M's... FACT CHECK: Van Halen's Concert Contract Required No Brown M&Ms?

 

Long story short, Van Halen had a clause in their performance contracts stating that they required a large bowl of M&M's to be provided, but with all the brown ones removed.

 

The reason they did that was to check how well the venue management was reading the contract. If they couldn't be trusted with something as simple as removing the brown M&M's, maybe they couldn't be trusted with setting up the venue safely...

 

 

[cooperplace]

All are good points however finding a non arrogant, professional LAME or L2 with in depth real current knowledge on all variants of Jabiru isnt easy.That manual flap mechanisim is pretty ordinary even when new. Sure had a few frights with it releasing from St 2 to 1 on short final, not only in terms of aircraft performance but the loud bang it makes.

 

Ive seen numerous attempts to improve with limited success

 

Get rid of it and fit electric version, if you have wings off it can be mounted pretty simply. Worst failure mode you have ten is flaps that wont come down or up, in either case you can handle it.

I prefer the manual flap setup, and have never had a problem. But I've never done 2 to 1 on short final. Why would you do that? On touch-and-goes I'll go 2 to 1 with the wheels on the ground, but apart from that all 2 to 1 changes require positive rate of climb and must be gently done. in my opinion. I'm talking about LSA/55.

 

 

[jetjr]

I didnt "do it", it does it itself

 

Locating lug slips out under load, if you havent experienced it before, be prepared

 

Talk about brown M&M's

 

 

[Marty_d]

I didnt "do it", it does it itselfLocating lug slips out under load, if you havent experienced it before, be prepared

Talk about brown M&M's

I think it's Pollywaffles if that happens.

 

 

[coljones]

It's about the money Turbs.In some types of operation there are inspectors for every step.

Perhaps more resources spent on inspection and checking than on doing the job.

 

But in the sort of place we would use, there would normally be just one mechanic assigned to a job. Imagine he is interrupted to check out an unrelated parts delivery and then it is lunch time and he forgets that sump-plug. After all, it was finger tight so it looked alright.

Inspections are part of doing the job just the same as proper training to do the job correctly the first time.

 

 

[coljones]

I think it's Pollywaffles if that happens.

No, not pollywaffles. Though it is character building the first time. You learn to set full flaps but leave your hand on the handle for a few moments to ease the bang if it releases.

 

 

[Bruce Tuncks]

My flap detente works ok jetjr. The fit of the plastic is tight and the arm is springy with extra slots sawn into the moulded cover bit. I'll take a picture later today.

 

I do need to push it in firmly when selecting #2 , in fact sometimes if high, I use 2 hands.

 

Actually it is good to know that it will only slide back to #1 if it slips out. Wow the bang would give me a fright too, and I would agree with going to electric flap actuation. It is only the weight penalty which stops me now.

 

 

[turboplanner]

My flap detente works ok jetjr. The fit of the plastic is tight and the arm is springy with extra slots sawn into the moulded cover bit. I'll take a picture later today.I do need to push it in firmly when selecting #2 , in fact sometimes if high, I use 2 hands.

Actually it is good to know that it will only slide back to #1 if it slips out. Wow the bang would give me a fright too, and I would agree with going to electric flap actuation. It is only the weight penalty which stops me now.

I like electric trim, because you can just give a lazy flick of the finger as you fly along, based on the way the controls feel, however, with electric flap, you have a long wait before the flaps get to where you want them, and in the Jab you need to be on the mark with the visual market to avoid over-running the position you wanted. On the PA 28, mechanical allows you to do something much faster, and the mechanical locks allow you to do it without having to look at anything. I can't remember the LSA55 manual flaps, so they may not have the same type of locks.

I haven't looked at the Jab rod design, but I have had a lot to do with rod ends over the years and seen many bent. Almost always this is because there is fouling of the linkage at some point, and the person operating the control manages to get it to work, but via the screw section bending rather than the linkage turning the eye.

 

If you have to push the flap lever in firmly, that could be the cause and is worth examining, perhaps with the flap cranks disconnected.

 

If you're pushing a detent button, disregard.

 

 

[facthunter]

Powered flaps are necessary in larger aircraft, but why use them where you don't have to?. A well designed latching set up won't disengage. You can design it so load forces it into the detent more. Manual flap is far quicker and you don't have to watch a dial move. There are times you want to use it quickly. Dump it on the ground for more braking effect or jump a fence or ditch . OR correct an asymmetry quickly. Flap assymetry?? Never mentioned or designed for in OUR environment. Possible? Sure is and it'll give you a roll effect the ailerons may not overcome. Nev

 

 

[jetjr]

Because unless your an experimental, you can only fit what Jabiru designed. The manual flap is pretty rough design and relies on the flex in the handle and a nylon lug to hold in plce

 

Stage 2 sees flaps have significant mech load on the lug and it pops out. Dropping a stge of flap at landing could easily cause a prang. As could flying with one or no hands.......but thats what you have to do to hold it in place reliably.

 

The electric setup is pretty good and has benign failure mode

 

 

[facthunter]

You should be able to fly with one hand. You do it all the time. and you should be able to apply power at any time during the approach. Having to hold the flap in place is not satisfactory. The design is unsafe and should be rectified. A "proper" job for the CASA? Flaps generally are not treated seriously in RAAus. They are a primary control at times not just a means of getting the stall speed in the complying range. Nev

 

 

[cooperplace]

next time I'm in the jab I'll check that lug. I always give the lever a little jiggle every time I move it to ensure the lug is properly engaged. I've never known it to pop out of 2, but I'll bear this in mind.

 

one reason I like mechanical flaps is that in a forced (unpowered) approach using 1 stage I could quickly pull in 2 stages of flap to clear an obstacle, like EK Gann at the Taj Mahal. I know I could do this because I've practised this maneuver.

 

 

[turboplanner]

next time I'm in the jab I'll check that lug. I always give the lever a little jiggle every time I move it to ensure the lug is properly engaged. I've never known it to pop out of 2, but I'll bear this in mind.one reason I like mechanical flaps is that in a forced (unpowered) approach using 1 stage I could quickly pull in 2 stages of flap to clear an obstacle, like EK Gann at the Taj Mahal. I know I could do this because I've practised this maneuver.

It saved my life in a Victa

 

 

[Jabiru7252]

I decided to have a close look at the oil I drained from my Jab this weekend just past. It's done about 12 hours. By close look, I mean really close so I dragged out the microscope. I examined a drop of oil from the oil filter and a drop of new oil. Nothing to be seen, not a sausage. Both looked the same. Now we're talking about an engine that's done < 150 hours, still in diapers so to speak. I'll do the same at 500 hours (at the rate I'm flying, that will be 2057) and see what the oil looks like then.

 

 

 

[Bruce Tuncks]

Good stuff guys. I agree that the flap control is not worry-free and I will look for a way to improve mine. For example, the flap lever could incorporate a bicycle type brake lever or a push-pin which could go to a lock pin of some sort.

 

I had a good look at it today and while mine was done properly with no bending load applied to the rod-end shaft, it is true that most of the swivel action of the rod-end has been used up and it would be an easy mistake to use all of this swivel up and then leave the rod carrying bending load at the threaded shaft....ouch!

 

After what Oscar found, there should be a service letter come out for everybody with the old manual setup to check they don't have this defect.

 

 

[turboplanner]

I decided to have a close look at the oil I drained from my Jab this weekend just past. It's done about 12 hours. By close look, I mean really close so I dragged out the microscope. I examined a drop of oil from the oil filter and a drop of new oil. Nothing to be seen, not a sausage. Both looked the same. Now we're talking about an engine that's done < 150 hours, still in diapers so to speak. I'll do the same at 500 hours (at the rate I'm flying, that will be 2057) and see what the oil looks like then.

A lot of transport operators take advantage of oil analysis, particularly where one cylinder costs about the same as a Jab engine; the're aiming to get about 1.5 million kilometres out of the engine, and it's worthwhile if microscopic metal particles are showing up to address the issue, even if it's only a minor issue on one cylinder.

This is usually a measurement of wear, or premature wear rather than catastrophic combustion chamber failure.

 

 

[cooperplace]

It saved my life in a Victa

really? can you tell us about the incident?

 

 

[cooperplace]

I I mean really close so I dragged out the microscope. I examined a drop of oil from the oil filter and a drop of new oil. Nothing to be seen, not a sausage. Both looked the same. .

just standard bright field illumination? what magnification is needed?

thanks

 

 

[turboplanner]

really? can you tell us about the incident?

I had just soloed, and a couple of lessons later the instructor took me out to the training area to celebrate. He did a barrel roll on the way out, followed by a flight up one of the local drains, below ground level, a general look around the boundaries, and then I was free to solo out in the Training Area. As soon as I got out there down went the nose and I was flying across a swamp about six feet above the ground looking down at the ground as you do. Suddenly I realised I was coming to the bank of the swamp. Not only that, but there was a row of pine trees around the bank. I was too close to risk a sharp turn, so I gave it full throttle and pulled back on the stick. The nose rose for a while, then, at flying speed, wouldn't come up any higher than about half way up the trees. I was intrigued at how long it was going to take to die compared to a car crash, and the usual life flashing before your eyes occurred. As luck would have it, we were doing our BAK in night classes ahead of our actual flying, and suddenly out of my head came "full flap produces best lift and slowest forward speed". I yanked the flap lever up to full flap, the aircraft rose like a lift, easily clearing the trees, and I'd learnt a lifetime lesson not to engage in low flying.

Caution: I lucky enough to pull it off because full flap position on the V115 was limited to allow it. There are other aircraft, like the C172 with full flap angles that would cause the aircraft to bog down and stay more or less at the same level, so I wouldn't recommend trying it.

 

 

[Jabiru7252]

just standard bright field illumination? what magnification is needed?thanks

Just a standard light microscope, subject illuminated from below using diffused LED light, hence, bright field illumination. I used 100x and 400x and couldn't see anything. Microscopy is a hobby going back 40 years, but I make no claim as to being an expert.

 

 

[turboplanner]

Just a standard light microscope, subject illuminated from below using diffused LED light, hence, bright field illumination. I used 100x and 400x and couldn't see anything. Microscopy is a hobby going back 40 years, but I make no claim as to being an expert.

It might pay to make a call to the technical departments of Shell or BP to find out what magnification they use.

On oil report, you would normally send then a sample of the oil at regular intervals, and they will tell you when to change the oil depending on what they see (not sure if that's the number of metal particles, or the amount of breakdown of the oil). You'd then have a good standard to work from.

 

 

[Bruce Tuncks]

What clean oil! I would like you to look at a sample of mine.

 

Did you open up the filter too or is that not due? I cut mine open and there is usually a few flecks of metal.

 

Also I get some black sludge on the inside of the filter where the magnets are.

 

 

[turboplanner]

What clean oil! I would like you to look at a sample of mine.Did you open up the filter too or is that not due? I cut mine open and there is usually a few flecks of metal.

Also I get some black sludge on the inside of the filter where the magnets are.

You pulled your engine down, and it's near impossible to clear all the metal out without totally disassembling every component, washing the cases in a tub with cleaning solution etc. which would by why you might see flecks even from oil-change day.

Jab said he couldn't see any under his microscope, which could indicate a very clean engine.

 

 

[Jabiru7252]

What clean oil! I would like you to look at a sample of mine.Did you open up the filter too or is that not due? I cut mine open and there is usually a few flecks of metal.

Also I get some black sludge on the inside of the filter where the magnets are.

I haven't cut my filter open yet. I have not found any specks of metal in previous filters. Maybe I'll run one of my super magnets through the oil. If you're at the club this weekend I'll bring the gear and we can have a look. (Then do a leak down test?).

 

 

[cooperplace]

I had just soloed, and a couple of lessons later the instructor took me out to the training area to celebrate. He did a barrel roll on the way out, followed by a flight up one of the local drains, below ground level, a general look around the boundaries, and then I was free to solo out in the Training Area. As soon as I got out there down went the nose and I was flying across a swamp about six feet above the ground looking down at the ground as you do. Suddenly I realised I was coming to the bank of the swamp. Not only that, but there was a row of pine trees around the bank. I was too close to risk a sharp turn, so I gave it full throttle and pulled back on the stick. The nose rose for a while, then, at flying speed, wouldn't come up any higher than about half way up the trees. I was intrigued at how long it was going to take to die compared to a car crash, and the usual life flashing before your eyes occurred. As luck would have it, we were doing our BAK in night classes ahead of our actual flying, and suddenly out of my head came "full flap produces best lift and slowest forward speed". I yanked the flap lever up to full flap, the aircraft rose like a lift, easily clearing the trees, and I'd learnt a lifetime lesson not to engage in low flying.Caution: I lucky enough to pull it off because full flap position on the V115 was limited to allow it. There are other aircraft, like the C172 with full flap angles that would cause the aircraft to bog down and stay more or less at the same level, so I wouldn't recommend trying it.

Hi TP, thank you for posting that. When I was learning, my instructor took me thru the scenario in which the jab engine has failed, we're in a glide approach, and aren't quite going to make our designated landing spot because of an obstacle on short final, so a quick pull of the flaps lever to #2 gives maybe 20 ft, and hey presto, you're home OK. I still practice this (with imaginary obstacles!) but I've never needed it.

I avoid low flying like the plague: as I see it, there are two things that are your friend: airspeed and altitude.

 

Stay safe!