Engine failure

[frank marriott]

Question:

 

You state a compression test - was it a leak down test and what were the numbers - just interrested . I run a 3300 engine and do a leakdown test every 50hrs - very interested in the actual numbers - I have 320hrs on mine.

 

Frank M

 

 

[hendonguy]

My maintenance log is in the hanger I will get the results and let you know yes we did the correct leak down test, I do recall the last valve set one of the cleanse was ever so slighty loose , maybe about 2 or 3 thou don't know if this was any warning of the coming failure

 

 

[Guest Maj Millard]

I was chatting to Rod Stiff at the Ingham Airshow, I should have asked him then if he would sponser it, damn, opportunity lost !!........................................Maj.....

 

 

[facthunter]

Jabs appear to be one of the best planes to crash in . The fuselage tends to stay intact and you have an engine in front of you for a bit of protection. They also rebuild OK.

 

Regarding the valve clearance changing. Increasing wouldn't indicate valve stretch, decreasing COULD, ( but may not) Nev

 

 

[Guest Maj Millard]

Facthunter, Yes they do appear to be a good aircraft to crash in. However if the damn engines stayed in one piece in the first place, you wouldn't have to risk your life crashing unneccesarily would you !!... And no, composit is not easy to repair, it's messy, and then you end up with a repaired structure, not as strong as the original, and probabily heavier also....................Maj...

 

 

[Old Koreelah]

And no, composit is not easy to repair, it's messy, and then you end up with a repaired structure, not as strong as the original, and probabily heavier also....................Maj...

If done properly, a composite repair is no different to a welded metal repair; it should have similar strength to the original stucture.

 

Proper preparation of the repair, including scarfing the join at the correct angle, are a big part of the repair.

 

 

[Ballpoint 246niner]

LSA= Low Silent Arrival, well done! Another Jab test pilot get's their wings. Glad to hear good skills and correct training got you down safe.

 

 

[Guest Maj Millard]

Old Koreelah, part of what you say is correct. I've held an FAA issued Level 2 Advanced Composit Certificate now for around 15 years, so I do know my way around a composit structure. Generally yes, it is possible to return the damaged structure to original strangth. Sometimes it isn't possible, depending on the position, or scope of the damage, without adding additional weight in the process.

 

Personally I'd be very wary of purchasing a repaired Jab, or any other composit aircraft after a crash repair, without talking with whoever did the job, and finding out the full scope of the repair, materials used etc. I'm sure you'd agree with me there.

 

I'd also be very suspicous of any major structural Jab repair after crash damage,unless it was carried out by the original manufacturer IE: Jab factory.....................................................................................Maj...

 

 

[Old Koreelah]

Personally I'd be very wary of purchasing a repaired Jab, or any other composit aircraft after a crash repair, without talking with whoever did the job, and finding out the full scope of the repair, materials used etc. I'm sure you'd agree with me there.

I'd also be very suspicous of any major structural Jab repair after crash damage,unless it was carried out by the original manufacturer IE: Jab factory.....................................................................................Maj...

Good points, MM. It's got to be put together right. After all it's just a whole lot of glue separating some tiny little glass fibres. I just like to defend a good composite product. I'd rather prang inside a Jab than many metal and wood aircraft with rigid, unyielding bits ready to impale you, trap you and do you harm.

 

 

[Guest Maj Millard]

Good points also Old koreelah, I've never had any dramas with the Jab fuselage and they do seem to do well in a crash. Before composits the basic welded steel tube fuselages proved themselves well in crashes, and are still used as the pilot protective structure in many ag planes. Early aluminum structures as used in many ULs were responsible for a bit of impaling in past years unfortunatly. The welded steel structures would deform but often stay together...As I often say "Flying is the best way to fly !"........................Maj...

 

 

[rick-p]

My engine has about 560 hours , it had a top end rebuild from an l2 about 200 hours ago , has been serviced correctly every 25 hours ,run on av gas 100 percent ,75 hours ago a level 2 did a 100hour service including a compression test , in the space of one revolution the engine went from perfect to life treating it was unbelievable how quickly it happen

Hi Hendonguy,

 

That is the way of life mate in one revolution we go from one thing to the next like my good friend who recently went in a flash of an eye from being fit and healthy to dead, his heart just stopped. Something broke because the manufacturer in his case just didn't get it right but there were no recalls for my mate. My point, never expect a warning that something is going to go wrong always expect the worsed and then you may just have an even chance of survival. A warning is a bonus!

 

I could go on but I may cop from Dex another "that's an unusual rant Rick".

 

I'm just trying to make a point!

 

Rick-p

 

 

[Old Koreelah]

On a totally different note: I should have followed my own advice while riding my motorcycle on the roads. Twice this week I have had to perform a radical manoeuvre to stay alive. To re-write a quote: ... never be surprised when a large vehicle pulls out in front of you; be surprised when they give way.

 

 

[Jeff Gordon]

Hendo, welcome to the JEF (Jabiru Engine Failure) Club.

Thank goodness my name has two fs in it!

 

 

[eightyknots]

Hi , we where on our way to goondiwindi fly in this morning about 10ks north of gore Queensland we had an engine failure in our lsa, jabiru we where in tiger country but managed to make a clear but rough field and able to do a forced landing , the plane got a fare bit of damage but we surveyed totally un hurt , just want to let people who that had heard of our accident and wondered if anybody was hurt , all ok , engine failure cause not know ,but not fuel

I am really thankful you survived this incident. It must be a horrible feeling when the fan at the front ceases to turn! So pleased you were completely unhurt!!

 

Hendo, welcome to the JEF (Jabiru Engine Failure) Club.

Bryon, you'll get flak over that statement!

 

And thank Warwick flying school for life saving engine failure landing training /practise

I think Warwick Flying School deserves a plug too.

 

 

[facthunter]

Yeah, good work. The training does kick in. That is provided you aren't the kind to panic. We should consider the engine likely to fail anytime. That means plan your take-off each time . Work out where you would go. Flying two-strokes it becomes second nature, but maybe gets put in the back of your mind when nothing goes wrong for a while.. Don't fly over what you can't land on. ( Haven't heard THAT for a while).

 

Just a point Maj. I consider the Jab as a Fibreglass plane to be much more repairable than what I call Composite.( ie carbon fibre.). However no-one knows the life of these aircraft. Even the rivetted thin skinned Al metal planes have a very finite life . The tube steel fuse, and wood spar is my favourite for repairing. (and generally)_Nev

 

 

[Bryon]

Bryon, you'll get flak over that statement!.

I dont think any flak I get over that statement can be worse than the way my pucker felt when I went through initiation for entry into the JEF Club

 

 

[Guest rocketdriver]

). However no-one knows the life of these aircraft. Even the rivetted thin skinned Al metal planes have a very finite life . The tube steel fuse, and wood spar is my favourite for repairing. (and generally)_Nev

Hi Nev

not a structures expert, just a long time user of airframes including gliders .....

 

As far as I am aware, the resin bonded glass fibre materials are considered (like wood) not to fatigue or corrode in use, unlike metal. However they can delaminate (and therefor weaken) if incorrectly manufactured (entrapped or evolved gas will do it), through chemical contamination attacking the resin (eg petrol in an epoxy resin fibreglass tank) or following a severe impact or overload. I believe that they soften and weaken if overheated (ie a black surface sitting out in Australian sun) but that the strength is restored once the temperature comes back down.

 

Hope I'm not teaching Grandma how to suck eggs ..... and would appreciate an update if I've got hold of the wrong end of the stick ....

 

cheers

 

RD

 

 

[Litespeed]

Good point, Rick. A famous test pilot is reputed to have explained his survival in a long career by saying that he was never surprised when the engine stopped; he was always surprised when it didn't.

Smart man. I survived over ten years of riding big bore bikes in traffic, open road etc and had a It will happen philosophy.

 

Always expect something to go wrong, whether it be a two-stroke mid corner siezure or some idiot looking straight at you but not seeing you.

 

I always thought unless a piano falls from the sky and hits me on the head- then anything else I should have seen coming.

 

No excuses- when you broken in pieces or dead- it does not matter who is at fault- the results are the same.

 

Same goes for aircraft engines- they can fail at anytime.

 

Always plan for the worst scenario and keep well ahead of the plane.

 

I constantly scan for a solution if it all goes to shit.

 

Hell, even in a car, I always expect some dick will run a red light and look.

 

Do not ever assume it will all be cool.

 

The ground is very unforgiving.

 

Phil

 

 

[Guest Maj Millard]

[quote="rick-p,It doesn't matter what engine you fly they are all engineered and everything and anything engineered can and will break, eventually.

 

Anyone who fly's around thinking that the type of engine they have is bullet proof and will never stop is only being a fool to themselves.

 

My two bob's worth!

 

Of course that's true Rick, which is why it is wise to go with the most reliable engine available. In 27 years of active UL flying I have had three engine failures requiring an emergency landing. One on a half VW conversion (carb ice) and the other two on early two-stroke single Ignition engines. I've been flying the 'modern' 4 strokes now for around 15+ years (mostly 912s), and have yet to have one on miss a beat.

 

At a rough guess I would have flown with at least a dozen different 912 engines of all models, in several different types of aircraft,.

 

I'm certainly not afraid of experiencing an engine failure, and I handled the three in the past without drama, with a lot less hours than I have now.

 

I do believe in having the best engine up front to minimize one's chance of a failure, and don't see any reason to invite failure by using less than the best, which is why I prefer the 912......................................................................Maj...

 

 

[Guest Maj Millard]

Facthunter, The Jab structure is a composit structure using fiberglass cloth encapsulated with polyester resin.

 

The carbon fiber and kevlar/carbon structurers are considered more 'exotic' examples of advance composit construction, and are common now in high-stress structurers such as aircraft. The repair of these 'exotic' composits can be more difficult and specialized.

 

The polyester/fiberglass structure is well proven and commonly used in boat construction and many other areas. It offers ease of repair with common and readily available materials.

 

The oldest know composit structure is well over 3000 years old. The basic mud hut reinforced with straw constitutes a composit structure . It is well proven and still commonly used today..

 

Aircraft metal structurers can go on forever also, unless totally damaged., as they are easily repaired and ultimatly rebuildable. This is especially so if those structurers are well designed and overbuilt in the first place. A great example of this is the DeHaviland DHC-2 Beaver, with most airframes flying today around 70 years old, and still operating safely . Many have been rebuilt or repaired many times over....................................................................................................Maj...

 

 

[alf jessup]

Thank goodness my name has two fs in it!

Well Jeff,

 

It could be called the Jabiru Engine First Failure club. so dont get to comfortable lol

 

Cheer

 

Alf (Absolutley love flying)

 

 

[hendonguy]

Removed the cylinder head from no.3 the damage is exact same as http://www.aaib.gov.uk/cms_resources.cfm?file=/dft_avsafety_pdf_502082.pdf. Even down to undercarriage detaching , no fin damage none on mine and no leak between head and cylinder , think from now on doing leak down test every 25hours and pull through every pre flight . Before this happen temps /oil pressure all normal , engine didnt run rough , just sudden vibration then a bang

 

 

[Guest pookemon]

So what is the "Blowing" they refer to? Is that Detonation? Reading that link - I think I might draw another line through Jabiru on my list... I wonder what water cooled heads would have done for it?

 

 

[Guernsey]

So what is the "Blowing" they refer to? Is that Detonation? Reading that link - I think I might draw another line through Jabiru on my list... I wonder what water cooled heads would have done for it?

They are available but not from Jabiru,

Alan.

 

 

[facthunter]

They are and they might help.... but..... The Jabiru engine was intended to be simple. Ungeared aircooled, simple carb and ignition system. You would be getting away from that and still not sure of the engine being reliable, and you have poured extra capital in too. When you do this sort of thing, Where do you stop? and what do you end up with.?

 

Reciprocating engines are always sitting there ready to spit bits out. Bad mechanics can make any of them unreliable. Conversely a bit of understanding and care can make a fairly ordinary engine go OK. Leaving the heads on a Jab too long is a recipe for disaster, The valve guides have to be good and the valves sealing well. Keep your eye on the compression. Nev