Jabiru trouble shooting

[frank marriott]

I don't get the advantage?

 

Battery to solenoid is about one foot. Breaking into this feed and inserting another solenoid/switch is shortening the heavy feed by six inches in the same area.

 

OR is the proposal to cut the feed to the buzz bar?

 

I must be thinking on the wrong track as isolating the solenoid with another one just seems like duplication to me????????? (In the same location)

 

 

[facthunter]

I don't know if you are addressing me, Frank but the idea is to have no live wires left. Isolate the battery. Solenoids are not trouble free. They can "stick" or not engage in the first place. The wire you use to activate a solenoid has to be live or it wouldn't work, so must be still attached to the battery. Nev

 

 

[frank marriott]

FH

 

I was addressing it to anyone. I get the point if the purpose was to isolate the buzz bar feed but as you state there is still power to the actuator wire to make it work.

 

A switch would have to be mounted out of reach or the live wires to it not giving advantage.

 

I can see the advantage where the main solenoid is mounted remote from the battery. The initial idea was to isolate the solenoid from inadvertent actuation and/sticking contacts - I get that point.

 

I just can't get my head around another solenoid, when the original is co-sited with the battery.

 

The set up proposed, is obviously not what I have in my mind, hense the interest in what is being achieved?

 

 

[facthunter]

Ideally you isolate it AT the battery. The non earthed terminal. Barring something falling across the terminals you are electrically safe. this assumes you can turn off other sources of electricity Like the alternator. caution turnoff some alternators with care . Some will not restart if the battery is dead as they are not self exciting.(like 6th class schoolboys) Nev

 

 

[geoffreywh]

Quote.............." OR is the proposal to cut the feed to the buzz bar?" ...............Yes certainly. There are two solenoids, One for the starter.....Then one for everything, the everything solenoid is mounted as close to the battery as practicable, if it is the same rating or higher than the starter one then the likelyhood of contacts welding are very slim. To get into ANY trouble with this arrangement you would have to have an emergency, plus have the contacts weld themselves shut at the previous switch-on......If you think that this might happen to you then don't buy any lottery tickets.... The "master " solenoid is operated by an earthing wire (switch or key ) ...The "master " plus comes from the battery, (close to the solenoid, remember) This way when you switch off. Everything is off but for 3 or 4 inches of battery lead. About as safe as it can be.................

 

 

[frank marriott]

I see where you are coming from now.

 

You still have 12V to the switch when switching the earth lead [all be it curent limited by the solenoid actuating coil] but still capable of making a spark if that is the reason.

 

Short of a mechanical device there has to be power to the dash to activate whatever safety device is fitted elsewhere.

 

 

[geoffreywh]

very low amp fused, switched wire,would sort that out too..Or if you are REALLY paranoid, then use a cable operated microswitch at the battery....

 

 

[Yenn]

Using a master solenoid seems to be a common method of cutting off a battery, but it still needs a live wire to the solenoid and its switch to work. If at all possible put in a manual, heavy duty master switch for peace of mind. I have the battery between my legs and the switch is just ahead of the fuel switch. Safe.

 

 

[frank marriott]

No worries, I was just confused at what gain was being put forward. My A/c is a LSA so mods to the electrical system not approved in any case.

 

 

[deadstick]

Here's a defect from the weekend, happened to my aircraft was on it test flight post new engine install. After installing the 3300 I noticed that the rubbers were quite soft and allowed a bit more movement of the engine so I rang Jab who informed me that the compound of the rubbers was recently softened to reduce vibration. End result after 0.6!!!!

 

 

 

[motzartmerv]

Yep, another aircraft U/S.. Thanx jab. This aeroplane has been out fof the air for 6 and 1/2 months while we waited for the back log of engines to clear.. Now we have to wait for new mounts.

 

Make of it what you will, but brand new components have failed in our aircraft 4 times in the last 18 months. Our last defect report instigated an AD re the starter solenoid. No worries Jab, keep sending us your rubbish to test for you.

 

I better shut up before the jab bashing accusations start flying.

 

 

[geoffreywh]

That rubber does not look right ..............it's a real shame, they can be so good. But not straight out of the box....David's J230 circumnavigates Australia without missing a beat...Someone I spoke to today mentioned that a new 6 cyl. has solid lifters. (hooray) aircooled motor clearances (at last) pressure fed rockers ( so they should have) and various other "updates"...........go figure

 

 

[AVOCET]

Here's a defect from the weekend, happened to my aircraft was on it test flight post new engine install. After installing the 3300 I noticed that the rubbers were quite soft and allowed a bit more movement of the engine so I rang Jab who informed me that the compound of the rubbers was recently softened to reduce vibration. End result after 0.6!!!!

You've got the rubbers the wrong way round , the male should be at the front so the load pushes against the "male bit "

 

The thrust on the female rubber just pushes it out of shape .

 

Cheers . Mike

 

Also , have the male facing forward on the top mount and at the back on the bottom ,

 

I've found this works ok .

 

 

[jetjr]

Pretty sure avocet is right. Its in the manual like he says

 

 

[AVOCET]

Pretty sure avocet is right. Its in the manual like he says

When I lived in bundaberg I was at jabiru fitting up the first 6cyl sp 6 ( the one that was stolen in WA ) engine with the soft rubbers , and rod stiff was watching and we both noticed the soft rubbers deforming ,

 

We then tried reversing the top rubber and it worked ok ,

 

I have also from time to time put an hose clamp around the offending rubber , that works ok to and you get the advantage of the soft rubbers ,

 

The hard rubbers are available but they do transfer vibration ,.

 

Cheers Mike

 

 

[motzartmerv]

Ok, well according to the current maint manual, on the Jabiru website. Instillation of 3300 engine page 10, it clearly shows the male rubber at the rear.

 

Should we get Rod to amend his maint manual to reflect this 'observation' he made?

 

 

[motzartmerv]

The constructors manual has the mounts inserted male to the front as you guys have described. We cant maintain a school aircraft on a 'constructors' manual, only the instillation and maintenance manuals which clearly show the reverse. This is bloody ridiculous!!!!!Apparently Rods observations made their way to one manual, but not the 'legal' manual that any L2 stating "IAW jabiru maint manual" has to use. Stand back and let the professionalism just whaft over you...

 

 

[deadstick]

Avocet, Jetjr, Thanks for the info guys, I spoke with someone at jab on the day about configuration as I was concerned with the amount of movement, they confirmed to me the male to the back and gave me the torque figure for the bolts of around 11nm IIRC and stated that the rubbers were being made softer now days for vibe reduction, The Jabiru aircraft tech manual is extremely vague on the install of these mounts here's what I used in conjunction with the info from Jab link page 10: http://www.jabiru.net.au/Manuals/Engine/JEM3302-4_Inst.pdf

 

Since your info here I dug a little further and went into the airframe construction book for the J240 and found this (page 3): http://www.jabiru.net.au/Manuals/Airframe%20Construction/Sections/Pre-Paint_Fuselage_Firewall_Fit%20engine%20and%20mount_J2400.pdf

 

Thanks again for the info I will be amending the defect report for the 230 to include this discrepancy, on the J 170 though, the picture attached is of the lower mount on the J170 it is starting to do the same, going by either reference it is installed correctly, could the rubber be too soft or something else? ideas???

 

Motz: I had a chuckle when reading your comment, I understand your frustration and sympathise. Looks like a case misinformation on the correct configuration lol... Think Jab should have this clearly set out in the LSA tech manuals and not hidden in the construction log for a home built.

 

 

 

[motzartmerv]

I may be creative but check the manual yourself :?)

 

 

 

[AVOCET]

Commonsence trumps porly written manuals

 

All I'm saying is if you put the top mount rubber male facing backwards it works great

 

Take the inissutive , less stress

 

Cheers

 

 

[deadstick]

Avocet,

 

what's that plane in your avatar?

 

 

[motzartmerv]

could the rubber be too soft or something else? ideas???

I have an idea...

 

 

[deadstick]

lol smashing the computer does nothing, I tried it once!!!!

 

 

[motzartmerv]

Commonsence trumps porly written manualsAll I'm saying is if you put the top mount rubber male facing backwards it works great

Take the inissutive , less stress

 

Cheers

Yes mate, unfortunately, we must maintain IAW with these poorly written manuals when we use the aircraft for hire and reward. The laws are not poorly written and not ambiguous in this regard. "yes your honor, I took the initiative" :)

 

 

[AVOCET]

Yes mate, unfortunately, we must maintain IAW with these poorly written manuals when we use the aircraft for hire and reward. The laws are not poorly written and not ambiguous in this regard. "yes your honor, I took the initiative" :)

Your kidding right ,?

 

Gong to court for putting the engine mount in the right way ?

 

Cheers Mike