Early signs … investigate..

I’ve had an annoying little crackle in the headsets for a while now but have had trouble pinning it down .. at first it was just a low level occasional click but has increased over recent flights to being quite invasive.

When I transmit or receive the radio goes clear as a bell.

Chatting with our visiting avionics specialist he suggested trying to isolate it by turning off circuits and devices and checking to see what happened .. problem was it was definitely more noticable airborne … so not so easy to start wholesale switch offs !

In the end .. the progressive nature of change … I noticed that if I turned the right mag off the click pretty much stopped .. so we had an area to focus on .. but no one in Jersey has a Jabiru and the forums are flooded with conflicting advice …

I also noticed on the last flight that the right mag drop suddenly increased to about 100 .. where the left was only showing about 40 drop ..

Time to ground her and check before any more flying ….

Time to call Paul H Smith at TLAC for a quick bit of advice…

Given the symptoms, he advised to check the Jabiru remanufactured HT lead and fitting out of the mag and, if that looked ok, double check distributor cap and rotor arm

In 5 minutes I’d located the problem … the right rotor arm was clearly not seated firmly and could move ever so slightly ..

At the first 25 hours of engine run time I had been super cautious and changed oil, filter, plugs, rotor arms and distributor caps. The arms were very difficult to get off .. later found they are epoxied in place ..

I had applied epoxy .. sparingly but, I guess, too sparingly … and this arm could move fractionally on its squared stem drive shaft.

Removed, and temporarily put back the original 25 hour unit having cleaned and epoxied

Engine start and run up … radio clear as a bell again …

Also .. Left and Right mag drops back to evenly matched at about 40 rpm each 😉

Fun in the clouds at 3,000′ post permit renewal

Saw that the cloud was clearing and rising so nipped out to buzz for a while

Then back for oil change at just over 25 hours again … decided the cost of changing every 25 far outweighs the short time it takes .. and gives you a great chance to keep on top if things

Day out …

So .. today was a different day … with the great help 2 of my boys Sam and Will …and a myriad of Airport Security, Fire and Rescue services, Jersey Air Traffic and the Jersey Aero Club, we managed to blow the dust off the trailer after 2 years .. and make great use of the fantastic alloy / carbon fibre wing supports … really steady …

Some shots from 2017

Just tidying some photos up to make sure I don’t lose them … you can see these are minus the root fairings … so pretty early flights ..

DCIM119GOPRO
DCIM119GOPRO
DCIM119GOPRO

D Day (Landing) 6th June ..

Nice bit of crosswind .. around 10 knots … Wills pretty much flew the whole thing and brought it in nicely .. also helped as he counted down the airspeed on approach … probably landed a shade too much speed … and a fair bit of rudder at the end … this ‘plane certainly teaches you good use of rudder

As mentioned in a previous post the cowl is a ‘re use’ of the original that I discarded after over trimming. On this flight (just under 90 mins) I was keeping a close eye on engine performance and temps … it takes a while to ‘settle’ any aerodynamic change and switching your cowling isn’t just a paint job !

Turned out to be quite close .. but did run a little warmer than usual .. and at one point reached 97’ on the oil temp … that turned out partly to be the cowl and partly Will was flying slightly cross controlled … “Ball in the middle” sorted the airflow and we dropped 4 degrees almost straight away.

I’ll double check the baffles at the front are not inhibited and that the cut out openings (which look fine) are indeed as large as the original cowl.

Plan to fly with this one for a few weeks on and off

(Another thing I noticed … in the sun .. the Matt black gets super hot compared to the plain white … really absorbs the heat)

New use for ‘old’ cowling

Many years ago .. late one night .. i was making final adjustments to the top cowling and manage to over trim it …. now it’s not easy to put back fibreglass that you have just carefully trimmed off .. so I trashed it, bought a new one and vowed to measure twice and cut once in future!

I could never bring myself to dispose of the now smaller top cowl so kept it

Now .. I’ve found a reuse … extended the over trimmed parts and plan to paint it to reflect the time or event ….

Finally – Smoke stress test completed

This part has certainly not been easy … to stress various values ends up putting parts of the aircraft at risk of being damaged if you don’t do it really carefully…

Given a max weight of oil tank, plus pump plus a full load of (baby) oil… the all up (unit) weight is 19,7kg .. you then need to cater for Forward factors of x 9 … side to side of x 4.5 and vertical of x 6

So Forward is a mere 177.3 kg

Side to side is 88.65 kg

And vertical is 118.2 kg

Will and I decided to removed the front windscreen to prevent any accidental damage caused by a straining strop moving and cracking !

And the 4 stainless turnbuckles that secured this so tightly held rock solid …

Also checked none of this impedes any control movement or even getting in and out !

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