Engineering Day – Skycraft Jabiru Course 1

What a fantastic day with a great bunch of people ….

Flew out from misty foggy Jersey yesterday to even mistier and foggier Gatwick and then long drive up to Holbeach to stay in a small pup overnight ahead of today’s starter course for those who want to know a bit more about the Jabiru 2200 engine.

Started with lubrication … a very good place to start …

Next … electrics … not everyone’s favourite …

Next … mechanical bits … valves and tappers and compressions ….

Other useful bits to write up from my little notebook.

  • Oil breather pipe should rise initially before dropping away to catch bottle …
  • Oil excess overflow should not have a drain pipe that could end up pressurising the crankcase
  • Carb balance air pipe should come from filtered side of carb and into filtered side of air filter …should intrude by 20mm for good fit
  • Check the carb is earthed to engine
  • Flywheel bolts now have special new nordloc washers and new bolts .. the old ones could well be difficult to get out… heat can be allied to break the loctite .. but .. make sure you protect the magnets
  • When setting tappets ALWAYS do it cold .. so good plan .. drain oil hot from a run .. leave overnight to fully drain … then take a plug out to reduce turn pressure on prop and get piston to TDC then adjust as above
  • Good idea to make a mark on stator for where TDC is per cylinder

Approvals ….

Got an email from the busy LAA this morning … working on a Saturday … so good to get feedback.

Having never submitted an aircraft modification before I am still learning the sequence and paperwork that is required.

The 12 pages of what is called a MOD3 went through quite a lot of iterations but, even though we have now reached a high degree of acceptance I have omitted to provide some other elements:

  • A completed worksheet – basically setting out the key elements
  • An updated section for inserting in the Pilot Operating Handbook POH
  • A PMR – Permit Maintenance Release

Spent this evening completing these so just need to meet up with my local LAA engineer for counter signature ..

Update to POH

POH Addendum Smoke System
Smoke System – Principle of Operation
The oil smoke tank uses a kit supplied by American supplier Smokin Airplanes and comprises the following elements:
– Smoke oil tank with associated pump
– Feed pipes and delivery pipes
– Spray bar fittings for exhaust pipes
– Electrical switches and fuses

The tank accepts a paraffin based oil (Baby oil) and the electrical switch , momentary switch provides power to the pump which draws oil from the tank into aircraft grade aeroquip rubber hosing.
The hosing routes to the rear of the stainless bulkhead and passes into a T bar aeroquip fitting that splits the single feed into a steel braided double feed that connects to spray bar atomiser injectors fitted into each exhaust outlet.

Fitting Of Oil Tank
The oil tank is fitted into the front seat (P2) location. The seat base and seat back are removed prior to installing. This leaves the Sherwood standard plywood seat base which has had 2 holes drilled in to accept 2 alloy pins on the underside of a tailor made ally mounting tray.
The mounting tray has lips on all sides to ensure the oil tank does not move in any direction.
Underneath the plywood seat base 2 alloy brackets have been riveted in position on the outer edge of the 2 longitudinal seat rails. These brackets accept a 1” wide ratchet strap.

Weight and Balance Consideration
As the oil tank is located in the P2 position, and this location is dead centre on the C of G , mainspar there is no change to weight and balance whether the oil tank is empty or full.

Filling the Tank
The tank is generally filled outside the aircraft but it can be filled in situ with a suitable long stemmed filler flex pipe. Filling is through a large hole in the top of the tank which has a securing screw cap. Do not overfill the tank .. 3/4 is sufficient for approx 4 mins of continuous smoke.

There is an overflow pipe if excess washes over in any steep turns. This pipe routes to the underside of the aircraft behind the u/c.
A quick release break valve is fitted to prevent spillage. The tank can be removed , even if oil remains in the tank.

Smoke Operation
The smoke can be operated once the engine reaches suitable temperature. Usually 150’ and above EGT.

There are 3 ways of operating the smoke:
– The main switch panel has a 3 position switch, continuous on, Off and Armed for intermittent
– A remote Push button allows momentary operation of smoke .. IF the primary switch is in the UP (Momentry) position
– If the primary switch is set to ON, the. The pump operates until it is turned off.

Note .. a red light is illuminated all the time the pump is in operation
Note .. the pump will continue to operate even if no oil is in the tank amd the switch is in the ON position.

Smoke – 2nd test

A bit if blue sky and yes… blxxdy freezing .. but hey lets try second attempt ..

Tried 1.4 instead of 1.5 on the mixture and smoke was a little less ‘full’

Smoke on …… go

Last Sunday we finally had a slight lull in the weather and .. having fuelled up … loaded about 30% of smoke oil into the oil tank.

Having started up and warmed the engine whilst waiting for the fueller to arrive I had a nice warm engine so was ready to taxi out pretty much straightaway.

I made a quick mobile call to Jersey ATC to request circuits and also advise that it would be a second test of the smoke system. There was a short delay whilst the clearance chap checked out with the tower and all ok.

Duly taxied out and lined up on runway 26 at Jersey .. with a nice warm engine … I had said I would probably do a full normal circuit before doing a long runway pass at say 700’ and try the smoke on and off serveral times.

Just after take off .. I banked out left towards Corbiere lighthouse and quick glance in my new small rear view mirror … thought .. let’s just flick the smoke switch for say 2 seconds and off…


Lots of lovely white billowing smoke and stoped the instant you turned off. A few more on,off combinations and works a treat.

Clearly my previous setting of 2 full open valves on the mixture was way too rich .. Smoking Airplanes had suggested trying something between 1.3 and 1.6 .. I tried 1.5

Awesome smoke trail ..and BEST thing … if you waited for say 2-3 seconds and then looked back .. you could see the biplane wing wash and prop wash swirl beautifully symmetrically in the trailing smoke.

Will try a rear facing go pro on the next flight ….

Slightly fast approach….

Here is a slightly fast approach around August 2019 …

It was slightly choppy conditions but I planned a touch and go and … as you can see … the touch was ok but the starboard wing lifted a little as the approach speed was too fast .. 😊

Smoke – First

The other day was a very cold but at least clear day so I half filled the smoke oil tank with baby oil and ratcheted the securing strap up for its first proper air test.

I’ll need to source a better power plug connector .. these ones with crimped spades that push into plastic connector blocks are very weak … but should be ok for initial test.

Having run an initial 1 second ground test to make sure the pump operated from the rear cockpit switch I set off to get in and warm the engine

Getting in was its usual squeeze in the winter.. with around 5 layers on .. its cosy though and you soon dont feel the cold as everything gets going

I’d pre briefed I think it was Russell in ATC that I’d like to do a circuit just to make sure all fittings were stable and my feet remained clear of all fittings in terms of rudder access and pump … and then advised I’d like to do a straight pass over the runway at around 800′ to try the smoke …the idea being that if anything was to happen .. I could dead stick down ..

All went fine and setup the approach for the first 800′ overly… slight thing to factor was an ATR had just take off as I was on short final so I was advised to turn before I flew through his prop wash at the end of the runway .. not a problem as I usually turn just before the end to clear the centre line

Anyway … my little wing mirror I fitted a few weeks ago revealed zip coming out of the back .. tried the switch several times and nothing…

Did 4 more circuits and finished with a usual very tight 1 min circuit to land … the ATC controller was awesome as I called close downwind she cleared another FlyBe ATR to take off and he was pretty slow to move so I held a few more seconds until I saw him roll then wing over on a nice tight right base and touch down just a few seconds after his wheels left the ground…

Thanked ATC and wished a Happy New Year and taxed in to check why the oil wasnt working …

Checked all fittings and switches and fine …the realised.. doh … to prevent any spillage I’d turned the flow valve fully off … this means loading the tank is a nice dry affair ….

Anyway .. valve duly turned on and a hop back in and clear prop .. restart …and hey presto .. smoke … not as billowy as I’d like.. but smoke

Stopped the engine hopped out and found a very wet undercarriage…so it’s too rich

Turned mixture , flow down from 2 full turns to 1

Hopped on again …and restart… not much smoke.. but less liquid …

So need to check what flow valve setting is optimal and also emailed Smokin Airplanes in US to see what is best burn rate for oil on this type of.engjne … prob better at revs around 2700 vs on hard standing around 1800

Watch this space ….. 😊

Last flight of 2019

It’s been such rubbish weather during the past few months , and the odd day it has been good we have been in the U.K. ..

Top that with a drop dead CAVOK day with 3kts … and it was Christmas Day .. and Jersey airport was shut ….

Mind you .. we all need to count our blessings … the airport DID open … briefly …. to let a medivac aircraft fly in from Guernsey .. an Aurigny aircraft, to pick up a sick person then fly them to the U.K. .. usually Southampton .. fingers crossed all worked out ok …

A few shots from the last days flying of 2019 … pretty cold .. so usual 4 layers top and bottom … plus a life vest on top of a flying suit and sheepskin … that was tight in the cockpit !

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