J230 @ YSWG

[Captain]

Postscript No 2

 

Thanks for your note Guy.

 

 

 

Haven't "dropped in" to Tumut yet, but will next time they have a BBQ get-together.

 

 

 

And thanks again for pursuing the Mallala. Don't spend any more time on that and I'll call the racetrack as the next move.

 

 

 

Postscript to the build.

 

 

 

Did a 12.5 hours detailed inspection today, and prodded + poked + wiped + torch&mirrored everything I could find throughout the aircraft, and nothing was loose or leaking or doing anything that it shouldn't.

 

 

 

Not a sign of any oil leak or weep.

 

 

 

And on speed achieved, I now have corrected airspeed constantly in front of me on the Dynon's screen, as derived from the OAT ..... and it is clear that she achieves an actual 115 knots in cruise at 2850 rpm at between 2500 and 4500 ft.

 

 

 

This week will muck around to find out what throttle settings are needed for 120 knots actual.

 

 

 

Regards to all who are interested

 

 

 

Geoff

 

 

[Captain]

Postscript #3

 

As a further postscript (albeit a little late), the aircraft is now over 30 hours and I gave it a full and detailed inspection at 25 hours.

 

 

 

All went well with no problems found. All head bolts checked and all torques were spot on.

 

 

 

Oil and filter change done and converted to Shell Multigrade for winter.

 

 

 

Have also completed all of the Service Letters and Bulletins that apply, and no worries there either..

 

 

 

No major issues so far and the furthest she has been is Wagga to Gawler & return, about 900 Nm at an average 110 knots @ ave 25.6 lph.

 

 

 

Regards Geoff

 

 

 

[Guest Bretto]

Just finished reading this thread from the start

 

WELL DONE Geoff!!!

 

Remarkable job there and a great guide for anyone considering building there own plane

 

How much cheaper is a kit Jab over one that is built in the factory just out of curiousity?

 

 

[Yenn]

You surprise me when you say the torques were spot on. Most Jab engines take over 25 hours for the heads to settle down, there is usually a need to tighten up especially on the exhaust side. Are you sure your torque spanner is calibrated correctly?

 

 

[Captain]

Bretto

 

 

 

From memory the kit was in the low $50,000's and the engine was about $18000 almost 2 years ago ..... say $70000 - $75000 with a few bits and bobs that I ordered from Jabiru later, so I reckon that the factory built J230's at mid to high $90's are GREAT value and a credit to Jabiru IF you just want a standard aircraft.

 

 

 

Mine went past that just on instruments and prep/painting without putting a value on my time @ well over 1500 hours but which I was happy to write off against the enjoyment of building exactly what I wanted.

 

 

 

I have no idea what is the price of a factory built J230 with Dynon 180 and AvMap and upgraded analogue gauges etc etc, but I would guess that it would be over $110,000.

 

 

 

Yenn

 

 

 

I expected to have to torque up the head studs a bit, but no. Not one needed anything.

 

 

 

Didn't have to touch the prop bolts either.

 

 

 

My torque wrench is a good quality Warren & Brown beam type unit and while I have not had it "calibrated" like a LAME would, I have compared it against 3 others (including one that had been calibrated in the past 12 months) by torquing up a range of bolts on my bench to the range of torques typically needed to service the outside of a J engine (say 7 - 35 Nm) , and it reads accurately. It is certainly not "way out".

 

 

 

This is interesting as my engine doesn't have a squeak of oil coming out of it anywhere and the torques are good. I wonder if this all might be a derivative of running EGT's and CHT's that are cooler than was previously the case.

 

 

 

Does anyone else support Yenn's contention re head torques etc?

 

 

 

Regards Geoff

 

 

[Captain]

Thought some of you may be interested to see some shots of the panel in cruise today, and the engine + instrument readings that apply in my case.

 

[ATTACH]6260.vB[/ATTACH] [ATTACH]6261.vB[/ATTACH] [ATTACH]6262.vB[/ATTACH]

 

 

 

 

 

[Geoff]

Is 28.5 lph normal fuel burn Geoff?

 

 

[Captain]

Is 28.5 lph normal fuel burn Geoff?

G'day Geoff,

 

 

 

That is about what I get, but bear in mind that the calibration might be a little out although it ties up pretty well with what I need to put in while refuelling.

 

 

 

The way that I manage the engine is that I increase the throttle setting in cruise until I get all or most EGT's below 700 C. That tends to have the revs in the high 2800's and the fuel burn between about 26.5 & 29 lph ..... and that all tends to give me an actual cruise speed of 118 - 120 knots.

 

 

 

As you can see in those pics, cylinder #2 is running at about 720 C while one of the other is below 600 and I'm going to take that up with the engine guys in Bundaberg. There are times @ partial throttle (say around 2400 rpm) that cyliners #3 or #4 run hottest EGT and #2 aligns with all the rest, so I assume that it is a fuel/airflow bias in the manifold at certain flows, but I'll speak with them about that in the next little while.

 

 

 

That's a bit long winded, instead of just saying "yes" to your question, but it might interest some 3300 engine owners.

 

 

 

Regards Geoff 2

 

 

[Guest brentc]

My fuel burn is all over the joint.

 

Flew from Tooradin to Bairnsdale return and burnt 18.5 LPH over 2 hours.

 

Flew from Tooradin to Mooruya and burnt 60 litres over 2 hours.

 

Similar conditions, similar throttle settings.

 

!

 

Yesterday had 3 pob at full MTOW 700 kg's. Climbout was 700-800 fpm at 100 knots, takeoff in about 450 metres and indicated cruise at 2,000 ft was a solid 120 knots, so tas slightly higher. Half the time I can't get that on my own!

 

 

[Guest ROM]

From your figures, brentc, it seems that Jabiru have some very serious work to do on their induction systems.

 

Airflow/ fluid flow does some very strange and very unexpected contortions ,when flowing at speed in a confined duct.

 

Very small changes in the velocities of the flows ie. RPM's, or even the starting conditions such as temperature and etc can change the characteristics of a confined airflow quite dramatically.

 

I had a very rapid and comprehensive education in the unpredictability of confined airflows when we got involved in designing and building a very large 400 hp cat engined seed harvester that relied entirely on suction; ie. vacuum cleaner type, to pick up pasture seed pods from the ground.

 

Also when experimenting with the air flow in the seed distribution heads on the air seeding equipment used for sowing crops.

 

It was quite usual for the entire high velocity airflow to flip flop from one side of the airflow duct to the other side with the slightest change in pressures or flow rates.

 

Around bends and curves in the ducts, the high velocity / medium pressure airflow would switch from one side to the other and actually leave a very low pressure spot part way around the bend just when you thought such a thing was impossible.

 

I would venture to suggest that this is what is happening in intake manifold ducting and maybe the exhaust manifold ducting on the Jab engines.

 

Compound this with the slightest change in revs and you have a different pulse pressure regime in the particular intake or exhaust manifold from the effects of the change in the timing of the valve openings and piston stroke rates which will either reinforce the inflow to a cylinder or act against the flow and leave a cylinder with a very lean mixture.

 

All in all, some serious changes in cylinder temps and fuel consumption figures are quite on the cards when design deficiencies lead to fluctuating manifold flows.

 

If I am right, Jabiru could quite possibly extract a lot more performance and better reliability from their current engine design by redesigning their manifold systems.

 

I believe that they may be working on this at present.

 

 

[Modest Pilot]

Was at the Jab factory a couple of weeks ago talking about this and that with Rod.

 

He pointed out that to get meaningful figures when comparing similar engines you need to get a Manifold Pressure guage. And yes it's O K in an L S A model!

 

 

[Captain]

EGT'S

 

As a matter of interest, during last summer when I 1st registered and started to fly the aircraft, the EGT's were all similar and No 2 fitted in close to all the others at cruise.

 

Then during the cooler months the EGT on No 2 read about 25 or more degrees warmer than the others (see the attachments in post #331 for a typical example) so the 1st thing I did was check all connections thru the intake manifold to make sure there was not a leak into No 2 (but I found nothing and the issue remained), and now it is warm again this summer the EGT of No 2 is back where it was last Feb/March and they are all nice and even.

 

Has anyone else found that?

 

On climb they are all about the same.

 

The only thing I can put it down to is icing on the outside of the intake manifold to No 2, (which is about the longest one) and I tried Carb Heat for a long period at cruise to try to change it, but it persisted every time with identical readings thru winter. Or perhaps a bias between the fuel flow between cylinders 2 & 3 where 2 gets less & runs a bit warmer and No 3 gets more than its fair share of fuel & runs cooler as per the photo in post #331 ....... but why only in winter?.

 

Can anyone offer any little gems on what might be causing such a change to EGT between seasons, on just one pot?

 

Regards Geoff

 

 

[Captain]

One year on

 

Just an update for those that may be interested.

 

I have been flying this aircraft now for a little over a year since it was 1st registered.

 

Only a little less than 50 hrs ...... but no issues or problems.

 

Regards Geoff

 

 

[Captain]

Progress Report - 50 hrs

 

On return from Natfly last Thursday I experienced my 1st little issue.

 

On a shutdown check I had a 150 rev drop from 2000 rpm on ignition 2.

 

Finally checked it out today and one of the plug leads had come out of the distributor cap. Easy to push it back after spreading the metal end bit a little and it clicked back in positively, so have done the same thing with all the others.

 

I understand that this is a bit common, so I suggest that any J engine owner check all leads in the dissy cap any time you have the lid off.

 

Engine showing 40.1 hrs on the mechanical HOBBS that runs off the Tacho and records all hours when the engine is over 1850 rpm.

 

The HOBBS in the Dynon, which shows all hours that the engine is running, is showing exactly 50 hrs while the Tach timer in the Dynon is showing 44.5 hrs which is the time with the oil pressure above some set point.

 

Did oil & filter change today, replaced all plugs and torqued all heads.

 

Heads were still all at 20 ftlbs as reported at the 25 hr checkup, except this time the 2 lower head studs on cylinders 3 & 4 needed a slight tweak, which is not unexpected as 3 & 4 CHT's run hottest.

 

Attached is a pic on cruise from the return from Natfy (just shows 115 knts as climbing slightly).

 

Hope someone finds the above to be of interest.

 

Regards Geoff [ATTACH]7689.vB[/ATTACH]

 

 

 

[Modest Pilot]

I had the same problem on one of the right side leads. The lead appeared to be a little on the short side, came out twice. I put an extra plastic tie to another wire close to the distributor, 100 hours and no further problem.

 

 

[bushpilot]

On return from Natfly last Thursday I experienced my 1st little issue.On a shutdown check I had a 150 rev drop from 2000 rpm on ignition 2.

 

Finally checked it out today and one of the plug leads had come out of the distributor cap. Easy to push it back after spreading the metal end bit a little and it clicked back in positively, so have done the same thing with all the others.

 

I understand that this is a bit common, so I suggest that any J engine owner check all leads in the dissy cap any time you have the lid off.

 

Engine showing 40.1 hrs on the mechanical HOBBS that runs off the Tacho and records all hours when the engine is over 1850 rpm.

 

The HOBBS in the Dynon, which shows all hours that the engine is running, is showing exactly 50 hrs while the Tach timer in the Dynon is showing 44.5 hrs which is the time with the oil pressure above some set point.

 

Did oil & filter change today, replaced all plugs and torqued all heads.

 

Heads were still all at 20 ftlbs as reported at the 25 hr checkup, except this time the 2 lower head studs on cylinders 3 & 4 needed a slight tweak, which is not unexpected as 3 & 4 CHT's run hottest.

 

Attached is a pic on cruise from the return from Natfy (just shows 115 knts as climbing slightly).

 

Hope someone finds the above to be of interest.

 

Regards Geoff [ATTACH]9149[/ATTACH]

Hi Cap.

 

Just worked my way through your posts. It's all very interesting, helpful and comprehensive. Please keep it going.

 

I have an indirect interest in J230, having just convinced a buddy to buy one; delivery late November..

 

Where are you up to hours-wise now? No further issues?

 

Cheers,

 

Chris

 

 

[Modest Pilot]

This has happened twice to my J230 and a J160 an our field. It's worth putting a few extra ties in the wiring harrness as well as spreading the connector. This spreads the load and seems to make them a little self supporting. Over 100 hours and so far so good.

 

 

[Guest Qwerty]

I'm told that a small smear of silastic on the OUTSIDE of the receptor on the Distributor cap will hold the leads in place. :thumb_up: