J230 @ YSWG

[Captain]

Looks nice. Isn't it interesting what each individual chooses when they have the chance to play with a dash layout and colourscheme.

 

It'd be boring if we were all the same, wouldn't it.

 

I note that it looks like that dash has the GPS antenna on the outside. Is that what it is up front behind the screen?

 

????? 1 - If so, does anyone know whether GPS signals have any trouble thru vinyl .... as it has noworries with fibreglass & perpex so I was going tomount mine inside the panel just under the glass. If nobody knows I'll have to do a test later this week.

 

????? 2 - Also does anyone know whether there is any problem mounting a UHF antenna below the aircraft, behind and within 150 mm or so of the transponder antenna ?????

 

Regards Geoff

 

Captain

 

 

[Guest Roger]

Geoff - If you sneak up on me in that thing I think I would die of fright! I really hope we can get both our machines to WoverW, although we have a scant five weeks to make it happen (or jabiru does in our case) :confused:

 

Clem - I see that you have the new smoking version of the J430 - ciggy lighter in bottom right hand of panel ;)

 

Roger

 

 

[Guest Fred Bear]

I said that to the builder myself when I saw it. He pulled out the lighter and showed me that it had been disabled. I think he wanted the 3 knobs to look the same size which is why he just didn't plug it with one of those no-smoking plugs.

 

 

[Captain]

Muffler & final pipe have been sent off to Jet-Hot Coatings for ceramic coating in an attempt to reduce the temp inside the cowl .... but have decided not to unbolt & send off the 6 headers although their surface area is probably greater.

 

Will post a before & after shot when I get it back in a week or so for those that might be interested in this. Ian McPhee tells me that it made a big difference to his aircraft.

 

Doors and other minor fibreglass items have been undercoated and have had an initial rub back.

 

As you can see from those pics .... I also have a wing up ready to start work on it, so that's another little milestone.

 

Have hit the wall a little this last week, seem to be doing lots but getting nowhere. Oh well. Onward and upward ... hopefully.

 

Captain

 

 

 

 

 

 

 

[Wilfred]

Re GPS Antenna

 

We have the GPS antenna on the dash and it works like a treat

 

 

 

[Ross]

When I do my flying in the Jab 55-3917 at Griffith I sit my old hand held Magellan GPS 320 on the passenger seat and it works fine.

 

It wasn't much good on a trip to Wagga though in one of the back seats of a GA singlewith no sign of any composite material in its structure.

 

Regards Ross

 

 

[Guest Fred Bear]

Oh, so you haven't started your wings yet Captain?

 

There's probably a week ortwo in them. They can be a little tricky. You will find that the instructions will be old, from the J400 model and there may be two spots to put the inspection plates, and the way it's marked you'll find it seems like they want you to cut into a wing rib - don't!

 

Gee... that deadline is getting close and without the wings being worked on...

 

 

[Ross]

I am dreading the wings on my J160 as so far all the draw strings in the fuse have been useless as they have been epoxied to the structure. I got around that problem by using a piece of wire and a narrow diameter fairly flexible piece of pvc conduit which I removed after threading the new draw wire through it.

 

I also note that the wing draw strings with their paddle pop sticks attached are hard up against the inboard end of the wing with no free stringat all making it more difficult to attempt a clearance of the string.

 

One party told me that their draw strings were also uselessso they cut an extra hole in the wing to get access to pass the aileron cable around the bend to get to the outboard aileron anchor point.

 

Regards

 

 

[Captain]

I knooow Clement, my son, I knooow.

 

Did I say I'd have it ready for Wings-Over-Wagga 2006 or Natfly 2007 ....... or maybe W-O-W 2007?

 

And if I don't make it for the end of next month, Roger will come over in his new 230 and go nah, nah, nah, nah, nahhhhh, and then refuse to take me for a ride. You know what those rich bokes are like that buy factory built aircraft

 

Have decided that I'm going to put in some long nights next week, so am plucking up the courage to tell my wife that she will have to abstain until the wings are done.

 

I'll start hacking into my wings next week Ross so will give your a draw string report .............. or you'll hear me swearing in Leeton if they are not OK.

 

I also need to pull cables thru for the wingtip strobes, so we'll see.

 

Peter ... Why didn't you put your GPS antennainside the panel?

 

Best regards Geoff

 

Captain

 

 

[Captain]

Have just done a test to try to answer my own question on GPS antenna location .... as I have the same antenna in a Sailplane with the unit mounted inside a carbon-fibre instrument panel under a plastic top and it works well.

 

I set up the Avmap antenna and recorded the SPS signal strength, then covered the antenna with 3 layers of vinyl and 2 layers of fibreglass. The signal strengths dropped less than 1 point and as you would know they vary all the time anyway.

 

So my conclusion is that the antenna can go inside the panel out of the directsunlight and it should work fine.

 

Decision taken.

 

Regards to those who might be interested Geoff

 

 

[Ross]

Hi Geoff K & Clem & Turtle

 

I know how you feel about that target disappearing into the distance.

 

At the moment I am doing the jigsaw puzzle of the cabin lining. Apparently the lining pieces were designed before the cabin reinforecements were introduced into the J series and the header tank under the passenger seat. As a result you have to think of where will the bits fit assuming there are no reinforcements. Of course they don't fit exactly so you have to cut holes in them and trim bits off here and there and also overlap them in some places and not in others. I was never very good at jigsaw puzzles. Apparently cabin lining does not include the top of the instrument panel or anything behind the seats except perhaps the sound curtain although it is separately listed.

 

I can't really do the firewall lining (foam & felt) without installing the engine again to get all the firewall holes done before applying the foam and felt. I tried drilling through felt on the back of my second hand office chair once. I don't think I will try that again.

 

Turtle's panel doesn't seem to have much room left on it. Mine is strictly VFR but I would like to install an electric compass and a 295 or a 296 but that rapidly escalates the cost.

 

Turtle is starting to rub it in a bit!

 

Regards

 

Ross

 

 

[Wilfred]

Just a couple of thoughts on panel layout as i see it.

 

The main problem with the layout as pictured is the location of the transponder and radio.

 

If in controlled airspace where you have a fair bit of radio work it is allmost impossible to see the frequencies without sticking your held down.

 

Not a problem if you have a passenger to hold the stick but a pain in the proverbial trying to hold altitude & heading and see the radio.

 

Other than that fine

 

Doing it again the radio & transponder would be on top of the GPS.

 

The GPS can easily be angled for a better view.

 

 

[Captain]

You are spot-on Peter. That was pointed out to me by another illustrious member of this forum, and that's why I located my radio & transponder at the top.

 

Ross ... just tell her those items are each $50 on special at Aircraft Spruce and go for it. That's what the rest of us do. Some of us having beengetting away withthat for years with our toys ... and it's not really a lie when you have your fingers crossed and get her some flowers or something of equal value to your purchase ($50). Captain

 

 

[Ross]

I would agree whole heartedly. When flying the Griffith factory built Jabwith the radio at the bottom of the panel it is a real pain keeping track of the frequencies with your head down, not a good idea, and changing them. Howeverthey could all be preset in memory for a particular trip requiring just a flick of the switch to get to the next required frequency.

 

Some radioscan have a remote button on the stick to cycle the preset frequencies. I haven't checked to see if this is available on my Jabiru supplied radio.

 

As turtle points out ithe radiois probably, even for VFR pilots once airborne, the most adjusted instrument on the panel. So it does not make ense for it to be mounted at the bottom of the panel. I have moved mine up a bit and if it is not OK then I will cut another hole and make a patch to fill the gap.

 

Regards

 

 

[Ross]

Geoff

 

I can see that I have not been keeping up with the necessary strategies to really nail this project.

 

 

[Ultralights]

i wonder how much performance would be gained if the Exhaust system was designed for optimal efficiency??? the 3 pipes into the barrel

 

muffler dont look like they would help performance in any way whatsoever.

 

has anyone done any work in improving the exhaust for max efficiency?

 

 

[Ross]

There are many considerations in engine design one of which is the back pressure of the exhaust system. It can havea big effecton the oil consumption of the engine. The more back pressure the less oil consumption and the less power from the engine. I used to wonder why the older aero engines had such a copious appetite for oil on engines with no mufflers and straight out exhaust pipes and no aircleaners compared to typical land based engines.

 

So Jabiru have at least two factors that reduce the power from the engine. The first is an air cleaner that is even still in use when carby heat is applied which must cause some reduction of air in the firing cylinder. The second is some back pressure from the exhaust system.

 

Both of these items will probably contribute to a longer engine life and a reduction in oil consumption and a reduced running cost.

 

Jabiru and other manufacturers areobviously continually researching their engine to get more power from it aside from the normal targetof enhancing its mechanical life and reliability. There have been a number of changes to the oil pump and the oil cooler for example aside from other engine changes and improvements.

 

For example fuel consumption with the Jab 2200 motor has supposed to have dropped from about 16 L/h to about 13 L/H due to letting the engine run leaner and hotter therefore more efficiently. They have increased the quoted HP from current models of this engine to 85 from the previously quoted 80 for previous models and have raised the TBO for a bottom overhaul from 1000 hrs to 2000 hrs with a top overhaul at 1,000 hrs.

 

 

[Captain]

Good post Ross. When you look at the cost of the engines, the hours they now achieve and the number in service + the cost of a refurbishment, I reckon that they are bloody good value.

 

I think that the latest 3300 engines have matched length header pipes which I THINK is an update. Can anyone look at mine in the pics and confirm that? If so, Jabiru have refined the exhaust system somewhat, and from my limited exposure to the 6, it works pretty well, routinely.

 

In reposnse to Clem's note about the wing inspection openings, I have just been out in my shed tonight getting up to mischief with a bright torch. With the lights out you can see right through the wings with the torch below and the Jabiru's cutout marks look to be in the right spot and outboard of the rib.

 

If you haven't already, Ross, I suggest that you have a check using that method before you cut. Let me know how you go.

 

I have also tonight done the holes in the fuselage for the Transponder antenna and the UHF antenna.

 

Also did a heap of laser alignment checks now that the engine is on etc and it all came up spot-on .... which is nice to know, what with the offset of the engine mount and the engine itself.

 

Regards Geoff

 

Captain

 

 

 

 

[Ultralights]

i was thinking a little more than back pressure, but more along the lines of pulse tuning the exhaust.

 

i was playing around with the exhaust on my motorcycle, and even a small change such as rerouting the exhaust has had a significant effect on performance! the bike is an inline 4 cyl, 4 stroke engine.

 

after a bit or research i found the length of the header pipes are tuned so that the exhaust gasses passing the junction will creat a

 

venturi effect in the header coming from the cylender with an opening exhaust valve, helping in removing exhaust gasses and the iduction of the next charge, then it will produce a pulse that will stop the exhaust gas flow temporarily and creat positive pressure as the exhause valve closes, stopping the fresh fuel air charge from entering into the exhaust and staying in the cylinder.

 

when i rerouted the exhaust from beside the swing arm, to under the seat, i added about 2 inches to the exhaust pipe length before it

 

enters the muffler, this small change has resulted in almost no power at full throttle at engine speeds below 12,000 rpm. but once

 

engine speed was over 12,000 rpm, then full throttle could be opened and the engine produced power as normal. the extended exhaust

 

sytem also reduced fuel economy significantly. consumption went from 4 ltrs/100kms to 6ltr/100kms

 

i put the exhaust system back to original, and the engine produced power at full thottle at all engine speeds up to 19K rpm. and economy returned.

 

changing the muffler between standard and a free flowing one made no difference to power output at all.

 

with the modified longer exhaust, i tried adding a resricting plate to try to regain the lost backpressure, this had no effect at all.

 

it was this learned knowledge of the way the various lengths of header pipes directly effect engine performance, and noting that the exhaust header pipes on aircraft engines, which seam to have no obvious designed length, that got my curiosity as to why this doest appear to be high on the design priorities of aircraft engines and if any performance can be gained from properly design exhaust headers??

 

not just in producing or controling the amount of back pressure to control oil consumption...

 

 

[Guest Fred Bear]

I take it that they have fixed the wing inspection ports - lucky for u. I was checking one yesterday and the port is in the wrong spot completely.

 

Looking at your exhaust you definitely have the latest with the 3 in 1 system. Better than the old ones with 1 pipe into the muffler and less restrictions on yours.

 

You'll need to use that laser unit for your wheel alignment if you can work out how to adapt it - yet another job for you to do. They all add up.

 

Good idea putting the radios at the top. The factory Jabs are having the radios fitted at the top of the dash these days.

 

One day soon it will all come together and it won't take long to finish it all off. You will reach a point and realise that it's almost done.

 

Hopefully the wings don't frustrate you too much.

 

There is slack in the draw strings in the wings, so just break the paddle-pop stick and you'll find the excess, join a string or 2 on and you'll be on your way. Pretty simple stuff. Hopefully your supplied cables are long enough for those massively long J230 wings. You will also have trouble reaching the strobes from the inspection point when mounting them... good luck with that one! PM me for specific info on that one.

 

There is a light at the end of the tunnell, although I'm confused and it might be a laser beam, I can't tell.

 

 

[Ross]

Hi Jabbers

 

Thanks for all that useful info on draw strings, wing cut outs and exhaust systems.

 

If we quoted serial numbers with this detail it would give us all a bit more information. My J160's production numberis # 014 and the engine number is 22A 1906.

 

So I just got the new carby jets I think (I will have to check it) but not all the oil pump modifications but I get the new oil cooler. I had to install extra cabin reo along sides of the windscreen and from the whalebone across tothe door frames. My rudder cable holes were not installed making life a bit confusing. I think I have the modified UC axels and the old style round discs on the brakes which might turn out to be an advantage. I had tomodify the passenger seat top to install the new header tank which came with the kit.

 

Regards

 

 

[Captain]

Had a break over this long weekend after finding, on Friday, that the super-duper etch primer and undercoat did not bond well to the perpex around the windows.

 

Bugger.

 

Have had to take that all off around the windows and redo it with perspex suitable stuff.

 

Now have the fuse masked up again & ready for final thin coat undercoat, hopefully tomorrow morning if the wind stays down .... and the plan is to final coat the fuselage next weekend, so have booked the best spray booth in town for that.

 

Started on the wings this arvo and have the 1st stage done on both of them.

 

Am about to go out to dinner tonight with our Accountants, who flew down today. I hope they don't ask how much a J230 costs. Might have to see if the "50 bucks" line works with them.

 

Regards Geoff

 

 

 

 

[Guest AusDarren]

Bit of a disapointment about that Primer after getting it from Germany and all...

 

Hope its not too much of a setback..

 

with WoW fast approaching and all..

 

Good Luck,

 

AusDarren

 

 

[Captain]

Final undercoating of the fuse was done this morning. Nice result and not one blemish to be seen, except where a couple of local blowies did the 2-step before it dried. It will all come out nicely in the final sand.

 

Not a pin-hole to be seen.

 

The Holden Blimp is in town again today. Did they take over at Holbrook again Don?

 

Not much will be done on the J for the next couple of days as I have to get the Sailplane ready for its Form 2 for the next couple of days.

 

To be ready for W-O-W is all but impossible ... well this year anyway.

 

Regards Geoff

 

Captain

 

 

 

 

 

 

[Guest danda]

Geoff they where here today however I have been so busy that I haven't been out to the air field but like all these things I guess I'l soon find out. The truth is I loveto see the thing in the sky as I was returning from Albury today it was in the skyandthere where a lott of cars who went off onto the gravell not watching what they where doing quite funny at times.

 

Don