coinz

9 hours ago, Wirraway said:

Well it has worsened.

As of a few minutes ago, down to 10 ads, including one hangar for sale, and one trike.

So only 8 aircraft.

so sad, been looking fir two years.

Maybe they're still selling 😃 then.What are you looking for? For me personally,if i'm looking out for something i put out a wanted ad,

always seems to work.

cheers

colin

16 hours ago, Yenn said:

I am still waiting for a replacement gasket, but in the meantime i have reduced the idling speed by turning back the adjusting screw 1 turn, On the test flight the engine stopped on approach, nose too high, revs dropped and suddenly stop. No worries i was high enough but started it and continued.

I turned adjuster up half a turn and next flight, it stopped again and being the lazy sod that I am, I said stuff the engine and landed without it. It started easily after I stopped, but i did learn something from it. There was about a 4 knot cross wind and as we slowed down it became much harder to to maintain heading, there was a very definite lessening of rudder effectiveness. So much so that I reckon with a real engine out situation I would not want to have to deal with a cross wind. The landing would be OK, but better brakes would be desirable.

When I get the gasket, if that does not solve the original problem I have an idling jet replacement. That was sent by Jabiru, when i ordered a needle jet. It seems for carbies I would be better off dealing with Flood than Jabiru.

We had 4 or 5 engine stoppages on approach with my early series 1 Jab at Marion field,idle was always stable on the ground.Eventually i discovered it appeared to be a design fault with the carb throttle lever arm.Throttle cable runs from left side of the engine and curves around the front then goes back to carb .My eng no high 600's later on they modified that. The carb throttle lever being alloy and the idle screw having a ball end and meeting the lever at an angle about 30 deg off from 90deg  meant the lever was distorting when snapping the throttle back on approach.

2 hours with a dremel had the lever and ball meeting at 90deg at the idle position and a small dimple in the lever(the lever is only 1/8" wide  so a bit underdone for the task) for the ball to always center itself on the lever . Eng never failed after that.

colin   

I use Caltex 98 from the same dealer,and he told me it is tested every 2 weeks,i have no idea what tests they do.He also told me it's the same fuel

as the Woolworths BP 98 up the road.

Colin 

PA28 no CSP,i was flying gave a slight shudder and i noticed EGT begin to rise.Mag gear had sheared apparently,nylon?i didn't get to see that.

cheers

colin

Looks like it could be doctored to me,at 0.46 left wing is just to the rear of cockpit and fin rudder 

suddenly is seen to forced to the right,even though the wing tip is lower than even the horizontal

stabilizer.It then miraculously returns to the vertical.

colin

@coinz Are you still running the KFM engine ?

 

Cheers,

Skelly.

No ,but someone else is,i found the Pup a little cramped.Sold it with spare motor.They are around,in hangers,sheds.Best thing is advertise under "wanted".

cheers

Last time i spoke to him it was flying,a few years back.

cheers

I've seen aircooled engs go from heavy oil usage to negligible by fitting a good modern ring package,and my series one 3300

i would say uses too much oil,so would be interested in a set of quality rings,care to share any information?

cheers

colin

My 230 is a 230B and i have the specific manual to suit,not sure of the difference to the 230C though,possibly throttle

as mine only has the single throttle and had a basic flaw in the idle stop mechanism which could cause (and did) engine cutouts

on finals.Cable runs right around front left side of engine and back to the carb.I see later model changed that.

BEW 350 kg.

colin

The Jabiru manual quotes 16.5 lph for the 2200 at 2800 rpm & 23.5 lph for the 3300 at 2800 rpm in a Jabiru aircraft. I get much better than that with my 3300A in the Sierra at low level (around 18-19 lph but at high altitude (7-9000 feet) it is up around 23-24 lph. I have never altered the jets so the carb is as it was out of the factory.

So what am i missing here?fair enough speed would be up but why has fuel usage gone up at 9000ft?

Coinz, 245F is too cold I agree. Was this the max on climbout? How was it measured? I have never heard of such a cold running Jabiru (or Lycoming) engine.

While I can't argue with the results, I can't see how any air which doesn't come into contact with the hot metal removing any heat. I imagine hot engine molecules vibrating strongly causing adjacent air molecules to be shot away, taking energy from the engine with them.

Please don't be offended by my questions, I am quite capable of being wrong. Gosh, it has taken me 20 years to get the 4 temperatures fairly equal in my old 2.2 engine.

Cruise temp,is now 255F.Don't forget air entering Ram ducts is travelling horizontally before being forced into a vertical path,you are assuming air is simply passing from one end and straight out the other.My assumption when initially looking into Duct,was if ambient temp is 15C and i'm travelling at 200 kph i want air travelling through the duct at 200 kph and at 15C,i don't want to slow it down and superheat it,by restricting the flow,i would only end up the same as these m/cycles with hot running rear cylinders.Of course this is only talk,i know that it is only theory but it helped.Exit area is ample in my Jab.

 

I believe that the plugs will always be black/brown running unleaded. Only grey if running leaded..

The colour of my chinese 4 stroke mower plugs is textbook perfect light tan,using the same fuel as the Jab.

We have had a load of waffle about Jab engines and the thread drift is going on all the time. Here is your chance to say what you "know" about Jab engines.

I have a 2200 Jab in a Corby Starlet, it runs well although I got poor mogas and busted a piston with detonation. Avgas is the go for me. I would like to try a different carburettor from the Bing, although the Bing runs fairly well.

Don't bother talking about the engine if you don't run one or regularly fly one.

I run my 3300A on 98,after modding the ducts it ran at a too cool 245F as i realized after 30 hours plugs were always black even after repeated

cleaning,did some carb tuning ended up dropping the needle and changing out the main jet temps have risen to 255F,after 2 oil changes using

Camgaurd am going to W100+ as recommended here,

the thing i don't get is why did Jab changed out all those cylinder heads seems like a lot of expense,when i could simply redo my ducts and end up

with a motor that ran "too" cool? Ducts,cut horizontally,lifted 15 at front,30mm at rear,extended at rear i can squeeze fingers into rear gap,aids

airflow to the rear,yes i have read all the stories on closing these gaps ,i disagreed then and still do.

Gaps between cylinders,i tried alu strips,yes they soon cracked,replaced those with extended fibeglass strips that were angled in and when set

hold in place by pressure.

Seems to me the ducting should have been better investigated.More volume and allow more cool air flow through too the rearmost cylinders.

Other issues i have with this motor,rocker bearing shafts appear very small diameter,rockers as far as i can tell have no spring to control side movement,

i can move the rocker sideways and easily hear clicking,i have 2 hours till next oil change,valve clearance check so i will investigate this more

thoroughly, but do these engines have any reputation for higher than normal rocker wear.I will back the adjusters right

off and check for bearing to shaft wear.Is it all the same in the Gen 4?,or have they gone to a hollow and bigger bearing area.

cheers

colin

Aeropup (SA) was sold to someone who started building them at Gympie,he had some fuse's build-up in his hanger when i visited.

He was advertising them in USD with if i recall correctly the Camit engine included.What became of it i don't know,

cheers

colin

CHT probe on no. 4.  I'd prefer the temperatures to be regarded as too low and inefficient than risk dropping a valve seat.  BTW I have been running a mixture control for almost 200 hours and monitor EGT and plug colour.

 

I'm with you 100%,a dropped valve is my biggest concern,and i'm only new to Jabirus and that has been brought on only through reading about that issue,and through personal experience with overly hot engines testing design limits.

Anyone know what uncowled radials run CHT wise,must have been pretty cool at high altitude,in minus temps.

cheers

colin   

I have often thought Jabirus would be better off with mixture control. Be interested how you did it and general operating procedures, rich or lean of peak at cruise etc.  

 

Probably no doubt mixture control would be an improvement but as Nev alluded too,who would know what's best for a Jab.The bottom of my 230's Fuse quickly browns after cleaning,i don't know if it's oil or rich mixture but it would be good to know it's not running too rich.The auto mixture is good,and easy to see why it was fitted for Recreational flyers but surely manual mixture control by somebody competent is superior.

cheers

colin

Most air-cooled motorbikes will overheat rapidly if they're not moving, as in sitting still, waiting for lights to change, or if you leave them idling whilst talking to someone. They rely on movement to keep the air flowing over the fins.

 

Most British equipment does poorly in high ambient temperatures, such as the tropics and Northern Australia. In fact, quite a bit of American-designed equipment also performs badly in those same conditions.

 

Yes i agree with the American HD's being affected too,i bought a new '86 evolution new,cruising back from Fitzroy crossing at 140k's arrived at Karratha

with a ticking noise from the rear cylinder,which it had from then on.This is probably what Bruce is experiencing,radiated hot air flow heating rear cylinder,i suggested he try increasing air flow that side but he was more into equalizing Ram air pressures,ie increasing pressure LHS to experience a cooling effect.

This has worked for me.  Move the oil cooler to the rear of the engine and duct air to it via a side naca duct (like carby inlet), reduce the size of the lower air intake that was previously there for the engine mounted oil cooler, built a close fitting duct from this reduced inlet to the sump. Max CHT less than 140 on the ground which quickly reduces to 110 for climb at 80 knots (700-1000 fpm), cruise CHT at 100 knots 105 degrees C.  I had a similar setup on my Corby Starlet and replicated it on the Jabiru. No need for cowl skirt or big mods to inlets.  I did add a bit to the cooling ducts to prevent air from going under the front cylinders.

 

105C at cruise is about what i see after a straight in approach and rolling out,at those temps i would imagine most all problems with Jab valves and

heads would never have occurred,and they may have gone on to rule the Recreational engine market.

Too high temps was the dirth of British motorbikes,i'll always remember back in the 80's while working in the Pilbara being told that "british bikes can't handle the heat up here and just burn up",seems Jabiru are the same and it's pretty easy to overcome.

Keenaviator,do you have individual CHT probes fitted?

colin

Still waiting for one of the "experts" to comment on this - As I understand (little to be sure) for air to enter, it must also exit. Effective air flow design must address both in & out let.

 

Yes,and i would be thinking of air exiting the ram duct,at the rear.I would be thinking lowering the pressure of the LHS even more,are you able to lift the rear of the duct 5 or so mm,to help more air flow into the front of the duct,thru less resistance at the rear.

colin

In situations like this they devise a fix that "works" structurally and that is then an approved process. There's plenty of planes that had doublers on wing spars etc.Sometimes they just keep an eye on it and drill a hole at the end of the crack to slow it up. Periodic checks are then done at intervals appropriate to what's happening with the crack(s).   The entire rear cabin bulkhead with door (the problem) was replaced on some high time DC-9 s... The weight of the engines  and the tail fin hangs off that part and it's a pressurised bulkhead. When it was removed the whole rear of the plane just flopped around in the breeze...Nev

 

I remember seeing plenty of cracks in company Partenavia P.68 wing,they were drilled and several, 4 or 5 strips were riveted across the crack.Plane was eventually slotted to  receive new spar.Heavy landings on these and C206's was prime reason for cracks so i was told at time.Maybe Virgin pilots have been drilled on this.

I use Caltex 98 in my Jab,only because i usually top up the SUV at the same time i fill the jerry cans.For some time every time i used Shell diesel

the motor developed a rattle (diesel rattle) and i'm talking some years that went on,if i filled with Caltex over a couple of tanks the engine would smooth out,

back to shell and the rattle would reappear,am i going mad or is there something behind this ??

Plug leads ended up inside my Ramair ducts was not initially planned,but these early ducts were very restrictive to airflow over the top 6 fins,

compared to D model, i wanted to keep them outside but the 90 deg spark plug caps ($146 for new set) were too short,so i routed them the same

as the later model . I would have used longer straight caps but they would have needed complicated sealing on an angle and removal would be near

impossible ,i imagine that would be an issue to be solved, Paul .

I've just done the opposite on my early ducts,cruise temps were 310F,so after some discussion decided to do some mods,now leads are 

inside like the later D model and cruise temps immediately dropped to 245F and been like that for 6 months.Interesting comments about the

leads sitting on the hot fins,will take a look and see if they can be held up out of the way.

cheers

colin

edited...mod

Can’t remember. But empirically speaking VNE is airframe stress related so I suspect it just remains the same. 

 

Speed quoted  at 150 kts would then be 10 kts into red zone if no airframe changes,that's all i was thinking.

How do they deal with the increased VNE?