Paul davenport

Thanks for the update. I had ordered my dremel grinding burs some days ago and will use them with the routing attachment to achieve the taper I want . Do you think we could have some pictures of under the cowl and of the fin mod. Do you think the fin mod was responsible for very much of your cooling success ?

Bares out what I found on the 230. One side on the 230 is more closed (pilots side) and number 6 is the originally monitored temp, when I opened up the plenum it immediately cooled. I to fitted ramps to the front openings and this helps . My engine cooling system is now a bit like grandpas axe had two new handles and a new head but it’s still the same axe. GREAT STUFF fellas keep it going

I have done the same to the heads but cannot find pictures.

Pictures of my drop in cylinder baffles. Last picture is of my cowl lip

Spotted this unusual cooling mod done to a (I think) Extra aerobatic aircraft, at Oshkosh had something todo with cooling but couldn’t find someone to explain it

I suspect but I can only find limited information on the subject, that the shape of the head cooling fins tapering from the base to the outer edge has a real effect on CHT. A mates 230 has rounded ends on his cylinder head fins and his motor cooled better than mine with out some of my mods ,and better after I made some mods to his. There is a real difference when comparing his heads to mine. When I get the chance I will modify the hottest head on mine and see if it has any effect. All aircooled motors that I have looked at (funny how you notice these things when you really look) have rounded ends to the fins. I have questioned Jab about this bit cannot get any definitive answers

In order to get my cht temps down on the 230 I discovered that closing up the air gaps only raised temps and in my case allowing the air to pass through the plenums by opening up the rear cylinders plenum ,allowed air to flow to the rear and by default cool the other cylinders. Also closing the large gap between the rocker covers with a plate making the travel down through the fins rather than sideways helped. I made plates that drop down between the cylinders on the crankcase side again making air drop through fins again carrying away heat and making the fins work to max efficiency, filling in the under barrel with butterfly deflectors reduces the volume of air that can carry away heat, it will however even out your temps raising cool ones . The exit ramp and opening size on my 230 were too small, modifying the ramp and increasing the opening size helped. It is indeed a black art

Many hrs of tinkering gone into getting it like this

Very interesting following your progress, and the question you get sick of answering when does it fly?.

T88 was no 8 on a 230

I suppose I should have been more specific and asked if any one has tried this and if so what were the results

Has any one moved the ignition leads from inside the cooling plenum chambers to outside the chambers on a 230 . Looking at the location of the leads they seem to block an awful lot of air flow to the heads

Slightly off topic but can anyone tell me the difference between gen 2 heads and ge3 fin wise . My mates gen 3 roller rocker runs cooler without any mods than mine did and I noticed his heads have more fins where the oil supply tube would be on the gen 2 this cavity is filled with fins

Hey what a combination of motor and aircraft. I will be in the states this year to go to oshcosh and we may travel down your way with US friends, any chance we could meet up and see your Avid

Hi Darren . I have an Avid mk4 with a Subaru motor in it, which is great but I need the stretched fuselage to balance it. I have added a ventral fin to stop it wagging its tail, which with lighter engines it does not do . If you didn’t know these aircraft were really only designed for a light weight engine like the 582 and when kept light have an amazing stol performance. I have owned mine now for 15 years and love it, BUT if I were to repeat it again and after seeing what the 2200 Jabiru engine does in this airframe I would install the jab engine. As a tail dragger it is a real handful as mine is set up ,I have ground looped mine only once(and believe me that was enough) with lighter engines it would be better, good luck and keep in contact

You can park it in my hanger any time you like. Flew on in Shepparton once with Peter Harlow from memory it was well balanced

Very nice. Mates father had one and loved the full fine decent rate

And what is a sporty ? What does it look like? I would like to know what difference it would make to my j230. Spending up to $13000 to find out it’s ,not as good as the sales puff would hurt

And how much improvement on a fixed pitch was it

Has any one fitted one to a 230 . What were the results

An Air Master inflight adjustable pitch prop was fitted to a Brumby powered by a 912 and OKed by factory with spectacular results. Better climb rate and a 15 knts increase in cruise speed . The owner is very happy

On the 28/04/18 at Porepunkah airstrip we will be hosting a flyinn movie night . Camp over night under your wing or in the hanger and enjoy a movie or three with fellow aviators at the foot of mt Buffalo . Tea that night provided . Breakfast next morning and fly home ring 0408057837 for full details

Just back from a 1hr flight ,ground ambient temp 28c engine temp at 6000 ft 122c at 2700 rpm. That was the hotest cyl all the others ranged from 100c up to 122. Temps went up at 2800 rpm but only to 127. On climb temps all under 150. Not bad for a 6 cylinder j230

So those numbers are your best on a cold day or normal summer time temps ?

Does having the high tension leads angled up or down off the spark plugs have any effect on CHTs