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What? 18mm thread is the standard Lyc/Conti size, Jabiru plugs are 12mm. I think the short adapter from ACS is a multi-thread that may fit also the Jabiru , it looks like several different dimensions, but if you chose the longer model, look for the 12mm version.

Thanks for your input guys,, I am well aware of these concerns, and has been in discussion with Airmaster, Woodcomp, and GT about this for about 2 years. The Airmaster with Warp square tips I recall is somewhere around 6000 kgcm², GT is 4350 and Woodcomp 4600. I think the Airmaster AP420 using the Sensenich blades will still be well above the 3000kgcm² limit. The MT 3-blade cs prop, which Jabiru have also approved, is about 5000 kgcm² I turned down the ideas of the Airmaster, as I am not very confident in the Sensenich blades, I already have the paintcracks described in their sb after less than 100h, and I am also not happy with the static/lowspeed performance. This info I got from Jiri Holoubek at Woodcomp: “I comunicated this problem with Mr Rodney Stiff from Jabiru company . The Jabiru company allows the propellers with polar moment up to 0.3kg/m2 ( for the Jabiru 3300 ) normally. The on ground adjustable propeller - type SR 200J has the polar moment 0.41kg/m2. Mr Stiff extended the polar moment to 0.5kg/m2 for our propellers. The SR 3000/2JM is 0.46kg/m2” As it is wood/glass blades there is a lot more structural damping than the sensenich carbon blades, same construction as the MT which is approved. Regarding the loads on the crank, there should be no significant difference between a MT and Woodcomp with similar polar moments, but it’s more important with dynamic balance on a heavier prop and I will certainly do a balance run as recommended in latest Jabachat. From the discussion about props in Jabachat, and that they approved the MT after extensive testing, my conclusion is the inertia limit is probably not a real design limit, more that Jab has not enough own test data to approve other than 2 blade wooden props. Anyone know more about this?

At the bottom of the Bing carb, right below the butterfly, there is already a connection for manifold pressure. It's blocked with a small screw, just take it out and push a 5 mm ID tube on. Look in the tuning service bulletin JSB 018-2, on page 5 there is a cut drawing, showing the MAP sensor port as #51.

Facthunter, it looks strange also to me with a common natural frequency for the 4- and 6 cyl engines. Making a pure operational note as “do not cruise or climb” in the propeller selection chapter of the installation manual, with no further enforcement in the operation or limit sections of the op- and maintenance manual is also strange! As we are going to change our present Sensenich carbon ground adjustable prop for a Woodcomp SR3000/2JM (electronic constant speed, 2-blade wood/composite), and this prop have a higher inertia of 0,46 kgm², i let a friend of me, who is specialist in vibration analysis, make some brief calculations based on the dimensions of the 3300 crank, estimated inertia of the flywheel and Jab’s inertia limit of 0,30 kgm² for the prop. He found lowest natural frequency for torsion of the crank to about 580 Hz, lowering to 500 Hz with prop inertia 0,46. Natural bending frequency of the free prop end with 2” extention and the heavier prop was about 380 Hz (assuming same stiffness for extension as for the crank), somewhat lowering due to gyro moments (not calculated). As the max initiation freq of the engine is 165 Hz (3300 rpm, 3 ignitions /rev), we don’t think there should be a torsional resonance problem at all, and for sure the 2100-2400 range can’t be based on torsional natural frequencies. Please observe these calculations are based on some assumptions, intended to find out if the given rpm range could be based on resonance, and then calculate a new range for the heavier prop, and may only be used as an indication. I think the flywheel bolt problems has to originate from loosing friction force, i.e. clamping force. In the old design with steel bolts in steel crank, clamping alu flywheel it’s easy to understand, but the current design where only steel parts are involved, this should’t be a problem, right? Regarding the prop inertia limits of 0,25 for the 2200 and 0,30 for the 3300, my calculations give the same max torsional moment using standard torque curves for even firing 4- versus 6 cyl engine, so the designer seems to have some concerns about max torque in the crank.

Harmonic rpm range? In the installation manuals, section "Propeller & Spinner" or "Propeller selection" it is mentioned "Do not cruise or climb in the range 2100rpm - 2400rpm". Same in 2200 and 3300 manuals, new and older editions. In the Instruction and maintenance manual I can find no reference to this. Is this a harmonic rpm range? At least I interpreted it so and made it yellow range on the tach. Anyone know more about this?