SonexBuilders.net

Looks like someone is hot rodding the Jab 3300:

https://www.kitplanes.com/supercharger- ... +2022+%234

I like SuperCharging and have been thinking of doing this to my RevMaster.
Many years ago my partner and I developed a SuperCharger STC for the Diamond DA40. The setup, compared to a Turbo, is so very simple. The SC has it's own oil source and the SC does not create very much heat, just what comes from compression of the air. In the case of the DA40 there was not even a waste-gate or computer control. The Boost is all controlled with the throttle (pilot controlled). Simple

mike.smith wrote:Looks like someone is hot rodding the Jab 3300:

https://www.kitplanes.com/supercharger- ... +2022+%234

What could possibly go wrong by increasing cylinder pressure on an already suspect top end that is cooling critical?
Supercharger or turbocharger added power isn't free. There are consequences of added wear and pressure on parts not originally designed for boost.
Valves, rings, pistons and cylinder heads are asked to withstand non-tested stresses and nothing is mentioned about added weight in forward cg location.
The increase in performance sounds tempting as none of us ever have enough horsepower, however the realities of the application on this engine due to reliability and parts failure are not worth it.
JMHO
Joe

If I put a horse saddle over turtle deck, just ahead of the tail. my weight there might just provide enough counterbalance for that supercharger assembly.

David A

Jgibson wrote:

mike.smith wrote:https://www.kitplanes.com/supercharger- ... +2022+%234

What could possibly go wrong by increasing cylinder pressure on an already suspect top end that is cooling critical?...

Boosting HP at sea-level (120 ->141) could be a problem, maybe. But if Manifold pressure is capped at a reasonable level so as not to increase substantially the sea-level power, but then kept constant up higher (ie turbo-normalize but w/SC) the performance gains (8K-12K) are substantial while not pushing the engine all that hard.

The DA40 SC does not increase the rated power above the certified 180HP. But keeps that same sea-level power clear past 7K (the new normalized sea-level). So at 16K the plane is 15 knots faster and gets there much quicker.

However you can't compare Lycoming durability to that of the Jabiru. While the Lycosaurus may be 'old' technology, it is virtually bullet proof due to its robust construction.
Not sure what the compression ratio of the Jab is, but the Lycoming's is relatively low so the engine is much more tolerant of added cylinder pressure.
Even though Lycomings have valve and guide issues (as do most air cooled engines) those issues don't compare with the head, cylinder, valve and valve seat issues experienced by a 'newer' engine Jabiru.
The number of those issues along with the critical cooling issues that have been demonstrated in at least the first three iterations of the Jabiru is a recipe for destruction when combined with boost of any kind.
Altitude boost might be less stressful, but you have to GET to altitude hoping the 'software' and pop off valve both do their job.
When the Jabiru first came on the scene, I loved the engine and still think it would be a perfect engine for the Sonex.
However very soon it became apparent that they had top end issues before they accumulated a lot of flight hours.
Not very confidence inspiring for an airplane engine and apparently not so for a lot of early purchasers as they can barely give them away for fractions of their original cost.
Joe

Has anyone ever tried this? Have the marketed it yet? I’m interested in gaining even a little more performance
Al