Aircraft Supercharge 13B engine - Need help determining how to flow parts

[Fir]

Hello,

I have been building up a 300+ hp P-port boosted rotary engine for my aircraft. Everything from the bare block outwards is custom. This engine is designed to be able to provide full power up to 18K feet. I would like to verify and enhance the air flow in the rotary housing intake and exhaust ports, butterfly throttles, carbon fiber manifold, air box, intercooler and supercharger. I have a 90mm dia. Lightening MAF sensor as well as a MAP sensor to be mounted after the supercharger and before the airbox. Air source could be the actual ROTREX supercharger I will use connected to a speed controlled (invertor) electric motor. I am stumped on the best way to flow these parts both individually and as a system though. Simple flow bench? Custom flow bench? The MegaSquirt Forum (my engine controller) provided a EXCEL spreadsheet of the flows verses voltage outputs of the Lightening unit but I suspect their calibration data is system dependent. Any advise on how to use the parts I have would be very appreciated.

Doug in Japan

[Flash]

When you say 13B i can only assume that it vary similar to the RX7 eng.

What make porting so crazy with a rotary eng it that any opening of the port, next to the rotor will be like enlarging the Valves and cam lift(rotory engs have nether of theses) and any porting on the edge of the rotor opening will be like using a high duration cam.
Many a years ago i new if a guy that had a 12A ported, and it would turn 10,000 RPM.
I know this isn't much help, but that's all i know.

Have been running thru my mind, how you would hook a flow bench up to one of these Engs :;):

[Fir]

Flash,

Yep its a Mazda 13B but the P- ports will be ground by a pro and kept boringly tame. Nothing radical like you see with the 10K+ rpm dragsters. N/A with a tuned manifold 120% VE is possible at mid and higher rpms. My prop limits engine rpm to 8200 max. That is slow for a rotary as the piston rotor revolves at 1/3rd that speed. The RX-7 engine put out 280hp stock with a small T-3 turbo. I am running E-90 with Bosch pencil high flow injectors right in the housing so 300hp. will be a walk in the park. The boost is there mainly to allow the engine normal operation at high altitude. My main interest is to document my work as well as to insure the ports, and intake tubes are flowing equally. I hear guys that grind rotor housing do test them on a flow bench with inclined water manometers, but I would like to capture all data in digital form.

Doug in Japan

[thomasvaught-1]

I would be VERY careful when using the Rotrex Supercharger
with very much boost. The "Planetary Gear" set-up is actually
a group of 3 rollers traveling around a small shaft and a large
drum to give a ~ 10 to 1 step-up ratio.

The units are not capable of large mass flow without galling the small shaft. The old Paxton Supercharger with the "Planetary Ball" drive suffered from the same issues.

When the unit galls you pull over to the side of the road in a car. If it galls in an airplane at high altitude: no boost, no power to compress the air, not enough air density to keep the engine making proper power, you fall out of the sky.

JMO

Tom Vaught

[Fir]

Tom,

Thanks for your concern. The engine is N/A configured. The supercharger is a 'plus alpha' device, ergo not flight critical. If engaged, the plane can reach flight levels of 25K feet but the engine won't be putting out its rated 300Hp. It doesn't need to. Long distance flights are commonly flown at power settings from 50% to 75% to lower engine stress and improve range. This is a research engine I am working on now and it won't be flying anywhere until it has spent at least 200 hours of prop dyno time. I would be very interested to contact anyone who has had a failure with the ROTREX SC to find out why. I have personally gone to the Copenhagen factory and met with the engineers who designed it. Unlike the Paxton SC ball bearing point device, centrifical forces create a gap between the traction rollers at speed and proper temps. In operation the momentary compression of the oil plasticizes and provides power transfer between the components. The only way I can imagine galling the central shaft is by forcing it to high rpms before it is warmed up to the proper operating temp. The other failure mode would be letting the oil get to hot and then excessive thermal expansion would probably cause slippage. Every mechanical device has its lubrication design limits. Aeronautical engineering entails down grading component use potentials to ensure better reliability. I am not expert in tractor pulling contests but I would suspect the opposite is true. Full steam ahead. :laugh:

Regards

Doug

[thomasvaught-1]

The engineers and the marketing guys came to visit me several times at the Ford Research Lab. I was given three units to test.

They "pushed" the concept for several years, finally fired the marketing guy, and moved on to a job shop that did work for GM.

They always said you needed the oil pump to keep the oil with-in the temperature range that the unit could live at.

I have not visited their factory but I have been to Garrett, Borg Warner, Turbonetics, Vortech, Paxton, Eaton, etc locations.
I have 34 years of Boosting experience and 31 years with Ford doing the job there.

Just trying to keep you safe. The larger the wheel the more air power the unit transfers across the roller system. At some point the rollers slip. If you have a small unit with a low air power you may never get it to slip.

Tom Vaught