Last week we had a chance to do the final testing on the direct drive rear generator setup.
First: An overview of the system. It uses the John Deere style permanent magnet generator and regulator that the Corvair community has used for years. It is mounted on the rear of the engine on a CNC cut bracket. The drive has two pins which fasten in the Harmonic balancer “puller” holes. These pins have rubber bushings on them which fit inside a drive plate on the generator. This drive plate replaces the forward half of the generator pulley. This arrangement puts no overhanging, or radial loads on the crankshaft. The bushings in socket allow a minor degree of misalignment.
We have been running it for several hours and many may have seen it run at Corvair College #24 in Barnwell, SC. We had already tested its output but were not satisfied the results were correct. William Wynne stopped by and we wired up a series of head lights for load. I borrowed a very accurate (and expensive) inductive DC amp pick and meter from my father-in-law (Thanks Dad). We did several rounds of testing and verified each test with the meter and we calculated the load. We are happy with the results.
Here are the important numbers:
Engine RPM AMP output
850(idle) 1-2 (erratic output)
1200 3
1800 10
2850 20
The idle amp seems low and likely wouldn’t turn off the charge indicator light. Here are a few things to consider:
While we were running we tested the amp draw to the ignition system at full throttle. It used .7 amps! I later tested my Glasair’s facet fuel pump. It pulled just over 1 AMP. This is in line with numbers from Pegasus Racing’s Website. My radio and EIS only pull AMP. Modern lights don’t consume much either. The biggest thing to consider is that this type systems doesn’t regulate power output, it just burns the excess up and turns it into heat, which is dissipated through the regulators cooling fins. You don’t want to make much more power than you use.
We recommend the Corvair for day VFR Aircraft and feel this system will easily power most aircraft in this class. We will also be testing the 3 phase version of this unit which should produce 30% more power. The Panther 3.0L with this generator setup and the Billet 4340 crankshaft is being installed in Williams Vag-A-Bond for flight testing. Watch our website for availability and cost in the near future.
