New RDM PSRU

[rv6ejguy]

New PSRU photos were posted on Flysoob today. This unit is being developed for higher hp automotive conversions and uses an internal spur gear setup. Can drive a hydraulic C/S prop governor and has a pad for driving standby alternator.

"General description: 8 diametral pitch, High-contact-ratio internal
gear set with oil lubrication and cooling.

Propeller Flange: "Continental" style F-flange per ARP 502

Distance from the prop flange to the PSRU mounting flange: 13.22"
Prop flange is 1.790" above the crank.
Prop flange is 0.741" to the left of the crank

Rating: 400 hp continuous for 2000 hours

Reduction Ratio: 2.29:1 with a 24 tooth pinion and a
55 tooth internal gear (designed to accommodate other ratios as well)

Alternator Flange: Pad for AND 20010

Starter mounting: Accepts standard Subaru automotive starter: 9 tooth
pinion, 124 tooth ring (modified 2.5 module metric)

Weight: Estimated at less than 75 lbs (with starter, governor, and
alternator)

CG: 4.83" ahead of PSRU flange"

"For the 250HP and up market I think the hydraulic governor will
be a necessary feature. The governor feature will be there for those
that need it and we have worked with a propeller/governor vendor
to spec a governor for this application. All prop/engine combinations
will be ground-tested and have TV studies done. We have already
arranged for this. The design of the drive included handling torsional
vibration via carefully calculated shaft sizing to store the energy
and release it (torsional windup), not dissipate it. The model was
based on the rotational inertia and masses off the EZ30R motor. For
the alternator, it is just a drive for the B&C SD20 with internal
shear coupling. The psru will be ground-tested with various prop
combos. Initially we have an AeroComposites, composite Hartzell ASC
II, and a metal Hartzell 3-blade to generate our TV data but will be
testing others. The test-stands are also instrumented with load-cells
so we will also get hard data on static thrust, torque, HP, etc in
addition to the TV data."

Like I've said before, better products are coming into this market all the time. More science and less "eyeball engineering" is a good thing. Flight testing will be done in the US and Holland.

[pierre smith]

.....yet, Ross. Will it fit the V series..V-6, V-8?

Thanks,

[rv6ejguy]

Flight testing has not begun to my knowledge so I think pricing is a ways off yet. It won't be cheap. Not sure what the plans are for adaptation to V8 engines.

EPI and Bud Warren already produce reasonably well proven drives for V8s which are in the $8-12K range.