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  Plane-Power 70 Amp Alternator Install Pirep


28 July 2022 News Flash:

On 25 July at EAA/OSH, I spoke with Plane-Power Support Rep, Allen Buffkin, who stated that Hartzell/Plane-Power have in development a one-piece machined mount to replace the welded bracketry that has been failing on many Beechcraft Bonanza engines. This new mount will only fit the TCM bracket PN: 628004. Hopefully, this will finally put an end to failing mounting brackets on Beech airplanes.

Allen also stated that they have alternator and generator replacement kits that now fit the original factory generator mounts, which presumably have survived the test of time on many airplanes. Click HERE for a link to their STC Approvals page.

Allen has agreed to provide his mobile number for anyone needing more info on this or other Plane-Power questions: (334) Three-Hundred  Six-Eight-Five-Nine.



OK, all you folks with Bonanzas with generator set ups and puny 50 amp alternators, check this out if you are looking for more juice to run your fancy new panel stuff or to stop brownouts during night ops with your incandescent taxi/landing lights running.



Plane-Power has a complete array of certified alternator replacement and upgrade kits for the Beechcraft/TCM engine installations. Check out Aircraft Spruce for pricing! 



Generator to Alternator STC Model Eligibility HERE 


IO-470N Alternator/Generator IPC Extract HERE


Gear Driven E-225 Series Fit Guide HERE


Check Out the Bracket Failure Pireps Below



Here is an install pirep from Stan S. the Bonanza man with an IO-470N:


We finished installing a new belt driven 70 amp Plane Power alternator on the IO-470 in the Deb today. It comes with a new mounting bracket, new stabilizing arm and belt tightening bracket. Everything fit perfectly. The Plane Power 70 amp alternator weighs 10 pounds, the same as the 50 amp InterAv alternator it replaced, but it has a state of the art small voltage regulator that replaced the InterAv's voltage regulator, over voltage relay and huge capacitor. The Plane Power kit also comes with an "ALT INOP" 100 milliamp warning light that must be mounted on the panel in the sight of the pilot and connected to a power source through a one amp fuse or breaker on one side, and to a terminal on the voltage regulator on the other. 


We fired up the engine to test it and put about a 45 amp load on it, and at 950 RPM it held 14.1 volts. The staff at Plane Power told me this alternator will deliver 70 amps at cruise RPM. Note not all 12 volt Plane Power alternators are 70 amps, the gear driven alternator that fits on the E series engines is 50 amps, and they also have some 60 amp models. If you have a belt driven alternator or still have the belt driven generator, this is a good option to upgrade to current technology, and I like the warning light that will illuminate if the alternator goes off line. Another Beech Boy recently installed the gear driven Plane Power alternator on the E series engine in his E35, replacing his old 35 amp generator, and is very happy with it, also. 


Picture of the installation attached, when the picture was taken we were not finished tie wrapping the wires, etc. The Plane Power alternator is physically smaller than the InterAv alternator it replaced, but weighs as much, 10 pounds, versus 17 pounds for the old 50 amp generator we removed about 7 years ago. We replaced the InterAv alternator because it failed, bad bearings probably resulted in physical damage to two of the three field/armature components or the brushes/commutator, it would only produce about 15 amps and upon removal the bearings were obviously worn out, the shaft had about 1/4 inch of end play.

We also replaced the drive pulley on the engine, the old one was a little dented. That job was a little tricky, using a puller to get the old one off and driving the new one on far enough to get enough threads on the shaft to move it the rest of the way on with the nut. Not much clearance back there, but far more clearance than Cessnas have!



35-A33 KSAC


Here is Stan's Plane Power Install





The IO470 engine is known to dish out quite a bit of vibration.




IO470 owners continue to experience bracket failures through bracket Revisions, J, K and L.


HERE is a thread on Beech Talk going back to 2014 regarding Plane Power IO470 bracket failures.

The above picture is from David F. and here is his pirep on his experience:

" our case the mis-alignment at the green arrow was so severe (3 mounts so far) that it stretches the weld apart (the red arrows) causing the cracks. We re-welded our bracket and relieved the holes to achieve correct alignment of the bolts, correct alignment of the belt, and so far everything is working.

Our last bracket cracked within 10 flight hours before correcting the mis-alignment."

Below is a Plane Power bracket that lasted 85hrs before failure on Daniel K.'s K35 Bonanza.


N35 Owner Pedro G. says:

"Im on bracket #9: changed engine mounts, balanced prop, shortened alternator belt, made sure bracket went in place without forcing it, and still no joy. Bracket #8 lasted 58 hours."


Below is a late model Baron Alternator bracket with very beefy gusseting. Perhaps Plane Power engineers might evaluate that design for a potential solution to their IO470 bracket failures????




Here is an install pirep from Baron B55 owner Joe B.


Put a pair of PP alternators on our Baron this year (2009) and love them. Very clean output and the pair was perfectly balanced out of the factory.