My SR22 is fully electric, as are almost all SR20s and SR22s (only the very first one had a vaccum pump). The latest model don’t even have mechanical backup instruments but small screens.
My microlight is fully electric, too, in a sense… but not as meant originally, of course.
Interesting news from Oshkosh – BendixKing introduces KI-300 Retrofit electronic attitude gyro to replace e.g. KI-256 :
Astonishing…
Not because this is rocket science, or because it has not been a totally blindingly obvious business opportunity for many years to certify an electric KI256…
Still, great news for many people.
Castleberry have been making an electric KI256 for about 10 years but it never got an STC for the King autopilots. It also doesn’t quite work to replace the KI256 because King changed the excitation frequency in the autopilots from the value in the KI256 test spec…
The pricing is a bit steep!
But I bet that the STC will not allow you to do the obvious thing which is to install this RHS and have it switchable so your King AP can be pitch/roll driven either from the Aspex EFD1000+EA100 / G500+GAD43 OR from this unit. That way you would retain your autopilot when the LHS stuff packs up, which it surely will one day, and when it does you are looking at a loss of a huge amount of functionality and a loss of your autopilot.
Peter
A friend of mine did it, he is on the G reg. I guess that the rules are differant.
Ben
Peter wrote:
It also doesn’t quite work to replace the KI256 because King changed the excitation frequency in the autopilots from the value in the KI256 test spec…
I fail to see how this should be any problem for a fully electronic device.
Kings own circuits use about 1 transistor, 2 resistors and 1 capacitor to chop the signal to the excitation frequency…
A friend of mine did it, he is on the G reg. I guess that the rules are differant.
Ben – What did he exactly do? I mean, what equipment did he install?
I fail to see how this should be any problem for a fully electronic device.
All I recall is that somebody in the USA tried it and found that the different frequency produces a much higher output from the pitch/roll pickoff coils, so the control loop became unstable. I suspect nobody else ever tried it or tested it.
If Honeywell STCd their electronic AI product for their autopilots then they presumably taken care of this. Anyway, they won’t be using pickoff coils; if they have done what everybody else has done, they generate an internal serial stream with the ARINC429 pitch/roll data and then they implement an LVDT emulation, with some op-amps. They probably lifted the pitch/roll gyro design from the now-dead KFD840 PFD.
Why would one buy that instead of an Aspen? The pricing seems insane.
The price just hands business to Aspen on a plate.
But not everyone wants to re-hack their panel.
Especially in larger aircraft or commercial / military. These lowish cost GA products are used almost totally only in the low end GA market.
5 grand for a glorified solid state AHRS. Please tell me i’m dreaming.
The key is in the STCd KI256 emulation, for autopilot pitch/roll reference.
A KI256 is c. 10k depending on version.
