V

Vyking

Member
Before building my RV, I had spent a career flying fighters and not GA aircraft. I found that aircraft fell into one of two categories, fighters or targets and I was lucky to fly the former. But, when the government stopped buying my fuel, I realized there were some aircraft that were technically targets but had handling qualities somewhat close to a fighter?s. Thus, the RV.

When I built it, I added a lot of technology supported by a robust and redundant electrical system. I had protections against trim or flap inputs from creating short circuits, ways to isolate malfunctions, lights to warn of problems, and backup electrical power sources. I was very satisfied but was still on the lookout for better ways to do things and not afraid to try new ideas. So last March, I retrofitted a Vertical Power VP-200 power management system in my 300-hour RV and became a beta tester of the system. Since then, I have over 60 hours with the system and report the following:
- It certainly would have been easier to install during construction; a retrofit is tedious . . . but doable.
- The net weight gain was about +1 pound: 5# out (fuses, busses, wire, circuit breakers, switches, and relays) and 6# in.
- Initial configuration and subsequent changes have been very easy thanks to a menu-driven interface.
- The core features are very stable; i.e., the ability to manually and automatically control electrical devices, detect faults, and switch modes based on engine and GPS data. Modes are phases of flight; e.g., start, taxi, takeoff, cruise and landing. The user configures the VP-200 to power electrical systems up or down when the system switches among modes, either automatically based on GPS and engine data or manually by pushing a soft key on the system's display unit. Examples are turning on avionics after start and turning on the boost pump and landing lights when in landing mode and turning them off in taxi mode.
- Though only tested and not actually needed, the system's automated responses to emergencies; e.g., engine failure or fire and backbone electrical system failures, is impressive.
- The system has worked very well and with each software upgrade, performance and capability has improved. That said, the system still displays six cylinders for my four-cylinder engine.
- The ability to download software and update the system via a USB stick is a benefit compared to some avionics systems requiring laptops to update software or, worse, returning hardware to the factory for updates.
- The voice alerts and advisories are a real plus and should get even better over time; e.g., aurally telling me when the autopilot autonomously disengages. Yes, it happens.
- The company has been very responsive to suggestions and has fixed problems very quickly.

John Nystrom
Placitas, NM
RV-7A, N7VD
 
John:
Cool. I had no idea the units were in the field before August. The one question I have is there any situation you can think of when the unit might sense a mode of flight other than the one you're in?
 
Mode switching reply

I can't answer with one word so I need to elaborate a bit. The system is logic driven and does well in determining what I?m doing. But, it can?t anticipate all my actions.

Consider the transition from taxi to takeoff modes. The system doesn?t know whether I?m taxiing to the runway or onto the runway. Until I increase power a lot and the knots begin to climb, the system stays in taxi mode. Once it senses high rpm and some knots, it switches to takeoff mode and turns on boost and landing lights. But, that happens after I?ve rolled a bit. Is the mode wrong as I begin the roll? No by logic but yes by intention. So, rather than wait and have boost and lights come on during takeoff roll, I push the takeoff mode as I take the runway. Another example is the transition from cruise to landing modes. If I fly a sedate (bomber/school house) pattern, the system automatically switches to landing mode and the boost and lights come on early. Great! But if I arrive fast for an overhead pattern, the system will transition later than I would like so I jump to landing mode manually to get boost and lights earlier. Also great!

John Nystrom
 
VP 200 Override

Hi John,

I am also very interested in acquiring a VP 200 for my RV8a project (well... to be honest, I have almost decided to do so. One of the reasons is Marc?s phantastic responsiveness and preparedness to deal with dumb questions). Here is one for you: Did you provide for some form of VP 200 override?

What happens if the VP 200 fails all together. Are you still able to fly your bird?

I am thinking of designing my engine wiring around an override bus architecture. In case of a VP 200 failure the override bus will be activated to:

* keep the engine running (problem: Eggenfellner Subie, electronic ignition, no magnetos,)
* re-start the engine if necessary
* possibly operates flaps and trim (Marc?s philosophy here is to leave everything as is in case of a failure. Don?t know yet if I completely agree)

Note: Experimentals in Europe are all day-VFR so no instruments need to be powered via the emergency. No need for instrument and lighting wiring if in override mode. I shall be able to fly the plane with backup steam gauges to the nearest airport.

Any thoughts?


Thanks
 
Answers

For Bob Collins:

The control unit hangs vertically off the left forward half of left rib running between the panel and firewall. Though the location is forward and up, I made a rack that makes installation and removal fairly painless. Re effort, every installation, whether it be during or after construction, will be different. Some may have the panel space and others may need to reorganize the panel. In my case, I had to make a replacement panel that was taller than stock so could not use Van?s. I elected to move a CDI from the left of the centerline to the right so had to extend the cable to the CDI by 14 inches. That?s 14 inches times 23 individual wires. The actual installation of the system?s components was easy.

For Bob Collins and Michael Mueller:

If the VP-200 were to fail completely, the states of all devices will freeze. That?s likely better than having all devices turn off. As a fallback, the system has two 5A failsafe/override/backup circuits. I originally wired boost and EFIS but found early on that the 5A circuit boost circuit would fault even though I had previously flow 300 hours with the same 5A fuse in the boost circuit. So, the boost went to a 10A pin and now I have only the EFIS on a backup circuit. As a hedge against system failure, built an auxiliary electrical panel that has two separate buses, a 6-fuse and 10-fuse bus. The small bus is always hot and supplies power to some small area lights, two aux power receptacles, the EFIS backup circuit, independent boost switch, and 10-fuze bus. The SPDT boost switch gets power from the VP or the battery depending on switch position and sends it out the center tab to the pump. The power to the 10-fuse bus runs through a DPDT switch with one pole powering the bus and the other going to ground and the battery contactor. The 10-fuse bus powers pitch trim, autopilot, audio panel, a GPS/NAV/COM (needs two fuses), transponder, LASAR ignition, voltage regulator, engine information system, and starter. My original design had power wires to the 10 circuits joining power wires coming from the VP-200 with both power sources isolated from each other by diodes, the way VP wires their two 5A backup circuits. But, it was easier by far to put two connectors on the back of the aux panel, one with VP-200 power and one with aux power. A cable with wires running to devices connects to one or the other of the connectors. To switch power sources, I need to move the cable. Except in testing, I have never had to do that. If you have the bandwidth, I can email a 42-page journal that documents the retrofit. It is a 6.6 GB pdf file.

John Nystrom
 
John came up with a pretty innovative way to wire in backup circuits. Since then, though, we've come up with yet another option to wire backup circuits. You can find details in the installation manual, and in a document entitled "Backup Wiring" found here: http://www.verticalpower.com/documents.html

The system design allows you to choose how much "backup" you want. John's backups, for example, allows him to start the engine and fly home VFR/IFR with most, if not all, avionics working if the system fails (just as backup gauges allow you fly safely if your EFIS fails). I only have a backup for the EFIS and ADAHRS power to provide attitude information if in in IMC conditions if the VP-200 should fail. I also have a second backup EFIS with a battery, and a hand held radio and GPS. So, as you can see, two different approaches.

It's up to you to decide which approach (or something in between) works for you. :)
 
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