Dual surefly installs?
I understand Sure Fly is now approved for dual Sure Fly installs as long as you have a backup battery. Wondering if anyone has done it. My Sure Fly and my bag both have about 1000 hours on them. So I’m thinking that the mag is going to be replaced soon and I’m considering going to the Electronic Ignition system.
Comments
My thinking is that even with a single E-mag, that a backup battery would be a reliable setup. If the E-mag fails or the electrical system fails, the engine is now running on a single mag...not a reliable situation, especially with an older mag.
So, with a dual E-mag, it's more important , besides being required, to have a substantial backup battery of at least 4 amp-hours, larger is better, since each E-mag needs 1.1 amps, to have 2+ hours of battery to power the E-mags.
So, a diode isolation setup is needed, allowing the E-mags to be powered from the main battery or the backup battery, with an alert to indicate that the E-mags were operating on the backup battery, so that the pilot can plan for landing somewhere within an hour or so.
If flying at night or IFR, then the backup need to be able to power some essential avionics as well, adding to the amp-hour capacity of the backup battery. This would require having an 'essential' bus, if the aircraft doesn't already have one.
The STC requires each SureFly SIM to be powered by an independence power source and be hard wired to it. It is not a primary and standby type installation. One SIM can be powered by the aircraft's main battery but the second SIM must be powered by a totally indipendent battery source at all times.
Yes, I understand that.
But in the 'one SIM' setup, if the battery runs down due to an unnoticed alternator failure, the engine is now running on a single magneto.
It would be a more reliable setup to have a backup battery available to power the SIM for at least 1 hour, 2 would be better.
In the 2 SIM setup, I would want to be able to switch the backup battery to either SIM, in case one fails.
my thoughts as an electrical engineer having done a lot of reliability engineering work.
My plan is to have both SIMs powered by both batteries at all times. This could be done with simple diode isolation on each supply wire. SIMs require very little power so a propber second battery should be able to handle two SIMs long enough to fly till fuel tanks are empty.
So, you'll have 2 main sized batteries.?The SIM6 requires 1.5 amps. so 2 of them operating for 5 hours [ or fuel hours], is a 15 AH battery, min. My main RG25XC is 24 AH.
I'd be ok with being able to switch to one of the 2 SIMs on the backup battery, assuming that SIM2 fails, I can switch to SIM1.
My thoughts on a reliable setup.
UPDATE:
I am now pretty certain that I will not be going to a dual Sure Fly set up. My Sure Fly magneto, which was a B Series Has been superceded up to an E model now, Has failed after just 900 hours. It failed a mag check on a cold engine, but worked when the engine was hot then failed all the time. Two cylinders Showed loss of temperature and the aircraft ran roughly when testing the mag. My mechanic contacted Sure Fly. Although the mag has a 2400 hour TBO, it has failed after 900 hours. No partial rebate only a 300 Dollar core charge on a non-rebuildable component.
Step one was to change the plugs no improvement. step two was to change the Ignition harness, no improvement. This series is not able to be rebuilt, so it was returned for a core charge and a new one was ordered.
The new Sure Fly Mag installed and test Flight by the shop is reported to have been successful. I then prepared for a flight and it again failed with two cylinders, number three and four dropping temperatures very abruptly and a very rough running engine. This is with a new mag, new plugs, and a new ignition harness. These are not the same two cylinders that were not functioning with the initial Sure Fly. It appears I have been shipped a brand new malfunctioning mag from Sure Fly. My Mechanic is speaking with Sure Fly and I will be speaking with them tomorrow.
So I have one failed B series, Sure Fly magneto, I have replaced the plugs and the ignition harness and installed an E model magneto from Sure Fly with exactly the same problem. The only difference is that it is affecting two different cylinders this time. I will keep you posted on Sure Fly‘s response. I And hoping they have shipped me a bad magneto because if that is not the problem, I don’t know what else it could be. In the interim, Will be trying it with a standard mag in place of the Sure Fly.
You didn't say what engine that you have, but it runs ok with 2 mags ?
Just curious, did you measure the voltage at the SureFly terminal, [ best with the engine running] , and have a good ground wire. ? I assume that you had a 12v wire directly from the battery to the SureFly.
Yes, the original Sure Fly ran well for 900 hours and then died. It was wired according to manufacturers instructions with the line directly to the battery. When they were doing the work up to evaluate potential causes for the failure, they had me change the plugs, change the wiring harness and then had me bring a separate battery on a cart to the front of the engine to bypass the long wire to the aft portion of the aircraft. When it passed that they then had me bypass the ignition switch by disconnecting the P lead. It was wired correctly, and I followed all of their steps for corrective action. The replacement mag failed immediately. Based on this experience in the amount of time that I spend an actual Instrument conditions, I am returning the new mag in lieu of exchange and going back to a mechanical mag on both sides.
Yes, voltage George correct to the front. The battery is less than a year old. Voltage was confirmed as part of the initial work up.
I was considering using 1 Surefly to replace a mag. Now, I'm not so confident in their system.
BTW, I'm a retired electrical engineer ; designed power circuits for the 'old' computer room line printers.
Is your battery a 24 volt unit, ?
There are a number of reports of misfiring on 24 volt aircraft.
Surefly recommends their 'power conditioner' which reduce the voltage to about 17 volts....a bit strange to me.
Maybe it's an internal regulator overheating.?