SureFly Electronic Ignition Module

[FW Dave]

I picked up a Left Surefly mag.. I have the L Slick out right now because it let met down.. but havent had time to run the wiring, so I will get it fixed and reinstall it, and get the sure fly done when I do the Longeron inspection and have the belly pans off.. We will be moving the Transponder antenna too, in case we install a Belly pod. Hopefully sometime in march or april

 

[jliltd]

Jim, where is the resistor located? I ordered one

Dave. Sorry for the late reply. I don't get automaic notifications for thread activity.

The reisitors are located under the panel near the ignition switch. There are two, one for R and one for L P-leads. EI calls them "isolators". So you would replace the one on the P-lead for the Surefly with the new resistor. Solder inline like original and cover with heat shrink.

If you hadn't obtained the new rated resistor I would offer to send you one for free.

Jim

 

[jliltd]

Kurt,

You are exactly right that the reason for the fuse is so you can’t reset it in flight. My thought is to place the breaker in the battery area. That way you get to use a breaker and it still satisfies not being able to reset it. Seems like the best way to me.

Joe

There is a reason to have the Surefly fuse or breaker "at" the battery. And that is the only place it should be. The reason is that you are installing a 14 gauge "always hot" wire directly to the battery positive terminal and then running it all the way up to the Surefly ignition module. So if there were a short anywhere along the path between the battery and the fuse/CB the 14 gauge wire would fry and probably catch something on fire in the process. So circuit protection right at the battery mitigates this risk. Nip a short in the bud as it were. Putting the breaker on the instrument panel would unprotect almost the whole length of wire from front to back of the aircraft. Not acceptable. On a related note Surefly STC instructions do not allow supplying power to the unit through a master relay or switch of any kind. It can only be hooked directly to the positive side of battery so its fuse/CB is actually on duty at all times, flying or parked in the hangar.

Jim

 

[FW Dave]

Dave. Sorry for the late reply. I don't get automaic notifications for thread activity.

The reisitors are located under the panel near the ignition switch. There are two, one for R and one for L P-leads. EI calls them "isolators". So you would replace the one on the P-lead for the Surefly with the new resistor. Solder inline like original and cover with heat shrink.

If you hadn't obtained the new rated resistor I would offer to send you one for free.

Jim

Thank you!.. nice

 

[tbienz]

Just installing mine now. As to the question of the remaining mechanical mag “firing into the flame front” and loosing power on takeoff, I don’t have any direct experience with this but I’ve spoken with SureFly and they indicate that the advance timing approval for the Husky is likely going to come in the next few months as he believes that plane is at the FAA right now for the next cycle of approval (the already have many other planes on their AML approved for variable timing). During a high power takeoff (above about 2350 RPM or 24”MP) the electronic mag will go back to base timing (25 deg BTDC on my engine). The variable timing will only become active when the power is pulled back in cruise and at that time, you are normally 70% or less and there is only a slight increase in efficiency by adding a second e-mag over the mechanical/electronic combination. Power loss should not be a problem because it is not active in a high power demand situation anyway. He recommended that I install the MP reference line off the line going to my cockpit instrument so that if the line comes off, my MP gauge will fail and warn me that my ignition system has lost reference. Unfortunately, when the approval comes, you have to take the mag off to reach the switch to turn on the variable timing.

 

[tbienz]

Does anyone know what part of the Husky ignition switch would need to be modified so that the P lead on the new e-mag would NOT be grounded during start. I hope I’m stating that correctly, but just in case: I’m looking to have the right side SIM unit (Sure-Fly “mag”) fire at TDC during start along with my newly overhauled left side mechanical impulse mag. I’ve attached a photo of the back of the ignition switch (‘95 A-1). Do I remove the jumper between the two top left terminals in the photo?

 

[Snowbirdxx]

If you look on the connector side of the ignition starter switch you will see the cables connected and a lug installed. That lug connects two terminals. Remove it and the START position will not ground the lh mag.

 

[tbienz]

Thanks Thomas; is the lug to which you refer seen on the photo of the backside of my switch or are we talking about a different part on the plane? And just to confirm, I’m talking about allowing the RH mag to remain hot during start (so both fire at TDC when I turn switch to the start position).

 

[Snowbirdxx]

The lug is on top of your pic connected to 29. Without this lug the RH mag is hot during the Start position. Do not remove the lug with slick or Bendix mags, unless you use one on the the side with spark retard.

 

[tbienz]

Thanks. The impulse coupled Slick LH mag is still where it used to be, the only change was to put in an electronic mag on the right and the company says I should “leave it hot for start” along with the Slick. So it sounds like removing and capping off wire 29 will accomplish that. Thanks very much.

 

[tbienz]

As an aside (so I understand this better) has anyone come across a wiring diagram for the start switch on our planes. The level of detail I found in the plane’s electrical manual basically just says “start switch.”

 

[Snowbirdxx]

No capping of or removal, just remove the lug. Otherwise the mag is hot all the time. Check Husky Sb # 7 if I recall right. There should be a detailed pic of the lug / jumper

 

[tbienz]

No capping of or removal, just remove the lug. Otherwise the mag is hot all the time. Check Husky Sb # 7 if I recall right. There should be a detailed pic of the lug / jumper

Ok. The SB #7 helped a lot, so its the metal connector I had initially alluded to on wire 28 that has to go. Thanks for your help

 

[Snowbirdxx]

De niente. That's what Husky friends are for!

 

[bcone1381]

I'd like to re-visit the CB or Fuse issue. A fuse is thought of as cheap, old fashion and requiring the need of carrying "extras" on board. But reliability statics favor a fuse over a CB. CB when worn out will pop at a amp rating that is less than rated. A fuse does not wear out. (Fuses that are not accessible in flight don't require the extras be carried)

Something to think about.

Secondly, the aircraft electrical system gurus don't think much about flying after jumpstarting an aircraft due to a bead battery. The battery is your back up electrical system. In fact, when we start leaning towards an electrical dependent aircraft engine, it seems prudent to replace the battery at a regular interval rather then when its worn out, dead and wont turn over the engine any more. Your goal is to have the electrical system of your aircraft such that when the alternator fails, you have a ho-hum event. That means to me download unnecessary items, and have the confidence and instrumentation fly longer than you have fuel in your tanks before your battery dies.

Your Tyco relays help tremendously with that.

 

[Gust Kalatzes]

I'd like to re-visit the CB or Fuse issue. A fuse is thought of as cheap, old fashion and requiring the need of carrying "extras" on board. But reliability statics favor a fuse over a CB. CB when worn out will pop at a amp rating that is less than rated. A fuse does not wear out. (Fuses that are not accessible in flight don't require the extras be carried)

Something to think about.

Secondly, the aircraft electrical system gurus don't think much about flying after jumpstarting an aircraft due to a bead battery. The battery is your back up electrical system. In fact, when we start leaning towards an electrical dependent aircraft engine, it seems prudent to replace the battery at a regular interval rather then when its worn out, dead and wont turn over the engine any more. Your goal is to have the electrical system of your aircraft such that when the alternator fails, you have a ho-hum event. That means to me download unnecessary items, and have the confidence and instrumentation fly longer than you have fuel in your tanks before your battery dies.

Your Tyco relays help tremendously with that.

Is the Tyco Relay PMA’d!

 

[tbienz]

For me it depends a lot on what type of aircraft we are talking about. For the IFR/night travel plane...two 24v 42 amp-hr batteries with q100hr capacitance tests, two generators, two engines & back-up everything.
For the bush plane...not so much. Light is right. It can be hand propped, fly on one mag, start with a lightweight Li-Ion jumper pack in the tool kit. A dead battery in flight is not necessarily an emergency even if you have one e-mag. Assuming daytime/VMC which IMO is how these planes should fly.

 

[chrispo]

Our master switch relay that comes originally on the husky draws about 4 A out of the battery when on. When switching to a surefly n or p I would go for a Bosch relay that draws only 0.2A . That gives you a longer battery life when the generator fails. Longer battery life means now longer dual ignition. Would be interesting to know how much A the surefly is drawing. But with a 10A breaker I am guessing 7 A. But this is a guess only, actual numbers would be helpful. For my kind of flying I would love to know the limits of my systems.

You (indirectly) raise an interesting point, Thomas. One will not see the current draw from the electronic ignition because it's tapped off upstream of the ammeter.

 

[belloypilot]

You (indirectly) raise an interesting point, Thomas. One will not see the current draw from the electronic ignition because it's tapped off upstream of the ammeter.

Their specs say current draw is 0.6A for a 4 cylinder and 1.1A for six.

TECH | SureFly

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