SUREFLY DUAL SIM - Electronic Ignition

[wcb]

I recently went with the dual Surefly Electronic Ignition on my Ovation with the 310 upgrade!

 

1. Has anyone else done this upgrade?  As well as more specifically has anyone done it with the IO550? If so how long and what kind of numbers are you seeing best LOP and ROP operations.

2.  A couple quick observations for those considering it.

a.  LOP operations are much deeper and smoother.  LOP can run roughly 100 LOP smoothly (ALL THE WAY DOWN TO 11GPH)(and temps are solid (hottest CHT around EDIT (It is 350 CHT at 9.5k and 25 rpm and 20 mp) {prior was around 335 CHT at 35 LOP)

b.  Temp increases in all phases of flight (take off and in both ROP an LOP operations).  (Most notable I am not liking what I am seeing in take off as I hitting on my hottest CHT 400 and in ROP operations (100 ROP) my hottest CHT around 380 (prior was around 350).

c. Starts quick every time.  YES, even hot start!

My first thoughts (after only a few flights) if you fly nothing but LOP they are AWESOME!  As I continue to fly and hopefully work out any issues on the ROP side I will update the group.  I own a Mooney to go fast so I do like to fly ROP about 50% of the time.

 

A couple of additions to answer some questions below:
YES to harness (NEW MAGGIE).  Inspected plugs and were near perfect so we did not change.

YES and use GAMI injectors

Fuel Flow is about 26 on departure. 

 

 

Edited May 18 by wcb

[alextstone]

Questions:  did you also change plugs and wiring harnesses and if so, how long has the old ones been in service?

[Pinecone]

For the ROP and takeoff/climb, have you had your fuel system set up by someone who knows how to do this?  Continentals are a bit involved.

[Ragsf15e]

18 hours ago, wcb said:

I recently went with the dual Surefly Electronic Ignition on my Ovation with the 310 upgrade!

 

1. Has anyone else done this upgrade?  As well as more specifically has anyone done it with the IO550? If so how long and what kind of numbers are you seeing best LOP and ROP operations.

2.  A couple quick observations for those considering it.

a.  LOP operations are much deeper and smoother.  LOP can run roughly 100 LOP smoothly (and temps are solid (hottest CHT around 335 {prior was around 325 at 35 LOP)

b.  Temp increases in all phases of flight (take off and in both ROP an LOP operations).  (Most notable I am not liking what I am seeing in take off as I hitting on my hottest CHT 400 and in ROP operations (100 ROP) my hottest CHT around 380 (prior was around 350).

c. Starts quick every time.  YES, even hot start!

My first thoughts (after only a few flights) if you fly nothing but LOP they are AWESOME!  As I continue to fly and hopefully work out any issues on the ROP side I will update the group.  I own a Mooney to go fast so I do like to fly ROP about 50% of the time.

Are you sure you’re getting enough fuel flow on takeoff?  Here’s the real point, at very high power, the SF doesn’t provide any advance.  So it’s unlikely that it’s causing your higher temps unless something else isn’t set up right.  Now they use to publish an advance map, that showed advanced timing kicking in around 5,000’, so, roughly around 75% power and then slowly increasing as power is reduced by thinner air at altitude.  It’s unlikely that the SF is causing higher temps in the climb unless the initial timing on them isn’t set right or something else isn’t (like fuel flow).  I only have one SF, and a smaller engine, so this isn’t a good comparison, but it’s hard to see any difference in temps unless I compare ROP cruise data at ~10,000’, and then it’s only like 10 degrees warmer.

[McMooney]

I"m most likely adding the seond sim at annual this year,  I've had absolutely 0 issues with the first.

[philiplane]

there is zero benefit to a dual Surefly installation, and significant downside. If you have a SIM failure, there are no spares anywhere you might land. You'd have to put a magneto back on it, or wait days to get a replacement. This has already happened in the Cirrus world.

Second, there have been a few failures, not many, but it is an electronic device, and we don't yet know how long it will last. Especially with the extra heat of a Continental, where it sits on top of the engine and gets baked on every shut down. Lycoming installations don't suffer from this.

I've had Sureflys on my twin since they were first approved. They work great. But there is no way I would put two on each engine, until the fleet accumulates enough hours, and years, to prove that they will last.

[Shadrach]

10 minutes ago, philiplane said:

there is zero benefit to a dual Surefly installation

So you are of the opinion that having a dual, optimally timed ignition event on each cylinder has no benefit over a single optimally timed and a single fixed ignition event? 

It seems to me if there is no benefit to having two, the benefits of having one must be marginal.  I am speaking from a cruise performance standpoint, putting ease of starting and extended maintenance intervals aside.

[philiplane]

9 hours ago, Shadrach said:

So you are of the opinion that having a dual, optimally timed ignition event on each cylinder has no benefit over a single optimally timed and a single fixed ignition event? 

It seems to me if there is no benefit to having two, the benefits of having one must be marginal.  I am speaking from a cruise performance standpoint, putting ease of starting and extended maintenance intervals aside.

I don't have an opinion on this, I follow the facts from 20 years of experience in dual-fuel customized engine controls, NASA studies of aircraft engines for emissions/performance, electronic ignition conversions, and more. People don't fully understand combustion events. Once you light the fire, it burns. Adding a second source is for redundancy, not for improving the performance of the initial ignition. There's a lot of nonsense that claims that higher voltages, or longer dwell times, make more power. That is untrue. If there is spark at the right time, the mixture burns. More spark does not make it burn better, more spark just wears out your plugs faster.

I've written about this extensively. If you have an optimized ignition source like a Surefly, not a crude one like the Electroair, adding a second one only provides a backup. The initial ignition event is what matters. You get better starting because you have full voltage the moment the engine cranks. No waiting for an impulse coupling or showr of sparks to build voltage. You get better low-power performance due to the advance available under those conditions. You get zero benefits in a full power takeoff and climb because certification prevents advancing timing when detonation margins are small.  

So the benefits of the first SIM installation are HUGE, and the second one is virtually nil. 

[N201MKTurbo]

4 hours ago, philiplane said:

I don't have an opinion on this, I follow the facts from 20 years of experience in dual-fuel customized engine controls, NASA studies of aircraft engines for emissions/performance, electronic ignition conversions, and more. People don't fully understand combustion events. Once you light the fire, it burns. Adding a second source is for redundancy, not for improving the performance of the initial ignition. There's a lot of nonsense that claims that higher voltages, or longer dwell times, make more power. That is untrue. If there is spark at the right time, the mixture burns. More spark does not make it burn better, more spark just wears out your plugs faster.

I've written about this extensively. If you have an optimized ignition source like a Surefly, not a crude one like the Electroair, adding a second one only provides a backup. The initial ignition event is what matters. You get better starting because you have full voltage the moment the engine cranks. No waiting for an impulse coupling or showr of sparks to build voltage. You get better low-power performance due to the advance available under those conditions. You get zero benefits in a full power takeoff and climb because certification prevents advancing timing when detonation margins are small.  

So the benefits of the first SIM installation are HUGE, and the second one is virtually nil. 

With two plugs, you are lighting two fires from two sides of the cylinder. So aside from redundancy, it does shorten the time it takes to burn the whole charge. This shortens the time from ignition to peak cylinder pressure. To get peak cylinder pressure at the same crank angle with just one plug, would require advancing the spark. That’s why the RPM drops when doing a mag check.

So, you can get the same performance with a single plug, with a few degrees more advance.

[Shadrach]

 

11 hours ago, philiplane said:

I don't have an opinion on this, I follow the facts from 20 years of experience in dual-fuel customized engine controls, NASA studies of aircraft engines for emissions/performance, electronic ignition conversions, and more. People don't fully understand combustion events. Once you light the fire, it burns. Adding a second source is for redundancy, not for improving the performance of the initial ignition. There's a lot of nonsense that claims that higher voltages, or longer dwell times, make more power. That is untrue. If there is spark at the right time, the mixture burns. More spark does not make it burn better, more spark just wears out your plugs faster.

I've written about this extensively. If you have an optimized ignition source like a Surefly, not a crude one like the Electroair, adding a second one only provides a backup. The initial ignition event is what matters. You get better starting because you have full voltage the moment the engine cranks. No waiting for an impulse coupling or showr of sparks to build voltage. You get better low-power performance due to the advance available under those conditions. You get zero benefits in a full power takeoff and climb because certification prevents advancing timing when detonation margins are small.  

So the benefits of the first SIM installation are HUGE, and the second one is virtually nil. 

 

@N201MKTurbo touches on some of what I was getting at. I know that Surefly states the unit is capable of delivering up to 38° of advance, but I’ve not seen the timing maps.  There are certainly advantages to having dual ignition. The large bore of most aero engines obviously benefits from two points of ignition propagation. I have had to climb on a single mag and the degradation in performance is noticeable, whether it’s significant is in the eye of the beholder. Single point of ignition is better than none…

To Rich’s point, you can advance timing further on a single point of ignition to match the same optimal pressure point of a dual advanced ignition system, but then you have pressure building further before TDC, which means less energy delivered at the optimum crank angle and more energy delivered during the compression stroke.  Not ideal for efficiency.
All of his may seem like angels dancing on the head of a pin in the real world.  I have no dog in the fight, but I have not seen any data on the real world performance increases with the single variable timing mag. Seat of the pants reports vary from ho hum to I think I’m getting a few fractions of a gallon per hour in fuel savings all other things being equal.
I (apparently incorrectly) attributed the lack of significant performance increase to the possibility that the effects of the advanced ignition event were not being fully realized because of the single point of propagation across such a large combustion chamber (relatively speaking). This was reinforced by my reading Nigel Speedy’s article on ignition advance, as he seems to see significant performance gains running dual advance over stock fixed mags.  Gains that far exceed any claims I’ve seen of those running a single point of advance. 

Given my lack of understanding of combustion science and my lack of solid performance data on the Surefly installation, perhaps you might expand a bit on the performance gains that you’ve seen.

 

[N201MKTurbo]

I have a book from 1938 that goes way deep into the combustion event and cylinder pressure vs crank angle. You need a PHD in math to totally get all the calculus. I know enough to be dangerous. It goes into flame speed with regard to mixture, pressure, temperature and fuel composition and RPM.
 

After all that math, a rule of thumb is, you want maximum cylinder pressure at about 15 degrees after TDC, so you have to work backwards from there to get the optimum spark advance. 

Of course, you can skip all the math and put the engine on a dyno and adjust the advance for maximum torque. 
 

But you have to consider detonation. Maximum torque happens at maximum cylinder pressure at the optimum crank angle. But at some combination of fuel, pressure and temperature, the charge will detonate. Which means the remaining unreacted fuel charge will instantly and completely react. This will cause a supersonic shock wave inside your cylinder. The intensity of that shock wave depends on how much unburned fuel is left in the cylinder when the pressure and temperature get to the detonation conditions. It usually happens near the end of the burn, so it is usually much h smaller than it could be.

Anyway, at high manifold pressures and high cylinder pressures, you may get to detonation before you get to maximum torque, so you have to operate at sub optimal max pressures crank angles.

The higher the octane number of the fuel, the higher the power that can be achieved with optimized combustion events.

A richer mixture burns faster than a lean mixture. Therefore the advance necessary for getting max pressure at the optimum crank angle is less, and conversely, a lean mixture requires more advance to get max pressure at the optimum crank angle.

The optimum crank angle is complex. It is the highest mean crank torque which is a function of the rate of expansion of the fuel air charge, the rate of expansion of the cylinder as the piston goes down and leverage of the piston on the crankshaft. The cylinder volume and leverage on the crank is the sum of two sine functions. One is the crank angle and the other is the connecting rod angle to the piston. It makes nuclear physics look simple.

[philiplane]

17 hours ago, N201MKTurbo said:

With two plugs, you are lighting two fires from two sides of the cylinder. So aside from redundancy, it does shorten the time it takes to burn the whole charge. This shortens the time from ignition to peak cylinder pressure. To get peak cylinder pressure at the same crank angle with just one plug, would require advancing the spark. That’s why the RPM drops when doing a mag check.

So, you can get the same performance with a single plug, with a few degrees more advance.

It's hard for our brains to comprehend the microscopic difference the second spark makes at cruise power. We're talking milliseconds of burn time. You can't extrapolate the 100 rpm difference you see in a pre-flight mag check, to what happens during cruise. The hazard of having two opposing flame fronts also increases the octane requirements to avoid detonation.

[jetdriven]

22 hours ago, philiplane said:

I don't have an opinion on this, I follow the facts from 20 years of experience in dual-fuel customized engine controls, NASA studies of aircraft engines for emissions/performance, electronic ignition conversions, and more. People don't fully understand combustion events. Once you light the fire, it burns. Adding a second source is for redundancy, not for improving the performance of the initial ignition. There's a lot of nonsense that claims that higher voltages, or longer dwell times, make more power. That is untrue. If there is spark at the right time, the mixture burns. More spark does not make it burn better, more spark just wears out your plugs faster.

I've written about this extensively. If you have an optimized ignition source like a Surefly, not a crude one like the Electroair, adding a second one only provides a backup. The initial ignition event is what matters. You get better starting because you have full voltage the moment the engine cranks. No waiting for an impulse coupling or showr of sparks to build voltage. You get better low-power performance due to the advance available under those conditions. You get zero benefits in a full power takeoff and climb because certification prevents advancing timing when detonation margins are small.  

So the benefits of the first SIM installation are HUGE, and the second one is virtually nil. 

I wonder what makes you think that the electroair is crude? I’ve installed plenty of both and I have an electro air on my plane, even though I think the performance is about the same, the electroair  has a quite a bit larger coil and more  voltage than the surefly.  That said, I wouldn’t install two of any of these electronic devices. Once is lit, it’s lit. 

[N201MKTurbo]

22 minutes ago, philiplane said:

It's hard for our brains to comprehend the microscopic difference the second spark makes at cruise power. We're talking milliseconds of burn time. You can't extrapolate the 100 rpm difference you see in a pre-flight mag check, to what happens during cruise. The hazard of having two opposing flame fronts also increases the octane requirements to avoid detonation.

Most of the things people do to increase the power of their engines have very little effect.

[M20F]

9 hours ago, N201MKTurbo said:

Most of the things people do to increase the power of their engines have very little effect.

As a proud owner of a super charged 1971 MGB I have the receipts to prove your theory fact.  

[LANCECASPER]

On 5/17/2024 at 12:38 PM, philiplane said:

there is zero benefit to a dual Surefly installation, and significant downside. If you have a SIM failure, there are no spares anywhere you might land. You'd have to put a magneto back on it, or wait days to get a replacement. This has already happened in the Cirrus world.

Second, there have been a few failures, not many, but it is an electronic device, and we don't yet know how long it will last. Especially with the extra heat of a Continental, where it sits on top of the engine and gets baked on every shut down. Lycoming installations don't suffer from this.

I've had Sureflys on my twin since they were first approved. They work great. But there is no way I would put two on each engine, until the fleet accumulates enough hours, and years, to prove that they will last.

This one lasted 200 hours on the back of a Lycoming engine, where heat shouldn’t have caused the failure:

https://mooneyspace.com/forum/13-mooney-bravo-owners/

[Pinecone]

12 hours ago, philiplane said:

It's hard for our brains to comprehend the microscopic difference the second spark makes at cruise power. We're talking milliseconds of burn time. You can't extrapolate the 100 rpm difference you see in a pre-flight mag check, to what happens during cruise. The hazard of having two opposing flame fronts also increases the octane requirements to avoid detonation.

Hmm, ever done a cruise power mag check??????

Go to do one and then tell use it makes a microscopic difference.

[Pinecone]

12 hours ago, N201MKTurbo said:

Most of the things people do to increase the power of their engines have very little effect.

For certificated aircraft, yes.  For your typical import tuner type, yes.  In other circles, not really.

IIRC, Firewall Forward used to build parallel valve IO-360s to near 210 HP for the aerobatic guys.  I installed a Stage 4 engine kit on a BMW M Roadster, that added about 60 HP.

[N201MKTurbo]

2 minutes ago, Pinecone said:

For certificated aircraft, yes.  For your typical import tuner type, yes.  In other circles, not really.

IIRC, Firewall Forward used to build parallel valve IO-360s to near 210 HP for the aerobatic guys.  I installed a Stage 4 engine kit on a BMW M Roadster, that added about 60 HP.

Yes, I was talking about certified aircraft engines. Most don’t realize how optimized they already are. 
 

But even thinking about hot rodding auto engines. When you increase the power output beyond its structural design, you compromise reliability.

With aircraft engines, I value reliability above performance.

[Shadrach]

6 minutes ago, Pinecone said:

For certificated aircraft, yes.  For your typical import tuner type, yes.  In other circles, not really.

IIRC, Firewall Forward used to build parallel valve IO-360s to near 210 HP for the aerobatic guys.  I installed a Stage 4 engine kit on a BMW M Roadster, that added about 60 HP.

I know of at least one experimental IO360 pushing 250hp. High compression pistons, ported heads, dual ignition advance, tuned exhaust.

[Pinecone]

Basically agree.

You can get some more performance with good reliability on some engines.

[N201MKTurbo]

8 minutes ago, Shadrach said:

I know of at least one experimental IO360 pushing 250hp. High compression pistons, ported heads, dual ignition advance, tuned exhaust.

So, why didn’t they just install an IO470?

[Shadrach]

16 minutes ago, N201MKTurbo said:

So, why didn’t they just install an IO470?

I suppose they wanted to avoid the extra 100lbs on the nose, and enjoyed the superior fuel specifics of the high compression (11:1 IIRC) ported a polished Lycoming. 
or maybe they just wanted to soup up a Lycoming for the sake of doing it. I’m sure you’ve met the type.

[Jerry 5TJ]

35 minutes ago, N201MKTurbo said:

With aircraft engines, I value reliability above performance.

Ditto. 

[Shadrach]

30 minutes ago, Pinecone said:

Basically agree.

You can get some more performance with good reliability on some engines.

Indeed. My diesel sedan is in the shop getting a tune right now should have to back Tuesday.  When I dropped it off it had 413lb ft of torque flat bereeen 1500 and 3000rpm and 255hp. 
When I pick it up it will have 545lb ft across the same range and 335hp. Better fuel economy as well if I can keep my foot out of it.