Lightspeed Ignition or PMag

[Toobuilder]

You better be really careful with the advanced timing of most EI's with 10-1.

Yep. Thinking the same thing. Big compression, big cam and retarded cam timing all point to high RPM operation. In this case, the move away from EFI and its multitudes of tuning options is a step in the wrong direction, IMHO.

 

[ltampico]

I've had dual Lightspeed on my RV8 for over 11 years, not a single hiccup! Works great

 

[Walt]

Thanks for your heads-up Walt, but could you please eloborate ?

10-1 with advanced timing = detonation, bad juju
I run 9.7 cr fixed timing with good old reliable Bendix mags.
Be cautious on the prop as well, many are not approved for hot rod engines with EI.

 

[Floog]

(2) DC Mini-sensors. 'Bendix' style fuel injection.

 

[Toobuilder]

10-1 with advanced timing = detonation, bad juju

Agree. And in the context of this thread, the Pmag will most certainly be advanced beyond the data plate value at high power settings. So that leaves the Lightspeed as the only reasonable option - assuming that the timing control module is used to retard the timing at high power. This is especially true if the “hot rod” engine discussed is an angle valve head.

 

[Carl Froehlich]

Agree. And in the context of this thread, the Pmag will most certainly be advanced beyond the data plate value at high power settings.

This is reversed. At high power settings the pMag fires close to base timing (assuming that is what you set it up to do). Timing advance comes in as manifold pressure drops. This is the advantage for timing advance - increased engine efficiency at typical cruise conditions.

For the pMag the maximum timing advance is 9 degrees (four cylinder engine, jumper in). In practical application timing never goes that far advanced. My reading on this is 9 degrees is the maximum you ever want to have.

For the six cylunder pMags, you can tailor the timing advance during install. You also have a switch to revert to base timing at any point.

But - for the OPs engine I’d start with base timing around 20 degrees. Collect data and then decide if you want to move it up.

Side note - if memory serves the Lightspeed II+ had a more aggressive timing advance.

Carl

 

[Toobuilder]

At high power settings the pMag fires close to base timing

There are many threads on this site that show the Pmag MP curve comes in early and aggressive. And in this context (High compression, hot rod engine), that’s something to be wary of. It’s my experience that you want an ignition that can “retard” as well as advance for a hot rod (or angle valve) engine. P mag does not have that capability. I “think” the Lightspeed can do that, with the appropriate timing control box.

 

[vlittle]

A bit of history... here are some musings from my extinct 2005 RV-9A website:

Spoiler alert: 20 years after I wrote this *opinion*, I have chosen EMags for my new build. I have no in-flight experience.

" When I heard about EMagair,the maker of P-MAG and E-MAGs, I thought 'what a great idea!'. I designed out my conventional mags and designed in the EMagair products with their assistance.

I placed my order and waited, but the products were delayed several times and I finally had to get my engine built so I cancelled my E/P-Mag order and switched backed to conventional mags. I'll leave all of the wiring in place for a future upgrade, so if EMagair can ever deliver and proved their reliability, I can upgrade. It will cost me more money, but it's a safe way to go.

I have been involved in dozens of new product introductions in my career, and many of them had technical problems and delays at the beginning. The company I have worked for the last 17 years (PMC-Sierra) was very proud of it's record on getting new products out on time with minimal technical problems, but sometimes we had some problem cases.

My opinion is that EMagair is having technical problems, and they want to take the time to get their products right. That's what they should do. In my discussions with them, however, I became concerned about how they are going about things. It's entirely possible that they will have a great product, but a broken business plan. I hope they are getting good business advice.

My background is engineering, marketing and business analysis (mergers and acquisitions). I have seen a lot of companies fail, even though on paper they have a killer product. It's all about the right plan, the right people, execution and documentation.

Documentation?? Yup, 90% of the businesses I analyzed failed because of poor documentation.When you have 50 people designing a 20 million gate integrated circuit, you better get the engineering documents, manufacturing and customer documents right or you will never, ever find all of the bugs, never ship the product for revenue and never have a successful business.

EMagair is a different animal, I agree... but being successful with a product like this (eventually to be certified) will swamp them in paperwork. For example, what is their qualification test plan?

Are they going to let their customers debug their products for them? I hope not. If I were them, I'd get 3 or 4 aircraft test beds in the air as soon as possible with backup magnetos, and run them through a battery of tests, collect data and analyze it before I shipped any products to customers.

Things to think about...

- will they work at temperature extremes?
- will they work with a lot of temperature cycling?
- what about high altitudes?
- what about vibration (normal and abnormal)?
- what about contamination from engine fluids or dirt?
- what about reliability in corrosive atmospheres?
- what about susceptibility to electrical interference (comm radios, transponders, etc.)?
- what happens when the internal micro goes insane?
.... and so on.

There are many questions.They have been good at answering some, but not others. Food for thought. Good luck to them. If they are successful I will upgrade."

I think they passed the corporate longevity test! In my Harmon Rocket, I used one impulse mag and an Electroair. The Electroair had problems due to the timing ring installation (caused by the engine builder). First engine run in my new build with EMags is coming up soon...

 

[Walt]

Agree. And in the context of this thread, the Pmag will most certainly be advanced beyond the data plate value at high power settings. So that leaves the Lightspeed as the only reasonable option - assuming that the timing control module is used to retard the timing at high power. This is especially true if the “hot rod” engine discussed is an angle valve head.

The SDS CPI ignition is what I would use if installing an EI with my engine (370/ 9.6 CR)
Fully programmable.

 

[rswalden]

....."Here is my stance on anything electronic, learned from a lifetime in technology, as well as aircraft. I never use the same system as a backup in a critical application. As an example, I've never had a failure of my Advanced Flight Systems EFISs in flight, yet I have them backed up with a Garmin G5 and an Avidyne 550.

I also consider the ignition system a pretty critical system. I like the advantages of EI, and always use one, backed up by a magneto. I'd be OK with a second EI by a different manufacturer as well.

Vic's is sage advice from a pro. True redundancy isn't so obvious.

I have a LightSpeed ignition and one Bendix mag. Love the LightSpeed: it optimizes the spark and I've been very happy with it.
My electrical system previously used the belt-driven Plane Power 60a alternator and a Plane Power 30a engine mounted backup alternator.
And my Dynon avionics consisted of DUAL SkyView displays and DUAL ADAHRS units. Perfect redundancy for IMC, right?

Well, not so much.
Last year I experienced total electrical failure while IMC on a cross country. The internal regulator on the Plane Power alternator failed, and the engine mounted backup couldn't handle the sudden load and sheared the internal shaft. I watched the battery voltage die a slow death during my divert to a VMC towered airport. 15 miles out, the battery DC buss dropped off line. My Lightspeed ignition died. No lights, no flaps, no transponder, no radio. Fortunately I gave approach control a heads up on my pending electrical failure. Received a green light from tower for the uneventful landing.

The self-powered E-mag/P-mag alternators weren't around 20 years ago when I built my airplane, but I would go with one of those today in place of my LightSpeed. I replaced my Plane Power alternators with B&C's and have been VERY pleased with them.

Regarding my "redundant" Dynon system--it isn't as trustworthy as I thought. I've had several complete EFIS failures in flight without warning and am convinced that dual EFIS units by the same vendor with the same faulty firmware isn't a good idea after all. For IMC flights now, I slap a self-powered GPS attitude indicator on my panel using a velcro mount. When it all comes down to it and everything fails, that little life-saver REALLY gives me what I need to stay alive in IMC. Of course, something like a Garmin G5 (different vendor) would do the trick as well.

 

[Kyle Boatright]

Vic's is sage advice from a pro. True redundancy isn't so obvious...
... Of course, something like a Garmin G5 (different vendor) would do the trick as well.

None of this stuff is perfect. I emailed my vendor of choice today asking for suggestions as to why my G5 (with battery back-up) routinely shuts down in flight.

 

[dmattmul]

None of this stuff is perfect. I emailed my vendor of choice today asking for suggestions as to why my G5 (with battery back-up) routinely shuts down in flight.

Garmin Service Alert: G5 Battery Discharge - Aviation Consumer

Emergency battery power for primary EFIS is the belt-and-suspender backup for total electrical system failure, but not for some Garmin G5 models that sit for long periods

www.aviationconsumer.com

Please post your resolution, our vendor of choice resolved similar issue perfectly. (Mine never shut down in flight but could see battery was not charging past 75%)

 

[RV10inOz]

Thanks for your heads-up Walt, but could you please eloborate ?

I would be starting at about 18 degrees. And yes I know what I am talking about. And I would use NOTHING but SDS or slicks. And the slicks would be set at 20.