Aircraft Engine Ignition System Progress

[blueldr]

For those members who may also have my negative enthusiam for the magnetos and ignition components we have been forced to use on our aircraft engines for lo these many, many years, there is an interesting article I found in the July issue of "AOPA PILOT" magazine, page 64. I urge you to read it.
Progress may, at last, be coming to GA. Automotive style electronic ignition and associated components are coming!
Hopefully, fuel will be next.

[ghostflyer]

Be very wary of snake oil salesman and their claims . We fitted a laser type ignition system (one system to the r/h mag drive) to a experimental RV with a io-360 engine and it didn't make any difference at all except in hot starting . The clients wallet was lighter also. It wouldn't start when hot . The mag went back on and it would start . The fuel consumption did not change at all over about 50hrs of flying.

[n2582d]

...Progress may, at last, be coming to GA. Automotive style electronic ignition and associated components are coming!
Hopefully, fuel will be next.

Followed by improved flight control systems. Lam Aviation claims remarkable performance improvements. Anyone seen it up close at Oshkosh?

[blueldr]

I'm sorry to hear that one of our members in Australia apparently got screwed on installing a "Laser" ignition system, which I know nothing about. However, if you're even only slightly into the mechanical stuff, surely you can't believe that an ignition system that provides a spark at 25 or so degrees BTC under ALL running conditions can't be improved upon. Can you imagine what a dog an automobile would be with a system like that? From both the performance and fuel economy standpoints, don't you think that your airplane engine would be a smoother and more fuel efficient power plant if the ignition fired much retarded at idle and taxi and fired advanced at higher RPMs while in flight?

[blueldr]

Gary,
I had never heard ofthe "Lam Aileron" before so I Googled it up and watched their short video. Quite unique. It will be interesting to see where it goes. Depending on the difficulty of making the control system, I would expect to see it tried on some home built experimentals, patent permitting.
I would, however, like a little more explanation on how and why they arrived at some of their performance claims.

[rupertjl]

We're working on it, the industry just needs to figure out how to make it cheaper...which is hard to do when you have to go through the Feds for certification. On the experimental side there have been a couple attempts but it hasn't quite been done right (my opinion only) for it to be the barn burner deal that everyone should jump to.

But rest assured you got one guy trying to change that at at least one engine company

-Jud

[n2582d]

... From both the performance and fuel economy standpoints, don't you think that your airplane engine would be a smoother and more fuel efficient power plant if the ignition fired much retarded at idle and taxi and fired advanced at higher RPMs while in flight?

Interestingly, Savier of Lightspeed Engineering writes that his electronic ignition is retarded to around 25* at high power settings and advanced to 42* at low power settings. Personally, if weight and cooling issues could be resolved, I think the ultimate solution is an aero-diesel--no ignition and jet fuel.

[n2582d]

Gary,
I had never heard ofthe "Lam Aileron" before so I Googled it up and watched their short video. Quite unique. It will be interesting to see where it goes. Depending on the difficulty of making the control system, I would expect to see it tried on some home built experimentals, patent permitting.
I would, however, like a little more explanation on how and why they arrived at some of their performance claims.

I'd like to know what he named his home built. The Lam Duck perhaps? Of course with that name it would have to be a canard.

[GAHorn]

Just to put a little reality-check back into perspective.... the typical automotive engine runs it's spark about 5-15 degrees BTDC. This is typicaly near idle, and advances to about 25-30 BTDC at cruise/high-speed. It is usually on a "curve" depending upon various other parameters,....but that is about average for modern auto engines.
Our 65 year old engines run about 26-28 BTDC. This is where they run at high-speed/cruise. LIke auto engines, they "start" at a greatly retarded spark-advance (due to impulse-couplings.) So, in the larger sense, they are not all that different.

HOwever....the auto engine typically has only one sparkplug...hence one source of ignition even at high speed. Their need for advanced spark is due to the flame-propagation and the need to consume all the fuel at the RPMs they typcially operate.

OUr aircraft engines have TWO sparkplugs...and therefore the flame propagation is much more rapid, making up somewhat for the more basic spark advance system. In other words, since aircraft engines operate in MUCH smaller RPM-ranges (in order to efficiently utilize propellers which are RPM-efficiency-limited) than auto engines (which operate largely at 30 mph for most traffic and 70 mph at freeway speeds, but having the advantage of multi-gearing transmissions)...it is not an apples-to-apples comparison.
In short...electronic ignition systems have only minor tweaking ability, and that is a small advantage in steady-RPM useage at limited RPM/Prop-torque loads such as in aircraft. YOu can spend a LOT of money getting a very tiny improvement.

I'd rather have dependability. (Like the good ol' points/condenser systems ...or better yet...the magneto of tractor and dual magnetos of airplane vintage.)


JUst thought I'd needle bluElder a bit....

[rupertjl]

Lycoming's fully integrated electronic control system is able to do a little better than the replacement magneto systems. On the 350 HP engine we've been able to get a significant fuel savings above 75% power, but then again most cruise at 65-75% and the difference becomes much smaller. As George points out, our 65 year old engines do a pretty good job at cruise already, the expense to tweak out a bit more fuel savings is probably negative.

[bagarre]

Considering I just bought two new mags, this makes me feel better

What about the cost savings in spark plugs over the life of the engine?
But, then again TSO'd or "approved" automotive spark plugs will probably cost $25.00 each as well

[GAHorn]

The fine-wire/rare-element plugs will typically last 1,000 hrs or more....but if you don't have a "new" engine, you'll likely not see that. (They are superior for oil burners and lower cyl. positions as well.)
Massive electrodes are "cheaper" ...but they'll typically last only a few hundred hours before the elctrodes are worn out.
Since they should be inspected/cleaned/re-gapped/tossed at regular inspections anyway, the massives are what I usually recommend for low-powered engines such as ours.
(If you're running a high-output fire-breather like one of the "Ram" conversions or a GTSIO engine then you would probably benefit by use of the expensive fine-wires.)