FM200 Controller

[Ted RV8]

For those who are running an FM200 fuel controller on an IO-360-M1 engine a few questions.

Do you feel it?s worth the extra trouble to fit on the engine and the Van?s snorkel, if you running one?
Do you feel there is a performance gain from the 200 controller over the 150, which is told to be a direct bolt up replacement for the Precision Silver Hawk Controller?
Has anyone replaced the Bendix with an FM150 and can confirm any performance gains since the FM150 is supposed to flow more air then the Bendix?

Read DanH write up in kit planes on the Airflow controllers and their better numbers on the flow bench. Did these equate to more horsepower and performance on the air plane?

DanH, a while back you posted a pictured of what looked like a Lycoming M1 sump, was it? Is that picture pretty accurate with regards to the intake tubes to the sump? Was that pictured sourced from Lycoming?

[DanH]

Originally Posted by Ted RV8

Do you feel it’s worth the extra trouble to fit on the engine and the Van’s snorkel, if you running one?

Seat of the pants, I doubt there is much difference between any of the choices. Given the same engine on the same day, a dyno should show a wee bit more for a less restrictive intake. In my mind, the best practical reason to go FM-150 is service down the road.

DanH, a while back you posted a pictured of what looked like a Lycoming M1 sump, was it? Is that picture pretty accurate with regards to the intake tubes to the sump? Was that pictured sourced from Lycoming?

If it was a line drawing, it was probably an illustration from a Lycoming parts manual. The horizontal sump with separate intake plenum is common to many engines, including your M1B and my 390. The intake tubes would be different for parallel valve vs angle valve.

You should be able to download an M1B parts catalog at Lycoming.com

[Ted RV8]

Thanks for the info Dan. Was not able to find the drawing you used in the Lycoming parts downloads. It was from your post looking for an intake tube.
http://www.vansairforce.com/communit...d.php?t=171566

The reason I ask is due to that illustration showing the intake tubes going deep into the plenum area. Wondering if Lycoming was tuning the tubes length for pulse wave. Thinking about to Dave Anders recent article in Kit Planes about pulse wave tuning.

Any idea why the IO-360-M1 intake tubes are 1-3/4? OD at the heads then reduce down to 1-5/8? OD just below the head flange. They stay 1-5/8? OD all the way into the sump.

[DanH]

Originally Posted by Ted RV8

Thanks for the info Dan. Was not able to find the drawing you used in the Lycoming parts downloads. It was from your post looking for an intake tube.
http://www.vansairforce.com/communit...d.php?t=171566

Those are angle valve intake pipes. M1B pipes are not the same, but they do extend into the sump plenum.

The reason I ask is due to that illustration showing the intake tubes going deep into the plenum area. Wondering if Lycoming was tuning the tubes length for pulse wave. Thinking about to Dave Anders recent article in Kit Planes about pulse wave tuning.

That's the idea.

For max power we would prefer to have a pulse of high pressure arrive at the intake port a little after BDC, before the intake valve can close. The piston is already starting on the way up, and the valve is closing, but air is still entering and we want that to continue as long as possible.

Consider this illustration:



You're looking at intake manifold pressure measured in flight through the primer port of my 390's #1 cylinder, i.e. close to the intake valve. The pressure plot you see here is the combined result of all waves, from all sources both positive and negative, as well as the effect of piston motion when the valve is open.

Pressure oscillates in a regular manner. I've marked the time interval with green lines...a peak about every 117 degrees of crank rotation. Counting across from the left, the sixth green line has no pressure peak because the descending piston has not long passed the point of max velocity, and the rapid volume expansion has pulled pressure low. Although it doesn't show on the plot, I'm willing to bet there was a wave arriving at the port, just like the previous five.

Now note the relationship of pressure timing to BDC. At 2400, the unseen pressure pulse is arriving before BDC, too early for ramming in that last bit of air.

I'll be going back to record 2700, when I find time. For now, I'll make a prediction. Timing of the pressure peaks will remain roughly the same, as they are a function of fluid density, pipe length, pipe diameter, and particle velocity. However, more RPM means less time between mechanical events, so BDC will shift left 4 increments on the plot. That will put our #6 phantom roughly 35~40 degrees after BDC, which would very good.

(At 2400 RPM, 720 degrees of crank rotation takes 0.050 seconds. At 2700, it takes 0.0444. Difference is 0.0056. Divide by 0.00133 per increment for this graph, and the answer is a fuzz more than 4 increments.)

Looking at pressure timing is just curiosity on my part, and I cheerfully admit to scrambling for understanding. Right now I've got my beak stuck in a copy of Gordon Blair's Design and Simulation of Four Stroke Engines. The pressure sensor was actually installed for a look at injector nozzle bleed air delta, a story for another thread.

Any idea why the IO-360-M1 intake tubes are 1-3/4? OD at the heads then reduce down to 1-5/8? OD just below the head flange. They stay 1-5/8? OD all the way into the sump.

Nope.

[Ted RV8]

Another good read is Morrison?s book ?Scientific Design of Exhaust & Intake Systems?.
Read it in the 1970?s and was applying it to motorcycle engines with pretty good success.
Read Blair?s book on two strokes in the 1990?s when building two stroke outboards.

Reading Dave?s article stirred my interest again. Kicking around different ideas

The angle valve intake sump and pipes looks like Lycoming applied the wave pulse theories to it. The parallel valve M1 engines not so much. Would be great to talk to the right person at Lycoming to find out more. The reduced diameter intake tube is more expense and more work to manufacture so they must have had a reason.

[DanH]

Originally Posted by Ted RV8

Another good read is Morrison’s book “Scientific Design of Exhaust & Intake Systems”.
Read it in the 1970’s and was applying it to motorcycle engines with pretty good success.

Me too, in the mid 80's. And some of it again last month

Blair's 4-stroke text goes a lot deeper.

The angle valve intake sump and pipes looks like Lycoming applied the wave pulse theories to it. The parallel valve M1 engines not so much. Would be great to talk to the right person at Lycoming to find out more.

I suspect anyone involved with the design is long gone.