LOP - Low and Slow & other stuff...

[David-aviator]

(Last week end it was cruising at 6500' and 7500' for 7.6 hours to and from Spatanburg, SC. The trip burned 60.6 gallons of 100LL for an average of 7.97 gph yielding 150 KTAS. The entire trip going was at 14-43 degrees LOP. #1 injector was changed at the AFP hangar from a .028 to .027 and on the return trip it ran at 28-50 LOP, still have some work getting the cylinders balanced going past peak - the spreads are from cylinder to cylinder across the board)

Today was low and slow - sight seeing locally along the rivers before the next big rain arrives in a couple days. EGT's were leaned to 13-29 LOP, fuel flow set to 6.4 gph and TAS settled down at 132 knots. The engine does run cool at such a power setting, the highest CHT being 305. Last week up higher it was 350, also not bad.

It is becoming habit to twist the mixture knob to see the numbers fall off LOP once power is below 23 inches MP. The EIS 4000 goes into negative numbers once past peak which seems very intuitive and easy to manage. The only down side is fuel flow is not shown on that page and must be tracked down on another page to be reset after LOP. I've looked into getting that info on the LOP page but have not figured out how to do it. Does anyone have fuel flow on the LOP page with this system?

The Lycoming is running smooth, strong and with gusto. Oil was switched from mineral to multi grade 12.6 hours ago and the dip stick is showing 6.8 quarts, down from 7.2 after the change. It was serviced with 7 quarts rather than 8 since that top #8 quart seems to disappear quickly with most Lycomings. I do believe the rings are seated with that mere bit of oil consumption.

There's been much discussion regarding the NG on A models. My experience with it has been in quite a large envelop. With the H6 Subby, the NG weight was 364 pounds. The earlier 2.5 engine weight was slightly less but still up there to where it was difficult to keep the NG off the surface even with full aft stick. Same is true with a Lycoming IO360 angle valve engine and CS prop. It is not a great situation, a lot of dead weigh on that skinny little strut. (Note: there are several guys here who have flipped the beast, I am one of them. It happened with an engine out landing in soft river bottom sand and NG simple dug into it when elevator control was gone, it was up and over ever so slowly.)

The present set up with the parallel valve IO360 and Catto comes in at 244 pounds on the NG. Now that is manageable. The NG can be held off down to taxi speed and there is much less stress on the whole system. The CG comes in at 80.88" aft of datum and the airplane fly's very well, especially on final where it can easily be trimmed up hands off.

I know the trend is toward more and more power and speed, but there is a penalty to pay with the A model. Maybe a tail dragger would be better suited for more power and speed and the up front weight that comes with it. I've flown some high powered beasts in the past and it is a blast, but at this stage of life, I really like the simple, light weight set up.

No matter what, it is joy to fly, especially an RV.

[L.Adamson]

There's been much discussion regarding the NG on A models. My experience with it has been in quite a large envelop. With the H6 Subby, the NG weight was 364 pounds. The earlier 2.5 engine weight was slightly less but still up there to where it was difficult to keep the NG off the surface even with full aft stick. Same is true with a Lycoming IO360 angle valve engine and CS prop. It is not a great situation, a lot of dead weigh on that skinny little strut. (Note: there are several guys here who have flipped the beast, I am one of them. It happened with an engine out landing in soft river bottom sand and NG simple dug into it when elevator control was gone, it was up and over ever so slowly.)

The present set up with the parallel valve IO360 and Catto comes in at 244 pounds on the NG. Now that is manageable. The NG can be held off down to taxi speed and there is much less stress on the whole system. The CG comes in at 80.88" aft of datum and the airplane fly's very well, especially on final where it can easily be trimmed up hands off.

I know the trend is toward more and more power and speed, but there is a penalty to pay with the A model. Maybe a tail dragger would be better suited for more power and speed and the up front weight that comes with it. I've flown some high powered beasts in the past and it is a blast, but at this stage of life, I really like the simple, light weight set up.

One thing that does come into play---- is the pilot, passenger, and baggage weight. Since a good part of this mass is still behind the main wheels, it does offset the nose weight, and takes quite a load off it. If two people stand on my wing steps at the same time, my 6A's tail will hit the ground. It has a rather heavy ( empty) nosewheel weight of 352 lbs. That includes an 0360, Hartzell C/S prop, and the old type "heavy" starter motor.

Yet in flight, the plane is rather agile, even compared to planes 100 lbs or so, lighter. It's surprisingly even competitive on fuel usage compared to lighter weight and smaller engined RV's. That kind of surprises me.

L.Adamson --- RV6A

[pierre smith]

Hi guys,

David beat me to the topic. After reading my Dynon 120 manual, I discovered Lean of peak info and promptly went flying. As I leaned the mixture while running 23" and 2400 RPM, the 120 showed the highest EGT in bold letters and -20, then -35, -46 and so on...denoting degrees lean-of-peak. The other cylinders were less than that, maybe -15, -32 and so on with a couple not lean of peak at all, so I stopped leaning when the hottest egt and LOP was at -47.

How many of you guys run Gami injectors and how much closer to each other are they? My engine in the -10 was built by Aerosport and I haven't discussed this issue with Bart yet.

Blue skies,

[49clipper]

David,
My -6 has the opposite problem on the cg. With the lighter O-320 and the fp sensenich, the cg gets aft real quick. In fact, with myself, wife, and very few pounds, we are within an inch or so of the aft limit. Then, of course, it goes aft more as you burn off fuel. Definitely no problem with a light nose. I sure could use about 30# at the prop.
Jim

[yakdriver]

Originally Posted by pierre smith

Hi guys,

David beat me to the topic. After reading my Dynon 120 manual, I discovered Lean of peak info and promptly went flying. As I leaned the mixture while running 23" and 2400 RPM, the 120 showed the highest EGT in bold letters and -20, then -35, -46 and so on...denoting degrees lean-of-peak. The other cylinders were less than that, maybe -15, -32 and so on with a couple not lean of peak at all, so I stopped leaning when the hottest egt and LOP was at -47.

How many of you guys run Gami injectors and how much closer to each other are they? My engine in the -10 was built by Aerosport and I haven't discussed this issue with Bart yet.

Blue skies,

Pierre, Get a set of tunable injectors from AFP. Install them and run their flight program and you will be able to balance everything out. In cruise my egts are within 5 degrees from high to low and my chts are within 10 highest to lowest. Don

[uk_figs]

49clipper, you could consider a landoll harmonic ring, my -7 tended to aft cg with a 0-360 and FP sensenich and limited the baggage at min fuel. I added the harmonic ring and it is a lot better and I can now carry full bags (100lbs), it does seem to smooth out the engine particularly at the 2350/2400 cruise setting. Adds around 14lbs right at the nose and does not need any cowl mods,
Just a thought.

[49clipper]

Interesting, a friend just offered to let me try his, so think I will try it out.

[49clipper]

14# at 17" aft (flywheel) would change the c.g. from 70.7" to 70.0" even. Nice idea.