Idle in the pattern - gear box wear?

[Tacco]

When I?m solo, I rarely use any additional power after reducing the power to idle, abeam the numbers, 1000 AGL, no wind, and flying a traditional pattern. My static idle (on the ground) is set at about 1550. The engine will idle at about 2000 on approach, decreasing below that after or near touch down. My approach speed is 60 until final, then 55 until over the numbers. Question: is windmilling the prop on approach like this harmful to the gear box.

[Piper J3]

That is correct operation. 1500ish on the ground is good to allow prop drag on final. Prop drag is trying to back-drive the engine so gear mesh is a constant loading all in one direction of rotation. In other words - no chatter of the gears.

[RFSchaller]

Mine idles about 1750 on the ground and presents no issues with floating in the flare.

[magiccarpet]

Originally Posted by RFSchaller

Mine idles about 1750 on the ground and presents no issues with floating in the flare.

Same here 1750 on ground. Seems to be right.

[NinerBikes]

We have obstacles on both ends of the runway, in the form of tall trees, electrical power lines, and buildings, that are quite close to the runway.

The owner has his RV-12 with 2 people in it set up for 1550 rpm, on the ground. Still requires a lot of forward slip to clear the obstacles, make the fence, and attempt to drop on the numbers. He uses a 65 kt approach with both of us in the plane, and 58 or 59 kts solo.

Says the plane still wants to float a long ways down the runway, and that managing your approach speed is what's most important. Especially with the occasional wind shear at this airport, being located right next to a good sized hill in the foothills.

[magiccarpet]

IMHO the idle RPM is less of a factor than the ineffectiveness of the flaps. I wish to be able to make steeper approaches with notch 2.
Your mileage may very.

[NinerBikes]

Originally Posted by magiccarpet

IMHO the idle RPM is less of a factor than the ineffectiveness of the flaps. I wish to be able to make steeper approaches with notch 2.
Your mileage may very.

What's the difference between a steeper approach, and slipping it sideways or forward to descend? Still learning to fly and land here.

[magiccarpet]

Originally Posted by NinerBikes

What's the difference between a steeper approach, and slipping it sideways or forward to descend? Still learning to fly and land here.

What I meant is, that I wish the RV-12 could descent on a higher gradient with full flaps without gaining much speed. Of course you can slip, but that manoeuver requires more attention in a already critical phase of flight. Not that one can't do it, but the approach would be simply a bit easier.

[rvbuilder2002]

Detailed flight testing has shown that ground idle speeds higher than 1650 definitely impact land performance / distance.

Approach speed of course does as well. Some of the speeds being mentioned here are way above what a standard Vref speed would be for an RV-12.

Keep in mind the fact that the in ground effect full flap stall speed of an RV-12 that is at less than gross weight is below 40 Kts.
Because of that, crossing the threshold and transitioning in to the round out for flare at more than about 50 Kts will result in either a long landing or flat/fast touch down (or both depending on how excessive the speed is).
If you only fly from very long runways and/or don't care about rapid tire wear, I guess it doesn't matter

[rvbuilder2002]

Originally Posted by magiccarpet

What I meant is, that I wish the RV-12 could descent on a higher gradient with full flaps without gaining much speed. Of course you can slip, but that manoeuver requires more attention in a already critical phase of flight. Not that one can't do it, but the approach would be simply a bit easier.

The way to get an RV-12 to descend at a steeper angle is to have the idle speed set properly, and raise the nose to lower the speed.

50-55 Kts IAS (depending on weight)and it comes down pretty good.