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  #21  
Old 11-11-2017, 02:09 AM
az_gila's Avatar
az_gila az_gila is offline
 
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Location: 57AZ - NW Tucson area
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Quote:
Originally Posted by DNeufeld View Post
If I'm fairly close in downwind probably 45 deg looking down at the runway abeam the numbers and pull the power all the way at that point it's a steep descent working the flaps in base and final to make it to the runway with a CS. It's good fun and practice!

I'd say the glide ratio of my 6 with power off is more like 6 to 1 with the CS? Just a guess. Compared to a 172, it's a brick!
Using the numbers in the old CAFE report for a -6A (fixed pitch, O-360)

70 kts - glide ratio 5.8:1 (minimum sink)

92 kts - glide ratio 11.4:1 (maximum L/D)

So it seems like you need to keep the IAS up to get the previously mentioned 11:1 or so glide ratios.

http://cafe.foundation/v2/pdf_cafe_a...inal%20APR.pdf

Not really defined in the report, but I assume no flaps.
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Last edited by az_gila : 11-11-2017 at 02:12 AM.
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  #22  
Old 11-11-2017, 09:51 AM
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Snowflake Snowflake is offline
 
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Quote:
Originally Posted by mbauer View Post
... holding about one foot off until it finally stalls for a three pointer. This is a done using a normal approach distance, altitude pattern for a Cessna 172 or Piper Cherokee.
Ouch. If I held my -6 a foot off the runway until it stalled for a 3-pointer, i'd bang the tailwheel first, and get a heck of a bounce off the mains.

Quote:
Only one post has mentioned using power. Curious if using power on base and final is normal?
Depends whether you want to fly a 3 degree glideslope, or glide it in at the airplane's natural glide angle. I was taught that you should be able to make the runway from anywhere in the circuit if your engine quits, so I try to set myself up so that when I remove power, I won't need it again... So gliding in, no power, for me.
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  #23  
Old 11-12-2017, 07:06 AM
Vac Vac is offline
 
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Location: Niceville, Florida
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Default It depends...

...on airspeed calibration. Suggested numbers should be in CAS and converted to IAS for an individual airplane based on flight test results. Unless two airplanes are configured identically, it's not always apples/apples, even if the airplanes are the same type...

Lots of different techniques out there, and any pattern may have to be adapted to accommodate ATC requirements or other traffic, as appropriate.

One easy, energy efficient visual pattern to fly is ONSPEED, which requires a properly calibrated angle of attack system. Further simplified by flying a fully configured base to final (i.e., landing checks complete prior to "rolling off the perch" and final configuration established), allowing the pilot to simply concentrate on flying the airplane. This technique has the pilot flying a constant, descending 180 degree turn from the "perch/180" to final. If the pilot has a good visual cue and associated altitude for rolling out on final approach while flying an ONSPEED reference, proper energy is ensured when rolling out on final approach. Ideally 12-18 seconds in the grove on final will allow sufficient time for final energy correction and cross-wind assessment (assuming ONSPEED to "slightly fast" in the base turn). Transition to "slightly slow" cue during round-out and then any landing technique is practical, since there is no one right answer for conventional gear types, other than "keep it straight."

ONSPEED works whether the airplane has a glide ratio of 1:1 or 15:1 and assists with establishing a stable approach. The primary factor affecting glide ratio in RV's is the type of prop fitted--there can be appreciable difference between a constant speed airplane and one fitted with a light-weight composite or wood prop optimized for cruise. These aerodynamic differences result in different energy management techniques, including how the pattern is "sized" and visual cues for a particular airplane.

One advantage of AOA reference in the traffic pattern is that ONSPEED AOA is same regardless of gross weight, G-load/bank angle or density altitude. With proper pitch inputs by the pilot to maintain ONSPEED, IAS will vary as required to maintain aerodynamic margin from the stall.

The other handy AOA cue during pattern operations is L/Dmax. It makes a good target speed for downwind. It's roughly coincident with Vfe for half flaps, so it can also assist with configuration management.

AOA and CAS/IAS are best thought of as complimentary concepts, not mutually exclusive. The advantage of AOA reference is that when operating on the back side of the drag curve (as we do every time we takeoff and land), is that AOA always shows the pilot what the airplane is doing relative to the aerodynamic margin (stall limit). Good AOA cues also assist with proper energy control, since there is no requirement to add additional speed to compensate for conditions, which can help preclude carrying too much energy into the landing transition.

If anyone is interested in a more in-depth discussion of applying AOA cues during pattern operations or maneuvering flight, I just posted an update of the training resource document over in the stickies at the top of the safety page. The table of contents is hyperlinked to simplify navigation. CAS references for pattern operations are also included.

Incidentally, may parts of the training manual/syllabus are based on discussion threads just like this one. I'm always interested in improving the transition resources; so if anyone has any questions or inputs, please drop a PM, email or post over on the safety page!

Cheers,

Vac
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  #24  
Old 11-12-2017, 08:46 AM
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Bob Martin Bob Martin is offline
 
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Quote:
Originally Posted by Vac View Post
..Lots of different techniques out there, and any pattern may have to be adapted to accommodate ATC requirements or other traffic, as appropriate.
I agee with Vac.
It appears the original poster is learning to fly the RV and most of us know the beginning is the toughest. Once you know or "feel" the RV it is up to you what technique you use.
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  #25  
Old 11-12-2017, 04:25 PM
fbrewer fbrewer is offline
 
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Location: Leander
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Quote:
Originally Posted by Bob Martin View Post
I agee with Vac.
It appears the original poster is learning to fly the RV and most of us know the beginning is the toughest. Once you know or "feel" the RV it is up to you what technique you use.
You are correct.

I have almost 8 hours of TW time, so I'm almost an expert :-)

This thread has been a good help. Thanks to all.
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  #26  
Old 11-17-2017, 05:48 AM
Doug Eves Doug Eves is offline
 
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Location: Brigden Ontario Canada
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I never did quite understand why anyone would want to be turning (sometimes steep and possibly heavy) close to the ground. ie. Base to Final....especially when there is lots of opportunity to adjust speed , with wings level, on final. Just seems totally unnecessary. One beautiful day I was standing around the Sarnia airport watching an aircraft on base that appeared too slow to me. As I watched him turn final and die , I decided right then and there not to do the same. I encourage all of you to keep some extra speed for that turn because you never know when it could be your "turn"
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  #27  
Old 11-17-2017, 06:17 AM
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Sam Buchanan Sam Buchanan is offline
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I prefer an oval turn from downwind (which is much closer than what we often see) to final. The key is to maintain *proper* speed, extra speed just complicates the arrival and creates the need to either bleed it off on final or land long.
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  #28  
Old 11-17-2017, 09:23 AM
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ChiefPilot ChiefPilot is offline
 
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Quote:
Originally Posted by Doug Eves View Post
I never did quite understand why anyone would want to be turning (sometimes steep and possibly heavy) close to the ground. ie. Base to Final....especially when there is lots of opportunity to adjust speed , with wings level, on final. Just seems totally unnecessary. One beautiful day I was standing around the Sarnia airport watching an aircraft on base that appeared too slow to me. As I watched him turn final and die , I decided right then and there not to do the same. I encourage all of you to keep some extra speed for that turn because you never know when it could be your "turn"
I prefer a short approach over base / final when possible - it keeps the runway nicely in sight at all times. Turning close to the ground is no big deal for me. And, as Sam points out, extra speed is bad. Proper speed (or proper AoA) is the goal.
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  #29  
Old 11-17-2017, 09:41 AM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by ChiefPilot View Post
I prefer a short approach over base / final when possible - it keeps the runway nicely in sight at all times. Turning close to the ground is no big deal for me. And, as Sam points out, extra speed is bad. Proper speed (or proper AoA) is the goal.
Excellent point on the AOA, it is my primary instrument when making the 180 turn from downwind to final. The airplane doesn't care how close it is to the ground as long as we keep the wing happy.
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Last edited by Sam Buchanan : 11-17-2017 at 09:44 AM.
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  #30  
Old 11-17-2017, 10:04 AM
luddite42 luddite42 is offline
 
Join Date: Mar 2010
Location: USA
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Quote:
Originally Posted by Doug Eves View Post
I never did quite understand why anyone would want to be turning (sometimes steep and possibly heavy) close to the ground. ie. Base to Final....especially when there is lots of opportunity to adjust speed , with wings level, on final. Just seems totally unnecessary. One beautiful day I was standing around the Sarnia airport watching an aircraft on base that appeared too slow to me. As I watched him turn final and die , I decided right then and there not to do the same. I encourage all of you to keep some extra speed for that turn because you never know when it could be your "turn"
Assuming you're qualified, go up in your RV at altitude and replicate base to final turns at lower and lower airspeed and you'll see how hard you have to work and how out of whack you really have to be to produce a stall/spin/spiral departure during a normal turn. Do you actually have spin experience? Many pilots who lack comfort level and experience in this area are often overly concerned about stalling and operating near their perceived "edge of the flight envelope". This causes them to fly with excessive speed in the pattern and on final. Your mind would have to be fatally absent or distracted to allow yourself to get anywhere near this condition even at moderate bank angles in the pattern. It's nothing to fear. The fact that you're thinking about energy management each time you make this turn means you're engaged. But as others have mentioned, there is no need for excess energy. Speed is not life. Proper energy management and paying attention is life.
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