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  #11  
Old 02-11-2019, 12:10 PM
lr172 lr172 is offline
 
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Originally Posted by RFazio View Post
Tim,

I fly coupled approaches in my 6 a lot. I have a Dynon system. I have found that in the RV6, 90 is a bit slow. To me, when I am trying to maintain 90 knots, the plane is like a boat just about on plane. You are heading down hill and it wants to speed up. You slow the engine and it slows, then too much. So you add power again. You speed goes up and down. I fly the approach at 110 to 120 knots, no flaps. Then as I get down to below 1000 ft or so AGL, I pull power, and then add flaps when I have the runway in sight. With these planes landing a little hot or long is not a problem. I’m still turning off most runways at the mid point. The plane is just so much more stable at 120 knots, it’s one less thing to worry about. Like others have said I had to turn up my gain and sensitivity a lot also.

Another thing about RVs and auto pilots. Since the plane has such a broad speed range, setting the autopilot to work right at cruise means it might be sluggish at approach speeds. Setting it for approach speeds means it may be a little twitchy at cruise. I have mine set for approach speeds, 120 knots. And it is a little quick at cruise, but I like it that way.

RF
I concur, but caution the need for practice. It is very easy to drop speed and set up when breaking out at 500+' but you don't want to learn how to do it on the gauges when breaking out at minimums with turbulence. The needles get sensitive that close and increase the challenge of slowing down 40 knots, not to mention the likelihood of low visibility and many brain cycles dedicated to finding the runway. I imagine it is doable after breaking out at 200, but you don't have a lot of time to get it done and would be tough to shed 40 knots with an FP. It is easier if you typically do steep approaches.

When doing low clg approaches, I tend to slow down some time after the FAF (maybe 1000 AGL). Yes, it is more effort to hold the GS at 90 knots than 130, but I don't want the extra effort of slowing down at low altitudes with a limited amount of time. I tend to hand fly most approaches, so not doing the throttle dance necessary on coupled approaches.

Larry
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Last edited by lr172 : 02-11-2019 at 12:18 PM.
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  #12  
Old 02-11-2019, 01:06 PM
BobTurner BobTurner is offline
 
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Originally Posted by lr172 View Post
I concur, but caution the need for practice. It is very easy to drop speed and set up when breaking out at 500+' but you don't want to learn how to do it on the gauges when breaking out at minimums with turbulence. The needles get sensitive that close and increase the challenge of slowing down 40 knots, not to mention the likelihood of low visibility and many brain cycles dedicated to finding the runway. I imagine it is doable after breaking out at 200, but you don't have a lot of time to get it done and would be tough to shed 40 knots with an FP. It is easier if you typically do steep approaches.

When doing low clg approaches, I tend to slow down some time after the FAF (maybe 1000 AGL). Yes, it is more effort to hold the GS at 90 knots than 130, but I don't want the extra effort of slowing down at low altitudes with a limited amount of time. I tend to hand fly most approaches, so not doing the throttle dance necessary on coupled approaches.

Larry
+1
Not just low ceilings but also low visibility. Remember that if itís really 1/2 mile vis, then at 200í agl you canít see the runway - just the approach lights. Thatís not a great time for reconfiguring the airplane.
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  #13  
Old 02-11-2019, 08:06 PM
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TJCF16 TJCF16 is offline
 
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You all have good points. I personally have higher minimums than published. I am going to try some different configuration settings. I just have to dial the auto pilot in. I would think in todayís software you could set the autopilot settings different on approach then cruise. Letís face it, if you press the APR button on the autopilot it should be able to say hay we are now going to use approach configuration not cruise. Maybe wishful thinking!
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  #14  
Old 02-11-2019, 10:18 PM
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Ed_Wischmeyer Ed_Wischmeyer is offline
 
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When you hand fly an approach, you have a feeling for what the plane is doing, and you can decide how much elevator and how much throttle you want to use for corrections. But, with the autopilot flying pitch to track the glideslope, you have to adjust the throttle using only airspeed. This can be really ugly if there are updrafts and downdrafts.

Remember your first instructor telling you not to chase the airspeed indicator? That's what can happen here.
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  #15  
Old 02-11-2019, 10:22 PM
lr172 lr172 is offline
 
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Originally Posted by TJCF16 View Post
You all have good points. I personally have higher minimums than published. I am going to try some different configuration settings. I just have to dial the auto pilot in. I would think in today’s software you could set the autopilot settings different on approach then cruise. Let’s face it, if you press the APR button on the autopilot it should be able to say hay we are now going to use approach configuration not cruise. Maybe wishful thinking!
Until they develop an AP that has control of the throttle, it is wishful thinking. Some pilot intervention will be required to maintain a desired speed. If youupgrade to an airbus, then you can just press a button and expect the plane to land itself. Not so much in a RV.

Larry
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Last edited by lr172 : 02-11-2019 at 10:26 PM.
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  #16  
Old 02-11-2019, 10:32 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by Ed_Wischmeyer View Post
When you hand fly an approach, you have a feeling for what the plane is doing, and you can decide how much elevator and how much throttle you want to use for corrections. But, with the autopilot flying pitch to track the glideslope, you have to adjust the throttle using only airspeed. This can be really ugly if there are updrafts and downdrafts.

Remember your first instructor telling you not to chase the airspeed indicator? That's what can happen here.
This is why I don't use the AP. The only time I got scared on an approach was when I tried letting the AP fly it. I thought the same as the OP. I caught myself looking away a bit longer than normal (thought the AP was doing the work) and when I looked again I was down to 75 mph. Before yelling at me, It was a practice approach on a beautiful VFR day. Not even wearing a hood. I was shocked how fast I want from 105 to 75. Pretty much the last time I used it for an approach. I now know better, but still feel better doing my own.

That said I was tired one day at the end of a flight and it was quite bumpy. I was glad that I had practiced with the AP a bit more, as I felt better letting George fly the approach that day. As long as you stay active with the throttle, they can fly them pretty well. The key is to keep the throttle changes in harmony with the AP's pitch changes.

Larry
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Last edited by lr172 : 02-11-2019 at 10:40 PM.
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  #17  
Old 02-12-2019, 06:11 AM
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Brantel Brantel is offline
 
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Quote:
Originally Posted by TJCF16 View Post
You all have good points. I personally have higher minimums than published. I am going to try some different configuration settings. I just have to dial the auto pilot in. I would think in today’s software you could set the autopilot settings different on approach then cruise. Let’s face it, if you press the APR button on the autopilot it should be able to say hay we are now going to use approach configuration not cruise. Maybe wishful thinking!
Respectfully, the software works great as is, you must properly tune it.

A properly applied, installed, and tuned Garmin AP system will likely perform equal or better than the typical certified system costing many orders of magnitude more.

The RV9 should be easy to tune in due to its increased stability. Have you spoken with TeamX yet?
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Last edited by Brantel : 02-12-2019 at 08:21 AM.
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  #18  
Old 02-12-2019, 08:17 AM
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I like to fly each approach as I would get visual at the minima, that way you always do the same and when you actually break out just before "go around" you will do what you always do to land and not something special.

So if you have decided that legal minima plus 100 feet is your minima, then stay on the AP until then even if you get visual at 1000 agl
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  #19  
Old 02-12-2019, 08:26 AM
BillL BillL is offline
 
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Quote:
Originally Posted by Brantel View Post
Respectfully, the software works great as is, you must properly tune it.

A properly applied, tuned, and installed Garmin AP system will likely perform equal or better than the typical certified system costing many orders of magnitude more.

The RV9 should be easy to tune in due to its increased stability. Have you spoken with TeamX yet?
The AP absolutely must be tuned for your airplane. G3X guys will help you with the correct documents for your panel/avionics. It will make all the difference in the world. Otherwise it can be very challenging and distracting.

The procedure is stepwise and clear. Be sure you pay attention to your set speeds for auto trim too, if you have it. A little off on the tuning and trim setting mismatch and the trim can lag behind aircraft conditions and overload the servo, it hits the torque limit and BAM . . . suddenly you have a nose down 3000fpm.
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