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Ed Cesnalis

No flaps, and low power settings in the mountains

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In 2018 I continue to fly mostly in the high Sierra.  I've been waiting to have my new flap circuit board installed since last year and currently operate without flaps.  I have been a long time advocate of using flaps and minimum speed landings.  My opinion on that isn't changing but I do understand why so many prefer minimum flap landings, its just too easy (as long as you don't get gusted on rollout).  Its on my -6 take-offs that I sense the vulnerability every time.  The period where my mains are on the ground and I have flying speed screams vulnerability to me.

The photo below was shot at 13,000'+.  I now like to descend into position and through canyons at low power settings and I'm taken by how rough running my Rotax is when I get well below the 5,000RPM range.  I wonder if a carb balance might help?  I mind it less in the pattern than I do in the big canyons.

Bear Creek Spire-15.jpg

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3 hours ago, FlyingMonkey said:

Landings at -6° to me feel VERY fast. 

There is ample reason for that.?

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In the interim why don't you manually set them at zero flaps? Two ways to do it.

Have you tried the flap override on your flap switch which means going all the way around clockwise with the switch to the 9 o'clock position. Then you can move the flaps up or down as needed manually. If the system is totally gone then hook up the program switches and reset to zero.

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Take offs may get a little iffy in -6 now that the temps are warming up and you already live at high elevation.

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1 hour ago, Roger Lee said:

Take offs may get a little iffy in -6 now that the temps are warming up and you already live at high elevation.

no lie

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Ed, when you fly low speed in the canyons, isn't it risky to not have full flaps for climb out in case you need it?  You are already compromised for climb out due to (low)power due to altitude.  I would think there's some anxious moments where you are wanting altitude increases but your CT isn't able to provide it during your flights.  Take offs at -12 flaps at airports with short runways and mountains nearby would be a white knuckle ride for me.

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4 hours ago, Runtoeat said:

Ed, when you fly low speed in the canyons, isn't it risky to not have full flaps for climb out in case you need it?  You are already compromised for climb out due to (low)power due to altitude.  I would think there's some anxious moments where you are wanting altitude increases but your CT isn't able to provide it during your flights.  Take offs at -12 flaps at airports with short runways and mountains nearby would be a white knuckle ride for me.

Therefore, it begs the question . . . what is Vx (best angle of climb), with -12° flaps, at max gross weight? There is a definite answer to that question.

Under those flight conditions, that seems to be something one would want to know.

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Bill, you're right.  This takes us back to the "discussion" about using flaps for altitude increases.  I rely on my friend, Phil Wade, for this advice.  On his last trip to Page and encountering mountains, Phil  used "0" flaps @ 65 kts. and when no longer able to gain altitude, went to 15 flaps @ 60 kts. for Vx to gain altitude.  I have since flown with Phil here in the flatlands and he demonstrated this at 11,000' and had me repeat.  It works for me too.  What are your thoughts?

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58 minutes ago, Runtoeat said:

. . . . . This takes us back to the "discussion" about using flaps for altitude increases.  I rely on my friend, Phil Wade, for this advice.  On his last trip to Page and encountering mountains, Phil  used "0" flaps @ 65 kts. and when no longer able to gain altitude, went to 15 flaps @ 60 kts. for Vx to gain altitude.  I have since flown with Phil here in the flatlands and he demonstrated this at 11,000' and had me repeat.  It works for me too.  What are your thoughts?

Very simply put . . . Vx is a good speed to clear terrain/ostacles in the shortest distance. Only thing is . . . climb rate is less than Vy, so it takes longer to get there, but you won't eat up as much real estate trying to do it.

For the CTSW, I wish Flight Design would publish climb performance charts for all flap settings. That would minimize the debate and endless arguing over the best techniques to use.

The charts are there in Europe. Flight Design, for some unknown reason, decided not to publish them for end users.

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4 hours ago, WmInce said:

Therefore, it begs the question . . . what is Vx (best angle of climb), with -12° flaps, at max gross weight? There is a definite answer to that question.

Under those flight conditions, that seems to be something one would want to know.

Vx isn't an issue for me in the big Sierra Canyons.  There is so much wind shear that I loath to get that slow or anywhere close to it.  I fly 200lbs under gross when working up high and have good rate of climb up to and above 15,000 and I keep my indicated air speed at 95kts if I can.  Below 85 I get anxious.

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Not to stir the pot because I know this has almost come to blows in other threads, but shouldn't climb rate be highest at all altitudes with the lowest drag setting (-6 / -12 in our case) ? 

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Bill and Ed, thanks for your comments.  This adds to my understanding of options available to us for gaining altitude.  Ed, I still am trying to wrap my head around you taking off with -12 flaps at high altitude if there's obstacles close by that must be cleared (i.e., High Mountains!)

Andy, do I recall you actually testing this out?  At least I recall you cranking some numbers on it.  I think you're correct for "rate" of climb but for achieving best altitude gain over the shortest distance traveled I think lower flaps (i.e., "0" or "15") @ recommended Vx speed is best.

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1 minute ago, Runtoeat said:

Bill and Ed, thanks for your comments.  This adds to my understanding of options available to us for gaining altitude.  Ed, I still am trying to wrap my head around you taking off with -12 flaps at high altitude if there's obstacles close by that must be cleared (i.e., High Mountains!)

7000' runway at Mammoth, and the approaches look flat to me...

https://www.google.com/maps/@37.6240556,-118.83875,1826m/data=!3m1!1e3

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12 minutes ago, FlyingMonkey said:

7000' runway at Mammoth, and the approaches look flat to me...

https://www.google.com/maps/@37.6240556,-118.83875,1826m/data=!3m1!1e3

From the east its even uphill approaching but departing to the west is more like rapidly rising terrain.  Flying the runway heading goes to 13,000' in about 12 miles.

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18 minutes ago, Runtoeat said:

Bill and Ed, thanks for your comments.  This adds to my understanding of options available to us for gaining altitude.  Ed, I still am trying to wrap my head around you taking off with -12 flaps at high altitude if there's obstacles close by that must be cleared (i.e., High Mountains!)

Andy, do I recall you actually testing this out?  At least I recall you cranking some numbers on it.  I think you're correct for "rate" of climb but for achieving best altitude gain over the shortest distance traveled I think lower flaps (i.e., "0" or "15") @ recommended Vx speed is best.

50' trees at the end of the runway are the type of obstacles that you need Vx for.  High mountains, even close by are better to fly clean.  If the angle is too steep then you orbit or s turn or work lift.  It's silly to point at the highest point in your direction, then use a steep angle and labor over.  Far better to put your nose down and find a path at a much higher speed, it just won't be a strait line.  As you test different headings and positions in the canyons and positions relative to the ridges you will know where there is lift to work and drift is to be concerned about.

The big risk isn't that you can't out climb the terrain because even at the very last 2nd you can always turn away (you can't let yourself be trapped). The big risk comes from constantly turning or doing long sustained turns, where you are blinded by the banked wing and there is terrain to fly into or even more insidious, drift into while you are blind.  I visualize the turn and its exit and make sure it takes up no more than 50% of the time I have to remain clear of terrain in that turn.  Synthetic Vision can be confirming here but that's complicated and more useful in very big canyons.

I crossed 8 mountain ranges this morning and never got within 1,500 of the high points, small amounts of deviation gets you around things and thats better than even Vy climbing.

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Ed,

You are talking technique, which is quite alright, but I am talking about tested performance numbers. What does the book say about the best climb rates and angles for a given condition? That would be nice to know, at least for planning.

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2 hours ago, Runtoeat said:

Andy, do I recall you actually testing this out?  At least I recall you cranking some numbers on it.  I think you're correct for "rate" of climb but for achieving best altitude gain over the shortest distance traveled I think lower flaps (i.e., "0" or "15") @ recommended Vx speed is best.

Yeah, I did some hypothetical numbers.  I think I found that more flaps at lower speed could give more time in the climb before reaching an obstacle, which could get you to a higher altitude by the time you got there.  But in pure climb rate with no obstacles present you definitely want to be at minimum flaps.

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10 minutes ago, FlyingMonkey said:

Yeah, I did some hypothetical numbers.  I think I found that more flaps at lower speed could give more time in the climb before reaching an obstacle, which could get you to a higher altitude by the time you got there.  But in pure climb rate with no obstacles present you definitely want to be at minimum flaps.

At all flap settings and weights, there is a best rate and best angle climb speed. I would like to see those numbers (for CTSW).

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4 hours ago, Runtoeat said:

Bill and Ed, thanks for your comments.  This adds to my understanding of options available to us for gaining altitude.  Ed, I still am trying to wrap my head around you taking off with -12 flaps at high altitude if there's obstacles close by that must be cleared (i.e., High Mountains!)

Andy, do I recall you actually testing this out?  At least I recall you cranking some numbers on it.  I think you're correct for "rate" of climb but for achieving best altitude gain over the shortest distance traveled I think lower flaps (i.e., "0" or "15") @ recommended Vx speed is best.

It was the other Andy that revealed that Vx was determined by comparing drag and available power profiles for each flap setting.

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BTW it was a disconnected carb equalization tube to the airbox causing the roughness at low power settings.

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7 hours ago, Ed Cesnalis said:

 

Vx isn't an issue for me in the big Sierra Canyons.  There is so much wind shear that I loath to get that slow or anywhere close to it.  I fly 200lbs under gross when working up high and have good rate of climb up to and above 15,000 and I keep my indicated air speed at 95kts if I can.  Below 85 I get anxious.

Ed 95kt. or even 85kt is still fairly fast in terms of TAS at that alt.

I realise stall is based on IAS but you still have a good margin of at least 40kt. So is your need to keep the speed so high for other reasons like inertia to fight unexpected shear?

Ps never flown my a/c at 15,000 so I wouldn't know.

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