Sport Pilot Talk

Jon V · Joined: 21 Apr 2011 Posts: 156 Location: Dallas...

Last week I posted about how I successfully landed on my first try after a 6 year hiatus. This is the other side.

For my last lesson my CFI had me try 180 degree power off approaches instead of the normal (powered) approach I've always used. What a mess!

Two go-arounds in three attempts, and when I finally landed I think I managed to touch down halfway down a 7000' runway. It was ugly.

So...tips or advice? This is a new maneuver to me and in perfect honesty I don't think I'll use it in regular flying but I'm game for anything that will build skill and judgment.

For clarity: I've done power off approaches and landings as part of emergency landing practice, years ago, but that was an energy retention exercise (hold on to every joule until 100% certain of reaching the chosen runway, then burn off the extra with a spiral and/or slip) that came with a side helping of "in an actual emergency you won't have even this much energy to burn off - if you are really high at idle, you may be coming short of the runway in an emergency") whereas this is a position and glide judgment exercise it seems like you would only do with an engine to pull you out when you misjudged things.

bitten192 · Joined: 21 Dec 2009 Posts: 61 Location: RICHLAND WA USA

G3 has a 17:1 glide ratio. Power off approaches are tricky depending on wind. Learn how to slip and fishtail if you are high on final.

http://www.pilotfriend.com/training/flight_training/fxd_wing/slip.htm

eb

Jon V · Joined: 21 Apr 2011 Posts: 156 Location: Dallas...

If I'm thinking through this correctly, we had two or perhaps three problems going on.

First, we were overestimating the wind. It's been in the 16-20kt+ range (at least in the gusts) on every other flight we've made, and we have cancelled quite a few flights due to over-25kt headwinds. The power-off approach practice was on the one day with winds barely reaching 5kts.

Second, sink rate. We were misjudging it badly. I say "we" because after my second go-around my CFI said "lemme try one" (loose translation) ... and proceeded to, despite a long limit-of-rudder-authority slip, land very long himself.

Third, and this is an area where I'm trying to sort out seemingly conflicting information, is airspeed and configuration. My CFI has been holding me to airspeeds considerably higher than POH, and flap settings both higher and lower than POH. E.g.

From POH: "When entering final, we recommend establishing an airspeed of 60 to 63 mph (52 to 55 kts) and extending flaps to the 40° position."

From CFI: "I don't want to see the speed below 65 on final, and don't use more than 30° of flaps."

That's part of a pattern. It isn't just this one CFI either. Another CFI in talking about the Remos said, "The POH says to raise the nose at 35. Don't. Rotate at 55." I'm not arguing right or wrong (55 seems like a reasonable speed to me, paved runway and all) but I haven't figured out the pattern.

dstclair · Joined: 06 Mar 2008 Posts: 212 Location: Allen, TX

Quote: From CFI: "I don't want to see the speed below 65 on final, and don't use more than 30° of flaps."
My Sting S3 has a glide ratio of 16:1 which is about the same as the Remos. I would float 1000' down the runway if I was at 65kts on final. 55kts is what I use.

I would also suspect that you are wheel-barrowing down the runway on take-off if you waiting until 55 kts. The plane is flying even though the wheels are on the ground. I can see keeping the Remos on the ground a little longer on gusty days but this seems more than a bit high.

zaitcev · Joined: 05 Jan 2010 Posts: 258 Location: Albuquerque, NM

I found flaps on Remos GX to be extremely effective in creating the necessary drag. I have not been in a situation where a slip was required to meet the touchdown point yet. Mind, I have not performed an engine-out landing to a runway in it. Also, G3 may be different from GX. Still, it may be something to look into, e.g. detect overshoot early, go on flaps early, see if you shoot right. Usually in emergency one wants to extend the glide, so flaps are not used. But once the landing zone is identified, one needs to hit it and not trees behind it, or so I think. There is juice in battery for flaps even with dead engine.

Jon V · Joined: 21 Apr 2011 Posts: 156 Location: Dallas...

Quote: I would also suspect that you are wheel-barrowing down the runway on take-off if you waiting until 55 kts.

55 MPH / 48 kts.

POH says:
Quote:
* After reaching a speed of about 35 mph (30 kts), gently raise the nose.
* The aircraft will be airborne after exceeding a speed of about 46 to 52 mph (40 to 45 kts)

OTOH, they generally assume you will be using an unpaved runway and include a few offsets for pavement instead of treating paved as "normal" and including offsets for unpaved.

Quote: Usually in emergency one wants to extend the glide, so flaps are not used.

This was supposed to be a try at a "Power-Off Accuracy Approach" ... though inaccuracy would be more accurate. Airplane Flying Handbook page 8-21 through 8-23 plus or minus. It bears little or no resemblance to the emergency power-off landing practice I am familiar with.

As far as I know the GX and G3 have different airfoils. The POHs airspeeds are pretty noticeably different, e.g.:

G3 Vx: 58 to 64
GX Vx: 68 to 75

G3 Vy: 72 to 76
GX Vy: 85 to 88

G3 Vapproach: 60 to 63 mph
GX Vapproach: 75 to 80 mph

G3 says best glide is at 60 MPH with 15 degrees of flap
GX says best glide is 75 mph 0 flap

That's based on the latest POH files on the Remos web page.

Kinda makes a person wonder.....

zaitcev · Joined: 05 Jan 2010 Posts: 258 Location: Albuquerque, NM

Jon V wrote: As far as I know the GX and G3 have different airfoils.
I see. Sorry for the noise.

Jon V · Joined: 21 Apr 2011 Posts: 156 Location: Dallas...

There was signal there too. :)

I'm kinda torn. My normal approaches are solid ("haven't messed one up in years" ;)) which means it makes sense to practice something different. OTOH power-off approaches aren't part of the PTS for Sport Pilot and I'm not sure they can be done without a heck of a headwind if you aren't using the full secondary controls or flying to the POH numbers. I haven't seen one demonstrated successfully.

I think next time I have a lesson scheduled but the weather sucks and I can't fly (which will probably be this Thursday) I'll sit down with the CFI, the POH, the FAA A.F.H., and ask him to explain the decisionmaking process that has us flying final faster than either the POH (60) or the A.F.H. "rule of thumb" 1.3Vs0 (59), not using recommended flaps, etc. Hopefully it will cement in my mind a good way of approaching these decisions for myself. I suspect there are some thumbs on the scale (e.g. someone added .5 of gust factor for the day a previous CFI was checked out in the G3) that are no longer attached to any body, but either way I want to understand.

Jack Tyler · Posted: Tue May 24, 2011 4:35 pm Post subject:

Jon, what was the a/c you were most familiar with in your previous flying? The way you talked about the 'past vs. present' made me flash, first, on the significant difference in glide ratio between (I'm guessing now...) a Part 23 a/c you were most familiar with formerly and these slipperier composite LSAs so common today. Your descriptions (of needing to go around or landing long when initially keeping more speed on the plane than recommended) is exactly the comment I hear from folks transitioning to the RV-12 (from Part 23 a/c).

Another reaction I had to the instructional sequence you were describing is that it sounded overly cautious on your CFI's part. He's there (and I'm out here in cyberspace) so I'm only surmising...but my primary CFI never asked me to put more energy in the airframe than was normal prior to doing loss-of-engine landing practices. In fact, this was a common competition my son and I would have when flying around the pea patch together. The goal was always to put the plane on the numbers after loss of power, while doing a normal approach up to that point and while varying the location in the pattern of loss of power. We would never put the plane into an unusual configuration - one that doesn't reflect the conditions you normally face - adjusting the approach from what one is accustomed to using.

One last thought: As it happens, I've had to deal with two real loss of power landings. One was while flying over the coastal Atlantic off an uninhabited South Carolina barrier island and the other was while on an instrument flight plan near Tampa International. In both cases, it was very much a case of the 'real thing' being a non-event and working out well simply because we handled it very much like the practice 'dead stick' landings, which in turn were practiced from a normal approach until loss of power. My observation is that, if practiced regularly, you'll likely fly what you practiced. I'd fly the recommended speeds and adjust the approach. Nice to have that bountiful glide ratio. :lol:

Jim Stewart · Joined: 12 Oct 2006 Posts: 259

I fly a CTSW and I try to fly every approach power off.

The target starting point is 75 knots abeam the numbers at pattern altitude. I cut the throttle to idle, hold the nose up until airspeed decays to 65 knots and add 15 degrees of flaps. I hold 65 knots and turn base around 750-800 feet. On base, I hold the nose up until airspeed decays to 55 knots and I go to 30 degrees flaps. I fly the rest of the approach at 55 knots and throttle at idle. On final, I compare a mark on the windscreen with a point on the runway. If the two points are stationary relative to each other, that's where I'm going to flair. Rarely I'll need to add a little power to keep from coming up short.

In my humble opinion, 65 knots is 10 knots too fast unless your plane is significantly different from mine or it is a gusty day. At 55 knots, after I flair I have 5 seconds of energy left before my wheels need to be on the ground. At 65 knots it will be way longer. The more you work on this the easier your short and soft field landings will be.

Jon V · Joined: 21 Apr 2011 Posts: 156 Location: Dallas...

Jack Tyler wrote: Jon, what was the a/c you were most familiar with in your previous flying? The way you talked about the 'past vs. present' made me flash, first, on the significant difference in glide ratio between (I'm guessing now...) a Part 23 a/c you were most familiar with formerly and these slipperier composite LSAs so common today. Your descriptions (of needing to go around or landing long when initially keeping more speed on the plane than recommended) is exactly the comment I hear from folks transitioning to the RV-12 (from Part 23 a/c).

First and best: AMD CH2000 - that's what I soloed in.
Later: 172

CH2000 approaches about 1.15 times as fast as the Remos (by the POH). In other words, both POHs suggest final at about 60 but the Remos is 60 MPH and the CH2000 is 60 Kts. The Remos is actually the faster plane if you are looking at cruise/top speeds.

Quote:
Another reaction I had to the instructional sequence you were describing is that it sounded overly cautious on your CFI's part. He's there (and I'm out here in cyberspace) so I'm only surmising...but my primary CFI never asked me to put more energy in the airframe than was normal prior to doing loss-of-engine landing practices.

That's part of what I'm concerned about. He's new to LSAs in general. I don't know how much time he has spent in slow planes. OTOH, he got his numbers (speed, max flaps, etc) from another CFI who has taught in the Remos quite a bit.

Quote:
In fact, this was a common competition my son and I would have when flying around the pea patch together. The goal was always to put the plane on the numbers after loss of power, while doing a normal approach up to that point and while varying the location in the pattern of loss of power. We would never put the plane into an unusual configuration - one that doesn't reflect the conditions you normally face - adjusting the approach from what one is accustomed to using.

Given my experience from last week, you'd win. :)

Quote:
One last thought: As it happens, I've had to deal with two real loss of power landings. One was while flying over the coastal Atlantic off an uninhabited South Carolina barrier island and the other was while on an instrument flight plan near Tampa International. In both cases, it was very much a case of the 'real thing' being a non-event and working out well simply because we handled it very much like the practice 'dead stick' landings, which in turn were practiced from a normal approach until loss of power. My observation is that, if practiced regularly, you'll likely fly what you practiced. I'd fly the recommended speeds and adjust the approach. Nice to have that bountiful glide ratio. :lol:

A good thought. I just need to figure out where the numbers are coming from and understand what's going on. I can't even really say they are right or wrong...only that they are so different than the POH that I don't know how they were derived.

bitten192 · Joined: 21 Dec 2009 Posts: 61 Location: RICHLAND WA USA

The REMOS G3 does not fly like a CTSW or a CH2000 or C152 etc. It flys like a G3. You should follow the numbers in the POH. It lands slow and floats. You may never be able to land on a spot but you will usually make the first turn off. On low wind situations here's what works for me. Down wind trim for 70 mph, 2/3 flaps (all speeds are in mph, not knots, abeam the numbers power at idle, full flaps and full nose up trim 65 mph, start descent and at 500 feet agl turn to base, slow to 60 mph. Gradually slow down to 50 mph over the numbers and at round out you will be at about 40 mph. The G3 lands slow. By the way, the max cross wind component is 17 mph and max wind speed for take offs is 28 mph (about 25 knots). If there are faster aircraft behind you in the pattern, advise them or the control tower if appropriate to land ahead of you. I once had a UAL behind me have to go around at Billings MT. Very embarrassing for the control tower and expensive for the airline.

Ernie B
REMOS G3 N192RA
CFI

Jon V · Joined: 21 Apr 2011 Posts: 156 Location: Dallas...

Grrr... that is SO different than how I'm being told to fly the G3.

I'm in a rotten position. Most of me knows that I'm a total noob to flying and have no real judgment about such things, but a little part of me thinks that the speeds we are flying just don't feel right.

I have a lesson scheduled for tomorrow. I'm going to start with a good positive talk with my CFI, POH in hand, and see if we can figure out the difference between the numbers and how we're flying. If it's that he's not comfortable with that sort of flying...well, I don't know what I'll do. Frankly I'm leery of adding another CFI to my logbook, simply because it has got to raise questions about how teachable I am to any new CFI that looks at it... I've already got 5 or so names in there.

drseti · Joined: 28 Nov 2009 Posts: 1390 Location: Lock Haven PA

Jon V wrote: I'm going to start with a good positive talk with my CFI, POH in hand,

Minor point of terminology: S-LSAs don't have a POH (certified aircraft do), but rather an AOI. So, what's an AOI? Just a POH for an LSA! :wink:

Quote: Frankly I'm leery of adding another CFI to my logbook, simply because it has got to raise questions <snip> I've already got 5 or so names in there.

I wouldn't think that would matter. Would anybody be alarmed if you had logged time in 5 different types of aircraft? I should hope not -- you're just trying different ones out to see which one fits you best. Why should CFIs be any different?

drseti · Joined: 28 Nov 2009 Posts: 1390 Location: Lock Haven PA

bitten192 wrote: You should follow the numbers in the POH.

Always a good place to start (POH or AOI as the case may be -- see my prior post). But what if the plane doesn't have documented numbers -- or has been modified out of original specs?

This isn't all that farfetched. I've flown a lot of antiques and homebuilts for which the book numbers are suspect, if they exist at all. Even my S-LSA has been modified (with a Letter of Authorization from the manufacturer, of course), by the addition of vortex generators, which change the stall speed, hence the landing numbers. So, here's what I do when the numbers are questionable:

Take the plane up to altitude, and do power-off stalls in the landing configuration. Do several, and determine what Vso really is. Then, try for 1.4 Vso on downwind, 1.3 Vso on final. This may well yield slower (or maybe even faster) numbers than the book calls for, but give them a try and see what happens. If you get too much sink, or float, you can then tweak the numbers for what works.

Bear in mind, this is not something for the student pilot to try (especially not by himself or herself) -- the CFI should have done this, and know the numbers to teach the student. Blindly teaching somebody else's published or verbalized numbers seldom results in one getting optimum performance out of the plane.

FWIW, after installing those VGs, I ended up having to lower my approach speed considerably below the book values. I could still land at the published numbers, but I tended to float way down the runway.