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N284DG flight behavior - comments?

Dgamble

Dgamble

Well Known Member
A few things I've noticed after three flights and a dozen landings:

- Fairly deep drop of the right wing in stalls. After the first one, I concentrated on keeping the ball centered but it still drops the right wing.
- I'm making full-stall landings, which may or may not be the cause of this: I'm pretty much thumping the nose wheel down on landings. Is this a technique thing? Roll it on instead of stalling it on?
- It takes a lot of nose down trim for level flight, more than seems would be normal. I ran the threaded pushrod on the trim arm (the one that attaches to the stab) in as far as it will go, which seems to be the limit of available adjustment.
 
The landings should be on the mains only. In roll out hold the nose wheel off the ground with the evelator until it would hold it off any more.

Are you using full flaps?

Do you have wheel pants installed?
 
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Full flaps yes, wheel pants no.

I'm going to try letting the mains touch pre-stall later today, if the weather cooperates. Landing in a stall kinda implies that there's not a whole lot of lift (well, any at all) left in the wing, but I thought there might be enough left in the stab to keep the nose up. Stall speed is soooo slow, though, that maybe that simply isn't the case.
 
Try this technique!

Dave when you are doing your stalls its hard to critique them when we are not in the plane. There are a lot of variables like are you talking about power on stalls or power off stalls? Do you have your flaps extended? Are you trying to use you ailerons or your rudders for control when you recover, etc.:confused:
On your takeoffs and landings you want to use a modified softfield technique to reduce wear and tear on your nose wheel and strut. Remember your nose wheel strut has no built in shock absorption like a gas strut on a factory built plane
other than the flexing of the tubular strut. See this video link of Mitch Locke taking off in the blue demonstrator. Notice his nose wheel during his takeoff roll.
http://www.youtube.com/watch?v=om1_ln6cePs
Here is another link to the Teen flight video of a takeoff and also watch the landing to see the reverse of the takeoff. This is what Larry is talking about.
The Takeoff is at the 50 second mark. The landing is right after the takeoff at the 1min 16 second mark. Study the nose wheel closely in each video. "I'm pretty much thumping the nose wheel down on landings". Imagine 500 hours of this kind of landings on your nose wheel strut.:eek: Not to beat up on you just saying for other readers.:rolleyes:
http://www.youtube.com/watch?v=haqgyE25YbI
 
Dave,

I had the same right wing drop when doing stalls in my -12 and just thought it was the airplane. I concentrated on keeping the ball centered perfectly and it still did the same thing. After a while I quit worrying about it and just thought that was the way it was.

While flying with Mike Seager to get transition training for my -4 I learned that I was wrong. I had the same problem in his -7 and he told me to try again. I did, with the same result. I looked at him quizzically and asked "Huh?" I said I was keeping the ball centered and he responded that how do I know the ball is accurate? He told me that if I work at it I can get feet positioned so that it will stall straight ahead, and I could.

At that time I remembered that the ball in the Dynon wasn?t perfectly centered. With the airplane level on the ground the ball was over to the right side bar and even a little bit of the ball was behind the bar. When I used that as "centered" things worked a lot better.

As for the landings, I always "fly it on" a couple of knots above the stall speed. When you get the feel for it you can not so much touch down as settle onto the runway. A couple of times I could swear that I could feel the gear legs spread as the airplane settled with no noticeable contact with the runway. It was even difficult to pick out the touchdown on the video camera mounted in the airplane.

I also found that with a little effort I can hold the nose wheel off the runway until I'm down to about 20-25 knots. After 2 years, 220 hours, and over 300 landings the nose wheel still looked brand new.
 
I'm sure this will start a controversy, but I have never liked full stall landings in anything but a three point tail wheel landing. My reasoning has always been it's better to still be flying when you touchdown in case Mother Nature hits you with a gust. I'm not talking cruise, just Vs plus 5 Kts or so.

Let the storm of criticism begin! :)
 
Dgamble said:
A few things I've noticed after three flights and a dozen landings:

- Fairly deep drop of the right wing in stalls. After the first one, I concentrated on keeping the ball centered but it still drops the right wing.
Click to expand...

It could be a number of things.
Everything from not actually being in co-ordniated flight to miss rigged flapperons.

Dgamble said:
- I'm making full-stall landings, which may or may not be the cause of this: I'm pretty much thumping the nose wheel down on landings. Is this a technique thing? Roll it on instead of stalling it on?
Click to expand...

As already mentioned, there is no reason that the nose wheel has to thump down unless you are releasing back pressure as soon as the mains touch, or you are holding it very nose high during the roll out and then letting it fall on its own when you run out of up elevator. I hold it off until I am almost out of elevator, then let it down softly.


Dgamble said:
- It takes a lot of nose down trim for level flight, more than seems would be normal. I ran the threaded pushrod on the trim arm (the one that attaches to the stab) in as far as it will go, which seems to be the limit of available adjustment.
Click to expand...

Just because the cruise trim position isn't near the half way point, doesn't mean it takes a lot of nose down trim. Most of the trim range is intended to be in the nose up direction from this point, so that there is enough nose up trim in a slow power off glide.

Dgamble said:
I'm going to try letting the mains touch pre-stall later today, if the weather cooperates. Landing in a stall kinda implies that there's not a whole lot of lift (well, any at all) left in the wing, but I thought there might be enough left in the stab to keep the nose up. Stall speed is soooo slow, though, that maybe that simply isn't the case.
Click to expand...

Actual, in a stall the wing is still producing quite a bit of lift. just not enough to fully counteract the weight of the airplane. If this wasn't the case, the moment an airplane stalled it's airspeed (relates to fwd movement) would go to zero and the airplane would be falling vertically (which we know doesn't happen).
I think the issue is just that you are very new to the airplane. An RV-12 is very easy to fly (It is the easiest airplane I have ever flown), but it is different than most any airplane most people have flown.
If you are fully stalling and are still 6 inches above the runway surface, you will have an abrupt arrival which can then result in the nose wheel dropping hard (see below about seating position to help your view in the flair).
I bet once you get the sight picture better memorized, your landings will get much better. Speaking of that, sitting height can have a large influence. If you are not already, I suggest you adjust your seating position so that you are sitting as high in the seat as possible, with no more than a couple inches of head clearance, maximum. It makes a big difference.
 
Mains Only.

Hi,

If you did the type of landing you describe in one of the other A types you would be risking a flip over accident. I regard it as bad technique to put down any nose gear aircraft on all three wheels and even in very short landings there is no need to do it.

The landings shown in the Teen flight video is what you should be aiming for.... now that guy is good in my book.

The only the thing I mention as being a weak point on RV A types is the nose gear and teach everyone to land on the mains and keep the nose off as long as possible and let it settle gently. The 9A can easily be landed in 100 to 150 feet on a hard surface like this.

I totally agree about the ball, it may well be off, put a yaw string temporarily and practice keeping that straight until you are confident the wings are level and the aircraft not yawed on approach.

Best of luck with this.
 
rvbuilder2002 said:
As already mentioned, there is no reason that the nose wheel has to thump down unless you are releasing back pressure as soon as the mains touch, or you are holding it very nose high during the roll out and then letting it fall on its own when you run out of up elevator. I hold it off until I am almost out of elevator, then let it down softly.
Click to expand...
I think this may be part of it - a landing technique from more than 200 hours in the RV-6 (a plane that doesn't like a lot of left over energy in the wing and benefits from a little down pressure after touch down) may be carrying over. I made another eight landings yesterday and it worked out much better to adopt a nice slightly nose high attitude and hold that while letting the plane settle to the runway. No more thump, except in one case when I think I may have had a little brake pressure applied when the mains touched. That came from not yet being 100% comfortable with a non-steerable nose wheel - I was making sure I had my feet positioned to allow good braking. Having now determined that there is plenty of rudder available, that doesn't happen anymore.

Good to know about the trim. I seem to have all that I need in flight - it just seemed odd to be so close to an endpoint.
 
Is it possible to scrape the tail doing a true full-stall landing in the -12?

I guess it depends on the setup of the airplane, but I know for a fact that you can scrape the tail of the -6A doing solo full-stall landings, no baggage, power off, w/ full flaps.
 
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