Slip with full flaps in a B model

[DaveF]

Today I climbed to about 3000 agl and tried the infamous slip with full flaps. Sure enough, after a few seconds of slip, the nose dropped, though it was not close to being full nose down. I think it would have been a lot more exciting at 500 agl. Holding the slip, airplane seemed to fly itself out of the nose-down condition, but then it repeated. I've never experienced anything like that before.

[Zreyn]

I have heard stories (unverified) of 170B's giong inverted under the above described conditions.Wonder if anyone has first hand experience?

[Bruce Fenstermacher]

As written before this blanking and stalling of the tail surface with a slip and full flaps is controllable when it is expected. What I'm saying is it takes very little adjustment to unblank and unstall the tail surface and gain control. THIS IS NOT TO SAY I recommend this procedure, I don't. Even knowledgeable pilots are living on the extreme edge doing this on a normal approach. And a mistake will likely be a BIG mistake.

I've never heard of a 170 going inverted. I suppose in extreme cases of nose down attitude the fuselage could go slightly inverted and of course anything that drastic is probably going to feel like inverted to the pilot.

Dave it sounds like you experienced about the normal amount of nose down and recovery expected at approach speeds. It would likely be less at the upper ranges of flap speed and worse at the lower range near main wing stall.

[DaveF]

... Dave it sounds like you experienced about the normal amount of nose down and recovery expected at approach speeds. It would likely be less at the upper ranges of flap speed and worse at the lower range near main wing stall.

Yes, exactly. It was worse at low airspeed. At 3000 agl it was a fun ride, but inverted or not, at 500 agl it would have ruined my day!

[cessna170bdriver]

I got my initiation to this characteristic at about 300 feet. I'm sure it didn't go vertical, but sure felt like it due to the abruptness and the element of surprise. Thank goodness, when I coordinated the controls it recovered almost as fast as it happened.

Miles

[blueldr]

It happened to me right after I first got my airplane. I was on short final coming in to Cameron Park Airport in CA. I saw that I was a little high and decided to add a slip to get the numbers. A coupe of seconds later and I wouldn't be telling about it. I recovered about thirty feet AGL. Scared the living ---- out of me.
I had no idea what caused it until I read the POH later, instead of sooner. You know the old, bold pilots adage, "As a last resort, read the instructions."

[4-Shipp]

I tried this exercise myself a few years ago. Not only did the nose drop as advertised, but while still holding the full slip, full forward and aft elevator had little if any effect. the stab truly seems to be blanked out. I agree, not very scary at altitude. I don't plan on trying it down low. Cheers.

Bruce

[Bruce Fenstermacher]

When I first started flying as a passenger in a 170 a good friend and fellow flying buddy of mine use to demonstrate how he could just blank out the elevator and it would go limp. He could move the yoke in and out full travel with no effect on the attitude of the airplane. Just as the nose would start to drop he would take out just enough slip to regain control. I don't know if he ever considered what would happen if the nose did drop and we were low. I didn't know any better at the time. While most of the demonstrations were at altitude I'm sorry to say they all weren't. I've since educated him.

[GAHorn]

... I've since educated him.

What...you taught him to READ? I didn't realize you were also an English teacher.

[hilltop170]

Thanks for these posts guys. This is the most complete list of verifications of the slipping problem I have ever seen put together. I was actually wondering if the problem really existed since the other re-counts came one at a time and I didn't know if the pilot might have compounded the problem with a normal stall, cross-control situation, or some other non-standard practice which just happened to cause the nose to drop. I'm now convinced. Since I do not have access to a B model, I have never been able to try it out for myself.

I guess one could argue that the A model might have the advantage in the stall catagory since full flaps has absolutely no effect on slipping the airplane other than to create more drag. Heck, I have even spun the A model several times with full flaps just to see what would happen and nothing unusual does. And with the stock motor it will still land shorter than it will take off. With a higher HP motor, the big flaps do make a difference on take-off performance, no argument.

Do you B model guys ever really have the need to slip with full flaps? In the C-180/185, I have never needed to slip with full flaps. Just slow down and they will bring the plane down right now.

[jrenwick]

....Do you B model guys ever really have the need to slip with full flaps? In the C-180/185, I have never needed to slip with full flaps. Just slow down and they will bring the plane down right now.

No. It's just as you described with the 180.

The problem is with people who slip on approach out of habit. I knew a Tri-pacer pilot many years ago who killed himself landing a Breezy that he was ferrying for another purchaser. Breezys can't slip; they just slide into the ground. Jodel is another one -- they spin if slipped hard.

John

[GAHorn]

...A model.... with the stock motor it will still land shorter than it will take off. ....

ALL the 170's will land shorter than they will takeoff.

[markeg1964]

I happen to have been out a few weeks ago and decided to take a video out the front of my 170A. While landing I did a slip and got a video of it. Not too exciting but kind of fun. Jump to the 3:00 point in the video to avoid watching me fly the pattern.

http://www.youtube.com/user/markgunniso ... 0kU95pUppo

[hilltop170]

...A model.... with the stock motor it will still land shorter than it will take off. ....

ALL the 170's will land shorter than they will takeoff.

ALL the 170's with stock motors will land shorter than they will takeoff. Not so with extra horsepower.

Yes, the point being, more flap will not improve performance with the stock motor. Therefore, the A model with a stock motor is once and for all the preferred (safest) model due to not having the dive-when-slipping-with-full-flap safety concern.

I'm sure opinions may vary.

[Harold Holiman]

I agree with George and others that ALL 170's (and 180's) can be landed shorter than takeoff, regardless of the engine. I never had any problem with full flap slips in my 180. My 180 had the larger 185 vertical tail. My 180 was a light 53 model and was capable of a short takeoff, but, I could bring it in hanging on the prop and land VERY short, much shorter than a normal short field takeoff or landing. Same was true of my 170.

Harold H