Entering the 170 market

[GAHorn]

Re: the elevator counterbalance wts are a simple matter to add the maximum wts allowed by the control surface balance limit charts: A models have no bal. wts. B models maximum elevator balance wts are: .92 lbs for the 170B Right elevator and .75 for the left. Total is 1.67 (less than 1 3/4 lbs actually.)

Actual Empty weights of aircraft are not found in the Owners Manual (produced by the marketing dept) but in the equipment list and/or most recent wt balance of the individual aircraft. I don't doubt the typical A model left the factory lighter than the typical B model, because the B model had more standard equipment, better and more interior appointments, and typically more and better radios. None of this is valid 50 years later,...today....when all these airplanes have changed equipment and likely gained/lost weight like the rest of us.
"That difference jives w/ my experience"... I'll bet you base that statement upon the wt and bal sheets you've seen on aircraft you are personally familiar with......aircraft that are unlikely to have a current/accurate wt and bal ....because if you go out to the ramp, get into any 170, the odds are very high the aircraft has an obsolete wt and bal. sheet dated a long time ago. Hardly a condition to confirm any statment that "B-models are 50 lbs heavier than A models." At this stage in any 170's life, it's weight is a very individual situation, IMHO. My B model has only very basic radios, only 1 com, txdr, nav, encoder, all of which are lightweight digitals. I"ve seen A's that have dual KX 170B's (or worse considering weight, older MK 12's etc, with indicators, AND seperate, heavy power supplies mounted in the tail, ...and ADF, sometimes an old King 8000 series loran or something equally heavy, etc.
Now don't get me wrong. I'm not being critical of fellow 170 owner's radio packages. I'm only pointing out that my B model happens to have radios that weigh only about 12 lbs, and my interior is a complete removal/replacement, while I've observed lots of A and B models that have interiors covering older interiors and radio packages that weigh 25 or 30 lbs or more. My opinion is, no statement made these days can categorically be made with regard to whether A models or B models weigh more or less than the other.

You are correct regarding the flaps/slipping. (I made an unfortunate choice of words when I said "prohibiiton'.)
Legally, Slipping with full flaps in a B model is "advised" against. (But I stand by the intent of my comment: Be aware that slipping a full flap B model can give you a surprise when it rather suddently points itself straight downward and trys to roll into a spin. Remember that a crosswind involves some degree of slipping, and that full flaps in a strong crosswind is not a good technique in most any airplane, and can be especially tricky if full flaps are used during crosswind landings in a 170B model.)

RE: follow on models of aircraft....
The 172 is a different model aircraft with a different type certificate. It is technically not a 170 variant.

RE: the stall warning: If you read the type certificate you'll see near the end of each models description a listing of "required equipment". Item 607, stall warning, is only required on the B model. It is "eligible' (not disqualifying) on all models...but is only required equipment on the B.
I've not made it a habit to inspect all A models for stall warning installation, ...I only meant to comment on it's required status on a B model. (This is possibly a good A model argument. A failed stall warning is technically a no go item on a B model.) (Shut up, Joe!)

[blueldr]

Paul,
You must be getting the greatest fuel mileage I've ever heard of in any kind of a Cessna 170. !08 mph on less than 6 gph! Fantastic! And with a seaplane prop too! Double fantastic!!

However, if you have doubt about the "KILLER" pitch down in a full rudder slip with full flaps in "B" model, I caution you, sincerely, not to try it without LOTS of altitude. If you try it on short final, you will be dead, and will ruin a great airplane.

Square tailed Cessnas don't do not have this problem to anywhere near tiis extent.

I learned about this characteristic of the B mobel the hard way.
Fortunately, I had just barely enough altitude to avoid total disaster, except for my shorts. It was one of those deals where you " read the instructions as a last resort".

[N4588C]

Paul,
I disagree to a point with your assumption that should avoid and not allowed are different. Go the the NTSB accident reports page and I think you will see the words "failed to avoid" peppered through out there reports.

I am new to the 170's, so I'm learning a lot as I read in the different areas of the association. I fairly recently purchased a 1953 170B. Flys great!! Getting ready to rebuild the engine though. It was mentioned earlier that as important as low time is, equally important is the manufacture date. I knew the engine was not going to go to TBO but was hoping for 200-300 hours. Managed only about 150.

Welcome aboard John. A C170 is a great airplane. If you ever want floats, gotta be a B.

Happy Thanksgiving to all and safe flying.

Bob

[N170BP]

Personally, I fail to see what all the excitement is about slipping
a B with full flaps.... Yeah, if you push her too far, you get
oscillations in pitch. Big deal.... You'd have to be asleep at
the wheel to let her bite you that way....

There is plenty of warning before the pitch excursions, and
even if you come across same, all you have to do is back
off in the slightest amount (basically let go of the controls),
and she regains her composure pronto.

Bela P. Havasreti
'54 C-170B N170BP

[spiro]

geez, didn't mean to stir it up so much!

George,
my comments on the weight differences are based on actual weighings not obsolete w&b paper. Like I've already admitted, how a particular airframe is outfitted makes alot more difference than the model.

on the stall warning being required only on the B, I "get" it now, never noticed that before. But I do find it curious that it's not req'd when on floats...

blueldr,
don't think I ever implied that slipping w/ full flaps was a good idea, just that Cessna (&/or the FAA/CAA) didn't think it was necessary to placard prohibiting it.

I did say iirc (if I remember correctly) 108mph on under 6gph. Looking at my records for the last couple years it's more like 102mph on 5.8gph with that prop. That's usually light, always aggressively leaned, low density altitudes, about ½ the time on skis.

[170C]

George, is the reason the B models are required to have a stall warning device is because they are slower than the 170 & A models? (Wink)

[AR Dave]

My 55 stall warning is a red light located on the panel under the yoke shaft. Is that original?
Because of it's location I can't see it, but I know it works because my wife says it lights up all the time.

[GAHorn]

George, is the reason the B models are required to have a stall warning device is because they are slower than the 170 & A models? (Wink)

Ha! I expected that from Joe!
I didn't expect him to put his "hatchet man" on the job!

Seriously, I am only speculating that the B model didn't give adequate aerodynamic warning prior to the stall like the 170's and 170A's do. The dihedral, wing wash-out, and slotted flaps all work together to get the airplane noticeably slower and therefore closer to the stall without much fussing, then the stall is ...right there!

AR.... the red light is also accompanied by a warning horn that is contained within the capsule. If your horn isn't blowing, let me know and I'll tell you a possible "outlaw" fix. (Those dang audible/visual warnings are expensive. Last I checked they ran about $600!)

All: I recommend you check those stall warnings during preflight inspections. Turn your master on, go out and lift the detector vane on the leading edge. You should hear a horn and someone should look to see if the lamp illuminates.
A very experienced pilot friend of mine (dum-dee-dum) once stalled on takeoff at a high, very dark, mountain resort takeoff due to a failed airspeed that showed rapidly increasing speed. The airport lights had just timed out, it was a dark hole, the cockpit only had red-glow overhead lights, there was no outside reference for pitch, and the seat of the pants said "this much speed increase right after lift-off can only mean I'm descending back down into the mountain" so "my friend" pitched up some more. The airspeed still increased rapidly and so more up was added,...until the stall warning blared!
That told me,....er..I mean,..my friend!.....that something was lying and so the artificial horizon was used to pitch to only slightly above level flight attitude. The warning extinquished, the climb proceeded normally, and as the flight climbed up to 11,000 ft, the airspeed went off the high end of the scale. (The airspeed indicator behaved similar to an altimeter due to a failed/plugged pitot reference.) I'm convinced the only reason a hazardous failure didn't lead to a serious and possibly fatal accident was because that stall warning horn worked correctly.
Make certain that YOURS does,....regularly!

[N1478D]

George, is the reason the B models are required to have a stall warning device is because they are slower than the 170 & A models? (Wink)

Ha! I expected that from Joe!
I didn't expect him to put his "hatchet man" on the job!

Frank does my LIGHT (slow) fighting for me!

[blueldr]

Bela,
I don't have any idea what your airplane does in a full flap,Full slip, but my '52 does not give any pitch occillations at all. It just flat pitches over violently and everything loose in the back ends up on the glare shield. If you're close to mother earth, kiss (yourself)* goodbye!

[N170BP]

Mine doesn't do that (pitch over violently). I suppose if you
aggravated the situation (intentionally applied full crossed
controls with full flaps) it might get interesting.

My point is, the airframe lets you know right before it gets
unhappy. My opinion is it is a manageable trait, which is
why Cessna used the words they did (i.e., full flap are to be
avoided if possible, but they're not prohibited).

Bela P. Havasreti
'54 C-170B N170BP

[GAHorn]

The larger B model flaps produce a huge downwash that does not occur in the previous models. When that downwash reaches the horzontal stabilizer it causes a very large nose-up pitching moment that most pilots either overcome manually with down elevator...or they re-trim the airplane to a nose down position in order to relieve the strong stick-force required to prevent the aircraft from pitching up.
When the airplane is then put into a slip, the fuselage blanks out the downwind stabilizer and the nose-up force that half of the stabilizer has been providing is suddenly gone! The result is a sudden nose-down pitching moment that is uncontrollable as long as that stabilizer half is still blanked out. The applied rudder from the slip simultaneously puts the airplane into a turning/rolling moment resembling a spin.
If you are at low altitude, such as on short final, the flight attitude can be so far advanced that recovery can be impossible depending on altitude. It's my belief that Bela's comment is likely based upon his perception of normal slipping behavior. Whenever any of the models are slipped hard there is a continual pitching and bobbing going on that is to be expected....and that may be interpreted as the airplane "letting you know... it (is) unhappy". I personally don't believe those clues are a developing "unhappiness" symptom of impending pitch-down. I believe that is the ordinary disturbed uneasiness that occurs with all airplanes being slipped (rather than a unique trait of a B model about to pitch violently downward.) The B model acts just as uncomfortable in a slip as all other airplanes do and gives no additonal warning that it is about to suddenly fill your windshield with a view of the ground.
Since a slip is a cross-controlled condition, and since cross-controlling any airplane can lead to an accelerated stall and resultant undesired behavior,...I don't believe the B model was perceived as being sufficiently unique as to require a placard of any stronger warning than the one already installed to avoid slips with full flaps.
I once had a King-Air windshield crack in front of my first-officer in a pressurized airplane showering him with splinters of glass but otherwise remaining in place in it's frame. I asked him to leave the cockpit and sit in the seat immediately behind me and read thru the checklist to ascertain that we'd followed all the checklist items for the problem.
After we'd landed at the destination (which was only a few miles ahead when the ws failed) I called the home base to speak to the Dir. of Mx. I was amazed at his insistence that I simply wait for my pax to finish their business and fly the airplane back home with them unpressurized.
I pointed out to him that the flight manual stated "The windshield should be replaced before further flight." HE insisted that did not constitute a REQUIRED action, ...that "should" was only a recommendation. I refused to do it and made them send me another aircraft. I was in hot water with the boss until I whipped out the fax I'd gotten from Raytheon/Beechcraft that re-enforced my position stating that "SHALL" is the root-word of "should".
I'm intrigued at the concept that the word to "avoid" doesn't seem to carry as much importance to some. I expect that those who embraced that concept at low altitude and lost ... simply aren't around anymore to join the chorus to "avoid" full flap slips in a B model. I am convinced that "avoid" is a commanded action, not a requested one.

[N170BP]

I've played with my B (at altitude) in a slip with
full flaps at length, and right before it gets "unhappy",
the elevator feel goes from 90-100% effective to something
like 20-30% effective. It's at this point that any more cross
controlling (or a gust of wind) can make things interesting.

I'm not the greatest stick in the world (duh!). All I'm saying
is I can feel this reduction in elevator effectiveness in the
controls, and I know that pushing the slip any further will
make the view out of the windshield "interesting".

There is a certain amount of cross-controlling / slipping you
can do (with full flaps) with no-ill effects what-so-ever. Push
it past that point, and it's a different story.

I guess my thought is there are numerous "limits" defined
& published about the operation of our aircraft, and some of
these "limits" may be different for some people than others.
What about the demonstrated crosswind capability of the airplane?
Some can't handle such crosswinds, while others routinely land
in such winds without giving it further thought. Cessna suggests
an approach speed of 70mph with the B. With practice (and under the
right conditions), a 55mph approach speed will also work if the
situation requires it.

For the record, I do "avoid" slips with full flaps just as Cessna
suggests. I just disagree that the sky will fall if you do so. With
practice, one can learn just how far the slip / cross-controlling
can be pushed before the airplane becomes unhappy.

Bela P. Havasreti
'54 C-170B N170BP

[Bruce Fenstermacher]

Bela

I agree with you 100%.

As a full time helicopter pilot I almost always find myself high on approach cause of the different sight pictures of each aircraft. I do a lot of full flap slipping but I always do it very carefully.

I have always been able to feel the elevator get sloppy and correct with less rudder. Control to the elevator is instantly returned. I've never pushed it far enough to have the nose drop.

I'm sure someone not familiar with the characteristics of this maneuver in a B model could have bad things happen.

[Dave Clark]

All this about flaps and slips...my 2 cents, being as my friends know quite conservative, is that there are a lot of ways to kill yourself in an airplane. Some known, some unknown. The flap/slip in the B model is a known problem. Why in the world would someone want to flirt with it? Better yet why would we want to encourage it here on this forum? Yes I've messed with it up high and know if you're careful and not really aggressive you can keep it flying most of the time. But you only need to push it over the edge once down low and you'll probably never get a second chance.

One thing I know is that I won't be the one to do that. I'd rather do a missed approach.

Flame suit on.