Can a B Model be slipped at a less than 40 degree?

A place to relax and discuss flying topics.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Can a B Model be slipped at a less than 40 degree?

Post by GAHorn »

I would not recommend slip/spin/flight-testing a 60 year old airplane in order to discover an elusive, unpredictable response to a stressful maneuver without a jettisonable-door and parachute...especially only for the purpose to re-discover or re-document what is already known by the factory.

Texas A&M, Purdue, and other universities and agencies have wind tunnels which can demonstrate this much easier, cheaper, safer with a model anyway.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
TFA170
Posts: 132
Joined: Tue Jan 26, 2016 3:18 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by TFA170 »

gahorn wrote:Highly opinonated comments follow:
We all have strong opinions! :D :D
gahorn wrote:Slips were used on flap-less airplanes to lose altitude quickly during an approach which required a steep angle that did not accommodate flap-less aircraft. Once it's advantages were discovered ..even on ordinary arrivals to adequate runways which approaches the pilot had not properly executed ...those pilots employed slips to "save" their poor approach planning.

Flaps were developed as a significant improvement to airframes/flight capabilities. Slips were added to flap-equipped airplanes by those pilots who still couldn't plan/execute an approach.

Either use flaps. Or use a slip. Don't combine the two.
My 'highly opinionated' opinion is you're confusing tactics with capabilities...the tactic is rapidly losing altitude and flap-equipped aircraft, like the C170B have two ways (capabilities) to do it.

Slips are an aerodynamic capability of almost all aircraft, regardless of whether or not they are equipped with flaps. Flaps are simply a way to change the chord and camber, and thus the lift profile, of a wing...regardless of how an aircraft behaves when slipped.

Consequently, there is both a capability on the design side and the simple aerodynamic side. Aircraft behavior during specific maneuvers is independent of capability and really only goes to best practices...or unwise practices. To illustrate my point, for example, just because a Mooney is placarded against intentional spins doesn't invalidate the aerodynamic principles that govern spins. The spin is an aerodynamic principle/phenomenon that occurs under specific conditions - the Mooney will spin (and recover), but the recovery requires multiple turns and due to the 'clean' airframe, results in excessive speed during recovery and the potential to over-G the aircraft or exceed Vne. Consequently, it is placarded against such maneuvers because of behavior due to specific design characteristics based on compromises elsewhere.

While I have no placard, my '53 Owners Manual says, "Slips with full flaps are to be avoided..." - that doesn't seem to be much of a warning. And I concede that prior to that, it states: "The flaps on the 170 allow steep, well controlled approaches making slips unnecessary." - which I assume weighs heavily on your reading based on your "highly opinionated" position. :D :D

But knowing one's plane is imperative. I would actually recommend practicing slips with full flaps AT ALTITUDE to understand how your aircraft behaves. I believe it is imperative to know where the corners of your envelope are and explore them in a safe environment, when possible. And this is not so you can max perform your aircraft on every maneuver, rather, for those (hopefully) rare times that circumstances, environment, or self-induced buffoonery conspire against you and put you in a corner you'd rather hope not to be in otherwise...but have the ability to recognize and operate safely out of.

There is much to be said for stabilized approaches. There is equally much to be said for knowing how to safely fly your aircraft steeper than normal, and equally, shallower than normal. You never want to find yourself in an unfamiliar position if you can avoid it...I avoid 'learning' when it 'counts' as much as I can.

gahorn wrote:I would not recommend slip/spin/flight-testing a 60 year old airplane in order to discover an elusive, unpredictable response to a stressful maneuver without a jettisonable-door and parachute...especially only for the purpose to re-discover or re-document what is already known by the factory.
While I can fully endorse your intention here, I respectfully disagree that we have enough data from the factory. A mild caution recommending against something without explaining the severity is not as black and white as we'd like. I think it's far more important to know your aircraft under all operating circumstances to the maximum practical possible level. I am not endorsing full-on flight testing, but equally I'd never suggest flying an aircraft I was afraid of, or thought would be damaged (or worse) doing normal maneuvers...if you're that scared of the structural integrity of your 60-year old aircraft, perhaps it should be parked...and while I am by no means a metallurgist, I fully understand fatigue and necessary vs unnecessary stresses on an aircraft (which isn't always as black and white as we'd like it to be either).

The engineers design an aircraft that will be structurally guaranteed so long as it stays within a certain envelope. The factory write manuals that create an ellipse that lives wholly inside the rectangular box the engineers designed. Normal limitations and other rules/practices create yet a smaller ellipse concentrically within that larger manual-derived ellipse...the challenge is you may find yourself outside of the comfort of that smallest ellipse, and perhaps out near a corner of the larger box...that's not the time to learn something new. Know it before you find yourself there and plan to avoid that by all means, but be prepared for the unexpected.

For me, that means flying 3-5 good solid predictable patterns to landings with well-stabilized approaches. I then go out and do different things - I pull power earlier and leave it there and try to ensure I know how to make it to my intended point of landing. Or, I stay high on purpose to ensure I know how best to put my plane exactly where I need it to be. If you can "fix" the "unfixable" nothing will every catch you out. If you only fly vanilla, there's no guarantee you can get yourself out of a jam when you back is against the wall.

I'm in no way suggesting everyone immediately go out and become test pilots, rather, to incrementally challenge themselves to become better by increasing their skill set and filling their 'bag of tricks' with more tools and options based on their experience and comfort level.

YMMV.

*//donning flame retardant suit//* :lol:
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by Bruce Fenstermacher »

Very well written TFA. Much better that the response I had written and deleted in response to George.

George has good points. But it seems the "high opinion" he's holding on to is blocking his ability to develop further thought process beyond the box. Sometimes it's just plane fun to do stuff. Just do it safely.

I'm going to be thinking of George every time my approach leaves that stable approach path. Of course being a helicopter pilot I have a added advantage, no matter what, I rarely consider I'm not on a stabile approach. :wink:
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
ghostflyer
Posts: 1390
Joined: Mon Apr 21, 2008 3:06 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by ghostflyer »

We are all assuming that all our aircraft are the same after 60 years . None of them are and flight charactics change due to mods and repairs and general wear and tear and rigging . Plus the fact is not all us pilots have the same amount of training and ability to get a aircraft out of trouble in one of these tight flight coffin corners . I am shocked at the lack of knowledge a lot of owners have when unusual flight situations have occurred and haven't a clue how to bring the aircraft back to normal flight . The A of A indicator is the flavour of the month and a number of clients want one fitted . [ Must be the pretty led lights ]The client is taken up when we calibrate the instrument this is to show what happens to the instrument and the aircraft . I have seen many a white knuckle and the statement " do we have to do this " or " is this really necessary".
For example in a FULL power stall [clean aircraft] how many people pull back on power before lowering the nose . I am NOT a flight instructor but seen this a number of times . :( so if it's all necessary I do not put myself and my aircraft in a coffin corner on purpose . I fly the Cessna way as Mr Cessna would have it.

Edit.. reading back through the comments I noted that some one said the Cessna engineers design a aircraft around some know envelope and its structurely safe . NOT true. We can't assume its structurely safe if we push the edges of that envelope. I was test flying a Cessna 172 that had new ailerons fitted and some leading edge replacement. So I induced a power off stall. . , hands were off and working the rudders. Before I knew it I was on my back flat. Long story short , many rivets were popped on the main spar on both main planes. .
User avatar
TFA170
Posts: 132
Joined: Tue Jan 26, 2016 3:18 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by TFA170 »

ghostflyer wrote:We are all assuming that all our aircraft are the same after 60 years . None of them are and flight charactics change due to mods and repairs and general wear and tear and rigging . Plus the fact is not all us pilots have the same amount of training and ability to get a aircraft out of trouble in one of these tight flight coffin corners .
I agree with your basic statement, but approach it differently - I certainly did not claim all aircraft were the same, nor they were exactly as they left the factory. Regardless of state of aircraft (modification wise), it is incumbent on each pilot to learn as much as he/she can about his/her aircraft...preferably not all at once and certainly not when it's needed. It is precisely because none of us have the exact same training and experience that training should be incremental and within ones' comfort zone in a safe manner.
ghostflyer wrote:The A of A indicator is the flavour of the month and a number of clients want one fitted . [ Must be the pretty led lights ]
The AoA is indeed gaining some popularity and visibility, however, I think it is too little too late. Pilots are taught the book answer of when a wing stalls,yet go out and are trained to fly speeds. This is incongruous. An AoA gauge (calibrated to your aircraft) is indispensable and an outstanding tool when used correctly.

ghostflyer wrote:Edit.. reading back through the comments I noted that some one said the Cessna engineers design a aircraft around some know envelope and its structurely safe . NOT true. We can't assume its structurely safe if we push the edges of that envelope. I was test flying a Cessna 172 that had new ailerons fitted and some leading edge replacement. So I induced a power off stall. . , hands were off and working the rudders. Before I knew it I was on my back flat. Long story short , many rivets were popped on the main spar on both main planes. .
So, you're saying the aircraft in question was not as it left the Cessna plant? If so, then all bets are off and whomever designed the leading edge or did the work on the new ailerons is now the 'design engineer' and ultimately responsible for the airworthiness of the aircraft...

If you were referring to my comments regarding basic aircraft design, please re-read; they were general. Engineers design to certain limits and/or percentages of limits and this creates a box (not necessarily square or rectangular) bounded on the sides by stall and structural integrity. Within this 'box', the manufacturer creates a flight manual whose limits and recommendations reside wholly within the engineered box. This is further scaled down by common practices, rules, and other guidance....my point was merely that the time to find out just what the aircraft is capable of is not when you suddenly find yourself out in one of the far corners, but, rather, well before that through training and familiarization.
User avatar
Ryan Smith
Posts: 1210
Joined: Tue Nov 25, 2008 4:26 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by Ryan Smith »

No, it's cool.

I love insurance hikes. Please, everyone go nuts.
User avatar
ghostflyer
Posts: 1390
Joined: Mon Apr 21, 2008 3:06 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by ghostflyer »

The 172 that had the new ailerons fitted and leading edges were standard parts from the factory . The original ailerons had too much corrosion in them and the leading edge section was replaced because the aircraft rolled into a tree .park brake /wheel chocks not applied .
Maybe I should have included that in the text but was trying to keep it short and simple.
User avatar
Bruce Fenstermacher
Posts: 10313
Joined: Tue Apr 23, 2002 11:24 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by Bruce Fenstermacher »

Ryan Smith wrote:No, it's cool.

I love insurance hikes. Please, everyone go nuts.
Was that "No" a B model shouldn't be slipped at less than 40° flaps if It's cool someplace?

You like hikes with insurance?

Everyone should be a nut?

I'm not following you Ryan.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: Can a B Model be slipped at a less than 40 degree?

Post by GAHorn »

Well, I'm disappointed in both responses from Richard (TFA) and Bruce.

The implications in those responses that I am "afraid" to fly my airplane is both incorrect and insulting. The suggestion that it's a good idea, even at altitude, to perform flight-testing experiments to explore a maneuver the factory specifically warns against in this airplane model is incautious at best and irresponsible at least.

My previous "opinionated" post was intended neither to express a personal fear of flight testing or fear of this airplane. My intention was to instill a healthy respect for the fact that:
1-Almost none of these airplanes are any longer in the pristine condition of a factory-fresh airplane, and those that are.... are not likely the airplanes whose owners reading these forums are likely to use when following the suggestions given to go to altitude and see what experiments one can create "ad hoc" in some misguided pursuit of "improving" one's techniques in the airport pattern. My own Oshkosh-winning airplane is no longer anywhere near it's factory-fresh weight and balance condition. I cannot even think of suggesting someone who's airplane has never even been weighed since the 1950's go out and take it to the edge of it's flying envelope, regardless of the altitude selected. W&B is only ONE consideration that does not meet the conditions the factory test pilots met when they discovered the hazardous operation in this discussion.

2- Flight testing is not something the average private pilot* who owns these airplanes is qualified to be doing, especially involving potentially dangerous maneuvers. As an employed production test pilot I have participated in flight-testing of many, factory fresh airplanes for a major airframe manufacturer and I have also flight-tested airplanes just out of major modification centers and I can assure you the comparison between those operations and the ad hoc "go up and see" suggestions made in the above posts border on foolhardy, ... and will serve no purpose in most cases anyway. Longtime, experienced owners of these airplanes have told tales of having performed these slips with flaps extended many times...and never experienced any problem whatsoever...., until ONE DAY 8O and THEN when they were least expecting they were made believers! The impromptu flight testing I imagine most readers of these forums may undertake have no relation to the hazards to be tempted, in most cases nothing strange will occur...and the owner will decide no hazard exists... and one day a possible tragedy may happen.... and what possible benefit accrued?

3-This Association should not be encouraging owners to go out in their airplanes and attempt maneuvers which are specifically cautioned against. We have lost at least one, fine Member and his wife and their lovely, fully-restored 170B ...why? ... Because of ignorance of the hazards of this maneuver. Instead of encouraging Members and participants in the Forums to go out and violate the guidance of the maker of this airplane... we should be encouraging compliance with those cautions! To do otherwise is irresponsible.

This airplane received it's airworthiness certificate under rules/regulations which, at the time, closely followed a light-plane development period in which simple airplanes with predictable flight characteristics were commonly flown by pilots who were well-aware of and proficient with the simple capabilities of those airframes. The rules/regulations of both airplanes and pilots of the period were not what we have today. Spins were required of every private pilot applicant. Often the applicant was required to be capable of recovery from spins in designated turns and headings! As late at the 1970's this was no longer the case. If fact, in the 1970's only CFI applicants were required to be taught spins ...and they were never actually required to demonstrate recovery in any practical test. Often the FAA inspector or his designee themselves were afraid of spins!... and that practical test was likely being performed in an airplane which met the latest certification requirements that demonstrated the AIRPLANE would RECOVER on it's OWN within a turn-and-a-half if the pilot simply LET GO of it!
This airplane, if newly designed and built today, would not simply have a gently worded sentence buried in the SALES DEPARTMENT PUBLICATION which never met any airworthiness authority approval. It would have a prohibition prominently placarded accompanied by liability disclaimers. (BTW... with regard to the comment suggesting that "engineers" of this airplane have somehow protected us with the strength of their design....how many readers have recall that this airplane is designed for 4.4G's positive, and 1.76 Gs negative? And how many of you recall that the negative G's designed for in this airplane with FLAPS DEPLOYED are... ZERO!
Now, consider again for a moment of that negative flight attitude which may occur as your old airplane slams nose-down and possibly upside-down with those flaps deployed and your rudder shoved over to the side in the slip you tried while following some folks suggestions.)

And THAT was my intention in making my "opinionated" post above.


* As a flight instructor of almost a half-century's experience I can attest to even highly qualified commercial and ATP rated pilots who lack the skillset to adequately recover from an inverted spin without damaging a new airplane, much less a 60 yr old airframe. While I do not believe that it takes a CFI certificate to have a valid opinion on flying "tactics" or "capabilities", I do not believe either of the two suggestive opinions above are responsible. As a certificated graduate of the Gene Soucy Aerobatic schools advanced course, I believe If forum participants wish to gain experience in flying on the "edge" , I highly recommend good aerobatics courses conducted by experienced aerobatic instructors in aerobatic-certified airplanes... not 60 year old designs that should be placarded with a prohibition against the maneuver.

PS: The reason the Mooney is placarded against spins is because it cannot meet the spin-recovery requirements of either CAR3 OR FAR23... it is a low wing, has some of the smallest flaps in the industry, and that airplane's flight characteristics have little to do with the 170B situation.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
c170b53
Posts: 2527
Joined: Mon Apr 22, 2002 8:01 pm

Re: Can a B Model be slipped at a less than 40 degree?

Post by c170b53 »

I'm not disappointed in any of the replies to this post, but I think the opinions of George are more to my thinking. I consider myself as a marginal pilot, have no fear of spinning planes but I shudder at the thought of spinning my plane. Sometimes flying over the hills, the heavy bumps make me wonder how tight the joints are.
Again I appreciate everyone's responses here, it's a risky business, stuff does happen.
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
n3833v
Posts: 857
Joined: Tue Apr 23, 2002 6:02 pm

Re: Can a B Model be slipped at a less than 40 degree?

Post by n3833v »

This type of discussion is why I encourage anyone that owns an airplane to join that type club/association so that they receive the pertinent information on that plane for their safety. Then IF they want to experiment on their own, do it safely. I always want safe flying so we can encourage others to want to fly.

John
John Hess
Past President 2018-2021
President 2016-2018, TIC170A
Vice President 2014-2016, TIC170A
Director 2005-2014, TIC170A
N3833V Flying for Fun
'67 XLH 900 Harley Sportster
EAA Chapter 390 Pres since 2006
K3KNT
User avatar
170C
Posts: 3182
Joined: Tue May 06, 2003 11:59 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by 170C »

Justin's original question was, "Can a B model be slipped at less than 40 degree (s)? I think the simple answer is YES. A B model can be slipped at any flap setting, but it shouldn't be. You guys have given numerous reasons supporting your opinion/knowledge. That, as John said, is a good reason to belong to a type club. That same statement that is in the owners manual for the B model 170 also applies to the early 172's like mine. I used to slip mine with 30-40 degrees of flap deployment and never gave any thought to it. That was my mistake of not rereading my owners manual carefully :oops: I consider myself lucky to have never had a problem doing so, but it is likely due to my not doing a full slip or not doing so for any length of time. After we lost our 170 member and his wife to what we think was the result of slipping their B model with full flaps, I have ceased doing so and bring this to the attention of any of my friends that have Cessna's with large Fowler flaps. Yes, you can slip these planes, but best to do so with no flaps.
OLE POKEY
170C
Director:
2012-2018
User avatar
Ryan Smith
Posts: 1210
Joined: Tue Nov 25, 2008 4:26 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by Ryan Smith »

Bruce Fenstermacher wrote:
Ryan Smith wrote:No, it's cool.

I love insurance hikes. Please, everyone go nuts.
Was that "No" a B model shouldn't be slipped at less than 40° flaps if It's cool someplace?

You like hikes with insurance?

Everyone should be a nut?

I'm not following you Ryan.
No, I'm agreeing with George wholeheartedly on this.

When I teach students in my 170, I teach them "slips or flaps, never both". Having flown nearly 1000 hours in the past 12 months, I'm pretty well on top of my game with regard to currency and proficiency in GA aircraft. I want nothing more than to spin my airplane, but it's been over 20 years since she's been gone through and she just isn't as fresh as she used to be. I have plans to do a major refurbishment within the next five years, and even then, I don't intend to go spin the airplane after she's been cleaned up and had major invasive inspection and component replacement.

Having said that, I still have a lot to learn, and while I'm a stubborn person by nature, this is one of those things where I'll defer to other people's experience and not go poke the bear. Like Doug said - if your approach is that bad that it requires 40° flaps AND a slip, you need to go around or pick another place to land. Even in an engine-out scenario.

A friend and forum member here (who shall remain nameless) has done the slips with full flaps thing at altitude with several 170Bs, and all responded similarly. He was wearing a parachute at the time, and has remarked that he wouldn't do it again. There is enough documented proof out there that this should not be touched on.

Now, I realize that the question was related to slipping with less than 40° flaps. Another member on here, whom I greatly respect, has brought up the point that there may be rigging differences between the airplanes that contribute to this. I feel that this is a valid point, and this further reinforces my "slip OR flaps" MO that I drive home with students.

Furthermore, I find it a bit poor in taste that members/representatives of the club are fostering this discussion further than "don't do it, dumbass". I would not be averse to the Association doing a documentary a GoPro inside the airplane as well as several external angles to demonstrate the outcome, as well as dissect the aerodynamics and offer other points of note and caution. Absent of that video being produced, I feel that the Association should take the stand of "slips with full flaps in a B model can be hazardous to your health" and move on.

I have 18 assassins at any given time that I fly with, and as such, it takes a lot to get me uncomfortable in an airplane, but this makes my skin crawl. I won't let anyone fly my airplane that thinks this is okay, and I'm subject to not get in their airplane with them for the same reasons.
Watkinsnv
Posts: 187
Joined: Tue Apr 23, 2002 1:55 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by Watkinsnv »

Now on cross wind landings wing low opposite rudder up to 30 degrees of rudder. Technically a slip. How many people use this technique. On a calm day or light winds I always use 40 degrees of flaps. I never crab into the wind and try to kick it out like a tricycle gear aircraft. I think its normal to us flaps on landing. I haven't heard a response to cross winds and use of flaps. except some say they like to make wheel landings others full stall landings and get the tail wheel down. I think a crab approach leaves you to greater chance of large loads put on the main gear and ground looping. But the approach is what I'd like to hear more of please.
User avatar
Ryan Smith
Posts: 1210
Joined: Tue Nov 25, 2008 4:26 am

Re: Can a B Model be slipped at a less than 40 degree?

Post by Ryan Smith »

Watkinsnv wrote:Now on cross wind landings wing low opposite rudder up to 30 degrees of rudder. Technically a slip. How many people use this technique. On a calm day or light winds I always use 40 degrees of flaps. I never crab into the wind and try to kick it out like a tricycle gear aircraft. I think its normal to us flaps on landing. I haven't heard a response to cross winds and use of flaps. except some say they like to make wheel landings others full stall landings and get the tail wheel down. I think a crab approach leaves you to greater chance of large loads put on the main gear and ground looping. But the approach is what I'd like to hear more of please.
If it's windy enough that I need to wheel the airplane on, then it's windy enough that I don't need flaps. YMMV
Post Reply