C170A vs 170B

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C170A vs 170B

Postby hbcroft » Sun Jul 07, 2002 1:54 pm

Hi again

I am new the the world of cessna 170's and I am sure this question has been asked and answered many times before. What are the main differences between the C170A and C170B? I know an important one seems to be the straight wings (170a) configuration as oppose to some amount of dyhedral on the B models. Is this a big advantage? What is better for bush flying (skis, floats, etc)?

I live in the NWT and pretty much all the flying is over bush, snow, water and a lot of the landing strips are made of gravel. I am looking at alternatives to my Citabria and the more I look at the C170 the more I become interested however don't know much about them.

Any advice will be appreciated.

Cheers

Bruno
Ft Smith, NWT
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History of the Cessna 170

Postby gahorn » Sun Jul 07, 2002 4:57 pm

The History of the Cessna 170 (Gary Hanson doesn't need to read all this.)

Early in 1948, aviation publications across the country were publishing press releases similar to the following, which appeared in the February issue of FLYING magazine:

Wichita, Kansas - A full line of Cessnas will roll off the lines this year. Deliveries of the new 1948 model Cessna began early in January ... The big news in the way of completely new aircraft at Cessna this year is the Model 170, a four-place plane powered by a 145 hp Continental engine. Selling at $5,475, this new 170 is the low-cost four-placer to complete Cessna's full line. Deliveries are expected to begin in March ...

During the late 1940s through the mid-1950s over 5,000 Cessna 170s were manufactured and well over half that number survive today. This alone should indicate that this aircraft has certain qualities that make it a desirable aircraft to own and has also gained it recognition as a Neo-Classic in various aircraft organizations.

The Cessna 170 began its life looking much like its little brother, the Cessna 140. In fact, the 1948 C 170 is quite often mistaken for the smaller two-place C 140 by the casual observer. In 1948, Cessna expanded and stretched the 140 to make it a four-place aircraft and called it the 170. It had no dorsal fin, had fabric-covered wings, vee-type wing struts and three C140 fuel tanks to give it the necessary range for its larger engine. The engine used was a Continental C 145 (later designated the 0-3 OOA) and would be used throughout the entire production run of Cessna 170s.

The First Production Model

The first production model was scrialed #18001, but both it and #18002 were experimental and eventually scrapped by Cessna. The first C170 produced for sale to the public was SN18003, which rolled out of the factory doors on 6 February 1948. She made her first trip on 27 February. From Wichita, she made demonstrations for Cessna dealers across the United States .... Little Rock, Orlando, Miami, Birmingham, various cities in Texas, Salt Lake City, Boise, and on to Bozeman, Montana on 5 May 1948. She bore the numbers N2500V and was based in Montana until sold to a dealer in Calgary, Alberta in 1973. The plane was purchased by Mr. McNiven in that year, and he flew the plane approximately 75 hours until he was involved in a landing accident in 1976. The aircraft is rebuildable, but the owner feels that the plane (in it's current condition) is worth $7000 due to its historic significance.

Beginning very late in 1948 with SN18730, Cessna began producing the all-metal, slicked-up version which we recognize today as the 170 - single strut and with a dorsal fin identical to the one used on the C195. The price new was $5,995, and it was called the Model 170A. The plane had an all-metal wing with slightly larger flaps which ran from a 0 degrees setting full up to a full down setting of 50 degrees. The 170A, which was produced through 1951, is commonly called the 'straight wing' model because, unlike later 17OBs, the C170A has no wing dihedral. There were very few changes made in the C170A in its three years of production. The chief difference lies in the cowling. The 1949 model used the same fixed cowl flap on the cooling air outlet as the Ragwing. In 1950, the cowl flap and rear cowl opening were changed to the configuration used on all subsequent models. Incidently, the first production model of the C170A series, SN18730 N3843V, is still flying, and is featured later in this book with articles on rebuilding and updating of the Cessna 170 series in the Modifications Section, page 89.

Cessna Introduces The 170B ...

The Cessna 170B was introduced in 1952 and continued in production with several changes until production on the series ended in 1956. The most obvious change from the 170/170A is the large Semi-Fowler flaps similar to those used on the L-19. (Note: Actually the L-19 wing and the C170B wing are essentially the same except for military hardpoint/hardware.-gh)The flaps were labeled'Para-lift'by Cessna, but the term "bam door" is the more common description. The flaps originally had four settings: 0, 20, 30, and 40 degrees. Beginning in 1955, Cessna added a 10 degrees flap setting. The 10 degrees position is probably the favored setting for normal take-offs since there is a very slight pitch change with flap retraction compared to 20 degrees. Several owners have added the 10 degrees notch to their flap quadrants. (Note: This is an illegal modification, unless documented, submitted and subsequently approved on a FAA Form 337. Get approval before you do this to your airplane, and look for documentation if you purchase an airplane so altered.-gh)

The dihedral angle was increased to 3 degrees (Note: 2 degrees, 8 minutes actually-gh) on the 1952 and all subsequent models (the C170A wing was flat) (Note: See, Joe? Flyguy is right!), and more twist was given to the wing between the strut and the tip. The stabilizer and elevator shape was changed and the aerodynamic balance area was increased. A mass balance, enclosed in the aerodynamic balance section, was added, requiring less control pressure. The C170B elevator, when raised and released, simply floats to the down position, whereas a C17OA's falls with a bang.

In 1953, the engine cowling was changed from the center-hinged type with an internal air box to a full- pressure cowl. Cabin heating was also improved by replacing the single outlet with a manifold-type that runs across the firewall with outlets for both front seats, a windshield defroster, and ducts to the front doorposts for heat to the rear seats. The instrument panel was extensively reworked. The small T-shaped floating panel was replaced by a full-width floating panel indentical to the one on the C180. Piano key type switches were replaced with push/pull type and space was provided for side by side radio installation in front of the pilot. Overhead panel lighting was also introduced.

Until mid-1953, the C170 had spring steel landing gear legs that were interchangeable between right and left side of the aircraft. These are readily apparent by their thick ankles and outward bow. This system was changed in mid-1953 with SN25612 to the non-interchangeable right- and left-hand narrow-ankle stiff gear.

Changes in the 1954 C 170B were removal of the fuses from the lower instrument panel to a separate fuse panel below the panel on the left side, placement of the battery on the left side of the firewall, and the flush riveting of the wing struts at the lower end.

There were two major changes in 1955. The most obvious one is the shape of the rear window, as it was squared-off in the rear instead of being eliptical in shape. The other change was to the tail wheel steering by the use of a cable running through a pulley system to the tail wheel instead of the previously-used rudder hom spring system.

The Cessna 172 was introduced in 1956, and tricycle gear took over the general aviation scene. Since Cessna had parts left for some C170s, they continued to produce the C170B with a few changes. To keep costs down, the interiors were changed to the molded type like the C172, the access door (side window) on the right side was fixed in place instead of swinging out, and brakes and flight controls were made optional on the right side

Performance.

The stock Cessna 170 will pretty much do what the Owner's Manual says. It will get into a much shorter field than it will get out of at gross weight. It will cruise in comfort at about 118mph at 65% power at 4000'-7000' and burn about 8gph with engine properly leaned. Some people say a C170A is faster than a C170B due to less wing dihedral and flap drag, but it's really the individual airplane that makes the difference: how it is rigged, the number of antennas and other drag-inducing obstructions, overall condition, etc.

Most C170's will take two adults, two children, 100 pounds of baggage and full fuel (A and B models hold 42 gallons, 37 useable) and still be legal for a gross weight of 2200 pounds. The C170 will climb 500- 700fpm at this weight and land at about 52mph.

The Cessna 170 is a good, honest taildragger and has had very few AD notes or problems with maintenance.

There you have it, a picture of the Cessna

(This article was taken from "The 170 Book" available from The International Cessna 170 Association. It has been edited by me, but it's original author was Bob Baas of Irving, TX)- George Horn
Last edited by gahorn on Sun Jul 07, 2002 7:58 pm, edited 1 time in total.
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Postby N1478D » Sun Jul 07, 2002 7:20 pm

Neither the A or B wing is flat, the curve is what gives us our lift :P The A model has a STRAIGHT wing Gary and George. A Classic STRAIGHT wing I might add, it is a visual characteristic of the A crowd that is pleasing to the eye. Having spent a little time recently in a couple of B models, and over 500 hours in an A, the straight wing, flaps, and other improvements in the B would not be near as important as the general condition of the aircraft, i.e. corrosion, rigging, engine, avionics, etc. . Personally, I believe happiness could be had with any of the 170 series if the airplane was in good sound condition. The B model seems to be in more demand, so resale value might need to be considered. But as far as flying characteristics and comfort, my opinion is that they are almost identical.
Joe
51 C170A
Grand Prairie, TX
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Postby hbcroft » Sun Jul 07, 2002 8:20 pm

Thanks for your comments Joe. Would you or anyone else in the 170 world know how big/expensive of a job it is to install a float kit on either one of those models?

Thanks again

Cheers

Bruno
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Postby JDH » Sun Jul 07, 2002 8:50 pm

Hi Bruno,
if you are thinking of floats, short strips and bush, you should invest in a STOL kit. Price of a float kit depends on who installs it and what you consider a complete float kit: With V brace, fueling steps and handles and lifting rings or just the attach points. A couple of guys that got a "complete" float kits in the last couple of years spent $10 K (Canadian). But, unless you got the ponies up front, you are talking about a 2 seater that needs very tight, well rigged floats and long lakes/rivers... JD
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Postby hbcroft » Sun Jul 07, 2002 9:28 pm

Thanks JD

I read you on the type of performance to expect with a 0-300/145 cont. A 2 person float plane is fine by me. We are located right on the western edge of the Canadian shield so lots of lakes/take-off lenght is not usually a problem and elevation is usually no higher than 1500 asl.

I feel I need to learn more about the 170 but it appears to be a good alternative to my Citabria 7ECA. Will keep following this site as it is a great one and a good source of info.

Thanks again from the Canadian North...

Bruno
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Postby Roesbery » Mon Jul 08, 2002 2:33 am

Find a B model allready converted to Lycoming 180 Hp. Even if it has quite a bit of time on the engine, as long as it is in good shape. A lot less expensive than converting from scratch. Stol kit, long prop, big tires, a plus but you can add them as you are able. You will be able to get in and out of most any place the citabria can. Your speeds and such will be about the same except you will glide a lot farther in the 170B when you cut the power on approach and will have to allow for it. Watch out for planes that have been used hard as super cub substitutes and not maintained, unless the price is in a bracket you can live with while doing all the repairs needed. A lot of people are put off by poor paint and beat interior. but that makes opportunity for those willing to do the work themselves. A top notch A&P buddy can help a lot. Charlie
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