Backcountry Pilot • Cessna 170A v.s. 170B

Cessna 170A v.s. 170B

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Re: Cessna 170A v.s. 170B

There really is no need to slip the B with 40 degrees as the decent rate at super slow speeds is astonishing. Pretty fun actually.
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Re: Cessna 170A v.s. 170B

Does Cessna allow an A model to be modified to a B model? For example Luscombe allows an 8A to be modified to an 8F, or whatever model in between, by simply changing the engine to a C90 and adding whatever else was required on the basic 8F. Then in the eyes of the FAA the plane is an 8F.
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Re: Cessna 170A v.s. 170B

whee wrote:Does Cessna allow an A model to be modified to a B model? For example Luscombe allows an 8A to be modified to an 8F, or whatever model in between, by simply changing the engine to a C90 and adding whatever else was required on the basic 8F. Then in the eyes of the FAA the plane is an 8F.


In short, no. Wings are different. Buy a B in the first place.

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Re: Cessna 170A v.s. 170B

On my first CFI ride, in 1976 I think, the Inspector wanted me to do a forward slip to a landing with full flaps--it was a late 60s 172 with 40 flaps available--and up to that time, I'd been told that it was "prohibited" and had never done one. He told me to read the placard on the door post--and it said "not recommended". Prohibited is one thing, not recommended is another. I learned then exactly what it did, and it causes a mild phugoid bobbling at appropriate approach speeds and a more pronounced bobbling at higher approach speeds. Close to the ground, it could be disconcerting. But there's no loss of control.

Since then I've done many full flap, full rudder forward slips in many different Cessnas. The ones with a longer dorsal fin tend not to be affected as much as those with no or very short dorsal fins. But it's not a big deal in any of them. The previous owner of mine (63 P172D) installed the longer dorsal fin, and I get no bobbling at all.

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Re: Cessna 170A v.s. 170B

On my first CFI ride, in 1976 I think, the Inspector wanted me to do a forward slip to a landing with full flaps--it was a late 60s 172 with 40 flaps available--and up to that time, I'd been told that it was "prohibited" and had never done one. He told me to read the placard on the door post--and it said "not recommended". Prohibited is one thing, not recommended is another. I learned then exactly what it did, and it causes a mild phugoid bobbling at appropriate approach speeds and a more pronounced bobbling at higher approach speeds. Close to the ground, it could be disconcerting. But there's no loss of control.

Since then I've done many full flap, full rudder forward slips in many different Cessnas. The ones with a longer dorsal fin tend not to be affected as much as those with no or very short dorsal fins. But it's not a big deal in any of them. The previous owner of mine (63 P172D) installed the longer dorsal fin, and I get no bobbling at all.

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Re: Cessna 170A v.s. 170B

The 170A has a pilot's manual empty weight of 1220 lbs which is impressively light, although most weigh in 100lbs heavier+ . I am not sure how Cessna showed that weight - no gyros, no engine accessories (starter, gen, etc), no rear bench, no paint?

What does a B model typically weigh in at?

Given the EW of typical 180/185 types, a lightly loaded 170 should have a pretty good take off performance. Two up, two hours avgas, a light 170 is weighing similar to a PA-18-150?
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Re: Cessna 170A v.s. 170B

Any empty weights given in ANY aircraft manuals are absurdly low. As you noted, those are typically done with no "options". Like tires, instruments, radios, electrical systems, etc...... :roll: In short, those are a waste of paper, and anyone who relies on them is bound to be disappointed.

My B with O-360 and MT prop weighs 1336. I've flown Cubs that weighed more than that, and most Huskys nowadays are in that range.

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Re: Cessna 170A v.s. 170B

mtv many thanks, makes my early Super Cub's EW of under 900lbs look quite good.

I am impressed by your 0-360 equipped 170 weighing in at 1336 lbs, which is lighter than my neighbour's stock 170A. With modern avionics and materials there is no reason why this type can't edge closer to sub 1300lbs.

Very few C-170s in Europe, and they command a premium in terms of price.

Am not sure why the Husky has gone the other way, as a new build weighing much more than a CarbonCub, or a 170?
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Re: Cessna 170A v.s. 170B

The A model has 50 degrees of flap available where the B model has 40 degrees. The A model flaps extend further out the wing than the B model. I dont know what the surface area comparison is but I think it is quite similar. The full flap stall speeds for both models are identical. Therefore I believe it is a myth that the B model is a better short field machine. There is one advantage to the B and that is the heater and defrost. I fly my A model at 10F and above. It is a bit chilly. Dont underestimate the 170 especially one like MTVs with a 180hp. I have a light weight starter, alternator, battery and back seat removed. At Johnson Creek this year friends with supercubs both took off prior to me giving the first one a good five minute start. I was at 9000 feet an easy five to ten minutes before them on two seperate occasions. Could have been my ability to find the updraft though. B models have dihedral in the wing which improves stability in turbulence but may carry some disadvantage in a cross wind landing as compared to the level wing on the A model. I believe there is little advantage from one to the other. Put a 180hp in it and you've got an amazing airplane.
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Re: Cessna 170A v.s. 170B

Re: Cessna 170A v.s. 170B Quote Zzz
"I never experienced it, mostly because I was spooked by the tales I read here of people slipping with full flaps and blanking out the tail, causing a sudden and severe pitching down."

Careful there!! I had that plane do it to me once. I was by myself, and in a slip then yanked on full flaps. ( don't ask what I was doing). It pitched down quite sharply, which I promptly remedied by dumping the flaps back to 30. If it had been electric flaps might not have been so good.
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Re: Cessna 170A v.s. 170B

If the 170A flaps have a longer span, shorter chord, does that mean the 170B has an advantage with aileron control at slow speeds, as presumably it has larger ailerons.

Does not necessarily follow as you might have more risk of aileron reversal at low speed? Although the B wing with dihedral may also have some washout? In any event Cessna must have been happy with the evolution to the B wing as they used it in the 172.
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Re: Cessna 170A v.s. 170B

It's not only the span and chord of the Cessna Para Lift flaps that makes the difference. The B flaps are semi Fowler flaps, whereas the A model flaps are simple hinged flaps. The advantage has little to do with surface area, though I suspect the B flaps are still larger in surface area. Frankly, I believe that the bigger difference in use of flaps is on takeoff, as opposed to landing. 20 degrees on takeoff gets you up and running quick.

But, frankly, the nut behind the yoke probably makes more difference than the flaps in many cases. Learn to fly it well, and the A will do just fine in most cases.

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Re: Cessna 170A v.s. 170B

I have a '48 C170 Ragwing I have owned 25 years. Just a stock airplane. Yes different than a 170A or 170B. I use the flaps on most all landings. Has stock engine, well a O-300-A, not the C-145, but same hp. Some good points are, lots of room, comfortable, good amount of room with back seat removed. Flight caracteristics of the rag wing are different that the metal wing of the C170A or C170B. The ragwing is light, and not much wing loading, so wind or turbulance not much fun. A buddy that had a metalized ragwing flew better in wind or turbulance. in the 1950's Hutchinson had a kit to metalize the ragwing. Some were done nice, others look butchered. His was nicely done. Most add additional fuel cell on the left, yes same as the C140 12.5 gallon. Standard config is one on the left, two on the right wing. With the advent of all the lightweight, batteries Odyssey, starters, alternators, seats, etc, I plan on changing out to loose some weight and make the airplane light as possible. But these planes are not what I would consider short take-off, they do allright, but need more horsepower. The old 6 cyl motors are smooth, and econimical. The '48 didn't have the option of a STC for bigger engine like the C170A or C170B does such as the 180hp Lyc O-360. But I am hearing that cracks are starting to show up in stringers around the engine mount firewall bulkheads?
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