170A vs 170B

[jcraver]

I am looking for a 170 and have read the previous posts regarding the merits of 170's 17 A's and 170B's. Is there a notable difference in handling between the early wing and the later models?

Thanks
John

[N1277D]

Its been my experience that the 170B is more stable in turbulence, is slightly slower and uses more gas. With the larger flaps on the B model you should not slip it. The B can land shorter than the A model over a 50 foot obsticle. The B models also have other refinenements not found on the A model like a better heating system and a defroster on some later models.

[zero.one.victor]

Common wisdom is that the "straight 170" or ragwing model (1948) is the lightest,the A model (1949-1951) is the fastest,and the B model (1952-1956) the best at STOL (short takeoff and landing) operations. The truth,in my opinion,is that all airplanes are individuals. Some ragwings are heavy,some A's are slow,some B's are fast (but not your's,George--right Joe?),and STOL capability is as much dependent on the pilot's abilities as the airplanes. I've been told by people that ragwings are the sweetest handling due to light ailerons,but by others that the B's are the nicest handling due to the counterbalanced elevator.
I started out looking for a B,preferably a 1952 model cuz I prefer the early (48-52) cowl and panel. The best value I found was a ragwing,which I bought to fly til I found a good deal on a B. That was 5-1/2 years,a major overhaul,and about 900 hours ago! I still like the B's,but have grown pretty attached to the old ragwing so I'll probably stick with her.
You might do well not to be too stuck on a particular model of the 170,just look for a good solid airplane and buy the best value you find,ragwing A or B. Remember that it's easy (but expensive!) to overhaul a funky engine but not so easy to overhaul a funky airframe.

Eric

[6886]

First I'll say there by design is no bad 170 - the're all at the top of the list of the 4-place classics in my book. That being said, I've flown the range and I've owned 2 B's. Speed varies more between individual aircraft than between types. It's creature comforts that make the B my choice: balanced elevator, a good heater and defroster, the stability of more dihedrayl, and the comfort of big semi-fowler flaps on short strips. And don't think that you "can't" slip a B with flaps extended. You just need to be aware of how much flap and how much slip. In crosswinds I use a moderate foward slip with 20 degrees of flap. An aggressive slip with full flaps would be asking for trouble since the tail airflow may be disrupted at higher angles of attack. I agree with previous posters that getting a good 170 is more important than which model, but I always wait for the right B.

[funseventy]

The B was always my choice because I wanted metal wings, dihedral, and fowler flaps. Those are my desires but I agree with Eric that all are swwet airplanes. I can get jealous of Erics 50 Gallons of fuel when I'm sitting at 42. A models tend to be faster because of no dihedral, and thats what makes the B better in Turbulance. Eric, there was some piece of history published here on the 170 site a while back that said, "Surprisingly when they went to the metal wings of the "A" they saved weight over the ragwing." But now 50 years later I don't think that means much, since airplanes are like people in that some gain more over 50 years than others. You can make any of them have nice ailerons by lowering the cable tension. If you plan on doing short field operations, I'd recommendlight ailerons because it helps telegraph the "ready to go" information you're waiting on. There's a 170A on Barnstormers for 28K, that would be worth looking at. Its not a pretty paint job, but it is a 170 for under 30K. And these days that alone makes it worth looking at.
Kelly

[russfarris]

Sorry guys, I'm not buying the idea that a couple of degrees of dihedral would make the B model slower than the A, at least by any amount you can measure.

The simple piano hinge flaps probably seal better than the barn doors of the B. The less leakage, the less drag-inducing turbulence. But even then, I think we're dealing with only a few knots, at most.

My humble opnion...Russ Farris

[funseventy]

I agree that at the worst case we are talking a couple of knots. I would rather burn an extra gallon/hr than to admit that an "A" was faster. But from an engineering standpoint dihedral=slower.

Kelly

[N1277D]

A couple of years ago or so we flew my A model and a friend flew his B up to the Yukon. The A model was slightly faster and used slightly less gas than the B. Both were equiped the same - 800 x 6 tires, and roughly the same weight. The fuel difference was two or three gallons over 250 to 300 mile legs. The A burning 7 to 7.5 gph and the B 7.5 to 8 gph.

[russfarris]

Hey guys, I'm not disputing the A models are a little faster than the Bs; that seems to be the common experience. I'm just not convinced that it has anything to do with a couple degrees of dihedral.

I took quite a few aeronautical engineering courses at Embry-Riddle in the late 1970s, before I finally took the easy way out and changed my major to journalism. So I probably don't know what I'm talking about, but I don't remember anything about dihedral contributing to induced drag, especially in the very small amounts we are talking about here. In many years of designing R/C models (the only practical result of studying aerospace engineering!) and having many textbooks on the subject, it's news to me!

My gut feeling is it has more to do with the cleaner design of the retracted flap of the A. The flap gap seals sold to clean up the intersection of the retracted flap/wing area on the B is evidence of this. Not only is this an area of turbulence, but lower pressure air below the wing bleeds through the gap, creating addtional turbulence on top of the flap. Even though this is well behind the laminar flow, it is still drag. That is why high-performance aircraft generally have flap and aileron gap seals, among other reasons.

I'll keep looking in my old textbooks, but if someone can produce written evidence dihedral (again, small amounts, not 10 or 12 degrees) produces drag, I'd like to see it. Maybe I'll even look up one of my old professors!
Russ Farris

[russfarris]

On the subject of slipping with flaps, on the B you can do a full forward slip safely with flaps 20. The restriction only applies to full flaps. Conservatively, I don't slip with flaps 30. Russ Farris

[N170BP]

I've read where you're not supposed to, but I occasionally slip
with full (40) flaps in my B model. I initially experimented with
this at altitude in a '53 I flew for awhile years ago.

Maybe I shouldn't be doing it (I'm still relatively new to the 170),
but the "burble" in pitch authority/effectiveness seems very manageable
as long as you know it's there/coming if you push her too hard.

In my humble opinion, you'd have to be asleep at the wheel in order
to get into "serious trouble" slipping with full flaps in the B model.
Of course, I welcome the opinions of others with more experience.

All that being said, if I planned my approaches right all the time, I
wouldn't ever need to slip with flaps 40..... <grins>

Bela P. Havasreti
'54 C-170B N170BP

[Roesbery]

You are correct

[doug8082a]

Regarding the A vs. B speed: one thing I think may have been lost in the shuffle here is that the "B" has an additional twist in the wing (3deg. I think, but not sure). I'm no aeronautical engineer, but it seems to me that the twist would put more surface area into the wind and slow it down a bit.

[zero.one.victor]

Speaking as a ragwing owner jealous of those barndoor flaps--if you B-model guys need to slip even with 40 degrees of flaps available,you musta really made a p***-poor approach! It's pretty hard to make a good landing after a poor approach--just take it around & do a better job on the approach next time!
Regarding full-flap slips in a B,there's been a couple articles (in the 170 Book and in the 170 news) about people who did have the tail blanked out by the flaps slipping to lose altitude on the turn from base to final. Sounds like some upholstery-cleaning was required afterward in both cases! At least one of the pilots had done full-flap slips before with no apparent problem,but in this case there was just the right (wrong) combination of factors--gusts,wind shear,crosswind,or whatever-- to make the airplane pitch SEVERELY nose down due to loss of elevator authority. Not something I'd want to deal with when I'm low and slow!
" Discretion is the better part of valor"--one of my favorite quotes for aviating.

Eric

[Dave Clark]

I have a suggestion for those B drivers who wish to slip with full flaps. Get real high and pull full flaps and jam in a good slip. Then bank the airplane a bit and get a little slow. You'll be on your back in a jiffy flash! Do this once at a safe altitude and I'm betting you'll shy away from it forever. It's VERY quick and extreme. Remember the safest thing is to just go around and try again if you're messed up on approach.