There's a straight tail 172 with a 180hp engine and the tail wheel conversion which might be coming up for sale on my field.

Off hand I'm leery of tail wheel conversions, but I thought I'd see if anyone around here has flown one.

ravi wrote:There's a straight tail 172 with a 180hp engine and the tail wheel conversion which might be coming up for sale on my field.

Off hand I'm leery of tail wheel conversions, but I thought I'd see if anyone around here has flown one.

Ravi...

I have a '56 C172 with the Bolen conversion, and the stock O-300. Very pretty airplane, flys nice, but the problem is in the tail. The geometry is wrong, and as was discussed in a forum a few weeks ago, the fixed horizontal stab doesn't give enough elevator authority to flare while using full flaps. The C180 fixed that problem with the trimable stabilizer. Makes a huge difference.

Gump

GumpAir wrote: The C180 fixed that problem with the trimable stabilizer.
Gump

The 180 came out with that stabilizer a few years before the 172 went into production. Cessna obviously knew how great it worked cus they used it on the 182 through the 1961 model year. The 62 was the first to use the trim tab and that is when the nose heavy reputaion was given to the 182. A big step backwards.

My 182 B has the trimable stabilizer and what a soft touch it has. When trimmed at low speed you just have to tickle the elevator a touch to get a responce.

The 180's and 185's used this tell the end of production.

Tim

qmdv wrote:My 182 B has the trimable stabilizer and what a soft touch it has. When trimmed at low speed you just have to tickle the elevator a touch to get a responce.

The 180's and 185's used this tell the end of production.

Tim

That trimable tail is one of the main reasons why the C180 is an absolute joy to fly.

The C172 conversion like mine is not. It's tail heavy on take-off roll, and then on landing if you pull more than 20 on the flaps you can't 3-point well. But, with 20 you can land a whole lot shorter than you can get out of (with the O-300, don't know about the O-360 conversions).

Other than that, it's a nice little airplane. Real docile on the ground, wheel lands nice with no nose-over feel like the C120/140 gives if you push hard, and is pretty much well behaved like any other C172.

Gump

If you like the 170B you'll really like a 172 taildragger. They are the same except the larger tail on the 172 sq. tail adds more rudder authority.
I do agree the tail on a 180 is better but the 170/172 is a fine plane for the lower cost.

The geometry is wrong, and as was discussed in a forum a few weeks ago, the fixed horizontal stab doesn't give enough elevator authority to flare while using full flaps. The C180 fixed that problem with the trimable stabilizer. Makes a huge difference.

Maybe I'm comparing apples to pineapples, but since the 170 also lacks the trimable stabilizer, does it have the same issues? If not, what do you think the difference is...the geometry of the main landing gear or the actual tail surface?

ravi wrote:Maybe I'm comparing apples to pineapples, but since the 170 also lacks the trimable stabilizer, does it have the same issues? If not, what do you think the difference is...the geometry of the main landing gear or the actual tail surface?

I don't know. I'm not a C170 guy. Think I have about 5 hours in one, and that was over 30 years ago. In the C172TW, I'm assuming it's in the change from tri-gear stance to tail down in the conventional. The thing'll wheel land all day long with full flaps, and flys beautifuly, but try and pull it back to a full stall to three-point it with flaps out over 20 degrees, and you run out of ooomph in the elevator. The fixed stab might be a few degrees different in the C170-B's. But that's just a guess.

Gump

Haven't flown the straight tail 172. But I recently sold my 66 172 tailwheel with the 180 and constant speed prop. Awesome performance and very economical. Crosswind landings anything over 12knots would be almost impossible. But I believe the straight tail would do slightly better in that aspect. After too many trips from Maine to Florida with too many fuel stops I decided to sell when I found my 180. That 172 will make someone a great airplane for someone that doesn't want to pay the fuel, insurance, maintenance costs on a skywagon. I sometimes wish I kept that airplane, especially after I pay $300 at the pump to feed that O-520.

but try and pull it back to a full stall to three-point it with flaps out over 20 degrees, and you run out of ooomph in the elevator

I wonder if VG's would improve the elevator ooomph the same way they improve rudder authority on a twin?

ravi wrote:

but try and pull it back to a full stall to three-point it with flaps out over 20 degrees, and you run out of ooomph in the elevator

I wonder if VG's would improve the elevator ooomph the same way they improve rudder authority on a twin?

I thought Gump was describing my Maule, that is exactly how it handles. The VG's on the horizontal of the Maule help, but it's adding just a little bit of power at the bottom during rotation that does the trick. I'm not trying to turn this into a Maule discussion, but the handling sounds so similar, maybe the same trick would work.

a64pilot wrote:The VG's on the horizontal of the Maule help, but it's adding just a little bit of power at the bottom during rotation that does the trick. I'm not trying to turn this into a Maule discussion, but the handling sounds so similar, maybe the same trick would work.

It doesn't make much difference. I'll slow it way down in ground effect with a couple fingers worth of throttle, but it's an angle of the tail issue, and it won't pull down, and stalls with the tail high up in the air.

But, real world it's not really an issue, as with 20 degrees of flaps it will get you in and stopped anywhere you'd ever be able to fly the thing out of.

Got to ride in the converted 172 yesterday...I see what you mean about not being able to three point land, though with Jen in the front seat and me in the back seat it wasn't too difficult. Seems like packing my usual paranoid assortment of survival gear in the very back of the plane would be a possible remedy.

The plane clearly lacked the land-on-a-cracker short field ability that Jeremy demonstrated in his M-7, but the take off performance was quite good. The engine/prop combo seems about right to me...plenty of power if kept light.

Any chance the 170 has a few more degree of up elevator available than the 172?

It seems like loading to a more rearward CG might otherwise be just enough. I know it's like comparing apples and bacon but my Cardinal RG was a way better flying plane when loaded aft.

If you absolutely, positively need more up elevator authority roll full nose Down trim and you'll get it.

Gump

The straight tail 172 with a 180 hp engine makes a very nice, capable airplane. The issue that Gump describes is real, but as he says, it's manageable.

One thing to consider, is that the O 360 engine is thirstier than the O 300, and the earlier 172 s, like the 170 don't have much gas. So, depending on your mission, you may need more fuel....there are mods, but not cheap.

Other than that, These are great airplanes in many ways.

MTV

aftCG wrote:
It seems like loading to a more rearward CG might otherwise be just enough.

I'm fairly sure that better and more aggressive CG management will deliver good results. You might have to make up different tool kits (and emergency survival rations and water jugs and ammunition and a box of extra fishing weights) for several different aircraft loading, configuration, and fuel loads.

Of course none of this is as good as having a trim-able tail. No argument. People who have flown these airplanes for a living for years and years are in unanimous agreement about that.

But cutting your fuel burn by a big chunk in the age of $6/gal + avgas, if your typical mission does not require the full capabilities of the Cessna 18X, is also a very worthwhile benefit. The bottom line is that there is a market and a use for 4 cylinder, 6 cylinder, 8 cylinder, and now 10 cylinder cars and trucks. Some guys really need that 8MPG F-350 Dually. Some guys need a V-6 SUV that gets 25MPG. A lot of guys drive those F-350's back and forth to their kids' day care and almost never use that full hauling/towing capacity.

Match the airplane to your actual needs for at least 75% of the time you fly, and you will be in the "sweet spot" IMHO.

I was interested in this conversion some years ago and in my research I seem to remember that the tailplane incidence is slightly diferent between the 170 and 172 but never have verified this. If so it might explain the landing characteristics described here.
To counter this, the C170C prototype,which was certified but never released, was converted to a 172 and sold according the Bill Thompson's book

.Hamish

ZK Kiwi wrote:...the C170C prototype,which was certified but never released, was converted to a 172 and sold according the Bill Thompson's book.

Is that the 170 that was rumored to have a jack screw? I know that sounds crazy, but I have a friend who insists there were a few produced near the end of the run.

From what I know from Bill Thompson's book and also an article by Harry Clements in airfactsjournal.com , the C170C had basically C172 tail feathers with a trim tab.
PS Thanks again for the oil cooler, I haven't goteen around to pressure testing it yet.

Hamish Ross

Below are some extracts:

The original Cessna 172 was basically a 170C with a nose wheel instead of a tailwheel.


In the early 1950s, the sales of the predecessor Model 170 were perking along nicely, but two competitors made available for sale modifications that introduced a novelty that was getting some attention–a fixed tricycle gear. One was by an actual airplane modification company that even did it on our own airplane, the 170, offering a (I think certificated) version with that different type of gear. Our Chief of Flight Test got to fly it, liked the ease of landing but in general was ambivalent about the mod.



So Cessna management wanted to get an assessment of replacing a tail wheel with a nose gear on a modestly performing, fixed gear airplane like the 170. They acquired a Tri-Pacer and our group leader selected a team, pilot and observer, to conduct a mostly subjective evaluation of it. I was the lucky observer who was picked for the job.





.






Still the company was not yet committed and we had proceeded with the next model change to the continuing 170 line, the 170 C. The main change to it was to replace the old elliptical-shaped tail surfaces with modern, more efficient straight ones, like we already had on the 180. And their design was a task I was given, to be done along with the myriad other projects we had going at that time. It was not a technical challenge and sort of slipped my mind, but as a reward it got me the opportunity to fly some of the tests of the 170C prototype, which we went so far as to certificate.


The Cessna 170 was dropped soon after the introduction of the fast-selling 172.

And then the sales of the 170B begin to slip. Quickly, and secretly, work on a tri-gear version began, using the 170C as a foundation, with the main effort being to design the nose gear and its installation in the airframe. About this time I transferred to Cessna’s Military Airplane Division to work on the T-37, and the next thing I knew was that the tri-gear version of the 170 was introduced, and was called the 172. And its sales were so good that the 170 line was essentially discontinued and any concern of the Tri-Pacer as a serious competitor discounted.




.

Then many years later I read in a book that I had designed the empennage on the initial 172, the only major change to the 170 other than the nose gear. I thought the author was mistaken, because I had no recollection of doing that. I did concede that I might have forgotten it in the swirl of other activities we undertook at that time. But the author knew more than me, because the 170C airplane was translated wholesale to become the 172, with the exception of the substitution of the nose gear. And I had designed the new empennage for the 170C, so in effect also for the 172.

That I had once, and now again, forgotten about designing the 170C’s new tail was yet another disconcerting thought of mine related to the 172. It served mainly as an admission to myself that the tail design probably wasn’t such a wonderful technical breakthrough. And recognition that, more importantly, the long term record sales of the 172 was a truly unusual business success.
Harry Clements
Air Fact Journal

Considering the much higher cost of a jackscrew vs a simple trim tab, I doubt Cessna would have switched to one on a 170 unless there was a burning need. You'll recall that they switched from the jackscrew trimmable stabilizer to a trim tab on the elevator with the C182. The 180/185 had the jackscrew until the bitter end.