Charley Chicken as my dad calls it...our '54 170B. I bought it in late november, stuck it in my dad's hangar in oregon, and resumed the ski season with the intent to get checked out in it as soon as possible. Well, thanks to a great ski season and the inconvenience of having our new airplane located in Oregon while I am in Reno, I just didn't get around to flying it until yesterday(jmtgt thinks I am nuts.) Why not just keep it in Reno? Well, my dad owns a hangar in Grants Pass, and we have had ambitious plans to do a gear upgrade, as well as some avionics additions. It's nice to do that in a warm hangar without the rain or wind or UV rays beating down on you. Plus, he is my partner in the aircraft, so I imagine he'd like to fly it too.

On a brief ferry flight from Medford to Grants Pass shortly after the purchase, we noticed the notoriously smooth C-145 running rough at full juice. We did some measuring and noticed one prop blade out of track by about 3/16". Could that be the cause? The prop was pretty warbly as it has 1800+ hrs since recondition, so we sent it north to be overhauled and painted. A certain shop in WA who I won't name took their sweet time on it, to the tune of 3 months and $600.

When the prop got back to us, it looked really, really nice except for the huge ding in one blade. Back to the prop shop. I guess a thanks goes out to them for covering their work and getting it back inside of 2 weeks this time, but they need to work on their communication skills.


Over the weekend, Jr.CubBuilder flew his '52 170B down to Grants Pass for a visit, and we went for a short flight around the area. I forgot my camera on the ground, but I managed a few of him arriving and departing. We compared 170 notes, of which I don't have many yet, and basically talked ourselves into believing we have the greatest, cheapest, funnest airplanes available. That's the magic of type clubs I think. Jr made a rather impressive wheel landing, and that was all I could think about for the days following.

Back to wednesday... Reinstalled the prop, called down a friend who qualifies for the open pilot requirement on our insurance policy to act as PIC (he is just a great pilot all-around with plenty of tailwheel time and is an A&P to boot) and taxied down for takeoff. Left magcheck produced about a 200 rpm drop and considerable roughness, so I leaned it out quite a bit and ran it up, hoping to burn off whatever contaminants were causing the roughness. It finally smoothed out, so we took off. More on this later.

Not only have I not flown in months, but the majority of my time is in tricycles, and what tailwheel proficiency I had faded into the snow back around thanksgiving. First thing, I got bitched at for resting my whole foot on the rudder pedals, rather than heels on the ground, toes in the middle and not on the brakes. I proceeded to aggressively bring the tail too far up and do a stinkbug takeoff roll, which I got slapped for as well. I was already embarassed but who am I out to impress? I just don't want to bend my new-to-me airplane.


The first thing I noticed was that the throttle doesn't stop at the firewall. At full throttle, the shaft is still quite exposed, and that bothers me. Every time I glance at it I automatically reach up and push on it to make sure it's indeed fully opened. The next, and more disturbing thing I noticed was that we weren't making the 2700 rpm that the full 145 ponies fulfill their destiny at. We were more like 2475, and it was a loud 2475. Wap Wap Wap Wap, like a lawnmower or helo or....an engine seriously out of time? Was the prop still wacky? I have the MacCauley DM7653. 76" long, pitched to 53.

While I was not happy with that, it wasn't catastrophic so we did some maneuvering and slow flight to figure this 52 year old airplane out. I had made the mistake of flying with my friend in his 2004 Decathlon earlier that morning (he let me fly it a little.) How do you think it feels to transition from a brand new aircraft with aileron spades and lightning quick control response, to my old 170? I have to admit, it was a bit of a let down and I briefly had thoughts of being trapped in a fairly sizeable loan and how to get rid of it.

Our flight was around 2pm, and while the winds were light and variable, there was some thermal activity and it was a bit bumpy. At one point I got excited and all was magical again as I saw 1000+ fpm on the VSI, but it soon faded as we exited the thermal and continued on our warm day sluggish climb with full tanks and 400 lbs worth of pilots. I flailed a bit on the seemingly sluggish controls(those old 170 yokes are kinda ergonomically challenged), and had problems getting used to the instrument scan in this classic panel layout. I think anyone who has learned in a modern Cessna is used to the six-pack layout of instruments, but I had to reprogram my brain in the span of a few seconds to avoid further embarrassment. Then there's that dual scale ASI...should I read the mile per hour scale or the knots scale? I know the 172 kias reference speeds by heart. I tried that but the bigger numbers on the mph outer ring kept getting in the way!

Time for some slow flight practice and some imperical data collection for stall speeds at various flap settings. I reached down to grab 10 degrees flaps and soon realized the folly of cinching down the Aero Fabricators shoulder harnesses like an aerobatics wannabe. To avoid further embarrassment I simply leaned sideways a little and managed to stifle the pop of my shoulder dislocating as I made an attempt to get to that flap handle. DOH! Screw it, shoulder harnesses loosened and floppy.

After a while struggling with maintaining target airspeeds at various flap configs, and doing a really poor job of maintaining altitude, we decided it was time to run the gaunlet and just land the thing. Twice in a row, while attempting to make a position report on pattern entry, my cheesy push to talk button spun on the yoke, and I got as far as "Grants Pass traff..." and was forced to choke up on that button and call again.

Wow, a little high on final with 20 degrees out, but airspeed right on target 70 mph. I was going to grab 30 degrees but Dana advised against it and said to just hold it. The saying "slow down to go down" was running thru my head, and sure enough by slowing it down just a tad we touched down about 1/3 of the way down the runway on what could have easily been a REALLY long landing. It is a surprisingly easy aircraft to land, and I managed a decent 3 pointer with my standard creep to the left side of the runway, but got that in check right away. Moved my toes up so my whole foot was on the rudder pedals, and tried those brakes out...they're touchy.

When I first started this thread, I didn't intend to write an article or story of any kind, I just wanted to share my stoke. I have a really old airplane that is in really nice condition, but it runs a little rough. We're thinking plugs, timing, or even a mag in need of rebuild. We may have to repitch the prop a bit to make the full 2700 rpm, but this engine should run smoother than it does. I was not impressed with what everyone has been calling a very smooth engine(the C-145), so something must be up. It runs healthy on the ground, throttles up quickly, fire to life instantly on start, but once under load on climbout, it sounds lawnmowery with an anti-smooth staccato. I'm hoping it's just an ignition issue and it'll smooth out with new plugs.

Overall, the last week signals my return to aviation from a world where I daily prayed for bad weather and snowstorms to lay down a blankey of powder in the mountains. Now, bring on the high pressure and calm air, sunny days, and lower fuel prices. I realize most of you by now have lost complete respect for me as a pilot, so let me pound in the final nail with this photo. You can tell that I am stoked though.



Jr's bird:

You lucky dog! I'm envious.

You might want to consider a dynamic prop balance. I also had
a shakey prop on my airplane when I bought it. It balanced statically
just fine, but just "wasn't right" at rpm / in the air.

The way it was explained to me, a fixed pitch propeller can balance
statically just fine, i.e., one blade weighs the same as the other
after "schmoozing" (technical term) either blade to make the propeller
balance in the typical 1954-manufactured static balancer.

The problem is, after who-knows-how-many re-pitching excercises,
or prop straightening and profiling efforts from oppsie-daisies, one blade
may have it's center of gravity nearer the hub while the other has it's
center of gravity nearer the tip.

Also, when they re-pitch these things, they will only "average out" the
pitch for the two blades so that they are "equivalent". When in motion
however, one blade may have it's "center of thrust" at a different
point along the blade span as the other, and at cruise rpm, this
is definately noticable. Bottom line, chances are that after a re-pitch,
the thing will never run as smooth as a new prop which was manufactured
on a profile milling machine so that each blade is profiled exactly the
same way at the factory.

In any event, I chased prop balancing propblems for awhile (the logs
showed that I wasn't the first one who tried to "fix the problem" by
sending the prop to the shop for an overhaul / static balance), but
the only thing that fixed it was a dynamic balance with a Chadwick
balancer (best $179 or whatever it was I've ever spent on an airplane).

I have no affiliation what-so-ever (just a satisfied customer), but I
highly recommend Paul Nyenhuis at Aviation Inspection & Repair
at the Arlington airport. Paul spent 3+ hours with me, getting the
prop as close as he could to perfect. He did say mine was the "worst
fixed pitch prop he had ever come across" insofar as a dynamic balance
was concerned.... I forget what the weights were, but we were a few
grams from the machine "shutting itself down" and saying "something
is really wrong" before it would balance properly!

Now it runs turbine-smooth like a C-145 should.

Zane,

First, you should never actually see 2700 rpm on takeoff in an airplane with a fixed pitch prop. Actually, 2500 is about as good as it will get, depending on what type prop you have, and what pitch it is set at.

Even at level flight and max throttle setting, most fixed pitch airplanes won't quite get to red line, and that is as it should be.

So, don't worry much about that. If you had a constant speed prop, it should go to redline on takeoff, but not a fixed pitch.

You can have the prop re-pitched to a flatter pitch if you want a little more takeoff performance, and climb performance, but you'll lose cruise efficiency if you do that.

I'd check the plugs, and clean them, that's likely your roughness problem, and I'd definitely get the prop dynamically balanced on ANY airplane. It's well worth the cost.

Now, If you ever go to a prop shop and see how they pitch props, its a really crude process. So, it is entirely possible that they've got one blade pitched slightly different than the other. If it is really kind of rough, I'd send it back to the prop shop, or another, and get it right.

An O-300 (I haven't flown a 170 with an O-300, but I've operated them in Sedans, 172's, etc.) should be smooth as glass. They are very smooth engines normally.

So, I'd make dang sure the prop is right (and I'd suspect it's not right now), clean and gap the plugs, and when everything is about right, I'd have the prop/engine dynamically balanced.

MTV

Thanks for the ideas guys. The dynamic balancing is something I had not thought of. I'll let you know how it goes.

While you are at it.....I have found some engines with a replaced jug ran rough. I found that when a single jug has been replaced, sometimes the piston has been replaced with one of a different mass, which produces the resulting dynamic vibration. If it only happens in thin air, most times its a mag cross fire, or a plug well jump over (get the plugs with the double seal, wide well. Same price for the harness and the plugs). Valve clearance on some engines will produce a vibration due to the lift differences between cylinders (Solid lifters).

If it has lord mounts, check the condition and make sure there is no metal to metal contact at the mounts from bad hardware choices...or cracks.

Hey Zane,

Congrats, dude... I remember all those feelings, and although they brought me a crazy mix of elation and consternation, as well as a serving of humble pie; they are some of the most treasured flying memories I have. The cool thing is, I still get a hint of all those emotions when I push the throttle forward on Punkin... It never really goes away for me. Especially the humble pie.

Did you know that "Charley" was Jerri Mock's nickname for 1538C, the Cessna 180 (also known as the "Spirit of Columbus") that she flew solo around the world? She was the first woman to do it.

M

I guess I should mention that I'm at ~600 SMOH, all jugs replaced with Milleniums at overhaul time. Last significant motor repair was an exhaust valve grind on #5 cyl 2 years ago, so Zona I'm thinking I can rule out the black sheep piston. Interesting idea though.

I'm going to put new plugs in, test, then if that's not the simple answer, I'll start troubleshooting the plug leads, the mags, etc.

I'm leaning toward the dynamic balance issue though, especially from what Bela said.

punkin170b wrote:Did you know that "Charley" was Jerri Mock's nickname for 1538C, the Cessna 180 (also known as the "Spirit of Columbus") that she flew solo around the world? She was the first woman to do it.

In that case I guess I'll have to go with "Charley Jr."

Love them tailwheel airplanes- they sure keep you on your toes! I call mine "the Humiliator". It (or me!) is the reason they call landing practice "smash & dash","bounce & goes", or "bumps & circuits" (depending on what part of thew world you're in).

Eric

Zane,

Before you do anything drastic, have the prop unbolted and rotated 180 degrees and remounted. When remounting be sure to tighten the prop bolts to their recommended torque specs. Sometimes this can make a world of difference.

If you have deposits it can cause a little assymetric compression and vibration, people have used a little Marvels Mystery Oil to cure this.

If your turning 2500 RPM on takeoff you should be good on pitch.

On the other hand the problems you had with the prop shop may indicate other problems with their quality control.

you for got hit and runs; rudder rubber and feet, all the things that never stop bouncing; POed by PIO;

there are others, im just brain dead.

Dane