Adding 10 degrees flap setting to B model

[Exploreit2]

First off, YES, I realize that this was already brought up but that was two years ago.

I have a 1954 B model and I would really like to add the 10 degree flap setting notch to my flap handle.

DOES ANYBODY HAVE A 337, STC, ETC. THAT I CAN GET A COPY OF?

What are the steps it would take to make my 54 B have a 10 Degree flap setting?

Once again, any and all help is greatly APPRECIATED!!!!!!

[Bruce Fenstermacher]

....What are the steps it would take to make my 54 B have a 10 Degree flap setting?

A really nice file and some time

Seriously this is one of the "no brainer" mods that if presented right to the local FAA should on a 337 should get approved but of course under change15/16 probably won't.

I'd talk to your FAA FSDO and tell them that first the "mod" is approved for this aircraft after certian serial numbers. Explain to them that you already can and DO fly with 10 degrees of flaps buy holding the flap handle in this postion

Not sure if the part numbers for the old and new rachets are the same. If they're not them tell them your going to modify the old part to the new part specs including the extra notch.

Not sure if the flight manual, the single sheet not the Owners Manual specifies the 10 degrees but if it does tell them you'll use the newer flight manual other wise there shouldn't need to be any flight manual change.

Basically I've found that the Feds have no clue how smaller GA aircraft work. They can't invision what you want to do so they can't figure out that it is a simple modification. You need to give them a arm and fuzzy feeling about the modification.

You need to be armed with enough information to answer all of their questions. Basically, baffle them with BS. Pictures and drawings, a 337 filled out with Instructions For Continued Airworthiness are must. A PowerPiont presentation might be over the top.

Tell them it would be safer (they love saftey) to have the notch to hold the flaps for you rather than you holding the flap handle. If they don't feel good about the modification then the simple and safe answer for them is NO. They get paid either way.

Good Luck

[Roesbery]

If it is a '54' seems like it should have the 10 degree notch my '53' does. Maybe some parts were changed somewhere along the way? A drill and a file in the right place will fix it just fine.

[lowNslow]

The ratchet with the 10 degree setting is the superseded part for the old ratchet. It is fairly easy to replace and will cost you about $115 for the part. To just grind a new notch, while certainly easier done, would not be legal without some real 337 headaches.

[Exploreit2]

So there is no way I can add the notch to my current ratchet?

There isn't a part number stamped on the ratchet itself is there?

Wouldn't it just be a part number change in the books then?

[Bruce Fenstermacher]

If you could modify your old part to meet the standards of the new part under AC 20-62D, owner manufactured parts. In other words manufacture your own new part.

Install this new part which superceded the old and had licenced mechanic make a log book entry that the new part was installed. You might be OK.

What does your IA think?

I know we've discussed this kind of stuff here before but what does the brain trust here at the forum think?

[N170CT]

LowNSlow Karl,

Any info on where to obtain the part with the 10 degree notch??

My 56 "B" model will sometimes allow the flaps to retract just when I don't want them to and I suspect the rachet is worn.

Any info on locating the part and installation would be most appreciated.
Chuck

[lowNslow]

The rachet is available from most any Cessna parts dealer.

Http://www.iwantcessnaparts.com

Has them listed as "in stock" for $98 (part #0510171-1)

You might also need part #0705004-1 (supersedes #0510191) which is the flap handle placard for Ser #26050 and on which I believe came equiped with 10 flaps. Not sure what it says as mine is worn off. It cost a whopping $1.95.

The placard may not be required by the TC, I am not sure off hand.

[lowNslow]

Just looked at the 170 TC and it does not show that the flap handle placard is required, so you can save yourself $1.95.

Also noted an error in the TC. It says the following:

"Note: S/N 20267 through 26504 were delievered without the 20° Notch."

These S/N have the 20 degree, but NOT the 10 degree.

[zero.one.victor]

I'm curious why the desire for the 10' degree flap setting? For takeoff? How does 20 degrees work for takeoff,and how would 10 degrees improve things?
Or is it maybe for slow flight (not MCA,but loitering/observation flight--75 mph-ish)?
My ragwing has 4 notches of flaps-- the book sez 30 degrees which I assume would be 30 degrees. I measured them- the flaps deflect 35 degrees max. So I guess maybe someone modified them along the way.
I use half flaps for takeoff,and full flaps for landing. Works pretty good. Especially considering how small the flaps are. An A model has hnged flaps like a ragwing but they actuially have quite a bit more flap area,as well as deflecting to 50 degrees (according to the book).
I often use 1 or 2 notches flaps for loitering and observation flight,usually while orbiting at around 70 mph or so. Seems to increase control effectiveness and reduce the need for nose-high attitude.

Eric

[N170BP]

While the 180 guys use flaps 20 for takeoff, I think
a stock engined 170 just doesn't have enough "poop" to
pull the airplane along in a climb with those big flaps
set at 20 degrees.

All other things being equal, you get a better climb
rate with flaps 10 in a B than with flaps 20. At least
at flaps 10, the climb speed is faster which is nicer
for the cylinders.

The 10 degree notch is nice (mine has it). If I were to
fly my B IFR, I'd have to have a flaps 10 notch for
shooting approaches.

Bela P. Havasreti
'54 C-170B N170BP

[blueldr]

For crying out loud! If you want a ten degree flap notch, pull the quadrant out, notch the damn thing and reinstall it. Who in hell is ever going to disassemble the thing to check the part number? If they question it, just tell them that someone must have replaced it with a later model way back when.
Frankly, my experience has been that ten degrees doesn't do enough for the airplane to justify the work.

[GAHorn]

I've flown airplanes with and without the 10 degree flap setting and can't see where 10 degrees does anything for you. The performance data on both airplanes is identical, so there must not be any "official" effect.

[mit]

I've flown airplanes with and without the 10 degree flap setting and can't see where 10 degrees does anything for you. The performance data on both airplanes is identical, so there must not be any "official" effect.

I think that after a few 100hrs flying on floats, that you may find 10 degree's kind of nice. I wish I had cut it into mine when I had it apart.

If its not there you don't have the option, if it is there you don't have to use it.

[Dave Clark]

I did mine a couple of weeks ago. I used a very accurate tool on the flap to establish where to cut the notch and then a Dremel and file after I took it apart. As careful as I could be when it was assembled I ended up with about 8 degrees. Would have rather erred higher rater than lower. If I had it to do over I'd buy the part. I have not played with it much here at 5,000 ft elevation because I've frankly not been flying much. I can't wait to get back to sea level to test the performance difference though. My experimenting with holding the flaps "about right" last Summer told me that at least with the 180 Lyc it would get off a lot shorter and climb better too. My guess is that with the stock engine it wouldn't make that much difference.