what is "old style tail gear"?

[DaveF]

I need help interpreting the IPC.

In the 170B IPC, figure 29 TAILWHEEL INSTALLATION (SERIALS 20806 AND ON), page 54 upper right, there's a note that says: "NOTE: Parts marked "*" are necessary to install old style tail gear in 0591200-4 tailcone and 0591200-1 aft section."

Parts 29-2, -4,-5,-6,-7,-9,-19, and -20 are asterisked. Included are the U-bolt and stiffener, the main spring attach bolt, and other important-looking stuff.

Figure 23 specifies that tailcone and aft section as applicable to s/n 20267-26995. Let's assume we're dealing with an airplane in that s/n range.

What does the note mean?
1. Do some airplanes not use the "*" parts? I've never seen a 170B without them.
2. What is the difference between "old style tail gear" and "new style"? Figures 28 and 29 don't offer any more info.
3. Is there a service bulletin that clarifies this?


Your help is appreciated,
Dave

[GAHorn]

...Figure 23 specifies that tailcone and aft section as applicable to s/n 20267-26995. Let's assume we're dealing with an airplane in that s/n range.

What does the note mean?
1. Do some airplanes not use the "*" parts? I've never seen a 170B without them.
2. What is the difference between "old style tail gear" and "new style"? Figures 28 and 29 don't offer any more info.
3. Is there a service bulletin that clarifies this?


Your help is appreciated,
Dave

The early ragwing and early 170A aircraft used a small, steel, "box" tailwheel bracket. (You'd have to look at an earlier IPC to see that difference.) The late 170A and all later 170B* aircraft use the later, larger, aluminum "fish mouth" bracket. If an early bracket is converted to the later bracket, the *-marked items must be utilized. (Those parts are not ordinarily seen on the early brackets.)

The conversion is performed on early aircraft using a Cessna Service Bulletin, which members of the 170 Assoc. can obtain from their goofy parts/mx advisor.


*Correction: The later bracket was installed subsequent to serial 20805.

[DaveF]

Thanks, George.

You mean the box bracket p/n 0512125, shown in fig 28?

Your explanation makes perfect sense, though I'd assume if you're installing the design shown in figure 29 you'd use every part exactly as shown. Specifically identifying certain parts is redundant and confusing (to me, anyway).

I have seen a 170B with the old box bracket installed, presumably as part of a repair. Come to think of it, I've also seen airplanes with the U-bolt upside down, with extra spacers on the U-bolt, a Home Depot U-bolt with a thin piece of steel as the "stiffener" cross-bar, I saw an airplane with only three spring leaves, and one with the steering springs on the wheel end of the chains. I'll collect all the pictures and post them.

One more question about the IPC: What does NHA mean, as in "See figure 25 for NHA"?

Thanks,
Dave

[GAHorn]

I stand corrected, .... 170B's prior to 20805 had the box bracket.

NHA stands for "Next Higher Assembly".

[DaveF]

And to clarify my statement that "I've never seen a 170B without them", I meant to say: I've never seen a 170B that has the later (fishmouth) bracket without them.

And now I see the note on the bottom of page 49 that says "NOTE When ordering 0591200-4 tailcone for airplane with old-style tail gear (see figure 28 ), also order parts marked "*" on figure 29."

Thanks for the help.