Aileron spar lightening holes

[cbeyer]

The left aileron on my 52 model has 27 holes in the spar as shown on pages 11 and 20 of the IPC. The right aileron has only 8 holes. Both ailerons on a nearby 54 model also have 8 holes. There is no record of any changes in either log book. There are no A models on the field to compare. What is the significance of the 27 hole verses 8 hole spar other than the obvious? Was there a change in the manufacturing process in 1952 and this one got lucky and received one each or was it out of rig and required a heavy aileron on one side?

Regards,
CBeyer

[Bruce Fenstermacher]

A models use the same part number as B models and are pictured with 27 holes in the IPC. Could be the your aileron and both on the '54 are from a later year 172.

Interesting.

[Bruce Fenstermacher]

I've solved the mystery. Looking at the IPC for a 172 for 63 to 74 the ailerons are still pictured with 27 holes. But the IPC for the 75-76 year 172 shows only 8 holes though the aileron part number remains the same. 0523800 and 0523800-1 are the same part number that is used for all 170A through 1976 172s.

So you and the '54 have newer ailerons installed.

[cbeyer]

Thanks for the reply and the research,
The 52 has been my father's since 1965. I grew up with this airplane and I know the ailerons have not been off of it during that time period. I was astonished when I discovered they were different. I ran over to my 54 expecting to find 27 holes each, but found only 8 each. The 54 I have owned since 1982. Prior to that the ailerons could have been swapped out, but as I said before there is no log book entry to that effect, for what it is worth. I knew the 54 several years before I bought it and I know the previous owner, but I have not spoken to him since I discovered the hole situation. Grin. The early logs for the 54 were lost and replaced in 1958. so that does not follow either. It is a mystery. It makes little difference, but these things make studying old airplanes so interesting. So, my question to all is do you know how many holes are in your aileron spars?

CBeyer

[jrenwick]

I've solved the mystery. Looking at the IPC for a 172 for 63 to 74 the ailerons are still pictured with 27 holes. But the IPC for the 75-76 year 172 shows only 8 holes though the aileron part number remains the same. 0523800 and 0523800-1 are the same part number that is used for all 170A through 1976 172s.

So you and the '54 have newer ailerons installed.

I'm thinking that since the part number did not change, the IPC drawing might not have been changed at the same time the physical part changed. Looking at a range of 170 models might allow you to guess more closely when the changeover in the spars actually occurred.

Best Regards,

John

[hilltop170]

My 1951 170A has 27 on both sides.

[Bruce Fenstermacher]

I actually thought that perhaps the aileron changed sometime between 63 and 74 but the IPC not updated. That would fit both planes CBeyer is familiar with.

Now I have another little detail to check out when looking at planes and catolog in my memory though I usually don't look at many 172s.

[c170b53]

I think this post may also apply to the "B" flaps as in that there maybe different flaps from one side to another.

[jrenwick]

I think this post may also apply to the "B" flaps as in that there maybe different flaps from one side to another.

How are they different?

[c170b53]

Like the aileron, minor differences in the construction most notable at the (I'm guessing now from memory) inboard end which may or may not be closed.

[Bruce Fenstermacher]

The ailerons and flaps no matter what the year are mirror images from right to left.

[Bruce Fenstermacher]

Well just checked both of my ailerons and they are both 8 hole ailerons. Of course that means nothing as I've already established my wings are L-19 wings and we don't know what year they came from. So thinking these 8 hole ailerons might be L-19 I looked at a L-19 TM dated 1964 and it showed the 27 hole version.

We'll just keep looking at 172s and see if we can establish a pattern for what years are what.

[jrenwick]

My '55 170B has the 8-hole ailerons on both wings. So does a nearby '53 B-model. My logbooks don't show any ailerons being replaced.

John

[Bruce Fenstermacher]

.... My logbooks don't show any ailerons being replaced.

John

John my logs didn't show any wings being replaced with L-19 wings on my airplane until 2000. So when someone makes that statement forgive me if I roll my eyes just a wee bit.

It is interesting though. Hopefully more people will chime in with what they have and a pattern of years might develop.

[jrenwick]

.... My logbooks don't show any ailerons being replaced.

John

John my logs didn't show any wings being replaced with L-19 wings on my airplane until 2000. So when someone makes that statement forgive me if I roll my eyes just a wee bit.

I know; that's why I worded it that way.

John