With regards to upgrading an early (1953 in this case) Cessna 180 to newer stock parts-- for example, removing the original p/n 0741001-1 & -2 gear legs & replacing with "185 gear" (also used on the 1964 and up C180) p/n 0741001-7 & -8, or installing a factory v-brace which was optional on the slightly later model 180's.
What's required: a logbook entry, a simple 337 with an IA return-to-service sign-off, or a 337 along with an STC or field approval?

The later 180's used 185 gear cuz the max weight was increased several hundred pounds. By putting on heavier gear I am pretty sure instead of the gear flexing you end up beating up the plane.

Tim

I'm guessing that most IA's would want to do it as a full field approval.

Although the definition of "form, fit, and function" is mostly the same, you can make a case that "form" covers the thickness of the gear leg. So if you're going from 11/16 to 3/4 thickness or whatever, the FAA could argue that this changes the form (a little), and so your IA might want to cover his ass.

Also, if the FAA wants to get nit-picky, a stiffer/thicker spring can be argued to change the function, meaning that it absorbs less impact than the thinner spring, transferring loads and impacts differently, throwing more stress into the airframe, yada yada yada.

If you do go to the heavier springs, it would make sense to go to larger tires with lower pressure, so they can soften some of that trauma before it gets into the airframe. Larger tires might also look a little nicer to some of the people on this forum

qmdv wrote:The later 180's used 185 gear cuz the max weight was increased several hundred pounds. By putting on heavier gear I am pretty sure instead of the gear flexing you end up beating up the plane.
Tim

This is a bit of a moot point for me The airplane was fitted with the 185 gear by a previous owner, I'm just trying to clean up the paperwork. Ditto the v-brace.
The (post-1964 180) 185 gear on an earlier 180 seems to be a fairly common and popular mod- kinda like putting 180 gear on a 170. FWIW the 1964 180's gross weight is 2800#, not terribly heavier than the 1953's 2550. Also FWIW, the 180 gear was changed in 1955 to incorporate 3" additional forward rake. Personally I think I would rather have the lighter-duty 1955 gear. I've never flown one with the early legs but I might even prefer that-- I understand it makes for quite a bit lighter tail on the ground (which can be both good and bad), but I've been told they're kinda mushy at full weight

hotrod150 wrote:

qmdv wrote:The later 180's used 185 gear cuz the max weight was increased several hundred pounds. By putting on heavier gear I am pretty sure instead of the gear flexing you end up beating up the plane.
Tim

This is a bit of a moot point for me The airplane was fitted with the 185 gear by a previous owner, I'm just trying to clean up the paperwork. Ditto the v-brace.
The (post-1964 180) 185 gear on an earlier 180 seems to be a fairly common and popular mod- kinda like putting 180 gear on a 170. FWIW the 1964 180's gross weight is 2800#, not terribly heavier than the 1953's 2550. Also FWIW, the 180 gear was changed in 1955 to incorporate 3" additional forward rake. Personally I think I would rather have the lighter-duty 1955 gear. I've never flown one with the early legs but I might even prefer that-- I understand it makes for quite a bit lighter tail on the ground (which can be both good and bad), but I've been told they're kinda mushy at full weight

I have some time in a 53. The gear is really spongy. Flexes a lot when taxing. Seemed a little easier to land

At first blush, "spongy" sounds bad....but then again, isn't the landing gear's job to soak up the impact of landing and the bumps when taxiing? In any event, I'm not planning on replacing the later-model gear that's on it, so I need to get the paperwork squared away.

hotrod150 wrote:.....so I need to get the paperwork squared away.

Or you could just play dumb and see if anybody ever notices the extra .050" of gear thickness

/\ that is what I was told to do... One IA says its on the type certificate, therefore he would not think twice about running it, another told me hell no, you flat cant do it, another said 337... I figured what the hell, I doubt any inspector will show up for a ramp check with a set of calipers, and even if he does, the extra .050 could be explained away as heavy paint... I didn't think twice about it and would play dumb if asked.. just how the hell would they expect the average pilot to notice the gear legs were .050" thicker on a new plane he just bought..

bart wrote:.......Or you could just play dumb and see if anybody ever notices the extra .050" of gear thickness

IMHO the problem isn't with the thicker gear leg, it's with the different rake. One of the things I want / need to do is re-weigh the airplane. In my experience, the W&B is one of the things most often found incorrect, esp in cases like mine where I don't think the airplane has ever been re-weighed since leaving the factory-- all the changes were "calculated". Doing an all-new W&B sheet, that different arm for the MLG axles is gonna show up like a sore thumb to an IA who's familiar with early 180's (like mine is). The other issue is that the W&B wasn't ever re-calc'd for the gear switch.
Ditto the problem with playing dumb about the v-brace--. I believe it's a Cessna v-brace which was part of the optional seaplane kit per the IPC, but anyone familiar with early 180's is gonna know it wasn't standard equipment.
There's been some other undocumented changes but I have copies of the applicable STC's so we can just do some "previously installed" 337's to get them squared away. I'll be ordering the CD for this airplane from the FAA so I'll see then what has or hasn't been 337'd already.

Sorry, I missed the part about your airplane being an early model without the forward swept gear...I guess that's a little different story. Seems like however you make your current gear legal would necessitate a new w/b anyways....plan on losing a bit of useful load in that process

As far as the V-brace, you're in the same boat...at the mercy of your IA again. Depends on how liberally they interpret the reg's and how much they have to lose if someday you should have an accident and they determine the cause to be an illegal v-brace installation

I wish being "legal" wasn't so damn confusing, time consuming and costly!! Maybe, then you wouldn't be dealing with this issue since the previous owners would have fully complied Every time I have to get an A&P signature makes me want to go experimental...

Wouldn't the raked forward gear be sort of like installing an O 470 K off a 1956 model year that is on the type data cert. and doesn't need a STC or 337?

The -1&2, -3&4, and -5&6 gear legs are in my Cessna 180 IPC, the -7&8 gear legs came along on the 1964 180G. The v-brace is shown in the 180 IPC also. My take on the situation is that they're stock Cessna 180 parts being installed on a Cessna 180, I figure we can just do a logbook entry or a simple 337 "removed p/n xxx gear legs & installed p/n xxx gear legs", and "installed Cessna seaplane -brace p/n xxx". My IA is good with the wrenches and good with paperwork, hopefully he'll be on the same page as me about logging this stuff.

I think you're right that it should be a log book entry. If the 5&6 legs are legs from a 62 180, they have the forward rake, and I'd assume that the 7&8 legs are the same, just a wee bit thicker.

whoops, wrong thread