Landing Gear Struts (Steel or Aluminum)

RCT44

RCT44

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Location
dallas
All,

This site has been so helpful to me as a new Super Decathlon owner, I am so appreciative. I have another question that might seem a bit silly but wanted to throw it out there anyway.

The 2005 Super D I purchased a couple of months ago came with a seemingly older POH with a gross max weight of 1800 lbs. When I asked the seller he said that's what he had always used as well. However, when I called ACA and spoke with one of the nice sales guys there he said in 2005 they were making the aircraft with both the aluminum and steel landing gear. I can't remember which but I believe he said the aluminum has a 1950 lbs gross max weight and raises the plane up a bit higher from the ground while the steel is the 1800 lbs gross max. He mentioned that on the struts that have the lower max weight, you can see the break fluid lines running down them. This makes me believe that I have the aluminum(?) struts which would have a gross max weight of 1950 but I am just unsure. Here is the POH I received with the plane and a few photos of the struts and plane. Just trying to figure this out as a 150 lbs difference is quite large and would be good to know.

Merry Christmas everyone!

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4 new photos · Oct 30 – Dec 12, 2021 📸

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Take a magnet off your refrigerator and see if it sticks to the gear leg. If it sticks, it's steel. The brake lines are internal on the aluminum legs
 
Just checked - they are aluminum - so does anyone know if I am correct with the 1950 lbs gross max weight assumption as it relates to the aluminum legs?
 
My iPad won't open your attachment. Here is a guess: If the factory says 2005 birds with aluminum legs are 1950, then you have the wrong AFM, or possibly only a POH.

The way you tell an AFM from a POH - the AFM has your N-number on it , a date, the serial #, and an authorized signature.
Mine has that on the cover page, and an FAA "Chief" signed it.

The POH cover page has no blanks for any of that. It just says "Pilot Operating Handbook."

The AFM is required to be on board - the POH cannot be substituted.
 
Bob Turner said:
My iPad won't open your attachment. Here is a guess: If the factory says 2005 birds with aluminum legs are 1950, then you have the wrong AFM, or possibly only a POH.

The way you tell an AFM from a POH - the AFM has your N-number on it , a date, the serial #, and an authorized signature.
Mine has that on the cover page, and an FAA "Chief" signed it.

The POH cover page has no blanks for any of that. It just says "Pilot Operating Handbook."

The AFM is required to be on board - the POH cannot be substituted.
Click to expand...


Bob - Thanks...I wonder if I can get a replacement if I only have a POH.
 
RCT

Two things add to the increased gross weight, the factory metal spar wings and the aluminum gear legs ....BUT.... they only add to the utility max gross weight, not the aerobatic max gross weight.

So, since you have both the wings and the gear legs, your utility category gross weight is 1950 but your aerobatic max gross weight stays at 1800.
 
ACA will sell you a replacement. Hold on to your hat - not cheap.

I doubt it is legal to simply find a clean copy and insert N #, but the Super Cub came out of the factory with a five page AFM stapled. That is, five loose pages with a staple!

Apparently all of them were the same - at that point all 150 Cubs rolled out of the factory with 1077# empty weight. Only the N-# and serial # were different , ship-to-ship.

Then they got tattered, worn, and lost, so it is rare to find a 150 Super Cub with anything resembling an AFM. To legally fly, you need one, but at a thousand bucks a pop, some owners resorted to a xerox copy with N- and serial #s penned in. You cannot tell.
 
Bob Turner said:
ACA will sell you a replacement. Hold on to your hat - not cheap.

I doubt it is legal to simply find a clean copy and insert N #, but the Super Cub came out of the factory with a five page AFM stapled. That is, five loose pages with a staple!

Apparently all of them were the same - at that point all 150 Cubs rolled out of the factory with 1077# empty weight. Only the N-# and serial # were different , ship-to-ship.

Then they got tattered, worn, and lost, so it is rare to find a 150 Super Cub with anything resembling an AFM. To legally fly, you need one, but at a thousand bucks a pop, some owners resorted to a xerox copy with N- and serial #s penned in. You cannot tell.
Click to expand...

haha - That's good to know, I have one in there but need to check what exactly it is. I will check and find out when back around hangar next week.
 
Bartman said:
RCT

Two things add to the increased gross weight, the factory metal spar wings and the aluminum gear legs ....BUT.... they only add to the utility max gross weight, not the aerobatic max gross weight.

So, since you have both the wings and the gear legs, your utility category gross weight is 1950 but your aerobatic max gross weight stays at 1800.
Click to expand...

That makes me feel better, I am happy to know I have the 1950 lbs gross weight! :) Obviously not during aerobatics but that makes perfect sense.
 
The story was that, after the wood spars, what was limiting the max gross weight was the prop clearance during the "drop test". since the aluminum gear are an inch taller they allowed them to up the weight while still protecting the prop when dropped in testing.

that's the way i understand it, details might be off a bit.

edit: mostly wrong
 
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Bartman said:
The story was that, after the wood spars, what was limiting the max gross weight was the prop clearance during the "drop test". since the aluminum gear are an inch taller they allowed them to up the weight while still protecting the prop when dropped in testing.

that's the way i understand it, details might be off a bit.
Click to expand...
That's accurate, except the wood spars were never a performance limitation, just a legal one. When Bellanca did the original certification with wood spars and steel gear, the MGW was 1800 due to prop clearance. When ACA revised the TC based on new drop tests in 2005, the aircraft tested had metal spars and aluminum gear, so the new MGW only applied to that configuration. Ergo legally you must have metal wings to get the MGW increase, but as a practical matter the spar type has zero to do with the change in capability.
 
I was under the impression Ed that you get a 100 lb increase with just the wings and then 50 more with the al. gear. the gear alone don't justify an increase though. no? it's in the tcds, everyone is sleeping so I'll look it up in a minute.

edit: all wrong
 
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On page 7 of the TCDS there's this;

N O T E 8 . T h e f o l l o w i n g c h a n g e s a p p l y t o 8 K C A B a i r c r a f t s e r i a l n u m b e r s 9 3 4 - 2 0 0 3 a n d u p a n d t o a n y
o t h e r 8 K C A B ( 1 8 0 h p . ) t h a t h a s 7 - 1 5 3 5 w i n g f r a m e s ( o r 7 - 1 5 2 1 c o v e r e d w i n g f r a m e s ) ,
e x t e n d e d m a i n g e a r ( g e a r l e g p a r t n u m b e r s 4 - 2 0 3 8 , 4 - 2 0 3 5 , o r 4 - 2 1 3 9 ) , a n d t h e A p p r o v e d
F l i g h t M a n u a l S u p p l e m e n t .

A i r s p e e d L i m i t s
( C A S ) N e v e r e x c e e d 2 0 0 m p h ( 1 7 4 k n o t s )
M a x i m u m S t r u c t u r a l C r u i s i n g 1 6 0 m p h ( 1 3 9 k n o t s )

M a n e u v e r i n g
N o r m a l C a t e g o r y 1 0 7 m p h ( 9 3 k n o t s )
A c r o b a t i c C a t e g o r y 1 3 0 m p h ( 1 1 3 k n o t s )

C . G . R a n g e
N o r m a l C a t e g o r y O p e r a t i o n :
( + 1 4 . 7 ) t o ( + 1 8 . 5 ) a t 1 9 5 0 l b .
( + 1 1 . 5 ) t o ( + 1 8 . 5 ) a t 1 5 5 0 l b . o r l e s s
A c r o b a t i c C a t e g o r y O p e r a t i o n :
( + 1 3 . 5 ) t o ( + 1 8 . 5 ) a t 1 8 0 0 l b .
( + 1 1 . 5 ) t o ( + 1 8 . 5 ) a t 1 5 5 0 l b . o r l e s s
Straightline variation between points given .

M a x i m u m W e i g h t
1 9 5 0 l b s . N o r m a l C a t e g o r y
1 8 0 0 l b s . A c r o b a t i c C a t e g o r y
Click to expand...

But before the factory made aluminum gear legs standard, there were metal spar factory wing airplanes being produced with steel gear and Bellanca 8KCABs with metal factory wings that only got the 100# increase. That's why I said above that the wings were the basis for the first 100 #'s. Maybe it wasn't the spars specifically, I can ask Dale when he's back in the shop on Monday.

edit: all wrong :(
 
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How would spar type affect MGW, other than structural strength? We know wood spar strength is not a constraint in normal category, since both spar types are rated for 6G at 1800lb in aerobatic category. You could do the math on the added force from the additional weight at normal category max G, but it will still be far below the strength of the spar.
 
I have no idea, I was just spitballin' but the numbers are what they are so Dale would be the next stop to figuring it out. Or Jerry if you really want the engineering analysis behind the numbers.
 
I'm not that worried about it, just chattering on a slow morning. Just pointing out that from a legal perspective, there are only 2 currently available options: metal spar and aluminum gear for 1950#, or any other combination for 1800#. Attempting to deduce the relative amount of MGW gain conferred by each component separately is meaningless, since no legal path exists to obtain such a change to your operating limitations. As far as the factory and FAA are concerned, it is all or nothing.
 
Ed, you can buy new metal spar wings for your Bellanca and get a 100# increase to your utility category max gross. I presume early ACA planes with factory wings and steel gear legs also have a 1900 utility max gross. I wasn't deducing it, just guessing as to why, assuming it was spars but it could be the rib/spar connection method, the strut attach points, whatever was updated for the metal spars if it isn't the spars themselves.

edit; that was all wrong
 
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Bartman said:
Ed, you can buy new metal spar wings for your Bellanca and get a 100# increase to your utility category max gross.
Click to expand...
For Super Decathlons, I think you are mistaken. What is your source?

The ACA metal wing FAQ on gross weight increase says "For 8KCAB with 180 horsepower, service letter 423 must be followed". Step 1 in the service letter is to install aluminum gear legs.

The SL does provide an alternative method of compliance by installing steel gear, but the part number is different than the steel gear legs originally installed by Bellanca. I believe these are the longer steel gear that ACA tried from 2003 to 2005 before going to aluminum, but that is an assumption.
 
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