Why 4130 tube?

To All:

Bob Babcock's conclusions closely match my own.

I believe anyone wishing to become airborne safely and at least cost should
devote a bit of time to the areas Bob has mentioned, then draw your own
conclusions.

On close examination a great deal of the aviation information available on the
internet turns out to be one novice parroting another. Tracked back to its
source, many of the Conventional Wisdoms espoused by the novice as fact turn
out to be tainted with commercialism, fallacious data meant to promote a
particular product or dealer.

Due to the anonymous nature of the internet I think the wiser course is to
assume EVERYTHING you read here is bull**** (yes, even this :-) and to not
accept any opinion as valid simply because it is popular.

Think for YOURSELF.

-R.S.Hoover

On 27 Mar 2004 23:12:41 GMT, (Veeduber) wrote:

To All:

Bob Babcock's conclusions closely match my own.

I believe anyone wishing to become airborne safely and at least cost should
devote a bit of time to the areas Bob has mentioned, then draw your own
conclusions.

On close examination a great deal of the aviation information available on the
internet turns out to be one novice parroting another. Tracked back to its
source, many of the Conventional Wisdoms espoused by the novice as fact turn
out to be tainted with commercialism, fallacious data meant to promote a
particular product or dealer.

Due to the anonymous nature of the internet I think the wiser course is to
assume EVERYTHING you read here is bull**** (yes, even this :-) and to not
accept any opinion as valid simply because it is popular.

precisely.


.....but I have this 1951 Auster fuselage out in the workshop that I
have beadblasted all myself and it did have one or two areas of
corrosion.
take the rudder for instance.
someone forgot to put in the bottom two drain holes.
that rudder had something like 50 tide lines formed in rust on the
inside of the cotton covering. the entire bottom steel bow of the
rudder was corroded almost totally away.
a quarter of an inch above the rust I hacksawed it through. there was
not one hint of rust inside the sound tube.
the combinations of alloy and surface passivation advocated over the
years actually do work.
the bow is repaired in 4130 and the bottom rib is stainless steel tig
welded.

4 reasons to use 4130.
the design was stressed for it.
it offers better strength to weight ratio
bare surfaces of it have better corrosion characterstics.
it is available in tube sizes which are neat fits inside each other.

if your design was intended for mild steel then go for it.
typically all the homebuilts by Roger Druine were designed for mild
steel fittings. make sure they are adequately corrosion proofed.

if your design was competently stressed for mild steel then go for it.

in either steel dont be stupid and use square tube. it is needlessly
heavier. (calc the amount of steel in an inch square with 1/8" wall
thickness and do the same for inch round with 1/8" wall thickness. the
reason isnt rocket science)

btw every time my tailwind does a heavy arrival I'm thankful that the
fuselage is 20% stronger than mild steel.
ymmv.
Stealth Pilot