Stupid Question from a newbie

Ok... I'm sure most anyone that reads this will think I'm an idiot, but
I'm so curious...

Could I build an ultralight airframe from EMT (electrical conduit) from
the local hardware store? I know that welding it would be inadvisable
due to the fact that it is galvanized (although I understand that
galvanizing can be 'stripped' thru use of an acid solution) but are
there other differences between standard hardware store emt tubing and
the steel tubing recommended for aircraft construction?

And now for the REALLLY stupid question... what about using PVC tubing?
I know that PVC is much more flexible than steel or aluminum tube, but
could it work? The reason I ask is because I keep thinking that if we
once made airframes out of wood, then wouldn't PVC be just about as
strong and more durable (long lasting?).

Rich

"expresstechonsite" wrote

Ok... I'm sure most anyone that reads this will think I'm an idiot, but
I'm so curious...

Could I build an ultralight airframe from EMT (electrical conduit) from
the local hardware store?

And now for the REALLLY stupid question... what about using PVC tubing?

Nope, and nope.

Both are not suitable for a number of reasons. EMT steel has no quality
tracking. It has poor weight to strength; way too heavy. It also is
brittle after welding. You would have a very heavy airplane, if you
compared it to typical aircraft steel tube.

PVC pipe is also very weak, for the weight. Added to that, the only way to
join them is with fittings, which do not give you many angles to use, and
they are weak, and split. The glue bonds are unreliable. Also, most of the
larger sized PVC pipes are foam core, and that makes them very weak, also.

I think you can't see the forest for the trees. The structure of the
airframe is a small price of a finished aircraft; the wheels, engine,
instruments, hardware, covering, and all the small bits are going to cost
you much more than the structure, perhaps by 3 or 4 times. (just a quick
guess)
--
Jim in NC

But it sure sounds fun to dream about it . . .

Gary G wrote:
But it sure sounds fun to dream about it . . .

So is dreaming about sleeping with a super model but neither is going to
happen. ;o)

Tony

("Anthony W" wrote)
But it sure sounds fun to dream about it . . .

So is dreaming about sleeping with a super model but neither is going to
happen. ;o)


If she's sleeping you've got a serious design flaw in your dream!


Montblack
I seldom remember my dreams. "Drat!"

Montblack wrote:
("Anthony W" wrote)
But it sure sounds fun to dream about it . . .

So is dreaming about sleeping with a super model but neither is going
to happen. ;o)


If she's sleeping you've got a serious design flaw in your dream!


Montblack
I seldom remember my dreams. "Drat!"

Lately I've been trying to keep my posts "G" rated. The sleeping is
after the more fun part. ;o)

Tony

In article . com,
"expresstechonsite" wrote:

Ok... I'm sure most anyone that reads this will think I'm an idiot, but
I'm so curious...

Could I build an ultralight airframe from EMT (electrical conduit) from
the local hardware store? I know that welding it would be inadvisable
due to the fact that it is galvanized (although I understand that
galvanizing can be 'stripped' thru use of an acid solution) but are
there other differences between standard hardware store emt tubing and
the steel tubing recommended for aircraft construction?

And now for the REALLLY stupid question... what about using PVC tubing?
I know that PVC is much more flexible than steel or aluminum tube, but
could it work? The reason I ask is because I keep thinking that if we
once made airframes out of wood, then wouldn't PVC be just about as
strong and more durable (long lasting?).

Not only would you not be the first to try, you would not be the first
to die or injure yourself resulting from said construction.

"expresstechonsite" wrote in message
And now for the REALLLY stupid question... what about using PVC tubing?
I know that PVC is much more flexible than steel or aluminum tube, but
could it work? The reason I ask is because I keep thinking that if we
once made airframes out of wood, then wouldn't PVC be just about as
strong and more durable (long lasting?).

Wood has excellent fatigue properties. Airplanes vibrate a lot. PVC could be
engineered to accept the loads of a light plane, though it wouldn't be as
efficient and it would probably crack in the near future at an inopportune
time.

D.

expresstechonsite wrote:

... The reason I ask is because I keep thinking that if we
once made airframes out of wood, then wouldn't PVC be just about as
strong and more durable (long lasting?).


Many woods have an excellent (small) wieght to strength ratio, much
better than PVC. But where wood really excels over plastics in
general is the weight to _stiffness_ ratio.

Strength determines how much force is needed to
permanently deform something. Stiffness determines
how much something deforms elastically (meaning it
rebounds to its original shape when the force is removed)
for a given force.

There are a number of other material properties relevant
to the issue of airplane construction as well.

That said, I have seen photos of a light plane made from
aluminum ladders. One segment was used for the wing,
another for the horizontal stabilizer and another for the
fuselage. The fuselage had another, shorter segment
stacked onto the other where the wing was joined,
sort of like a leaf spring.

--

FF