Glue it to it

I once amazed myself by bouncing a Flybaby about 8 or so feet in the
air, which I thought wasn't possible with just tires for shock absorption
..

I've worked on three Fly Babies, two from the eighties and one from the
seventies. Their glue joints were sturdy, and one of them had had some
awful rough landings which broke the 4130 landing gear and ruined some
of the welded steel fuselage attach fittings. Best I could tell the
glue in all three was resorcinol. Pete Bowers is an honored immortal
for designing such a great little wooden airplane that can flare 20
feet off the deck and still remain intact.

Somewhere in Ron Wanttaja's literature I read of a Fly Baby
cartwheeling and the wings did not collapse. Fuselage was damaged but
the pilot lived to tell the story.

On Thu, 07 Dec 2006 18:55:08 -0500, "J.Kahn" wrote:

I've worked on three Fly Babies, two from the eighties and one from the
seventies. Their glue joints were sturdy, and one of them had had some
awful rough landings which broke the 4130 landing gear and ruined some
of the welded steel fuselage attach fittings. Best I could tell the
glue in all three was resorcinol. Pete Bowers is an honored immortal
for designing such a great little wooden airplane that can flare 20
feet off the deck and still remain intact.

Somewhere in Ron Wanttaja's literature I read of a Fly Baby
cartwheeling and the wings did not collapse. Fuselage was damaged but
the pilot lived to tell the story.

I once amazed myself by bouncing a Flybaby about 8 or so feet in the
air, which I thought wasn't possible with just tires for shock absorption

I pegged a 4-G g-meter on a landing once. No damage, and that was on a gear leg
that had been improperly repaired from a crash 15 years earlier.

Ron Wanttaja

"Ron Wanttaja" wrote in message
...
On Thu, 07 Dec 2006 18:55:08 -0500, "J.Kahn"
wrote:

I've worked on three Fly Babies, two from the eighties and one from the
seventies. Their glue joints were sturdy, and one of them had had some
awful rough landings which broke the 4130 landing gear and ruined some
of the welded steel fuselage attach fittings. Best I could tell the
glue in all three was resorcinol. Pete Bowers is an honored immortal
for designing such a great little wooden airplane that can flare 20
feet off the deck and still remain intact.

Somewhere in Ron Wanttaja's literature I read of a Fly Baby
cartwheeling and the wings did not collapse. Fuselage was damaged but
the pilot lived to tell the story.

I once amazed myself by bouncing a Flybaby about 8 or so feet in the
air, which I thought wasn't possible with just tires for shock absorption

I pegged a 4-G g-meter on a landing once. No damage, and that was on a
gear leg
that had been improperly repaired from a crash 15 years earlier.

Ron Wanttaja

I've seen 2G's on landing, but never more than that. Of course, the RV's
gear probably has more spring to it than the Flybaby's tires, so my 2 G
arrival may not have any more energy than your 4, but 4??? Ouch. That's a
nice way to chip a tooth or something.

KB

On Thu, 7 Dec 2006 22:44:47 -0500, "Kyle Boatright"
wrote:

I pegged a 4-G g-meter on a landing once. No damage, and that was on a
gear leg
that had been improperly repaired from a crash 15 years earlier.

I've seen 2G's on landing, but never more than that. Of course, the RV's
gear probably has more spring to it than the Flybaby's tires, so my 2 G
arrival may not have any more energy than your 4, but 4??? Ouch. That's a
nice way to chip a tooth or something.

My back hurt for a couple of days. I posted the story to RAH back then;
reproduced:

http://www.bowersflybaby.com/stories/humility.HTM

I've got a couple of photos of the G-meter, been meaning to dig 'em up, scan
them in, and add one to the web page....

Ron Wanttaja

I've seen 2G's on landing, but never more than that. Of course, the RV's
gear probably has more spring to it than the Flybaby's tires, so my 2 G
arrival may not have any more energy than your 4, but 4??? Ouch. That's a
nice way to chip a tooth or something.


4Gs? That's just a good tight turn and you don't even need a G-Suit.

KB

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

"Ron Wanttaja" wrote

I pegged a 4-G g-meter on a landing once. No damage, and that was on a gear
leg
that had been improperly repaired from a crash 15 years earlier.

Thanks, Ron, for a partial confirmation of my concept.

See if you 'all can follow my reasoning, here.

A plane is commonly certified for -3 G's. That means all of the weight of the
plane is supported by the wing. Good engineering would place ultimate failure
at at least 1.5 times the 3 G's. That means the wing would hold 4.5 G's.

That means the wing was holding all of the weight of the plane. What would the
wing weigh, compared to the whole plane? Perhaps 1/4th of the weight?

If the wing were to fail from a landing, overflexing the wing, it would take a
landing of 4 times the 4.5 G's, or 18 G's.

Now, I give that it is unlikely to fail a wing from a hard landing, but people
do fail wings from crashes. (that is a landing, right? g) Wayne Hadley thinks
his crash was about 27 G's One has to think the gear absorbed at least 1/2 of
the force, right? So it follows that I would want my gear to stand up to at
least 10'G's before it folded flat, or ripped loose from the fuselage or wing.

So, if my gear were to stand up to drop test at 10 G's, and it had a 12" travel,
how high would the plane have to be dropped from, to achieve that force?
--
Jim in NC

So, just to turn the corner a little, If a person was to consider
buying a project that is
wood glued with epoxy but, started over 20 years ago, should that
person consider the
project with 20 year old epoxy connections or should he run the other
way?
Lou

On 14 Dec 2006 09:33:48 -0800, "Lou" wrote:


So, just to turn the corner a little, If a person was to consider
buying a project that is
wood glued with epoxy but, started over 20 years ago, should that
person consider the
project with 20 year old epoxy connections or should he run the other
way?
Lou

My Jungster II all wood construction is twenty years old this year. It
is stuck together with epoxy (T-88) and seems to be pretty sturdy yet.
It has been continuously hangered. It has been flown into the hot
south west and the damp middle west (Oshkosh) and lives in
California's central valley.

Ed Sullivan

Earlier, Lou wrote:
So, just to turn the corner a little, If a person was to consider
buying a project that is
wood glued with epoxy but, started over 20 years ago, should that
person consider the
project with 20 year old epoxy connections or should he run the other
way?

Plenty of 30-year-old composite sailplanes are glued together with
epoxy. Not only that, but about half of their structure (by weight)
_is_ epoxy. No sign of them spontaneously falling apart in the air.

So, I'd say that age itself isn't a factor. More important is how its
been stored or used, and the quality of the construction.

Thanks, Bob K.
http://www.hpaircraft.com/hp-24

Lou wrote:
should that
person consider the
project with 20 year old epoxy connections or should he run the other
way?
--------------------------------------------------------------------------

Dear Lou,

The question of durability involved boiling sample coupons then trying
to peel them apart.

Based on musical instruments assembled with low-tech hide glue, when
properly sealed, the moisture content of the wood -- and the strength
of the joints -- can remain stable for a hundred years or more. By
comparison, when not subjected to an outside agency such as heat, mold
or moisture, the joints produced by virtually all modern-day adhesives
are relatively ageless.

When purchasing someone else's project a detailed inspection by more
than one pair of eyes is always the wiser course. We now have more than
seventy years of experience with epoxies as an aircraft glue. There is
no inherent fault in using epoxy versus some other adhesive. What
changes is the inspection criteria and that information is best
supplied by someone familiar with the particular adhesive used in the
project.

-R.S.Hoover