Structural failure due to harmonic vibration

[Jay Honeck]

I've just finished reading the tale of the first round trip coast-to-
coast flight (which was accomplished by mid-air refueling,
occasionally from milk cans) from Spokane, WA to the east coast and
back, way back in 1929. They flew a distance of 10,000 miles (they
circled over airports whilst refueling) without landing. A
fascinating story, printed in a terrific magazine, "Aviation History".

One of the pilots, Nick Mamer, went on to a career with Northwest Air
Lines. The author of the article states that he was killed in 1938
flying a Lockheed 14 Super Electra over Montana when the plane crashed
after suffering structural failure due to harmonic vibration. All
passengers and crew were killed.

This is something I've never heard much about. I understand harmonic
vibration can destroy any structure, given enough time and amplitude
-- but wouldn't a pilot be aware of such an event occurring in
flight? I picture something similar to flying a twin without synching
the props -- the noise and vibration will just about drive you crazy.

I don't have any further information on this crash, so I suppose the
vibration could have destroyed the engine mounts, causing the engines
to depart the airframe. This would probably be impossible to detect
from the cockpit before disaster struck.

Does anyone have any more information on this phenomenon, and this
crash specifically? Also, are there any Super Electras still flying
and, if so, how did they solve this problem?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Dudley Henriques[_2_]]

Jay Honeck wrote:
> I've just finished reading the tale of the first round trip coast-to-
> coast flight (which was accomplished by mid-air refueling,
> occasionally from milk cans) from Spokane, WA to the east coast and
> back, way back in 1929. They flew a distance of 10,000 miles (they
> circled over airports whilst refueling) without landing. A
> fascinating story, printed in a terrific magazine, "Aviation History".
>
> One of the pilots, Nick Mamer, went on to a career with Northwest Air
> Lines. The author of the article states that he was killed in 1938
> flying a Lockheed 14 Super Electra over Montana when the plane crashed
> after suffering structural failure due to harmonic vibration. All
> passengers and crew were killed.
>
> This is something I've never heard much about. I understand harmonic
> vibration can destroy any structure, given enough time and amplitude
> -- but wouldn't a pilot be aware of such an event occurring in
> flight? I picture something similar to flying a twin without synching
> the props -- the noise and vibration will just about drive you crazy.
>
> I don't have any further information on this crash, so I suppose the
> vibration could have destroyed the engine mounts, causing the engines
> to depart the airframe. This would probably be impossible to detect
> from the cockpit before disaster struck.
>
> Does anyone have any more information on this phenomenon, and this
> crash specifically? Also, are there any Super Electras still flying
> and, if so, how did they solve this problem?
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>
Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
Reference that with propeller whirl mode, and you should come up with
all you'll ever need to know about resonant frequency as relates to
destructive force.
DH

--
Dudley Henriques

[Ron Wanttaja]

On Thu, 08 Nov 2007 09:46:52 -0500, Dudley Henriques > wrote:

> Jay Honeck wrote:
> > I've just finished reading the tale of the first round trip coast-to-
> > coast flight (which was accomplished by mid-air refueling,
> > occasionally from milk cans) from Spokane, WA to the east coast and
> > back, way back in 1929.

Hmmmm....interesting definition of "coast to coast." Spokane is "on the coast"
the say way Pittsburgh is (e.g., hundreds of miles inland).

> > One of the pilots, Nick Mamer, went on to a career with Northwest Air
> > Lines. The author of the article states that he was killed in 1938
> > flying a Lockheed 14 Super Electra over Montana when the plane crashed
> > after suffering structural failure due to harmonic vibration. All
> > passengers and crew were killed.
>
> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
> Reference that with propeller whirl mode, and you should come up with
> all you'll ever need to know about resonant frequency as relates to
> destructive force.

Wrong Electra, Dudley. Namer died in 1938 in the twin recip, twenty years
before the four-engine turboprop.

Wikipedia says, "Later, an investigation revealed that the tail structure had
failed on the new design from what is known as "natural resonance, or period of
vibration." Sounds like the natural frequency was too low....

Ron Wanttaja

[Tina]

Jay, somewhere I had seen a film of a flight test of a glider whose
wings started a distructive vibration. It was not pretty, the
amplitude of the vibration went from non existant to so great the wing
failed in what looked like 2 seconds. It happened so quickly it looked
doubtful the pilot could have reduced speed enough to stop it before
failure happened. I don't remember the details but the frequency might
have been the order of a couple of hertz -- so the wingtip went up a
little, down a little more, up even more, and after a few such cycles
as I remember it left the airplane.

My memory is not clear, but the suddeness of onset to failure was
something that remains vivid (wonder if it's an accurate memory?).

[Steven P. McNicoll]

"Jay Honeck" > wrote in message
ps.com...
>
> I've just finished reading the tale of the first round trip coast-to-
> coast flight (which was accomplished by mid-air refueling,
> occasionally from milk cans) from Spokane, WA to the east coast and
> back, way back in 1929. They flew a distance of 10,000 miles (they
> circled over airports whilst refueling) without landing. A
> fascinating story, printed in a terrific magazine, "Aviation History".
>

A coast-to-coast flight originating from Spokane? Spokane is in eastern
Washington, not far from the Idaho border. Must be nearly 400 miles from
the Pacific coast.

[Dudley Henriques[_2_]]

Ron Wanttaja wrote:
> On Thu, 08 Nov 2007 09:46:52 -0500, Dudley Henriques > wrote:
>
>> Jay Honeck wrote:
>>> I've just finished reading the tale of the first round trip coast-to-
>>> coast flight (which was accomplished by mid-air refueling,
>>> occasionally from milk cans) from Spokane, WA to the east coast and
>>> back, way back in 1929.
>
> Hmmmm....interesting definition of "coast to coast." Spokane is "on the coast"
> the say way Pittsburgh is (e.g., hundreds of miles inland).
>
>>> One of the pilots, Nick Mamer, went on to a career with Northwest Air
>>> Lines. The author of the article states that he was killed in 1938
>>> flying a Lockheed 14 Super Electra over Montana when the plane crashed
>>> after suffering structural failure due to harmonic vibration. All
>>> passengers and crew were killed.
>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>> Reference that with propeller whirl mode, and you should come up with
>> all you'll ever need to know about resonant frequency as relates to
>> destructive force.
>
> Wrong Electra, Dudley. Namer died in 1938 in the twin recip, twenty years
> before the four-engine turboprop.
>
> Wikipedia says, "Later, an investigation revealed that the tail structure had
> failed on the new design from what is known as "natural resonance, or period of
> vibration." Sounds like the natural frequency was too low....
>
> Ron Wanttaja

Don't know anything at all about the earlier crash. Reading his post I
assumed he wanted information on the CAUSE of the crash. Since the cause
seemed to be harmonic vibration, I naturally steered him to the 1960
Electra crashes involving resonant frequency and whirl mode.
It is interesting that the earlier crash was the earlier Electra.
As an added note, I would think that anyone wishing data on this
phenomenon would want to reference the Lockheed Electra crashes in the 60's.
DH

--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Ron Wanttaja > wrote in
:

> On Thu, 08 Nov 2007 09:46:52 -0500, Dudley Henriques
> > wrote:
>
>> Jay Honeck wrote:
>> > I've just finished reading the tale of the first round trip
>> > coast-to- coast flight (which was accomplished by mid-air
>> > refueling, occasionally from milk cans) from Spokane, WA to the
>> > east coast and back, way back in 1929.
>
> Hmmmm....interesting definition of "coast to coast." Spokane is "on
> the coast" the say way Pittsburgh is (e.g., hundreds of miles inland).
>
>> > One of the pilots, Nick Mamer, went on to a career with Northwest
>> > Air Lines. The author of the article states that he was killed in
>> > 1938 flying a Lockheed 14 Super Electra over Montana when the plane
>> > crashed after suffering structural failure due to harmonic
>> > vibration. All passengers and crew were killed.
>>
>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>> Reference that with propeller whirl mode, and you should come up with
>> all you'll ever need to know about resonant frequency as relates to
>> destructive force.
>
> Wrong Electra, Dudley. Namer died in 1938 in the twin recip, twenty
> years before the four-engine turboprop.
>
> Wikipedia says, "Later, an investigation revealed that the tail
> structure had failed on the new design from what is known as "natural
> resonance, or period of vibration." Sounds like the natural frequency
> was too low....
>


Yes, but the Later Electra was a classic lesson in resonant freq
failure, though quite a different thing to the failure that the earlier
Electra had. IIRC two L188s were lost when a precession induced whirl
set up a torsional action in the nacelles which in turn overstresed the
wing. in short, a bit of turbulence would get one prop wobbling whihc
would start the wing wobbling which would get the second prop on the
same side wobbling and the whole thing would increase in amplitude until
the wing failed.
A redisgend engine mount and reskinning the wings with the next gauge
aluminum cured the problem.


Bertie

[F. Baum]

On Nov 8, 7:46 am, Dudley Henriques > wrote:
> > Does anyone have any more information on this phenomenon, and this
> > crash specifically? Also, are there any Super Electras still flying
> > and, if so, how did they solve this problem?
> > --
>
> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
> Reference that with propeller whirl mode, and you should come up with
> all you'll ever need to know about resonant frequency as relates to
> destructive force.
> DH
>
Dud,
Isnt Harmonics and Whirl Mode Flutter two diferent things ? I used to
fly a turboprop that had Whirl Mode issues (And a crash resulting from
this), but not any resonance restrictions. On the other hand, I flew
Scouts that when equiped with a certain propeller (For banner towing)
had restrictions on certain RPM ranges because of resonance issues.
They were traeted as two entirely different restrictions.
KFB

[Jay Honeck]

> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
> Reference that with propeller whirl mode, and you should come up with
> all you'll ever need to know about resonant frequency as relates to
> destructive force.

Hmmm. If it happened to another Electra in 1960, that says a lot.
The crash I'm talking about happened in 1938.

I guess maybe they DIDN'T address the problem...?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Jay Honeck]

> A coast-to-coast flight originating from Spokane? Spokane is in eastern
> Washington, not far from the Idaho border. Must be nearly 400 miles from
> the Pacific coast.

My mistake. The author called the flight "trans-continental" and
"across America" -- which my brain translated into "coast-to-coast"
for some reason...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Steven P. McNicoll]

"Jay Honeck" > wrote in message
ps.com...
>
> Hmmm. If it happened to another Electra in 1960, that says a lot.
> The crash I'm talking about happened in 1938.
>
> I guess maybe they DIDN'T address the problem...?
>

Different aircraft.

[Steven P. McNicoll]

"Jay Honeck" > wrote in message
oups.com...
>>
>> A coast-to-coast flight originating from Spokane? Spokane is in eastern
>> Washington, not far from the Idaho border. Must be nearly 400 miles from
>> the Pacific coast.
>>
>
> My mistake. The author called the flight "trans-continental" and
> "across America" -- which my brain translated into "coast-to-coast"
> for some reason...
>

I think most people would agree with you. I'd say a "trans-continental"
flight that started in Spokane and proceeded east failed to transit about
400 miles worth of continent.

[Dudley Henriques[_2_]]

F. Baum wrote:
> On Nov 8, 7:46 am, Dudley Henriques > wrote:
>>> Does anyone have any more information on this phenomenon, and this
>>> crash specifically? Also, are there any Super Electras still flying
>>> and, if so, how did they solve this problem?
>>> --
>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>> Reference that with propeller whirl mode, and you should come up with
>> all you'll ever need to know about resonant frequency as relates to
>> destructive force.
>> DH
>>
> Dud,
> Isnt Harmonics and Whirl Mode Flutter two diferent things ? I used to
> fly a turboprop that had Whirl Mode issues (And a crash resulting from
> this), but not any resonance restrictions. On the other hand, I flew
> Scouts that when equiped with a certain propeller (For banner towing)
> had restrictions on certain RPM ranges because of resonance issues.
> They were traeted as two entirely different restrictions.
> KFB
>
Yes, in the true sense of definition. I haven't done any research on the
Electra crashes and the cause. It was my understanding that whirl mode
was a direct cause link. Any Harmonics interface would probably have
been considered as a peripheral result of how the whirl mode transmitted
through the resonant frequency of the structure.
Understanding the entire sequence is fairly complicated.
See Bertie's post above this one. I believe he has explained it fairly well.
DH

--
Dudley Henriques

[F. Baum]

On Nov 8, 9:29 am, Dudley Henriques > wrote:
>
> > Dud,
> > Isnt Harmonics and Whirl Mode Flutter two diferent things ? I used to
> > fly a turboprop that had Whirl Mode issues (And a crash resulting from
> > this), but not any resonance restrictions. On the other hand, I flew
> > Scouts that when equiped with a certain propeller (For banner towing)
> > had restrictions on certain RPM ranges because of resonance issues.

> > KFB
>
> Yes, in the true sense of definition. I haven't done any research on the
> Electra crashes and the cause. It was my understanding that whirl mode
> was a direct cause link.
Exactimundo. In the later Electra it was, but I doubt they had much
knowledge of this in 1938. In fact, Whirl mode wasnt much of an issue
until the 1950s when they started using small (By comparison)
lightwieght engine/gearboxes with massive props mounted on long moment
arms. I would argue that the harmonics/ resonance issue that brought
down the 1938 Electra is a completely different kettle of fish.

> Any Harmonics interface would probably have
> been considered as a peripheral result of how the whirl mode transmitted
> through the resonant frequency of the structure.

Whoa! Slow down, your making my head hurt ;).

> Understanding the entire sequence is fairly complicated.
> See Bertie's post above this one. I believe he has explained it fairly well.
> DH

Once again, Bertie saves the day
>
> --
> Dudley Henriques- Hide quoted text -
>
> - Show quoted text -

[Gig 601XL Builder]

Steven P. McNicoll wrote:
> "Jay Honeck" > wrote in message
> oups.com...
>>>
>>> A coast-to-coast flight originating from Spokane? Spokane is in
>>> eastern Washington, not far from the Idaho border. Must be nearly
>>> 400 miles from the Pacific coast.
>>>
>>
>> My mistake. The author called the flight "trans-continental" and
>> "across America" -- which my brain translated into "coast-to-coast"
>> for some reason...
>>
>
> I think most people would agree with you. I'd say a "trans-
> continental" flight that started in Spokane and proceeded east failed
> to transit about 400 miles worth of continent.

Would you count KSEA to KJFK as Trans-continental? If so the difference in
the distance of a great circle route flight would only be 193 miles.

[James Robinson]

Dudley Henriques > wrote:
>
> Ron Wanttaja wrote:
>>
>> Dudley Henriques
>>
>> > wrote:
>>>
>>> Jay Honeck wrote:
>>>>
>>>> One of the pilots, Nick Mamer, went on to a career with Northwest
>>>> Air Lines. The author of the article states that he was killed in
>>>> 1938 flying a Lockheed 14 Super Electra over Montana when the plane
>>>> crashed after suffering structural failure due to harmonic
>>>> vibration. All passengers and crew were killed.
>>>>
>>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>>> Reference that with propeller whirl mode, and you should come up
>>> with all you'll ever need to know about resonant frequency as
>>> relates to destructive force.
>>
>> Wrong Electra, Dudley. Namer died in 1938 in the twin recip, twenty
>> years before the four-engine turboprop.
>>
>> Wikipedia says, "Later, an investigation revealed that the tail
>> structure had failed on the new design from what is known as "natural
>> resonance, or period of vibration." Sounds like the natural
>> frequency was too low....
>>
> Don't know anything at all about the earlier crash. Reading his post I
> assumed he wanted information on the CAUSE of the crash. Since the
> cause seemed to be harmonic vibration, I naturally steered him to the
> 1960 Electra crashes involving resonant frequency and whirl mode.
> It is interesting that the earlier crash was the earlier Electra.
> As an added note, I would think that anyone wishing data on this
> phenomenon would want to reference the Lockheed Electra crashes in the
> 60's. DH

The Super Electra crash in Montana resulted from flutter. The aircraft
likely encountered turbulence, which set off the flutter, which in turn
tore the rudders and the tops of the vertical stabs off. The aircraft
was seen in a flat spin.

Flutter can be very destructive, with failure occurring within
seconds of onset.

It turned out that the test equipment Lockheed was using to determine
the natural frequency of the empennage gave inaccurate readings, so
the design was inadequate.

Here's a link to the accident report.

http://dotlibrary1.specialcollection.net/scripts/ws.dll?file&fn=8&name=*P%3A%5CDOT%5Cairplane%20accidents%5Cwebsearc h%5C011038.pdf

Note that it was finalized less than three weeks after the accident.
I guess they worked more quickly in those days.

[Dudley Henriques[_2_]]

F. Baum wrote:

> Exactimundo. In the later Electra it was, but I doubt they had much
> knowledge of this in 1938. In fact, Whirl mode wasnt much of an issue
> until the 1950s when they started using small (By comparison)
> lightwieght engine/gearboxes with massive props mounted on long moment
> arms. I would argue that the harmonics/ resonance issue that brought
> down the 1938 Electra is a completely different kettle of fish.
>

I haven't done any research at all on any of this; especially the 1938
crash.


--
Dudley Henriques

[Bertie the Bunyip[_19_]]

"F. Baum" > wrote in news:1194534592.304042.93710
@v23g2000prn.googlegroups.com:

> On Nov 8, 7:46 am, Dudley Henriques > wrote:
>> > Does anyone have any more information on this phenomenon, and this
>> > crash specifically? Also, are there any Super Electras still
flying
>> > and, if so, how did they solve this problem?
>> > --
>>
>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>> Reference that with propeller whirl mode, and you should come up with
>> all you'll ever need to know about resonant frequency as relates to
>> destructive force.
>> DH
>>
> Dud,
> Isnt Harmonics and Whirl Mode Flutter two diferent things ? I used to
> fly a turboprop that had Whirl Mode issues (And a crash resulting from
> this), but not any resonance restrictions. On the other hand, I flew
> Scouts that when equiped with a certain propeller (For banner towing)
> had restrictions on certain RPM ranges because of resonance issues.
> They were traeted as two entirely different restrictions.
> KFB



That's right. The whirl mode thing is a bit different, but there's a
common thread in that they both rely on frequency. I've flown quite a
few airplanes that had veboten RPM bands for various reasons. Lots of
old Radials with steel props had rather large bands because of the
probablity of turning the prop into a rather large piano string and
thereby putting too much stress on either the blade or the crank.
AFAIK prop inspection/replacement was the only AD ever put on a Stearman
75 on account of this problem. Generally it isn't an issue with wood
props, BTW, since their resonancy is intricate and wide rather than
narrow and focused.
Which is why you don't see a lot of stainless steel violins.
I'm not familiar with the tail problem on the Lockheed 10/12 so don;'t
even know if was related to harmonics from the prop. It's probable that
buffeting from the props could cause a resonant flutter in tail
surfaces, though. That airplane was rght at th eleading edge of
technology in it;s day, when cantilever aluminum structures were all the
rage. Beech had problems with their similar model 18 in that they
fjukked up the design of the center section leading, eventauly, to a few
shed wings and a nasty and seriously ugly AD to strap the outer panel
spars to each other to relieve it.

Bertie



Bertie

[Bertie the Bunyip[_19_]]

"F. Baum" > wrote in
oups.com:

> On Nov 8, 9:29 am, Dudley Henriques > wrote:
>>
>> > Dud,
>> > Isnt Harmonics and Whirl Mode Flutter two diferent things ? I used
>> > to fly a turboprop that had Whirl Mode issues (And a crash
>> > resulting from this), but not any resonance restrictions. On the
>> > other hand, I flew Scouts that when equiped with a certain
>> > propeller (For banner towing) had restrictions on certain RPM
>> > ranges because of resonance issues.
>
>> > KFB
>>
>> Yes, in the true sense of definition. I haven't done any research on
>> the Electra crashes and the cause. It was my understanding that whirl
>> mode was a direct cause link.
> Exactimundo. In the later Electra it was, but I doubt they had much
> knowledge of this in 1938. In fact, Whirl mode wasnt much of an issue
> until the 1950s when they started using small (By comparison)
> lightwieght engine/gearboxes with massive props mounted on long moment
> arms. I would argue that the harmonics/ resonance issue that brought
> down the 1938 Electra is a completely different kettle of fish.
>
>> Any Harmonics interface would probably have
>> been considered as a peripheral result of how the whirl mode
>> transmitted through the resonant frequency of the structure.
>
> Whoa! Slow down, your making my head hurt ;).
>
>> Understanding the entire sequence is fairly complicated.
>> See Bertie's post above this one. I believe he has explained it
>> fairly well. DH
>
> Once again, Bertie saves the day
>>

Ta da.

But I'm only repeaing what little i know about it.
Best check with an expert before you go out and design your own
airliner.


Bertie
>
>

[Bertie the Bunyip[_19_]]

Tina > wrote in news:1194534978.130955.37540
@q5g2000prf.googlegroups.com:

> Jay, somewhere I had seen a film of a flight test of a glider whose
> wings started a distructive vibration. It was not pretty, the
> amplitude of the vibration went from non existant to so great the wing
> failed in what looked like 2 seconds. It happened so quickly it looked
> doubtful the pilot could have reduced speed enough to stop it before
> failure happened. I don't remember the details but the frequency might
> have been the order of a couple of hertz -- so the wingtip went up a
> little, down a little more, up even more, and after a few such cycles
> as I remember it left the airplane.


Yeah, gliders are notorious for this sort of behaviour. It's not helped by
pilots lopping off or adding on large sections of wing for performance or
to fit the airplane into a class.

>
> My memory is not clear, but the suddeness of onset to failure was
> something that remains vivid (wonder if it's an accurate memory?).

Sounds like flutter, but it could be that the wings wer just at their
design limits. Plastic gliders are pretty flexible and this, combined with
control surfaces that have little or no mass or aerodynamic balance area
and a natural tendency to acclerate like you can't believe lead to a
relatively high incidence of flutter induced structural failures.

I've read of many and talked to one guy who had one. He shattered the
fuselage in a fraction of a second when his stab started rattling. It's one
of the reasons they wear 'chutes routinely.


Bertie

[Bertie the Bunyip[_19_]]

Jay Honeck > wrote in news:1194537883.203290.75060
@e9g2000prf.googlegroups.com:

>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>> Reference that with propeller whirl mode, and you should come up with
>> all you'll ever need to know about resonant frequency as relates to
>> destructive force.
>
> Hmmm. If it happened to another Electra in 1960, that says a lot.
> The crash I'm talking about happened in 1938.
>

Two completely different airplanes. You've obviously been drinking the tidy
bowl as well as sniffing the furntiure polish.


Bertie

[Bertie the Bunyip[_19_]]

Jay Honeck > wrote in
oups.com:

>> A coast-to-coast flight originating from Spokane? Spokane is in
>> eastern Washington, not far from the Idaho border. Must be nearly
>> 400 miles from the Pacific coast.
>
> My mistake. The author called the flight "trans-continental" and
> "across America" -- which my brain translated into "coast-to-coast"
> for some reason...

Oven cleaner is my bet


Bertie

[Steven P. McNicoll]

"Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net> wrote in message
...
>
> Would you count KSEA to KJFK as Trans-continental?
>

Yes.

[AES]

Out of physics curiousity, can anyone point to any references on induced
vibrations in aircraft (or any other mechanical) structures associated
with or caused by parametrically induced induced *subharmonic* or
*parametric* oscillations?

["Parametric oscillation" = a phenomena well known in electronics and
optics, in which if a structure has natural resonances with resonant
frequencies f1 and f2, and the structure is then excited or "pumped"
with a periodic force at a "pump" frequency fp = f1 + f2, this can cause
coupled oscillations to occur and grow at the "signal" and "idler"
frequencies f1 and f2.]

[Kloudy via AviationKB.com]

Tina wrote:
>Jay, somewhere I had seen a film of a flight test of a glider whose
>wings started a distructive vibration.

http://www.youtube.com/watch?v=mxFOHoy-UNQ

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums.aspx/aviation/200711/1

[Kloudy via AviationKB.com]

Tina wrote:
> I don't remember the details but the frequency might
>have been the order of a couple of hertz -- so the wingtip went up a
>little, down a little more, up even more, and after a few such cycles
>as I remember it left the airplane.

http://www.youtube.com/watch?v=8D7YCCLGu5Y

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums.aspx/aviation/200711/1

[Big John]

Jay

After the two crashes they found the problem and fixed it but then
they didn't sell good to airlines due to crash history.

Navy bought a large number (with MAD gear) after fix, that are now
configured to the P-3C Orion (ASW) configuration and many P-3's were
sold around the world in ASW confguration. Navy is still using them
while waiting for a new bird. There is a request out to industry for a
new bird???

Big John

****************************************


On Thu, 08 Nov 2007 06:09:52 -0800, Jay Honeck >
wrote:

>I've just finished reading the tale of the first round trip coast-to-
>coast flight (which was accomplished by mid-air refueling,
>occasionally from milk cans) from Spokane, WA to the east coast and
>back, way back in 1929. They flew a distance of 10,000 miles (they
>circled over airports whilst refueling) without landing. A
>fascinating story, printed in a terrific magazine, "Aviation History".
>
>One of the pilots, Nick Mamer, went on to a career with Northwest Air
>Lines. The author of the article states that he was killed in 1938
>flying a Lockheed 14 Super Electra over Montana when the plane crashed
>after suffering structural failure due to harmonic vibration. All
>passengers and crew were killed.
>
>This is something I've never heard much about. I understand harmonic
>vibration can destroy any structure, given enough time and amplitude
>-- but wouldn't a pilot be aware of such an event occurring in
>flight? I picture something similar to flying a twin without synching
>the props -- the noise and vibration will just about drive you crazy.
>
>I don't have any further information on this crash, so I suppose the
>vibration could have destroyed the engine mounts, causing the engines
>to depart the airframe. This would probably be impossible to detect
>from the cockpit before disaster struck.
>
>Does anyone have any more information on this phenomenon, and this
>crash specifically? Also, are there any Super Electras still flying
>and, if so, how did they solve this problem?

[Big John]

The T-28A had a bad problem. At normal cruise RPM the vibrations of
the big wide paddle bladed prop would cause the crank to fail at a
square cut corner on it.

They restricted constant operation in a wide band of RPM :o( and
undercut the square corner (where prop shaft met the crank throw) and
bird still lost props and became a glider.

Navy in their T-28B put a new engine and prop on it and no problems.
Some times it pays to go sloppy seconds :o)

Big John

On Thu, 8 Nov 2007 17:25:08 +0000 (UTC), Bertie the Bunyip >
wrote:

>"F. Baum" > wrote in news:1194534592.304042.93710
:
>
>> On Nov 8, 7:46 am, Dudley Henriques > wrote:
>>> > Does anyone have any more information on this phenomenon, and this
>>> > crash specifically? Also, are there any Super Electras still
>flying
>>> > and, if so, how did they solve this problem?
>>> > --
>>>
>>> Do a search for Lockheed Electra, Tell City Crash, 1960 I believe.
>>> Reference that with propeller whirl mode, and you should come up with
>>> all you'll ever need to know about resonant frequency as relates to
>>> destructive force.
>>> DH
>>>
>> Dud,
>> Isnt Harmonics and Whirl Mode Flutter two diferent things ? I used to
>> fly a turboprop that had Whirl Mode issues (And a crash resulting from
>> this), but not any resonance restrictions. On the other hand, I flew
>> Scouts that when equiped with a certain propeller (For banner towing)
>> had restrictions on certain RPM ranges because of resonance issues.
>> They were traeted as two entirely different restrictions.
>> KFB
>
>
>
>That's right. The whirl mode thing is a bit different, but there's a
>common thread in that they both rely on frequency. I've flown quite a
>few airplanes that had veboten RPM bands for various reasons. Lots of
>old Radials with steel props had rather large bands because of the
>probablity of turning the prop into a rather large piano string and
>thereby putting too much stress on either the blade or the crank.
>AFAIK prop inspection/replacement was the only AD ever put on a Stearman
>75 on account of this problem. Generally it isn't an issue with wood
>props, BTW, since their resonancy is intricate and wide rather than
>narrow and focused.
>Which is why you don't see a lot of stainless steel violins.
>I'm not familiar with the tail problem on the Lockheed 10/12 so don;'t
>even know if was related to harmonics from the prop. It's probable that
>buffeting from the props could cause a resonant flutter in tail
>surfaces, though. That airplane was rght at th eleading edge of
>technology in it;s day, when cantilever aluminum structures were all the
>rage. Beech had problems with their similar model 18 in that they
>fjukked up the design of the center section leading, eventauly, to a few
>shed wings and a nasty and seriously ugly AD to strap the outer panel
>spars to each other to relieve it.
>
>Bertie
>
>
>
>Bertie

[JGalban via AviationKB.com]

Jay Honeck wrote:
>
>Hmmm. If it happened to another Electra in 1960, that says a lot.
>The crash I'm talking about happened in 1938.
>
>I guess maybe they DIDN'T address the problem...?

Lockheed reused the Electra name. The 1930s Electra (think Amelia Earhart)
was a piston twin. The 1950s Electra was a 4 engine turboprop airliner.

http://www.constable.ca/sd076a.jpg

http://www.spain4uk.co.uk/images/wildlife/transport/electra_G-LOFE.jpg

John Galban=====>N4BQ (PA28-180)

--
Message posted via http://www.aviationkb.com

[JGalban via AviationKB.com]

Jay Honeck wrote:
>
>Hmmm. If it happened to another Electra in 1960, that says a lot.
>The crash I'm talking about happened in 1938.
>
>I guess maybe they DIDN'T address the problem...?

Lockheed reused the Electra name. The 1930s Electra (think Amelia Earhart)
was a piston twin. The 1950s Electra was a 4 engine turboprop airliner.

http://www.constable.ca/sd076a.jpg

http://www.spain4uk.co.uk/images/wildlife/transport/electra_G-LOFE.jpg

John Galban=====>N4BQ (PA28-180)

--
Message posted via http://www.aviationkb.com

[James Robinson]

Big John > wrote:

> Jay
>
> After the two crashes they found the problem and fixed it but then
> they didn't sell good to airlines due to crash history.
>
> Navy bought a large number (with MAD gear) after fix, that are now
> configured to the P-3C Orion (ASW) configuration and many P-3's were
> sold around the world in ASW confguration. Navy is still using them
> while waiting for a new bird. There is a request out to industry for a
> new bird???

That was a different airplane, and a different problem. The one Jay is
referring to were the orignal Electras, similar to what Amelia Earhart
flew. The Northwest flight was an L-14 Super Electra, a larger, more
powerful version of Amelia's L-10E.

http://en.wikipedia.org/wiki/Northwest_Airlines_Flight_2

What you are describing are the L-188 accidents in 1959/60. The were a
result of what was called the "whirl mode" failure.

The aircraft would perhaps have a hard landing, which would weaken or
break one of the struts in an engine mount. The engine would then be
able to move around slightly on the remaining mounts. When the aircraft
subsequently encountered moderate turbulence, the mounts would not be
able to restrain the engine from acting like a gyroscope, resulting in
the hub of the prop rotating in a circle. In one of the accidents, it
looked like the engine had moved up to 35 degrees out of line.

Unfortunately, when the crew reduced engine power because of the onset of
whirl mode, the frequency of the whirl mode would reduce, and eventually
would match that of the wing. The sympathetic vibration would grow in
magnitude until the wing structure failed.

[Bertie the Bunyip[_19_]]

Big John > wrote in
:

> The T-28A had a bad problem. At normal cruise RPM the vibrations of
> the big wide paddle bladed prop would cause the crank to fail at a
> square cut corner on it.
>
> They restricted constant operation in a wide band of RPM :o( and
> undercut the square corner (where prop shaft met the crank throw) and
> bird still lost props and became a glider.
>
> Navy in their T-28B put a new engine and prop on it and no problems.
> Some times it pays to go sloppy seconds :o)
>

He he.
Kind of surprising that the engine still had that weakness at that stage
of it's career. Variants had been around for over a decade and those hadn't
exactly been treated with kid gloves.
A friend of mine learned to fly in one of those.. I have to say I was
mightely impressed at the time. IIRC it was during a brief period in time
when the T-34 was being replaced with the initially troublesome T-34C, so
they were just going straight into the T-28b.
I remember seeing the books for the damned thing all over his apartment.
Unreal.


Bertie

[Bertie the Bunyip[_19_]]

Big John > wrote in
:

> Jay
>
> After the two crashes they found the problem and fixed it but then
> they didn't sell good to airlines due to crash history.
>
> Navy bought a large number (with MAD gear) after fix, that are now
> configured to the P-3C Orion (ASW) configuration and many P-3's were
> sold around the world in ASW confguration. Navy is still using them
> while waiting for a new bird. There is a request out to industry for a
> new bird???
>

Hey, why get a new airplane when you can just sit in a lawn chair with your
Wii and hunt virtual subs?

The Orion name was another they re-used, of course.
Why they did this is beyond me, it's not like they were ever going to run
out of constellations. Pity they never made a Cygnus, always been my
favorite.



Bertie

[Paul kgyy]

>
> Wikipedia says, "Later, an investigation revealed that the tail structure had
> failed on the new design from what is known as "natural resonance, or period of
> vibration." Sounds like the natural frequency was too low....
>
> Ron Wanttaja

Is this the same kind of flutter that affects the Bonanza V-tail?

[JGalban via AviationKB.com]

Bertie the Bunyip wrote:

>Why they did this is beyond me, it's not like they were ever going to run
>out of constellations.

Lockheed ran out of Constellations in 1958. :-))))))


John Galban=====>N4BQ (PA28-180)

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums.aspx/aviation/200711/1

[Big John]

Bertie

I did some service testing at Edwards on the T-28A. Things found
there. Bird had a bad 2P vibration in cockpit. Was caused by each of
the big wide blades of prop blowing big chunk of air back on the
original canopy which was much taller that the one ending up on bird.
Felt like sitting inside a base drum.

A C-47 or T-29 (forget which one) 3 blade'd prop was cut down to the
correct size and the three thinner blades cured the problem but Aero
Products had completed their order for the big fat props and they were
in storage in a warehouse so it was felt too expensive to can them and
put new props on bird.

Also the engine was a 7 cylinder 800 HP Wright and not the smoothest
running engine ever built. Almost 115 HP per cylinder. Chug,
chug,chug.

I ferried one of the first group (5) of birds delivered to the USAF
from LA to Enid, OK. Willie refused to accept the birds like they were
scheduled to due to the prop problem. Give to the multi engine school
:o)

We didn't have much trouble with the T-6 and students. When we finally
got the T-28A at Willie (after they machined the crank) there were
several wings bent which would have broken off and crashed if plastic.
I like metal wings.

Enough reminiscing :o)

Big John

*****************************************8

On Thu, 8 Nov 2007 19:35:58 +0000 (UTC), Bertie the Bunyip >
wrote:

>Big John > wrote in
:
>
>> The T-28A had a bad problem. At normal cruise RPM the vibrations of
>> the big wide paddle bladed prop would cause the crank to fail at a
>> square cut corner on it.
>>
>> They restricted constant operation in a wide band of RPM :o( and
>> undercut the square corner (where prop shaft met the crank throw) and
>> bird still lost props and became a glider.
>>
>> Navy in their T-28B put a new engine and prop on it and no problems.
>> Some times it pays to go sloppy seconds :o)
>>
>
>He he.
> Kind of surprising that the engine still had that weakness at that stage
>of it's career. Variants had been around for over a decade and those hadn't
>exactly been treated with kid gloves.
>A friend of mine learned to fly in one of those.. I have to say I was
>mightely impressed at the time. IIRC it was during a brief period in time
>when the T-34 was being replaced with the initially troublesome T-34C, so
>they were just going straight into the T-28b.
>I remember seeing the books for the damned thing all over his apartment.
>Unreal.
>
>
>Bertie

[Matt Whiting]

Jay Honeck wrote:
> I've just finished reading the tale of the first round trip coast-to-
> coast flight (which was accomplished by mid-air refueling,
> occasionally from milk cans) from Spokane, WA to the east coast and
> back, way back in 1929. They flew a distance of 10,000 miles (they
> circled over airports whilst refueling) without landing. A
> fascinating story, printed in a terrific magazine, "Aviation History".
>
> One of the pilots, Nick Mamer, went on to a career with Northwest Air
> Lines. The author of the article states that he was killed in 1938
> flying a Lockheed 14 Super Electra over Montana when the plane crashed
> after suffering structural failure due to harmonic vibration. All
> passengers and crew were killed.
>
> This is something I've never heard much about. I understand harmonic
> vibration can destroy any structure, given enough time and amplitude
> -- but wouldn't a pilot be aware of such an event occurring in
> flight?

If the Q is high enough, the amplitude of the vibration might ramp very
quickly to failure. Think control surface flutter. There isn't always
time to react.

Matt

[Bertie the Bunyip[_19_]]

"JGalban via AviationKB.com" <u32749@uwe> wrote in
news:7aec9d9cbf3fa@uwe:

> Bertie the Bunyip wrote:
>
>>Why they did this is beyond me, it's not like they were ever going to
>>run out of constellations.
>
> Lockheed ran out of Constellations in 1958. :-))))))
>

Groan!



Bertie

[Bertie the Bunyip[_19_]]

Big John > wrote in
:

> Bertie
>
> I did some service testing at Edwards on the T-28A. Things found
> there. Bird had a bad 2P vibration in cockpit. Was caused by each of
> the big wide blades of prop blowing big chunk of air back on the
> original canopy which was much taller that the one ending up on bird.
> Felt like sitting inside a base drum.


OK, you're going to have to tell me what 2P means...
>
> A C-47 or T-29 (forget which one) 3 blade'd prop was cut down to the
> correct size and the three thinner blades cured the problem but Aero
> Products had completed their order for the big fat props and they were
> in storage in a warehouse so it was felt too expensive to can them and
> put new props on bird.
>
> Also the engine was a 7 cylinder 800 HP Wright and not the smoothest
> running engine ever built. Almost 115 HP per cylinder. Chug,
> chug,chug.

Oh, OK, I thought they had 1830s or R2000's In fact, didn;t they
eventually go to R2800's with them? an awful lot bigger than a T-6 for a
"mere" 800hp.
>
> I ferried one of the first group (5) of birds delivered to the USAF
> from LA to Enid, OK. Willie refused to accept the birds like they were
> scheduled to due to the prop problem. Give to the multi engine school
>:o)
>
> We didn't have much trouble with the T-6 and students. When we finally
> got the T-28A at Willie (after they machined the crank) there were
> several wings bent which would have broken off and crashed if plastic.
> I like metal wings.

I like wood ones!


Bertie

[James Robinson]

Bertie the Bunyip > wrote:
>
> Big John > wrote:
>>
>> Bertie
>>
>> I did some service testing at Edwards on the T-28A. Things found
>> there. Bird had a bad 2P vibration in cockpit. Was caused by each of
>> the big wide blades of prop blowing big chunk of air back on the
>> original canopy which was much taller that the one ending up on bird.
>> Felt like sitting inside a base drum.
>
> OK, you're going to have to tell me what 2P means...

These are terms typically used in diagnosing engine vibration problems.

1P vibrations are those which are at the same frequency of the engine RPM.
2P vibrations are those which are at twice the frequency of the engine RPM.
1/2P vibrations are those which are at 1/2 the RPM of the engine.

If you have 1P vibrations, you look at things like prop balance or that you
have all the right size pistons in the engine.

With 2P vibrations, you look at things like the effect of two bladed props,
or anything that might be attached to the engine with 1:2 gearing.

[Big John]

Bertie

2P is twice propeller speed. With two blades it means each blade
caused one of the vibrations points each revolution.

The T-28B (Navy) version had a 1425 HP Wright R-1820. They must have
added some strength to wing for big engine? I never saw what mods they
did to 'A' version to make the 'B' ??????

The AF also modified some A's for VN with the R-1820 (think they were
called T-28D's???)

Long time ago in a far away land :o)

Big John

*****************************************

On Fri, 9 Nov 2007 00:36:27 +0000 (UTC), Bertie the Bunyip >
wrote:

>Big John > wrote in
:
>
>> Bertie
>>
>> I did some service testing at Edwards on the T-28A. Things found
>> there. Bird had a bad 2P vibration in cockpit. Was caused by each of
>> the big wide blades of prop blowing big chunk of air back on the
>> original canopy which was much taller that the one ending up on bird.
>> Felt like sitting inside a base drum.
>
>
>OK, you're going to have to tell me what 2P means...
>>
>> A C-47 or T-29 (forget which one) 3 blade'd prop was cut down to the
>> correct size and the three thinner blades cured the problem but Aero
>> Products had completed their order for the big fat props and they were
>> in storage in a warehouse so it was felt too expensive to can them and
>> put new props on bird.
>>
>> Also the engine was a 7 cylinder 800 HP Wright and not the smoothest
>> running engine ever built. Almost 115 HP per cylinder. Chug,
>> chug,chug.
>
>Oh, OK, I thought they had 1830s or R2000's In fact, didn;t they
>eventually go to R2800's with them? an awful lot bigger than a T-6 for a
>"mere" 800hp.
>>
>> I ferried one of the first group (5) of birds delivered to the USAF
>> from LA to Enid, OK. Willie refused to accept the birds like they were
>> scheduled to due to the prop problem. Give to the multi engine school
>>:o)
>>
>> We didn't have much trouble with the T-6 and students. When we finally
>> got the T-28A at Willie (after they machined the crank) there were
>> several wings bent which would have broken off and crashed if plastic.
>> I like metal wings.
>
>I like wood ones!
>
>
>Bertie

[Bertie the Bunyip[_19_]]

James Robinson > wrote in
:

> Bertie the Bunyip > wrote:
>>
>> Big John > wrote:
>>>
>>> Bertie
>>>
>>> I did some service testing at Edwards on the T-28A. Things found
>>> there. Bird had a bad 2P vibration in cockpit. Was caused by each of
>>> the big wide blades of prop blowing big chunk of air back on the
>>> original canopy which was much taller that the one ending up on
>>> bird. Felt like sitting inside a base drum.
>>
>> OK, you're going to have to tell me what 2P means...
>
> These are terms typically used in diagnosing engine vibration
> problems.
>
> 1P vibrations are those which are at the same frequency of the engine
> RPM. 2P vibrations are those which are at twice the frequency of the
> engine RPM. 1/2P vibrations are those which are at 1/2 the RPM of the
> engine.
>
> If you have 1P vibrations, you look at things like prop balance or
> that you have all the right size pistons in the engine.
>
> With 2P vibrations, you look at things like the effect of two bladed
> props, or anything that might be attached to the engine with 1:2
> gearing.
>

OK, got it. Thanks

Bertie

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:

>> We didn't have much trouble with the T-6 and students. When we finally
>> got the T-28A at Willie (after they machined the crank) there were
>> several wings bent which would have broken off and crashed if plastic.
>> I like metal wings.
>
> I like wood ones!
>
>
> Bertie
>
I once saw two Sumo wrestlers that I assume were hired by Bellanca,
jumping up and down on the wing tips of a Viking at one of the show
sites where I was performing. If I remember right, it was Bobby Bishop
or Debbie Gary who was demonstrating the Viking at that time.
VERY impressive....and a very strong airplane!

--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Big John > wrote in
:

>
> Bertie
>
> 2P is twice propeller speed. With two blades it means each blade
> caused one of the vibrations points each revolution.
>
> The T-28B (Navy) version had a 1425 HP Wright R-1820. They must have
> added some strength to wing for big engine? I never saw what mods they
> did to 'A' version to make the 'B' ??????
>
> The AF also modified some A's for VN with the R-1820 (think they were
> called T-28D's???)
>
> Long time ago in a far away land :o)

OK, I flew a DC 3 with the 1820 (the rest had Pratts) and I'm pretty sure
it was about 1100HP in that incarnation. I'll look it up now, but the T-28
is HUGE! The 1340 in the T-6 was rated at 600HP so I would have thought
pound for pound they would have had to go a lot more than an extra 33% for
it.

Bertie

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>
>>> We didn't have much trouble with the T-6 and students. When we finally
>>> got the T-28A at Willie (after they machined the crank) there were
>>> several wings bent which would have broken off and crashed if plastic.
>>> I like metal wings.
>>
>> I like wood ones!
>>
>>
>> Bertie
>>
> I once saw two Sumo wrestlers that I assume were hired by Bellanca,
> jumping up and down on the wing tips of a Viking at one of the show
> sites where I was performing. If I remember right, it was Bobby Bishop
> or Debbie Gary who was demonstrating the Viking at that time.
> VERY impressive....and a very strong airplane!
>


Yes, lovely airplane, though someone did pull one apart doing aerobatics as
I recall. It was someone who had a reputation for knowing what he was
doing, too, not someone who just decided to roll one one day.

I always thought the little LeBlond powered Junior would be a nice little
thing to have, or even the later Crusairs. Such a pretty airplane..


Bertie

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:
> Dudley Henriques > wrote in
> :
>
>> Bertie the Bunyip wrote:
>>
>>>> We didn't have much trouble with the T-6 and students. When we finally
>>>> got the T-28A at Willie (after they machined the crank) there were
>>>> several wings bent which would have broken off and crashed if plastic.
>>>> I like metal wings.
>>> I like wood ones!
>>>
>>>
>>> Bertie
>>>
>> I once saw two Sumo wrestlers that I assume were hired by Bellanca,
>> jumping up and down on the wing tips of a Viking at one of the show
>> sites where I was performing. If I remember right, it was Bobby Bishop
>> or Debbie Gary who was demonstrating the Viking at that time.
>> VERY impressive....and a very strong airplane!
>>
>
>
> Yes, lovely airplane, though someone did pull one apart doing aerobatics as
> I recall. It was someone who had a reputation for knowing what he was
> doing, too, not someone who just decided to roll one one day.
>
> I always thought the little LeBlond powered Junior would be a nice little
> thing to have, or even the later Crusairs. Such a pretty airplane..
>
>
> Bertie



I've flown the old Cruisair. Real nice airplane and I always thought
ahead of it's time.

--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>> Dudley Henriques > wrote in
>> :
>>
>>> Bertie the Bunyip wrote:
>>>
>>>>> We didn't have much trouble with the T-6 and students. When we
>>>>> finally got the T-28A at Willie (after they machined the crank)
>>>>> there were several wings bent which would have broken off and
>>>>> crashed if plastic. I like metal wings.
>>>> I like wood ones!
>>>>
>>>>
>>>> Bertie
>>>>
>>> I once saw two Sumo wrestlers that I assume were hired by Bellanca,
>>> jumping up and down on the wing tips of a Viking at one of the show
>>> sites where I was performing. If I remember right, it was Bobby
>>> Bishop or Debbie Gary who was demonstrating the Viking at that time.
>>> VERY impressive....and a very strong airplane!
>>>
>>
>>
>> Yes, lovely airplane, though someone did pull one apart doing
>> aerobatics as I recall. It was someone who had a reputation for
>> knowing what he was doing, too, not someone who just decided to roll
>> one one day.
>>
>> I always thought the little LeBlond powered Junior would be a nice
>> little thing to have, or even the later Crusairs. Such a pretty
>> airplane..
>>
>>
>> Bertie
>
>
>
> I've flown the old Cruisair. Real nice airplane and I always thought
> ahead of it's time.


well, when you look at the competition, no contest. Same engine as a
108-1 and a good thirty knots faster. Also, that wing is so elegant
looking I just now it has to do exactly what you ask with two finger
control.
I've seen a lot of them for sale recently for very small money, but I#ve
already got too many toys!


Bertie

[Ron Wanttaja]

On Thu, 8 Nov 2007 11:01:14 -0600, "Gig 601XL Builder"
<wrDOTgiaconaATsuddenlink.net> wrote:

> Steven P. McNicoll wrote:
> > I think most people would agree with you. I'd say a "trans-
> > continental" flight that started in Spokane and proceeded east failed
> > to transit about 400 miles worth of continent.
>
> Would you count KSEA to KJFK as Trans-continental? If so the difference in
> the distance of a great circle route flight would only be 193 miles.

That 192 miles includes a major mountain range (the Cascades)....

Ron Wanttaja

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:
> Dudley Henriques > wrote in
> :
>
>> Bertie the Bunyip wrote:
>>> Dudley Henriques > wrote in
>>> :
>>>
>>>> Bertie the Bunyip wrote:
>>>>
>>>>>> We didn't have much trouble with the T-6 and students. When we
>>>>>> finally got the T-28A at Willie (after they machined the crank)
>>>>>> there were several wings bent which would have broken off and
>>>>>> crashed if plastic. I like metal wings.
>>>>> I like wood ones!
>>>>>
>>>>>
>>>>> Bertie
>>>>>
>>>> I once saw two Sumo wrestlers that I assume were hired by Bellanca,
>>>> jumping up and down on the wing tips of a Viking at one of the show
>>>> sites where I was performing. If I remember right, it was Bobby
>>>> Bishop or Debbie Gary who was demonstrating the Viking at that time.
>>>> VERY impressive....and a very strong airplane!
>>>>
>>>
>>> Yes, lovely airplane, though someone did pull one apart doing
>>> aerobatics as I recall. It was someone who had a reputation for
>>> knowing what he was doing, too, not someone who just decided to roll
>>> one one day.
>>>
>>> I always thought the little LeBlond powered Junior would be a nice
>>> little thing to have, or even the later Crusairs. Such a pretty
>>> airplane..
>>>
>>>
>>> Bertie
>>
>>
>> I've flown the old Cruisair. Real nice airplane and I always thought
>> ahead of it's time.
>
>
> well, when you look at the competition, no contest. Same engine as a
> 108-1 and a good thirty knots faster. Also, that wing is so elegant
> looking I just now it has to do exactly what you ask with two finger
> control.
> I've seen a lot of them for sale recently for very small money, but I#ve
> already got too many toys!
>
>
> Bertie
>
It is indeed a beautiful wing. Getting the gear up could earn you a sore
shoulder once in a while (The Grumman F4F Wildcat took some work to get
the gear up and stowed as well) but aside from that, both were beautiful
to fly.



--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>> Dudley Henriques > wrote in
>> :
>>
>>> Bertie the Bunyip wrote:
>>>> Dudley Henriques > wrote in
>>>> :
>>>>
>>>>> Bertie the Bunyip wrote:
>>>>>
>>>>>>> We didn't have much trouble with the T-6 and students. When we
>>>>>>> finally got the T-28A at Willie (after they machined the crank)
>>>>>>> there were several wings bent which would have broken off and
>>>>>>> crashed if plastic. I like metal wings.
>>>>>> I like wood ones!
>>>>>>
>>>>>>
>>>>>> Bertie
>>>>>>
>>>>> I once saw two Sumo wrestlers that I assume were hired by
>>>>> Bellanca, jumping up and down on the wing tips of a Viking at one
>>>>> of the show sites where I was performing. If I remember right, it
>>>>> was Bobby Bishop or Debbie Gary who was demonstrating the Viking
>>>>> at that time. VERY impressive....and a very strong airplane!
>>>>>
>>>>
>>>> Yes, lovely airplane, though someone did pull one apart doing
>>>> aerobatics as I recall. It was someone who had a reputation for
>>>> knowing what he was doing, too, not someone who just decided to
>>>> roll one one day.
>>>>
>>>> I always thought the little LeBlond powered Junior would be a nice
>>>> little thing to have, or even the later Crusairs. Such a pretty
>>>> airplane..
>>>>
>>>>
>>>> Bertie
>>>
>>>
>>> I've flown the old Cruisair. Real nice airplane and I always thought
>>> ahead of it's time.
>>
>>
>> well, when you look at the competition, no contest. Same engine as a
>> 108-1 and a good thirty knots faster. Also, that wing is so elegant
>> looking I just now it has to do exactly what you ask with two finger
>> control.
>> I've seen a lot of them for sale recently for very small money, but
>> I#ve already got too many toys!
>>
>>
>> Bertie
>>
> It is indeed a beautiful wing. Getting the gear up could earn you a
> sore shoulder once in a while (The Grumman F4F Wildcat took some work
> to get the gear up and stowed as well) but aside from that, both were
> beautiful to fly.



Mmm, I can see the F4F would be nice to fly allright. wouldn't have
thought it would be too good to do a routine in, though. I don't know
what type ailerons it had or how they were rigged but nothing about it
screams out sportscar to me. Maybe it's just it's pugnacious looks. Cae
to set me straight?

Bertie

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:
> Dudley Henriques > wrote in
> :
>
>> Bertie the Bunyip wrote:
>>> Dudley Henriques > wrote in
>>> :
>>>
>>>> Bertie the Bunyip wrote:
>>>>> Dudley Henriques > wrote in
>>>>> :
>>>>>
>>>>>> Bertie the Bunyip wrote:
>>>>>>
>>>>>>>> We didn't have much trouble with the T-6 and students. When we
>>>>>>>> finally got the T-28A at Willie (after they machined the crank)
>>>>>>>> there were several wings bent which would have broken off and
>>>>>>>> crashed if plastic. I like metal wings.
>>>>>>> I like wood ones!
>>>>>>>
>>>>>>>
>>>>>>> Bertie
>>>>>>>
>>>>>> I once saw two Sumo wrestlers that I assume were hired by
>>>>>> Bellanca, jumping up and down on the wing tips of a Viking at one
>>>>>> of the show sites where I was performing. If I remember right, it
>>>>>> was Bobby Bishop or Debbie Gary who was demonstrating the Viking
>>>>>> at that time. VERY impressive....and a very strong airplane!
>>>>>>
>>>>> Yes, lovely airplane, though someone did pull one apart doing
>>>>> aerobatics as I recall. It was someone who had a reputation for
>>>>> knowing what he was doing, too, not someone who just decided to
>>>>> roll one one day.
>>>>>
>>>>> I always thought the little LeBlond powered Junior would be a nice
>>>>> little thing to have, or even the later Crusairs. Such a pretty
>>>>> airplane..
>>>>>
>>>>>
>>>>> Bertie
>>>>
>>>> I've flown the old Cruisair. Real nice airplane and I always thought
>>>> ahead of it's time.
>>>
>>> well, when you look at the competition, no contest. Same engine as a
>>> 108-1 and a good thirty knots faster. Also, that wing is so elegant
>>> looking I just now it has to do exactly what you ask with two finger
>>> control.
>>> I've seen a lot of them for sale recently for very small money, but
>>> I#ve already got too many toys!
>>>
>>>
>>> Bertie
>>>
>> It is indeed a beautiful wing. Getting the gear up could earn you a
>> sore shoulder once in a while (The Grumman F4F Wildcat took some work
>> to get the gear up and stowed as well) but aside from that, both were
>> beautiful to fly.
>
>
>
> Mmm, I can see the F4F would be nice to fly allright. wouldn't have
> thought it would be too good to do a routine in, though. I don't know
> what type ailerons it had or how they were rigged but nothing about it
> screams out sportscar to me. Maybe it's just it's pugnacious looks. Cae
> to set me straight?
>
> Bertie
Just flew it once on a ferry job. You would be right about it not being
very good for a show routine. The cockpit visibility alone could be
detrimental to your health in low altitude maneuvering. The power was
fine for the airframe but it flies like a truck. The ailerons were
surprisingly fast for a stubby fighter. The mid wing had a lot to do
with that I'm sure as it balanced out the mass in roll a bit better.
Aside from all this, it flew fine on the cross country I had it on and
the roll I did for the owner at the destination field was ok :-)


--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>> Dudley Henriques > wrote in
>> :
>>
>>> Bertie the Bunyip wrote:
>>>> Dudley Henriques > wrote in
>>>> :
>>>>
>>>>> Bertie the Bunyip wrote:
>>>>>> Dudley Henriques > wrote in
>>>>>> :
>>>>>>
>>>>>>> Bertie the Bunyip wrote:
>>>>>>>
>>>>>>>>> We didn't have much trouble with the T-6 and students. When we
>>>>>>>>> finally got the T-28A at Willie (after they machined the
crank)
>>>>>>>>> there were several wings bent which would have broken off and
>>>>>>>>> crashed if plastic. I like metal wings.
>>>>>>>> I like wood ones!
>>>>>>>>
>>>>>>>>
>>>>>>>> Bertie
>>>>>>>>
>>>>>>> I once saw two Sumo wrestlers that I assume were hired by
>>>>>>> Bellanca, jumping up and down on the wing tips of a Viking at
one
>>>>>>> of the show sites where I was performing. If I remember right,
it
>>>>>>> was Bobby Bishop or Debbie Gary who was demonstrating the Viking
>>>>>>> at that time. VERY impressive....and a very strong airplane!
>>>>>>>
>>>>>> Yes, lovely airplane, though someone did pull one apart doing
>>>>>> aerobatics as I recall. It was someone who had a reputation for
>>>>>> knowing what he was doing, too, not someone who just decided to
>>>>>> roll one one day.
>>>>>>
>>>>>> I always thought the little LeBlond powered Junior would be a
nice
>>>>>> little thing to have, or even the later Crusairs. Such a pretty
>>>>>> airplane..
>>>>>>
>>>>>>
>>>>>> Bertie
>>>>>
>>>>> I've flown the old Cruisair. Real nice airplane and I always
thought
>>>>> ahead of it's time.
>>>>
>>>> well, when you look at the competition, no contest. Same engine as
a
>>>> 108-1 and a good thirty knots faster. Also, that wing is so elegant
>>>> looking I just now it has to do exactly what you ask with two
finger
>>>> control.
>>>> I've seen a lot of them for sale recently for very small money, but
>>>> I#ve already got too many toys!
>>>>
>>>>
>>>> Bertie
>>>>
>>> It is indeed a beautiful wing. Getting the gear up could earn you a
>>> sore shoulder once in a while (The Grumman F4F Wildcat took some
work
>>> to get the gear up and stowed as well) but aside from that, both
were
>>> beautiful to fly.
>>
>>
>>
>> Mmm, I can see the F4F would be nice to fly allright. wouldn't have
>> thought it would be too good to do a routine in, though. I don't know
>> what type ailerons it had or how they were rigged but nothing about
it
>> screams out sportscar to me. Maybe it's just it's pugnacious looks.
Cae
>> to set me straight?
>>
>> Bertie
> Just flew it once on a ferry job. You would be right about it not
being
> very good for a show routine. The cockpit visibility alone could be
> detrimental to your health in low altitude maneuvering. The power was
> fine for the airframe but it flies like a truck. The ailerons were
> surprisingly fast for a stubby fighter. The mid wing had a lot to do
> with that I'm sure as it balanced out the mass in roll a bit better.
> Aside from all this, it flew fine on the cross country I had it on and
> the roll I did for the owner at the destination field was ok :-)

Mm, I'm amazed, That's almost exactly how I imagined it. I suppose from
reading about it's exploits in the Pacific and also because it looks
like it would make a dandy rubber FF model. Nothing that would make a
good FF model could be all that manueverable


Bertie
>
>