Blackburn B-48 'Firecrest'?

[MacMan85]

Hi

Does anyone have any pictures of the Blackburn B-48 (or YA-1) built in
1948ish? There were only two made before the project was cancelled....

TIA
Richard

[Dingo[_2_]]

"MacMan85" > wrote in message
...
> Hi
>
> Does anyone have any pictures of the Blackburn B-48 (or YA-1) built in
> 1948ish? There were only two made before the project was cancelled....
>
> TIA
> Richard

There's a nice one @ http://www.apda61.dsl.pipex.com/RBavpic4.htm
~~
Dingo ;~)

[Pete[_3_]]

Try this. It is from Wikipedia.
http://upload.wikimedia.org/wikipedia/commons/0/0a/Blackburn_Firecrest.png


"MacMan85" > wrote in message
...
> Hi
>
> Does anyone have any pictures of the Blackburn B-48 (or YA-1) built in
> 1948ish? There were only two made before the project was cancelled....
>
> TIA
> Richard

[Michael Huber[_2_]]

DAN wrote:
> here is one in flight

Let me go off on an OT tangent, if I may (and if I may not, ignore me, or
point me to group where that stuff is on-topic, please):

In a lot of in-flight pictures of prop planes, the props are slightly bent
backwards at the tips. Why is that? Since the prop is pulling the plane, I
would expect the thing to bend forward, if anything.

Michael.

[Randy Wilson]

Michael - my thought is that it is caused by the camera - perhaps shutter
speed or other issues. Here is an image of the same plane or type showing
the opposite, with the prop tips swept forward, for what it is worth.

Randy

"Michael Huber" > wrote in message
...
> DAN wrote:
>> here is one in flight
>
> Let me go off on an OT tangent, if I may (and if I may not, ignore me, or
> point me to group where that stuff is on-topic, please):
>
> In a lot of in-flight pictures of prop planes, the props are slightly bent
> backwards at the tips. Why is that? Since the prop is pulling the plane, I
> would expect the thing to bend forward, if anything.
>
> Michael.

[MacMan85]

Thanks! I've not seen that one before. I am really after actual photos
though, I have been planning a flying model of this aircraft for some
20 years and it's the detail that's elusive.
I did have the opportunity to look over the surviving works drawings a
long time ago, some of which I managed to photograph, but drawings
only give you the size of the parts!

On Sat, 26 Jan 2008 11:10:06 -0800, "Pete" >
wrote:

>Try this. It is from Wikipedia.
>http://upload.wikimedia.org/wikipedia/commons/0/0a/Blackburn_Firecrest.png
>
>
>"MacMan85" > wrote in message
...
>> Hi
>>
>> Does anyone have any pictures of the Blackburn B-48 (or YA-1) built in
>> 1948ish? There were only two made before the project was cancelled....
>>
>> TIA
>> Richard
>

[MacMan85]

Nice to see both those pictures on ther 'net. I have them both
already, though. RT651 is the version I'm trying to model.

On Sat, 26 Jan 2008 20:06:20 +0100, DAN > wrote:

>MacMan85 wrote:
>
>>Does anyone have any pictures of the Blackburn B-48 (or YA-1) built in
>>1948ish? There were only two made before the project was cancelled....
>
>Richard
>
>here is one in flight
>
>dan

[MacMan85]

Thanks! VF172, the MkII 'go-faster' version! (it has less dihedral on
the outer wing panels.)

On Sat, 26 Jan 2008 15:46:59 -0000, "Dingo"
> wrote:

>
>"MacMan85" > wrote in message
...
>> Hi
>>
>> Does anyone have any pictures of the Blackburn B-48 (or YA-1) built in
>> 1948ish? There were only two made before the project was cancelled....
>>
>> TIA
>> Richard
>
>There's a nice one @ http://www.apda61.dsl.pipex.com/RBavpic4.htm
>~~
>Dingo ;~)

[Michael Huber[_2_]]

John Smith wrote:
> Are you actually seeing the prop blade "bent" forward, or simply
> interpreting the blade pitch as the prop being bent forward?

I would say they look bent forward, especially the lowest one.

[Bob Harrington]

Michael Huber > wrote in news:fnhpoe$2pq$00$1
@news.t-online.com:

> John Smith wrote:
>> Are you actually seeing the prop blade "bent" forward, or simply
>> interpreting the blade pitch as the prop being bent forward?
>
> I would say they look bent forward, especially the lowest one.

I believe what you are seeing is an artifact of the camera shutter. Most
camera shutters that lie on the film plane (just above the film) consist
of a pair of horizontal or vertically moving curtains that are spring
loaded to zip across the film to make the exposure.

It takes a small, but not infinite, fraction of a second for each curtain
to cross the distance; they are timed so that each particular point on the
film receives light for the desired time, but with very short exposures
under bright conditions such as a sunlit sky, this results in the actual
distance between the leading and trailing shutter curtains being very
small, much smaller than the width of the film.

In effect, there is a narrow slit that moves across the film exposing it
as it goes. While the shutter speed may be set to only 1000th of second,
it could well take ten times that long for the slit to cover the full
frame of film. If something in the scene like a propeller is moving very
quickly, it can move visibly during that time, resulting in the apparent
warping of the propeller.

Older cameras especially can show this effect, as their shutters move more
slowly than most modern cameras.

Bob ^,,^

[Andrew Chaplin]

"Bob Harrington" > wrote in message
...
> Michael Huber > wrote in news:fnhpoe$2pq$00$1
> @news.t-online.com:
>
>> John Smith wrote:
>>> Are you actually seeing the prop blade "bent" forward, or simply
>>> interpreting the blade pitch as the prop being bent forward?
>>
>> I would say they look bent forward, especially the lowest one.
>
> I believe what you are seeing is an artifact of the camera shutter. Most
> camera shutters that lie on the film plane (just above the film) consist
> of a pair of horizontal or vertically moving curtains that are spring
> loaded to zip across the film to make the exposure.
>
> It takes a small, but not infinite, fraction of a second for each curtain
> to cross the distance; they are timed so that each particular point on the
> film receives light for the desired time, but with very short exposures
> under bright conditions such as a sunlit sky, this results in the actual
> distance between the leading and trailing shutter curtains being very
> small, much smaller than the width of the film.
>
> In effect, there is a narrow slit that moves across the film exposing it
> as it goes. While the shutter speed may be set to only 1000th of second,
> it could well take ten times that long for the slit to cover the full
> frame of film. If something in the scene like a propeller is moving very
> quickly, it can move visibly during that time, resulting in the apparent
> warping of the propeller.
>
> Older cameras especially can show this effect, as their shutters move more
> slowly than most modern cameras.

It also depends on the line of travel of the focal plane shutter. Earlier SLRs
had shutters that traveled horizontally and produced the effect. In the '70s
the trend was to vertical travel shutters; these significantly reduce the
phenomenon and allowed an increase in shutter speed with the shorter distance
to cross. The effect varies according to the direction of flight of the target
and the direction of travel of the shutter. It can be particularly pronounced
when one compares race cars; they can appear significantly longer or shorter
depending on how they cross the field of view.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
(If you're going to e-mail me, you'll have to get "yourfinger." out.)

[Michael Huber[_2_]]

Bob Harrington wrote:

> In effect, there is a narrow slit that moves across the film exposing it
> as it goes. *While the shutter speed may be set to only 1000th of second,
> it could well take ten times that long for the slit to cover the full
> frame of film. *If something in the scene like a propeller is moving very
> quickly, it can move visibly during that time, resulting in the apparent
> warping of the propeller.

That is interesting. Thank you!

[Grumpy AuContraire[_2_]]

Bob Harrington wrote:

> Michael Huber > wrote in news:fnhpoe$2pq$00$1
> @news.t-online.com:
>
>
>>John Smith wrote:
>>
>>>Are you actually seeing the prop blade "bent" forward, or simply
>>>interpreting the blade pitch as the prop being bent forward?
>>
>>I would say they look bent forward, especially the lowest one.
>
>
> I believe what you are seeing is an artifact of the camera shutter. Most
> camera shutters that lie on the film plane (just above the film) consist
> of a pair of horizontal or vertically moving curtains that are spring
> loaded to zip across the film to make the exposure.
>
> It takes a small, but not infinite, fraction of a second for each curtain
> to cross the distance; they are timed so that each particular point on the
> film receives light for the desired time, but with very short exposures
> under bright conditions such as a sunlit sky, this results in the actual
> distance between the leading and trailing shutter curtains being very
> small, much smaller than the width of the film.
>
> In effect, there is a narrow slit that moves across the film exposing it
> as it goes. While the shutter speed may be set to only 1000th of second,
> it could well take ten times that long for the slit to cover the full
> frame of film. If something in the scene like a propeller is moving very
> quickly, it can move visibly during that time, resulting in the apparent
> warping of the propeller.
>
> Older cameras especially can show this effect, as their shutters move more
> slowly than most modern cameras.
>
> Bob ^,,^
>


While I think that this is theoretically possible, I never experienced
such with tens of thousands of exposures from my M2 Leicas.

Maybe I need to see if I can get "creative."

<G>

JT