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Time to Think ‘Horizontal’ for Future Space Launches



 
 
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  #21  
Old September 23rd 10, 01:51 PM posted to sci.space.policy
Jeff Findley
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Posts: 5,012
Default Time to Think ?Horizontal? for Future Space Launches

In article
tatelephone,
says...

On 9/22/2010 12:18 PM, Jeff Findley wrote:

That vertical landing on a mobile landing platform by those tail sitters
was abandoned in the 1950's for a reason. The transition from
horizontal to vertical flight was tricky, and the actual "landing" onto
those platforms was even trickier.


The Convair Pogo could be landed on any flat surface, but its one
vertical landing left its test pilot so spooked by the process that he
felt he was lucky to be alive, and they never tried it again.
When the French tried in in their straight-out-of-"Thunderbirds" SNECMA
Coléoptère, the result was the aircraft going out of control and the
pilot ejecting.


True. Any way it was tried, the "tail sitter" mode of landing was just
too dangerous to proceed to an operational vehicle.

Today, vertical landing with the aircraft in the horizontal position is
preferred (e.g. Harrier, V-22 Osprey, and pretty much every operational
helicopter). This eliminates the 90 degree rotation required by a tail
sitter which eliminates the requirement for the pilot to guide the craft
down with his back to the ground and his eyes pointed up at the sky.

Jeff
--
The only decision you'll have to make is
Who goes in after the snake in the morning?
  #22  
Old September 23rd 10, 02:00 PM posted to sci.space.policy
Jeff Findley
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Posts: 5,012
Default Time to Think ?Horizontal? for Future Space Launches

In article fd456a18-e444-4b5c-b8dc-cafde4fe0203
@u4g2000prn.googlegroups.com, says...

On Sep 22, 8:04*pm, Pat Flannery wrote:
On 9/22/2010 12:18 PM, Jeff Findley wrote:

That vertical landing on a mobile landing platform by those tail sitters
was abandoned in the 1950's for a reason. *The transition from
horizontal to vertical flight was tricky, and the actual "landing" onto
those platforms was even trickier.


The Convair Pogo could be landed on any flat surface, but its one
vertical landing left its test pilot so spooked by the process that he
felt he was lucky to be alive, and they never tried it again.
When the French tried in in their straight-out-of-"Thunderbirds" SNECMA
Coléoptère, the result was the aircraft going out of control and the
pilot ejecting.

Pat


The tail sitting system is well defined


No it's not. It was abandoned as an R&D program before the serious
problems were worked out of the system.

and modern avionics and
computing obviates any concern over the legends you repeat here
without any analysis.


This remains unproven in flight hardware.

VTOL aircraft like the Harrier had similar
teething difficulties which were addressed by improved avionics and
computer control.


Not true. The tail sitters were much more difficult to fly than the
early Harrier, due partly to the fact that the pilot was trying to land
with his back to the ground and eyes pointed up at the sky. At least in
a Harrier, the hand-eye coordination was more natural because the pilot
could easily see and feel what he was doing.

Plus, if the pilot got into real trouble, ejecting from a tail sitter
was more challenging than ejecting from a Harrier, again due to the
orientation of the pilot's seat during the tail sitting landing. Even
with its early teething problems, the Harriers were safer for the pilots
than tail sitters would have been. Thankfully, the tail sitters were
abandoned well before the stage where "teething problems" would likely
have killed several pilots.

Jeff
--
The only decision you'll have to make is
Who goes in after the snake in the morning?
  #24  
Old September 23rd 10, 08:24 PM posted to sci.space.policy
Pat Flannery
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Posts: 18,465
Default Time to Think ‘Horizontal’ for Future Space Launches

On 9/23/2010 1:15 AM, Sylvia Else wrote:
Thing is, you need a structure strong enough to tolerate the aerodynamic
forces of whatever speed the launch rail gives at its end point, but
then you need to carry that structure to up to where the second stage is
released, or orbit if you're going for SSTO.


....and God help you if there's a rabbit or rock sitting on that track
considering how fast you are going to be going down it on the launch sled.
You note whenever they show drawings of these things, they seem to throw
in a tunnel it's going to pass through before it reaches the end of the
track: http://www.g2mil.com/argus2.jpg
I don't know if that's just for effect, or if it's supposed to serve
some purpose - I had the thought that the tunnel might have thin sheets
of plastic on either end and be pumped full of pure oxygen to help light
the scramjets as the vehicle pierces the plastic walls on launch.

Pat

  #25  
Old September 23rd 10, 09:02 PM posted to sci.space.policy
Pat Flannery
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Posts: 18,465
Default Time to Think ?Horizontal? for Future Space Launches

On 9/23/2010 4:51 AM, Jeff Findley wrote:

True. Any way it was tried, the "tail sitter" mode of landing was just
too dangerous to proceed to an operational vehicle.


You could do it nowadays relying on GPS and automated landing control;
but trying to land something as big and light as a ET in a side wind
would be pure folly.
The Coleoptere had one advantage over the Pogo and Lockheed "Salmon"; in
it the pilot could pivot his seat ninety degrees so he ended up sitting
upright and looking out a window in the bottom of the aircraft's nose
during landing.
One of the big problems in the Pogo was that the pilot couldn't tell how
fast he was ascending or descending in vertical flight other than
looking at the altimeter or a "wind vane" mounted on the wingtip that
would at least tell him if he was rising or descending.
The big problem was that if it started descending too fast the aircraft
was going to tip over sideways under the influence of the wings going
backwards into the airstream, and end up doing a power dive straight
into the ground.
We can thank the Germans for coming up with this goofy idea:
http://www.luft46.com/heinkel/hewespe.html
http://www.luft46.com/heinkel/helerche.html
http://www.luft46.com/fw/fwtrieb.html

Today, vertical landing with the aircraft in the horizontal position is
preferred (e.g. Harrier, V-22 Osprey, and pretty much every operational
helicopter). This eliminates the 90 degree rotation required by a tail
sitter which eliminates the requirement for the pilot to guide the craft
down with his back to the ground and his eyes pointed up at the sky.


The VTOL aspect of the Coleoptere was only the start of the fun; it was
going to come flying out of a silo in the ground, and once in horizontal
flight the space between the circular wing and fuselage was going to
turn into a ramjet...like I said, the thing was straight out of
"Thunderbirds".
I've got Mook killfiled, so I'm only reading what you quote from him.
Is there some reason that he wants it to land vertically rather than
just glide-land with the inflatable wings?
If you are going to land it vertically, all you need to do is stick some
parachutes in the nose and have the weight of the rear plug-nozzle
engine make it fall tail-first towards the landing site.
There's no need for the goofy wings then.
In that case what you end up with is very similar to the SASSTO Saturn
IVB stage, with the plug nozzle serving as the heatshield:
http://www.up-ship.com/drawndoc/sdoc53ani.jpg

Pat
  #26  
Old September 23rd 10, 09:07 PM posted to sci.space.policy
Pat Flannery
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Posts: 18,465
Default Time to Think ?Horizontal? for Future Space Launches

On 9/23/2010 5:00 AM, Jeff Findley wrote:

Plus, if the pilot got into real trouble, ejecting from a tail sitter
was more challenging than ejecting from a Harrier, again due to the
orientation of the pilot's seat during the tail sitting landing. Even
with its early teething problems, the Harriers were safer for the pilots
than tail sitters would have been. Thankfully, the tail sitters were
abandoned well before the stage where "teething problems" would likely
have killed several pilots.


You know, I'd never thought about that in relation to the Coleoptere,
but the pilot did eject from it when it was in the vertical flight mode;
they must have had a system that swung the seat back to horizontal
flight position before firing.

Pat
  #27  
Old September 23rd 10, 09:19 PM posted to sci.space.policy
Quadibloc
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Posts: 7,018
Default Time to Think ‘Horizontal’ for Future Space Launches

The title of this post suggests... something else instead of a change
in mission profiles.

However, I don't think one can really recommend seducing and
blackmailing influential politicians as an effective way to obtain
more space funding. Although, no doubt, it could make for a plot for
an exciting movie.

John Savard
  #28  
Old September 23rd 10, 10:09 PM posted to sci.space.policy
William Mook[_2_]
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Posts: 3,840
Default Time to Think ?Horizontal? for Future Space Launches

On Sep 23, 9:00*am, Jeff Findley wrote:
In article fd456a18-e444-4b5c-b8dc-cafde4fe0203
@u4g2000prn.googlegroups.com, says...





On Sep 22, 8:04*pm, Pat Flannery wrote:
On 9/22/2010 12:18 PM, Jeff Findley wrote:


That vertical landing on a mobile landing platform by those tail sitters
was abandoned in the 1950's for a reason. *The transition from
horizontal to vertical flight was tricky, and the actual "landing" onto
those platforms was even trickier.


The Convair Pogo could be landed on any flat surface, but its one
vertical landing left its test pilot so spooked by the process that he
felt he was lucky to be alive, and they never tried it again.
When the French tried in in their straight-out-of-"Thunderbirds" SNECMA
Coléoptère, the result was the aircraft going out of control and the
pilot ejecting.


Pat


The tail sitting system is well defined


No it's not. *It was abandoned as an R&D program before the serious
problems were worked out of the system.

and modern avionics and
computing obviates any concern over the legends you repeat here
without any analysis. *


This remains unproven in flight hardware.

VTOL aircraft like the Harrier had similar
teething difficulties which were addressed by improved avionics and
computer control.


Not true. *The tail sitters were much more difficult to fly than the
early Harrier,


Not true

http://www.youtube.com/watch?v=6-wc6-yspYw
http://www.youtube.com/watch?v=9t731Y2tSqQ
http://www.youtube.com/watch?v=Nh9dhBJY010
http://www.youtube.com/watch?v=XJ1D_eiHafY
http://www.youtube.com/watch?v=Ja9kFc1BdT8

Get a POGO model and try it for yourself! lol.

Without wings - the DCX took off and landed vertically

http://www.youtube.com/watch?v=wv9n9Casp1o

So did the JAXA RVT

http://www.youtube.com/watch?v=-irOfrXy4N4

What I propose, is rather simple.

(1) parallel staging of an existing airframe;
(2) equipped with thermal protection for ballistic re-entry
(3) equipped with lift systems to act as glider
(4) recovery of the glider down-range
(5) release of the glider near the launch center
(6) transition to vertical flight
(7) vertical landing

The procedure and technology is simple and provides a system of
minimal weight, complexity and innovation to deliver a maximum of
performance.

due partly to the fact that the pilot was trying to land
with his back to the ground and eyes pointed up at the sky.


This isn't an issue in an unpiloted craft.

*At least in
a Harrier, the hand-eye coordination was more natural because the pilot
could easily see and feel what he was doing.


This is not an issue for an unpiloted vehicle.

The Hawker P-1127 had significant difficulties and design problems
from the early stages in the 1950s. These difficulties led to Convair
proposing a simpler easier to build alternative with far fewer
problems.

Plus, if the pilot got into real trouble, ejecting from a tail sitter
was more challenging than ejecting from a Harrier, again due to the
orientation of the pilot's seat during the tail sitting landing. *


This is not an issue for an unpiloted vehicle.

Even
with its early teething problems, the Harriers were safer for the pilots
than tail sitters would have been.


In the 1950s the tail sitters were obviously less complex and
dangerous than redirecting jet exhaust

http://www.youtube.com/watch?v=f8W2SI4c93s

The P-1127 crashed in 1963 at the Paris Air Show and the P-1154 was
canceled when it became clear that its performance would never be what
it was promised to be.

*Thankfully, the tail sitters were
abandoned well before the stage where "teething problems" would likely
have killed several pilots.


No tail sitters have crashed. Many Harriers have.

http://www.youtube.com/watch?v=1USNC3Ozw18
http://www.youtube.com/watch?v=HB5CXlEALJ0
http://www.youtube.com/watch?v=VGE7AYe7DtY

Jeff
--
The only decision you'll have to make is
Who goes in after the snake in the morning?


  #29  
Old September 23rd 10, 10:11 PM posted to sci.space.policy
William Mook[_2_]
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Posts: 3,840
Default Time to Think ?Horizontal? for Future Space Launches

On Sep 23, 4:07*pm, Pat Flannery wrote:
On 9/23/2010 5:00 AM, Jeff Findley wrote:

Plus, if the pilot got into real trouble, ejecting from a tail sitter
was more challenging than ejecting from a Harrier, again due to the
orientation of the pilot's seat during the tail sitting landing. *Even
with its early teething problems, the Harriers were safer for the pilots
than tail sitters would have been. *Thankfully, the tail sitters were
abandoned well before the stage where "teething problems" would likely
have killed several pilots.


You know, I'd never thought about that in relation to the Coleoptere,
but the pilot did eject from it when it was in the vertical flight mode;
they must have had a system that swung the seat back to horizontal
flight position before firing.

Pat


Yeah, many of Jeff's objections ignore the possibility of designing a
crew seat and avionics to avoid the problems he outlines - but the use
of this technology in an unpiloted vehicle makes the points moot
anyway.
  #30  
Old September 23rd 10, 10:14 PM posted to sci.space.policy
William Mook[_2_]
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Posts: 3,840
Default Time to Think ?Horizontal? for Future Space Launches

On Sep 23, 8:51*am, Jeff Findley wrote:
In article
tatelephone,
says...



On 9/22/2010 12:18 PM, Jeff Findley wrote:


That vertical landing on a mobile landing platform by those tail sitters
was abandoned in the 1950's for a reason. *The transition from
horizontal to vertical flight was tricky, and the actual "landing" onto
those platforms was even trickier.


The Convair Pogo could be landed on any flat surface, but its one
vertical landing left its test pilot so spooked by the process that he
felt he was lucky to be alive, and they never tried it again.
When the French tried in in their straight-out-of-"Thunderbirds" SNECMA
Coléoptère, the result was the aircraft going out of control and the
pilot ejecting.


True. *Any way it was tried, the "tail sitter" mode of landing was just
too dangerous to proceed to an operational vehicle.

Today, vertical landing with the aircraft in the horizontal position is
preferred (e.g. Harrier, V-22 Osprey, and pretty much every operational
helicopter). *This eliminates the 90 degree rotation required by a tail
sitter which eliminates the requirement for the pilot to guide the craft
down with his back to the ground and his eyes pointed up at the sky.

Jeff
--
The only decision you'll have to make is
Who goes in after the snake in the morning?


Still, the tail sitter is rather simple to carry out as a method to
recover through automatic means an ET sized booster with minimal added
mass and minimal complexity.

If you'd fly a model aircraft to a vertical landing transitioning from
horizontal flight, you'd see how simple it is.

Restarting an aerospike engine to carry out a landing similar to that
of the DC-X provides a simple light weight approach to booster
recovery.
 




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