Another XCOR Milestone
Greg D. Moore (Strider)
"Douglas Ellison" <mai...@douglasellison.co.uk> wrote in message
news:afine7$epand$1...@ID-115030.news.dfncis.de...
>
> > ----------------------------------------------------------------
> > "Limited funds are a blessing, not Jeff Greason
> > a curse. Nothing encourages creative President & Eng. Mgr.
> > thinking in quite the same way." --L. Yau XCOR Aerospace
> > <www.xcor.com> <jgre...@xcor.com>
>
>
> LOVE the signature.
>
> Reminds me of Beagle 2 a great deal
>
I think it's one of the reasons the ".com" I work for is still in business.
We didn't have hundreds of millions thrown at us. We had to be scrappy.
(One company we dealt with spent thousands on 53" plasma screen displays
(with a 2-3 year rated max lifetime) for their NOC. We went with a bunch
17" CRTs. You can buy a lot of CRT's for the price of one of those big
puppies.)
More OT, I think this is an excellent example of incremental testing and its
value.
> Doug
>
>
>
Cameron Dorrough
"dead-stick" land the EZ-Rocket? I can't find anything on the (excellent,
BTW) web-site - just a statement that they have to.
I would have thought that the engines could be throttled back or that they
could just kill one..? No?
TIA, Cameron.
Bruce Hoult
"Cameron Dorrough" <cdor...@spamspamgoawayrmna.com.au> wrote:
I don't think the current engines are throttlable, or at least not to
the extent that would be needed. The EZ-Rocket still climbs pretty
briskly on a single engine (about the same as with the regular piston
engine it says somewhere on the web site) so there's no chance at all of
landing with one going.
Besides, what's the problem with a dead-stick landing? They're
perfectly safe and controllable things (I've done hundreds myself,
including one today) and if they do it with fuel onboard then with a
rocket full power is always some small fraction of a second away...
-- Bruce
Alejandro Zuzek
just one rocket engine is roughly the same as the
standard EZ piston engine at full power.
Cameron Dorrough
news:bruce-878089....@copper.ipg.tsnz.net...
Thanks, guys. No problem.. just thinking ahead and wasn't sure. I know
that many rocket motors are throttlable and I suppose someone at XCOR will
be working on it in the back room.
I'm guessing that not being able to throttle the engines would restrict
airframe design somewhat, since you are forced into a design that can glide
right from the drawing board. If your typical modern airliner had had a
design requirement for a better glide-slope than your average housebrick, we
would have skipped Comets, 707's, 727's, DC-9's, DC-10's, the original 747's
and many others and only just recently have stopped travelling by ship! :-)
I have been following events at ArmadilloAerospace and having throttlable
engines (of any sort) allows for amazing design flexibility and control.
Cameron.
Bruce Hoult
"Cameron Dorrough" <cdor...@spamspamgoawayrmna.com.au> wrote:
> I'm guessing that not being able to throttle the engines would restrict
> airframe design somewhat, since you are forced into a design that can glide
> right from the drawing board. If your typical modern airliner had had a
> design requirement for a better glide-slope than your average housebrick, we
> would have skipped Comets, 707's, 727's, DC-9's, DC-10's, the original 747's
> and many others and only just recently have stopped travelling by ship! :-)
Actually, many airliners glide very well. The main performance criteria
for a glider is the lift-to-drag ratio ("L/D" or just "LD"), which can
be anything from 20:1 for some older designs such as the SGS 1-26, right
through to 60:1 for the latest FAI Open Class racing super ships that
can glide 100 km from a typical (around here) 5000 foot cloudbase.
If you think about it, the fuel economy of a powered aircraft is
directly proportional to the L/D ratio. As the airline industry has
become more competitive it's become more and more important to minimize
fuel costs, and that means increasing the L/D ratio. As a result a lot
of current airliners are around the 20:1 mark. That's far better than
your average Cessna.
A quick web search finds at http://www.canard.com/cp/stet/CP28-5.html
numbers showing the Long-EZ to have an L/D ratio of 16.8:1 at 90 knots.
I don't know, but I'd imagine it might be close to 20:1 at somewhere
around 60 - 70 knots. Also, I'm not clear on whether those figures are
with or without power -- the EZ-Rocket gliding doesn't have all the drag
of a windmilling prop that a standard Long-EZ will have.
> I have been following events at ArmadilloAerospace and having throttlable
> engines (of any sort) allows for amazing design flexibility and control.
Armadillo are good guys too :-) So are Pioneer, but they've been rather
quiet lately :-(
-- Bruce
Cameron Dorrough
> In article <ag011m$i58$1...@perki.connect.com.au>,
> "Cameron Dorrough" <cdor...@spamspamgoawayrmna.com.au> wrote:
>
> > I'm guessing that not being able to throttle the engines would restrict
> > airframe design somewhat, since you are forced into a design that can
glide
> > right from the drawing board. If your typical modern airliner had had a
> > design requirement for a better glide-slope than your average
housebrick, we
> > would have skipped Comets, 707's, 727's, DC-9's, DC-10's, the original
747's
> > and many others and only just recently have stopped travelling by ship!
:-)
>
> Actually, many airliners glide very well. The main performance criteria
> for a glider is the lift-to-drag ratio ("L/D" or just "LD"), which can
> be anything from 20:1 for some older designs such as the SGS 1-26, right
> through to 60:1 for the latest FAI Open Class racing super ships that
> can glide 100 km from a typical (around here) 5000 foot cloudbase.
>
> If you think about it, the fuel economy of a powered aircraft is
> directly proportional to the L/D ratio. As the airline industry has
> become more competitive it's become more and more important to minimize
> fuel costs, and that means increasing the L/D ratio. As a result a lot
> of current airliners are around the 20:1 mark. That's far better than
> your average Cessna.
I had thought the improvement in L/D ratio was for *safety* reasons - and
not just fuel economy. Maintaining sufficient forward speed for the control
surfaces to work, whilst still being able to land within the airfame limits,
is one problem. As an example: A fully-loaded orginal Boeing 747 would
practically fall out of the sky if one engine failed, whilst a 747-400
(which is a much heavier aircraft, BTW) will continue to fly quite happily
thanks to better engines and airframe design.
It depends on your definition of "glide quite well", I suppose. I agree
that modern airliners *do* glide pretty well - but the older ones don't have
a very good reputation. IMHO, a dead-stick landing in a Cessna is more of a
controlled crash, and hence my original post.. :-)
> A quick web search finds at http://www.canard.com/cp/stet/CP28-5.html
> numbers showing the Long-EZ to have an L/D ratio of 16.8:1 at 90 knots.
> I don't know, but I'd imagine it might be close to 20:1 at somewhere
> around 60 - 70 knots. Also, I'm not clear on whether those figures are
> with or without power -- the EZ-Rocket gliding doesn't have all the drag
> of a windmilling prop that a standard Long-EZ will have.
Thanks, Bruce. I agree. I'm just not sure that some of the other X-Prize
entrants measure up, tho' ... If you are going to 'dead-stick' land all the
time, you need to maintain your L/D ratio at low speeds *by design* -
meaning larger than optimal wings and control surfaces which adds weight,
drag, etc., etc. To take the other extreme, what's the L/D ratio of a
rocket?? ;-)
If you've got throttlable engines, you get much more control whatever the
L/D ratio... :-)
Geoffrey A. Landis
>
> "Bruce Hoult" <br...@hoult.org> wrote:
>
> > Actually, many airliners glide very well. The main performance criteria
> > for a glider is the lift-to-drag ratio ("L/D" or just "LD"), which can
> > be anything from 20:1 for some older designs such as the SGS 1-26, right
> > through to 60:1 for the latest FAI Open Class racing super ships that
> > can glide 100 km from a typical (around here) 5000 foot cloudbase.
> >
> > If you think about it, the fuel economy of a powered aircraft is
> > directly proportional to the L/D ratio. As the airline industry has
> > become more competitive it's become more and more important to minimize
> > fuel costs, and that means increasing the L/D ratio. As a result a lot
> > of current airliners are around the 20:1 mark. That's far better than
> > your average Cessna.
>
> I had thought the improvement in L/D ratio was for *safety* reasons - and
> not just fuel economy.
No.
If you think about it, at a fixed airspeed, fuel economy is directly
proportional to L/D. An efficient airplane is a high L/D airplane.
747s had high L/D from the first one off the production line, by design.
>...
> It depends on your definition of "glide quite well", I suppose. I agree
> that modern airliners *do* glide pretty well
Actually, they have good glide ratio, but don't really qualify as
gliding "well".
> - but the older ones don't have
> a very good reputation. IMHO, a dead-stick landing in a Cessna is more of a
> controlled crash, and hence my original post.. :-)
An airliner has *much* better L/D than a typical Cessna.
> ...
> Thanks, Bruce. I agree. I'm just not sure that some of the other X-Prize
> entrants measure up, tho' ... If you are going to 'dead-stick' land all the
> time, you need to maintain your L/D ratio at low speeds *by design* -
Actually, for a dead-stick landing, high CL (and controllability at high
CL) is more important than L/D-- L/D itself buys you almost nothing
useful at landing, except to put the runway far ahead of you instead of
under you. Most aircraft have spoilers, and some even parachutes, to
*lower* the L/D at landing.
--
Geoffrey A. Landis
http://www.sff.net/people/geoffrey.landis
Doug Jones
>
> not just fuel economy. Maintaining sufficient forward speed for the control
> surfaces to work, whilst still being able to land within the airfame limits,
> is one problem. As an example: A fully-loaded orginal Boeing 747 would
> practically fall out of the sky if one engine failed, whilst a 747-400
> (which is a much heavier aircraft, BTW) will continue to fly quite happily
> thanks to better engines and airframe design.
Nope. Even older model 747s have L/D of about 16
(http://www.hq.nasa.gov/office/pao/History/SP-468/ch10-2.htm) and one
of them once spent nearly 20 minutes gliding when all engines flamed
out after encountering a volcanic ash cloud
(http://www.nw.faa.gov/releases/volash.html). That 747 maintained
level flight on one engine, thanks to a good power/weight ratio- the
four engines are only needed at full power for takeoff, and are run at
much lower power the rest of the time.
> It depends on your definition of "glide quite well", I suppose. I agree
> that modern airliners *do* glide pretty well - but the older ones don't have
> a very good reputation. IMHO, a dead-stick landing in a Cessna is more of a
> controlled crash, and hence my original post.. :-)
Nope. It's a piece of cake, I've done it myself. I've done almost
100 landings myself on systems with L/D of 3, although the flare has
to be neatly timed.
> > A quick web search finds at http://www.canard.com/cp/stet/CP28-5.html
> > numbers showing the Long-EZ to have an L/D ratio of 16.8:1 at 90 knots.
> > I don't know, but I'd imagine it might be close to 20:1 at somewhere
> > around 60 - 70 knots. Also, I'm not clear on whether those figures are
> > with or without power -- the EZ-Rocket gliding doesn't have all the drag
> > of a windmilling prop that a standard Long-EZ will have.
Actual flight test data from Dick's N169SH indicates an idle-power L/D
of about 12, not 16- that prop really hurts ya. We don't yet have
good enough data on the EZ-Rocket to measure its L/D accurately
because all its flights have been circling descents, which reduce the
measured L/D- but I'm sure its at least 14.
> Thanks, Bruce. I agree. I'm just not sure that some of the other X-Prize
> entrants measure up, tho' ... If you are going to 'dead-stick' land all the
> time, you need to maintain your L/D ratio at low speeds *by design* -
> meaning larger than optimal wings and control surfaces which adds weight,
> drag, etc., etc.
Nope. If the wings are large enough for a horizontal takeoff, they are
more than ample for landing- when the vehicle might weigh less than
1/5th as much. L/D and wing loading are separate issues.
> If you've got throttlable engines, you get much more control whatever the
> L/D ratio... :-)
Step throttling can be more than sufficient- we plan to use four
engines on future vehicles. Throttling a large rocket engine is
expensive, inefficient, and heavy- far better to shut them down when
not needed.
Doug Jones, Rocket Plumber
Jack Sandy
Bruce: I am new to computer discussion groups, and new to the group
discussion at sci.space.tech.
I am seeking feedback on the feasability of launching nuclear waste into
the Sun, from Earth, cheaply. I am considering mag-lev rail launch
vehicles powered by solar energy, as well as space elevators and super
high pressure ballons.
How do I address questions to this Group, or is this appropriate. Do
you know of another group. for whom this subject is more appropriate?
Thanks,
Jack Sandy
Retired Geologist
Indianapolis.
Jake McGuire
> I had thought the improvement in L/D ratio was for *safety* reasons - and
> not just fuel economy. Maintaining sufficient forward speed for the control
> surfaces to work, whilst still being able to land within the airfame limits,
> is one problem.
You are confusing L/D with wing loading. Wing loading is how many
pounds of airplane each square foot of wing has to support, or how
fast the wing has to be moving to stay aloft. L/D is how hard you
have to push on the wing to get a pound of lift, which determines how
big your engines have to be and/or how steeply you have to glide.
Large complicated flaps on airliners make L/D dramatically *worse*,
but reduce the wing loading enough to permit reasonable landing speeds
with a wing small enough for efficient cruise.
> If you are going to 'dead-stick' land all the time, you need to maintain your
> L/D ratio at low speeds *by design* - meaning larger than optimal wings and
> control surfaces which adds weight, drag, etc., etc.
Again, low speed landings require a low wing loading, not a high L/D.
As long as the L/D is reasonable, that is. I think once you get below
around 4 or 5 you start to run into problems being able to get the
flare right.
-jake
Cameron Dorrough
news:cf60b6ee.02070...@posting.google.com...
> "Cameron Dorrough" <cdor...@spamspamgoawayrmna.com.au> wrote
> >
> > I had thought the improvement in L/D ratio was for *safety* reasons -
and
> > not just fuel economy. Maintaining sufficient forward speed for the
control
> > surfaces to work, whilst still being able to land within the airfame
limits,
> > is one problem. As an example: A fully-loaded orginal Boeing 747 would
> > practically fall out of the sky if one engine failed, whilst a 747-400
> > (which is a much heavier aircraft, BTW) will continue to fly quite
happily
> > thanks to better engines and airframe design.
>
> Nope. Even older model 747s have L/D of about 16
> (http://www.hq.nasa.gov/office/pao/History/SP-468/ch10-2.htm) and one
> of them once spent nearly 20 minutes gliding when all engines flamed
> out after encountering a volcanic ash cloud
> (http://www.nw.faa.gov/releases/volash.html). That 747 maintained
> level flight on one engine, thanks to a good power/weight ratio- the
> four engines are only needed at full power for takeoff, and are run at
> much lower power the rest of the time.
I stand corrected. I rechecked my sources last night to discover that major
improvements were takeoff thrust, due to better engines, and a stronger
airframe and was nothing to do with glide.. As you mention, the 747-100
needs all four engines on takeoff whereas a 747-400 needs only one or at the
most two to maintain climb (just).. you can also barrell-roll a '400 but it
is not recommended (it freaks people out! ;-)
> > It depends on your definition of "glide quite well", I suppose. I agree
> > that modern airliners *do* glide pretty well - but the older ones don't
have
>
> > a very good reputation. IMHO, a dead-stick landing in a Cessna is more
of
> > a controlled crash, and hence my original post.. :-)
>
> Nope. It's a piece of cake, I've done it myself. I've done almost
> 100 landings myself on systems with L/D of 3, although the flare has
> to be neatly timed.
Okay... I'll stick to gliders! (model ones! :-)
Thanks, Doug. That answers my original question. Would you still
dead-stick land in this configuration? Or would you land on one engine for
safety??
Cameron:-)
>
> Doug Jones, Rocket Plumber
>
Bruce Hoult
djo...@xcor.com (Doug Jones) wrote:
> > It depends on your definition of "glide quite well", I suppose. I agree
> > that modern airliners *do* glide pretty well - but the older ones don't have
>
> > a very good reputation. IMHO, a dead-stick landing in a Cessna is more of a
> > controlled crash, and hence my original post.. :-)
>
> Nope. It's a piece of cake, I've done it myself. I've done almost
> 100 landings myself on systems with L/D of 3, although the flare has
> to be neatly timed.
Since most people don't have access to the STS, was that on helicopters?
I've noticed that both the Robinson R22 and the Bell 212 "Huey", despite
their quite difference sizes, autorotate best at around 60 knots forward
speed and 2000 fpm down -- which is near enough to 3:1. Jet fighters
are another possibility. Somewhere around here I've got a QuickTime
movie of an F-16 doing a dead-stick landing. Most of the time the HUD
is showing about a 17 degree flight path. That's a 3.4:1 L/D.
I've got ... uh ... 270 landings in gliders. Certification requirements
are that a glider should have an L/D of no more than 7 with full
airbrakes at normal no-wind approach speed (Vso + 10 knots) and many
have much more powerful brakes/spoilers/flaps than that. I've flown
several gliders in which you can approach in a 45 degree dive with full
brakes, and by the time you've flared you're down to touchdown speed.
That's an L/D of 1.
> > > A quick web search finds at http://www.canard.com/cp/stet/CP28-5.html
> > > numbers showing the Long-EZ to have an L/D ratio of 16.8:1 at 90 knots.
> > > I don't know, but I'd imagine it might be close to 20:1 at somewhere
> > > around 60 - 70 knots. Also, I'm not clear on whether those figures are
> > > with or without power -- the EZ-Rocket gliding doesn't have all the drag
> > > of a windmilling prop that a standard Long-EZ will have.
>
> Actual flight test data from Dick's N169SH indicates an idle-power L/D
> of about 12, not 16- that prop really hurts ya. We don't yet have
> good enough data on the EZ-Rocket to measure its L/D accurately
> because all its flights have been circling descents, which reduce the
> measured L/D- but I'm sure its at least 14.
I suspected as much ... that 16.8 L/D will be at cruise power, with the
engine supplying the thrust needed to overcome drag, rather than with
the prop windmilling and adding drag. i.e. what that web page is saying
is that in a 90 knot cruise, the thrust needed from the prop/engine is
weight/16.8.
> > Thanks, Bruce. I agree. I'm just not sure that some of the other X-Prize
> > entrants measure up, tho' ... If you are going to 'dead-stick' land all the
> > time, you need to maintain your L/D ratio at low speeds *by design* -
> > meaning larger than optimal wings and control surfaces which adds weight,
> > drag, etc., etc.
>
> Nope. If the wings are large enough for a horizontal takeoff, they are
> more than ample for landing- when the vehicle might weigh less than
> 1/5th as much. L/D and wing loading are separate issues.
In fact they're pretty much totally independent. I know of gliders that
weigh 200 kg empty and are frequently ballasted with 200 kg of water in
the wings. The best L/D remains the same, it just happens at a higher
speed (sqrt of the weight ratio higher).
-- Bruce
Jake McGuire
> Step throttling can be more than sufficient- we plan to use four
> engines on future vehicles. Throttling a large rocket engine is
> expensive, inefficient, and heavy- far better to shut them down when
> not needed.
Really? I can understand inefficient (sort of - turbines are
notoriously bad off-design performers, but there are other ways to
pump), I can kind of understand expensive (I know how Jeff hates
computerized controls), but I don't see where the heavy comes from.
Doesn't the thrust chamber generally weigh a lot more than the various
controls and such, and isn't the thrust chamber weight largely
independent of throttleability?
-jake
Peter Smith
Doug Jones <djo...@xcor.com> wrote...
> Step throttling can be more than sufficient- we plan to use four
> engines on future vehicles. Throttling a large rocket engine is
> expensive, inefficient, and heavy- far better to shut them down
> when not needed.
With four on/off engines, it would be possible to have 16 "thrust
states" if the thrust of each engine is double the next engine.
Although that could create some vector asymmetry and increase production
cost over 4 identical engines.
- Peter
Damon Hill
news:29102-3D2...@storefull-2237.public.lawson.webtv.net
> I am seeking feedback on the feasability of launching
> nuclear waste into the Sun, from Earth, cheaply. I am
> considering mag-lev rail launch vehicles powered by solar
> energy, as well as space elevators and super high pressure
> ballons.
>
Disposal of waste into the sun appears impractical. The amount
of energy required to dump thousands of tons of material is
beyond our technological capability. We'd have enough trouble
getting it into low orbit, let alone the massive velocity
changes to slow it down into a sun-intersecting trajectory.
That's why there has only been one probe launched to Mercury.
--Damon
B. Isaksen
> I am seeking feedback on the feasability of launching nuclear waste into
> the Sun, from Earth, cheaply. I am considering mag-lev rail launch
> vehicles powered by solar energy, as well as space elevators and super
> high pressure ballons.
First. Are you mad(?), the current success rate of "rockets" are 0.95,
that meens that 1 of 20 is not behaving as it should.
Ok, sometime the launchers will be reliable enough, but we are not
there quite yet.
2. Mag-lev keeps comming up in this group regulary, there are many
problems with this design, i recomand that you google a little and
come back to this when you have some solutions to the mechanical,
aerodymanic and constrution problems.
3. Same is true for elevators, problems (eg. windshear).
4. Ballons can get you up but not give you the speed you need (the US
Shuttle uses about 7% of the fuel for the lifting part, the rest is
kinetic energy).
> How do I address questions to this Group, or is this appropriate. Do
> you know of another group. for whom this subject is more appropriate?
You'we allready adressed your question, and yes this is a propriate
group.
> Jack Sandy
> Retired Geologist
> Indianapolis.
Bjørn Ove
Petroleum Engineer
Henry Spencer
Damon Hill <damo...@attbi.com> wrote:
>Disposal of waste into the sun appears impractical. The amount
>of energy required to dump thousands of tons of material is
>beyond our technological capability.
Uh, no -- that's ridiculous. Speaking roughly, to drop stuff into the
Sun, you have to kill Earth's orbital velocity, about 30km/s. That
requires a kinetic energy (neglecting the requirement to leave Earth's
gravity, which is pretty minor by comparison) of 450MJ/kg. While that's
quite a bit, it is far from "beyond our technological capability".
Figuring a single large powerplant as 3GW, that's 576 tons/day dropped
into the Sun. Of course, the launch process won't be 100% efficient; if
we figure an overall efficiency of 5%, however -- not grossly implausible
for a laser launcher or electromagnetic catapult -- that single plant
still ships 10,000t a year into the Sun.
It is, of course, possible to build multiple powerplants.
>We'd have enough trouble getting it into low orbit,
>let alone the massive velocity
>changes to slow it down into a sun-intersecting trajectory.
>That's why there has only been one probe launched to Mercury.
You're confusing what could be done with *existing systems*, with what
could be done if we decided we really wanted to ship thousands of tons per
year into the Sun. The gap between what we are technologically capable of
doing and what we have actually felt like doing to date is particularly
large for spaceflight.
--
Socialists always tell us they're going to | Henry Spencer
do better next time. -- Ed Wright | he...@spsystems.net
Ian Stirling
>
> May...@webtv.net (Jack Sandy) wrote in message news:<29102-3D2B1002-821@storeful
> l-2237.public.lawson.webtv.net>...
>
>> I am seeking feedback on the feasability of launching nuclear waste into
>> the Sun, from Earth, cheaply. I am considering mag-lev rail launch
>> vehicles powered by solar energy, as well as space elevators and super
>> high pressure ballons.
>
> First. Are you mad(?), the current success rate of "rockets" are 0.95,
> that meens that 1 of 20 is not behaving as it should.
> Ok, sometime the launchers will be reliable enough, but we are not
> there quite yet.
Current 'best of breed' rockets are at about 0.995 or better.
<snip>
> 3. Same is true for elevators, problems (eg. windshear).
An elevator is a structure generally designed for a lifetime of decades,
and takes into account windshear and other problems.
My take on this is that you either store it someplace on the
surface, safely, or stick it in a subduction zone.
--
http://inquisitor.i.am/ | mailto:inqui...@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
What a wonderfull world it is that has girls in it! -- Robert A Heinlein.
Damon Hill
news:Gz55r...@spsystems.net:
>
> You're confusing what could be done with *existing
> systems*, with what could be done if we decided we really
> wanted to ship thousands of tons per year into the Sun.
> The gap between what we are technologically capable of
> doing and what we have actually felt like doing to date is
> particularly large for spaceflight.
And I still think that's wildly optimistic.
--Damon, who'd be delighted to see it made possible
B. Isaksen
> > that meens that 1 of 20 is not behaving as it should.
> > Ok, sometime the launchers will be reliable enough, but we are not
> > there quite yet.
>
>
> Current 'best of breed' rockets are at about 0.995 or better.
A few launchers havent failed yet, and a few have failed a lot of
times. Your figure of 0.995 is intresting, and I'm a little surprised
that you have such numbers. As you know you would propably have
launched a thousand times to get this number with reasonably accuracy
from empiric data. The other way of getting this number is from
integration of every subsustems failrate and the known uncertanties in
the enviromental factors (high wind in the upper parts of the
atmosphere, debris ect.).
Have you got a URL for this calulations?
Still. Will you launch uranium with a fairate of 1:200?
> > 3. Same is true for elevators, problems (eg. windshear).
>
> An elevator is a structure generally designed for a lifetime of decades,
> and takes into account windshear and other problems.
There are some consepts, true. They all depend on technologies not
presently exsistent (as large quanta carbon-carbon technologies).
So in my opinion the problems have not been taken into account *yet*.
> My take on this is that you either store it someplace on the
> surface, safely, or stick it in a subduction zone.
Agree!
Bjørn Ove.
Paul Blay
> Current 'best of breed' rockets are at about 0.995 or better.
Can't use either Shuttle or Soyuz for earth escape missions.
I'd be interested to know what other launch vehicle can claim
'0.995 or better'
Joann Evans
Well, *once* you get it to LEO (first you catch a rabbit...), low
thrust engines of one sort or another can get it slowly away from here
(though you might not want electronics exposed to VanAllen belt
radiation [I assume it's already shielded from the waste itself] any
longer than necessary by spiraling out too slowly), and, orbital
mechanice permitting, sent it toward Jupiter where it could then be
slingshotted to solar escape, or 'reverse' slingshotted toward the Sun.
It would be more energy efficent then trying to drop it into the Sun
directly from here, but I don't claim to know if it would also be
economical....
Ian Stirling
>
>> > First. Are you mad(?), the current success rate of "rockets" are 0.95,
>> > that meens that 1 of 20 is not behaving as it should.
>> > Ok, sometime the launchers will be reliable enough, but we are not
>> > there quite yet.
>>
>>
>> Current 'best of breed' rockets are at about 0.995 or better.
>
> A few launchers havent failed yet, and a few have failed a lot of
> times. Your figure of 0.995 is intresting, and I'm a little surprised
> that you have such numbers. As you know you would propably have
> launched a thousand times to get this number with reasonably accuracy
> from empiric data. The other way of getting this number is from
The 0.995 figure was pulled from the air, as I know that some
rockets are at least at their several hundredth launch without incident.
0.95 is far too low, even the shuttle beats that.
<snip>
> Still. Will you launch uranium with a fairate of 1:200?
Only if it's in a reactor, or pulsed power units.
Launching waste on rockets is pretty much insane.
>> > 3. Same is true for elevators, problems (eg. windshear).
>>
>> An elevator is a structure generally designed for a lifetime of decades,
>> and takes into account windshear and other problems.
>
> There are some consepts, true. They all depend on technologies not
> presently exsistent (as large quanta carbon-carbon technologies).
> So in my opinion the problems have not been taken into account *yet*.
The technology needed is indeed beyond us right now.
But, we can make nanotubes 1um long now, (I have not kept up with research,
it's probably much larger), once we cah make them in bulk in milimeter
lengths, then things may be very different.
>> My take on this is that you either store it someplace on the
>> surface, safely, or stick it in a subduction zone.
>
> Agree!
--
http://inquisitor.i.am/ | mailto:inqui...@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
The fight between good and evil, an epic battle. Darth vader and Luke,
suddenly in the middle of the fight, Darth pulls Luke to him, and whispers
"I know what you'r getting for christmas!" Luke exclaims "But how ??!?"
"It's true Luke, I know what you'r getting for christmas" Luke tries to ignore
this, but wrenches himself free, yelling "How could you know this?",
Vader replies "I felt your presents" -- The Chris Evans breakfast show ca. 94
Jan C. Vorbrüggen
> but reduce the wing loading enough to permit reasonable landing speeds
> with a wing small enough for efficient cruise.
..and your engines running at higher thrust so that you actually get
a chance to do a turnaround when you need it, instead of having to wait
too long for them to rev up...
Jan
sanman
> The engines cannot be throttled back and the thrust of
> just one rocket engine is roughly the same as the
> standard EZ piston engine at full power.
I notice that the fuel tank at the bottom of EZ-rocket barely has
clearance over the ground. Hope that landing gear is solid, otherwise
a hard touchdown could see that tank contacting the ground.
I know the EZ-rocket is a technology demonstrator. Are there any plans
to scale it upto something bigger, for even higher sub-orbital
flights, and perhaps one day, orbital?
Henry Spencer
sanman <mano...@yahoo.com> wrote:
>I know the EZ-rocket is a technology demonstrator. Are there any plans
>to scale it upto something bigger, for even higher sub-orbital
>flights, and perhaps one day, orbital?
XCOR certainly has interests in that direction, although it would be done
with a custom design, not with an EZ-rocket derivative. (The EZ-rocket
aircraft just happened to be handy -- it is totally unsuited to anything
beyond low-speed engine testing.)
They are (understandably) not very talkative about details yet.
Geoffrey A. Landis
>
> The 0.995 figure was pulled from the air, as I know that some
> rockets are at least at their several hundredth launch without incident.
Depends on how you count. If your count is "total number of launch
failures divided by total number of launches", then no, no booster makes
99.5%. Shuttle is the most reliable of the existing family, at 99.1%.
Soyuz, I believe, is number two at slightly over 97%
If, however, you are willing to shorten the record to just the last n
launches, then some boosters might make it. Soyuz, for example: I don't
think that they've lost one recently.
The source is _International Reference Guide to Space Launch Systems_,
third edition, which has a complete tally of launch failures (the
edition I have is the 2nd, 1995, so I don't have the most up to date numbers)
Jim Kingdon
> done with a custom design, not with an EZ-rocket derivative. (The
> EZ-rocket aircraft just happened to be handy -- it is totally unsuited
> to anything beyond low-speed engine testing.)
Yup. The http://www.xcor.com/suborbital.html web page talks a bit
about the market.
> They are (understandably) not very talkative about details yet.
The same web page discusses their lack of talkativeness. Apparently
they are planning on keeping it that way.
Pat Flannery
Henry Spencer wrote:
>
>XCOR certainly has interests in that direction, although it would be done
>with a custom design, not with an EZ-rocket derivative. (The EZ-rocket
>aircraft just happened to be handy -- it is totally unsuited to anything
>beyond low-speed engine testing.)
>
....Except for looking Way,Way, COOL; especially with that twin barrel
rocket revved up at night- about the sort of thing you would be
expecting to be rising out of Stuttgart to intercept the incoming
Northrop B-35 flying wings around May, 1946....now let's see...how many
R4M's can we hang under the wings? Can the wing and canard be reinforced
so it can ram things? Can skids replace the wheels? If we put solid
fueled boosters on it- can we launch it vertically up the side of a
telephone pole?
From the secret Antarctic base-
Pat
Michael Walsh
Pat Flannery wrote:
I believe that if Dick Rutan really wanted to commit suicide he could
do it by running the rocket engines on the current EZ rocket
aircraft flat out for the full duration of the onboard propellant.
Someone correct me if I am wrong, I don't have detailed
knowledge of the capabilities of the EZ.
Mike Walsh
Rand Simberg
Walsh <mp1w...@Adelphia.net> made the phosphor on my monitor glow in
such a way as to indicate that:
>I believe that if Dick Rutan really wanted to commit suicide he could
>do it by running the rocket engines on the current EZ rocket
>aircraft flat out for the full duration of the onboard propellant.
>
>Someone correct me if I am wrong, I don't have detailed
>knowledge of the capabilities of the EZ.
I don't think that would be a problem with the current propellant
load, as long as he had enough climb angle, but I could be wrong, too.
--
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Jeff Greason
> Someone correct me if I am wrong, I don't have detailed
> knowledge of the capabilities of the EZ.
>
Certainly the rockets have more than enough energy
and acceleration to exceed the maximum safe speed
of the aircraft in level flight. Since the EZ-Rocket,
by design, has thrust substantially less than weight,
the pilot can manage the speed, even under full power,
by adjusting the climb angle.
That's why EZ-Rocket flights always have a climbing
phase -- that keeps us from building up too much
velocity.
----------------------------------------------------------------
"Limited funds are a blessing, not Jeff Greason
a curse. Nothing encourages creative President & Eng. Mgr.
thinking in quite the same way." --L. Yau XCOR Aerospace
<www.xcor.com> <jgre...@xcor.com>
Michael Walsh
Jeff Greason wrote:
Thank you. I appreciate the information. I never doubted
that (obviously) Dick Rutan could fly the EZ-Rocket safely, but
I hadn't given much thought to managing the speed by
adjusting the climb angle.
Mike Walsh