On Thu, 05 Jun 2003 04:28:32 +0100, Ian Woollard
<[EMAIL PROTECTED]> wrote:
>>You need to demonstrate EC < 30E-6 for every flight.
>>
>Does this mean that from a regulatory standpoint small vehicles have a
>somewhat easier time; since less mass == [presumably] less chance of
>casualties per la
Randall Clague wrote:
You need to demonstrate EC < 30E-6 for every flight.
Does this mean that from a regulatory standpoint small vehicles have a
somewhat easier time; since less mass == [presumably] less chance of
casualties per launch, even if that means you launch more often to
launch the
On Sat, 31 May 2003 10:17:01 -0700 (PDT), Adrian Tymes
<[EMAIL PROTECTED]> wrote:
>> >if you can
>> >demonstrate that P(X_fail) and P(Y_fail) are each
>> at
>> >most 1E-3 (say, run 1000 test flights in which
>> neither
>> >X nor Y fail)
>>
>> You need 2998 flights to demonstrate that with 95%
>>
Adrian Tymes wrote:
--- Randall Clague <[EMAIL PROTECTED]> wrote:
You need 2998 flights to demonstrate that with 95%
confidence.
Eh? 1000 runs where X does not fail, therefore
P(X_fail) < 1/1000. Ditto Y. These just happen to be
the same 1000 runs.
No. Let's say you'v
--- Randall Clague <[EMAIL PROTECTED]> wrote:
> On Fri, 30 May 2003 14:19:33 -0700 (PDT), Adrian
> Tymes
> <[EMAIL PROTECTED]> wrote:
> >In order to have a catastrophic explosion, you
> could
> >design a system so that failures X and Y both have
> to
> >happen.
>
> Oddly phrased - sounds like you
You know, it'd be GREAT to have these kind of engineering problems. But we don't.
We're currently working on acquiring H2O2 so we can fly monopropellant amateur
rockets. Let's focus on that for a while. It's fun to talk, but I end up marking
entire threads as read because they don't actually con
On Sat, 31 May 2003 03:55:43 +0100, Ian Woollard
<[EMAIL PROTECTED]> wrote:
>There is a probability argument; about whether the panels can blow out
>when you don't want them to.
Well, kind of. Yes, there is a probability argument. To be credible,
it must be based on an engineering analysis. T
Randall Clague wrote:
You put blowout panels in your tanks. You need a mechanism to blow
them out in an emergency. But you need to be damn sure they don't
blow out at any other time, or it will BE an emergency. The
damn-sure-they-don't has to have many times the reliability of the
damn-sure-the
On Fri, 30 May 2003 14:19:33 -0700 (PDT), Adrian Tymes
<[EMAIL PROTECTED]> wrote:
>In order to have a catastrophic explosion, you could
>design a system so that failures X and Y both have to
>happen.
Oddly phrased - sounds like you want to have a catastrophic
explosion...but that objection is tri
On Fri, 30 May 2003, John Carmack wrote:
> >Please. What's the most you've ever taken whole body?
>
> Take a perfect, flat-on-your-back judo throw from shoulder height.
And miss your breakfall, of course. (The breakfall makes it hurt less,
at least... My, that brings back memories. Ouch.)
>
On Fri, 30 May 2003, Randall Clague wrote:
> ...Impact speed was
> about 25 mph, and it stove in my grille about a foot. That's 21 g,
> and I was wearing my seat/chest belt. Good thing, or I'd have hit the
> steering column with my sternum. As it was, it HURT. My ribs ached
> for days...
Volvo
--- Randall Clague <[EMAIL PROTECTED]> wrote:
> You put blowout panels in your tanks. You need a
> mechanism to blow
> them out in an emergency. But you need to be damn
> sure they don't
> blow out at any other time, or it will BE an
> emergency. The
> damn-sure-they-don't has to have many times
On Fri, 30 May 2003 09:23:49 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
>2) You walked away -- we're not talking about something you do every flight
>-- just something that happens when the alternative is dying.
Drove away, actually, in a $2500 car that took $6000 worth of damage -
Hondas
At 12:29 AM 5/30/2003 -0700, Randall Clague wrote:
If you were doing 20 mph and you stopped in half a meter, you took 8
g.
Actually, more like 10, but I made a units booboo.
I hit a Buick on the Bay Bridge once, while I was driving a Honda.
(Don't hit a Buick with a Honda. You won't
At 11:35 AM 5/30/2003 -0400, [EMAIL PROTECTED] wrote:
I don't find it reasonable to expect a SSTO style tank to crush in a
controllable manner. If aluminum, it would require extra thicknes, or some
form of ribs throughout the tank, increasing mass considerably. If
composite, it won't have any uni
I don't find it reasonable to expect a SSTO style tank to crush in a
controllable manner. If aluminum, it would require extra thicknes, or some
form of ribs throughout the tank, increasing mass considerably. If
composite, it won't have any uniformity to the crushing whatsoever -
it will simply s
Although, the body can withstand stronger negative G's for a shorter
time period than somewhat weaker G's for a longer interval. Also,
that 1-2 m crush depth doesn't bring them to a full stop, as would be
the case for a ground landing. The end-all requirement is that the
peak G's weighed with the
>50 gees or higher peak acceleration is not unreasonable.
Please. What's the most you've ever taken whole body?
Take a perfect, flat-on-your-back judo throw from shoulder height. You hit
the mat at 6 m/s. You have less than 0.05 m of mat. Assuming linear
deceleration, that would be 0.017 se
On Fri, 30 May 2003 00:16:30 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
>> >50 gees or higher peak acceleration is not unreasonable.
>>
>>Please. What's the most you've ever taken whole body?
>
> I hit a tree doing somewhere between 20 and 30 mph (not sure, I
>was asleep at the tim
At 11:27 PM 5/29/2003 -0700, Randall Clague wrote:
On Thu, 29 May 2003 23:01:55 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
> Fireproof suits, full restraints, acceleration couches, and crash
>cages seem to be perfectly reasonable additions to a man-rated cabin system.
(snort)
You *kn
On Thu, 29 May 2003 23:01:55 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
> Fireproof suits, full restraints, acceleration couches, and crash
>cages seem to be perfectly reasonable additions to a man-rated cabin system.
(snort)
You *know* how hard SSTO is - and still you want to put
On Thu, 29 May 2003 23:03:27 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
> When I think of appropriate emergency dump mechanisms, I think of
>blow-out panels in the tanks that open a hole with a cross section of a
>significant portion of a square meter in the side of the tank. The
On Thu, 29 May 2003 22:50:43 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
> Crash testing isn't that bad, since all you really need to drop is
>a tank, thrust frame, and an aeroshell -- you don't need to put any of the
>expensive engines, avionics, or TPS aboard the crash test dummie
At 03:26 PM 5/29/2003 -0700, Randall Clague wrote:
On Thu, 29 May 2003 00:30:39 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
>It shouldn't be that hard if you can clear all the propellant from the
>tanks before impact.
You have time to dump all the propellants, but you don't have time to
get th
At 03:26 PM 5/29/2003 -0700, Randall Clague wrote:
If you put the passengers in fireproof suits, five point harnesses,
and heavy crash cages, hit the deck at a shallow angle every time, and
don't mind losing your passengers and crew every couple hundred
flights (at least one NASCAR driver dies on
At 03:26 PM 5/29/2003 -0700, Randall Clague wrote:
On Thu, 29 May 2003 09:59:23 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
> A man-rated SSTO is quite a sizeable vehicle -- if the tanks are
>designed to crush properly and the crew cabin is on top, you will have at
>least 10m through w
On Thu, 29 May 2003 18:58:59 -0700 (PDT), Adrian Tymes
<[EMAIL PROTECTED]> wrote:
>Depends. If the choice is between certain death by
>massive abrupt deceleration, versus potential or even
>probably injury or death by not-so-massive abrupt
>deceleration and the chance of winding up in a flaming
>
--- Randall Clague <[EMAIL PROTECTED]> wrote:
> Do you really want to dump unburned rocket
> propellants onto a piece of
> ground you're about to crash-land on?
Depends. If the choice is between certain death by
massive abrupt deceleration, versus potential or even
probably injury or death by not
On Thu, 29 May 2003 17:11:22 -0700 (PDT), Adrian Tymes
<[EMAIL PROTECTED]> wrote:
>Not a matter of time. A matter of "main exhaust
>mechanism - the engine - plugged or otherwise
>unusable, so use backup". Then again, if the engines
>are out anyway, perhaps you could get some thrust to
>counter g
--- Randall Clague <[EMAIL PROTECTED]> wrote:
> On Thu, 29 May 2003 00:30:39 -0700, Pierce Nichols
> <[EMAIL PROTECTED]> wrote:
> >It shouldn't be that hard if you can clear all the
> propellant from the
> >tanks before impact.
>
> You have time to dump all the propellants, but you
> don't have t
On 29 May 2003 16:06:53 -0700, "Sean R. Lynch" <[EMAIL PROTECTED]>
wrote:
>A head on collision with a barrier that absorbs a negligible amount of
>energy (i.e. a concrete wall that does not collapse or move) is
>equivalent to a head on collision between two cars of equivalent mass at
>*the same sp
On 29 May 2003 15:51:54 -0700, David Masten <[EMAIL PROTECTED]>
wrote:
>> Rather than design a vehicle that crashes safely, why not design one
>> that doesn't crash?
>
>I have never seen such a beast, and I suspect that it can not exist, in
>fact, I'd give better odds for the existence of pink uni
On Thu, 2003-05-29 at 15:26, Randall Clague wrote:
> Moderate being about 35 mph into a fixed barrier, which is the median
> crash speed in this country. You're talking about 220 mph, just under
> 40x the energy, into a fixed barrier - not survivable - or a head on
> collision with both cars doing
On Thu, 2003-05-29 at 15:26, Randall Clague wrote:
> Rather than design a vehicle that crashes safely, why not design one
> that doesn't crash?
I have never seen such a beast, and I suspect that it can not exist, in
fact, I'd give better odds for the existence of pink unicorns.
Considering how to
On 29 May 2003 10:30:22 -0700, David Masten <[EMAIL PROTECTED]>
wrote:
>Modern automobiles are tested in straight-on collisions at moderate
>speeds and designed to keep the driver and passenger alive.
Moderate being about 35 mph into a fixed barrier, which is the median
crash speed in this countr
On Thu, 29 May 2003 00:30:39 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
>It shouldn't be that hard if you can clear all the propellant from the
>tanks before impact.
You have time to dump all the propellants, but you don't have time to
get the engines lit?
-R
-- "We've all heard that a m
On 29 May 2003 00:05:08 -0700, David Masten <[EMAIL PROTECTED]>
wrote:
>Having watched the Indy 500 this past weekend including the occasional
>220+ mph (100+ m/s) crash, and then also considering the area to unit
>mass of SSTO vehicles and thus its terminal velocity (quick back of the
>envelope s
On Thu, 29 May 2003 09:59:23 -0700, Pierce Nichols
<[EMAIL PROTECTED]> wrote:
> A man-rated SSTO is quite a sizeable vehicle -- if the tanks are
>designed to crush properly and the crew cabin is on top, you will have at
>least 10m through which to decelerate. IIRC, ppl have take 16 G con
On 29 May 2003, Sean R. Lynch wrote:
> It seems to me that the generally accepted solution to this problem is
> parachutes - either some sort of ejection system for the crew or the
> whole crew cabin, or (probably preferably) for the whole vehicle.
The problem with a whole-vehicle parachute is tha
At 12:14 PM 5/29/2003 -0700, Sean R. Lynch wrote:
On Thu, 2003-05-29 at 09:59, Pierce Nichols wrote:
> A man-rated SSTO is quite a sizeable vehicle -- if the tanks are
> designed to crush properly and the crew cabin is on top, you will have at
> least 10m through which to decelerate. IIRC,
On Thu, 2003-05-29 at 09:59, Pierce Nichols wrote:
> A man-rated SSTO is quite a sizeable vehicle -- if the tanks are
> designed to crush properly and the crew cabin is on top, you will have at
> least 10m through which to decelerate. IIRC, ppl have take 16 G continuos
> on their backs
On Thu, 2003-05-29 at 08:39, [EMAIL PROTECTED] wrote:
> Don't forget the only survivable crashes are at oblique angles to
> the wall, minimizing the negative G's. Any similar crash from the
> air would require no obstacles on the ground, and a similar oblique
> angle to the ground on contact. If
At 05:43 PM 5/29/2003 +0100, Ian Woollard wrote:
Terminal velocity is typically around ~200mph, but depends on the drag
factor. Vertical impact with the ground is not survivable without a
considerable crush zone (for example 10m crush zone from 80m/s gives an
average of 16g for 1/4 of a second,
Pierce Nichols wrote:
Still, it's injured, not dead. Both impact speed and crush
length are likely quite a bit higher than your assumption; however,
this is not a horrible thing. Race car drivers survive going into the
wall at 100 m/s on a fairly regular basis, generally eyeballs out,
On Thu, 29 May 2003 [EMAIL PROTECTED] wrote:
> Don't forget the only survivable crashes are at oblique angles to
> the wall, minimizing the negative G's.
Remember, that's with a crush distance of only 1-2m. Increasing that
distance by an order of magnitude has much the same effect as putting
the
Don't forget the only survivable crashes are at oblique angles to
the wall, minimizing the negative G's. Any similar crash from the
air would require no obstacles on the ground, and a similar oblique
angle to the ground on contact. If you require this, you might as well
put a runway there.
Dan
On Thursday, May 29, 2003, at 11:15 AM, Pierce Nichols wrote:
At 10:37 AM 5/29/2003 -0400, Andrew Case wrote:
Unfortunately peak acceleration is probably substantially more. Also
mean acceleration scales with the square of impact velocity. The good
news is that 44 m/s is already pretty fast, so
At 11:31 AM 5/29/2003 -0400, Henry Spencer wrote:
On 29 May 2003, David Masten wrote:
> Having watched the Indy 500... I am wondering if a VTVL vehicle
> with engine out on (crash) landing can be designed to practically
> disintegrate while the crew/passenger compartment remains intact and the
> pa
On 29 May 2003, David Masten wrote:
> Having watched the Indy 500... I am wondering if a VTVL vehicle
> with engine out on (crash) landing can be designed to practically
> disintegrate while the crew/passenger compartment remains intact and the
> passengers walk away.
You're not the first one to c
At 10:37 AM 5/29/2003 -0400, Andrew Case wrote:
On Thursday, May 29, 2003, at 03:30 AM, Pierce Nichols wrote:
It shouldn't be that hard if you can clear all the propellant from the
tanks before impact. IIRC, Indy Cars use special fuel tanks that impound
the fuel during a crash to limit the poss
On Thursday, May 29, 2003, at 03:30 AM, Pierce Nichols wrote:
It shouldn't be that hard if you can clear all the propellant from the
tanks before impact. IIRC, Indy Cars use special fuel tanks that
impound the fuel during a crash to limit the possibility of fire and
explosion. The tanks and air
It shouldn't be that hard if you can clear all the propellant from the
tanks before impact. IIRC, Indy Cars use special fuel tanks that impound
the fuel during a crash to limit the possibility of fire and explosion. The
tanks and airframe would have to be designed to fail gracefully, like the
c
On Wed, 2003-05-28 at 22:00, [EMAIL PROTECTED] wrote:
> For SSTO, I like the VTVL "flying fuel tanks" that come back with lots of
> area per unit mass. Catastrophic early abort could be handled by a separable
> capsule design that saves the crew/avionics/payload. With clever, creative
> d
On Thu, 29 May 2003 01:00:42 EDT, [EMAIL PROTECTED] wrote:
>My first thought is that, for an orbital vehicle,
>undercarriage strength, and not runway length, will be the main concern in such a
>circumstance. (Randall might say "Splat!" ;-) )
No no. Splat candidates do NOT get to fly these veh
Gentlefolk,
With a GLOW of around 200 tons and a mass ratio of 20+, my feeling is that an
orbital vehicle is an entirely different thing than a fighter or an X-prize
vehicle in the HTHL discussion. If a single vehicle, I don't think you're
wheels up at anything like 70 m/s; the wings to do tha
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