Spinlaunch... Can it succeed?

[CatalinaWOW]

The term confined space is where the argument lies.  Cannon barrel must be transportable which constrains their length.  As far as I know the longest cannon ever was a German WWII one of its kind, intend to hit GB from occupied France.  Couldn't be relocated, only a limited traverse and was bombed out of existence before firing a shot.

There are physical limits on a spinning launcher but they are different.  If you are willing to build a really large vacuum chamber you can make the arm long enough to greatly reduce radial acceleration.   

I don't think spin launch is a particularly good idea, but there is no equivalence between the accelerations in a cannon and the spin launcher.

[Rick Law]

you need the same energy as in a cannon but a lower peak power.

I guess the whole idea is to not use chemical power (as in rocket fuel) but to use electrical power (which might be next to free one day and does not pollute the environment).
Still, my bet is on "not going to work", even if millions/billions more are spent.

(Bold added)

Actually, SpinLaunch is not avoiding chemical rocket altogether.  Their target is to make ONLY stage 1 "without chemical fuel".  The launch vehicle will launch at 5000mph (mach 10) taking it up to a relatively high altitude, then use chemical rocket to take it the rest of the way.

Earth's escape velocity is about 25000mph (air drag not included), so they are no where near orbital with merely 5000mph.

---------------------

If electrical launch is the goal, rail-gun is a comparatively "easier" solution.  It has been discussed in earlier replies quoted below.  There are other advantages with the G-force.  (see my calculation shown in the quoted reply) For the same exit velocity and same dimension (100 meter diameter spinner vs 100 meter linear gun), the G force for the linear gun is merely 1/4 of the G force for the spinning solution.  The other advantage is that the G force for the rail gun is along the direction of travel and same along the entire base of the payload capsule; whereas, for the spinning wheel, the G force is perpendicular to the direction of travel and varies laterally (left side and right side has different G resulting in compression force between left and right side of the payload capsule).

...
Regarding rail guns. Rail guns don't work, at least not practically, and even the US military is on the verge of totally giving up on that technology.

Rail gun has a demonstrated velocity of around mach 7 by the US Navy.  Mach 7 is around 2.3km/s and is around Spinlauch's planned launch speed.  So while rail gun may not be suitable to be carried around by ships yet, it is certainly feasible for a fix-located rail gun to get to mach 7 exit velocity.

Rail-gun space launch has been proposed by NASA - mach 10 launch speed of a scram jet to complete the journey into low orbit space. 

Spinlaunch is proposing a 100 meter spinning diameter, so we use 100 meter rail gun as base comparison.   Remember the equation I posted in an earlier reply: linear acceleration is V²/2L whereas centrifugal acceleration is V²/R.  R is 1/2 the diameter, so 100 meter linear will have 1/4 the linear g verses spinning centrifugal G.

A much longer rail gun will reduce acceleration G force as well as decrease the power needed for acceleration.  Power is proportional to square of current, so a 10x increase in rail gun length will reduce electrical current need by 100.  10x that length to a 1km rail.  1km rail reduces electrical current need down to 1/100 that of a 100 meter rail.    With 1km rail, the G force is down to 1/40 of centrifugal G of a 100 meter diameter spinner.

But, as already pointed out by mfro's reply, mach 7 is less than 1/3 the escape velocity.  Add air drag to that equation, and air drag is proportional to the square of velocity, I am doubtful that an object with exit velocity at mach 7 can even reach 29,000 feet (height of Everest where air is too thin for human).  1/40 of 10000g (=250g) is still a lot of g's, and we are still talking only mach 7.  So problems are aplenty to actually get it into orbit, spinning or linear.

Reference:
Navy rail gun mach 7 demo video:

[3roomlab]

i saw an interesting article
rocket sled launch system (1969)

[SiliconWizard]

Me too: https://www.ancient-origins.net/artifacts-ancient-technology/were-catapults-secret-roman-military-success-007816