In a message dated 9/15/2018 4:00:07 PM Pacific Standard Time, wikkit@xxxxxxxxx
writes:
(old thread, but I think it's important)
crogers168 said:>It just would have been a lot better to have an altitude for
the prize of 100K>ft or 200K ft. How high has an amateur or university liquid
rocket flown? A>100K ft prize, with a lower prize amount, would have had
multiple competitors.>Per an ARocket thread from some years ago, designing a
prize like the CATS>Prize, the XPrize or the Lunar XPrize, is a difficult
endeavor.>>With the lower altitude you could use a max possible range/max
probable range>approach, and avoided needing an FTS.>>The prize rules state
that the team needs to get a Class 3 waiver for the>rocket, which means FAA
approval, and FAA approval for the FTS.
If by "FTS" you mean the classical sense of an independentradio-actuated flight
termination system, there is no need for thatkind of FTS on a 100km Class 3
amateur rocket, guided or not.
Wow! A response to a post I made 3 months ago! Is that some kind of record?
:)
Actually I welcome the further discussion.
An FTS is not needed on a Class 3 rocket per se. But you will need FAA
approval for the Class 3 rocket, and I believe based on the likely dispersion,
the FAA will require an FTS. But that's up to the FAA, or the Range. And the
"FTS" is one of the various options detailed in later posts.
Class 3 rockets are flown within airspace defined by the FAA where either:
1) A non-spinning rocket physically cannot exceed the boundaries of the
airspace.
2) A dispersion analysis for a non-spinning rocket shows within a certain sigma
that the rocket is unlikely/very unlikely to exceed the boundaries of the
airspace.
3) A dispersion analysis for a spinning rocket (greatly reduced dispersion)
shows that within a certain sigma that the rocket is unlikely/very unlikely to
exceed the boundaries of the airspace.
4) If you are on a Range (not just the typical BLM land out West), the Range
wants to be sure that it is unlikely/very unlikely that your rocket will exceed
the Range boundaries.
Again, as for what kind of "FTS", see the descriptions of the various FTS
options used on other programs described in later posts.
But the FAA, or the Range, will have to approve the FTS that you will be using.
Suppose it is a radio signal cut-off from the ground, cutting engine thrust on
a liquid. Or an onboard system sensing vehicle state that will cut the liquid
rocket engine. The FAA or the Range will need to be really, really convinced
that the system is going to work.
My point really was setting the altitude for the prize at 100K, or 200K ft,
would allow you to use the max probable range approach (for 100K ft), or the
spinning rocket approach (for 200K ft). No FTS required. A low thrust guided
liquid rocket to 100 KM, I think it is likely the FAA will require an FTS of
some kind.
Charles E. (Chuck) Rogers