Launch Report - 07/28

Launch Report - 07/28

Post by Mark W. How » Tue, 30 Jul 1996 04:00:00



LAUNCH REPORT  07/28/96 - 5 TOTAL
=================================

                        PREVIOUS   RECOVERY         ENGINE
 #   ROCKET             LAUNCHES    METHOD           USED

 1 - Little Joe II -------- 1 --- Para(12) --------- A3-4T
 2 - Helio-Copter --------- 1 --- Para(12)&Heli ---- B6-2
 3 - Space Shuttle America- 0 --- Para(12)&Gliders - C6-3
 4 - Venus Probe ---------- 1 --- Para(12&18)------- C6-3
 5 - Optima --------------- 1 --- Para(24) -AT-RMS-24mmE11-5J

Location:    Spokane, WA
Time:        4:00PM - 4:30PM
Temperature: 96 F
Wind:        NE 5-10 MPH
Conditions:  Blue skies with high scattered clouds
Attendance:  5 people

My family is on vacation back East, and I'm playing bachlor
for a few weeks until I can catch up with them.  I was invited
over to a co-workers house for dinner, and decided to bring a
few rockets along to entertain their kids for awhile.

1 - Little Joe II
The second flight for this mini-engine scale model of the
Apollo capsule test vehicle.  Perfect shot into the air...and
it landed less than 15 feet from the pad.  A nice start!

2 - Helio Copter
First time I've launched this bird on a "B6" engine...I
usually use "C's".  The altitude was respectful considering
the motor used, but was nothing to brag about.  The nose cone
came down in "Helicopter" mode as advertised, but its tip was
pointed UP towards the sky instead of DOWN at the ground.
That's the first time I've seen that happen with this rocket
(I have 2 of them).  I'm sure some weight in the nose would
alleviate the problem.

3 - Space Shuttle America
The maiden flight for this model, which I bought to replace
the one that did a "Death Dive" during my 4th of July launch.
It's one of the COX RTF (Ready To Fly) models.  Good altitude,
and the ejection charge worked flawlessly this time which
allowed the two parasite gliders to detach without incident.
The gliders are well-trimmed for a RTF model, and the kids
enjoyed chasing them as they circled around the field.  Glide
time was approximately 35 seconds.

4 - Venus Probe
Another favorite of the kids.  The larger chute on the "probe"
kept it in the air for approximately 45 seconds more than the
"booster" module.

5 - Optima
The same motor setup I used at the 4th of July launch...with
the same result.  The gold retaining ring at the bottom of the
AeroTech motor case blew out, along with the propellant slug.
The slug looks to be about 95% intact.  I made sure to reverse
the orientation of the case for this flight, (what was
originally the "Top" of case I made the "Bottom").  If the
case blew, I expected it to blow from the "Ejection Charge"
end this time...not the "Thrust" end.  I've had no problems
with my 29mm case, so I guess my 24mm case/retainer ring has
a problem.  I'm 2-for-2 failure wise with the 24mm case.

No damage was imparted to any of the rockets...a first for me.
Well, that's it.  This posting was short and to the point.
(unlike my last launch posting)!

Regards,
M.Howe
"Eschew Obfuscation"

 
 
 

Launch Report - 07/28

Post by Mike Form » Tue, 30 Jul 1996 04:00:00



Quote:

> 2 - Helio Copter
> First time I've launched this bird on a "B6" engine...I
> usually use "C's".  The altitude was respectful considering
> the motor used, but was nothing to brag about.  The nose cone
> came down in "Helicopter" mode as advertised, but its tip was
> pointed UP towards the sky instead of DOWN at the ground.
> That's the first time I've seen that happen with this rocket
> (I have 2 of them).  I'm sure some weight in the nose would
> alleviate the problem.

We've got a Helicat from the starter kit of the same name, and it appears
to have the same nosecone/rotor blade setup of the Helio Copter. Instead
of spinning down steady, it spins, nose down, and really begins to turn.
Then, it seems like it "stalls" and flips over upside down and does the
same thing... The rotation accelerates to a certain point, and then it
"stops and falls over" and does it again. I'd really like to know the
explanation for this phenomon.

Mike

--
Mike Forman                                                  NetWorks
Internet Services Manager/Midwest                       616 Jefferson  

913-295-5648                                http://www.cjnetworks.com
"Roger, Odyssey, we copy your venting..."Jack Lousma Apollo 13 Capcom

 
 
 

Launch Report - 07/28

Post by Patrick M. Fraze » Wed, 31 Jul 1996 04:00:00


Quote:

> LAUNCH REPORT  07/28/96 - 5 TOTAL
> =================================
(snip)
> 5 - Optima
> The same motor setup I used at the 4th of July launch...with
> the same result.  The gold retaining ring at the bottom of the
> AeroTech motor case blew out, along with the propellant slug.
> The slug looks to be about 95% intact.  I made sure to reverse
> the orientation of the case for this flight, (what was
> originally the "Top" of case I made the "Bottom").  If the
> case blew, I expected it to blow from the "Ejection Charge"
> end this time...not the "Thrust" end.  I've had no problems
> with my 29mm case, so I guess my 24mm case/retainer ring has
> a problem.  I'm 2-for-2 failure wise with the 24mm case.

If an RMS motor blows the aft closure, I'd expect the threads on either
the casing or the closure to be quite mangled.  If it's in good enough
shape to reassemble after the first failure, I wonder if the aft closure
was machined incorrectly.  (Too small, such that the closure could slip
the threads)  Regardless, my guess (without seeing the casing) is that
it's either defective or damaged.  You probably should contact Aerotech
and see if your situation merits a warranty replacement.  (It should)

(slight topic change)
Question for the group:  what is the designed failure mode in an RMS
motor overpressure?  My assumption was that the nozzle should shear at
the shoulder.  Or, is the aft closure designed to strip free?

-Patrick
   -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

   Computer Engineer                     http://www.beacon.com/~frazer
   The Beacon Group                        P 419.289.0558   F 289.8923

 
 
 

Launch Report - 07/28

Post by Hawk_Ds » Wed, 31 Jul 1996 04:00:00


Quote:

>(slight topic change)
>Question for the group:  what is the designed failure mode in an RMS
>motor overpressure?  My assumption was that the nozzle should shear at
>the shoulder.  Or, is the aft closure designed to strip free?

>-Patrick

Mark, Patrick.

RMS cases are made to strip the threads if they overpressurise. This
clearly is a far better fate, then say, the motor blowing up like a pipe
bomb...

The only time I saw this happen was at LDRS. The motor shot off this
full scale something rocket. Small flaming ball. It was out before it hit
the ground. Although, it was a very large rocket... and the case
had to be in the 54mm to 98mm range...

Small ball... Big money.

--
Henry Oeser...NAR# 65336. TRA# 4782. NOVAAR #205

"We Need A Bigger Boat..."

 
 
 

Launch Report - 07/28

Post by Jerry Irvi » Wed, 31 Jul 1996 04:00:00



Quote:

> (slight topic change)
> Question for the group:  what is the designed failure mode in an RMS
> motor overpressure?  My assumption was that the nozzle should shear at
> the shoulder.  Or, is the aft closure designed to strip free?

When the hydro tests were conducted the design failure mode was nozzle
shear.  This is what was claimed to CPSC and NFPA as the reason there was
no shrapnel hazard.  However the actual failure mode we have seen in
practice seems evenly divided between closure rip and nozzle blow.

"Kosdon" reloadables add complete casing frag to the list.

So much for safety, promises and "safer motors".

Just Jerry

This post MUST not be interpreted as criticizim, but a mere accurate
statement of the facts.

--

Box 1242, Claremont, CA 91711 USA
Opinion, the whole thing.

 
 
 

Launch Report - 07/28

Post by Alexander, Randolp » Wed, 31 Jul 1996 04:00:00


Instead

Quote:
> of spinning down steady, it spins, nose down, and really begins to turn.
> Then, it seems like it "stalls" and flips over upside down and does the
> same thing... The rotation accelerates to a certain point, and then it
> "stops and falls over" and does it again. I'd really like to know the
> explanation for this phenomon.

Me too, that sounds pretty cool.  I'm in the middle of building one
myself.  I wonder if you can induce it to do that.  I like when rockets
do interesting things like that in the air.  I take it you didn't add
any nose weight.  I wonder also if it has anything to do with the angle
of the blades.
 
 
 

Launch Report - 07/28

Post by Jerry Irvi » Thu, 01 Aug 1996 04:00:00


Quote:



> >"Kosdon" reloadables add complete casing frag to the list.
> motor cato with "casing frag". Perhaps you are referring to some of his
> large EXPERIMENTAL motors that are not commercially available (O and up)
> that have split the aluminum casing.

Perhaps I am.  Perhaps the posts of case failures are misstated.  However
I have seen published reports of what you call "split" which is a
non-defined failure mode in any case.  The point is that both styles of
reloadable as currently shipped do in fact fail in methods other than as
designed for.  The point being made if even one such failure occurs.  Keep
in mind there are only about 2500 HPR flyers now, and perhaps 25% of them
actually fly reloadables regularly.  What if USR goes back into business
again and revives its 10,000 customers?  I personally designed the snap
ring reloadables in such a way including reload design rules which Kosdon
violates, to absolutely prevent split or frag or rip or whatever you want
to call it because that was the primary concern of NAR, CPSC, NFPA, etc
when these were released in 5-90 by USR, 7-90 by Vulcan and 8-90 by AT.
Only AT went forward with consumer deliveries before any approvals,
classifications, certifications, etc.

Quote:
> Steve "smelly<g>" Cello

<g>

Jerry "litigation sucks" Irvine

"Nobody won.  Each person got what they petitioned for."

--

Box 1242, Claremont, CA 91711 USA
Opinion, the whole thing.

 
 
 

Launch Report - 07/28

Post by PaulDimi » Thu, 01 Aug 1996 04:00:00



Quote:

>No damage was imparted to any of the rockets...a first for me.
>Well, that's it.  This posting was short and to the point.
>(unlike my last launch posting)!

I liked both of them!  Keep 'em coming.  mmm The launch reports that
is...8-)

Paul.

Fly Baby Fly!

 
 
 

Launch Report - 07/28

Post by Smcel » Thu, 01 Aug 1996 04:00:00



Quote:

>"Kosdon" reloadables add complete casing frag to the list.

>So much for safety, promises and "safer motors".

>Just Jerry

I overpressurized a Kosdon motor once by using the wrong nozzle (too
small)... the casing DID NOT "frag". the snap ring groove expanded and
allowed the snap ring and nozzle to exit the rear of the motor... AS
ADVERTISED. Further, I have never seen a commercialy available Kosdon
motor cato with "casing frag". Perhaps you are referring to some of his
large EXPERIMENTAL motors that are not commercially available (O and up)
that have split the aluminum casing. I would not call these "casing frag",
as the aluminum casing splits open and comes down in one large piece....
doesn't throw fragmets as a steel casing might.
Just what I've seen for the last few years,
Steve "smelly<g>" Cello
 
 
 

Launch Report - 07/28

Post by homer10 » Sat, 03 Aug 1996 04:00:00


Quote:


> Instead
> > of spinning down steady, it spins, nose down, and really begins to turn.
> > Then, it seems like it "stalls" and flips over upside down and does the
> > same thing... The rotation accelerates to a certain point, and then it
> > "stops and falls over" and does it again. I'd really like to know the
> > explanation for this phenomon.

> Me too, that sounds pretty cool.  I'm in the middle of building one
> myself.  I wonder if you can induce it to do that.  I like when rockets
> do interesting things like that in the air.  I take it you didn't add
> any nose weight.  I wonder also if it has anything to do with the angle
> of the blades.I've built two and flown one in the last few weeks without witnessing the

same behavior.  Perhaps the blades are in upside-down and when they spin
fast enough it causes the nosecone to invert until it slows rotation
again.
Mark
 
 
 

Launch Report - 07/28

Post by Mike Form » Sun, 04 Aug 1996 04:00:00


Quote:



> > Instead
> > > of spinning down steady, it spins, nose down, and really begins to turn.
> > > Then, it seems like it "stalls" and flips over upside down and does the
> > > same thing... The rotation accelerates to a certain point, and then it
> > > "stops and falls over" and does it again. I'd really like to know the
> > > explanation for this phenomon.

> > Me too, that sounds pretty cool.  I'm in the middle of building one
> > myself.  I wonder if you can induce it to do that.  I like when rockets
> > do interesting things like that in the air.  I take it you didn't add
> > any nose weight.  I wonder also if it has anything to do with the angle
> > of the blades.I've built two and flown one in the last few weeks

without witnessing the

Quote:
> same behavior.  Perhaps the blades are in upside-down and when they spin
> fast enough it causes the nosecone to invert until it slows rotation
> again.
> Mark

You can't really install the blades in upside down. They wouldn't deploy
right. I've also seen it start spinning in the "upside down-nose-cone on
top" mode, and flip. The stalling seems to be related to the speed of the
rotation. After it spins up to a certain speed, it falls off.

Mike

--
Mike Forman                                                  NetWorks
Internet Services Manager/Midwest                       616 Jefferson  

913-295-5648                                http://www.cjnetworks.com
"Roger, Odyssey, we copy your venting..."Jack Lousma Apollo 13 Capcom