Discovery Science Fastest to 10,000' Race (LDRS30)

Discussions on high/extreme altitude and mach busting rockets.

Moderator: Moderators

User avatar
kopius
Elle3
Elle3
Posts: 2869
Joined: Mon Apr 23, 2007 4:30 pm
Location: Gold Coast, Queensland
Contact:

Discovery Science Fastest to 10,000' Race (LDRS30)

Postby kopius » Wed Sep 21, 2011 10:09 am

As you are probably aware, A few of us recently had the great opportunity to attend LDRS30 in Argonia, Kansas, hosted by our good friends from K.L.O.U.D Busters.

Discovery Science channel were there filming a number of flights and events including their own Fastest to 10,000 Feet race. With some last minute planning, I teamed up with Cryoscum to enter this challenge.

Nic did an amazing job on rolling the tube and turning the NC and coming in at just over 300grams including everything except motor, SideShow4 was born and definitely a force to be reckoned with!
sideshow4.jpg
SideShow 4
sideshow4.jpg (83.96 KiB) Viewed 3673 times


Packaged up and ready to travel, SideShow4 was an interesting topic of discussion through various airport security points. Most were more interested about rocketry in general throughout the discussion so it was a great opportunity to plug what we do.
sideshow4 packaged.jpg
SideShow 4 packaged for flight
sideshow4 packaged.jpg (68.06 KiB) Viewed 3673 times


Many people were blown away with the build and I was very proud to announce that it was 100% Australian made. Discovery Science paid for a Featherweight Raven to fly, so that coupled with an EasyAs RDF from Wooshtronics was payload of choice for the flight. Prior to flying, contestants had a number of interviews with the TV crew and I quickly earnt the title of "Media Hog" (OK hog was actually another word, but this is family friendly site ;-)). They were quite fond of the Australian crew, could have been because of the Wagon Wheels and Australian Rocketry Stubby Holders I gave them, but I think it was just coz we had traveled so far and were participating with so much gear. It was really kewl to meet Kari from Myth Busters and CJ and I had fun chatting to her (For all the fans out there, yeah she is real cute in person).
kari_cj_kopius.jpg
Crazy Jim and Blake chatting with Kari Byron from Myth Busters before the fast to 10,000' Drag Race
kari_cj_kopius.jpg (57.36 KiB) Viewed 3673 times


Enough of the media and lead up, it was time to fly this sucker! Now original plan was to use a J570W (38/1080), however being the Wildman Distributor that was going to be an issue. (For those who are not aware of the Wildman Oath, you need to buy a kit and learn it!! (Yes this is a sales pitch) Once you have read it, you will understand why a J570 is an issue for this flight. If you want to know the story of how it started email, me, quite a funny story and good work Crazy Jim! haha) Where were we... oh yeah, Tim "Wildman" Lehr found in his stash a J510W which for those who don't know fits a 38/1320 case, has 189 more total Ns than the J570 and burns for .4 of a second longer, needless to say, this was a wild motor that left no airframe space for the faint hearted! With this being said, I used two 3"x3" nomex blankets as a legal form of (vertically challenged) streamers.
sideshow4-loading.jpg
SideShow 4 loaded into tower
sideshow4-loading.jpg (59.94 KiB) Viewed 3673 times


There were many different styles of rockets, of all shapes and sizes. SideShow 4 was the smallest and lightest by far. Before I forget, a huge thanks to Coop for lending me his 38mm tower launcher. Best viewed in HD, I am on the far right...


As you can see, SideShow 4 was CLEARLY the fastest rocket, however unfortunately just under 2 seconds into the burn, we suffered from fin flutter which (by my sad face) can be seen below.
sideshow4-blake-sad.jpg
SideShow 4 Blake sad face
sideshow4-blake-sad.jpg (51.39 KiB) Viewed 3673 times

sideshow4-broken-fins.jpg
SideShow 4 broken fins
sideshow4-broken-fins.jpg (27.07 KiB) Viewed 3673 times


Unfortunately the ejection charge, which was only .4grams was a little too much and sheared the steel wire. After some SARTIME, the nose was recovered, however an already weak signal quickly disappeared and no electronics (or sled) were found.
sideshow4-broken-nc.jpg
SideShow 4 broken nose cone
sideshow4-broken-nc.jpg (20.29 KiB) Viewed 3673 times


A few interesting points:
1. None of the fins tore completely off.
2. The fillets are still in perfect condition and all damage is above them.
3. The kevlar shockcord although partially torn, is still in one piece meaning that it has more than likely sheared through the steel cable.

we have learnt a lot from this project and SideShow 5 is now underway. With the design changes we think it will survive the biggest challenge yet. Unfortunately I can't elaborate too much just yet, but well over Mach 3 in the 38mm configuration is the goal.
QRS Secretary

AMRS #3 L3 ACO
Life member of QRS

NAR L2 #98260

MDRA Member #0241

rocket_troy
Engineer
Engineer
Posts: 1005
Joined: Thu Oct 09, 2008 9:30 pm
Location: Melbourne Australia
Contact:

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby rocket_troy » Wed Sep 21, 2011 10:26 am

Awesome stuff!

I reckon you're soon bound to be the world foremost expert on what energy and force can do to rocket airframes and whatnot from aggressive flight profiles Blake [chuckle]

TP

It ain't rocket surgery...

well... :?
ERG #02

User avatar
ROCKet STAR
Astronaut
Astronaut
Posts: 1724
Joined: Mon Mar 16, 2009 1:40 pm
Location: Blue Mountains, NSW
Contact:

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby ROCKet STAR » Wed Sep 21, 2011 10:42 am

Very impressive despite the problems. :shock: It's a shame the flight computer wasn't found, I can only imagine how fast it must have been going for the carbon fiber to disintegrate like that. Was there any blistering on the nose cone similar to to what Simon and David experienced with their rocket?

Can't wait to see the next one! :D
Chris Barnes

AMRS# 29 - L3

UKRA - L3

User avatar
kopius
Elle3
Elle3
Posts: 2869
Joined: Mon Apr 23, 2007 4:30 pm
Location: Gold Coast, Queensland
Contact:

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby kopius » Wed Sep 21, 2011 10:54 am

Thanks for the reminder, yes there was a lot of blistering on the NC, so I can only assume that it was well into Mach 2 when it fluttered.

haha, you're spot on there TP. It's not aggressive though, just assertive ;-)
QRS Secretary

AMRS #3 L3 ACO
Life member of QRS

NAR L2 #98260

MDRA Member #0241

User avatar
cryoscum
STOP... Hammer Time The Prodigy
STOP... Hammer Time    The Prodigy
Posts: 1802
Joined: Wed Oct 06, 2010 2:54 pm
Location: QLD, NSW & VIC

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby cryoscum » Wed Sep 21, 2011 11:11 am

Strange! The 2pack paint I use didn't blister at all on the Williams mach 2.2 flight, so this must have been quite a bit faster. Also, this was a Von Karman NC and not just some guessed shape like the Williams one, so it should generally deal with the speed better.
AMRS L3 | NAR L3 | QRS 089 | MDRA 224
AMRS Technical Advisory Group

Total impulse for 2016: 32,458 Ns (thus far)
Total impulse for 2015: 84,231 Ns
Total impulse for 2014: 40,757 Ns
Total impulse for 2013: 62,927 Ns

User avatar
Scoop1261
L3 Rocket GURU
L3 Rocket GURU
Posts: 1947
Joined: Sun May 06, 2007 9:29 pm
Location: Perth, Western Australia
Contact:

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby Scoop1261 » Wed Sep 21, 2011 12:00 pm

Media Whog.jpg
Here is Media W....; I mean Hog explaining to the Discovery Channel folks just where it all went pear shaped!

Not sure if he actually knew what he was saying, or if he was just trying to impress Kari!
Kari Byron.jpg
Why Limit Yourself?

AMRS #4 - L3 |TRA #11080 - L3 |MDRA #263

Impulse: A Whole Lot ..So much I've lost count!

hybridhighflyer
Engineer
Engineer
Posts: 559
Joined: Mon Dec 29, 2008 8:02 pm
Location: Sunshine Coast Queensland

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby hybridhighflyer » Wed Sep 21, 2011 12:03 pm

Great work.

I must say I dont think you did anything wrong. Though that does happen when you live life on the edge.

Sumo310
L3 Perfectionist
L3 Perfectionist
Posts: 2057
Joined: Wed Jun 20, 2007 7:48 pm
Location: BRISBANE, Aus

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby Sumo310 » Wed Sep 21, 2011 1:51 pm

We had blistering on the nose and fins, and the tip of the nose was ablated
L3

Kryten
Astronaut
Astronaut
Posts: 1977
Joined: Wed Oct 24, 2007 11:06 am
Location: Sydney

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby Kryten » Thu Sep 22, 2011 7:48 am

Probably an over-simplification:
The fins weren't stiff enough, or too stiff to absorb the vibrations.
Were these just CF/epoxy? How thick?
Increasing the thickness would make them stiffer - you could use a balsa core which wold add very little weight.
However, thicker fins will increase the drag (bit of a Catch-22 situation)

For the result your're trying to achieve, I wouldn't paint it. Just sand & polish
"Pub, ah yes. A meeting place where people attempt to achieve advanced states of mental incompetence by the repeated consumption of fermented vegetable drinks" (“Timeslides”)

Andrew Burns
Rocket Crew
Rocket Crew
Posts: 283
Joined: Fri Apr 25, 2008 1:14 pm
Contact:

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby Andrew Burns » Thu Sep 22, 2011 8:21 am

Yeah fin flutter is just a feedback system between aerodynamic oscilations of the fins and the structural stiffness of the fin. If the aerodynamic frequency of the fins matches to the structural resonance frequency of the fins or one of its harmonics you get destructive levels of oscilation. As flight velocity increases the frequency of aerodynamic oscillation on the fins increases so the faster you go the stiffer your fins need to be to keep their resonant frequency above the oscillation frequency. As Kryten suggests, an easy way to add stiffness without much weight is to make the fins thicker by adding in a balsa or foam core, you do however increase your drag a bit.

PK
...
...
Posts: 1710
Joined: Sun Jun 01, 2008 5:07 pm
Location: Perth
Contact:

Re: Discovery Science Fastest to 10,000' Race (LDRS30)

Postby PK » Thu Sep 22, 2011 9:13 am

Not saying it applies to this case, but there's another modality when the leading edge sweep angle is less than the propovation angle of the shock wave created where the leading edge-body tube discontinuity. The shock wave is incompressible and, if it hits the fin the you get very high point loadings.

I have a spreadsheet somewhere that does the calcs for this and also estimates the chance of fin flutter for a given material, thickness, planform combination.

PK


Return to “Higher, Faster, Further”

Who is online

Users browsing this forum: No registered users and 1 guest