Hydra flight result

[Karl]

Well it was the Saturday of UKRA today , and I finaly got chance to fly my 2nd Hydra 7 on all 7 motors . It flew on 3 C6-0's , 1 C6-7 and 3 C6-5's. Each motor was individually wired up with quick match and a Ignitor was inserted. The rocket was put on the pad and waited for the next flying session to commence.
As the next flying session started the nerves started to kick in , the ignitors were wired up and the countdown on the tanoy began. At launch the quickmatch burst into flames and the rocket jamp into the air to about 10ft where it went CRAZY. It span under full power of 6 C motors , which resulted in it spacking , TOTALING the rocket completely , chargrilling the insides & outsides , and leaving me feeling like a prat ( my first flight of the day after recieving so many comments on it's great looks ). At first me and a RSO thought a motor CATO'd but after inspection we found none of the motors CATO'd at all but the aft end of the body tube majorly crumpled due to force of all 6 motors. After returing home I found out that the motor tubes & main body tube & small nosecones are un-repairable , which leaves me distraught as I have only had this kit a few days now , and was one of my best looking rockets. Even though 1 motor didn't light , it still made it off the rod with 6 motors roaring! I'll post some pics of before and after ASAP.
-Karl

 

[firemanup]

Sorry to hear about that Karl..

Trust me i know the sickening feeling... it sucks...

 

[solrules]

sorry about the flight....

I would imagine that the 6 c6 motors peaked at about .25 seconds, with about 3.3 pounds of thrust each. That's about 20 pounds (9 kg) of force on the rocket, I guess that was enough to crush up the tube.

 

[Karl]

I remember a RSO saying it could do with some noseweight but it should be stable without , even though there's no mention of any noseweight being needed in the instructions.
-Karl

 

[Karl]

Here we have the Hydra in all it's glory.
-Karl

 

[Karl]

A view from the nosecone
-Karl

 

[Karl]

Aft end.
-Karl

 

[Karl]

Ohh heres the aft end.
-karl

 

[Karl]

A view of the fins.
-Karl

 

[Karl]

Close up of the vent holes.
-Karl

 

[Karl]

And heres the Evil pictures!
-Karl

 

[Karl]

Fins.
-Karl

 

[Karl]

Burnt motor tubes
-Karl

 

[Karl]

Motor tubes (Mind the hand after trying to recover a rocket from a bush/ditch)
-Karl

 

[Karl]

Note the bubbling of the paint.
-Karl

 

[Karl]

Lower section of the tube.
-Karl

 

[Johnnie]

Karl,

Dueling Hydra's...I launched my today as well, on (7) C6-7's and it too pin-wheeled wildly before impacting backwards into the turf. You faired far worse than myself, as I merely stripped one of the main outer fins. Sorry to see the carnage...is she rebuildable?

Here is the only pic I got of flight with my dinky little key-ring digi-cam

 

[Karl]

I doubt it! The small nosecones are toast , and if I cut a inch off the motor tubes , the insides are still toast. Maybe if I could get some new small nosecones & shock cord/kevlar from Semroc it would fine . The only salvageable parts are ; the Argumentor tube , the payload&coupler&nosecone , and the small fins on the Argumentor tube.
So realy I need most of the aft end of the rocket

Hmm yours did the same on 7 C6's? Maybe we need to add a little nose weight after all?
-Karl

 

[nomopbo]

Karl,
Sorry about your flight. It was a beauty. The "after" photos made me cringe.

Seeing as there were back to back disasters on 7 motors, looks like I wont be attempting that feat on my Hydra.

 

[Karl]

I wouldn't suggest trying it lol . I've had a great flight with 3 C's with my other Hydra kit but I would think thats the max.
-Karl

 

[eugenefl]

Karl, may I suggest you contact their customer service department? I would explain your experience with the kit. Seeing how 7 C's is a recommended motor configuration, I would be a bit disappointed in the awry performance. Additionally, it would give the manufacturer to look into the kit design and determine if a problem exists.

Just a suggestions. Sorry to hear about the errant flight. It's too bad the rocket isn't repairable.

 

[cydermaster]

karl - just a thought....

you buit the kit really quickly - did you use epoxy?
Too much epoxy used to glue on all that finnage may have moved the CG back too far.

As I say, just a thought. Sorry to hear about the Spack!

 

[Karl]

Nope I only used Thick CA to fillet & glue
It was an impressive spack tho' , about 10ft away from the crowd and a deep thump as it hit the ground.
-Karl

 

[cydermaster]

Originally posted by Karl
It was an impressive spack tho'

LOL - Thats what matters - If you're gonna do it, do it with style!

 

[Karl]

LOL! The RSO had a hard time reading out all the motors in this baby! It's now well and truely toast , but one thing I dont get is , why would the tube set fire to itself just because of an ejection charge?! :s
-Karl

 

[Johnnie]

The problem now is, to fly these with the added nose weight, this must be incorporated before the cone is assembled...I clued mine permanently

I too built with CA, but I also used a little 5-minute epoxy on the 7 motor tubes as they were going to have to take a beating with 7 motors kickin it around...at least that worked, they did hold together.

Next one I will build without a payload section. I will glue both main tubes together with the supplied coupler, but not before I drill holes straight thru to make a baffle for the gases to pass through. I will use the nosecone to pop and pull the chute out as normal.

On take off, the chutes and chords all shifted to the rear as well. The above build method will keep this from happening again and will possibly help keep the CG forward.

 

[Johnnie]

Karl said:

why would the tube set fire to itself just because of an ejection charge?!


I loose fit all of my motors except the core motor, to eject themselves when the charges went off, there-by making the Hydra VII lighter for landing. Did your motors stay in letting the charges set fire to the motor blocks maybe??

 

[Karl]

Yep I'll email there sevice department explaining the situation , thanks for that

Johnnierkt , as you have a kit yourself , look in the instructions it says ' Note some builders prefer to leave more engine mounts open to increase the odds that in case all do not ignite , there is a back up ' . This is what I did , I placed the engine block in , but not the cap . The parts what where caught smoldering at recovery where : The tips of the motormounts ( top end ) , rear of the small nosecones , and the very aft end of the bodytube (not the payload).

A way of adding noseweight may be to add a screw with washers on , screwed into the bottom of the nosecone?
-Karl

 

[Karl]

Yep all my motors stayed in , 1 rap of masking tape did it. I wasn't too sure that the RSO would let it fly with motors being ejected.
-Karl

 

[Karl]

Well that day wasnt to good for me , I flew my Sunward Ice-Storm on a C6-5 , it left the pad doing a couple of barrel rolls , then it sharply turned horizontal (still under full thrust) , went over the crowd in a sort of jet fashion , then burnout..........The model was only about 50-70ft high and decending rapidly , JUST before it hit the ground , the ejection fired , shooting the nosecone into the ground a couple of inches , snapping the shockcord , and shooting the rocket backwards a few feet , nice flight though!
-Karl