Semroc Hydra VII

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Boosterdude

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Anybody out there built one of these lately? I've attached a few pics of my build. It's a really neat kit to build, lot's of parts. Can't wait to finish and fly it, seven C6's......get out of here!




 

dcastle

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Yep, mine is on the bench waiting for paint. I have been procrastinating because I can tell right now that masking and painting is going to be a bear -- I'll probably match the colors on the kit cover. Unfortunately everything is glued together...I think that painting before assembly might be a better idea with this kit.

I can't wait to fly it, though, this one should be a lot of fun. I'll probably start on a cluster of 3 Cs rather than the full 7. I also modified it so that 3 of the motor tubes were open to eject the 'chutes. I just couldn't get comfortable with plugging 6 out of 7 tubes as in the instructions. I know from past experiences that when I build something like that, if one motor in the cluster fails to ignite it will always be the one and only one rigged to eject the recovery system. Always.
 

Crazyrocket

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I finished mine over the winter. I modified mine slightly to allow 3 motors access for ejection charge. First flight was on 3 B6-4 and everything worked great. I plan on flying it on 7 B6-4 this weekend.
 

dpower

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Anybody out there built one of these lately?
Well, lately, no; but 3 years ago...

Did you build it with just one open motor tube or more? If you kept more than on open, I would recommend putting a small dab of epoxy at each point where the nose cone halves meet the motor tubes & upper tube. This provides some protection for the ejection charge coming up the outside motor tubes. If you only kept one open motor tube, make doubly sure that center motor lights! (I kept 3 tubes open) I have flown mine on a variety of 7 motor clusters, including:

3xB6-4 + 4xB6-0
3xA8-5 + 4xC6-0
3xC6-5 + 4xA10-PT

But never a full load of 7 C's. I would not recommend a single C motor, but it flies fine on 3. Oh, and it is a *lot* easier to paint if done before the aft ring is glued on. I like to plug the booster motors, so they don't kick out.
 

RocketsNorth

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I finished mine over the winter. I modified mine slightly to allow 3 motors access for ejection charge. First flight was on 3 B6-4 and everything worked great. I plan on flying it on 7 B6-4 this weekend.
Can you share some pics or video of the launch?

I've had the plans for this for awhile but am nervous to start on it:blush:
 

Crazyrocket

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I'll try to get some pictures of the launch. My wife usually takes to photos. I always like to see the entire flight!
 

sandman

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Has anybody flow a Hydra on the new Quest long burn motors?

That would be COOL!
 

Boosterdude

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Finally got a chance to finish the Hydra. The humid weather makes painting impossible during most of the summer in NC. This kit was excellent, all of the balsa provided was perfect and laser cut. I'll post some pictures tonight of the finished product. Can't wait to see it go, it sure looks cool.
 

Boosterdude

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Here are the pictures. As you can see I went for more of a military look. The Hydra is a lot of work to get the grain fill and ready for the final color coats. But you are rewarded by a really cool looking rocket.



 

KerryQuinn

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I built the Hydra-7 this spring. I chose to leave the center engine plus one of the outer engines open for ejection. I painted most of the parts before building which was a good choice. First launch was on 7x Quest C-6-5 (photo of liftoff below). beatiful lift off. near apogee you could hear 7 distinct "pops" - but there was no separation / no chute. Kit lawndarted in so fast you could hear the whistle as it dove deep into - the swamp (see picture). Intrepid RSO Mark Bundick volunteered to wade into the swamp (without realizing that it was going to be 2+ feet deep) to retreive my rocket.
Upon inspection, it was clear that all 7 engines fired and that both of the engines used for ejection were still in the rocket - the back end of the rocket was all that could be recovered - so no real explanation. The "fit" of the nose section prior to launch felt perfect....

So, I did what anyone would... I rebuilt it... and renamed it the "Swamp Bunny 7". The new rocket was nearly identical, but I added 6" of length to move the CG further a bit more than the original. I also made extra sure that the holes near the half-nose-cone-section were fully plugged as I thought this might have been the problem.

Second launch, same launch site 2 months later.... 7x Quest C-6-5 engines.
EXACTLY SAME RESULT - except that this time I missed the swamp and lawn darted onto mother earth. As you might expect, singificantly more damage hitting earth versus the "forgiving" swamp.

Maybe someday I'll re-build it once again, but for now I'm working on other things to keep my mind off the Hydra....

By the way, the Q2G2 ignighters are THE BEST - I've 7/7 on the Hydra twice. (4/4 5 times, 3/3 2 times and 2/2 10 times on other rockets this summer) See the picture for the Q2G2's after the Hydra launch....

-Kerry

5971_1102674045638_1190334185_30296525_7934468_n.jpg


quest_cluster.jpg
 

jadebox

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I launched mine on three C motors a few times.


I built it with three of the engine tubes open on top for ejection. The other four are sealed.

BTW, I never had this problem, but someone on one of the forums recommended taping recovery wadding (or "dog barf") over the ends of each of the motors. This is just in case one fails to light. The insulation prevents the ejection charge of one of the other motors from igniting the unlit motor which would then burn from the wrong end.

A couple of fins are broken on my Hydra VII right now. They broke during transportation. I bet it would fly fine without them, but I'll fix it before its next flight.

-- Roger
 

jadebox

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...near apogee you could hear 7 distinct "pops" - but there was no separation / no chute.
I guess once one of the motors failed to deploy the 'chute, it left an opening so that none of the others did. But, even with an opening through the spent motor's nozzle, it's surprising the next motor's ejection charge failed to pop the 'chute.

-- Roger
 
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DanFrank

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Upon inspection, it was clear that all 7 engines fired and that both of the engines used for ejection were still in the rocket - the back end of the rocket was all that could be recovered - so no real explanation. The "fit" of the nose section prior to launch felt perfect....


Second launch, same launch site 2 months later.... 7x Quest C-6-5 engines.
EXACTLY SAME RESULT - except that this time I missed the swamp and lawn darted onto mother earth. As you might expect, singificantly more damage hitting earth versus the "forgiving" swamp.

-Kerry
It sounds like there were air leaks where the 7 tubes transition to the 1 big body tube. I had to put epoxy "fillets" around each of the halved nose cones and small body tube edges in order to get a good seal.
This rocket goes quite high with 7 C6 motors.
Daniel
 

Crazyrocket

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I agree with Daniel. I filled the gaps and ensured that everything was sealed. I've launched mine on 3 B6 and 7 B6 motors. I too left three motor tubes open to the BT.
 

dpower

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Here are the pictures. As you can see I went for more of a military look. The Hydra is a lot of work to get the grain fill and ready for the final color coats. But you are rewarded by a really cool looking rocket.
Nice looking Hydra John, this is one of my favorites!
 

Boosterdude

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Thanks Paul, I can't wait to fly it. The Hydra is a really cool design by Semroc, nice kit as well.
 

Boosterdude

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Well time really does fly, just got the first flight on the Hydra yesterday. I used 7 x C6-7's, and all of the ignited simultaneously using Quest igniters. Perfectly stable/straight boost to over 1500' easily. No damaged so it's ready to go again. This rocket is a lot of fun, and the 7 C's is really something to watch.

 

Astro-Baby

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Amazing looking bird and what a fantastic job too.....:)
 

NJRick

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what an awesome picture!! Beautiful job!!!

Well time really does fly, just got the first flight on the Hydra yesterday. I used 7 x C6-7's, and all of the ignited simultaneously using Quest igniters. Perfectly stable/straight boost to over 1500' easily. No damaged so it's ready to go again. This rocket is a lot of fun, and the 7 C's is really something to watch.

 

foamy

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Very cool. That rocket never interested me until now. Nice work and a good photo.
 

himitsu

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A beautifully done finish! I also was not too interested in this model, until now. Seeing photos of the real deal does make a difference.

Plus, that rocket is huge. It makes you look smaller (and younger) than I would have expected.

Here are the pictures. As you can see I went for more of a military look. The Hydra is a lot of work to get the grain fill and ready for the final color coats. But you are rewarded by a really cool looking rocket.



 

dpower

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7 x C6 on the first flight, nice! Did you need any nose weight, beyond the provided washer?
 

gdjsky01

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Wow. Thread started in 2009????
Well time does fly. :y:
 
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