Madcow Torrent for Jr. High Power Certification

Oh okay cool, I'v heard the H123 discribed in that way and It kinda stuck. I know though that with the H123 the rocket goes to about 900 feet in RockSim. I just don't feel all that comfortable about the rocket not breaking a thousand feet... It might be an irrational feeling but it just seems a bit too low. Also with glassing the fins and using heavier duty adhesives than what the kit was originally designed for I'd feel a bit safer with a little extra power.

Was just about to start painting the color coat on the rocket when I looked closer at the rocket and noticed a ton of small imperfections on the fins and fillets. So back to the bondo and sanding. Hope to paint one last primer coat tomorrow before starting the color coat.

I seem to recall something about the Telemetrum and metallic paint not working well together. Your signal may be attenuated a bit, if you go that route.


Later!

--Coop

First, nothing wrong with 900 feet. That is plenty high enough to destroy a rocket should recovery fail. And it gives you some room for a late deployment. The other thing is that if your going single deployment, the rocket will be closer to the launch point when it lands. If you have some options on case including adapting to 29 mm, the H128 and H165 motors will give similar performance and one might exceed the 1000 foot mark without going much higher.

I am sure you have, but be sure that you have updated your sim file to reflect the true dry weight of your rocket. And be prepared for a bit of a shock at just how much the finish weighs.


Kirk

My torrent is averaging 1350 ft on a CTI H225, it is weighing in at 5.3 lbs. these flights had the altimeter in the av bay, but setup for single deploy using the motor ejection charge. Also no recovery equipment in the payload section. I believe wfcook got just under 1k ft using the H123 with his torrent and he had all the recovery gear for dd inboard but did a single deploy as well.

Okay right now Rocksim is predicting 900 ft with the H123 with the updated weight... I'm not sure . I'll probably go with the H123 or something of similar size. Just around 1000 ft. Plus or minus a few hundred. To my head though, 900 feet just sounds low. I guess it's really not much lower than 1000 feet. it just mentally seems that way to me.

Looking at my flight log this morning and my torrents first flight was a CTI H152 reaching 1361 ft, and second flight was CTI H225 reaching 1342 ft. I would recommend moving up just a bit, wfcook's torrent was a little wobbly off the rail on the H123 which is why I went with the H152 for the first launch.

Yeah I did notice that with the H242 the velocity off the rail was about 60 fps while the H123 was about 40 fps.

RAHagen said:

Yeah I did notice that with the H242 the velocity off the rail was about 60 fps while the H123 was about 40 fps.

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Remember that the altitude you will get is more closely coupled to total impulse than average thrust (though that obviously is a factor). All of those 2-grain loads are going to hit very similar altitudes, maybe 300 feet of total range. I still think you're better off on a cert flight with a motor that has some kick, and the H225 is still my recommendation. Remember that this rocket can handle a small J quite well, so the H225 isn't going to stress it in any way if you've built it even remotely well, and with the glassed fins and other weight you have added at the aft end of the rocket I'd want more initial thrust than you're going to get out of an H123.

wfcook said:

Remember that the altitude you will get is more closely coupled to total impulse than average thrust (though that obviously is a factor). All of those 2-grain loads are going to hit very similar altitudes, maybe 300 feet of total range. I still think you're better off on a cert flight with a motor that has some kick, and the H225 is still my recommendation. Remember that this rocket can handle a small J quite well, so the H225 isn't going to stress it in any way if you've built it even remotely well, and with the glassed fins and other weight you have added at the aft end of the rocket I'd want more initial thrust than you're going to get out of an H123.

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Yeah that makes sense. I just simulated it in RockSim and the Rocket went to around 1200 ft. That's about in the range I was looking for. So at the moment I looking at either the H242 or the H225. They have about the same velocity off the rail, around the same time to apogee, and about the same altitude. So I guess all I have to decide between them is whether I want to go with an Aerotech or Cessaroni casing. There's so many H motors to decide from compared to G motors!

RAHagen said:

Yeah that makes sense. I just simulated it in RockSim and the Rocket went to around 1200 ft. That's about in the range I was looking for. So at the moment I looking at either the H242 or the H225. They have about the same velocity off the rail, around the same time to apogee, and about the same altitude. So I guess all I have to decide between them is whether I want to go with an Aerotech or Cessaroni casing. There's so many H motors to decide from compared to G motors!

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Either motor should make for a good cert flight. It just depends on which brand of motor you want to use. The CTI motors are a lot easier to use, but cost more in the long run with many flights. I typically use CTI, mostly because AMW shows up to sell motors at almost all of our launches, and I like to support that. The H225 withh probably got about 125 ft higher than the H242, but the off-the-rail behavior should be very similar.

Good luck with the flight! When are you doing it? We all expect a full report, pictures, documentary films, interviews, etc

wfcook said:

Good luck with the flight! When are you doing it? We all expect a full report, pictures, documentary films, interviews, etc

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Thanks! Well... I was hoping to get to make an attempt at the end of August but the RRRocketeers where I usually launch and was planning to make my attempt with just got word today that they have lost their launch site until an unspecified time. So at the moment I'm back to looking for a launch site that will have people to sponsor a cert flight. The next closest club is DARS in Dallas, Texas and they just had their yearly high power launch a month ago so they won't have another till next year. So at the moment the date of when I'll be able to do a cert attempt is at the moment unknown. When I do, however, I'll make sure to dig up the thread and post the results.

RAHagen said:

... The next closest club is DARS in Dallas, Texas and they just had their yearly high power launch a month ago so they won't have another till next year. ...

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I have it on good authority that DARS is planning an HPR launch on Saturday August 23rd. The web site hasn't been updated yet but I encourage you to swing by (www.dars.org) and sign up on our Yahoo group to get the latest announcements.

Yep, and to add to Sam's reply, DARS has been averaging a HP once a month as long as there are no weather or burn ban issues.
There will be plenty of fliers at the Aug launch that can witness your cert flight and sponsor your flight.
I'd be happy to do either.

Check out the Yahoo group listed above for launch status and information.

Gunter is a great place to fly, lots of room for recovery.

By the way, we have a motor vendor on site at Gunter if you chose to fly Aerotech. He always has a large selection of motors, plus the full line of AT DMS single use motors.
You can check out his offerings at buyrocketmotors.com.

TXnrcr and samb, really? Last time I looked at you guys' website there was a high power launch that happened in July but I didn't see another for the rest of the year on your calendar. I assumed that it meant you only had one once a year. If there is one coming up soon i might just skip the five hour drive and come to one a little closer. Thanks!

RAHagen said:

TXnrcr and samb, really? Last time I looked at you guys' website there was a high power launch that happened in July but I didn't see another for the rest of the year on your calendar. I assumed that it meant you only had one once a year. If there is one coming up soon i might just skip the five hour drive and come to one a little closer. Thanks!

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Yes, Saturday Aug 23rd at the Gunter launch site.
The HP launches for Aug and Sept were just scheduled at the Aug club meeting.
The Yahoo DARS Notify link from the contact page of the club website is the best place to see latest launch announcements and updates.

We have approx 3 miles of recovery area. Cattle ranch, no crops. 1 mile waiver. On site motor vendor.
Come on out and fly.

RAHagen said:

TXnrcr and samb, really? Last time I looked at you guys' website there was a high power launch that happened in July but I didn't see another for the rest of the year on your calendar. I assumed that it meant you only had one once a year. If there is one coming up soon i might just skip the five hour drive and come to one a little closer. Thanks!

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Really !!! Would we lie to ya ? :wink: And web site calendar update issues aside, the best way to get the most up to date info (and last minute cancellations) is to click on the mailing list link on the front page.

RAHagen said:

TXnrcr and samb, really? Last time I looked at you guys' website there was a high power launch that happened in July but I didn't see another for the rest of the year on your calendar. I assumed that it meant you only had one once a year. If there is one coming up soon i might just skip the five hour drive and come to one a little closer. Thanks!

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Join us, come on, all the cool kids are doing it. As was mentioned, we even have an on site pusher, I mean motor dealer.

Cl(VII) said:

Join us, come on, all the cool kids are doing it. As was mentioned, we even have an on site pusher, I mean motor dealer.

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Haha! Yeah I'm not sure if I could do the August launch since it's a bit short notice and I'm still finishing the rocket but I could definitely do September. There were two dates for the hp launch in september listed on the Yahoo group do you guys know which one it is?

RAHagen said:

Haha! Yeah I'm not sure if I could do the August launch since it's a bit short notice and I'm still finishing the rocket but I could definitely do September. There were two dates for the hp launch in september listed on the Yahoo group do you guys know which one it is?

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You can make it. When I got my level 1 cert with my torrent, the RSO took the rocket, sniffed it, and asked me if I had painted it that morning...


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You can do it! The motor exhaust will mask the paint fumes!

RAHagen said:

Haha! Yeah I'm not sure if I could do the August launch since it's a bit short notice and I'm still finishing the rocket but I could definitely do September. There were two dates for the hp launch in september listed on the Yahoo group do you guys know which one it is?

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The last email I have says September 27th. That would have to be right because the third Saturday is always the low/mid power launch in Frisco. As always this time of year, burn bans could be in effect then...I think we're all a bit surprised we may get the August launch off.

wfcook said:

the RSO took the rocket, sniffed it,

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Sure he wasn't just sniffing the glue? :wink:

race 58 said:

Sure he wasn't just sniffing the glue? :wink:

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Possible. But as it happens, I had in fact painted it at about 3am that morning...You could smell the paint from some distance away. If you touched it fingerprints were left behind.

I built the Torrent, the Drei Max, and a stock MDRM all in a little less than three weeks. Long story...it was a bit hectic there at the end.

Anyway...it can be done!

Yeah I might be able to go to the August launch. The thing is my dad wants to be there to watch but he has a very erratic work schedule (he's an airline pilot). He is on call and can't be any further than an hour and a half from DFW airport. We won't know if he is off till the night before. If I plan for the September launch however he can bid for that day off and there's a better chance he can get off. So at the moment it looks like it'll probably be the September launch... But it might be the August launch...

samb said:

I have it on good authority that DARS is planning an HPR launch on Saturday August 23rd. The web site hasn't been updated yet but I encourage you to swing by (www.dars.org) and sign up on our Yahoo group to get the latest announcements.

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WIth enough interest and support HPR might become a monthly activity in DARS. I can't wait for August 23rd. And with the local vendor makes things better. See you there in Gunter,tx in August 23.

Yes, DRS definitely has more than one high power launch a year. Didn't know there was a launch on the 23rd because I was out of town for the meeting. But Sam would never lie to you. Encourage my daughter launch more rockets - yes, but never lie.


Kirk

If you do launch with DARS, I would certainly go with adding a few hundred feet in favor of more launch speed. While there are moments of calm, there are many more with a good breeze going on the field.


Kirk

1tree said:

If you do launch with DARS, I would certainly go with adding a few hundred feet in favor of more launch speed. While there are moments of calm, there are many more with a good breeze going on the field.


Kirk

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Thanks I probably will. Texas weather can be quite erratic. At the moment I plan to fly with you guys unless in some amazing occurrence the club I usually frequent finds a new launch location capable of supporting high power. I won't know whether I'll be able to make it to the August launch for a while. It might be tomorrow night it might be the night before the launch. I'll make sure to post it when I get the info.