New CMASS Member Introduction

My name is Dave and I reside in Rehoboth, MA along with my wife and our 1 year old son. I am employed as a civilian crash/rescue firefighter at an Air Guard base in RI (home of the annual RI Air Show) and also volunteer with my towns fire department. In terms of rocketry I would say the 'rocket bug' first bit me in 1989 when at age 5 I had the honor of watching in person Shuttle Discovery launch for STS-29. Now about 26 years later the 'bug' really taken hold again and I am very motivated to learn all I can about this subject.

I have dived in head first; joined NAR & CMASS, begun reading "Modern High-Power Rocketry 2" cover to cover, and procured a Madcow Torrent kit which I anticipate completion of by the end of the month. I will likely have a few questions for the knowledge pool here on the forum regarding certain construction/configuration matters of this rocket and will be sure to bring them up as they arise.

My goal of course is to obtain my L1 certification at some point this summer. The ideal situation would be to accomplish this at the April launch. Besides wanting to fly my rocket as soon as possible, an odd work schedule means I am off for only a certain number of launches and would like to make an attempt at the first one possible such that if I do not pass (knock on wood) I will have more opportunities this year. With this in mind I have a few questions:

1) What is the procedure for 'officially scheduling' an L1 attempt? Do I make specific arraignments ahead of the launch or simply show up?

2) I intend to fly this rocket with a Cesaroni H125 motor, preliminary simulations show a max alt of 1270ft; is this an appropriate launch for the Amesbury site considering it will be a motor ejection? (I understand weather may play a factor).

Anyways I'll keep my questions to those two for now (more to follow I assure) and I look forward to becoming involved in the club/hobby.

- Dave

Thank you Kenn and Bob for the information, I appreciate it.

Bob - I actually took advantage of the CTI L1 Cert special in an order from Apogee (they allow you to buy one reload for use in your cert flight). So I ended up getting the case for free which was a good deal, the only drawback was paying the hazmat shipping cost which nearly offset what I saved on the case. I guess I could have just bought the items at the field but I feel better having everything I need ahead of time.

I will have to look into and consider your suggestion of the H225. Really the only reason I initially went with the H125 is because that was one of the suggestions from the retailer whom I purchased the kit from, but now that I look at the numbers I can see your point about it being a little slow off the pad. I ran the numbers through rocksim -

H125
Launch guide length: 60.0000 In.
Velocity at launch guide departure: 40.7067 ft/s
The launch guide was cleared at : 0.299 Seconds
User specified minimum velocity for stable flight: 43.9993 ft/s
Minimum velocity for stable flight reached at: 70.0730 In.

H225
Launch guide length: 60.0000 In.
Velocity at launch guide departure: 57.4354 ft/s
The launch guide was cleared at : 0.219 Seconds
User specified minimum velocity for stable flight: 43.9993 ft/s
Minimum velocity for stable flight reached at: 36.3261 In.

These numbers are assuming a usable guide length of 5 feet. I believe I read somewhere that the launch rods you guys have available are 6 and 8 feet but I went with 5 to error on the side of caution. It looks like the H125 would leave the guide at 40ft/s while the H225 would leave the guide at 57ft/s. I think you are right the H225 is probably the way to go, I will have to try to pick one up at the field on the day of the launch. Thanks again for the info!

Well I've pretty much completed construction on my rocket for my L1 attempt. I'm very happy with how it turned out. Heres a few pics:

Here it is completed before paint:



And after paint:



I went with the design scheme of a Mercury Redstone, which seemed appropriate for my first high power flight. Also I am fairly certain this flight will remain suborbital . I am, however, hopeful that this does not jinx me with a reenactment of MR-1 (the so called four inch flight)!

The only hiccup I've run into thus far is that removing masking tape from the coupler (for the paint job) some of the cardboard tube peeled off along with the tape. This removed the shinny smooth surface of the coupler and its now a little rough. When the coupler separates from the main body there seems to be some increased friction now and I'm worried this may affect the chute deployment. I am thinking of just sanding the tube with a very high grit paper to see if that helps, anybody have any other suggestions?

Thanks