- This topic has 79 replies, 13 voices, and was last updated 14 years, 8 months ago by
John A. Wilke.
John A. Wilke.-
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Bruce R. Schaefer
I remember reading about von Karman in a book called “The Rocket” a while back; all I could remember was that he was “JPL’s” first director. However, he also was fascinated by supersonic airflow, and his nose cone was born from that fascination. He came to this country in 1930, because Germany was getting all nutzy, or maybe that was Nazi. He was from Hungary, not Germany. I sit corrected yet again! Interesting guy though. Warren, you’re absolutely right about, JW. I remember when he had to leave us for a while and he handed Dale one of his few tools, that nifty tool that is sort of a Chinese Swiss Army knife thingy–technically speaking, all tools you need in one handy device. That’s the only time I ever saw Dale tear up. I really think that JW has elves build his rockets. 😉
John A. Wilke
Hey Warren – I now own two screwdrivers 😀
There are some really intense and incredibly capable altitude guys in the club. When going that route, the KISS thing is pretty much gone. Bret, for me – I don’t worry about a poorly-assembled motor or forgetting to arm something or not enough black powder. I worry about stuff like a surface mounted fin fluttering or a nosecone ablating to where a hole forms (I have come close many, many times). I worry about wires pulling out or batteries getting loose… and while folding something is rare, it can be a source of concern when you are pulling 70 gees.
Look over Adrian’s shoulder sometime when he is assembling. It is like doing a jigsaw puzzle with tweezers inside a tube. And it is ALL done to save space, as Warren indicated. It is an amazing testament to patience and engineering and ability. Sean’s (and Doug K’s) stacking three minimum diameter rockets on top of each other has outrageous prepping challenges as well. I’ve also seen Ed D. put some pretty elaborate shots that got considerable altitude. Lots of talent in this club!
The thing I like most about the group is that I think anyone will help you with anything. I’d never have gotten “Rough Draft” off the ground without Warren’s v-bagging. Half (3/4?) of most of my rockets DNA comes from someone else who let me look over their shoulder.
Now doing that elaborate stuff on an L3? In some ways, I think it is crazy. In some ways, I think it the way to go. It is a really interesting discussion.
I remember the very first time I saw a glass rocket. It was a totally incredible concept to me. Now, if you look at the poll on page one of this site, the total reverse is true. I wonder what we’ll be doing in ten years?
Bruce R. Schaefer
John, you need a hammer… for getting those MD motor casings in! I’ll give you mine, or if anyone else needs one. As I told Bret on the way home, NO ONE does this alone. We choose our friends, as opposed to family. Though I love my family. We learn from each other. And, that’s what family does. I’ve made many mistakes, but those mistakes fell away after I watched others make other mistakes. We learn from each other (What? We’re not all geniuses? Genius is observing.). I also told Bret that when James, one of the many E.F. Huttons in the club, speaks, you turn your ear to them and listen. I also told Bret that if I wanted a low TRA number, I should have joined TRA when I got their first newsletter in the early to mid-80’s. Woulda, shoulda, coulda… doesn’t mean anything. I can’t stress enough, and while there were clubs that flew in Lucerne Valley way back then, I never joined. I was building rockets, 3-F’s to 3-F’s, probably shouldn’t have said that. As Chris and Warren stated, it IS the journey. And, when I was searching for my first made parachute, and heard the rockets going off below me, I knew I was home. Bret, if you can’t do your L3 with this club, and we all know you can, you cannot do it anywhere else.
Steve Jensen
Crap. Something new to worry about 😉
Per Wilke: “or a nosecone ablating to where a hole forms”
Uh, this is something I have not worried about. I’ve had polystyrene over Mach 1 with no obvious damage. I am going to try to push a rather thin walled Mad Cow 2.56 inch conical fiberglass nosecone on a big Pro 54 up to 1.5 to 1.8 Mach. Maybe I should sneak up on it…
I seem to continually find new means to mess up my rockets. Ablation of the Nosecone is something new. I sort of think/hope I’m not near that in my rather modest rockets.
Bruce R. Schaefer
I seem to continually find new means to mess up my rockets. Ablation of the Nosecone is something new. I sort of think/hope I’m not near that in my rather modest rockets.
LS, as Bret stated, just because others have done something (either right or wrong–and this is relative), doesn’t mean you will. There are so many variables, most of them are common sense, but the inventiveness lies within oneself to surmount those that aren’t. You can always glass the nose cone with a sleeve or layers of FB. Don’t look for trouble… it will eventually find you. 😉 And at THAT point learning will step in; THAT’S the journey. Sometimes just for you, but most often for others as well. Stop worrying… just think and watch and learn! …Oh, great, this was meant to help…
Chris LaPanse
Crap. Something new to worry about 😉
Per Wilke: “or a nosecone ablating to where a hole forms”
Uh, this is something I have not worried about. I’ve had polystyrene over Mach 1 with no obvious damage. I am going to try to push a rather thin walled Mad Cow 2.56 inch conical fiberglass nosecone on a big Pro 54 up to 1.5 to 1.8 Mach. Maybe I should sneak up on it…
I seem to continually find new means to mess up my rockets. Ablation of the Nosecone is something new. I sort of think/hope I’m not near that in my rather modest rockets.
Honestly, I wouldn’t worry too much at 1.5 to 1.8, as long as you don’t stay there very long. I’ve been there several times with no obvious damage. The region I’m a little concerned about is 2+. I’ve got a motor for Mayhem that should push around mach 2.4, and I’m a bit concerned about that flight.
Bret Packard
And these are the areas were I think the “how hard should you push it on a cert flight” comes into play. While pushing the envlope is certainly part of the fun in our hobby, how far can you push it responsibly? When does th balance between safety and performance get out of whack?
For me, a 5 inch rocket on a 98mm motor capable of just over 20K is pretty exciting. Sure, it may not be minimum diameter, but I am achieving speeds and altitudes that I haven’t ever hit before. That seems like a compelling yet responsible jump into L3 class motors to me. For someone who has built and flown lots of K and L minimum diameter birds, maybe going to an M isn’t that big a jump. I just think we all need to keep in mind that the damage potential goes way up as the rocket size and power goes up.
The fact that it is a cert flight really has no bearing on the build for me. In my estimation, the next logical step in my design and constrution learning curve dictates a bigger airframe and motor.
And I suppose after all that rambling, that really is my only point. I don’t see that it makes alot of sense to oversimplify OR overcomplicate a design and flight JUST because it’s a certification flight. I think each person probably has an idea of the incremental step that they are comfortable with while progressing with their rocketry skills and they should stick with that, regardless of whether or not it’s a cert flight.
Steve Jensen
Tell us so we can all watch! Some times we are all so busy doing our own things at launches that we miss some of the good stuff.
I’m not too concerned about failures, as long as I learn from them. Losing a rocket is the worst, as there’s no learning, closure, etc.
John A. Wilke
And these are the areas were I think the “how hard should you push it on a cert flight” comes into play. While pushing the envlope is certainly part of the fun in our hobby, how far can you push it responsibly? When does th balance between safety and performance get out of whack?
You won’t have any issues with the I-5. It is a horse. Now… if you shortened it and made it minimum diameter and put a P or Q in it? That is deep water.
She’ll hold any certified 98mm you have enough shekels for 8)
JW
PS – Don’t use Elmer’s Glue on this one
Chris LaPanse
And these are the areas were I think the “how hard should you push it on a cert flight” comes into play. While pushing the envlope is certainly part of the fun in our hobby, how far can you push it responsibly? When does th balance between safety and performance get out of whack?
You won’t have any issues with the I-5. It is a horse. Now… if you shortened it and made it minimum diameter and put a P or Q in it? That is deep water.
She’ll hold any certified 98mm you have enough shekels for 8)
JW
PS – Don’t use Elmer’s Glue on this one
It’s certainly a great rocket. Mine isn’t an I-5, but it’s pretty close to one, and it’s done just shy of 20k twice, and it’s been supersonic 4 times. Rock solid every time. I’ll really push it (28k or so) at Mayhem this year, and we’ll see how that goes…
Bruce R. Schaefer
John A. Wilke
Steve Jensen
Chris LaPanse
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