Level 2 Project? Now level 2 kit!

[JohnK]

Here's a thought:

Leave the piston out. If it's oval now and you get a non-oval one, your rocket or your piston could go oval later, making things difficult again. If you rely on self-conforming recovery protection (ie: Nomex chute protectors or wadding), then you never have to worry about the problem.

[grin]

--JohnK.

 

[MaverickLV]

Thanks for the advice John but my father is a firm believer in stock built kits and he wants to build this one as directed. Also, we did get two 30" long shock cord protectors and slid them onto the piston strap for added protection.

As for PML, they have been good to me as usual. Andy in the tech service department really comes through for me in most cases. After sending the e-mail last night, I recieved his response today and he is sending me a new piston. All I have to do is cut the strap below the piston and add the new one, not too difficult.

 

[MaverickLV]

What the....

Ok guys, I know there were like two or three more replies after the one above. They had to do with "stock built kits" and piston problems. I believe they were posted by JohnK and someone else-please forgive me, I forgot who you are- but now those two posts along with a reply to them by me are gone! They were here last night, but now they're gone?

Dave

 

[rstaff3]

The Rocketry Forum's server was hacked and the messages that were posted between the last backup and the hack attack were lost. One or more from me

Also there were problems yesterday and today which kept posts from being posted.

 

[MaverickLV]

Oh, ok, thanks for that clarification.

Now JohnK, after thinking long and hard about these pistons, I am starting to defect to your side of "the force." Lets say that I would cut off the pistons. I am not saying definitely that I will, but I might. How would you, or anyone else, recommend I attach the 15' section of tubular nylon to the piston strap. I guess I could just tie it to a quick link and tie the tubular to that link as well, but would the know hold up? even with a little dab of epoxy? I don't know anyone who would sew it for me, but I am open to any other suggestions.

Dave

 

[rstaff3]

There have been several threads on rmr (maybe it was ROL?) and an article in HPR mag regarding knots. I don't have the references at hand, but from what I remember knots work great if you know the right ones for the right job. There are different knots for flat vs. tubular material. I'll look aroung and see what I find.

I make loops in my tubular nylon with a method presented in HPR Mag, written by the folks at Giant Leap. Basically you fold the end over so there is ~ 1 1/2 - 2' overlap. More or less depending on the material size. Be careful to leave enough loop. You then wrap the overlap tightly with cloth fishing line, making at least 2 passes back and forth. I guess any thin twine will work but make sure it is not plastic/nylon based. You then soak the overlapped area and twine in epoxy. Again, don't get epoxy on the loop. This is quick and dirty and seems to work well.

Finally, I like quick links on everything so I can replace chutes, shock cords, etc. I'm a cheapskate so I reuse chutes, and in a few cases shock cords, from rocket to rocket.

 

[kgholloway]

Dave,

The Giantleap method should work alright. For what it's worth it's a variation on "whipping a line" that was used on square rigged sailing ships. See Chapman's "Knots And Splices" for more information.

For tubular nylon I use heavy cotton thread to sew loops. I fold over the nylon so as to leave a loop of the size I want with at least 6" of the TN folded back upon itself. I then use upholstery needles and cotton thread, they're available from JoAnn fabrics, to sew a couple of boxes & X's in the TN. Think of a square with lines running from corner to corner. Two or three of these boxes results in a loop that's almost as strong as the TN itself. I then use quicklinks to connect everything up.

Ken Holloway, NAR #78336, L-1

 

[MaverickLV]

Hey Guys,
After reading your opinion's and after talking to a member at my local club we have decided, that if we do remove the pistons, we will fold about 3" of the 3/4" wide piston strap back over itself, leaving a loop for a quicklink. Then we will have a local shoe cobbler sew a couple of boxes with X's inside the square. We may add a little dab of epoxy where the end of the strap meets the the rest of the TN. Also, after consideration my father and I will use the normal oval shaped quick links. Although I don't believe I brought this up in the thread we were also worried about the weakening of the strapping at the point where it loops over the quick link. Here, because it's oval shaped, it can bunch up. However, because the triangle type of quick link can cause even worse bunching up of the strap and the pointed end, we are going to use the oval type.

BTW- This past saturday was a bust. The launch was postponed until the 20th, this Sat., because of poor weather. Anyway, if I do launch T&L this Sat. I will let everyone know. Also, that member that I contacted for the info. is bringing his just finished two stage PML Quantum Leap. I contacted him again when I heard this and challenged him to a drag race.....he accepted!
OHHHHHHH YEAAAAAAAH !!!!!!!!

One last thing, I finaly got those pics developed of Eclipse construction and I will try and get some of them to Phil tonight if I have time.

Dave

 

[rstaff3]

Maverick,

Please let me know what the shoe dude charges to sew the loops. I never thought of that. If cheap enough, I'd prefer that to the GiantLeap method.

Thanks

 

[MaverickLV]

It may be awhile before we get around to having the loops sewn, but, Ed, that guy I contacted, said that it only cost him about $2 for two straps on his PML Amraam.

If the cost is greatly differed from Ed's then I will let you know.

Dave

 

[MaverickLV]

Here is a link to the pics that Phil posted on his site.

Rocket Pics

Thanks Phil

 

[MaverickLV]

This past Sat. the launch was a bust. It rained for over an hour and low clouds and high winds kept the flights down to a minimum. I did manage to fly my Mustang on a G35 and I actual got it back (that thing just won't die), my LOC Legacy on an F20 (went pretty high for its weight), G-Force on a G40, and my Mach Buster on an E15-7(didn't see it come down but found it later on). Basically, I didn't get to put up T&L so it will have to wait until may 11. As far as the Eclipse goes, dad and I have eveything done but mounting the altimeter switch (We'll do that tomorrow), mounting the LLs (this weekend), and cutting the pistons off (yeah, you got your wish JohnK). This Sat. we are going to the shoe cobbler guy to have him sew the loops.

One question for you guys: How long do you think the tubular nylon for eclipse should be? PML only gives us two 15' sections (one for the fore recovery, one aft). Is that enough?

Dave

BTW- How do you guys like the pics?

 

[MaverickLV]

We managed to get the altimeter switch on tonight. My dad and I have yet another question though. This may sound kind of stupid but is there anything wrong with "upgrading" the altimeter vent hole from 1/8" (what pml says) to 3/16" or larger? Is larger better? or not?

David

 

[PGerringer]

Hey dude...

About Mustangs: If you really want it to die, just give it to me. I seem to have a nack of killing Mustangs.

About the Pics: You know my opinion. Thumbs Up. I expect to see more

About the altimeter slot: I don't think it will be too bad making the alt vent larger. As long as the hole is not pointing directly at your altimeter you should be OK...

 

[MaverickLV]

About that Mustang, you have to know the background info. on this thing. It has about 20-25 flights on it. First I flew it on an E28T reload (my first ever reload), then on a bunch of F's and always got it back. Then, I went back to an E15 and what happens, it gets stuck in a tree, then on an E30 and it lands hard on concrete. I don't think it likes low altitudes. That landing broke off a fin and split the spiral open in the body. After some epoxy I flew it again but now it was in an "ugly as hell" state so I really didn't care if I lost it. So, since then I have been shoving G35's in it and it keeps coming back, in 20mph winds and while its raining. It landed 10ft from the tree line this past weekend. I kinda want to lose it cause if I do, dad says he'll get me a new one that will look much better, but, I really don't think it wants to be lost as long as I give it what it wants....POWER!

Dad is going to drill the vent hole in the airframe this weekend. We will probably make it 5/32" or 3/16". It is not in direct line with the altimeter. The air has to flow into the hole, around the 38mm tube with altimeter in it and through a slot in the tube.

We went to the shoe guy today and had him sew two loops in the piston straps for us. He did it right in front of us (no waiting) and for FREE. So, I guess he is kinda a sponsor now, ehh? Anyway, the pistons are gone and we have two shock cord protectors on the straps plus we will add a parachute protector for the main chute. We will just use "dog barf" for the drouge becaue there isn't much room. As far as attaching the 9/16" tubular nylon to the piston strap loop. Should we use a quick link or two, or just tie it right to the loop? Is 15' enough?

Dave

 

[Lee Reep]

Wasn't sure if you have loops in the tubular Kevlar, but I'd still use quick links. They make things so easy. Should you need to use the Kevlar cord in another rocket, then you can easily undo the quick links and move it. If you don't have loops in the tubular Kevlar, then you could tie the cord to the quick link, and epoxy the knot.

Make sure you tighten the quick links ... We have a Quaker Parrot that learned to open the doors on his cage. So, I put quick links on them. Two days later, he escaped from the cage. He learned to unthread them, and unthread them enough to get them off the bars. Now I turn them tight with pliers!

And I keep the pliers out of his reach ...

 

[PGerringer]

Very impressive with the Mustang Mav. All my crashes have been with the E15 too. Interesting huh? Well, luckily I am out of E12s, I was going to fly it on an F this weekend but the weather got bad so I didn't. I will let you know if your theory holds true.

 

[PGerringer]

OH! And Happy Birthday Mav!!!

 

[JohnK]

Of course, I got busy with other stuff and ended up ignoring the thread for a few weeks and missed the question...

I get my wife to sew the box stitch and "X" pattern on the folded-over loop. I use the "D" rings without any problems. bunching doesn't seem to occur as a problem.

On my Level 3 rocket, I used heavy-duty tubular nylon sewn the same way, with no "D" rings at all. just used the quick-link directly into the loop on the end of the line. The trick is to properly size the quick-link to the width of the line to minimize the bunching. I get more of a slight curve, rather than bunching, on my lines.

I don't see a need for epoxy on the ends of the tubular nylon. I just heat-seal the ends to keep them from fraying. Tubular kevlar is a different story, however. I used knots for the tubular kevlar bridle inside my Level 3 rocket and a slight dab of epoxy or CA to keep the fraying down to a minimum. I used a three-point system for the bridle: Two forged eye-bolts (no gap to unbend) on the forward centering ring and a third eye-bolt in the forward bulkhead of the motor itself. Bridle anchored at the ends to the outside two eye-bolts and slipped through the motor eye-bolt for the shock line to attach to a quick-link. Provided extra safety for the motor, helping to make sure it stayed in the rocket after burnout. Future flights will probably add a second bridle in parallel to the first bridle to provide a level of redundancy.

Of course, you're not talking about a big Level 3 rocket, you're talking about a Level 2. You can get by with much less complexity. I think you're doing fine from what I've read so far. The epoxy will work, just isn't how I do it. It should be just as reliable. Just don't forget to use some sort of heat protection over the shock line or its anchor. As someone else has mentioned, Giant Leap makes good ones.

--JohnK.

 

[MaverickLV]

Hey Guys,
Sorry its been awhile since I posted anything but I have been busy with getting ready for finals in a couple weeks and some other school stuff. Actually, I am preparing a rocketry demostration for the sixth grade class. The annual rocketry unit that I started a year or so back is still around and will probably be part of the sixth grade lessons for years to come. This year, I am going into more depth in my presentation and it takes a little bit more planning than I thought. Also this year, I am going to launch my Mustang on an F20, just to show the kids the POWER of mid power rocketry. I hope to write an article for Sport Rocketry on this class and maybe they will publish it, who knows!

Anywho, dad finished up the eclipse (tied TN, attached LL's, etc) and we are going to try and prime it this weekend. I think I have the paint scheme ironed out too. I am going to paint it (me, not dad, because he just doesn't have time) that mirage purple/green stuff that I have heard sooooo much about but...
There's more! I am going to airbrush on red and yellow flames coming down from the NC maybe 8" of the fore recovery airframe.
It should look really cool!

Dave

 

[MaverickLV]

Oh yeah, one more thing, since Phil mentioned my BDay, I guess I should tell ya what I got.
-Rocksim 5.0 (all I had was the demo version before)
-Cash for motors for T&L
-Permission to modify my father's Patriot for Dual Deploy (that's my next project, we hope to order the parts for the alt bay this weekend or next week and begin construction by next weekend)

 

[Austin]

DANG Mav...

You cleaned up!!! Good for you!

Carl