Launch Lug Q

Discussion in 'Low Power Rocketry (LPR)' started by womblegs, Oct 6, 2003.

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  1. Oct 6, 2003 #1

    womblegs

    womblegs

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    I've just got back into this after about 10 years! Found a few of my old rockets kicking around and thought it would be fun to give it another go. So pleased to see so much info available now.

    My question.... I need a new lauch rod and I am thinking about scratch building some bigger (poss cluster) stuff. I though a 5mm rod would be better for this. Is there any reason why I can't convert my old (3mm) rockets to use the bigger rod?

    Gareth
     
  2. Oct 6, 2003 #2

    BlueNinja

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    First of all, welcome to the Forum! I'm sure you'll like it here.



    You should be able to convert your old rockets to 5mm, but it would aso be a good idea to leave the old lug on.





    Blue
     
  3. Oct 6, 2003 #3

    jflis

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    Welcome to the forum! :)

    I would recommend that you use a lug that is appropriate to the rocket and use 2 different rods, as necessary.

    jim
     
  4. Oct 6, 2003 #4

    rstaff3

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    My recommentdation is to lose the lugs and get railbuttons (and a rail, of course, unless your friendly local club has 'em ;))

    http://www.railbuttons.com/rb/
     
  5. Oct 6, 2003 #5

    womblegs

    womblegs

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    Thanks guys for the warm welcome, as well as the good advice.

    Just been trying to get some kit back together. I've found a supply of tubes, cones and stuff (www.apollo11.co.uk - and Tony only lives 10 minutes away from me!).

    Got a few rockets repaired (from 10 years ago!) and a couple on the work bench. Just don't think we'll have the weather for a launch for a while. :(

    Another Q... do engines expire? I've test fired one 10yr old estes C6 and it went off fine.

    Gareth
     
  6. Oct 6, 2003 #6

    sandman

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    womblegs,

    A very big WELCOME to our fourm.

    Please be kind enough to complete your profile so the rest of us know where you are from...and the bithdays are always a nice treat too!

    Apparently since you know and live close to Tony I assume you are in the UK.

    No BP (black powder) motors, the Estes/Quest type do not expire but, they are susseptable to freeze/thaw cycles. This can cause internal cracks, seperation from the casing...all manner of troubkle.

    If they are properly stored and have been maintained at a fairly stable temperature they will last indefinitely.

    sandman
     
  7. Oct 6, 2003 #7

    Ryan S.

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    Welcome! I always use the biggest rod possible. This is because it is stiffer so resists bending and has less whip when the rocket leaves it
     
  8. Oct 6, 2003 #8

    arthur dent

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    Great to see another Brit on the forum,i bet there's more rockets available now than there was 10 years ago.You'r lucky being so near to tony at apollo 11,have you checked out DEEPSKY ROCKET SUPPLIES at www.modelrockets.co.uk
    Your right about the weather,im watching the trees bend as i type this:mad:
     
  9. Oct 6, 2003 #9

    Micromeister

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    I still have my "OLD" estes two piece C-Rail, It's been so long I don't remember why I stopped using it, looks like it needs something about 1/16" to slip down the slot and maybe about the same thickness to clear the thickness of the alum. Is this a candidate for "rail buttons". could someone explain what they are and/or how that attach and what makes them better then a tubular launch lug?
     
  10. Oct 6, 2003 #10

    Mike

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    Great to have another Brit on the forum, there's about 5 or 6 of us who post frequently now. Tony's real nice and you're very lucky living so close.

    You might like to check out and maybe join UKRA the United Kingdom Rocketry Association at http://www.ukra.org also have a look at a few local clubs, SERFS fly in Wiltshire and Hampshire, i think there's another club in north wales too.

    HTH and keep posting!
     
  11. Oct 6, 2003 #11

    maddogdelta

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  12. Oct 6, 2003 #12

    maddogdelta

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  13. Oct 7, 2003 #13

    womblegs

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    Thanks again for the warm welcome guys.
    Yes, I have noticed a lot of new kits available although I'm not hugely interested in them - I intend to make full use of Tony at Apollo 11 and get on with some scratch built stuff. Got some interesting ideas!
    Why do a lot of you guys still buy the kits? With the exception of some very fancy kits available from Fliskits (sp????) they really is little need for them. I've found so many estes plans available online if you really wanted to build one.

    Arthur Dent - Love the nick! "Is there any tea on this spaceship?"
    Hmmm, lot of time on my hands, maybe a scratch built Heart Of Gold could be a way to go!

    Gareth
     
  14. Oct 7, 2003 #14

    lalligood

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    I think Matt Stum's website explains exactly what rail buttons are & how they work. I've only used them on MPR/HPRs so far but I've hear they can be used on LPRs. The main benefits of rail buttons are less drag than launch lugs & they are impossible to cause the rocket to bind on the rail (unless the buttons were WAY off!) Also with the rail being more rigid than a rod, it all but eliminates any chance of "rod whip"...or so the theory (& debate) goes.
     
  15. Oct 7, 2003 #15

    rstaff3

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    micro, sorry I missed your question....but lalligood gave the best reference. I use them on my hpr and mpr rockets and on many lpr rockets from BT-60 on up, although I often add an appropriate set of lugs also. They not only eliminate rod whip due to the boost, but also due to wind loading. Perfect for a Mean Machine! This weekend at the Sod Farm my little jet-plane style rocket really was getting whipped around. Wish I had an extra set, but I gave them away at the previous launch.

    One thing I have liked at NARHAMS is that when the pads are busy, I take my rail to our 'away cell' and can launch on every round. Of course you either need a club with rails or you have to get one of your own. If you rely on the club facilities, I've run into the other case where there are fewer rails and you may have to wait longer. Having your own solves this too - just move it to any open pad. Nothing like a teeny rocket going off the K-L pads :D
     
  16. Oct 7, 2003 #16

    powderburner

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    ----------
    lalligood said:
    "The main benefits of rail buttons are less drag than launch lugs"
    ----------

    I agree that rails offer a lot more stiffness and structural support than rods, and that buttons are essential for safe launch of mid- and high-power rockets.
    But I doubt you can convince me that those big fat buttons cause LESS drag than a little Estes launch lug on a low power rocket. For low power, buttons are extreme overkill (IMHO). If you want low drag, use a tower.
     
  17. Oct 7, 2003 #17

    trogdor

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    I would agree with powderburner with the drag thing (I'm no NAR contest guy though...) but I thought i read somewhere that the lug's major drag component had to do with its specific shape.... maybe that it's a tube... ???
     
  18. Oct 7, 2003 #18

    Micromeister

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    Thanks guys:
    That's pretty much what I assumed, sounds like somthing to consider for LMR's and Clusters. I looked at these things before, just don't understand how they attach well to the model. I guess I could adapt something to use my Old 36" estes C-Rail, I think this thing was used my Saturn-V lugs with a stand-off. Do the bigger buttons attach the same way glue or epoxy in place?
     
  19. Oct 7, 2003 #19

    sandman

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    Micro,

    The bigger rail buttons usually attach with a screw threaded into a centering ring or with a T-nut inside the body tube.

    I think you could make up tiny rail buttons out of some washers or maybe turn them in a tiny lathe like a Unimat.

    Carl got some really really tiny ones for micromaxx that were actually from an HO scale slot car...I think...

    Carl? where did you get those?

    sandman
     
  20. Oct 7, 2003 #20

    rstaff3

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    The 'standard' black sky-sized buttons (=the smaller size on railbuttons,com) work fine on Estes tubes. Just drill the proper hole, test fit the button, remove it and add a drop of CA, reinsert it, and you're done. Put one near the bottom of the rocket and the other between the CP and CG (I've heard arguements on CG and CP but I haven't found it makes much difference). Some examples of lpr kits that I have these on: Mean Machine, Launch Pad Rapier, Estes Atlas, Big Daddy.

    I agree the weight and drag prolly make these sub-optimal for performance on lpr models. For the sport flier they are great.
     
  21. Oct 7, 2003 #21

    WiK

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    Or, a new find of mine, use Pop Lugs! They work on a standard launch rod, all you have to do is put a bit of masking tape on the top! The lug stays with the rocket when its on the rod, and guides it, but as soon as it hits the tape, it pops off letting the rocket continue with out it!
     
  22. Oct 7, 2003 #22

    Micromeister

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  23. Oct 7, 2003 #23

    WiK

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    Micro: I did say
    MINE, meaning I've only just found them! I know they've been around for years! I know they are lower drag than towers, but since he asked about launch lugs, and towers aren't avaliable here in the UK, i thought I'd tell him that

    A heart of gold model??? How on earth will you build that? Perhaps a miniture working improbability drive?? Oh, and welcome to TRF. Good to see the Brit rocket community represnting itself here :D
     
  24. Oct 7, 2003 #24

    womblegs

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    I've done a fair bit of aero modeling over the years, and my father does loads now - having recently discovered R/C.

    I thought rather than using tubes and cones maybe a balsa rib cage with some iron on covering.

    Maybe a bit ambitious but what the hey! Might be a little on the heavy size, so a D engine cluster was a thought.

    Has anyone in the UK made igniters for A-D engines? Never been happy with the Estes ones. I'm making my new launch controller so I thought I may try igniters too.

    Gareth
     
  25. Oct 7, 2003 #25

    arthur dent

    arthur dent

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    womblegs
    I have built some great scratch rockets using apollo 11's parts.You've got me thinking now,perhaps Hotblack Desiatos stunt ship or perhaps a frogstar fighter:D Mind you i hav'nt a clue what they look like LOL
     
  26. Oct 7, 2003 #26

    womblegs

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    Think the tv show has a couple of shots of the stunt ship. Will look at the dvd in a minute.
     
  27. Oct 7, 2003 #27

    womblegs

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    Shot 1
     
  28. Oct 7, 2003 #28

    womblegs

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    Shot 2
     
  29. Oct 7, 2003 #29

    womblegs

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    Shot 3
     
  30. Oct 7, 2003 #30

    cydermaster

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    The Disaster Area stunt ship? There hasn't been a paint invented yet, thats black enough to build that. Man that ship was black!!!

    :D

    Welcome to the forum womblegs/Gareth - more Brits the better! BTW. Like the screen name - which was your fave? Mine was Tobermory.
     

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