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Any problem with very long (e.g., 7") launch lugs?

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neil_w

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Is there any critical reason not to use a long launch lug, like around 7"? We're talking 3/16" lug here. I know it'll be a bit more friction off the rod, but is it really a problem? I'm considering it as an alternative to having to thread a rod through a hidden maze inside the BT.
 

K'Tesh

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I'd have to say... "No"

I've seen Fatboy's steampunked FlisKits A.C.M.E. Spitfire that used a long launch lug to conceal that it was a launch lug (as a pipe).



What's more... you've seen it too. You posted in the thread talking about it. :wink:
 
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neil_w

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I remember that rocket, didn't remember the launch lug. I can hardly remember what I had for dinner an hour ago.

That lug is awesome (as is the rest of the rocket).
 

Rocketjunkie

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Is there any critical reason not to use a long launch lug, like around 7"? We're talking 3/16" lug here. I know it'll be a bit more friction off the rod, but is it really a problem? I'm considering it as an alternative to having to thread a rod through a hidden maze inside the BT.
Just make it loose, like using a 1/4" lug for a 3/16" rod. This way slight bends in the rod won't cause binding.
 

Zeus-cat

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Binding would be the issue I would be concerned about.
 

TheTellurian

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I've used full length internal launch lugs in all of my Silver Rockets, generally 22" long. Never had a hitch. Make them oversized and always check that the rocket slides freely up and down the rod.


Richard
 

rstaff3

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I've used full length internal launch lugs in all of my Silver Rockets, generally 22" long. Never had a hitch. Make them oversized and always check that the rocket slides freely up and down the rod.


Richard
This is my experience too.
 

rstaff3

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Because I'm lazy, I have used a lot of whole First Fire tubes as 1/4" lugs. When not lazy, I cut them down and bevel the edges. But the raw tube works well for 1/4" rods and, if the rocket specs allow, 3/16" too.
 

Micromeister

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Is there any critical reason not to use a long launch lug, like around 7"? We're talking 3/16" lug here. I know it'll be a bit more friction off the rod, but is it really a problem? I'm considering it as an alternative to having to thread a rod through a hidden maze inside the BT.
Like most of the others posting, I've used oversize Launch Lugs on many Upscale Models particularly on internal lugs that pass through a long section of the Main body. My 3X UpScale Laser-X has a 20" x 5/16" dia. internal lug. Used on 1/4" rods has never been a problem.

Always the same advise! Always oversize the lugs to avoid binding.

To be perfectly honest I always perfer to use a pair of much smaller lugs than a single long lug. but as Long as binding is prevented it shouldn't be a problem at all.
 

neil_w

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I'm still debating best approach here. Switching to 1/4" lug at this point would be inconvenient, but not out of the question. I'm just concerned that if I have two small lugs about 5" apart, with area between them hidden, it'll be a chore to thread the rod. Maybe it's not really so bad, hard to guess at this point.

I have an alternate approach that I can try as well, but it brings its own problems.
 

hornet driver

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Almost all of my builds use long single lugs. I have had no problems with them and in fact I think they tend to dampen rod whip. Personally I don't care for the appearance of lugs and a long one can be worked into the design so it doesn't stand out as much--at least not as a lug. All of my Interceptors use a full length square lug on the spine and for internal lugs you just about have to use single long units to avoid alignment problems and binding.As far as the problem of binding goes, I oversize the lug just a bit so it slides smoothly but you just can't beat a nice true rod to solve that problem. I do like to polish my rod with a handful of wax paper. It keeps the oxidation down and smooths out the surface.--H
 

rharshberger

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Almost all of my builds use long single lugs. I have had no problems with them and in fact I think they tend to dampen rod whip. Personally I don't care for the appearance of lugs and a long one can be worked into the design so it doesn't stand out as much--at least not as a lug. All of my Interceptors use a full length square lug on the spine and for internal lugs you just about have to use single long units to avoid alignment problems and binding.As far as the problem of binding goes, I oversize the lug just a bit so it slides smoothly but you just can't beat a nice true rod to solve that problem. I do like to polish my rod with a handful of wax paper. It keeps the oxidation down and smooths out the surface.--H
Last two sentences taken out of context are interesting.....
 

dave carver

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Think on it for a few minutes, there can only be two points of contact if torqued and one point if the lug is in full contact with the rod, an unlikely occurrence. When launching the rocket will turn away from the thrust and then the contact point will be where the rocket makes contact with the top and bottom of the lug. It's also possible, in a perfect world, everything will line up and the rod will pass through the center of the lug...in a perfect world... ;)
 

Flyfalcons

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True, but that also assumes a perfectly straight launch rod.
 

dave carver

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True, but that also assumes a perfectly straight launch rod.

One would hope so. That reason is why I bought O1 tool steel drill blank rods from McMaster-Carr. In keeping with MicroMeister's suggestions I actually got the three rods a few thousandths undersized, something you can do with ground drill blanks. They come 6' long allowing you to cut them to any length. Call them to make sure what you want is stored in the same place or pay double shipping charges.
 
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