Of "D" engines and launch lugs.

[Spacepirate R]

I was lucky to get an Estes Super Alpha with a balsa nose cone and I am planning on putting a 24mm mount in it. Should I put a 3/16 rod sized launch lug on it? I most likely will not launch it on anything larger than a D12.

 

[Rocketbuilder]

I would say put both an 1/8" and a 3/16" launch lug on it, one on each side of a fin. That way, you don't have to switchout the rod if you are launching it on a smaller engine, but you have the option of putting it on a larger rod if you're flying it on a heavier engine.
Plus, if you fly at a club, when somebody inevitably snags the last 1/8" rod you can put it on a 3/16".

 

[fyrwrxz]

+1 on the 3/16". Rod whip will be less for a heavier bird like this.

 

[C-57D]

Why bother with both a 1/8" lug and a 3/16" lug?

A 3/16" lug will work just fine for either size rod.

 

[Rocketbuilder]

Why bother with both a 1/8" lug and a 3/16" lug?

A 3/16" lug will work just fine for either size rod.

That's usually true, but it depends on how long the lug is. A lot of my rockets have relatively short launch lugs, so it is more important to put them on the right size rod.
You're right, though. I am a bit biased by my own experiences, which may be significantly different from others'.

 

[Bazookadale]

Why bother with both a 1/8" lug and a 3/16" lug?

A 3/16" lug will work just fine for either size rod.

I agree - I put over sized lugs on many of my rockets so I don't have to switch out rods too often. This sometimes results in an argument with a RSO who might tell me I can't fly a rocket with a 3/8" lug from a 1/4 inch rod - I've done this 100s of times with no problems

 

[rocketgeek101]

I would go with the 3/16" lug.

 

[Spacepirate R]

So I should go with the 3/16 lug then? I ask as then I have to go and get one.

 

[C-57D]

Honestly, unless you envision a shortage of 1/8" rods at your club launch, there's no need to switch to a 3/16" lug, just because you're going to fly on "D" motors. That, by itself, isn't going to make your model so much heavier.

 

[Rocketbuilder]

No, it won't make it that much heavier, but it will accelerate faster on a D12 than with, say, a B6 or a C6, so rod whip could potentially be an issue. (Though I'm not completely sure how big of a problem that would be.) Again, I am biased by my experiences; the club I fly at is Tripoli, so the majority of the pads are for MPR/HPR. There are still a fair number of LPR rods, but on days with larger turnouts, sometimes they get taken pretty quick. Other clubs may not have the same issue, though.

 

[Spacepirate R]

Wel, I don't have a club. Just me and my standard Estes launcher. I do have a 3/16 rod which I use with my Blue Ninja and Goblin (the Goblin has 3/16 lugs on it). Hmm. Didn't the original Goblin have just the 1/8 lugs?

 

[maricopasem]

Don't buy larger lugs. Just wrap a drinking straw in masking tape and you're good to go.

 

[powderburner]

Hmm. Didn't the original Goblin have just the 1/8 lugs?

IIRC, most of the kits that came out for the first "Mighty Ds" did indeed still use 1/8th launch rods---that is all we had back then. And we liked it.

Not to say it would not be a good idea to use a 3/16 lug and a 3/16 rod. This would be better in almost all cases, even if the rocket did still "work" with 1/8th gear.

And it is not difficult to find 3/16th rods in almost any community. Your local hardware store probably stocks it (they call it "round rod" and often have a bin full of steel rods, all-thread, angle stock, and other metal specialty products). Your local RC hobby shop probably carries a good assortment of "music wire" for making model airplane control linkages (this is better quality steel with a little heat treatment). Your local craft stores might even stock a little inventory of steel rod in these sizes. At any of these places, a three-foot length should only run a buck or two.

 

[Spacepirate R]

Oh, I have a 3/16 rod, I just don't have an extra 3/16 lug. I was just thinking that since the Super Alpha already has a 1/8 lug I'll just use that, but if launching it with D power on the thicker rod is that much better then I'll have to see when I can get the larger lug.

 

[powderburner]

Instead of waiting, you could make your own easily enough.

If you already have the rod, you have the "hard" part done. Roll a few layers of waxed paper around the launch rod (4-5-6 layers thick), then roll a strip of paper around the outside of the waxed paper. Add a few drops of CA between the layers of paper, and soak a light coat of CA onto the outside of the paper.

Cut to preferred length and attach to rocket.

 

[Rex R]

imo it looks better w/ a 3/16" lug .
rex

 

[Micromeister]

The general published Norm for D12's has always been 3/16" lugs.

As Fyrwrxz mentioned 3/16" rods will exhibit less rod whip on the usually heavier D powered rockets.

 

[hcmbanjo]

At a D engine I would go with the 3/16" lug.
For that matter, 2 and 3 engine 18mm cluster models have 3/16" lugs.
My models at the 2 foot tall level and above an 18mm engine would get the bigger lug.

Another thing to think about -
If the original sized Alpha (at 12.25") were scaled up, wouldn't the lug be larger too?

If you want it to look like an enlarged Alpha, (larger fins, nose cone and body tube diameter) the lug could also be sized up.