But on the other hand- a longer rocket will have launch lugs farther apart and the forward launch lug will clear the end of the rod at less distance traveled than for the short rocket. So for this reason it would seem that a longer rod would be required.
we are planning B6-4 for our first flight and c6-5 for the restMy 3/16 launch rod I use for E9's is 38 inches long. Standard hobby shop
rod, K & S I believe is the manufacturer.
This is excellent advice. I doubt that you can even find 1/8" rod in 48" lengths, though, so that probably won't be an issue.Humma,
If you have any doubts about the launch rod being long enough, then it is probably time for you to get a 4 foot rod for your collection of range eqpt
You can find round rod (also called cold-rolled steel) at your local hardware store (Home Depot, Lowes, Sutherlands, etc) in a bin with short lengths of angle stock, all-thread, and other metal products. They will likely have it in 3/16th diam and 1/4 (and bigger), and in lengths like 3, 4, and 6 feet. You may only feel the need for 3/16 right now but I would encourage you to go ahead with the 1/4 inch for bigger projects in the future.
I specifically recommend against getting a 4 foot length of 1/8th diam. It just gets too "whippy" and will be more dangerous than beneficial.
This is excellent advice. I doubt that you can even find 1/8" rod in 48" lengths, though, so that probably won't be an issue.
Oh that's right. Now that you mention it, I have seen them in that length. The cold-rolled type is the one to get. I must have been thinking about 1/8" rod in 6 foot (72") lengths. Awhile ago I was looking for 6' x 1/8" rods for some reason. Not easy to find, but with some digging you can find it. Even in stainless steel. It was powderburner, not me, who brought up the stiffness issue with longer lengths of thin rod. I think that would very likely be a problem with a 6' long, 1/8" diameter rod. Unless perhaps you get it in something like titanium.We buy them at Home Deopt for our standar club launch rack pads. 1/8" diameter by 4 foot long cold rolled steel. Not very whippy at all and they provide excellent guidance as the rockets build up speed so they can safely fly on their own.
(snip)... that diameter rod is appropriate for small lightweight rockets, but for anything more, and with motors that have more than C impulse, a larger rod is needed. One point of view is that it never hurts to use 3/16" lugs for all low power rockets regardless of mass.
I build ALL my birds with a minimum 3/16 launch lug and some of them are pretty small.I agree completely, and would even go a step further. I think all beginner rockets, especially "class-build" rockets, should be equipped with 3/16 or even 1/4 launch lugs.
I agree completely, and would even go a step further. I think all beginner rockets, especially "class-build" rockets, should be equipped with 3/16 or even 1/4 launch lugs.
The reason is that this class of rocket tends to get used under circumstances where school schedules are crucial and the flexibility is just not there to allow launch postponements on marginal weather days. Teachers just can't afford to mess up their whole week on the chance that tomorrow might be a better launch day. They have lesson plans to cover, they have their own schedules to keep, and most of them even have state and federal laws in their hair about completing a minimum set of subject units. Letting us come in and do a rocketry unit is disruptive enough, interrupting again and again for weather delays (when the weather looks fine to them) will quickly get you NOT invited back.
When I tell them that we will launch on Wednesday, and it is a little extra windy that day, I like it a whole bunch better if I am prepared with 1/4 inch launch lugs and 1/4 inch rods that are all four feet long, even for little rockets with 1/2A motors. I feel far safer proceeding with a class launch under such conditions. Otherwise, the launch might not happen at all.
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