Launchpad Rod is Curved

[burritoman1]

I built a midpower launchpad so that my rocket would have enough guide length. However, the only rod with the right dimensions (3/16in) had a big curve in the middle, probably 20-30 degrees from being straight. After a half hour of hammering, i was able to bring it down to about 5-10 degrees from end to end. I was wondering if this kind of curve would cause the launch lug to get caught on the rod, or signifcantly affect the flight profile of the rocket. I was planning to tilt the pad about 10 degrees to counter wind anyways, so it would be lovely if the curve would be able to do that instead. Thanks.

 

[neil_w]

I would absolutely not launch with a curved rod. Nosirree. Must be straight.

When you say "midpower", what sort of rockets and motors are you talking about? Normally I would think of a 3/16" rod as a low-power rod (although on the higher end of low power, stuff in the C-D-E motor range.

True midpower rockets typically fly off 1/4" rods, or more likely, rails.

 

[Antares JS]

I was wondering if this kind of curve would cause the launch lug to get caught on the rod...

You'll have to slide a rocket down onto the pad and check that answer for yourself. It depends on the length and spacing of the lugs.

or signifcantly affect the flight profile of the rocket.

Yes it will. I wouldn't try it, personally.

 

[burritoman1]

I would absolutely not launch with a curved rod. Nosirree. Must be straight.

When you say "midpower", what sort of rockets and motors are you talking about? Normally I would think of a 3/16" rod as a low-power rod (although on the higher end of low power, stuff in the C-D-E motor range.

True midpower rockets typically fly off 1/4" rods, or more likely, rails.

I was thinking of launching Es and lower F engines, although it seems I will just use a 1/4 rod instead. Is it possible to use 1/4 lugs on 3/16 rods? Because my local club refuses to use 1/4 rods.

 

[Antares JS]

I was thinking of launching Es and lower F engines, although it seems I will just use a 1/4 rod instead. Is it possible to use 1/4 lugs on 3/16 rods? Because my local club refuses to use 1/4 rods.

Possible, yes. Advisable, no. A thicker rod is stiffer and won't whip so much under a powerful motor. If your club literally has no 1/4" rods, just get yourself an Estes Porta-Pad E and bring it with you to the field to use.

Edit: or ditch the lugs and use rail buttons.

 

[neil_w]

I was thinking of launching Es and lower F engines, although it seems I will just use a 1/4 rod instead. Is it possible to use 1/4 lugs on 3/16 rods? Because my local club refuses to use 1/4 rods.

Yes, you can use 1/4 lugs on 3/16 rods, no problem. The better question is whether the rocket is suited to a 3/16" rod. What sort of rockets are we talking about?

I don't know what the exact cut-off would be, but I would say that once you get somewhere in the range of 10 oz for the rocket you should probably be on a 1/4" rod or a rail. Does your club have rails?

 

[burritoman1]

Yes, you can use 1/4 lugs on 3/16 rods, no problem. The better question is whether the rocket is suited to a 3/16" rod. What sort of rockets are we talking about?

I don't know what the exact cut-off would be, but I would say that once you get somewhere in the range of 10 oz for the rocket you should probably be on a 1/4" rod or a rail. Does your club have rails?

The rocket goes over 10oz on large engines, and under on smaller ones. They do have rails, but i was hoping to launch at home from my own pad, and a rail is probably overkill for the weight.

 

[neil_w]

The rocket goes over 10oz on large engines, and under on smaller ones. They do have rails, but i was hoping to launch at home from my own pad, and a rail is probably overkill for the weight.

A rail isn't really ever overkill per se (more rigid is always better), but a 1/4" rod would certainly be fine for rockets like that. It would be (I think?) in a grey area for 3/16" rods, but again I don't know what an exact weight cutoff would be. I would probably not fly an F off a 3/16" rod at that weight.

Maybe someone else can weigh in with more concrete info.

 

[lakeroadster]

I built a midpower launchpad so that my rocket would have enough guide length. However, the only rod with the right dimensions (3/16in) had a big curve in the middle, probably 20-30 degrees from being straight. After a half hour of hammering, i was able to bring it down to about 5-10 degrees from end to end.

Hammering? Simply bend it so it is straight. I think you are over thinking this.

 

[Alan15578]

Hammering? Simply bend it so it is straight. I think you are over thinking this.

Our first club launch racks had no pivots. We just bent the 1/8 inch SS rods at the base. After each club lauch, I would hammer the end straight. This worked fine, except that sometimes people would insert the wrong end into the clamp at the next launch. Even worse, some young rocketeers did not have the strength to bend the rod near the base, so they would grab the rod higher up and bend a long curve into the rod that was much more difficult to straighten.

 

[kuririn]

Our first club launch racks had no pivots. We just bent the 1/8 inch SS rods at the base.

Wouldn't it have been better to shim the legs of the launch racks? As many sheets of wood or bricks to achieve the desired deflection?

 

[lakeroadster]

Our first club launch racks had no pivots. We just bent the 1/8 inch SS rods at the base. After each club lauch, I would hammer the end straight. This worked fine, except that sometimes people would insert the wrong end into the clamp at the next launch. Even worse, some young rocketeers did not have the strength to bend the rod near the base, so they would grab the rod higher up and bend a long curve into the rod that was much more difficult to straighten.

What's your point? Do stupid stuff... win stupid prizes?

You can take a cordless drill, and drill holes in a 2x4 sawhorse at different angles, and that makes a great launch pad.

 

[jrap330]

I built a midpower launchpad so that my rocket would have enough guide length. However, the only rod with the right dimensions (3/16in) had a big curve in the middle, probably 20-30 degrees from being straight. After a half hour of hammering, i was able to bring it down to about 5-10 degrees from end to end. I was wondering if this kind of curve would cause the launch lug to get caught on the rod, or signifcantly affect the flight profile of the rocket. I was planning to tilt the pad about 10 degrees to counter wind anyways, so it would be lovely if the curve would be able to do that instead. Thanks.

Rods are NOT expensive, a whole discussion back a few months....check your local Hardware or Home Depot, Lowes. trying to bent anything back straight , as I found out is almost impossible. And concur 14 lug on 3/16 is a non issue.

 

[Alan15578]

What's your point? Do stupid stuff... win stupid prizes?

You can take a cordless drill, and drill holes in a 2x4 sawhorse at different angles, and that makes a great launch pad.

The point was hammering to straighten rods. The club launch system was designed and built by our first club president. Too much stupid stuff to describe here.

Cordless drills were not common in the 60's, and I would not advise drilling through the asbestos blast pads...

 

[Five]

I built a midpower launchpad so that my rocket would have enough guide length. However, the only rod with the right dimensions (3/16in) had a big curve in the middle, probably 20-30 degrees from being straight. After a half hour of hammering, i was able to bring it down to about 5-10 degrees from end to end. I was wondering if this kind of curve would cause the launch lug to get caught on the rod, or signifcantly affect the flight profile of the rocket. I was planning to tilt the pad about 10 degrees to counter wind anyways, so it would be lovely if the curve would be able to do that instead. Thanks.

Yes it will affect it,”big time”.
Here’s some pics. The third pic is the rocket getting stuck on the rod and the ejection charge shooting the nose cone off.

 

[Nytrunner]

They do have rails, but i was hoping to launch at home from my own pad, and a rail is probably overkill for the weight.

I put 1/4" lugs on one side and 1010 buttons on the other. Fly anywhere with that setup

 

[Five]

I put 1/4" lugs on one side and 1010 buttons on the other. Fly anywhere with that setup

I fid the same set up with my super DX3

 

[Cape Byron]

Cordless drills were not common in the 60's, and I would not advise drilling through the asbestos blast pads...

Well there's a problem...

 

[Five]

I was thinking of launching Es and lower F engines, although it seems I will just use a 1/4 rod instead. Is it possible to use 1/4 lugs on 3/16 rods? Because my local club refuses to use 1/4 rods.

Since your club refuses to use 1/4 rods. If i were in your shoes i might want to think about parting ways. Limiting your rockets to only a rod 3/16 rocket, would eventually get boring. Thats my personal look on it. Everyone is different when it comes to what excites them.

 

[Ronz Rocketz]

I bought a 48" 3/16 rod at Home Depot but it was the last one and had a couple bends. I tried straightending in my vise grip. Decided was too futile and bought a straighter one instead.

 

[lakeroadster]

The point was hammering to straighten rods. The club launch system was designed and built by our first club president. Too much stupid stuff to describe here.

Cordless drills were not common in the 60's, and I would not advise drilling through the asbestos blast pads...

Drilling holes in asbestos blast pads?

As far as cordless drills... geeze.... really? Have you seen the launch arrangements most clubs use that are made out of wood? That's what I was referring to. Drill holes into the wood at different angles in your shop before you leave for the launch site.

Although the titling mechanism isn't really rocket science.

 

[Woody's Workshop]

I have several old rods, all not in real great shape going on 40+ years.
I got 5, 1/8" two piece and 3, 3/16" two piece Estes's launch rods from Hobby Lobby online a couple months back.
Was checking them out again this weekend and see they went up a bit for the new year.
$4 for an 1/8" and $7 for a 3/16". Still a good price compared to everywhere else for the Estes Rods.

 

[BABAR]

Can also get creative with removable launch inserts that have buttons on them. Slide a dowel into the lug, screw on one end to hold it, a 80/20 button on the other end. Let’s you fly lug rockets with rails when needed.

 

[JimByrne]

Keep shopping for straight rods--I had to go to several stores but found 1/4", 3/16" & 1/8" and store them in a 1/2" PVC tube when not in use, so they don't get bent during transport. I also built a launch stand that will hold all three sizes.