1/4" Launch Rod Metals????? Bendy vs Stiffer????

[4regt4]

Good to know!!! I'm pretty sure I've seen you launch rockets bigger than the Estes Doorknob and with E and F motors (and bigger?)

Were those "bigger" rockets with "bigger" motors I've seen launched off the Estes 1/4" 2-piece 59.5" launch rod? If so, that's good news for me!

Thanks - Paul

At Corvallis, I've been launching everything off of a heavy duty tripod. Depending on the size of the rocket, I switch out between a 3/16 solid rod I got at the local metals dealer (it rusts real bad), and the Estes 1/4" 2 piece. The rocket in my avatar pic here was launched at Corvallis last year off of that rod. It weighs 28oz w/o motor.

I don't know what the Estes rod is made of, but it is still mostly bright and shiny after 3 years of frequent use, just a touch of surface corrosion that I haven't bothered to wipe off. It might be a plating, or ???? Also it hasn't acquired any permanent bend, even after being packed in the car with other stuff put around it.

Hans.

 

[hball55]

When I used rods, 1/4” stainless steel worked for me.

 

[Paul Howard]

At Corvallis, I've been launching everything off of a heavy duty tripod. Depending on the size of the rocket, I switch out between a 3/16 solid rod I got at the local metals dealer (it rusts real bad), and the Estes 1/4" 2 piece. The rocket in my avatar pic here was launched at Corvallis last year off of that rod. It weighs 28oz w/o motor.

I don't know what the Estes rod is made of, but it is still mostly bright and shiny after 3 years of frequent use, just a touch of surface corrosion that I haven't bothered to wipe off. It might be a plating, or ???? Also it hasn't acquired any permanent bend, even after being packed in the car with other stuff put around it.

Hans.

Perfect!!! My Very Modified (and heavier than stock) Estes Doorknob weighs about half the weight of the rocket you mention. I do remember your Camera Tripod Launchpad.

Thanks! - Paul

 

[Paul Howard]

I use carbon arrow shafts for my FAI towers and it cleans easier than any metal rod.
You can find some high quality carbon pultrusions at kite stores like intothewind.com... get a couple 3 footers and an inner coupler for easy transport.
You can then fill each piece with epoxy to make it super stiff. I bet it would be much stiffer than metal.

Good to know and it's definately worth looking into!

Thanks! -Paul

 

[Daddyisabar]

So the bottom line is that if you are a good boy being careful and clean with your Estes two piece 1/4" rod you will be just fine. Estes rod used to launch Estes approved rockets! I like that. No naughtiness, no problems!

 

[SolarYellow]

I did do a little bit of sanding of the bottom of the top-piece with emery cloth on one of them at the joint to get a smoother travel of the launch lug to not have it hit a "bump" at that junction.

That's exactly what my post was about. I figured out that I was able to eliminate the bumps just by clocking the rods relative to each other, rather than having to sand anything.

 

[Blast it Tom!]

On my personal launch pad, one way that I combat rod whip is by not having the rod support the rocket. That really isn't possible with the club setups that I've seen.

If I had known about rails when I started back into this magnificent obsession, I most certainly would have gone with rails for the most part. But when possible, my rockets sit on their fins on my pad.

 

[4regt4]

So the bottom line is that if you are a good boy being careful and clean with your Estes two piece 1/4" rod you will be just fine. Estes rod used to launch Estes approved rockets! I like that. No naughtiness, no problems!

Except I've used my Estes 1/4" 2 piece rod for 3 years WITHOUT cleaning it, and it's still fairly shiny and almost totally devoid of corrosion.

Hans.

 

[bjphoenix]

The old dudes are soooo silly with thier outdated, obsolete, polished and uncool thick rods. Always looking for more stiffness to avoid the dreaded Rod whip.

My L1 rocket is from back in the days before rails so it has some big launch lugs on it. If I want to launch it again I have to add buttons.

The bigger decision will be 5 feet long vs 6 Feet Long.

Have you run sims of your rockets? You could determine if you get enough velocity off of the 5' rod. Be sure and consider how much length of rod goes into your launch pad and how much standoff distance you use, subtract those from the length you input in your sim.

 

[DirkTheDaring]

This is like a mini-engineering seminar. A couple of things jumped out. @DirkTheDaring pointed out that rod choice has multiple objectives. From the rust perspective you could get a 304 stainless. From the low-friction perspective, you'd have to find it in polished form ($$$, or poliish it yourself).

It's cool that @Blast it Tom! (and others) points out that we are after a material with high yield strength. That's how much force per area (psi in freedom units) it takes to permanently deform the rod. If we are more worried about deformation than corrosion, then the Chrome-Moly steels (4130 is a common type) might be chosen. And as pointed out above, you'd want it heat treated, not annealed. You can order it this way - its called 4130 HT. May require the polishing treatment.

If you want to enter the world of high-yield-strength AND corrosion resistant alloys you could try to find a rod in duplex stainless. Not sure how available this stuff is, and be prepared to trade your your left nut or you first-born to pay for it. But it nearly matches chrome-moly for yield strength and it is stainless.

I bought a 1/4 carbon steel rod at Lowes. I'll have to polish it after every launch. But it seems servicable. I'll probably use Boeing T9 anti-rust after each scotchbrite session. Let the T9 dry on them, then store in a pvc pipe.

Along the lines of stiffness, does anybody know of folks who use 2x1 (1020) extrusions for launch rails, rather than the 1x1 (1010) standard?

My left nut is worthless and there are certainly days when you can have my first born. But I digress...

 

[Daddyisabar]

Except I've used my Estes 1/4" 2 piece rod for 3 years WITHOUT cleaning it, and it's still fairly shiny and almost totally devoid of corrosion.

Hans.

Fantastic! I know some dudes who are like old school Prussian NCOs looking down the barrel of your black powder needle gun for cleanliness. They also chek out your reload casings after a field wash. With those cleanliness standards I might have to go AWOL!

 

[DirkTheDaring]

Crazy Train. Old thread here on the forum. You are supposed to go off the rails riding on the Crazy Train. But on this one I used lugs because they were easier to integrate into the design and looked better. At the RSO table it was obvious it lacked stiffness so I had to make sure it went off a long stiff rod. Clustered tractor motors solved the problem.

Thanks, I'll be sure to check it out. I'm very fond of oddrocs.

 

[Daddyisabar]

My L1 rocket is from back in the days before rails so it has some big launch lugs on it. If I want to launch it again I have to add buttons.

Have you run sims of your rockets? You could determine if you get enough velocity off of the 5' rod. Be sure and consider how much length of rod goes into your launch pad and how much standoff distance you use, subtract those from the length you input in your sim.

Come to the club located in Hartsel, Colorado. The Top Men old dudes are very understanding of rods and will let you use them. Party like it's 1999!

 

[Daddyisabar]

Thanks, I'll be sure to check it out. I'm very fond of oddrocs.

I like the tape on that HUGE stand off! Big standoffs on oddrocs and scale models are cool. Darn the rod whip! Get an absurdly long, thick and strong rod. Yes Mr. RSO. This oddroc abomination dosen't work on the almighty rail...

 

[RokitFlyr]

On my personal launch pad, one way that I combat rod whip is by not having the rod support the rocket. That really isn't possible with the club setups that I've seen.

If I had known about rails when I started back into this magnificent obsession, I most certainly would have gone with rails for the most part. But when possible, my rockets sit on their fins on my pad.

View attachment 682752

Doesn't that severely burn the bottom of the rocket?

 

[Blast it Tom!]

Doesn't that severely burn the bottom of the rocket?

No, there is a hole in that black cover and a blast plate at 45°, and the exhaust is ducted out the side.

 

[ReynoldsSlumber]

But when possible, my rockets sit on their fins on my pad.

Keeping in mind, for those not already in the know: don't do this with a fat-bottomed rocket with a recessed engine. Bernoulli lock, suctioned to the blast plate! BBQed the interior posterior of a Saturn V that way once.

 

[Blast it Tom!]

Keeping in mind, for those not already in the know: don't do this with a fat-bottomed rocket with a recessed engine. Bernoulli lock, suctioned to the blast plate! BBQed the interior posterior of a Saturn V that way once.

Again, you do not want to launch any rocket with the motor nozzle in close proximity to a flat plate, as he says, due to Bernoulli lock. My private launch pad has an opening below the rocket that's at least the diameter of the rocket, often moreso. And the blast plate is at a 45° angle, so that the launch gases are ducted out the side... no lock!

 

[WizardOfBoz]

Very nice Mercury, and a cool launch pad, @Blast it Tom!

 

[tsmith1315]

And the blast plate is at a 45° angle, so that the launch gases are ducted out the side... no lock!

Every time I see this, I tell myself to build one!!!

 

[Blast it Tom!]

Every time I see this, I tell myself to build one!!!

Yeah, I love that picture!

 

[Peter Kay]

I wished there were options that had the polished/chrome finish like the Estes rods.

 

[SolarYellow]

316 rods are available from Zoro.com. Look up the item you want on Grainger, then search for the item number at Zoro.

 

[Paul Howard]

Again, you do not want to launch any rocket with the motor nozzle in close proximity to a flat plate, as he says, due to Bernoulli lock. My private launch pad has an opening below the rocket that's at least the diameter of the rocket, often moreso. And the blast plate is at a 45° angle, so that the launch gases are ducted out the side... no lock!

View attachment 682948

Wow, Cool Stuff!!!

 

[mjennings]

Great engineering discussion! I keep my rods in a sealed PVC pipe with threaded ends. WD-40 is great for cleaning rods, solvents mixed in with the oils, but I like something more straight oil, maybe with a little silicone lube mixed in for storage. Also easier to clean rods after a launch than before!

 

[sr205347d]

but I like something more straight oil

I was using air-tool oil, which slowed the corrosion, but WD-40 works much better.

 

[bjphoenix]

WD-40 is great for cleaning rods, solvents mixed in with the oils, but I like something more straight oil, maybe with a little silicone lube mixed in for storage.

WD40 is really not very good for long term lubrication or for long term protection. Even motor oil isn't very good for long term protection. I had a set of feeler gauges in my tool box. I noticed some corrosion so I doused them in oil and put them back in the box. They still tarnished even when covered in oil. For real corrosion protection of metals the best oil products seem to have other chemicals in them. There are a number of products on the market that work well if you need to protect knives, guns, tools, etc., probably overkill for launch rods unless you are in a really harsh environment. If you're going to use the rods reasonably frequently, they have to be cleaned after use anyway, so probably any oil can work. I don't know what our club uses on launch equipment, when I take the rods out of the pvc tube they aren't corroded and they aren't oily.

 

[WizardOfBoz]

For keeping steel rust free I use Boeshield T9.

 

[Tom Flint]

Again, you do not want to launch any rocket with the motor nozzle in close proximity to a flat plate, as he says, due to Bernoulli lock. My private launch pad has an opening below the rocket that's at least the diameter of the rocket, often moreso. And the blast plate is at a 45° angle, so that the launch gases are ducted out the side... no lock!

View attachment 682948

This is the way. Flame trenches, not legs.

 

[Paul Howard]

As far as coating launch rods and the insides of my launch lugs, I've used the Silicone Oil used in the hydraulics(?) of RC cars and trucks. It's something to use sparingly and keep double-bagged potentially or it get on everything, thus I keep my 2 piece Estes rods in bag when not in use (in storage and in my bike-transport system). It makes cleaning engine exhaust from the rod really easy. But then again, I am using those nice shiny plated Estes 2-piece rods 1/8" and 3/16" and will soon be using the aforementioned/questioned 1/4" Estes 2-piece rod since I decided to get one (and I still need to make the rest of the heavier launch pad for it).