Argent with an H: do I need rail buttons?

[ActingLikeAKid]

As mentioned in another thread, I'm going for my L1 with my Estes Argent. It has the stock 1/4" lugs on it. Would those be sufficient for an H motor? If I need rail buttons, I have a section of aluminum conformal rail button; I'd just need to get a top button. Since the launch is Sunday, it's too late to order new buttons; options are:
-buy a nut/bolt/washer and scavenge a rail button from another rocket
-bring 5min epoxy to the launch and pre drill the rocket; when I get there, buy a button from the onsite vendor.

Thoughts?

 

[K'Tesh]

Need? No.

However, you might want them anyway. I'd scavenge one off of a rocket you already have.

The problem with launch rods is that when you are dealing with HPR, rod whip can be a real problem for flight performance. Rails are much more stiff. So, you won't have that problem.

 

[mikec]

I wouldn't mix a conformal rail guide with a button if that's what you're suggesting; they probably have different heights and could bind.

The 1/4" lugs will most likely be fine.

 

[ActingLikeAKid]

Hadn't thought about that. I guess I could just mount one onsite... 1min epoxy should be enough, I'd think (iirc the 5min hits full bond in 24h, but the 1min gets there in 30 min).

 

[Banzai88]

I have launched my argent on Gs and Hs plenty of times on a 6 foot 1/4 inch rod. There's some whip, but not bad. Wind dependant, more than anything else. No issues.

 

[AKVP]

Buttons...yes. Rod Whip can be very bad. Some clubs do not allow lugs on small high power. All it takes is one time to have it whip off the rod...and go sideways and you will know what I mean. High power and large mid power always launch better off a rail. Have fun be safe!

 

[TopRamen]

By "Aluminum Conformal Rail Button", do you mean ACME Rail Guide?

If so, cut it in two, and then you have two.

I like to do that and it works just fine, but I also put a couple screws in just to make sure, as I like to overdo most things.

I can do two rockets with one package of guides.




This one has flown 8 times with a split ACME Guide, and does so quite nicely.:



She'll be going up in staged configuration soon.

 

[Crash-n-Burn]

I think the x factor is the field size. Rod whip is a factor that you can account for - if you fly on a large field then a less-than-straight flight might not be a problem. I prefer buttons and rails to minimize trajectory variables due to smallish fields and prevalent trees.

So yeah, consider your field. You should have a some simulation of apogee - if not run the rocket through thrustcurve.org. Then consider where a 15 degree flight angle variance would put your recovery area. Then decide what your own risk threshold is. For what its worth, I spent all day at the last launch saying 'I'm not flying this rocket" until the wind died down a bit. Flew it into a swamp. Fun times.

 

[Kruegon]

Estes Argent, rail buttons, transition a/v bay, I200.

She went to over 3100' with a beautiful recovery. I don't think I would have flown it that fast without rail buttons.

 

[TopRamen]

Anyone got any useful advice for the OP?
It's cut his guide in half or bust.
Would you trust a fast cure Epoxy to cure on your way to the Pad, only to accidentally screw it up while fitting it to the rail????

Who even trusts fast cure Epoxies for anything anyway? Especially without wire gauge Epoxy rivets?

This poor guy is forced to fly with a club, on their schedule.
He has to get it perfect the first go, or his launch window will pass.
He is smart enough to know that a rail is better than a rod, but he only has this one rail compatible thing.
What would YOU do????

Hack, I'de use rail compatible Screws with heat shrink tubing, and a finishing epoxy veneer if I had to, but his single rail guide is plenty long enough to make two out of, if that is what he has.

Sometimes you just work with what you have, and it turns out to be plenty.
The ACME Rail Guides definitely provide "Plenty".

He should consider himself lucky that he does not have an actual single "Rail Button".

Good luck cutting one of those in half and making it usable.

 

[mikec]

What motor are you planning to use?

FWIW, I have several rockets of about this size that I fly regularly with 1/4" rods. Make sure the rod is clean and the lugs don't bind and you will most likely be fine unless you're flying a very high-thrust motor, especially if the launcher base is rigid. Many rod whip problems start with the base moving with the initial thrust.

I expect that cutting the rail guide in half would work OK too.

 

[Steve Shannon]

I would either cut the Acme guide into two shorter guides or go to the local hardware store, buy some nylon washers and spacers and make a couple of buttons.


[emoji1010] Steve Shannon [emoji1010]

 

[Wayco]

I fly my Argent regularly on small H motors, the H115 Dark Matter is one of my favorites. It has 1/4" launch lugs and is flown off a stable HPR pad. Never noticed any rod whip. Choose your motor accordingly, you will have no problems.

 

[JoeG]

Thoughts?

Well, since you asked.

As mentioned in another thread, I'm going for my L1 with my Estes Argent. It has the stock 1/4" lugs on it. Would those be sufficient for an H motor? If I need rail buttons, I have a section of aluminum conformal rail button; I'd just need to get a top button. Since the launch is Sunday, it's too late to order new buttons; options are:
-buy a nut/bolt/washer and scavenge a rail button from another rocket
-bring 5min epoxy to the launch and pre drill the rocket; when I get there, buy a button from the onsite vendor.

I think sometimes people forget there was high power rocketry before rails. Are rails better? Absolutely! Are they mandatory? No. We used to launch some pretty good sized rockets on rods. We had a collection of 1/4", 3/8", 1/2", 3/4" and 1" and flew L and M motors from rods. That being said I would recommend converting the rocket to buttons so you can use a rail. I have done this plenty of times at a launch for myself and others. If there is someone there experienced enough to sign your paperwork then they should be able to help you.

If you decide not to convert then the lugs themselves are not as much of a concern as the pad and rod you have access to. Make sure it is a stable pad with a rod that is long enough to get you to a stable velocity but not too long and that the rod is mounted solidly.

I still have rockets that have 1/2" lugs on them but I use rails on everything now except my upscale Mars Lander and I would use them on it if I could figure out a way.

Good luck on your L1.

 

[ActingLikeAKid]

Thanks, y'all. I went ahead and cut the conformal button (yes, it's an Acme). I'm not sure what epoxy I have in my toolbox right now; I think I have some 5 minute...I think that as long as I scrape off the paint on a good section and rough up the bottom of the buttons, epoxy should be fine - the lugs have been fine with a G motor and they have 5min epoxy with a much smaller surface area. Just need to work out positioning and glue them on. Once the glue is cured, is it overkill to put a little lubricant on the buttons? Anything anyone recommends? I was thinking something dry and un-residue-y, maybe graphite?

 

[Steve Shannon]

Not a bad thing to do, but not necessary. Frequently at club launches someone will spray lube the rails every so often.


[emoji1010] Steve Shannon [emoji1010]

 

[Barkley]

Thanks, y'all. I went ahead and cut the conformal button (yes, it's an Acme). I'm not sure what epoxy I have in my toolbox right now; I think I have some 5 minute...I think that as long as I scrape off the paint on a good section and rough up the bottom of the buttons, epoxy should be fine - the lugs have been fine with a G motor and they have 5min epoxy with a much smaller surface area. Just need to work out positioning and glue them on. Once the glue is cured, is it overkill to put a little lubricant on the buttons? Anything anyone recommends? I was thinking something dry and un-residue-y, maybe graphite?
View attachment 290877

Make sure you scuff the bottom of the conformal rail guide HEAVILY. The epoxy needs the it.

 

[TopRamen]

Make sure you scuff the bottom of the conformal rail guide HEAVILY. The epoxy needs the it.

That, and you don't need to add screws, but drilling a couple of holes would do well enough to make epoxy rivets.

 

[Steve Shannon]

That, and you don't need to add screws, but drilling a couple of holes would do well enough to make epoxy rivets.

Drilling the aluminum for epoxy rivets would not result in increased strength because aluminum is much stronger than epoxy. Perforations in the paper tube might help, but I'm not certain.

 

[K'Tesh]

Drilling the aluminum for epoxy rivets would not result in increased strength because aluminum is much stronger than epoxy. Perforations in the paper tube might help, but I'm not certain.

It's not the strength of the aluminum here that is the concern. It's the strength of the epoxy/aluminum bond. If the epoxy doesn't have enough of a surface to grip to, that would be where your failure point is. Holes in the aluminum would create rivets that ensure that the bond is more than just surface deep.

 

[Banzai88]

Epoxy rivets also help with surface mounted fins, like the upper fins of an Optima or a Binder Terrordactyl.

 

[Steve Shannon]

It's not the strength of the aluminum here that is the concern. It's the strength of the epoxy/aluminum bond. If the epoxy doesn't have enough of a surface to grip to, that would be where your failure point is. Holes in the aluminum would create rivets that ensure that the bond is more than just surface deep.

Roughening up the surface increases the surface area, which will result in greater strength for the epoxy/aluminum transition. Drilling a bunch of dimples could do that also, but drilling a parallel wall hole leaves the cross sectional area the same as the epoxy/aluminum interface would have had.
It's immaterial anyway. The epoxy/aluminum interface is orders of magnitude stronger than the epoxy/paper interface.

 

[TopRamen]

To be fair to everyone here with their opinions of how now, the ACME Guides used to come with a double sided clear tape, and they recommended that as the mounting method.:y:
They even thought CA would be suitable.
I use JB Weld, tiny screws and roughed up mating surfaces.
The body tube gets the epoxy rivets.

 

[Steve Shannon]

To be fair to everyone here with their opinions of how now, the ACME Guides used to come with a double sided clear tape, and they recommended that as the mounting method.:y:
They even though CA would be suitable.
I use JB Weld, tiny screws and roughed up mating surfaces.
The body tube gets the epoxy rivets.

View attachment 290903

The first one I saw was NSL 2001 in Utah. I was working as a pad manager and watching a guy put his rocket on a rail. The problem with the Acme rail guides was quickly revealed. The design doesn't allow much movement of the upper end of the rocket once the bottom end has been placed on the rail. He twisted the entire lower rail guide off his rocket while trying to align the upper guide.

 

[TopRamen]

The first one I saw was NSL 2000 in Utah. I was working as a pad manager and watching a guy put his rocket on a rail. The problem with the Acme rail guides was quickly revealed. The design doesn't allow much movement of the upper end of the rocket once the bottom end has been placed on the rail. He twisted the entire lower rail guide off his rocket while trying to align the upper guide.

Which is why I suggest the screws and overdoing it.
It takes like ten minutes to do it right the first time, but this guy is going for his L1, so if he whiffs at the pad, he'll have to wait til' the next time his club has whatever it is that clubs do.

 

[Cabernut]

This is a good example of how many of us less experienced folks can learn a LOT from others who have been-there-done-that-once-and-never-again-here-ill-save-you-the-trouble

 

[Steve Shannon]

Which is why I suggest the screws and overdoing it.
It takes like ten minutes to do it right the first time, but this guy is going for his L1, so if he whiffs at the pad, he'll have to wait til' the next time his club has whatever it is that clubs do.

I agree with the screws.

 

[Zebedee]

I can confirm that conformal aluminum rail guides + a 3in MD fiberglass body roughed up by 80 grit sandpaper then cleaned with acetone + JB Weld + a CTI M2020 motor results in some smooth grey JB Weld patches left on the rocket.
Lift-off was fine but the rail guides were never seen again.

I suspect that any epoxy + conformal guides (even when sawed in half) on the Argent tube will be fine for G/H/I motors.

I also think that 1/4 lugs would be fine for a single G/H flight but I would put rail guides on it for the next flight and I'd suggest these: https://www.scpconcepts.com/rocket-accesories.html

 

[ActingLikeAKid]

OK!!!
So I tried to follow the guidance here. Drilled a couple of holes in the BT and one each in the halved guide. Roughed up everything with 150 grit (it's what I had) and then scored the aluminum with a drill bit (that actually worked SUPER well - got a nice crosshatch of roughness).
Then inspiration hit and I used a porta-pad launch rod to align the guides, both with each other and with the rocket. It's sitting out right now baking in the warm NC afternoon sun. JB weld was applied at ~9am today, launch is at 11am tomorrow, so I think I'm in good shape. Also resting the rocket betweeen two trash bins proved to be perfect support.

 

[Cabernut]

Looks like you're all set. Good luck tomorrow!