Buttons or Conformal Rail Guides

The Rocketry Forum

Help Support The Rocketry Forum:

Okee

Member
Joined
May 5, 2020
Messages
14
Reaction score
2
I have a kit that came with conformal rail guides, but I have extra buttons as well. The Conformal look easier, but the buttons are really no problem either. Is there a reason to go one over the other?
 

Speaknoevil

Well-Known Member
Joined
Mar 18, 2018
Messages
1,144
Reaction score
538
If it is a minimum diameter design (and it is not high-performance enough to justify using my launch tower), then conformal rail guides are what I use, otherwise buttons.
 

Okee

Member
Joined
May 5, 2020
Messages
14
Reaction score
2
Reading between the lines - buttons are slightly more aerodynamic?

This is not high performance and the rails seem easier/more forgiving so I'm leaning that way.
 

manixFan

Not a rocket scientist
Joined
Feb 15, 2009
Messages
2,519
Reaction score
1,690
Location
TX
Conformal guides also have a tendency to pop off it you twist the rocket at all as you are loading it on the rail. I’ve used them and finally settled on JB Weld to keep them in place. Good surface prep is a must, on both the rocket and guides.


Tony
 

Speaknoevil

Well-Known Member
Joined
Mar 18, 2018
Messages
1,144
Reaction score
538
Reading between the lines - buttons are slightly more aerodynamic?
Not quite sure on that. I use a Dremel and cut a single rail guide into two pieces and angle the leading edges so mine are quite a bit smaller than stock.
 

Okee

Member
Joined
May 5, 2020
Messages
14
Reaction score
2
I can get them aligned - but popping off is a whole other level of issue...lol I have extra buttons, so maybe I will standardize on that.
 

TonyL

Lifetime Supporter
Joined
Nov 13, 2018
Messages
259
Reaction score
147
I thought conformal rail guides looked cool [they still do], but after fighting them on almost every single time [even when aligned correctly, the first one on can be quite finicky] and breaking off a couple, I chose to replace them with regular rail buttons rather than put the things back on.
 

dr wogz

Fly caster
Joined
Feb 5, 2009
Messages
8,117
Reaction score
3,689
Location
Land of Poutine!
Buttons. Smaller contact area on the rail.. And, generally made from a more slippery material



and all the stuff the above posters said..
 

Funkworks

Low Earth Orbit, obstructing Earth's view of Venus
Joined
Jul 28, 2018
Messages
3,057
Reaction score
3,031
Depends on the kit and your plans with it.
 

Okee

Member
Joined
May 5, 2020
Messages
14
Reaction score
2
Thanks for all the comments! I've decided that I will put buttons on everything where it is an option.
 

rvanler65

Well-Known Member
Joined
Jun 28, 2011
Messages
68
Reaction score
6
Yeah I have conformal lunch lugs on 1 rocket........not a fan!! Have gone back to rail buttons.
 

Mugs914

Beware of the leopard.
Joined
Oct 1, 2012
Messages
2,021
Reaction score
2,931
Location
Temple TEXAS
I like rail guides myself. I think they look more like an actual rocket part (I'm kinda weird that way :rolleyes: ). I guess they can be a bit finicky to get started on the rail sometimes, but it has never been an issue worth mentioning for me.

I use the Acme aluminum guides and like Speaknoevil said, I cut them in half. I always use JB Weld to stick 'em on the tube. I dremel some fairly major cross-hatch on the back of the guide and strip the tube down to fuzz, or heavily scuff fiberglass. If it is a bigger, heavier or faster rocket I like to drill a couple of holes through the middle of the guide and into the tube so that the JB mashes down in there good and makes a little rivet, just for extra mechanical bond. Never have had one come off yet.

You can see the two little holes (sorta) in this pic.
rail guide.jpg
 

mbeels

Yes balsa
Joined
Feb 9, 2019
Messages
3,002
Reaction score
1,732
I've used both, I usually prefer buttons. There are also the rail guides from Wildman that "look" aerodynamic and have a screw hole.

 

wsume99

Well-Known Member
Joined
Feb 28, 2014
Messages
257
Reaction score
70
I printed my own version of the conformal buttons. Here's a set on my G Force. I doubt they are more aerodynamic than the standard round rail buttons but for me they are definitely cheaper.
 

Attachments

  • 15907840852884444756151521972427.jpg
    15907840852884444756151521972427.jpg
    46.7 KB · Views: 52
Last edited:

AfterBurners

Well-Known Member
Joined
May 8, 2012
Messages
8,022
Reaction score
568
Conformal rail guides are not very forgiving of misalignment... if you use them, it helps to have a piece of rail handy to align them with.
Draw the line and center them that way. That's how I usually do it
 

AfterBurners

Well-Known Member
Joined
May 8, 2012
Messages
8,022
Reaction score
568
I like rail guides myself. I think they look more like an actual rocket part (I'm kinda weird that way :rolleyes: ). I guess they can be a bit finicky to get started on the rail sometimes, but it has never been an issue worth mentioning for me.

I use the Acme aluminum guides and like Speaknoevil said, I cut them in half. I always use JB Weld to stick 'em on the tube. I dremel some fairly major cross-hatch on the back of the guide and strip the tube down to fuzz, or heavily scuff fiberglass. If it is a bigger, heavier or faster rocket I like to drill a couple of holes through the middle of the guide and into the tube so that the JB mashes down in there good and makes a little rivet, just for extra mechanical bond. Never have had one come off yet.

You can see the two little holes (sorta) in this pic.
View attachment 418624
Those look similar to Aerotech guides
 

JackC

Well-Known Member
Joined
May 2, 2020
Messages
284
Reaction score
211
My experience has been to use the Acme conformal guides if your rocket is minimum diameter. If you draw your lines on your airframe to help you center the guides, you should be fine. I've used them on a 5.5 inch Nike Smoke which has worked for years but my new thinking would be to use rail buttons on non-minimum diameter rockets.

I agree to use the Dremel rough sanding wheel to cross-hatch both the rear surface of the rails and the corresponding area on the rocket to create a proper attachment surface. Then I use JB Weld applied to the surface of the rocket and the rear surface of the rails. Once I've done this, they never pop-off.

If you're using an Acme fin can or a Fisher Max-Q fin can, I recommend using the 2.26 extended Acme conformal guides to create enough clearance between the rocket and the fin can. Apply the lower rail slightly above the top of the fin can to assure clearance.
 

DRAGON64

Well-Known Member
Joined
Jan 18, 2009
Messages
4,451
Reaction score
600
Location
Toney, AL
Years ago there was a concern of the conformal rail guides, the aluminum one, were galling the 8020 rails over time. I generally try to stay with buttons of 3D printed conformal guides.
 

grouch

Well-Known Member
Joined
Apr 9, 2011
Messages
3,840
Reaction score
767
Location
Phoenix AZ
You can use a long straight edge placed between the "nubs' of the conformal guides to align them. Glue one on first and center the other one off that once cured.
 

KenECoyote

Well-Known Member
Joined
Mar 19, 2015
Messages
3,148
Reaction score
439
On one of my builds I used both...rail guide in the back and button up front. Seems the best of both worlds (not much fighting to put on the rail) and looked pretty cool imo. If aerodynamics is your thing, I'd think the front button smooths the air for the back rail guide. 😁
 

hball55

Well-Known Member
Joined
Nov 20, 2013
Messages
2,434
Reaction score
579
Location
Oroville, CA
Reading between the lines - buttons are slightly more aerodynamic?

This is not high performance and the rails seem easier/more forgiving so I'm leaning that way.

Just based on Rocksim results, conformal rail guides outperform rail buttons, though the difference isn’t significant enough to really matter.
 

Tractionengines

Well-Known Member
Joined
Aug 29, 2020
Messages
461
Reaction score
351
Location
Northeast Ohio
Here is what I have been using lately. Direct from 80/20. (# 6797 for 1010 rail, and # 6897 for 1515 rail) Low cost raw part. Takes me 20 minutes with hacksaw, sander, and drill press to finish into 1 screw or 2 screw version. Made from UHMW-PE (plastic, very similar to Teflon). So VERY smooth sliding in the rail. (No chance of damage to rails, like Aluminum guides.)
Only issue is you can NOT bond to the UHMW-PE. (Glue or Epoxy) SO SCREWS ARE REQUIRED. I drill out the pilot hole and then countersink for 8-32 flat-head screw.
80-20_linear_bearing_1.jpg 80-20_Linear_Bearing_2.jpg 80-20_Linear_Bearing_3.jpg 80-20_Linear_Bearing_4.jpg
 

cwbullet

Obsessed with Rocketry
Staff member
Administrator
Global Mod
Joined
Jan 24, 2009
Messages
29,751
Reaction score
7,221
Location
Glennville, GA
Just based on Rocksim results, conformal rail guides outperform rail buttons, though the difference isn’t significant enough to really matter.

I am not surprised. I prefer the long connection of the rail guide over the point connection of the rail button. Rail buttons can allow rotation after the top one leaves the rail.
 

cls

Well-Known Member
Joined
Jan 21, 2009
Messages
2,291
Reaction score
40
Never got a good bond on the rail guide (aluminum), they pop off eventually. Screws and delrin, done.
 
Top