- This topic has 31 replies, 13 voices, and was last updated 17 years, 7 months ago by
Warren B. Musselman.
Warren B. Musselman.-
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Warren B. Musselman
Mike, absolutely fantastic post. Thank you much. Very thorough and I’m interested in the buttons you’ve come up with. My original thought was to machine the buttons out of teflon, but bad experiences with overtightened Delrin buttons binding up in rails made me decide for the stainless. As John mentioned in an earlier post, we’ve been flying metal buttons on our rails for years. The damage we get is largely the result of cleaning with wire brushes and handling damage.
Launch rails and rods are essentially a long-term consumable for the club – in fact the recent addition of 4 new rails (2 x 1515 and 2 x 1010) was done because our older rails were getting rather munged up. Some of those rails go back well into the 1990’s. The main cause of this would probably be the heavy scrubbing in the slots with wire brushes to clean off to gunk that accumulates. That said, as John indicated in an earlier post, we’ve flown metal buttons on our rails since before NCR existed. The stainless buttons I’ve made are very finely machined and tooling marks are basically undetectable without a microscope.
When I fly my L3 at MHM, I’ll break out one of the brand new unused rails and we can do a pre-flight examination and post flight to determine what wear if any occurs. Given that most of the 1515 rails see fewer than 20 flights a year, I think we can assume that we’re not going to produce noticable damage for quite a while if we change our cleaning methods.
Finally, thanks for the correction on the screw head angle – I knew wood screws were 90 degree and I’ve purchased 110 degree machine screws before, but didn’t realize that standard machine screws are 82 degrees.
Final note – it would seem that at least for rocketry, there would be a market for fully hard anodized rails. I’m going to call the anodizing shop my company uses to see how much they would charge to do an 8′ section of 1010 and 1515.
Warren
slipstick
There are some benifits for owning your own launch rails (and pad) to insure you have a slippery launch and to give yourself more prep time w/o slowing down others wanting to get on. When I start more complex rockets I may pop for my own launcher.
I forgot to bring up the coefficient of friction between various materials on aluminum. What we are discussing, in essence, are linear bearings on aluminum rails.
All of these Coefficients of friction are dry interfaces on aluminum.
Aluminum – Static 1.05-1.35, Sliding 1.4
Steel – Static .67 Slidng .47
Carbon fiber epoxy – Sliding .23 to .68 (gets worse over time)
Self-lubricating Plastic on T-Slot – Static .1.8-2.2 Sliding .16
Self-lubricating Plastic on polished metal – Static .16 Sliding .13Its apparent that self-lubricating plastic buttons are the best for initial launch performance. Now if you can get them to fall off right away to reduce drag….
Warren B. Musselman
I’m thinking about maybe multi-piece stainless rail buttons with a teflon washer on both the inner and outer bearing surface.
In general though, I spray WD40 on rails before every flight. It definitely slicks things up.
W
Conway Stevens
Only one problem with spraying wd40 on all the rails. its a penatrant as well as a cleaner. Its job is NOT to slick things up. This is a side effect of the materials that are in Wd40. After you spray it it does not stay slick for long and if there is excess dirt and grunge on the rail the next person that uses it will most likely not have a very slick surface. I highly recommend that a actual release or lube agent be used and avoid such materials as Wd40 and the likes except when cleaning.
Warren B. Musselman
There is a teflon spray I’ve used in the past that would likely be far better. I just mentioned WD40 because I’ve seen a lot of folks in the club use it that way and for that purpose and its usually sitting around.
W
slipstick
I just mentioned WD40 because I’ve seen a lot of folks in the club use it that way and for that purpose and its usually sitting around.
This is actually a very helpful topic, but provides another reason why investing in one’s own launch rail might be a good idea if one is looking for optimal performance.
Its interesting to note that WD40 (Water Displacement 40 – It took 40 tries for the inventor, Norm Larson, to get the right chemical formulation) had its roots in 1953 as the Rocket Chemical Company and was 1st used to prevent corrosion on the Atlas Missile. “Rocket WD40” was put on the store shelves in 1958 and became so popular that the company changed its corporate name to WD40 in 1969.
Love the stuff, used it all over the screws in our F4’s on the USS Coral Sea during Vietnamm 1967-1968, but hate it when used outside as it is a major attractant of dirt. The carrier had plenty, but the prairie has more.
Once sprayed on a rail, the inside of the T-slot, the surface that slides on the buttons, will be permantantly coated with abrasive grunge as it is not accessible by a rag to wipe off. My reccomendation is to only use an evaporitive solvent like Denatured Alcohal, as it will wash away WD40 and other sticky messes. A small bottle brush with non-metallic fibers could be used to clean the inside of the T-slot. Metal wire brushes should be banned from ever touching the rails as they will break through the thin layer of anodizing.
We can do an experiment: take various sprays like WD40, silicone dry lube and others and spray a small spot on our cars, then drive it around. It won’t take long before before the spot will blacken. The best rail is a dry clean rail to eliminate stiction and abrasion.
My favorite use of WD40 is to remove the gummy adhesive from sticky-back labels.
Warren B. Musselman
This is completely off topic, but given the industry you work in Mike, I wonder if you could comment on this.
A while back, it was reported that ALL the hard disk drives in the ISS essentially seized up within hours of one another and have since been replaced with solid state “hard drives” meaning flash or similar Ram disks. Is this an issue with lubricants or bearings in zero-gee? The drives were all about 6 months old as far as in-flight use was concerned.
Warren
Bruce R. Schaefer
I just mentioned WD40 because I’ve seen a lot of folks in the club use it that way and for that purpose and its usually sitting around.
W
And, that’s what we use at every bi-yearly cleaning party. This really IS a good thread, guys. Warren, 10-24/32 screws are fine to hold rail buttons on. I just said what I said earlier since most people use 1/4-20’s. As JW mentioned, probably just over-building. This is really good information you are all providing.
Adrian
I’ve also been happy with some black powder cleaner I picked up at the store where I got my Pyrodex. I think it’s water soluble, but it made cleaning out the inside of my rocket a snap. I wonder if it would work as well on AP residue?
Jeffrey Joe Hinton
For what its worth, BOY SCOUT water works pretty well at cleaning up the AP residue on rails and in motor cases but you need to re-grease afterwards, or use the stuff we used in the Colorado Army National Guard – CLP (Cleans, Lubes, Protects).
Warren B. Musselman
slipstick
Conway Stevens
Bruce R. Schaefer
Adrian
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