Fly Away Rail Guide Questions

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I just bought a 38mm Flyaway rail guides from AMW-Pro to use with my RW Formula 38 and RW Mouse 38 rockets. I ordered the one for standard fiberglass as that is what I believed the Formula and Mouse are made of plus the folks at AMW said I could just add a rubber band to adjust for the smaller sized thin walled fiberglass tubes. When I test fit the guide to the tube it does not seem to grab hold of the tube but slides loosely up and down. It seems this would put the bulk of the pressure being applied to the fins when launched. Is this the way they are suppose to work or should it be a tighter fit so that the pressure of the launch is transferred to the body tube? I was thinking of adding a little bit of foam or tape to the inside of the guide to make the fit a bit more snug. Is this acceptable or did I get the wrong size for my particular rockets?

Thanks - Jim V.
 
It should not slide up and down. Are you sure you don't have thin wall kits? If you have a caliper, take an outside diameter measurement.

Bill Cook (wfcook) is the inventor/distributor of these, so you may want to contact him directly.
 
I believe all of the (newer, at least) RW kits are thin-wall FG. My Go Devil 38 definitely is. In fact the thin-wall fly-away guide is still a loose fit on my Go Devil 38, I still had to shim it to make it a good fit.

On the shimming, I would definitely have to side with rubber bands. The first time I used some carefully-cut pieces of duct tape for the shims, and that worked well (and is certainly more fine-tunable than rubber bands) the first event (two flights), but I can only guess that while sitting a month (mid-September to mid-October) for the next event the tape must have shifted a bit and left some tacky surfaces, my next flight the guide didn't come off until apogee, which both resulted in a much lower flight than expected (that was my first attempt at breaking a mile and it wasn't even close) but also resulted in the loss of the guide (never found it on the field, don't even really know just where it would have come down). I will note that Bill replaced it free of charge which was totally unexpected. Now I'm using rubber bands, all I had the first time was the supplied bands and they still weren't quite thick enough for my Go Devil and the thin-wall guide, so I put some blue tape between the guide and the rubber band, at least this is spaced away from the airframe so it shouldn't have a chance to stick. I still need to buy an assortment of bands to have more choices on thickness (and not be chewing through the supplied bands which are perfect for the guide release).

I shoot to have it a fit snug enough that you can grab the rocket somewhere other than the guide, move the rocket up/down on the rail and have the guide stay in place on the rocket. This was tricky my first event, what seemed right off the rail didn't slide on the rail at the pad, I believe it was due to the screw heads grinding against the inside "V" of the 1010 rail (all of my other rockets use countersunk screws so this wouldn't be a problem with them, the pan heads on these guides seem very large to me. But I wound up removing a strip of tape at each end which was just about at the tipping point between rail-to-guide friction and guide-to-rocket friction. But it flew well every time, I'm on my 5th flight with these guides (this past Saturday I finally did my mile shot successfully) and there's not so much as a mark on my fin fillets / etc.
 
I sent a PM to Bill posing the question but have yet to hear back which is why I thought I'd post here for some ideas. I checked the RW website and they don't mention the Formula and Mouse 38 being thin-walled but I suppose it is possible. I did put a couple of the supplied rubber bands on the guides but it was still pretty loose. I was thinking of using a couple small pieces of thin weather stripping (sticky on one side and felt on the other). I guess I'll check the OD tonight when I get home.
 
How are you placing the bands?

I run mine vertically on one or both sides of clamshell depending on needed fit.

DSCN3825.jpg

These are standard guides equipped for use with thin wall tube.
 
I've done the same for mine as Jim suggested. Try adding another band to one side and see if that helps.

Well I measured my RW Formula 38 and the OD is 40.75mm

I tried 4 rubber bands and it still slips easily up and down the BT

38 mm Fly Away Rail Guide.jpg

Guess I'm going to have to find something a little thicker than the bands supplied.
 
Just a comment, the way you have the bands placed you're only reducing the diameter by the thickness of one band. I did that with the thin-wall guide and it was still barely enough for my RW 38mm, so I'm not surprised that it wouldn't be enough starting with the non-TW version. I'd suggest stacking a pair of bands on top of each other on each half (so still 4 bands but it would look like 2 thicker bands), placed opposite each other when you have the guide closed, that might work better. Or use thicker rubber bands.
 
Jim, my apologies for the late response, I haven't been on in a while (life got in the way).

The guides do fit a little more loosely than they used to. I generally double up the rubber band shims if they are loose. In general, being a little loose isn't an issue unless the rocket isn't actually being held straight. The guide should be backed up all the way to the fins and the fins are what pushes the guide up the rail (this also eliminates hard fin strikes).

The advantage to the rubber band shims is that they really grip the heck out of the rocket, preventing slip, and they also help ensure that the guide separation doesn't scratch any nice paint job you may have.

If, however, you find that you just aren't comfortable with the amount of slippage, let me know and I'll send you a thin-wall set. I would never want anybody out at the pad with any of my products unless they were completely comfortable with them from a safety perspective.

Bill _/)_
 
Thanks Bill and Will. I'll try stacking the bands when I get home this evening and see if that provides a better hold. I'm going to pick up some different, thicker, rubber bands on my next trip to Walmart so I can keep the provided bands for their intended purpose.

Thanks again.
 
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