27mm tubing

I had some for a long time, but now all that's left is one piece 18" long, with a bit of paint on one end.

Measure it exactly and post the spec. Doug Pratt could probably order it fresh.

Jerry

I'm not familiar with the FSI tubes (at least, I don't think I am :-) But if 27mm is the actual OD, then there are two choices you might consider:

- Totally Tubular

sells a T-1.04 which has an OD of--you guessed it--1.04 inches, or 26.4 mm. This is the Centuri ST-10 clone.

- Estes HBT-1090 has an OD of 1.09 or 27.7 mm. This tube is no longer sold by Estes, though you may find some where fine Estes parts are sold. This tube was used in the Corkscrew, Fire Streak, Hijax, Banshee, and similar kits (look for kits with a diameter of "1.0 inch").

(LOC 1.14 tube is 29mm, Jerry.)

I don't have the old FSI specs here in from of me, but I'm betting there's a tube that's within a few thousandths. It is the Quest 30mm tubing. Even tho the FSI '27mm' tubing was made for their 27mm motors, there was a lot of slop when you installed a motor. I actually made some AeroTech motors fit in a stock FSI tube. The other option is to find some of the NCR by Estes motor mount tubing; as it's also probably close....

chad

Perhaps 29mm coupler tubing would be about the right size. Either TT or BMS might have this.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Apogee thin wall 29mm tubing is very close

1.18OD/1.14 OD vs. 1.17OD/1.13 ID for RT-10.

Zack Lau W1VT NAR 80361

IIRC, FSI kit tubing, at least for a while, was made by Stone. It had an obnoxious rough finish that had to be sanded off. It was strong, but I loathed it.

I happened to remember that because I'm in the process of vetting new sources for tubing for my own kits. I've found some really nice options for the finish layer, and I have to pick one. But I know one thing: they will be thicker and stronger than Estes tubes. I used a length of Estes BT-50 for a prototype kit for the new E motors, and the ejection charge burned through the tube half an inch above the motor mount. There's no excuse for that.

Doug Pratt

It was crap but to properly duplicate it you have to deliver crap.

So you are going to do what USR has done since 1979 and ACE since 1976? Good.

Jerry

Stone for CMR and FSI (IIRC).

I bought one big batch long, long ago (RB74 sized).

The burning of the tube was probably not the ejection charge, but rather the delay afterburn. It's quite a scorcher.

-Fred Shecter NAR 20117

-- ""Remove "zorch" from address (2 places) to reply.

I can concur with this. I recently used a piece of BT-50 as a stuffer tube in a BT-80 based bird that I built, and after 3 flights on just D and E Estes motors, the tube had burned through completely. If I hadn't noticed the damage, there might well have been a ballistic return on the next flight.

I think the solution is to find a sleeve of more durable, flame resistant material that will just fit into BT-50, and glue a 6" long or so piece inside the motor tube just in front of the motor mount.

U.S. Rockets BT-9. Available in a wide variety of lengths.

Jerry

Didn't someone once make a foil lined BT-50 type tube?

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Estes supplier makes them for Estes and errortech. ET used it for a reloadable parts to distinguish sizes.

Jerry

Yes, as Steve pointed out, TT makes the T-50mf, and also has several rings to accomodate its slightly larger girth.

I've used it on lots of stuff. Only problem is that the foil tends to delaminate forward of the motor. Then, when you slide in a longer motor, you end up with a wad of burnt foil ahead of it.

It's not a bad idea. It just needs some refinement. In the interim, I suggest using some other tube with either an ablative coating of CA or yellow glue, or a throwaway insert of rolled up cardstock. BMS has a nice thickwalled BT-50 that I like.

Doug

I think Totally Tubular or LOC still offers that. I got one of the Mega Vega upscale kits from QModeling

and it uses foil lined BT-50 for the motor mount. Super nice kit!

Scott McCrate NAR 71680

One possible candidate is the Nomex paper offered by Totally Tubular. I got several sheets but have yet to try it out. It is like a very tough parchment in texture and is normally manufactured for electrical insulation purposes. One place I've heard it used in a kit was in the

24mm ABS Sprint by Shadow Composites where they use it to line the aft end of the body shroud. Stuff is apparently pretty adverse to accepting most glues, but as I said, I haven't played with it yet.

Scott McCrate NAR 71680

I used it with the 24mm E Streamer Duration models at NARAM. We used E9's and regular Estes tubes for the models. I wrapped a 3.5"x6" piece of the .002 Nomex paper around the forward end of the E9 and taped it to the motor, leaving about 5" of it--curled in a cylinder--ahead of the motor as protection. I was going to recommend this practice when I first read this sub-thread, but I realized I hadn't actually checked to see if it worked. So I pulled out one of the models and immediately felt a soft spot in the tube ahead of the motor (motor was still in the rocket...what can I say, sometimes it takes me awhile to unpack.) I pulled the motor...almost nothing was left of the Nomex paper but a slender cinder, and the tube was badly charred on the inside. I might get one more flight out of the rocket....

The thicker Nomex paper might work. I'll try it at the Steel City Smoke Trails III next month in the E SuperRoc Duration event. I'm also using the thick-walled tubes from BMS (T50-24HW).

Well, my solution is to get my own tube made to better specifications than BT-50. I'll use up what little BT-50 I have left in my Pioneer kit, which uses 18mm motors that aren't going to scorch the inside of the tube. My other kits have used thicker-walled tubing since I introduced them. I guess that's why it was so annoying to pick up the BT-50 rocket and see the paint blistered off by the ejection charge.

Doug Pratt