PNC55 vs. PNC 56

[maricopasem]

What is the diameter difference of the PNC 55 and the PNC 56? Or is there none?

[CPMcGraw]

What is the diameter difference of the PNC 55 and the PNC 56? Or is there none?

Marico,

Enough to matter, but less than you might think...:eek:

Anything -55 is the Estes Cherokee-D and Black Brant sized components, while -56 is the Estes equivalent to the Centuri ST-13 components.

According to the 741 Parts Guide, BT-55 is 1.283" ID and 1.325" OD, with a wall thickness of 0.021".

The SEMROC / Centuri ST-13 is 1.300" ID and 1.340" OD, with a wall thickness of 0.020".

[sandman]

What is the diameter difference of the PNC 55 and the PNC 56? Or is there none?

Yes, there IS a difference.

BT-55 = 1.325" O.D. 1.283" I.D.

BT-56 = 1.340" O.D. 1.304" I.d.

And the Semroc SLS 125 series tube is almost the same O.D. as the BT-56 at 1.340" O.D. but it is thicker walled and 1.25" I.D.

I keep this chart on my desktop.

[maricopasem]

Thank you. I was at the local hobby store yesterday and they had -56 cones and -55 tubes. I ended up just buying -50 tubes and cones. Maybe I'll go back and get the others also and just take to the bigger NC's with some sandpaper.

[CPMcGraw]

Thank you. I was at the local hobby store yesterday and they had -56 cones and -55 tubes. I ended up just buying -50 tubes and cones. Maybe I'll go back and get the others also and just take to the bigger NC's with some sandpaper.

Just order ST-13 tubing from SEMROC. No sanding needed to fit those cones into them.

Here's a heads-up, in case you didn't already know...

The Astrocam 110, aka Snapshot, is a BT-56 / ST-13 nose cone. You could use Carl's tubes to build a much better booster for that camera.

[snaquin]

Thank you. I was at the local hobby store yesterday and they had -56 cones and -55 tubes. I ended up just buying -50 tubes and cones. Maybe I'll go back and get the others also and just take to the bigger NC's with some sandpaper.

Another option you may consider is check the local hobby store and see if they have couplers for the BT-55 tubing and use the couplers to adapt the PNC-56 nose cones onto the BT-55 tubing after you remove the PNC-56 shoulders with a few passes of a sharp knife or razor saw.

I've used this method many times before. It's not a new idea, Al with AAA used to ship kits with PNC-56 nose cones "reworked" as they called it back in the 80's for the thicker walled smaller ID tubing Sandman and Craig made reference to.

I have pictures of an example I did in another thread here:

http://forums.rocketshoppe.com/showpost.php?p=8012&postcount=34

Cut the shoulder off, glue the coupler inside the nose cone and attach the shock cord to the ID of the coupler. I have several packs of the Estes PNC-56 nose cones on hand and I like to adapt them to the Semroc LT-125 series tubing for the added strength and durability and applications where the Estes tubing would not survive flights with higher impulse motors.

:)

.

[Ltvscout]

I keep this chart on my desktop.
Heh, that's the one from Jim Fackert that I have online here:

http://www.rocketshoppe.com/info/BodyTubeRatios.pdf

It's on the Building Tips page of Ye Olde Rocket Shoppe. ;)

[sandman]

Heh, that's the one from Jim Fackert that I have online here:

http://www.rocketshoppe.com/info/BodyTubeRatios.pdf

It's on the Building Tips page of Ye Olde Rocket Shoppe. ;)

Well...DUH!!! :rolleyes:

[Bob Thomas]

The last purchase of plastic cones I bought the difference was only in the ridges. The pnc 56 cones were really 55 diameter with ridges to accomodate the 56 tubing. So sanding them down to remove the ribbing gives you a 55 nose cone. There were some shoulder diameter concerns that were easily sanded out. Similarly, a strip of tape adjusts a 55 cone to 56 tube to a or ST-13 tube. Fill & Finish does the shoulder difference if any is needed. Using Balsa, just order from Carl @ Semroc. His dimensions are precise. The ST-13 is my favorite design tube, along with the 16. Lots can be done for upscaling your favorites.

[A Fish Named Wallyum]

Just off the top of my head, the BT-56 cones can be used to build two of the Centuri Super Kits, the UFO Invader and SSV Scorpion. I believe the nose cone was also used in the Estes Challenger II. I also believe Red Arrow Hobbies still sells BT-56 tubing by the 3-pack. I did an ill-fated upscale of the Centuri Groove Tube using BT-56 tubes and a nose cone. Pick them up. You'll find a use for them. :cool: