BT-56 Centuri Groove Tube

[Fishhead]

Looking for a potential project to use up all of the BT-56 you have laying around? I was, and this is the result. It will someday fly on the "mighty" Estes E, but unfortunately not any time in the next two weeks. I still need to find some thin foil tape for brightwork, but other than that it's ready to rip.

 

[Fishhead]

My apologies for the bad editing job, but I'm just glad to be back posting pics again. This is the second view.

 

[centuriguy]

Actually, the "creative cropping" on the second photo show how well it would fit nicely into an oval matted-frame for display on your desktop.

 

[Fishhead]

I have NO idea how I did that. I hit a button and the picture fit the TRF parameters, so I used it.

 

[laseradam]

I used aluminum metal "duct tape" for the metal highlights on my Taurus clone. It might work good for your needs. I saw small rolls at Big Lots for about a dollar.

 

[centuriguy]

Originally posted by Fishhead
I have NO idea how I did that. I hit a button and the picture fit the TRF parameters, so I used it.

Happy accidents. They're too much fun.

 

[centuriguy]

Originally posted by centuriguy
Happy accidents. They're too much fun.

As opposed to Scram-Jet nose cone separations.

 

[rokitflite]

Hey Fishhead,
Looks great! I made a Groove Tube II a little ways back. It's based on a BT-60 and its not scaled to the original one. I named it groove tube II because I could not think of anything else! I built it to test some Krylon paint to see if it was similar to the color of the Delta rocket. It flies great and has about a dozen launches on Cs and Ds under its belt. Good luck with yours!!!

 

[ronhill]

I've been wanting to start a thread on tube fin rockets so I hope you don't mind if I horn in on your Groove Tube discussion. The attached photo is my BT-60 based tube fin design that flew many times on the D12-7 this year. Even though tube fin rockets have a lot of drag, it sure flew high.

Ron

 

[ronhill]

The single stage version flew so well, I opted to stage the "Tube." The first stage was essentially the same design--six BT-60 fins around a BT-60 core. The bottom stage had a D12-0 and the upper stage again had a D12-7. It flew great the first time. The stunningly bright blue sky was the only reason I could see it at apogee.

 

[ronhill]

The second flight of the two-staged Tube, for whatever reason, wasn't successful. The two-stage stack went horizontal about 75 feet above the ground. The second stage dutifully ignited in this horizontal position, it flew cross country, and it hit the ground during the delay charge burn. Something must have shifted aft because the first flight was stable, but the second flight wasn't.

I couldn't find the corpse of the rocket that day.

Six weeks and several rain storms later, a member of the club found the dead rocket. The main body tube was in bad shape because of the impact and rain, but the tube fins (probably because they were coated inside and out with multiple layers of paint) were in good shape.

I pulled off the old tube fins, attached them to a new central tube, used the same old nose cone and nylon parachute, and repainted it. The "Tube II" has flown 3 times since it was revived. No more multistaged tube rocket for a while.

 

[Fishhead]

Originally posted by laseradam
I used aluminum metal "duct tape" for the metal highlights on my Taurus clone. It might work good for your needs. I saw small rolls at Big Lots for about a dollar.

I have some Bare Metal Foil left over from my car modeling days. I'm going to give that a try first, just because it's on hand. This will be my backup plan.

 

[Fishhead]

Any of you find the need to add nose weight to your upscales?

 

[rokitflite]

Hi Fishhead,
Nope, no nose weight here. 23" BT-60, 5" tube fins, D motor mount and a Mean machine nose cone. Perfectly stable.

 

[Fishhead]

Good deal. I'm hoping to fly mine sometime this weekend. I'd hate to have another flight like that of my Vector V.

 

[teflonrocketry1]

I still have my original Centuri Groove Tube, it must be over 25 years old and I still fly it! It inspired all those articles I wrote on tube fin simulations.

Bruce S. Levison, NAR #69055

 

[stevecarr]

How much do you need I will give you some? (tape)
Ive seen Rons rocket fly too.
Maybe you can aim them at each other saturday.

 

[Fishhead]

Originally posted by ronhill
The single stage version flew so well, I opted to stage the "Tube." The first stage was essentially the same design--six BT-60 fins around a BT-60 core. The bottom stage had a D12-0 and the upper stage again had a D12-7. It flew great the first time. The stunningly bright blue sky was the only reason I could see it at apogee.

Man, I'm slipping! I can't believe that I looked at your pictures the other night without realizing that they were taken on the Quark pad at the VOA. That huge mound o' dirt in the background should have been a dead giveaway.

 

[Fishhead]

Originally posted by stevecarr
How much do you need I will give you some? (tape)
Ive seen Rons rocket fly too.
Maybe you can aim them at each other saturday.

It's looking less and less like I'll make it on Saturday. Tomorrow will be the acid test based on what I get done. (Geez, all I need is a couple of hours.)

 

[ronhill]

Originally posted by Fishhead
Man, I'm slipping! I can't believe that I looked at your pictures the other night without realizing that they were taken on the Quark pad at the VOA. That huge mound o' dirt in the background should have been a dead giveaway.

It sure is VOA. I still can't believe I didn't know it was being used as a flying field for a couple of years before I joined. It's a great field. Hope to see your "tubes" flying out there someday. Looks like Saturday is a wash (literally). Sunday should be better.

Ron

 

[ronhill]

Bill

Great meeting a fellow tube rocket fan today. Did you fly the Groove Tube II a third time? I had to leave before you returned from fetching flight number 2. I'd guess a bit more nose weight would ensure a completely stable flight.

I mentioned my efforts with a rack rocket. Here's one (pic attached) I launched several times earlier this year. As you see, the booster stage used the CHAD approach--not fins, just drop away. This one really got up to altitude on a D12-0/D12-7 combination. The flights were beautiful. I lost it in August simply because I lost sight of the streamer on a cloudy day. Mark returned it today but the mower had eaten it first. I will rebuild based on C engines rather than D engines to keep the altitude at a reasonable level. Maybe it will be a three stage version this time.

Ron

 

[Fishhead]

Originally posted by ronhill
Bill

Great meeting a fellow tube rocket fan today. Did you fly the Groove Tube II a third time? I had to leave before you returned from fetching flight number 2. I'd guess a bit more nose weight would ensure a completely stable flight.

I mentioned my efforts with a rack rocket. Here's one (pic attached) I launched several times earlier this year. As you see, the booster stage used the CHAD approach--not fins, just drop away. This one really got up to altitude on a D12-0/D12-7 combination. The flights were beautiful. I lost it in August simply because I lost sight of the streamer on a cloudy day. Mark returned it today but the mower had eaten it first. I will rebuild based on C engines rather than D engines to keep the altitude at a reasonable level. Maybe it will be a three stage version this time.

Ron

Never found it. I walked around for an hour stomping through the brush, then went back for another hour after I got pissed off and quit flying. Not my weekend, I guess. Based on how close it looked like it landed to the road, I think someone might have picked it up as a keepsake on their way out of the VOA.

 

[ronhill]

Originally posted by Fishhead
Never found it. I walked around for an hour stomping through the brush, then went back for another hour after I got pissed off and quit flying. Not my weekend, I guess. Based on how close it looked like it landed to the road, I think someone might have picked it up as a keepsake on their way out of the VOA.

Oh, no! Didn't realize you lost it. It sure was a beauty. Your theory on someone picking it up may be valid. I had to chase down some soccer kids (at least I can still run faster than 9 year old kids) to recapture one of mine a few months ago.

Hope you opt to rebuild. With a litte more nose weight, it will fly well.

I've lost 2 out there. Both eventually came back in various stages of disrepair.

 

[Fishhead]

As far as I could tell, it cleared the soccer kids, but I saw them chase another one down while I was looking for mine. Right now I'm feeling more than a little bummed. I might try the rebuild with a BT-55. The one I lost took up all of my spare BT-56 and that was my last cone.

 

[rokitflite]

Ronhill,
That Rack Rocket looks real cool! Do you have any other close up pictures of it? Sorry about your Groove Tube Fishhead.

 

[ronhill]

Originally posted by rokitflite
Ronhill,
That Rack Rocket looks real cool! Do you have any other close up pictures of it? Sorry about your Groove Tube Fishhead.

It was one of my favorites this year. Here's a pic that's a bit closer but not much. This happens to be in a single stage configuration on it's first flight just for testing. As I mentioned, it flew beautifully--staged smoothly and occurring at a surprising high altitude for a D12-0.

There is a difference between this and the earlier pic I posted. I originally used aluminun tape to protect the fin booms and the top of the fins. I found that I didn't need the tape on the fin tops so I removed it. The tape on the inside of the booms remained, and they did toast, but the wood was protected. All I had to do was apply another layer of tape.

The fins are 1/16 inch plywood. The booms are hardwood. Otherwise, it's standard construction.

I got this idea from a posting on the web, and tonight when I have more time, I'll try to post a reference.

 

[rokitflite]

Thanks!
Gorgeous finish by the way!!!

 

[ronhill]

Originally posted by rokitflite
Thanks!
Gorgeous finish by the way!!!

Scott

Thanks for the comment. I'm getting pumped up to rebuild. Just wish the lawn mower had not chewed up this one. No more rack rocket launches on cloudy days.

The idea came from a 2002 TRA paper entitled, The Rack Rocket Concept, a Quest for High Altitude , by Ken Good. You can get it from his page at:

members.tripod.com/Tripoli_Rocketry_PGH/kjgboard.html

Ron

 

[rokitflite]

Hey Ron',
That was some interesting reading! I am now considering building one to launch some of my video camera rockets. Have you considered using carbon fiber rods for the rack?

 

[ronhill]

Originally posted by rokitflite
Hey Ron',
That was some interesting reading! I am now considering building one to launch some of my video camera rockets. Have you considered using carbon fiber rods for the rack?

Scott

That would be a great platform for a video camera. You won't believe how smooth the staging is--no tip off at all.

I haven't thought of carbon rods. Can you get square carbon rods? The attachment to the fins and body tube is critical. The wooden square rods are pretty light.

Since you're interested in rack rockets, here's a pic of Rack One. I designed and built this before seeing the rack rocket file you just read. It was just for fun. It flew many times with two stages--Estes D engines.

This pictured flight had 100% Flight Systems Inc. engines. They went out of business long ago. I believe the first stage had 1 C6-0 and two D20-0 engines. The first stage engines were glued and taped together. The upper stage was a E5-6.

The first stage had flashbulb ignition. The E5-6 was woefully underpowered and the rocket was draggy with the large fins. Even with that big boost, the E5-6 went horizontal during its long 5-second propellant burn. Before the delay finished, it hit the ground. But it did have many good flights.

Ron