PDA

View Full Version : Centuri Eagle Power Outfit


tbzep
06-16-2006, 03:28 PM
This post really belonds to bothf kit collecting and project forums, so I chose projects because the Screamin Eagle needs some work done to it.

I've been wanting one of these for decades. I paid too much for it, but I've let too many of them slip through my fingers over the years and this set was complete except for the original motors. The guy did include an Estes blister pack with a Centuri A8-5 and a couple of Estes C6-5 motors, though....but I wouldn't trust them in any rocket.

Now to the nitty gritty. Whoever assembled the rocket, made a mistake. The tube coupler was not pushed up into the rocket so that the body tube would slip over the fin can. The only thing that held the rocket together when it was flown, was the "thrust tube", which was glued inside the motor mount tube. Evidently the glue didn't withstand the heat of very many launches and came loose. I'm guessing the kid packed everything back in the box nice and neat and forgot about it because everything is in excellent condition. Even the microclips are original and in great shape. There's some rust on the blast deflector, but I'll get over it. ;)

Here's the question. What is the safest way to fix my new rocket? Do I peel everything out from the body tube? Do I take a Dremel and try to eat away some of the tube coupler from inside the body tube? Inquiring minds want to know!

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri1.jpg

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri2.jpg

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri3.jpg

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri4.jpg

A Fish Named Wallyum
06-16-2006, 03:36 PM
Nice, especially when compared to mine. I'll see if I can post some pics later tonight. There's no hope for my Eagle, and no power since 2001. :(

tbzep
06-16-2006, 04:04 PM
Nice, especially when compared to mine. I'll see if I can post some pics later tonight. There's no hope for my Eagle, and no power since 2001. :(

Speaking of no power... I'd love to get my hands on an old red and white Everedy 731 lantern battery for display purposes.

CPMcGraw
06-16-2006, 06:07 PM
...Whoever assembled the rocket, made a mistake. The tube coupler was not pushed up into the rocket so that the body tube would slip over the fin can. The only thing that held the rocket together when it was flown, was the "thrust tube", which was glued inside the motor mount tube. Evidently the glue didn't withstand the heat of very many launches and came loose...

Here's the question. What is the safest way to fix my new rocket? Do I peel everything out from the body tube? Do I take a Dremel and try to eat away some of the tube coupler from inside the body tube? Inquiring minds want to know!

Simple fix, from what the photos show. Start by cutting a small piece of body tube of the same diameter, and glue it over the top edge (shoulder) of the fin can. Use a smear of epoxy for this...

Next, epoxy the assembled forward section into the fin can, using the epoxy to create a gas seal as well as to hold the sections together. You should also use this opportunity to attach a Kevlar thread around that coupler and through a (new) hole in that coupler. After the epoxy cures, then use a filler compound to smooth out any remaining gaps...

This should resolve any issues that plagued the previous owner...

tbzep
06-16-2006, 07:03 PM
That's exactly what I was thinking about doing. However, as I fooled with the "thrust coupler" (greeinish black tube coupler) it felt a little loose. I was able to work it out of the larger tube coupler which let me get at the bigger tube coupler with the dremel tool. I was able to remove about 1/4" from it. I scuffed up the smaller tube coupler to let the glue soak into it a little better.

I don't have any kevlar line. However, I only plan to fly this bird a few times off the Powr Pad for some photos and the whole thing will go up on the shelf for display. Maybe I'll find another one in the future and use one of the sets for active flight duty.

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri5.jpg

CPMcGraw
06-16-2006, 07:57 PM
That's exactly what I was thinking about doing. However, as I fooled with the "thrust coupler" (greeinish black tube coupler) it felt a little loose. I was able to work it out of the larger tube coupler which let me get at the bigger tube coupler with the dremel tool. I was able to remove about 1/4" from it. I scuffed up the smaller tube coupler to let the glue soak into it a little better.

I don't have any kevlar line. However, I only plan to fly this bird a few times off the Powr Pad for some photos and the whole thing will go up on the shelf for display. Maybe I'll find another one in the future and use one of the sets for active flight duty.

Before you do the repair job, take the time to draw out those fins and get us some measurements, so we can duplicate the fin can in RockSim. Since that fin can isn't in production (that I know of), we can at least duplicate it with tubes and balsa...

A Fish Named Wallyum
06-16-2006, 08:03 PM
Before you do the repair job, take the time to draw out those fins and get us some measurements, so we can duplicate the fin can in RockSim. Since that fin can isn't in production (that I know of), we can at least duplicate it with tubes and balsa...


I've already sent the Screamin Eagle stuff to Scott. ;)

tbzep
06-16-2006, 08:12 PM
Before you do the repair job, take the time to draw out those fins and get us some measurements, so we can duplicate the fin can in RockSim. Since that fin can isn't in production (that I know of), we can at least duplicate it with tubes and balsa...

I'll measure it and slap the numbers on the template. I saved it as a jpg, but the original tiff is on file at JimZ's. It is actually in cm instead of mm. Oops.

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/fintemplate.jpg

CPMcGraw
06-16-2006, 09:56 PM
I've already sent the Screamin Eagle stuff to Scott. ;)

Thanks, folks. I'll whip up a RockSim subassembly and post it tonight...

CPMcGraw
06-16-2006, 10:59 PM
I'll whip up a RockSim subassembly and post it tonight...

...And here it is...

I tried to match up the closest components from SEMROC, then converted them to plastic equivalents. This file may be off just a bit in weights, but I think it's close enough to work.

Length: 16.4"
Diameter: 0.908" (ST-8)
Fin Span: 3.62"
Weight: 1.35 oz

A8-3.......232'.......9 FPS
B4-4.......584'......33 FPS
B6-6.......610'......26 FPS
C6-7......1350'......11 FPS

All motors reach flight V in the length of a standard rod.

As you can see, this bird has a wicked mid-power deployment issue. At the low and high ends, however, the deployment velocities are within acceptable limits, and are actually quite low. Using plastic components instead of balsa, the stability margin with the C6-7 is 1.10, safely above the 1.00 minimum limit. With balsa, it was down to 0.87...

Enjoy!

Initiator001
06-16-2006, 11:17 PM
The Spartan kit (KD-3, Stellar product line) was a balsa fin version of the Screaming Eagle.

Back when Lee Piester was trying to start up a new rocket company (1987) called Enertek, one of the kits was to be a 2.5" diameter Screaming Eagle-like kit with a short boatail.

I managed to get it replaced with the INITIATOR! :D


Bob

tbzep
06-16-2006, 11:56 PM
Nice, especially when compared to mine. I'll see if I can post some pics later tonight. There's no hope for my Eagle, and no power since 2001. :(

Bill,

Did your Eagle come with a 12" or 16" chute? Was it black & yellow or red & white?

A Fish Named Wallyum
06-17-2006, 04:52 AM
Bill,

Did your Eagle come with a 12" or 16" chute? Was it black & yellow or red & white?

Red & white and I believe it was 12".

Ltvscout
06-17-2006, 08:15 AM
I've already sent the Screamin Eagle stuff to Scott. ;)
Yes, but I didn't get a drawing of the fins like Tim just sent. ;)

Buzz, pull Tim's fin drawing out of this thread to include with Bill's scans that he sent us for this set. Give me an ACK when you read this. Thanks.

tbzep
06-17-2006, 11:41 AM
I stayed up all hours of the night last night looking through all the old Centuri catalogs at Ninfinger's. Why? Well, we all do it from time to time, but I did it because my Screaming Eagle just didn't look right to me.

It was obvious when I looked at the first pic. All the images show the upper roll pattern with a white background instead of silver. I looked at several other catalog shots to see if any looked like they had the silver backed roll pattern, but none really did. I don't know if they built a catalog model that way on purpose, or if the silver bleached out in the photos, or what.

At any rate, I think I'll build a paper and balsa clone with decals having a white background. My build list is already about 20 years long, but what the hey. It will be a bit of a pain to do the fin decals. I don't really like the results of white decal paper. Any dark background shows through the material. I'll probably mask off the proper size area and leave that white when I paint the fin area, then put the decal over it.

CPMcGraw
06-17-2006, 05:05 PM
...I think I'll build a paper and balsa clone...

I also worked up the balsa and paper version, but I think you're going to be disappointed in the performance...:(

All of the deployment velocities are above 23 FPS...

Tau Zero
06-19-2006, 12:20 AM
I tried to match up the closest components from SEMROC, then converted them to plastic equivalents. This file may be off just a bit in weights, but I think it's close enough to work. [snip]Nicely done, Craig! :cool:


As you can see, this bird has a wicked mid-power deployment issue. At the low and high ends, however, the deployment velocities are within acceptable limits, and are actually quite low. Using plastic components instead of balsa, the stability margin with the C6-7 is 1.10, safely above the 1.00 minimum limit. With balsa, it was down to 0.87...Two words: "Nose weight." ;) (Oh, wait, if I read further down the thread, I see you already thought of that. :o )

I remember being especially amused when I read in the rocket's original instructions, "Even though the Screaming Eagle doesn't pass the swing test, this design is still quite stable." :eek: ;) :D

IIRC, I lost my "SE" to a Rocket-Eating Cornfield on a C6-5. Come to think of it, the wind was blowing at a pretty good clip that day, too... :rolleyes: :o


Cheers,

--Jay

Eagle3
06-19-2006, 07:23 AM
Yes, but I didn't get a drawing of the fins like Tim just sent. ;)

Buzz, pull Tim's fin drawing out of this thread to include with Bill's scans that he sent us for this set. Give me an ACK when you read this. Thanks.

Actually, if Tim could scan the plans that would be great. Sorry Bill, but your plans have some major stains on them and I've had a hard time cleaning them up. Tim's plans appear to be mint condition.

tbzep
06-19-2006, 08:36 AM
The plans that came with the kit were for the Powr Pad. The Screaming Eagle plans were missing. The Eagle plans and fin template are available at JimZ's website.

Eagle3
06-19-2006, 08:53 AM
Powr Pad will do then if it's not too much trouble.

CPMcGraw
06-19-2006, 01:09 PM
I remember being especially amused when I read in the rocket's original instructions, "Even though the Screaming Eagle doesn't pass the swing test, this design is still quite stable."

This really should have been a "red flag" in the days when this model was designed...

On the lighter all-balsa version, nose weight didn't correct the overall problem, even though it did allow the model to balance out with the heavier C6-7. That's the only reason you should add weight, BTW -- to compensate for the heavier motors. The only thing additional weight did on this model was to take the deployment velocities in the wrong direction.

This is a fin shape / fin area issue. One thing I've learned, using RockSim, about model rocket aerodynamics is that the fin area is not the most critical value; but rather, how the fin interacts with the slipstream moving around the rocket. A smaller fin with an optimized shape will have a greater effect in correcting the flight path than will a large fin with little or no optimization.

tbzep
06-19-2006, 02:33 PM
Powr Pad will do then if it's not too much trouble.

I'll work on it tonight.

A Fish Named Wallyum
06-19-2006, 03:44 PM
Actually, if Tim could scan the plans that would be great. Sorry Bill, but your plans have some major stains on them and I've had a hard time cleaning them up. Tim's plans appear to be mint condition.

Hey, what can I say? I was excited. :eek:
Not a problem. I realize that mine were a stopgap. ;)

tbzep
06-20-2006, 02:03 PM
Pics of the Powr Pad plans from the Screaming Eagle Starter Outfit, as requested.

(Images deleted...sent to Scott via email)

Ltvscout
06-20-2006, 02:14 PM
Pics of the Powr Pad plans from the Screaming Eagle Starter Outfit, as requested.
Tim,

Could you email these pics directly to plans@oldrocketplans.com? That way I can delete this post since all those files take up a fair amount of room. Thanks.

tbzep
06-20-2006, 02:23 PM
Tim,

Could you email these pics directly to plans@oldrocketplans.com? That way I can delete this post since all those files take up a fair amount of room. Thanks.

No problem.

tbzep
06-20-2006, 03:09 PM
Plans emailed...

Images from post deleted.

Ltvscout
06-20-2006, 10:29 PM
Plans emailed...

Images from post deleted.
Danke! Actually, the plans address I gave you goes to Buzz Nau who processes the files for me.

tbzep
06-29-2006, 01:11 AM
The Screaming Eagle is restored to flight status. However, I refuse to launch the bird unless I can do it on the Powr Pad. I've been to every store within 20 miles of my house and nobody carries a 6v lantern battery for the pad. What stores have you guys been to in the last year that had one of the big 6v screw terminal batteries in stock?

I've found the critters for as low as $8 online, but shipping was way more than the price of the item. I'd rather put my hands on one than to order it if possible.

http://www.cheapbatteries.com/Eveready732.jpg

http://ts.smoothcorp.com/cornerhardware/204320.400x400.jpeg

http://www.ninfinger.org/~sven/rockets/catalogs/centuri74/74cena.jpg

A Fish Named Wallyum
06-29-2006, 01:21 AM
None. I found a battery of the right size at Lowe's, but when I got home and tried to hook it up, I found that the posts were in different places relative to the holes. Let me know if you find one. I'm still in the market. ;)

hawkshobby
06-29-2006, 02:35 AM
Try this :) http://www.acehardware.com/product/index.jsp?productId=1296187&cp=1254961.1304092&clickid=lefttnav_catlinks_txt&parentPage=family&searchId=1304092

I need one too.
Mark

A Fish Named Wallyum
06-29-2006, 02:57 AM
Try this :) http://www.acehardware.com/product/index.jsp?productId=1296187&cp=1254961.1304092&clickid=lefttnav_catlinks_txt&parentPage=family&searchId=1304092

I need one too.
Mark

Excellent! That sure looks like it will do the trick. I don't know if I have an Ace in the area, but if I do, I'm dusting off my Porta-Pad to tale along for the fitting, just to be on the safe side. :rolleyes:

A Fish Named Wallyum
06-29-2006, 03:02 AM
HOLY SCHLITZ! I drive right past one on the way to the VOA for our Quark launches. If that one is closed, there's another on the other side of the park. A little out of the way for a casual drive with gas at $3+ a gallon, but I'll definitely stop for one on the way to the field on July 8th. :cool:

Tweener
06-29-2006, 08:33 AM
I don't know how large your Ace stores are, but around here I'd probably have to ask if they could special order it for me. Unfortunately I've had a problem with other low demand items in the past because they've told me they have a required minimum quantity on their orders and don't want the extra stock sitting on the shelf 'til armageddon. :(

Of course I don't see the problem with that because it's TOMORROW!!! :D

tbzep
06-29-2006, 09:24 AM
There was an ACE store about 10 miles from here. I went to have a look a few days ago and they were out of business. :mad: I'll have to find another one somewhere else.

ghrocketman
06-29-2006, 09:54 AM
Those batteries also used to be available in a 12V version with the exact same case & post dimensions. I always used to get the 12V ones instead of the 6v....they were good enough to provide reliable 3-engine cluster ignition !
I think Ray-O-Vac used to make them under the "outdoorsman" label in the late 70's through the mid 80's....the cases were metallic green in color.
I may actually still have a dead one at my dad's house.

tbzep
06-29-2006, 10:41 AM
Those batteries also used to be available in a 12V version with the exact same case & post dimensions. I always used to get the 12V ones instead of the 6v....they were good enough to provide reliable 3-engine cluster ignition !
I think Ray-O-Vac used to make them under the "outdoorsman" label in the late 70's through the mid 80's....the cases were metallic green in color.
I may actually still have a dead one at my dad's house.

They still make 12v versions. I haven't seen 6v or 12v batteries in stock anywhere locally. I'd have to replace the little continuity light with a 12v bulb if I found a 12v battery.

I won't be launching clusters off of it, so the voltage isn't needed. In fact, I won't be doing much launching on it at all unless I can find another one for display. I'll probably launch the Screaming Eagle off of it a few times and take a bunch of pictures, then put it on display until I can find another one at a decent price.

CPMcGraw
06-29-2006, 11:15 AM
I'll probably launch the Screaming Eagle off of it a few times and take a bunch of pictures, then put it on display until I can find another one at a decent price.

Here's a possibility -- build a "dummy" battery for display purposes with terminals that match properly, painted and decalled to match one of the old batteries of that era. That way, you don't have to worry about acid and other nasty compounds leaking out with time. Run wires through the hidden parts of the "battery" to a 12V power source somewhere "off camera" for those "glamour shots"...

Addendum: Inside the fake "battery", simply jumper the two terminals inside the box. Fill the box with sand or some other weight to prevent it from moving around in a gust of wind. Hook the real battery up near your hand controller, "in series". Does the same thing, but eliminates having an extra set of wires where they shouldn't be...

CPMcGraw
06-29-2006, 02:56 PM
Addendum: Inside the fake "battery", simply jumper the two terminals inside the box. Fill the box with sand or some other weight to prevent it from moving around in a gust of wind. Hook the real battery up near your hand controller, "in series". Does the same thing, but eliminates having an extra set of wires where they shouldn't be...

Yet Another Addendum...

Inside the fake "battery", permanently install 10 NiCd "C" cells in series for 12V, or 5 NiCd "D" cells for 6V. Now you can recharge that "battery" and not have anything that looks even remotely out of place...

tbzep
07-01-2006, 06:21 PM
I found a 6v Rayovac with the old style blue and yellow paint at a battery store about 40 miles from here. Cost was just under $9. I wish I could have found an original color Eveready 731, which is used in the catalog photos sans the logos and print, but this will do just fine and was my #2 choice. It's paint design and color is the same as when the Power Pad was being produced. The third option was to luck out on an old dead Mallory battery (now called Duracell). Now for the secret...the casing is plastic, not steel like the old ones. Shhh....don't tell anybody. ;)

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri9.jpg

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri14.jpg

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri21.jpg

http://i7.photobucket.com/albums/y283/tbzep/Centuri%20Power/Centuri23.jpg

Solomoriah
07-05-2006, 07:15 AM
A8-3.......232'.......9 FPS
B4-4.......584'......33 FPS
B6-6.......610'......26 FPS
C6-7......1350'......11 FPS

All motors reach flight V in the length of a standard rod.

As you can see, this bird has a wicked mid-power deployment issue. At the low and high ends, however, the deployment velocities are within acceptable limits, and are actually quite low. Using plastic components instead of balsa, the stability margin with the C6-7 is 1.10, safely above the 1.00 minimum limit. With balsa, it was down to 0.87...
The recommended B engine for the Screaming Eagle was a B4-6, which ought to resolve the deployment issue. Mine worked fine for several flights, until the motor mount separated; I eventually threw the entire model away (hey, I was a kid!)

When I bought the "outfit," Centuri offered a free rocket with purchases over $10.00 (if I remember rightly) and the Bandito was one of the options. So, I ordered the outfit and a pack of B4-6 engines, the lowest-power engine shared between the two rockets, and requested the Bandito as my gift. I was self-taught... I had no experienced adult to help me. When I launched the Eagle, it flew more or less exactly like they told me it would, and I was quite pleased. But then I shoved a B4-6 into the Bandito and launched it... I didn't think I'd ever find it! They billed the Bandito as a high-performance rocket, and to novice me it sure was.

BTW... the Eagle seemed prone to weathercocking.

CPMcGraw
07-05-2006, 10:21 AM
The recommended B engine for the Screaming Eagle was a B4-6, which ought to resolve the deployment issue...

BTW... the Eagle seemed prone to weathercocking.

Solo,

I just modified the RockSim motor file to allow for a 6-second delay in that B4. The results do not change all that much, except that the additional time allows the model to reach another 10' in total altitude, and the Dv drops only to 31 FPS.

Screaming Eagle was stable, and had sufficient fin area. Weathercocking is a good sign you have greater a than 1 calibre margin; with the B4-6, the margin is 1.28...

tbzep
07-05-2006, 10:57 AM
How about running a sim of it with an A3-4T? Maybe an A10-3T while your at it...

CPMcGraw
07-05-2006, 12:07 PM
How about running a sim of it with an A3-4T? Maybe an A10-3T while your at it...

The A10-3T is the optimal 13mm motor. Reaches 260' with a Dv of 10 FPS, and can reach safe flight V in the length of a standard rod. The A3-4T requires a 50" rod to reach that V, has a 22 FPS Dv, and only gains an additional 3' altitude.