Looking for info on Centuri Stiletto...
 

I'm looking to clone a Centuri Stiletto (2 stage, series 7 body tubes) - Unfortunately, the plans on JimZ's site do not have a parts list or fin patterns. Can anyone provide such or give me some measurements?

Thanks in advance...

Without having a kit to measure from, I would look at the "typical" body tube lengths used by Centuri, and then compare those with what we now have available through SEMROC.

Example, the booster is almost assuredly 3". Unlike Estes, who used 2.75" tubes for their 18mm motor mounts, Centuri used 3" tubes for their motor mounts.

SEMROC part equivalent is the ST-730. The coupler is called the HTC-7B.

Tricky part is the main body and the nose cone. Let's check the nose cone first...

Moldin' Oldies says their match for that cone is the PNC-76. Checking with the Centuri catalog against the balsa cones, the BC-76 is listed as 3.3" long. Remember that length. If you want a plastic cone (actually a resin cone) instead of a balsa cone, order from Mike.

If you want a balsa nose cone, then the SEMROC part is BC-733. This is a 3.3" ogive cone.

Finally, the sustainer tube. The 1978 catalog says the length was 18.25" for the model. Subtracting 6.3" (or just a tad over 6.25", notice...) from 18.25" (or 18.3") gives us a body tube length of 12". Keep in mind, Centuri was notorius for mis-stating the model lengths in their catalogs.

SEMROC sells this tube as the ST-7120.

With some 1/16" thick balsa sheet for the fins, and a few other odd parts from SEMROC, you'll have as close a clone of this model as you'll find anywhere. :D

Craig McGraw

Additional note...

I called out a single 12" tube for your clone, whereas the original model used two tubes with a coupler to make up the 12" length. Personally, I'd go with the 12" tube and a TB-7 thrust ring internally, with a 24" length of SEMROC's Kevlar thread tied around it for the shock chord mount. I'd dare to say none of us on this forum use the old Estes method for attaching mounts anymore, unless we're in some kind of competition for classic designs where "modern" construction methods are frowned on. We're a very progressive bunch of coconuts on this forum...

If you absolutely insist on staying with the old method, then you want to use another 3" length of tube for the motor mount, and a 9" length forward of that. The SEMROC part number for that tube is ST-790. The internal coupler is the HTC-7.

Go with the 12" tube. It will make the finishing stage much simpler. One less butt joint to sand and fill...

Besides, no one has to know it's not an original kit...

Craig...

Nice job, Craig. :cool: I was trying to put something together, but got frustrated when I realized that there were no fin patterns.

Actually, there are, but you have to look really hard to find them... :rolleyes:

I'm attaching a copy of the image, so you can see what I mean. You'll have to clean the image up in Photoshop, or some other image program, to get some straighter edges.

I might try to clean this image up and post the results later.

Craig McGraw

Craig,

Very nice work! It took a little digging, but I found an old one. Before I rip it open, you are right on the tubes. 3,3,9.

The nose cone is 3.0" the PNC-76. Our BC-730 is a balsa equivalent.

I will have to scan the fins and convert them to Corel to laser-cut them.

Carl

The fins are 3/32"

...And here they are!

Craig...

But that's cheating, Carl! You've got an actual kit to measure up, and I've only got a grainy set of images and a tortured mind to work with! :D :D

I was right, though, about the measurements being a tad off. I'll bet that 3.0" nose cone in your kit was a grab-what-they-had instead of what it should have been. Was there a length difference between the BC-76 and the PNC-76? I was just following the part number from Mike's list of which cones went to which kit, and interpreted the "76" as a direct carry-over from balsa to plastic.

Thanks for the "heads-up" on the balsa fin thickness. Estes would have used 1/16", but Centuri liked a more conservative, beefier fin.

Craig McGraw

Carl,

I went back to the 1978 catalog, and I see what happened. That 3.0" PNC-76 is shorter than the BC-76. But when the kit was originally designed, it was probably with the BC-76. That reference to "grab-what-they-had" is likely more accurate than guesswork.

If I were going to build the model (and I just might), I'd want the 3.3" BC-733 to be used to get it closer to the original length. The original release date was February 1, 1972, so they might have still been using balsa when the model was developed.

Vanel now has an option as to which cone to use...

Decisions, decisions... :p

Craig...

Almost all the PNC cones from Centuri are about .2 or .3 inches shorter than the original balsa ones. The ogive balsa cones were not very "mass producable" in plastic so the sharp tip was rounded, making the length shorter. They never went back and updated the kit overall lengths (or weights) on all the ones I checked that migrated from balsa to plastic nose cone.

Centuri nose cones

That makes complete sense. I forgot about the "rounded tips" on the plastic ones.

Craig...

Guess what Centuri clone just popped onto my build and review list? Do you guys have any other tricks up your sleeves?

Laser cut fin sets are now available. (Bill and Jay... the 137% upscales are also available) Ask Sheryl.

Wow! Thanks for all the information - and the fin patterns. This is great!

Carl, I will be sending an order your way soon :)

I built two of these "back in the day", and if I remember correctly, the shock cord attachment was the cut-a- slit-and-tie method. I would have traced patterns and taken measurements at the time, but never could have conceived of cloning and the type of information exchange we have available now. :eek:

Here's a pic of my original kit. The decals are pretty bad. I should have used solveset on them. Anyways, I'm not sure how well you can tell by the photo, but the Stiletto used an external coupler that was glued onto the top of the booster tube with two "pass-port" holes punched in the top where it slipped over the base of the sustainer tube. That's why the fins have those notches. I can take a photo of my kit tonight with the stages seperated. Also the booster had a thrust ring in the base similar to the Estes CC Express. Do you have this tube joiner Carl? Also, I'm very interested in that 137% upscale :)

That would be the HTC-7B coupler. I have a bunch of originals here, but I'm sure others would like these available as a mass-produced item. Do you have these available yet Carl, or plans to make them? Thanks for that Centuri>Semroc Cone Reference List. That really helps a lot.

BTW, the Black Widow also used that HTC-7B coupler.

We have them!

Hollow Tube Couplers

Thanks, Bill!

You will get two slightly different sets of the 137% upscale fins. The first has the cutouts for an external coupler which is not needed and the second is clean along the root edge with no cutouts.

Let us know how it turns out!

Carl,
You are making it far too easy to clone these old kits. I was stymied in my thoughts about a Black Widow clone because of the coupler and now you have them.
Don't tell me - you have laser-cut Black Widow fins, too?
Drew Tomko

We have them. These are of the newest iteration.
Black Widow Laser-cut Fins

D'oh!
Carl, I'm afraid to ask any more questions!
Drew

Corrected Fin Pattern for Centuri Stiletto
 

I found an error in the patterns I posted earlier. The booster fins have the grain running the wrong way. The previous image has the grain running along the trailing edge. Attached at the bottom is a corrected image.

Big oops, there... :o


Craig

Great! The pic of the fins on that page isn't showing up though.

I placed about 20 new fin sets on the site. Pictures to follow.

I wish I had known you were going to offer laser cut fins for the SST Shuttle.

I made one last winter and cutting out the fins was a chore. ;)

Thanks for putting up the Corel drawing of the fins.

Taurus laser cut fins
 

My wife informed me this evening that she was given company tickets to Six Flags that are good this Saturday or next Saturday. She was concerned that I might feel abandoned if they went this weekend, and because it's Fathers Day weekend and all, but the weather forecast looks very nice, so I told her to go ahead. What this means is that I'll have all day to finish, then fly the Semroc Taurus that I have that doesn't really exist except in the laser cut fins and all of the tubes and cones. I've been plugging away at it for a few months and I should have it ready for paint tomorrow (Thursday) night. Since I had so much trouble with the paint scheme on the 1:1 that I made with Moldin' Oldies parts, I may decide to go with the all black pods, but I'll cross that bridge when I come to it. I've got a bunch of pics for a review, so I'll try to get them posted sometime tomorrow.
Trust me. This merits a :cool:

Speaking of Moldin' Oldies parts, Mike just sent me a big update for the MO website. I'll try to get that online by the weekend. There's a lot more Estes parts available from him now.

Good luck on your Taurus, Bill! As always, send pictures when it's done.

If I get a few minutes to myself, I might also get another BT-80 based Mach 10 flying this weekend. I haven't done a small field solo launch in a long time, and the big M10 is a great rocket to have along on small fields. Gotta watch those **** gravel parking lots though. :mad:

Semroc Rules!
 

Got my order today, Carl - thanks very, very much for the Stiletto fins!

Folks, ain't no better place to get Centuri compatible parts - and the Semroc kits are absolutely superb! My orders always arrive 2 days after they are placed, with nothing missing.

Buy Semroc!

Amen to that. Carl runs a very tight operation. I get 3 or 4 email updates the same day the order is placed ending with "status: shipped". ;)

On Friday I broke down and ordered the parts for a Black Widow clone, except I goofed on the nose cone. It took less then an hour to ship from the time I ordered it, and Sheryl responded that she was able to make the nose cone switch before the order shipped. You have to be quick to keep up with Semroc!
Drew Tomko

Suggestions anyone?
 

Construction of my 1x Stiletto clone is complete - mucho thanks to Carl and Semroc! Here's a pic of the "nekkid bird", built with Semroc parts and a left-over Centuri PNC-76:



Being somewhat of a purist, I would like the rocket to have the same paint scheme as shown in this catalog. It's rather complex, and I am trying to get some idea as to the best way to produce the white areas on the fins... Masking would take lots of time and has the potential for bleeding, while paper or label overlays add weight and may not stick well to the primer/paint.

What do you folks think?

Very sharp looking. I think you could easily duplicate the catalog scheme with plain white decal paper. Craig probably has some Bel paper that he's looking to unload. (Ducking and running.) I know Craig doesn't think much of the Bel paper these days.
I think you could easily do that scheme with well burnished, good quality masking tape. That blue tape from 3M isn't cheap (compared to regular masking tape,) but it gives a nice crisp line if you take the time to do the edges. Make the white the second color.
My $.02.

Dangit! I'm gonna have to get the stuff to make the upper stage. I still have the booster for a Stilleto I built back in the '80s. I really liked the looks of that rocket.

Joe W

Another idea is to use white trim monokote. You could cut out the pieces in no time. When you peel the backing off dip the monokote in some water with a few drops of dish washing degergent before applying. That way you can slide it around a little to get it in position. When the water dries, wah la! It's done!

Good one. I've never been able to find Monokote. Where do you get it?

You can find Trim Monokote in hobby shops that cater to R/C flyers. It comes in long sheets in a bunch of colors. I've used the metallic silver and it works great. Trim Monokote is self adhesive as opposed to the regular stuff which has to be applied with heat.