Payloader II capsule length

[Earl]

Folks--

This is my first post here, so any and all helpful direction is appreciated.

In recent months I've been getting back into a bit of 'model' rocketry (after many years of high-power and high-power video production). Alas, family health issues the past several years have greatly curtailed my ability to travel to LDRS each year. Having been involved with high power since the late 80's (after getting into model rocketry originally in the early 70's), I'm turning some interest back to my 'roots' these days and re-flying some of my classics (Centuri Orion, Nike Smoke, Twister, etc.) since my local flying field will not support my high power endeavors.

Anyway, to the question at hand. I'm 're-creating' my Centuri Payloader II that I lost many years ago (late 70's) when it floated over a swamp never to be recovered again. I have all the parts I need to do the build (even some vintage clear plastic capsule tubing), but therein lies the problem. I do not know the proper (full) length the payload tube should be.

I've checked the various (very wonderful!) sites that provide plans for our beloved 'oldies' and the Payloader II plans there state a capsule length of just 2.5 inches. To my recollection (and I could be wrong), but that length seems a bit short. Maybe that measurement is the actual 'useful payload' length less the space taken up by the balsa tube coupler and the nosecone shoulder.

Does someone out there have a 'bagged' Payloader II or a vintage built-up kit that they can measure the 'actual' length of this tube for me? The listed 2.5 inches in the archived plans just seems too short, but, as I said, I may just be remembering wrong. Overall length of the finished rocket is (according to the kit liner card) 18.5 inches. Main body tube is 10.5 inches and the nosecone is 4 inches, which would SEEM to 'leave' 4 inches for the payload tube, but that seems a bit too long (not sure either how that full-length measurement for the rocket is taken, since the fins do run somewhat past the end of the bodytube).

So, I'm somewhat in a bit of quandry here and do not really want to simply 'guess' at the length. Would really like to be 'right' and have a faithful reproduction of my old trusty Payloader.

Thanking any and all in advance for your assistance,

Earl

[tbzep]

Hi Earl,

I know you've met thousands while documenting HPR launches and won't remember, but I'm glad to have met you a few times in TN and SC. I hope you video the launches of your classic rockets and share them with us.

I don't have the measurements you need, but there are some here that will chime in with the information you need before long. If not, we'll dig up the info somewhere. :)

[Carl@Semroc]

Earl,

The major parts are as follows:

CPT-102 2.5" Long
ST-1010 10.5" Long (Semroc ST-10105)
PNC-103 4.1" Long (Semroc BC-1041P)

We are trying to get a quote on CPT-10 and several others, but holidays slowed that down.

[Ltvscout]

Earl,

The major parts are as follows:

CPT-102 2.5" Long
ST-1010 10.5" Long (Semroc ST-10105)
PNC-103 4.1" Long (Semroc BC-1041P)

We are trying to get a quote on CPT-10 and several others, but holidays slowed that down.
Thanks, Carl. As you know, I'm biding my time waiting for the Semroc release of the Payloader II clone since it was my first kit. :D

Earl, welcome to YORF!

[Ltvscout]

Earl,

Besides the info that Carl posted, you can find the plans and scans of the Payloader II here at my Ye Olde Rocket Plans site:

http://www.oldrocketplans.com/centuri/cenKC-20/cenKC-20.htm

[Earl]

All-

Thanks for all the responses and feedback. I had checked those plans earlier and, as stated in my original post, that 2.5 inch length (thinking back to my original Payloader II) just seemed a bit too SHORT. I'm thinking back now like 28 years ago when I lost this rocket over a swamp, so my memory *could* be off <g>.

If everyone believes that IS in fact the correct length, I'll go with that (I've got 10 inches of uncut vintage CP-10 tubing from Centuri).

But...if someone DOES have an unbuilt Payloader II kit around (or even a vintage built one) that they can VERIFY that length, it'd be mucho appreciated.

BTW, Carl, the main tube and motor mount kit for this Payloader II re-creation was just recently purchased from Semroc! (several orders to ya in the past month or so... VERY satisfied customer!!!).

Earl

[Carl@Semroc]

But...if someone DOES have an unbuilt Payloader II kit around (or even a vintage built one) that they can VERIFY that length, it'd be mucho appreciated.The dimensions were taken from an unopened kit. It was the later model with plastic nose cone.

BTW, Carl, the main tube and motor mount kit for this Payloader II re-creation was just recently purchased from Semroc! (several orders to ya in the past month or so... VERY satisfied customer!!!).

EarlThanks for the kind words! They keep us going around here.

[Earl]

Carl (& All)--

Ok, sounds good to me. That was the verification I was looking for. As I said, I was drawing from 28 year old+ memories, but it just *seemed* like a longer capsule tube length than the 2.5 inches listed.

BTW Carl, I don't suppose there's a chance you *might* already have laser-cut fin sets for the Payloader II (and not yet announced)? About ready to cut those out from my pattern, but if you already have some 'in stock', that would certainly be a much easier route!


Thanks again,

Earl

[falingtrea]

Carl (& All)--

Ok, sounds good to me. That was the verification I was looking for. As I said, I was drawing from 28 year old+ memories, but it just *seemed* like a longer capsule tube length than the 2.5 inches listed.

l

Heheh, you know the stock answer for that, dont' ya Earl?

"You were a lot smaller then and everything looked bigger" :) :p :D :rolleyes:

[Earl]

All-

Well, just when I thought we had put this one to bed, I have some 'conflicting' data.

I rummaged around the other night and remembered that I had purchased an old Centuri starter kit remnants off eBay about a year ago, which looked to be the 'remains' of a 1969 Centuri starter set which featured two kits: the Payloader II and the Javelin. Also had the old Lectra Line controller (actually, two of them), a pack of chute wadding, etc. (and about six motors as well, all later 1969 vintage; some motor 'sales' still slip through on eBay, thank goodness!).

Anyway, the two kits in this box of stuff were partially built, with all the Payloader parts included, which appeared to have been nearly completely assembled and painted at one time (but poor construction).

So, I pulled this stuff back out last night and guess what? The clear payload tube length on that Payloader II was 3.5 inches long, compared to the 2.5 inches reported by others.

BUT ... this 3.5 inches appeared to be about the length I remember that payload section being on my original Payloader II.

Now, my original Payloader II (that I purchased in '76) included the newer plastic nosecone and this older one that I pulled back out last night is the older kit with the balsa cone (and the different-cut two piece fins). However, I would *think* that even though they changed to a plastic nosecone (which is the same basic style and length of the older balsa one) that the *other* dimensions of the kit would stay the same, including the payload capsule length.

Sooooo ... it appears that we maybe need a 'tie-breaker' out there from someone ELSE who has an unbuilt Payloader II (or vintage 'built' one) and can provide a THIRD datapoint on this payload tube measurement to see which may be the correct length.

So, the question is: Is it 2.5 inches or is it 3.5 inches??

Hate to be picky, but I want to get it right (and I assume Carl would want to make sure his re-issue kit is correct as well).

Thanks!!!

Earl

[Ltvscout]

So, I pulled this stuff back out last night and guess what? The clear payload tube length on that Payloader II was 3.5 inches long, compared to the 2.5 inches reported by others.

BUT ... this 3.5 inches appeared to be about the length I remember that payload section being on my original Payloader II.

Now, my original Payloader II (that I purchased in '76) included the newer plastic nosecone and this older one that I pulled back out last night is the older kit with the balsa cone (and the different-cut two piece fins). However, I would *think* that even though they changed to a plastic nosecone (which is the same basic style and length of the older balsa one) that the *other* dimensions of the kit would stay the same, including the payload capsule length.

Sooooo ... it appears that we maybe need a 'tie-breaker' out there from someone ELSE who has an unbuilt Payloader II (or vintage 'built' one) and can provide a THIRD datapoint on this payload tube measurement to see which may be the correct length.

So, the question is: Is it 2.5 inches or is it 3.5 inches??
That Payloader II with the balsa cone you have is an original issue. That's what I had as my first rocket. I still have the bottom half, but unfortunately the payload section floated away in the 70's due to shock cord separation. Since you have the balsa cone version you should measure the cone to verify it's the BC-103 version which is Semroc's BC-1039. My memory of my Payloader was that it had a longer payload tube than 2.5", but then again, I was only 9 or 10 at the time. ;)

[Carl@Semroc]

The original Payloader II with balsa nose cone is the one we will do. The picture in the 1969 catalog shows the balsa nose cone and a 3.5" clear tube. The one I have is the 1973 copyright version.

[Earl]

Carl--

Can I get a clarification on your statement there? Are you saying that at some point you have measured a Payloader II kit and the payload tube WAS 3.5" (and hence that's what your re-issue kit will have)?

But that your '1973' version (which is the same version, with plastic nosecone, I had) measures out with a 2.5" payload tube? Is that a correct summary?

I'm kinda wondering if that 2.5" tube in your 1973 version might not be an 'oddball'. Obviously, I'll take your word for it that it does in fact measure out to 2.5", but that does seem awful short compared to what I remember it being. If one does some 'back of the envelope' photo measurement extrapolation from the Payloader II photos in the Centuri catalogs and from the kit face card, kit instructions, etc., the calculations show a measurement of 3.5" (or thereabouts) as compared to 2.5".

Again, I'll ask if someone out there has an unbuilt Payloader II they can take a THIRD measurement of for us, it would be most appreciated.

Thanks! :)

[SEL]

OK, you got it - the clear tubes in both of the kitst that I bought from Comonwealth Displays back in the late 80's measure (d) 2.5". I was quite disapointed, as I was expecting the longer payload section as shown in the catalogue. The 2.5" just doesn't look right.
On a sadder note, loike Scott H., the payload section from the kit that I built was left hanging in a tree.

Sean

Carl--

Can I get a clarification on your statement there? Are you saying that at some point you have measured a Payloader II kit and the payload tube WAS 3.5" (and hence that's what your re-issue kit will have)?

But that your '1973' version (which is the same version, with plastic nosecone, I had) measures out with a 2.5" payload tube? Is that a correct summary?

I'm kinda wondering if that 2.5" tube in your 1973 version might not be an 'oddball'. Obviously, I'll take your word for it that it does in fact measure out to 2.5", but that does seem awful short compared to what I remember it being. If one does some 'back of the envelope' photo measurement extrapolation from the Payloader II photos in the Centuri catalogs and from the kit face card, kit instructions, etc., the calculations show a measurement of 3.5" (or thereabouts) as compared to 2.5".

Again, I'll ask if someone out there has an unbuilt Payloader II they can take a THIRD measurement of for us, it would be most appreciated.

Thanks! :)

[Carl@Semroc]

......If one does some 'back of the envelope' photo measurement extrapolation from the Payloader II photos in the Centuri catalogs and from the kit face card, kit instructions, etc., the calculations show a measurement of 3.5" (or thereabouts) as compared to 2.5".That is what I did. They offered both the 2.5" and 3.5" CPT as parts in the 69 catalog. The overall length of the Payloader II stayed the same in the specifications.

[Carl@Semroc]

BTW Carl, I don't suppose there's a chance you *might* already have laser-cut fin sets for the Payloader II (and not yet announced)? About ready to cut those out from my pattern, but if you already have some 'in stock', that would certainly be a much easier route!


Thanks again,

EarlSorry for the delay. I missed this post the first time. We have the laser-cut fins. Like man others, it takes time to get them online.

[SEL]

Sorry for the delay. I missed this post the first time. We have the laser-cut fins. Like man others, it takes time to get them online.


Ahhhh, more things to buy with the gift certificate my brother gave me. I'm going to have to start a list.. I don't see the Series 10 plastic tube listed yet - are they available?

Sean

[Carl@Semroc]

Ahhhh, more things to buy with the gift certificate my brother gave me. I'm going to have to start a list.. I don't see the Series 10 plastic tube listed yet - are they available?

SeanWe are still trying to get a response for quotes for following:


Our No. Nom O.D. Nom I.D. Wall Len.

CPT-10180 1.000" 1.030" 0.015" 18"
CPT-13180 1.300" 1.330" 0.015" 18"
PST-20 0.710" 0.736" 0.013" 18"
PST-50 0.950" 0.976" 0.013" 18"
PST-59 1.533" 1.585" 0.021" 18"
PST-60 1.595" 1.637" 0.021" 18"
PST-65 1.750" 1.796" 0.023" 18"

Problem seems to be with exact mandril sizes.

[Earl]

OK, you got it - the clear tubes in both of the kitst that I bought from Comonwealth Displays back in the late 80's measure (d) 2.5". I was quite disapointed, as I was expecting the longer payload section as shown in the catalogue. The 2.5" just doesn't look right.
On a sadder note, loike Scott H., the payload section from the kit that I built was left hanging in a tree.

Sean


Thanks for the 'datapoints' there, Sean. Hmmmm....so it seems that the Payloader II kit (at various times) came with longer (and then, apparently, later) came with a shorter payload tube.

I presented the question to Danny Sagestetter the other day via email and he said he thought it was 3.5" also, and he has an unbuilt Payloader II, but could not get his hands on it right away.

I agree with Sean: I think the 'original' 3.5" length 'looks' better than the shorter 2.5" length would look. Not sure why they would have changed it in later years, but apparently they did.

Thanks again, Sean, for supplying your kit measurements and for all others with their input.

And Carl... I will look for those Payloader II fin sets on the Semroc website. Those will be mucho helpful!!

Earl

[tbzep]

Earl,

Why don't you make two payload sections...one with each size clear tube? Better yet, build two rockets, one with the 2.5" tube and one with the 3.5". Carl's parts are inexpensive and the rocket is a simple enough build that it wouldn't take more than a few minutes to de each step twice instead of once. :)

[Earl]

Earl,

Why don't you make two payload sections...one with each size clear tube? Better yet, build two rockets, one with the 2.5" tube and one with the 3.5". Carl's parts are inexpensive and the rocket is a simple enough build that it wouldn't take more than a few minutes to de each step twice instead of once. :)

Yeah, that certainly would be pretty easy to do. I've got enough vintage Centuri CP-10 clear plastic tubing to do both.

My main 'interest' in asking here in the forum to begin with though was an attempt to be 'authentic' with the reproduction of my original Payloader II. I have an original Centuri plastic nosecone (like the one mine had) and the vintage clear pastic tubing, and recently ordered the body tube and engine mount for it from Carl, so I was 'ready' to go, but just didn't know that payload tube length.

Kinda interesting to see that, over the years, Centuri apparently changed the length in later years to the shorter 2.5" payload tube. Not sure why. It would seem to make that design look a bit on the 'stumpy' side, but that may be a matter of personal taste.

But I certainly do appreciate the info and posts from everyone. Very helpful and interesting!

Earl

[tbzep]

That's happened with several rockets over the years. Two classics that come to mind are the Centuri Taurus that had different shaped nosecones on the nacelles and the Estes Cherokee-D which had a body tube that was lengthened from 16.35" to 18" at some point. The longer tube looked odd to me. Several kits switched from balsa to plastic nosecones also.

[John Brohm]

That's happened with several rockets over the years. ... Several kits switched from balsa to plastic nosecones also.

You're right about that one, Tim;

Perhaps the all-time classic is the #0846 Eclipse, which managed to make the full progression from balsa, to blow molded, to injection molded noses before its day was done.

[A Fish Named Wallyum]

That's happened with several rockets over the years. Two classics that come to mind are the Centuri Taurus that had different shaped nosecones on the nacelles and the Estes Cherokee-D which had a body tube that was lengthened from 16.35" to 18" at some point. The longer tube looked odd to me. Several kits switched from balsa to plastic nosecones also.

You think the tube looked odd, you should have seen the version I made with the long tube AND a Black Brant nose cone. :rolleyes:
It looked right at the time. :D

[Carl@Semroc]

Kinda interesting to see that, over the years, Centuri apparently changed the length in later years to the shorter 2.5" payload tube. Not sure why. I think Centuri was much more cost conscious in the early 1970's after Damon. They could have had a surplus of 2.5" or were trying to burn the part off. It was gone by 1980 and the 3.5" was still around. I definitely like the longer section.

John Dyer uses the clear tubing well in his new Delta Syx.

[tbzep]

You're right about that one, Tim;

Perhaps the all-time classic is the #0846 Eclipse, which managed to make the full progression from balsa, to blow molded, to injection molded noses before its day was done.

I wasn't even thinking about injection vs. blow molded, but you are right. I guess the most obvious examples would be the heavy PNC-60AH cones in the original Citation Patriot and Citation Red Max, which eventually changed to blow molded cones which probably weigh about half.

Hmmm. I have both cones and a postal scale. Yep. The unpainted injection molded with screw eye is about 1.5 oz and the painted blow molded cone with shock cord and shroud lines draping over the side is 0.7 oz. :)

[Tau Zero]

John Dyer uses the clear tubing well in his new Delta Syx.So... did you manage to finally get some CPT-10, and is it *officially* "in stock" yet? Or not?

Inquiring (obsessive-compulsive) minds want to know,

[Carl@Semroc]

So... did you manage to finally get some CPT-10, and is it *officially* "in stock" yet? Or not?

Inquiring (obsessive-compulsive) minds want to know,Not yet. Still trying to find a source.

[John Dyer]

I wasn't even thinking about injection vs. blow molded, but you are right. I guess the most obvious examples would be the heavy PNC-60AH cones in the original Citation Patriot and Citation Red Max, which eventually changed to blow molded cones which probably weigh about half.

Hmmm. I have both cones and a postal scale. Yep. The unpainted injection molded with screw eye is about 1.5 oz and the painted blow molded cone with shock cord and shroud lines draping over the side is 0.7 oz. :)


My first rocket was a Citation Red Max with one of those nose cones. On about the 50th flight the model didn't eject the cone and the rocket streamed in, hitting a sidewalk. The only damage to the cone was a slight dent and a crack. Of course, the rest of the model was destroyed. Yes, it was sometimes good that parts are changed :rolleyes: