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  #1  
Old 01-02-2019, 04:28 AM
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blackshire blackshire is offline
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Default MPC/AVI P-Chuter plans

Hello All,

The MPC/AVI P-Chuter, a parachute duration rocket (it won a bronze medal at the 1972 World Championships for Space Models at Vrsac, Yugoslavia), is another Miniroc (13 mm motor powered) kit for which no plans appear to exist, *but*... I may have found a way around this problem (and I'm hoping that someone else here on YORF could confirm it); it goes like this:

The P-Chuter is listed in the 1973 AVI catalog (see: http://www.ninfinger.org/rockets/nostalgia/73avi04.html ). The description of the kit is so complete (length: 305 mm [12"], diameter: 20 mm [0.79"--actually, 0.787", as in the Quest catalogs], 10-degree boat-tail, etc.) that, given a fin pattern, anyone could clone the P-Chuter, and:

While I haven't come across a fin pattern for the P-Chuter, I suspect that I may already have one--the fins on G. Harry Stine's Paradigm-5 mini motor design (see: http://www.apogeerockets.com/educat...wsletter225.pdf [it can also be seen in most editions of his "Handbook of Model Rocketry," in the chapter titled, 'Model Rocket Aerodynamics') look like the P-Chuter's fins. He was "enamored with" clipped delta fins of those proportions, and those particular clipped delta fins' dimensions (root chord: 1", tip chord: 0.5", root-to-tip span: 1") look right for the P-Chuter. If anyone here has a P-Chuter fin pattern, or even "just" has a built P-Chuter and could measure its fin dimensions, we could know for sure. Also:

The P-Chuter used a 3-caliber, injection-molded paraboloid nose cone (whose exposed portion was 2.53 [64.27 mm] long). This was the same one that Quest used (under the name of PNC20) in their earlier kits (see: http://www.ninfinger.org/rockets/ca.../93quest22.html and http://www.ninfinger.org/rockets/nostalgia/92qst16.html ). The newer, replacement nose cone that Quest now uses may be the same length (if not, its length is very similar), but it is a blow-molded, one-piece nose cone, and it may be a tangent ogive rather than a paraboloid, although it's rather hard to tell, from the picture on the Quest website (see: http://www.questaerospace.com/20mm_...5_16432958.aspx ).

I hope this information will be useful, and many thanks to anyone who can help!
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Old 01-02-2019, 12:16 PM
jdbectec jdbectec is offline
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The plans for that were published somewhere. MRM or maybe The Handbook of Model Rocketry.
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  #3  
Old 01-02-2019, 07:33 PM
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blackshire blackshire is offline
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Quote:
Originally Posted by jdbectec
The plans for that were published somewhere. MRM or maybe The Handbook of Model Rocketry.
The P-Chuter plans aren't in the "Handbook of Model Rocketry." I have owned all seven editions (and I currently have the fourth through the seventh editions), and the plans aren't in any of them. There is, however, a photograph in a few of them (the fourth and fifth editions, at least--I just checked mine) that shows Ellie Stine prepping her P-Chuter for its Bronze Medal Parachute Duration event flight at the 1972 Vrsac, Yugoslavia championships, and:

Looking at the picture, and comparing its fins with the Paradigm-5's fins in the "Model Rocket Aerodynamics' chapter of Stine's "Handbook of Model Rocketry" (see: http://www.apogeerockets.com/educat...wsletter225.pdf ), I *think* they're the same fins (Stine was a consultant to MPC at around that time), but without measurements of the P-Chuter's fins, it's impossible to be sure. Maybe the NAR's journal (I don't know what its title was then), in the article that covered the 1972 Vrsac championships, included plans for the P-Chuter?
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http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
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Old 01-04-2019, 11:17 PM
Faithwalker Faithwalker is offline
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Quote:
Originally Posted by blackshire
The P-Chuter plans aren't in the "Handbook of Model Rocketry." I have owned all seven editions (and I currently have the fourth through the seventh editions), and the plans aren't in any of them. There is, however, a photograph in a few of them (the fourth and fifth editions, at least--I just checked mine) that shows Ellie Stine prepping her P-Chuter for its Bronze Medal Parachute Duration event flight at the 1972 Vrsac, Yugoslavia championships, and:

Looking at the picture, and comparing its fins with the Paradigm-5's fins in the "Model Rocket Aerodynamics' chapter of Stine's "Handbook of Model Rocketry" (see: http://www.apogeerockets.com/educat...wsletter225.pdf ), I *think* they're the same fins (Stine was a consultant to MPC at around that time), but without measurements of the P-Chuter's fins, it's impossible to be sure. Maybe the NAR's journal (I don't know what its title was then), in the article that covered the 1972 Vrsac championships, included plans for the P-Chuter?


Fortunately, after your mention of it and after looking through my old copies of Model Rocketeer Magazine, I learned that the first World Championships for Space Models held in Vrsac, Yugoslavia, was from September 22-25, 1972. In the January 1973 issue of Model Rocketeer Magazine on page 14 are listed the World Championship results, indeed, showing Ellie Stine as the 3rd place individual Parachute Duration winner. On page 15 of that same issue, two bonus plans of two World Championship Award Winning Models are provided: the first place Swift boost glider winning, Grebix b/g plans, and the third place Parachute Duration winning, AVI P-Chuter plans, drawn by G. Harry Stine himself.

The following is a jpg image of the AVI P-Chuter plans from the January 1973 issue of Model Rocketeer Magazine. In addition, I have attached a pdf file of both bonus plans provided for your reference. I discovered that there is an error in the AVI P-Chuter plans for the motor tube size. The plans show the motor tube size as, "AVI T-19 x 2.25 Tube", but it should read, "AVI T-14 x 2.25 Tube." The T-14 is 14 mm (0.551 in.) outside diameter and 13 mm (0.511 in.) inside diameter x 2.25 inches long.

Hope this helps.

Kind regards,

Jeff Jenkins
aka: Faithwalker
NAR #46879 SR
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Last edited by Faithwalker : 01-07-2019 at 06:10 PM.
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  #5  
Old 01-05-2019, 01:57 AM
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blackshire blackshire is offline
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Quote:
Originally Posted by Faithwalker
Fortunately, after your mention of it and after looking through my old copies of Model Rocketeer Magazine, I learned that the first World Championships for Space Models held in Vrsac, Yugoslavia, was from September 22-25, 1972. In the January 1973 issue of Model Rocketeer Magazine on page 14 are listed the World Championship results, indeed, showing Ellie Stine as the 3rd place individual Parachute Duration winner. On page 15 of that same issue, two bonus plans of two World Championship Award Winning Models are provided: the first place Swift boost glider winning, Grebix b/g plans, and the third place Parachute Duration winning, AVI P-Chuter plans, drawn by G. Harry Stine himself.

The following is a jpg image of the AVI P-Chuter plans from the January 1973 issue of Model Rocketry Magazine. In addition, I have attached a pdf file of both bonus plans provided for your reference. I discovered that there is an error in the AVI P-Chuter plans for the motor tube size. The plans show the motor tube size as, "AVI T-19 x 2.25 Tube", but it should read, "AVI T-14 x 2.25 Tube." The T-14 is 14 mm (0.551 in.) outside diameter and 13 mm (0.511 in.) inside diameter x 2.25 inches long.

Hope this helps.

Kind regards,

Jeff Jenkins
aka: Faithwalker
NAR #46879 SR
Oh my--talk about "Ask and ye shall receive...seek and ye shall find...knock, and the door shall be opened unto you"--indeed it *does* help; THANK YOU!!! You confirmed what I had suspected, that the P-Chuter's fins and the Paradigm-5's fins were the same. Thank you also for pointing out the T-19 motor mount tube error (that is interesting, that the MPC/AVI 13 mm motor mount tube's 0.551" O.D. [Outside Diameter] and 0.511" I.D. are just a smidgen different from Centuri's #5 tubing [see: http://www.ninfinger.org/rockets/no...a/72cen058.html ] and Estes' BT-5 tubes [see: http://www.ninfinger.org/rockets/ca...79/79est62.html ]). The differences are so small that Estes BT-5, and the equivalents available from ASP, BMS, Semroc, and other manufacturers could be used to build a clone of the P-Chuter. Also:

I found a Quest 3-caliber, two-piece PNC-20 (for the P-Chuter's 20 mm O.D. body tube) paraboloid nose, which was injection-molded using the MPC/AVI tooling that Quest had acquired and used in the early 1990s (see: http://www.ninfinger.org/rockets/ca.../93quest22.html ). I also dug out a new (current-production), one-piece, tangent ogive, blow-molded PNC-20 (see: http://www.questaerospace.com/20mm_...5_16432958.aspx ), and I compared their appearances and lengths. The old PNC-20 looks very much like a tangent ogive, but its paraboloid profile is discernable. The new blow-molded PNC-20 is a tangent ogive, but both nose cones are the same length (to what can be discerned with the naked eye), so a P-Chuter clone could use the new PNC-20 without looking really noticeably different from the old kits (and the clones' performance would probably be "equally similar" to that of the P-Chuter kits).
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http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
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  #6  
Old 01-05-2019, 08:33 AM
chrism chrism is offline
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The AVI P-Chuter looks very similar to the Paradigm-5.
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Old 01-05-2019, 08:38 AM
jdbectec jdbectec is offline
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Thanks for finding those plans. I knew I had copied them from somewhere. Unfortunately I can't access my stuff as it is in storage due to a recent house fire that destroyed the majority of my rocketry collection.

Yes Jason the earlier nose comes are very different than the current Quest ones. The current cones are also heavier, about 6-7 grams in weight. Most likely for stability reasons.
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Old 01-05-2019, 10:04 AM
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You certainly nailed the fin pattern in your original post, Blackshire.
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Old 01-06-2019, 12:16 AM
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blackshire blackshire is offline
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Quote:
Originally Posted by chrism
The AVI P-Chuter looks very similar to the Paradigm-5.
Yes; thinking along these lines, the Paradigm-5 (here are plans and part sources, for it *and* for an up-scaled, 18 mm motor-powered variant: http://www.apogeerockets.com/educat...wsletter225.pdf ) could be thought of as a Streamer Duration 'partner' of the P-Chuter, a Parachute Duration design, both of which use 13 mm mini-motors.
Quote:
Originally Posted by jdbectec
Thanks for finding those plans. I knew I had copied them from somewhere. Unfortunately I can't access my stuff as it is in storage due to a recent house fire that destroyed the majority of my rocketry collection.

Yes Jason the earlier nose comes are very different than the current Quest ones. The current cones are also heavier, about 6-7 grams in weight. Most likely for stability reasons.
I harbor similar fears (for myself and for my rocket items and my books), from earthquakes (and long before the big shaker down around Anchorage in November)! But:

Actually--in terms of appearance--the old (from MPC/AVI injection molds) and the current (blow-molded) Quest PNC-20 nose cones look very much alike (I was rather surprised at their close resemblance myself, when I compared them side-by-side a few days ago). The old PNC-20 is definitely paraboloid in shape, but even when it's held next to the tangent ogive current Quest PNC-20, the old PNC-20's "paraboloidality" isn't glaringly obvious, as it looks like a tangent ogive. When it's socketed into a T20 body tube, though, its paraboloid curve becomes evident, as it intersects the tube at a shallow angle (rather than "flowing" smoothly to meet the edge of the tube, as the tangent ogive PNC-20's curve does). Also:

I didn't weigh both nose cones, much less compare their respective masses, but I'm glad to know that the new, blow-molded PNC-20 is somewhat heavier (I noticed--without making a comparison--that both versions are quite lightweight).
Quote:
Originally Posted by astronwolf
You certainly nailed the fin pattern in your original post, Blackshire.
Thank you--looking at the Paradigm-5 drawing and the P-Chuter photographs in Stine's Handbook (he also mentioned preferring that clipped delta fin configuration, for performance, in the book), the possibility that both rockets had the same fins just kept "mentally itching." But Faithwalker (Jeff) deserves the credit, because he found, scanned, and posted (and provided the part designation correction, plus information on the P-Chuter design's history) here on YORF, for all of us.
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
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  #10  
Old 01-07-2019, 05:57 PM
Faithwalker Faithwalker is offline
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Quote:
Originally Posted by blackshire
...But Faithwalker (Jeff) deserves the credit, because he found, scanned, and posted (and provided the part designation correction, plus information on the P-Chuter design's history) here on YORF, for all of us.


No problem. Glad to help out.

You may also find some interest in the following AVI advertisement from the inside front cover of the April 1973 issue of Model Rocketeer Magazine. It shows built up versions of some newly introduced AVI kits including the P-Chuter, Mini-Hawk, Space Angel, Nike-Tomahawk, Sounder, and U.S.S. Eagle. I'm curious if anyone actually purchased and received any of these kits. All we know for sure is that Ellie Stine flew the P-Chuter at the first World Championship for Space Models, and that G. Harry Stine drew up the plans for it. It would be nice to know, if anyone can comment, whether they actually had/have any of these kits from AVI.

Kind regards,
Jeff Jenkins
aka: Faithwalker
NAR #46879 SR
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Last edited by Faithwalker : 01-07-2019 at 06:25 PM.
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