Hello All,

I have three questions about the Estes Leprechaun (No. 0887). It was originally 8.2" long when it was introduced in 1988 (see: http://www.ninfinger.org/rockets/no...a/88est014.html ), but the very next year it was increased to 10.25" in length (see: http://www.ninfinger.org/rockets/nostalgia/89est14.html ), the same as the Gnome. It could reach 900 feet, 100 feet more than the Gnome. Its recommended engines list was more restricted than the Gnome's (which is 1/2A3-2T, 1/2A3-4T, A3-4T, and A10-3T)--the Leprechaun's list included only the 1/2A3-4T and the A3-4T. The questions are:

[1] In the original (1988) Leprechaun kit, how far back from the front edge of the body tube was the front edge of the plastic upper launch lug/shock cord anchor ring located? (In the 1989 and later Leprechaun kits, the front edge of the ring was located 1.5" back, as in the Gnome kit.)

[2] Did the original 8.2" long Leprechaun have stability issues? (This could be the reason why the heavier A10-3T was not included in its recommended engines list. It might also be why the model's length was so soon increased to 10.25" to match the Gnome's length, although enabling both kits to use the same body tube length in order to reduce the number of different parts in Estes' inventory [the Gnome also used a white body tube at that time] might have been the reason.)

[3] Did the original (1988) Leprechaun use a 6" long BT-5 body tube? (The 2.05" difference in length between the Leprechaun and the Gnome, when subtracted from the 8" length of the Gnome's body tube, yields 5.95", which is very close to 6".)

Many thanks in advance to anyone who can help.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
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NAR #54895 SR

When I compared both the 88 and 89 Leprechaun's the photos look identical in both catalogs. I do not see the 89 picture look any longer.

However in the 88 catalog, Estes lists the Gnome's diameter as 0.544" and the Leprechaun's as 0.541." What happened to the 0.003"?

I really don't know if anyone can go by catalog info to get precise measurments. Who knows, maybe in the 89 description of the Leprechaum, they combined the Gnome info?

Try this to see what body tube was used on Leprechaun http://www.rocketshoppe.com/info/Es...be_List_3.1.pdf

Hope this helps.


Chris M.

Chris;

You have a fair point about the wandering airframe ODs, and most likely the 0.544" reference is the one in error. The dimensions for BT-5 are listed in the 1974 Parts Catalog as ID = 0.515"/OD = 0.541"/ WT = 0.013"; the important point here being that all the math adds up. One finds precisely the same dimensions for BT-5 in both the 1988 and 1989 catalogs in the parts section. So we have to conclude the 0.544" is likely wrong.

Centuri Series 5 airframe was published as having an ID = 0.515" but an OD of 0.543" for a wall thickness of 0.014"; again the math adds up, and I see that our trusty friends at Semroc use these same dimensions for their reproduction Series 5 airframe.

Getting dimensions listed incorrectly on kit face cards seems to happen from time to time. The best example I like is #1941 Fox Fire; here the face card lists the airframe OD as 0.976" (BT-50), when in fact the kit is supplied with a BT-20. So this one's quite off.

Coming to Blackshire's question, while I can't say I've ever seen a #0887 Leprechaun specifically and only from 1988, I'm doubting whether the initial release had a shorter airframe than the Gnome. The only way to tell, of course, is if in fact there's a short one out there, and hopefully if such a beast exists someone might report in. But there's several reasons why I'm a skeptic.

The PNC-5 nose cone used in the kit is 2.125" long. The plastic fin can has a total length of 1.5"; 0.5" of this length is the fin sweepback, base to tip (means the can itself is 1" long). What length of BT-5 makes 8.2" (I'm guessing more like 8.25") work?

We could imagine the airframe being installed with the aft end flush with the same station as the fin tips. For an 8.25" overall length, the BT would be 8.25" - 2.125" = 6.175". Or, perhaps the BT might be installed flush with the end of the fin can; then the BT would be 8.25 - 2.125 - 0.5 = 5.625". Or, perhaps the BT was to be installed as per the 1989 instructions - 3/8" (0.375") exposed from the aft end of the fin can base. Then the BT would be 8.25 - 2.125 - 0.125 = 6.00"

The BT-5 parts in vogue were:

030301 WBT-5 8.00" as used in the original Gnome
030302 BT-5 18.00" as used in K-33 Trident
030303 BT-5 6.00" as used in #0866 Mini Tri-Pak
030304 BT-5BJ 2.00" as used in TK-1 Mosquito
030305 BT-5 4.00" as used in #0866 Mini Tri-Pak
030306 BT-5P 5.1" as used in K-17 Aerobee
030308 BT-5T 1.5" as used in K-20 Mars Snooper
030310 BT-5CJ 3.00" as used in #0805 Mini BOMARC

So: the only existing tube at the time that would comport with the dimension in question was the 6.00" long 030303 BT-5, as used in the Mini Tri-Pak. But no white body tube (WBT) version was ever made at that time (perhaps ever) that I'm aware of, so unless the initial release of the Leprechaun was made with a special run of the 6" tube in a white cover, or unless the initial release was made with the brown kraft version (as per the Mini Tri-Pak), then we have to assume the Leprechaun always used the same 8" WBT-5 as the Gnome, as at some point it most certainly did (that's what my kit has), and that the listed dimension in the 1988 catalog is in fact an error.

The only way to be conclusive on the point is if someone out there actually has a version of the Leprechaun with a 6" tube in the kit. If so, it would be a one year wonder, and a rare kit.

__________________
John
YORF #003
SAM #004

John,

I really appreachiate all of the work you put into your body tube reference guide and that is why I linked to it.

I found it very helpful when I wanted to clone an Estes Ninja but did not know the length of the body tube a few years ago.

Thanks for your work.


Go Steelers!

I thank you both very much for your replies. The information given in the 1988 and 1989 Estes catalogs (and even in the instructions of the 10.25" [Gnome-length] Leprechaun), however, appear to support the 8.2" length for the 1988 Leprechaun. Here are four reasons why:

[1] The weights of the Gnome and the Leprechaun that were given in the 1988 Estes catalog (see: http://www.ninfinger.org/rockets/no...a/88est014.html ) were 0.42 ounces (Gnome) and 0.4 ounces (Leprechaun). In the 1989 Estes catalog (see: www.ninfinger.org/rockets/nostalgia/89est14.html ), the now-10.25" long (Gnome-length) Leprechaun's weight was given as 0.42 ounces, which was identical to the Gnome's weight.

[2] Even the 10.25" long Leprechaun came with a brown kraft paper body tube (I had thought it was white), because its instructions called for both white and yellow spray paint (see: http://plans.rocketshoppe.com/estes.../Leprechaun.pdf ), so the 8.2" long original Leprechaun kit must have come with a 6" brown kraft paper BT-5 body tube.

[3] From their side-by-side catalog illustrations, one can see that the Leprechaun is obviously considerably shorter than the Gnome (the Gnome has a greater fineness ratio [length/width ratio]). Also, the Leprechaun's plastic upper launch lug/shock cord anchor ring is located just behind the nose cone/body tube joint--and even then, the rest of the body tube behind the ring appears shorter than the length of the Gnome's body tube behind the Gnome's forward ring. The ring front edge-to-body tube front edge distance on the Leprechaun is the measurement that I need.

[4] If the Leprechaun had always been the same length as the Gnome, it could have used all of the same engines that the Gnome could (and can), but the Leprechaun's only recommended engines were the 1/2A3-4T and the A3-4T. Also:

(Just for completeness' sake, the other kit in the 1989 Estes catalog that used the Gnome's plastic fin unit, the Sprite [No. 0885, see: www.ninfinger.org/rockets/nostalgia/89est14.html ], used a 9" length of BT-5 according to John Brohm's body tube reference document. Having once had a Sprite, I know that its body tube was made of brown kraft paper. Also, John contributed a scan of the Sprite's decal sheet to "Ye Olde Rocket Plans" [see: www.oldrocketplans.com/decals/est0885_Sprite.jpg ].)

__________________
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.
NAR #54895 SR

It's not very often I have an answer for someone, but I happen to have an original unbuilt Leprechaun. It does indeed have a 6" BT-5 in the package.

Mike

Can you comment on whether the tube is white or brown?

__________________
John
YORF #003
SAM #004

Well the Leprechaun kit I have has a white body tube, same as the original Gnome. I interpreted the painting instructions to apply to the nose and fin can, as each is white in my kit.

As mentioned, based on the evidence to date, the only way to know for sure if the original Leprechaun was shorter is if in fact there's a short one out there. It seems there may be, and I'd love to see a photo. It would be a rare item.

__________________
John
YORF #003
SAM #004

Yes, I can confirm that. The 9" airframe in my Sprite kit is indeed made from brown kraft paper.

__________________
John
YORF #003
SAM #004

Mike;

One more thing if you wouldn't mind - what dimensions are printed on the face card? A scan of the card would be terrific.

__________________
John
YORF #003
SAM #004