Astrobee 350 fin dimensions?

[blackshire]

Hello All,

Last night I was looking at my two unbuilt Semroc "Retro-Repro" Centuri Astrobee 350 kits (see: www.rocketreviews.com/reviews/all/sem_astrobee_350.shtml ), and their fins just looked too small (compared to what I remembered from the old Centuri catalogs). This morning I looked through the old Centuri catalog scans on the Ninfinger Productions web site, and the fins on their Astrobee 350 kit (which they also called the "Aerobee-350" between about 1971 and 1975, during which years they added balsa strip conduits to the kit) were indeed *much* larger than the fins on the Semroc "Retro-Repro" Centuri Astrobee 350. Below are links to several images that show the larger fins.

(Also, before I get to those links below, I found that the Arcon-Hi's booster was also sold separately by Centuri for use with their Astrobee 350 and Payloader II kits, [see: www.ninfinger.org/rockets/catalogs/centuri65/65cen8.html ], so the Semroc Arcon-Hi booster could be used with Semroc's "Retro-Repro" Astrobee 350 and Payloader II kits to fly them as two-stage rockets.)

Do anyone here have the fin dimensions or a full-size fin pattern for the Centuri Astrobee 350/Aerobee-350 fins? I'd like to build my two Semroc Astrobee 350 kits with the correct-size fins. I would also share the fin dimensions or fin pattern with Semroc. Including these larger fins in the Astrobee 350 kits would eliminate the need for adding the metal washer weights to their nose cones (the EMRR flight logs reported "cartwheel" flights of the Semroc Astrobee 350, especially with heavier "C" motors.) Here are links to photos and drawings of the Astrobee 350/Aerobee 350 from the Centuri catalogs:

Centuri "Astrobee 350" (*without* balsa strip conduits)
www.ninfinger.org/rockets/catalogs/centuri65/65cen10.html
www.ninfinger.org/rockets/catalogs/centuri65/65cen20.html (in "Student Special" Starter Set)
www.ninfinger.org/rockets/catalogs/centuri67/67cen8.html
www.ninfinger.org/rockets/catalogs/centuri68/68cen8.html
www.ninfinger.org/rockets/nostalgia/69cenp18.html

Centuri "Aerobee-350" (with balsa strip conduits):
www.ninfinger.org/rockets/catalogs/centuri71d/71dcen26.html
www.ninfinger.org/rockets/nostalgia/72cen012.html
www.ninfinger.org/rockets/nostalgia/73cen022.html
www.ninfinger.org/rockets/catalogs/centuri74/74cen22.html

I hope this information will be helpful.

[ddavis1]

Hello, I had just finished building an Aerobee 350 and I too had this problem. I happened to find a drawing online done by G. Hary Stine showing the Astrobee 250 and 350. It did not give the specific fin size but it appears the width of the fin is 1 and 1/2 times the diameter of the body tube. Of course Centuri may not have used his drawing as a referance. I just scaled the fins up accordingly and it appears to be correct. I'm sure it will be more stable. I had an original Aerobee 350 and I can't see any differance from what I remember. I think that the Aerobee and Astrobee had the same fins but can't say for positive. I don't know if this helps but good luck in building your Astrobee's.

[Chas Russell]

I have a line drawing from Space General and the NARTS Scale Pak and the fin data agrees. Root edge against the motor is 50.0". Leading edge sweeps back 45 degrees. The trailing edge sweeps back 15 degrees. The tip length is 25". The individual fin span is 34.2". Root thickness is 5.7" and the tip thickness is 3.1"
Overall length from nose tip to the end of the nozzle is 473.62". Nose cone length 110.0". Diameter is 22.0". Payload section is 22.0".

Hope this helps.
Chas

[Chas Russell]

NARTS is the NAR's Technical Services offering scale data and other NAR products. www.nar.org

The NARTS Aerobee 350 pak includes a color photo of the 350 and another of the Nike booster.

Chas

[blackshire]

I thank you both very much for your replies! I have a copy of "Rockets of the World: A Modeler's Guide" by Peter Alway, which covers the Aerobee 350. Since the full-scale Aerobee 350's fins were considerably larger in relation to its body diameter, I think scaling up the Astrobee 350 fin pattern in the old NAR Astrobee 350 plans (see: http://www.oldrocketplans.com/narts/ASTROBEE-250-350_104.pdf ) from the 13/16" body tube diameter to the 1.040" body tube diameter of the Centuri and Semroc Astrobee 350/Aerobee 350 kits would yield the correct fin size and shape (it *looks* right when compared with the Centuri catalog Astrobee 350/Aerobee 350 kit illustrations, in any event).

[blackshire]

Another thing I just found--I compared the (under-sized) laser-cut fins in one of my two unbuilt Semroc "Retro-Repro" Centuri Astrobee 350 kits, and they are the same size and shape as the fin pattern in the old NAR Astrobee 250 & 350 plans, which specify the MMI 13/16" (0.8125") diameter body tubes (see: http://www.oldrocketplans.com/narts/ASTROBEE-250-350_104.pdf ).

The fins from the "Retro-Repro" Centuri Astrobee 350 kit could be used with the nose cone and a length of the body tube from the "Retro-Repro" MMI Aerobee-Hi kit to build a 0.8125" diameter Astrobee 350 or 250.

[Carl@Semroc]

James,
That is some detective work! It has taken a while to research this. Our Astrobee 350, in Peter Always words, is a " 1:1 scale model of a Centuri scale model of a non-existant rocket." Even though G. Harry drew the plans for an Astrobee-250 and Astrobee-350, Peter was unable to find anything that was ever produced that matched the plans. I think Centuri realized that as well, because between the 1969 catalog and 1971 catalog, they renamed it the Aerobee 350, but it was not even close to the actual Aerobee 350, which would have had the main body tube extended from 10.5" to 17.5" and increased the fin size even more. The conduits were added to make it closer.

When I did the Astrobee 350, my notes say I had a kit, but I cannot find it anywhere. The scan of the fins has been lost during a drive crash in 2003. I thought I had recovered all the archive data from it and the backup. I have a vector outline of the fin, but it looks too big (green outline below.) The current production fins are too small (dark blue outline.) The same scale ROTW Aerobee 350 fins (red outline) don't even look close. We are gling to change ours to match the light blue outline which is the correct scale for a 1.04" diameter to match Harry's drawing, which was probably the inspiration for Centuri.

Thanks again James for all your work tracking this down. I don't think we will release the same scale fins for a smaller tube since we would also have to release a new nose cone and tube and the confusion factor would be even greater.

We were considering a Deci-scale model of the Aerobee 350, but at 48" tall and BT-70 size, it would probably have a limited market.

[blackshire]

Thank you (and thank you for fixing the kits' fins), Carl! While there *were* Astrobee 200 and Astrobee 500 vehicles (see: http://www.astronautix.com/lvs/astrobee.htm ), Peter is right--no Astrobee 250 or 350 rockets were ever built. (That doesn't dampen my appreciation for the "Retro-Repro" Astrobee 350 kit in the slightest, though!) I think these never-built Astrobee vehicles were intended to use various versions of the 40" diameter Algol rocket motor (see: http://www.astronautix.com/stages/algol1.htm ), for the following reason:

The 13/16" (0.8125") diameter Astrobee 350 (and the shorter but otherwise identical Astrobee 250) "scale up" from G. Harry Stine's 1:49 scale drawing (see: http://www.oldrocketplans.com/narts/ASTROBEE-250-350_104.pdf ) to 39.8125" in diameter, which is just shy of 40 inches. (For reference, the largest of the Astrobee series which carried the Astrobee name [see below for an exception], the Astrobee 1500, was 31" in diameter. So were/are the various Super Chief sounding rockets [see: http://www.astronautix.com/lvs/supchief.htm ], which are also part of the Astrobee series. The 31" diameter motors were/are Sergeant or Sergeant-derived motors such as the Aerojet Junior, Castor I, and Castor II, which served/serve as second stage motors that were/are boosted by surplus Talos missile motors in the various versions of the Super Chief sounding rocket.)


-- Jason

[jdbectec]

James,
That is some detective work! It has taken a while to research this. Our Astrobee 350, in Peter Always words, is a " 1:1 scale model of a Centuri scale model of a non-existant rocket." Even though G. Harry drew the plans for an Astrobee-250 and Astrobee-350, Peter was unable to find anything that was ever produced that matched the plans. I think Centuri realized that as well, because between the 1969 catalog and 1971 catalog, they renamed it the Aerobee 350, but it was not even close to the actual Aerobee 350, which would have had the main body tube extended from 10.5" to 17.5" and increased the fin size even more. The conduits were added to make it closer.

When I did the Astrobee 350, my notes say I had a kit, but I cannot find it anywhere. The scan of the fins has been lost during a drive crash in 2003. I thought I had recovered all the archive data from it and the backup. I have a vector outline of the fin, but it looks too big (green outline below.) The current production fins are too small (dark blue outline.) The same scale ROTW Aerobee 350 fins (red outline) don't even look close. We are gling to change ours to match the light blue outline which is the correct scale for a 1.04" diameter to match Harry's drawing, which was probably the inspiration for Centuri.

Thanks again James for all your work tracking this down. I don't think we will release the same scale fins for a smaller tube since we would also have to release a new nose cone and tube and the confusion factor would be even greater.

We were considering a Deci-scale model of the Aerobee 350, but at 48" tall and BT-70 size, it would probably have a limited market.

I've got a built Centuri Aerobee 350 in the attic, in storage, I'll rummage around and trace the fin pattern and post it as soon as figure out how.

[jdbectec]

Here is a scan, and the measurments, as best as I could get them, this would be the final Aerobee 350 with the plastic cone.

And by the way the conduits were spruce or bass, not balsa. 1/8"x1/32?"x61/4", Bt length:10 1/2", Nose cone 5:1 ogive.

[Carl@Semroc]

Here is a scan, and the measurments, as best as I could get them, this would be the final Aerobee 350 with the plastic cone.
Thanks Jeffrey!

That is the one I am going with. It is slighly smaller than the one upscaled from Harry's plans, with slighly different angles. It is nothing close to the later full size Aerobee 350. Even though they added the conduits, they most likely kept the fins shape and size from the original Astrobee 350 kit.

[jdbectec]

Thanks Jeffrey!

That is the one I am going with. It is slighly smaller than the one upscaled from Harry's plans, with slighly different angles. It is nothing close to the later full size Aerobee 350. Even though they added the conduits, they most likely kept the fins shape and size from the original Astrobee 350 kit.

You're welcome. Please keep in mind that they were cut from a printed sheet by a twelve year old! :) They are traced off my model, and each side is a different fin. IIRC the lines were about they width of what you'd draw with a sharpie, definately room for error. I'm not sure if I stacked and sanded them, It was about 40 yrs. ago! :eek:

I agree that the fins are the same as the Astrobee 350.

Of course, the pdf should be printed actual size.

[blackshire]

Here is a scan, and the measurments, as best as I could get them, this would be the final Aerobee 350 with the plastic cone.

And by the way the conduits were spruce or bass, not balsa. 1/8"x1/32?"x61/4", Bt length:10 1/2", Nose cone 5:1 ogive.Jeffrey, I thank you very much for taking the time to retrieve and measure your Astrobee 350! I have sent a copy of your conduit description & measurements and a link to your fin dimensioned drawings to Carl. [ADDENDUM--I didn't see that Carl already saw your posting this morning! I feel like the "running-down-the-hallway" government employee in Washington in the movie version of Tom Wolfe's "The Right Stuff." :-) ]


-- Jason

[ddavis1]

I have an idea that may appeal to a few people. Perhaps Carl at Semroc would like to make his Astrobee kit into a dual kit, offering ether the Astrobee or Aerobee option for the build. I bought his Astrobee kit specifically for the purpose of converting it to the Aerobee 350 that I had built so long ago. The kit turned out very well. I may even buy another in the future since it was one of my favorite models. Just a thought.

[Green Dragon]

Don't have the model right handy to trace fins or compare to the ones posted, but here is a photo of my original , 1960s version, still can read the 'root edge' printing on the fins..... not sure how close they're cut to the lines.

~ AL

[blackshire]

I have an idea that may appeal to a few people. Perhaps Carl at Semroc would like to make his Astrobee kit into a dual kit, offering ether the Astrobee or Aerobee option for the build. I bought his Astrobee kit specifically for the purpose of converting it to the Aerobee 350 that I had built so long ago. The kit turned out very well. I may even buy another in the future since it was one of my favorite models. Just a thought.That's an interesting idea. Since the later "Aerobee-350" version appeared to have no decals (the color separations being achieved by masking during painting), the only new parts that would be needed for such a "customizable kit" would be the spruce or basswood conduits.

[blackshire]

Don't have the model right handy to trace fins or compare to the ones posted, but here is a photo of my original , 1960s version, still can read the 'root edge' printing on the fins..... not sure how close they're cut to the lines.

~ ALThe upper corners of the fins look a bit "curvy," but since they all look that way I imagine that was an intentional "bench modification." Also, the Astrobee 350 can be used with the booster from the Arcon-Hi to fly it as a two-stage rocket. In the 1967 Centuri catalog, they offered the Arcon-Hi booster separately for use with the Astrobee 350 and the Payloader II.

[jdbectec]

Jeffrey, I thank you very much for taking the time to retrieve and measure your Astrobee 350! I have sent a copy of your conduit description & measurements and a link to your fin dimensioned drawings to Carl. [ADDENDUM--I didn't see that Carl already saw your posting this morning! I feel like the "running-down-the-hallway" government employee in Washington in the movie version of Tom Wolfe's "The Right Stuff." :-) ]


-- Jason
Sorry, I don't remember that scene, must be time to watch the movie again! I'm glad I was of some help to you and Carl.

I think the idea of a dual kit is good. If I'm not mistaken there was an "Aerobee like" kit in the stellar line that used the same conduits, but, the name escapes me now. I know it was discussed recently.

A trace of the earlier version would be helpful, my fins were slightly rounded on the tips too, I think from airfoiling. I extended the lines to a proper corner before I scanned them.

I'm 60% sure the fins still had Astrobee 350 printed on the sheet. I remember being confused "back in the day" about the similarities in the models. My goal at the time was to build only scale and sci-fi models, and to obtain all of them that were available...........Come to think of it, It still is!

[blackshire]

Sorry, I don't remember that scene, must be time to watch the movie again! I'm glad I was of some help to you and Carl.He was a member of some federal agency (I forget which) who thought he had fresh news of the early Soviet space spectaculars. Every time he ran down the hallway to inform his superiors of the latest Soviet achievement, he would find them already watching TV coverage of it.I think the idea of a dual kit is good. If I'm not mistaken there was an "Aerobee like" kit in the stellar line that used the same conduits, but, the name escapes me now. I know it was discussed recently.That was the Stellar Lancer (see: http://www.ninfinger.org/rockets/catalogs/centuri75rt/75rt8.html , on the right-hand page). This same rocket--without conduits--was called the X-7, and it was part of Centuri's "Power System Outfit" (see: http://www.ninfinger.org/rockets/catalogs/centuri_pshandbook/cenpshandbook.html and http://www.ninfinger.org/rockets/nostalgia/79cen008.html ). The X-7 also came with the Stellar Lance Corporal booster. Semroc has the parts (including laser-cut fins) for the Lancer/X-7 (and the Lance Corporal booster) and the large X-16 cluster motor mount/single motor mount "switchable" rocket from the Power System Outfit.A trace of the earlier version would be helpful, my fins were slightly rounded on the tips too, I think from airfoiling. I extended the lines to a proper corner before I scanned them.Good. In the catalog photographs, the fin edges were all straight.I'm 60% sure the fins still had Astrobee 350 printed on the sheet. I remember being confused "back in the day" about the similarities in the models.I wouldn't be surprised--changing the name on the pre-printed fin sheet would have cost money, and a lot of modelers wouldn't have noticed the change anyway. Did your Aerobee 350 come with decals? Unlike with the earlier ("conduit-less") Astrobee 350, the catalog photographs and illustrations of the later Aerobee 350 give me the impression that its differently-colored sections were achieved solely through masking during painting.My goal at the time was to build only scale and sci-fi models, and to obtain all of them that were available...........Come to think of it, It still is!I used to be that way until I contracted "accuracy fever"--if I couldn't build a scale model to be within a hair of perfect, I didn't do it at all...which resulted in my building very few of them. :-) Now I can enjoy Sport Scale, Semi-Scale, and even Scale-like model rockets--like an impressionist painting, a good scale model need not be correct down to exact-scale corrugations in order to look good and be enjoyable to fly.

[jdbectec]

[That was the Stellar Lancer (see: http://www.ninfinger.org/rockets/catalogs/centuri75rt/75rt8.html , on the right-hand page). This same rocket--without conduits--was called the X-7, and it was part of Centuri's "Power System Outfit" (quote)

Yep that's the one, ithink someone measured the proper thickness of the conduits

.Good. In the catalog photographs, the fin edges were all straight.I wouldn't be surprised--changing the name on the pre-printed fin sheet would have cost money, and a lot of modelers wouldn't have noticed the change anyway. Did your Aerobee 350 come with decals? Unlike with the earlier ("conduit-less") Astrobee 350, the catalog photographs and illustrations of the later Aerobee 350 give me the impression that its differently-colored sections were achieved solely through masking during painting(quote)

No decals, the paint job was poorly masked and brush painted, It is well below my standards even at the time. I must not have had the money to buy the proper supplies. I was finicky even then.

I used to be that way until I contracted "accuracy fever"--if I couldn't build a scale model to be within a hair of perfect, I didn't do it at all...which resulted in my building very few of them. :-) Now I can enjoy Sport Scale, Semi-Scale, and even Scale-like model rockets--like an impressionist painting, a good scale model need not be correct down to exact-scale corrugations in order to look good and be enjoyable to fly.[/QUOTE]


I well understand this, now!