# Black Brink I Scale

Discussion in 'Scale' started by CharlaineC, Aug 27, 2010.

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1. Aug 27, 2010

### CharlaineC

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So i have 2 18" bt55's and a black brant II style nose cone and decided that i wanted to build the black brant I before i built the black brant II i have coming. My question is scaling am i doing this right as this is my first scale model not from a kit. Hear is the raw data
Dimensions
Length: 24 ft, 4 in (7.42 m)
Diameter: 17.2 in (43.5 cm)
Weight: 2493 lb (1130 kg)
Thrust: 25,000 lb (110,000 N)
Duration: 20 sec
Impulse: 375,000 lb-s (1,679,000 N-s)
Payload: 240 lb (109 kg)
Ceiling: 50 mi (80 km)

My scaled down version bt55 based on this site http://www.postwarv2.com/BBI/
bt55 20.4" long

here is my rocksim. any help would be loved thank you

View attachment blackbrintI.rkt

Last edited: Aug 30, 2010
2. Aug 27, 2010

### Marlin523

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Posting here to easily follow the thread.

3. Aug 30, 2010

### ghrocketman

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Charlaine,
What is a Black Brink or Brint ?
Are you referring to a Black BRANT or is this some rocket I've never heard of ?

4. Aug 30, 2010

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If your body tube is 1.325" then the multiplier would be approx 0.0770 so your rocket overall height would be about 22.484".

I divided the diameter of the model rocket (1.325") by the diameter of the real rocket (17.2") which equal .0770. then I use that number as the multiplier for the other measurements.

It is a Black Brant I, II, etc.

good luck

5. Aug 30, 2010

### CharlaineC

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im looking to make a bt55 version of the black brant I its a 3fnc basic design

6. Aug 31, 2010

### MarkII

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The CARDEPLEX-fueled Black Brant I (Propulsion Test Vehicle) was rare! It was a prototype, and only 17 of them were launched. I don't think that there are many photos available. Great find, and great project! The Black Brant I supposedly had a shorter nose cone than the well-known BBII.

7. Sep 9, 2010

### GuySmith

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Hi Charlaine,

Sorry I took so long to post. It took a while to dig out the file I had on the Black Brant I. The performance report that I found covers Black Brant I 01 through 07. Attached is the scale sheet I derived from that report. I also included a copy of the coverpage. The entire report is 290 pages and is 43MB in size.

Enjoy!

Guy

8. Sep 10, 2010

### CharlaineC

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Thank you now i need to fins a boat tail that will suit her. i think the nose cone i have will work if i understand right their the same size from anyway. but i didnt realize it had a boat tail i thought it was a basic 3fnc and i was close on the fins i see thats cool. thank you so much

9. Sep 10, 2010

### GuySmith

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Charlaine,

I would just model the tailcone as a paper transition between a BT55 and a BT50. That would be close enough to reflect scale. The way these rockets were designed, they were intended to be modular allowing variations in tail section and payload/nose section. It would not be a reach to place a Black Brant II payload/nose section on a Black Brant I as a proposed variant. I have yet to determine which specific round of the Black Brant I used the large telemetry antenna vs the small telemetry antenna, records are sparse to non-existant, use whatever suits your fancy.

Guy

10. Sep 10, 2010

### hutch

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CharlaineC - This looks like it would be a great model! I have not seen much information about the BB I before - thanks for the link

I've built a number of BB IV's in the past - GuySmith - Would it be too much trouble for you to send me the whole report?

Are there any indications of color patterns in the report or anywhere on the web?

11. Sep 10, 2010

### GuySmith

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Hutch,

All the report has are a fair number of BW photos and LOTS of flight performance data. No references as to colors and I have not found any color photos in any archives. I don't have a problem sending the file but it is rather large and exceeds many e-mail attachment limits, I would most likely have to break it up into pieces to e-mail. PM me with details (e-mail and size-limits) and I will send it. I did not bookmark the website I got it from and it is now long gone from the web.

Guy

Last edited: Sep 10, 2010
12. Sep 12, 2010

### MarkII

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That's right about the nose cone; GuySmith's attachment verifies it. On the Black Brant I and II, the cylindrical section aft of the conical nose, where the antennae were attached, was part of the "nose cone." In the Black Brant I, this section was shorter than it was on the BB II. The conical nose section was the same length in both rockets, so you can use a Black Brant II n.c. for it. You've picked a very unusual subject for a scale project!

13. Sep 13, 2010

### CharlaineC

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thanks i even found my bt 55 plastic boattail will cut it down so it can fit the 24mm mount then fill the four fin slots by using an outer wrap. because i want this bird to fly on both 18mm and 24mm motors.
how many antenna did it have i will be using copper wire i think unless i can get some piano wire.

14. Sep 13, 2010

### GuySmith

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Charlaine,

Three, one in line with each fin.

Guy

15. Sep 13, 2010

### GuySmith

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MarkII,

The BB II reports I have (rounds 17-22,29,30) show a conic section 86 inches long (this includes a 2-1/2 inch spike) and a payload section 24.56 inches long versus the BB I with a conic section of 60 inches and a payload section of 21.92 inches.

Guy

16. Sep 13, 2010

### MarkII

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Oops, you're right. I misread the dimensions in your attachment. The diagram of the Black Brant II in ROTW also shows a length of 86". But neither that source nor George Flynn's scale article in the 12/71 ModRoc show any spike, though. Sorry, Charlaine, it looks like you will need a different nose cone after all.

17. Sep 13, 2010

### GuySmith

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MarkII,

You are right also! Rounds 19-22 show no spike, but the point starts at sta 0.5 not 0.0 making the cone 85.5 inches rather than 86 inches. The spike is present on rounds 17,18,29 and 30. Rounds 17 and 18 were four fins of a different profile than the oft seen round 16. Rounds 19 through 22 appear to be clones of round 16. Rounds 29 and 30 have a modifed three fin profile with a staight tail section rather than a conic tailcone.

Guy

18. Sep 13, 2010

### CharlaineC

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oh ok what is do you think i should do what are you thinking the size of the nose should be a few inched shorter?

19. Sep 13, 2010

### MarkII

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Can you point me to some data that shows what you are talking about? The only Black Brant II scale data that I have ever seen was from the two well-known sources that I mentioned. That is the data set that I was working from. I'm interested in this because I'm getting ready to start a BB II project soon myself.

Last edited: Sep 13, 2010
20. Sep 13, 2010

### GuySmith

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MarkII,

I found a website that hosted a number of Black Brant reports and data booklets that had been declassified. I failed to bookmark that site and can no longer find it. I did download the Black Brant I report mentioned here and three Black Brant II reports because they had dimensional data, one report documented 17 and 18, one documented 19 through 22 and one documented 29 and 30. There were others but as I said those did not have dimensioned drawings. There were others in the list showing as pending upload, but only had titles marking their existence. 17,18 is 6MB and 126 pages. 19-22 is 336KB and 24 pages. 29, 30 is 4.8MB and 80 pages. The Black Brant I document is much larger but the detail is amazing.

Guy

21. Sep 13, 2010

### GuySmith

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Charlaine,

I would use the BB II style nosecone adding 16*0.077 or 1.23 inches to the length of the rocket to maintain scale. This would then be a hybrid Black Brant I booster with a Black Brant II style nosecone.

Have fun!

Guy

22. Sep 13, 2010

### Massrokit

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Iwas wondering if you can sent me (e-mail) your copy of the report?

23. Sep 16, 2010

### GuySmith

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Update: I finally found some information on color for the Black Brant I pictured in Charlaine's link:

Nosecone: Black
Logo at top of Motor Case: Black
Top portion of Motor Case: White
Bottom portion of Motor Case: Red
Tailcone: Black
Fins: Black

(source- www.sigmarockets.com via wayback machine)

24. Feb 15, 2011

### bobby_hamill

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Guys

This link might be help full to you about the Black Brant ! . It has launch dates and everything. the original name for the Black Brant 1 was the "Snow Goose"

http://www.astronautix.com/fam/blabrant.htm

I have several original publications on the Black Brant rounds with pre flight data and drawings. Let me dig them out and scan some of them

Here is a photo of my scratch built 4 Inch diameter Black Brant 2b that I achieved my TRA cert 2 with.

Bobby H

25. Feb 15, 2011

### sandman

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Was that at Whitaker, NC?

26. Feb 15, 2011

### bobby_hamill

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Hay sandman long time no see/chat !! how have you been ???

Yep that is Whitakers NC my nickname there was "bird dog" lol

Bobby H

27. Feb 15, 2011

### sandman

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LOL! I thought that was you.

I've been...busy.:wink:

28. Feb 16, 2011

### bobby_hamill

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Here are some original Black Brant photos to help you with your project

Bobby H

29. Feb 16, 2011

### bobby_hamill

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guy

here are some of my black brant 2 construction photos

4 and 6 are photos to my payload section for my scratch built 4 inch diameter BB2 with 4 fins. I had the battery s on the back so if the nose cone came in ballistic the moving battery s would not strip off the electronics from the circuit board . I used 2 missile works extremes and a magnetic apogee detector ( MAD )

Photos 12 and 13 show the fiberglass mold and the first nosecone made with it A 6 inch diameter BB2 conical

Bobby H

30. Apr 21, 2011

### bobby_hamill

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Guy

care to share any of the Black Brant reports you downloaded ?

Bobby Hamill

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