Estes B8-5

[El Cheapo]

Does anyone know how old this motor might be or whenabouts Estes quit producing them?

 

[Micromeister]

What's the date code on the motor your looking at?
Not that it matters much, I fly 30 and 40 year old motor often, they are just as good or better then motors manufactured yesterday. As long as they haven't been heatcycled that is.
I'm afraid you'll not be able to fly it at a sanctioned NAR launch as they are no longer on the certified motors list but could be flown as part of the OOP motor program if you have one running

 

[El Cheapo]

I don't have them. I Ran into someone that wants to sell them. I figured someone on here would know the "end" date of production. That way I'd know somewhat the age.

 

[shreadvector]

End date of production: Review online catalogs.

If the catalogs list them, they were still in prodcution that year.

If the catalogs do not list them, they were out of production that year.

 

[El Cheapo]

That's the one thing I didn't ask was how and where they were stored. I have some "cobra" labled motors that I fly all the time with never a mishap.

In looking at some old catalogues online, it appears they were produced atleast 1985 to 1996. I didn't go back any further than 1985. Thanks for the catalogue tip. I didn't think of looking them up on Ninefinger Productions site.

 

[El Cheapo]

Well, I talked to the seller. Most are from 1990 - 1991 and were stored in ammo boxes in his garage in San Diego. Not too much of a temperature change as long as they stayed dry. The packaging looks to be in good shape according to the pictures he sent.

 

[El Cheapo]

So, was the B8-5 a decent motor?

 

[powderburner]

I'm surprised our TRF historians have not jumped in here to answer this one. Perhaps my post will contain enough mis-information to wake one of them up.

Yes, it was a pretty good motor.

Now, I have slept since then, and all that, but IIRC this was the re-labeled "metric" version of the famous old B14. I have not called Estes to confirm this, I'm just trying to remember.

I would still only use old motors like this in "expendable" rockets. By that I mean don't try to launch your favorite baby, the one you spent 376 hours assembling and painting. No offense to your friend, but if the motors were not in your immediate possession and care from the time they left the store shelf, you really don't know how they were taken care of. And that assumes they were handled correctly on the way to the store shelf.

Were/are they good motors? Heck, when it comes right down to it, ANY motor that goes WHHHOOOOOOSSSSHHHH-pop has got to be a "good" one.

 

[Bazookadale]

Now, I have slept since then, and all that, but IIRC this was the re-labeled "metric" version of the famous old B14. I have not called Estes to confirm this, I'm just trying to remember.

The B14 and the B8 are NOT the same motor. B14 was the metric version of the old B3 in the English system. Original B14 had the core drilled out, this was an expensive and dangerous job. To simplify manufacture they changed to a formed core which was not as deep, which gave lower peak thrust (5lb vs 7 lb) and a longer burn time . the result was the B8

 

[gdjsky01]

Extremely old resurrection of a thread.
But does anyone have a thrust curve of B8?
I see they were, way back when NAR certified, tho never CSFM approv
ed.
Nonetheless, if someone has a photo of a curve so I could make a rough ROCSIM file...

 

[dpower]

Here is RASP data for the B8, from an old version of pRASP:

; Estes B8 RASP.ENG file made from NAR published data
; File produced October 3, 2000
; The total impulse, peak thrust, average thrust and burn time are
; the same as the averaged static test data on the NAR web site in
; the certification file. The curve drawn with these data points is as
; close to the certification curve as can be with such a limited
; number of points (32) allowed with wRASP up to v1.6.
B8 18 70 5 .0055 .0174 E
0.031 2.437
0.068 6.662
0.102 11.212
0.142 17.062
0.187 22.800
0.196 20.640
0.212 17.871
0.227 15.434
0.239 12.996
0.249 10.071
0.259 7.149
0.277 6.337
0.306 5.850
0.351 5.362
0.391 5.037
0.419 5.362
0.436 4.550
0.464 2.437
0.500 0.000

 

[jsdemar]

B8-5 total_impulse=5.00N-sec, Peak=22.2N, burntime=0.60 sec, initial weight=19.3g, prop weight=6.24g



Edit: using the Estes mass values, correct ENG first line should be:
B8 18 70 5 0.00624 0.0193 E

 

[Zeus-cat]

I got two from my wife's old boss and flew them back in 2011. They worked fine for me.

The second B8-5 was used in a scratch built, very light rocket. Here are the results from the Altimeter Two that was inside. The descent data is not shown as the shock cord broke. All parts of the rocket were recovered.

Apogee 399 feet
Top Speed (mph) 119
Burn Time (sec) 0.6
Peak Accel 23.0
Avg. Accel 9.5
Coast to Apogee (sec) 4.2
Apogee to Eject (sec) -0.2
Ejection Altitude 374 feet

Same rocket on the same day using a B4-4
Apogee 397 feet
Top Speed (mph) 110
Burn Time (sec) 1.1
Peak Accel 14.9
Avg. Accel 4.7
Coast to Apogee (sec) 3.5
Apogee to Eject (sec) 0.0
Ejection Altitude 397
Descent Speed (mph) 11
Flight Duration (sec) 27.8
Descent Speed (fps) 16.1

 

[BEC]

Here's a .pdf of the cert data as it was once posted on the NAR web site. I don't recall how I came by this file, but....


I got a number of B8-5s from someone getting out of rockets a few years ago and still have a few. They sure make a light model scoot off the pad. They're not B14s, but they are definitely not B4s or B6s either.

View attachment B8.pdf

 

[dpower]

Here's a .pdf of the cert data as it was once posted on the NAR web site. I don't recall how I came by this file, but....

That explains where my RASP data came from. I'll put this in Rocksim and do some comparisons just for kicks.

 

[gdjsky01]

If I forgot to say thanks, thanks!

 

[RoyAtl]

The B14 and the B8 are NOT the same motor. B14 was the metric version of the old B3 in the English system. Original B14 had the core drilled out, this was an expensive and dangerous job. To simplify manufacture they changed to a formed core which was not as deep, which gave lower peak thrust (5lb vs 7 lb) and a longer burn time . the result was the B8

Correct, but over the years, the later B14 was still called a B14 even though it was a B8. This went on for quite a few years until they actually relabeled it B8.