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  #71  
Old 09-28-2011, 09:48 PM
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I'm with SEL....but would be most interested in motors that can't be had from the big E....these "hybrids" sound really interesting.
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  #72  
Old 10-05-2011, 12:31 PM
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Quote:
Originally Posted by Carl@Semroc
There are some new items on the Engine Survey page. Qualification testing on the Hybrid Port engines is complete and posted. Results for the 1/2A4, A7, 3/4B7, B7, 3/4C6, and C6 are given in a drawing and .eng files....The hybrid port has a slightly deeper drill than standard to get the 18N peak....Now we have to decide whether to release the standard 11N peak as well as the hybrids or just release the hybrids and avoid the confusion...Feedback and comments are welcome!
I ran a quick sim of the B7 as the first stage booster in an Astron Farside, and it looks to be sufficient, at about 43fps on a 3' rod. Even the A7 should work, at 39fps, staging at 18'! A B7-A7-1/2A4 combo puts it at 580', staging at 64 & 141 ft. Here's a vote for the hybrids, so we can fly our small 3 stagers again!
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  #73  
Old 10-05-2011, 02:54 PM
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Quote:
Originally Posted by PaulK
I ran a quick sim of the B7 as the first stage booster in an Astron Farside, and it looks to be sufficient, at about 43fps on a 3' rod. Even the A7 should work, at 39fps, staging at 18'! A B7-A7-1/2A4 combo puts it at 580', staging at 64 & 141 ft. Here's a vote for the hybrids, so we can fly our small 3 stagers again!
This sounds like fun BTW, I suggest swapping the A7-0 into the first stage and putting the B7-0 in the second. What are the staging altitudes for that?

Doug

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  #74  
Old 04-15-2012, 01:24 PM
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Default 29mm engines

I am still working on the Ex numbers and decided to put the 29mm back in. It turns out our current machine will make 29mm engines up to 3.25" long. It will take a totally new machine to go over 3.25" (bummer!)

I had missed the fact that Centuri bought the Coaster engine machine that made 1.0625" (27mm) x 8" long engines and sold them for a short while and then changed over to 1.125" (29mm) x 7.75" and 4.75". There was quite an evolution over a few year period.

1963
1.062" x 8" F11-3 49N-sec It and 54 sec Isp (low grade BP) same as Coaster 20lb

1964 1965 1966
1.062" x 8" F11-3 49 N-sec It and 54 sec Isp (still low grade BP ) called Hercules
1.062" x 5" E3.3-2 29 N-sec It and still low Isp called Atlas

1967
1.125" x 7.75" F14-4 37 N-sec It and 65 sec Isp ( higher grade BP) now called MINI-MAX 'PB'
1.125" x 4.75" E3.5-4 25 N-sec and 64 sec Isp now called MINI-MAX 'PB'

1969
1.125" x 7.75" F94-4 52.5 N-sec It and 85 sec Isp (highest grade BP) (metric labelling)
1.125" x 4.75" E7-4 25 N-sec and 54 sec Isp (large throat)

1971
1.125" x 7.75" F16-4 57.8 N-sec It and 94 sec Isp (highest grade BP) End burning
1.125" x 4.75" E15-4 39.6 N-sec and 83 sec Isp

1972
replaced by Enerjets, new case sizes are 1.125" x 3" and 5"

The LT-110 was the engine tube for the early Coaster engines and was replaced by the LT-115 for the 29mm engines and Enerjets.

The new engine survey shows some decision points. The 3/4E21 at 26 N-sec is the largest with 30.0 g or less of propellant. So all the 29mm engines in the 2.75" long casing would be able to be mailed via USPS ground with no additional charges. The full E20 at 3.25" and the 3/4F19 would have to be shipped with HAZMAT. The 3/4F19 at 62.5 g of propellant would be the largest we would ever make. The BATFE discussions we have had made us decide to never go more than 62.5g. We would have to sell them to certified users only, HAZMAT fees, and track each engine from cradle to grave. As long as we keep each engine under 62.5 g, we only track them until they are produced. Once they are packed in the casings, the BATF has no further interest in the BP or the engines.

Let us know what you think about the 29mm engines.
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  #75  
Old 04-15-2012, 01:45 PM
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Quote:
Originally Posted by Carl@Semroc

Let us know what you think about the 29mm engines.



They sound like a lot of fun. I will definitely try several of them in my SLS Brighton and be standing by for more kits from Semroc to use them in.
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  #76  
Old 04-16-2012, 12:04 AM
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The 29mm motors sound good, Carl.

Make some up and I will place an order.
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  #77  
Old 04-16-2012, 09:34 AM
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Quote:
Originally Posted by Carl@Semroc
Let us know what you think about the 29mm engines.
You have to ask us if we want to buy 29mm BP motors?

The E21 (-0) sounds perfect for one of my stagers that turned out to be too much for the lone D12-0 in the booster. So, yeah, bring 'em on!!

[Edit: I'll build a new booster just for that motor.]

Doug

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  #78  
Old 04-16-2012, 09:59 AM
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The 29mm motors sound great.
They don't sound like those wimpy-thrust "coming soon FOREVER" Thunderjets that I'm convinced have become vaporware after showing at trade shows....

Make sure you can do tham at a reasonable price point....

Any idea WHEN we are going to be able to get our paws on ANY Semroc engines ????
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  #79  
Old 04-16-2012, 01:14 PM
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Quote:
Originally Posted by ghrocketman
...Any idea WHEN we are going to be able to get our paws on ANY Semroc engines ????
There are not enough hours in a day and it seems like there are fewer all the time. We have to take in outside work to help pay the bills and still have to release a new kit each month. Having to invest over 200 hours to release a kit that will gross about $5,000 over its life means it takes most of our time to just stay even. If we could take a few months to work full time on engines, we would have them, but we would be out of business in the process.

Since the projected annual sales figures from the Engine Survey are only about $17K from SAM's, we can't afford to spend the time on engines that we would like to. We work on them when we get free time, but it is rare right now. We hope when the economy gets better, we will be able to burn off some inventory to help finance engines.
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  #80  
Old 04-16-2012, 02:10 PM
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Carl,
Totally understand.
You being gracious enough to give us an explanation is more than any other company ever cares to do.
Just another reason Semroc is #1 with ZERO close competition in my book. You and your entire team DO IT RIGHT !!!

I offer to 'beta test' any engines you find needing it !
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, if you have to ask, you probably aren't
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