AHH! I spent 30 minutes writing the first reply to this, but the file I attached was to big and I accidentally got brought back to a blank page. Grrrr. I hate it when that happens...and the 2nd time is never as good as the first. Oh well. So again.....
Yeah, it would be nice to have some heavier lifting and larger size BP motors...there were some in the past. As many have said the most well known big and heavly lifting BP motors were the notorious FSI E60's and F100's. These were coreburning (therefore very fast) cardboard cased BP motors. An even more unreliable past big BP motor was the E15. All of these motors (especially the E15) tended to be very unreliable and they are all now OOP....FSI is out of business. It seems that BP motors begin having problems in large 24mm up sizes. As Neil mentioned, the grains were very sensitive and a hairline crack in the propellant would cause problems, and also many other problems have plagued BP motors...I don't know specifically what all these are but some of them I think have to do with the continued use of the rolled cardboard case, and coreburning BP motors (like the E60 and F100) can easily overpressurize due to the speed BP burns at, and a coreburning motor increases the surface area tremendously, therefore increasing combustion speed, and then often resulting in the motor CATOing as it can't contain itself. So in general, BP just isn't well suited for larger motors b/c of the many reliability factors that must be considered. However, Rocketflite used to have their "Silver Streak" line of large BP motors in sizes from E to H. Although they had their problems, these motors were much more reliable and much cooler. #1, they had cardboard wrapped T-6 aluminum cases...this greatly increased case strength, allowing the motors to better withstand the great force of the quick burning BP (especially because these were also coreburning). #2 these motors had a much better record and were simply more reliale...probably because they had the aluminum case, were fabricated better, and had other much more reliable qualities than motors like FSI and the old Estes E. #3, these motors used "modified" blackpowder....and the only "modification" I can think of was the addition of titanium pieces to the propellant. There may have been some more additives to "tone down" and make the BP more suitable for the motors, but I'm not sure. Whether there were any other additives, it doesn't really matter...the addition of the titanium created a stunning special effect. The glowing and burning Ti chunks were shot out of the motor as it burned, creating a 25ft. long brilliant white flame, white smoke, and a brilliant shower of Ti sparks. This was definately the high point of these motors! These motors were coreburning as well, and to compensate for the common overpressurization of coreburning BP motors, the manufacturer reccomended that the igniter was installed at the bottom of the motor, allowing less propellant to ignite at once, reducing the chance of overpressurization. All of these things combined made for some pretty reliable BP motors....and they were visually pleasing as well. They had their problems, but beat out FSI and the Estes E15 by a lot...plus, when they CATOed it wasn't so bad because they created a huge plume of fire and sparks when they did. Unfortunately they, too are currently OOP, but the manufacturer says that he plans to bring them back someday. Rocketflite (
www.rocketflite.com), the manufacturer of these motors also produces the famous "Magnelite" igniter kits. The Silver Streaks most common designations were the 24mm E60SS, the 29mm F104SS, the 38mm G160SS, and the 38mm H330SS. There were other designations in the past (the F104SS and H330SS' were both incorrectly marked as F50SS and H220SS for a long time), and the E60SS may have not been produced (can't remember), but it's planned to be produced for sure if the motors ever return (it, with some of the other motors are listed as "N/A" on Rocketflites order form). They also came in regular delay times as well as a "-0" delay time for direct staging. I really hope these motors come back! Never got to use one, but they're really cool. Some links to some pics are attached below...I hope that helped!
www.rocketflite.com
https://tjm.home.texas.net/PC310007.JPG
https://straylight.dhs.org/rocket/images/rap/streak.jpg
https://ourworld.compuserve.com/homepages/CGibke/sstreak.jpg
https://www.liars.org/Ambassador/rk1.gif
https://ourworld.compuserve.com/homepages/CGibke/onyx.jpg
What was just one D12-0 pushing up 3 stages has now evolved to a (3)D12-0 cluster pushing 5 stages.Well,that is the first stage anyways... In essence it goes > (3)D12-0's, D12-0, D12-0, D12-0, C6-7.The first stage 3 motor booster has a reducer(2.5 dia.-29mm) that manifolds the ejection flames toward the nozzle of the next stage. I've launched it 6 times now and all everyone mostly says is,"Where did it go"? Fortunately I got all the boosters and sustainer back every time. Just lucky I guess.....Hopefully I'll be able to post some pics of the launch real soon....Thanks again
