tag:blogger.com,1999:blog-1644326416987696055.post1346269751052370388..comments2023-06-30T05:07:50.781-07:00Comments on A Continuous Upward Climb: Announcing High-5DTH Rockethttp://www.blogger.com/profile/09222212036229618785noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-1644326416987696055.post-19981884050911204832008-10-25T12:11:00.000-07:002008-10-25T12:11:00.000-07:003 G motors? My first reaction was "Naw, this is wa...3 G motors? My first reaction was "Naw, this is way too heavy for that." But further thinking has lead me to believe it might be a good idea for it's first flight.<BR/><BR/>Original estimates were that this would be 8 pounds with engines loaded and payloads installed. If I were to put 3 G80's in it, that would be a combined average impulse of 240 Newtons, divided by 4.45 is 53.93 pounds. I've heard a good rule of thumb is a 5:1 thrust-to-weight ratio, so 53.93 lbs / 5 would equal 10.78 lbs. That's more than this rocket would ever weigh, especially with only G motors installed.<BR/><BR/>Then I went into RockSim and loaded it 3 G80 motors (this is the old kind I think) and it managed to pull off 1,300 feet!<BR/><BR/>The only thing is that you can't get certified on multiple SU G motors, I need to use a full-fledged H or I motor, since I'm going to have one larger motor and several smaller motors it would be safer to airstart the smaller ones, and in order to maintain a 5:1 thrust-to-weight ratio that one motor will have to be fairly large. <I>Unless</I> of course I choose to use 3 or 5 H motors... That's an idea.... But with clusters, cost starts adding up quick!<BR/><BR/>Thanks for your comments<BR/>~DanielDTH Rockethttps://www.blogger.com/profile/09222212036229618785noreply@blogger.comtag:blogger.com,1999:blog-1644326416987696055.post-29183602180821510262008-10-25T10:33:00.000-07:002008-10-25T10:33:00.000-07:00Really nice. I bet you could get this thing going...Really nice. I bet you could get this thing going on 3 G motors... it doesnt look too big. Use the new G80 maybe?High Power Rocketryhttps://www.blogger.com/profile/11537203640644706903noreply@blogger.comtag:blogger.com,1999:blog-1644326416987696055.post-82673556266593514672008-10-24T05:28:00.000-07:002008-10-24T05:28:00.000-07:00Very Nice. Good job on that!Very Nice. Good job on that!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1644326416987696055.post-73922822640172505872008-10-22T14:58:00.000-07:002008-10-22T14:58:00.000-07:00I saw your build thread over on TRF, its looking v...I saw your build thread over on TRF, its looking very nice. You've advanced pretty quickly it looks like. Hopefully I'll get some build time in soon so I can start on a larger project as well.Murdockhttps://www.blogger.com/profile/12483885002899485125noreply@blogger.com