Hence the joke and the . Sorry, it’s not always as funny when written out.I think we have made 6 flights with 1 recovery. It just disappears.
I built one last year and lost it on the first flight. 1/2A3-2T.
Hence the joke and the . Sorry, it’s not always as funny when written out.I think we have made 6 flights with 1 recovery. It just disappears.
Ya know your are in the LPR area of this forum, which has its own definitions of LPR. In MPR you could cluster up to four 30 gram, HAZMAT free, propellant F motors, although currently available choices will not get you to 320N.There is a case where I am considering a Cluster due to a single motor does not have enough speed off the rail.
This is for the booster of a composite 2-stage rocket. Main constraint is it needs to stay within the NAR & FAA Low Power rules, needs a 10 to 1 Thrust to Weight and lauch weight under 1.5kgm, this means average thrust of up to 147N. The one I did build is about 1.3kg but the highest thrust motor that can fly as a LPR is the G80. Max average thrust for LPR is 80N but 160N if a cluster. Therefore, two motors with average thrust of about 64N is perfect and there is are a number to chose from and still keep propellant weight under the 125gm FAA limit in F or G impulse classes.
Ya know your are in the LPR area of this forum
Yes, the case I outlined requires keeping the rocket in the LP Class 1 under NAR, NFPA & FAA rules.Ya know your are in the LPR area of this forum, which has its own definitions of LPR. In MPR you could cluster up to four 30 gram, HAZMAT free, propellant F motors, although currently available choices will not get you to 320N.
In your follow up math you only talk about stage 1 propellant weight... don't forget to add stage 2.This is for the booster of a composite 2-stage rocket. Main constraint is it needs to stay within the NAR & FAA Low Power rules
Why 10:1? I think the requirement for thrust-to-weight ratio is only 3:1, so long as everything else checks out.There is a case where I am considering a Cluster due to a single motor does not have enough speed off the rail.
This is for the booster of a composite 2-stage rocket. Main constraint is it needs to stay within the NAR & FAA Low Power rules, needs a 10 to 1 Thrust to Weight and lauch weight under 1.5kgm, this means average thrust of up to 147N. The one I did build is about 1.3kg but the highest thrust motor that can fly as a LPR is the G80. Max average thrust for LPR is 80N but 160N if a cluster. Therefore, two motors with average thrust of about 64N is perfect and there is are a number to chose from and still keep propellant weight under the 125gm FAA limit in F or G impulse classes.
2-stage with delayed sustainer ignition works much better with 10:1 else the rocket can start turning before sustainer motor comes up to pressure.Why 10:1? I think the requirement for thrust-to-weight ratio is only 3:1, so long as everything else checks out.
as in many things (Orange or Black, Honda or Toyota, three fins or four) there isn’t a right answer.However, it’s for this reason that I disagree with the idea that multistagers should be flown on the lowest impulse available. Sure, that’s a prudent thing to do for a test flight, but once successful recovery on an A8-0 to A8-5 stack has been achieved, why not swap that sustainer motor out for a B6-6 and go again? Why not work up to a C6-0/C6-7 stack and see if you can do that without having to replace either stage? That’s what I’ve been doing and I’ve learned much from that.
Having seen my converted Hi-Flier XL go on an E12-0/E12-8 stack for its first two-stage flight, I have to agree. It might have been the most thrilling flight I’ve had since getting back into flying. Watching the thing claw skyward on the booster for that long burn, then stage beautifully and shoot off to apogee, I doubt I’ll ever forget that.all that said, I will admit that a max stack (what, Comanche 3 with D12-0 to C6-0 to C6-7 on a low wind day) is a beautiful thing to watch, and even better if you get all the pieces back!
The coupler is a great idea... if it fits with a quad cluster... and from the looks of it, it won't.LOC uses removable plastic rivets. Build the motor mount in a coupler and secure the coupler with the rivets. Only drawback is surface mount fins. Check their instructions online.
Outside the box thinking.OK, I've started *thinking* about making a swappable motor mount that I can use to swap between a cluster of motors and a single. But I can't seem to quite figure out how to make it work so that it's secure and reliable and also, easy to work with. I'm currently thinking two screws to hold it in place, but that doesn't seem like it's really going to take the stress of many flights.
Maybe I need to contract the services of @lakeroadster to design something for me, but here's the rough concept:
The QUAD RUNNER is a BT-70 tube, or pretty damn close to it. I want to have a single swappable 24mm mount *and* a cluster of 4 18mm motors. If that can't work (because 4 18mm motor nearly fills that entire BT-70 space, leaving little room for any swapping/mount hardware) then a cluster of 3, or even 2 is fine. I'll just rename it the Duo-Runner... I was originally intending to just shove in the 24mm I had bought for it and rename it Mono-Runner.
My current idea is to glue in two strips of basswood into the body tube and use that as the centering rings guiderail and lock position by epoxying in two nuts that would hold everything secure once the bolts are screwed into via the drilled holes in the flamy-end of the motor mount's plywood centering rings.
4x 18mm fits in the 1.9" tube because that's the base config. Doing that same 4x 18mm in a 1.9" coupler should be the same as without a coupler.The coupler is a great idea... if it fits with a quad cluster... and from the looks of it, it won't.
Except for a given size a coupler tube is a smaller inside diameter than a body tube. In the photo, the (4) 18mm motors look tight in the body tube. Will they fit in a coupler?4x 18mm fits in the 1.9" tube because that's the base config. Doing that same 4x 18mm in a 1.9" coupler should be the same as without a coupler.
FYI: If the body tube is 1.9".... It's not a BT-70. A BT-70 is 2.217" o.d. x 2.175" i.d. (0.021 wall)... because 4 18mm motor nearly fills that entire BT-70 space, leaving little room for any swapping/mount hardware...
Roger that. I actually have the Q-Jet E26 in my range box right now, but (unfortunately), this isn't on the list of motors at the website. Flying my Big Daddy on that in 2 weeks. (See my Avatar, that's on a BP Estes E12, but I've since "graduated" to composite 24mm for that bird) Big Daddy loves more thrust, it seems the more you give it, the better it flies.The E30 is an expensive motor (2-pack is ~$30). For nearly half the cost, look at the Q-Jet motors. D22 and E26 could be options (2-pack is ~$18).
Very much so. I once saw one go on an Apogee E6. Arcing over under thrust is a pretty anxiety-inducing thing to witness.Roger that. I actually have the Q-Jet E26 in my range box right now, but (unfortunately), this isn't on the list of motors at the website. Flying my Big Daddy on that in 2 weeks. (See my Avatar, that's on a BP Estes E12, but I've since "graduated" to composite 24mm for that bird) Big Daddy loves more thrust, it seems the more you give it, the better it flies.
Yeah... but the E30 is freaking awesome. $6 upgrade... gets youThe E30 is an expensive motor (2-pack is ~$30). For nearly half the cost, look at the Q-Jet motors. D22 and E26 could be options (2-pack is ~$18).
You get what you pay for.Yeah... but the E30 is freaking awesome. $6 upgrade... gets you
Roger that. I actually have the Q-Jet E26 in my range box right now, but (unfortunately), this isn't on the list of motors at the website. Flying my Big Daddy on that in 2 weeks. (See my Avatar, that's on a BP Estes E12, but I've since "graduated" to composite 24mm for that bird) Big Daddy loves more thrust, it seems the more you give it, the better it flies.
My stock HiFlier XL flies really well on a D12-7, I can't imagine what altitude you could get by staging E motors. But then my stock XL might get similar altitude on an E30, but not as much fun.Having seen my converted Hi-Flier XL go on an E12-0/E12-8 stack for its first two-stage flight, I have to agree. It might have been the most thrilling flight I’ve had since getting back into flying. Watching the thing claw skyward on the booster for that long burn, then stage beautifully and shoot off to apogee, I doubt I’ll ever forget that.
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