Biggest scratch build yet - Bluto

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That's crazy! Have you flown that thing with all nine motors?
The highest flight, 12500 feet, was on a single N800 [YOUTUBE]_smH9D6BAhM[/YOUTUBE]
The most motors was a M1850 with 4 J350 airstarts (8500 feet) [YOUTUBE]MW5XtJ5Vkr4[/YOUTUBE]
Unfortunately, when I used this rocket to demo a Gorilla M1665...M1665 Cato.jpg
 
I've actually looked at full sheets of plywood, and bigger than the Michael's sheets at two specialty hardwood suppliers, and at Woodcraft. I've also looked at hardwood plywood at Lowe's and Home Depot. The problem is finding straight stock. The bigger sheets that I've looked at are always warped. The Michael's sheets are 12" x 24", and I can usually find really nice and straight pieces. The 1/2" sheet was $9 before the 40% coupon.

I've had good luck with Hugh's hardwood in the past, though I haven't purchased from them for a while. In the past they let me sort through the stack for straight pieces.
 
Okay, I've decided to add four 29mm outboards, even though I'll NEVER use them. Honest. Never ever. Anyway, I was playing around in Open Rocket, and for some reason, when I add a J250 and two H97's, it gives me 269 ft. That can't be right. What am I doing wrong?

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View attachment Bluto SD_3_outboards.ork
 
looking at your OR file it seems that your recovery devise opened while motor was still burning. The delays on the H motors are set to zero, so that would; I think explain it.

Great build so far and good luck,

rocketgeek101
 
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looking at your OR file it seems that your recovery devise opened while motor was still burning. The delays on the H motors are set to zero, so that would; I think explain it.

Great build so far and good luck,

rocketgeek101

But the J250 had an 18 second delay. I just added 18 second delays to the H97's, and now it says 1751 ft. I guess that was the problem. Thanks!

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When you select the delays enter in "none". Then you should get 1750ft.
 
Dang it Jim, now that I've fiddled around with your OR file, I gotta build me one. :cheers:
 
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Okay, I've decided to go with four 29mm outboards. I just ordered the 29mm motor tubes. I'll be making three 1/4" plywood centering rings. I'll put a single tee nut next to each outboard, and two tee nuts next to the 54mm tube for retention.

Now why can't I permanently plug all four 29mm tubes? They'll be 16" long, which will fit all the way up to 6 grain XL cases. I can't think of a reason not to plug them. I've also decided that if I ever DO use any of the outboards (which I won't, ever), I'll probably just fly it as a cluster, and not mess with air starts. In which case, I would definitely use CTI reloads, since they light so easily. But it doesn't matter, I'll never launch it as a cluster. Ever.


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Okay, I've decided to go with four 29mm outboards. I just ordered the 29mm motor tubes. I'll be making three 1/4" plywood centering rings. I'll put a single tee nut next to each outboard, and two tee nuts next to the 54mm tube for retention.

Now why can't I permanently plug all four 29mm tubes? They'll be 16" long, which will fit all the way up to 6 grain XL cases. I can't think of a reason not to plug them. I've also decided that if I ever DO use any of the outboards (which I won't, ever), I'll probably just fly it as a cluster, and not mess with air starts. In which case, I would definitely use CTI reloads, since they light so easily. But it doesn't matter, I'll never launch it as a cluster. Ever.

So why are you putting them in?
 
Okay, you seem adamant that this will never be flown as a cluster...so don't put them in. I'd rather see you build it with a 75mm central and no outboards, then adapt to 54mm for the bulk of your flights.

Now, if I were putting in outboards, I would have them pass through the first two centering rings, but not through the fore ring. Put the fore ring far enough in that the 6G case can be inserted without hitting the fore CR. I did this on my 5.5" Nike Smoke that has 4x 29mm outboards.
 
Okay, you seem adamant that this will never be flown as a cluster...so don't put them in. I'd rather see you build it with a 75mm central and no outboards, then adapt to 54mm for the bulk of your flights.

Now, if I were putting in outboards, I would have them pass through the first two centering rings, but not through the fore ring. Put the fore ring far enough in that the 6G case can be inserted without hitting the fore CR. I did this on my 5.5" Nike Smoke that has 4x 29mm outboards.

I'm definitely not going to put a 75mm mount in it. I can barely afford the 54mm hardware.

See, I have this reputation of saying "no", then doing it anyway. When I became a BAR, and attended my first club launch, I decided I'd build and fly an LPR here and there, but that would be it. I would be satisfied attending launches and watching others launching their big rockets and spending the money. Or so I thought. I said no to Level 1, then said no to Level 2, then said no to a mile high rocket (I've built the rocket, just haven't flown it yet). So now I'm saying no to a big rocket with outboards...
 
next thing you know we'll be seeing pictures of his rockets at the far away cell at LDRS...:)
rex
 
Then, since you will "never do clusters and/or air starts" as you cut the holes for the outboards,
you should never put in the hatch & plumbing for the airstart timer. :wink:
 
Yes, you will not want to be chopping into it after you paint it. Air starts are cool. All you need is a simple hatch and a tube to thread an igniter through, but you have a lot of room so I would use a seperate tube between each pair of motors.

Good luck!
 
Then, since you will "never do clusters and/or air starts" as you cut the holes for the outboards,
you should never put in the hatch & plumbing for the airstart timer. :wink:

Yes, you will not want to be chopping into it after you paint it. Air starts are cool. All you need is a simple hatch and a tube to thread an igniter through, but you have a lot of room so I would use a seperate tube between each pair of motors.

Good luck!

You guys are bad influences!
 
You guys are bad influences!
:)
The hatch should be at least as big as your hand so you can work easily on it. You can glue a wood block in each corner of the opening so you can put a short screw through each corner of the hatch. You can easily retrofit a board in there later. Here is a board that was retrofitted in a friends rocket after we hacked a hatch in it. It is mounted inside the bay with one wood screw into one of the fins near the motor tube, it is all that is needed. A shunt sticks through a hole in the hatch and gets cut before flight.

ForumRunner_20130103_213919.jpg

You can do all of this later.
 
It's allot easier to adapt down and nearly to impossible to adapt up afterwards.
I had a Bruiser EXP that I put 12-14 flights on before the electronics failed and buried itself.
I wish I had put a 76 mm in it.....
You won't be going that fast and lucky if you hit a mile on a single motor.

I glassed mine and it weighed a bit more @ 29 lbs loaded; With 3 motors: 54 mm +2 x 38 mm.

Over the years I have heard " I'll never do that" more often than I can count.

Ultimately it's up to you but, things change.

JD


I'm definitely not going to put a 75mm mount in it. I can barely afford the 54mm hardware.

See, I have this reputation of saying "no", then doing it anyway. When I became a BAR, and attended my first club launch, I decided I'd build and fly an LPR here and there, but that would be it. I would be satisfied attending launches and watching others launching their big rockets and spending the money. Or so I thought. I said no to Level 1, then said no to Level 2, then said no to a mile high rocket (I've built the rocket, just haven't flown it yet). So now I'm saying no to a big rocket with outboards...
 
I started on the new centering rings. I printed out a template, and marked the locations for all the holes with a center punch. Then I cut out the three 1/4" squares, clamped them together, and drilled a 5/32" center hole through all three. The center holes will be for the screw in my circle cutting jig.

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I got all three circles cut out with the bandsaw, then drilled out the center holes with a 1/4" bit. Mounting them on the lathe, I got them cut to their final size.

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I put a 1/4" bolt through the center holes, and a #10 machine screw through one set of 3/16" holes, to keep the centering rings oriented while I drilled all the holes. It will also hold them together when I cut the 29mm holes. I had to drill a shallow hole in my drilling block with a spade bit to clear the head of the #10 screw.

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I cut the holes for the 29mm motor tubes with a 1-3/16" hole saw, then enlarged them to fit with the Dremel. I cut the center holes for the 54mm motor tube with a 2-1/4" hole saw. They required a tiny bit of sanding.

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