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Big Daddy... 38mm.

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ttabbal

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I love my 29mm version, so I figured, why not 38mm? :cool:

The Big Daddy is also the kit I like to experiment on, so this will be my first fiberglass experiment. I'm planning to glass the tube and tip-to-tip the fins. I'll be using Aeropoxy for the build, and I was thinking of using some 3oz fabric. I also have some 10oz, but that seems a little much for this project.

Fins: 1/8 ply? I've tossed around using the included balsa fins, but even with glass that seems a little weak.

For glassing the tube, I don't have the stuff to vacuum bag. I was just going to rotate it while curing. Any better ideas? If I do anything fancy, I'm going to need release agent. Recommended sources?

I will, of course, be adding noseweight. I'm fiddling with Rocksim to decide on the amount.

I realize I'm nuts, but this is to be flown at Hellfire. I'll have a huge field of salt to find it on. :) I might even find a spot for my beeline to make the job easier.
 

DAllen

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First, I think the you might want to consider how you are going to fly it. 38mm motors come in a variety of sizes from G to J. Are you going to try to go supersonic? If not, I really doubt you're going to need much more reinforcement than what you're planning. 1/8" ply with a layer of 3oz glass is going to be fine IMHO.

Nose-weight is huge obviously but remember, you can get away with a smaller margin of stability with stubby rockets. Apogee wrote an article about this but I can't seem to find it at the moment. I would try to come up with a simple system of adjustable nose weight.

Please share build photos!

-Dave
 

ttabbal

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First, I think the you might want to consider how you are going to fly it. 38mm motors come in a variety of sizes from G to J. Are you going to try to go supersonic? If not, I really doubt you're going to need much more reinforcement than what you're planning. 1/8" ply with a layer of 3oz glass is going to be fine IMHO.

Nose-weight is huge obviously but remember, you can get away with a smaller margin of stability with stubby rockets. Apogee wrote an article about this but I can't seem to find it at the moment. I would try to come up with a simple system of adjustable nose weight.

Please share build photos!

-Dave

No plans for supersonic flights. I think if I push it, I might be able to shove the 38/600 case in there, but it wouldn't leave much room for anything else. I'm thinking mid-I motors will be the max I will likely fly in it. Though I suppose I could get pretty fast with the various Warp-9 type loads.

I've read the articles Apogee put out. I should re-read them though to help me determine the noseweight. I went overboard with BBs and epoxy in my 29mm version and likely compromised the altitude I can reach with it. It still flies great though.

I'll take some pics as I go along and post them in this thread. I know how you guys love build threads. :) Now I need to go find a Big Daddy kit to start messing with.
 

novikov

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Glad to see i wasn't the only one thinking along these lines... I am planning to pursue my Level1 cert this November at a local launch. My thoughts so far had been along the lines of using one of the longer engines and boring out the nosecone opening so the ejection charge is mostly contained there and help eliminate the need for the wadding and such.

i am still poking at it in rocsim to see what i can come up with. I was contemplating using the Bluetube material on this as well. we shall see what happens though.

i will be keeping an eye on this thread to gain other ideas as well.
 

troj

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I used to have a 38mm Big Daddy.

The fins were stock, laminated with 4oz fiberglass, then fiberglassed to the motor mount. I extended the fin slots to the bottom of the tube, so that I could then slip the tube down over the motor mount/fin assembly.

I didn't fiberglass the body; left it alone.

The rocket flew four times -- I161, two H flights (I forget which motor), and a G69. I lost the bloody thing on the G69.... :rolleyes:

-Kevin
 

DAllen

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No plans for supersonic flights. I think if I push it, I might be able to shove the 38/600 case in there, but it wouldn't leave much room for anything else. I'm thinking mid-I motors will be the max I will likely fly in it. Though I suppose I could get pretty fast with the various Warp-9 type loads.
Welp then...A tracker might be a good idea.

-Dave
 

JimJarvis50

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I have two Big Daddy's. My 29 mm has flown maybe 50 times on F and G motors, with a few H flights. My 54 mm (below) has flown 4 times, all on pro54 2 grain motors. Goes to about 9,000 feet or so, but there is no altimeter, so I don't know for sure. I launched it at NSL a few weeks ago.

This one has the balsa fins and cardboard tube with one layer of carbon on each. The fins are surface mounted. The nose cone is hollowed out, and the inside is coated with epoxy/fiberglass to strengthen the plastic. There is some lead in the nose, and Rocsim says it's one caliber stable with a 2 grain motor. If flies great (with tracking transmitter of course).

Jim

NewBigDaddy.JPG
 

ttabbal

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I've got a beeline, I'm still playing with ideas for mounting it though. The current favorite is between the body tube and motor tube with a hole in the upper CR for the antenna to go down toward the aft end of the rocket. Need some way to hold it in place, the medicine bottles I usually use won't fit. :) Maybe a little box epoxyed to the inside of the body tube with a little fiberglass for strength?

I'm going to cut the bottom off the nosecone and let the motor extend up in there. Recovery will probably just pack in along side the motor tube. Kevlar shockcord, kevlar loops epoxyed to the MMT and inside of the nosecone should work to keep it all together.

That 54mm is a beauty, JimJarvis50! I considered trying that as well, for the AT "beer can" case. I might still do it on a future version. Do you have a rocksim file you are willing to share for it? Balsa fins with carbon? Wow... I might have to try them with fiberglass just to see. :)

I just got the CRs sanded to fit the BT. Nothing interesting for pics yet, but I could post one with the CRs and MMT dry-fit I suppose. :)
 
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troj

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Your idea for alongside the motor mount sounds like a good one.

Just mount the BeeLine to a board, and slip the board into place. Then, you can attach the board in place to hold everything where it belongs.

-Kevin
 

JimJarvis50

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That 54mm is a beauty, JimJarvis50! I considered trying that as well, for the AT "beer can" case. I might still do it on a future version. Do you have a rocksim file you are willing to share for it? Balsa fins with carbon? Wow... I might have to try them with fiberglass just to see. :)
Thanks! I'll attach the file, but I don't know if it will do you much good (I only enter the final weight and CG, not the components.

I cut off the bottom of the cone, and with the 2G motor, there's plenty of room up there for the tracker and recovery. There might even be enough room for a 3G motor, but I think that would be the end of the road for it.

Jim

View attachment New Big Daddy.RKT
 

n5wd

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I've got a beeline, I'm still playing with ideas for mounting it though. The current favorite is between the body tube and motor tube with a hole in the upper CR for the antenna to go down toward the aft end of the rocket.
Remember that you can put a replacement stubby duck antenna on the beeline and shave 3 or more inches off the antenna length.
 

n5wd

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That depends on your BeeLine -- older ones don't have SMA connectors on them.
Mmmmmmm... forgot about that. I know Greg can retrofit the SMA on there, though some might be happy with the 1/4 wave spike.
 

ttabbal

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Mmmmmmm... forgot about that. I know Greg can retrofit the SMA on there, though some might be happy with the 1/4 wave spike.
Mine is the older version with the spike soldered to the board. I could add the connector, but the unit works great as it is. It's a little long, but nothing I haven't been able to find room for. I'll keep that in mind should I need a smaller space for it in the future though.
 

ttabbal

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Thanks! I'll attach the file, but I don't know if it will do you much good (I only enter the final weight and CG, not the components.

I cut off the bottom of the cone, and with the 2G motor, there's plenty of room up there for the tracker and recovery. There might even be enough room for a 3G motor, but I think that would be the end of the road for it.

Jim

Thanks. I'll check it out later. I've started cutting the bottom of the cone off on almost all my HP rockets. Those plastic bases just don't have much strength. I've seen too many of them break loose to trust them anymore. :)
 

JimJarvis50

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Thanks. I'll check it out later. I've started cutting the bottom of the cone off on almost all my HP rockets. Those plastic bases just don't have much strength. I've seen too many of them break loose to trust them anymore. :)
For mine, after I cut off the bottom of the cone, I applied a layer (or 2?) of fiberglass cloth around the base. Then, in the entire portion of the cone above the shoulder, I applied an epoxy/milled glass coating to the inside of the cone. And then there is the epoxy/lead in the tip of the cone that included an eye bolt for the shock cord. I mention this because what I really ended up with was an epoxy/fiberglass/lead cone with a plastic veneer over it. All of the strength/sturcture was in the material I added and not the original plastic. With something approaching a pound of lead in the nose, this approach was required to hold it in place.

Jim
 

ttabbal

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Thanks! I'll attach the file, but I don't know if it will do you much good (I only enter the final weight and CG, not the components.

I cut off the bottom of the cone, and with the 2G motor, there's plenty of room up there for the tracker and recovery. There might even be enough room for a 3G motor, but I think that would be the end of the road for it.

Jim

Hmmm... Rocksim 9 can't read it. I get an error and it doesn't look like the XML from the other sim files I have here. :confused2:

Is it compressed or something?
 

JimJarvis50

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Hmmm... Rocksim 9 can't read it. I get an error and it doesn't look like the XML from the other sim files I have here. :confused2:

Is it compressed or something?

No, just an old version.

All dimensions are the same as the kit, since i didn't change anything. Weight without motor is 34 oz with CG 8.25" from the nose. Gives 1 caliber (Rocsim) stability with a 2G motor. The simulations are to 9000 feet right at Mach 1.

I'll fly my 29mm version tomorrow on a G80 for about the 50th time. Never gets old.

Jim

Jim
 

JimJarvis50

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Jim.... Is this yours?
Yes, I think so. I had planned to use the new J-250 sparky (that would have been cool), but I had to settle for the smoky sam version instead, the J-280. The LCO had to think about my flight card for a few moments before he pushed the button.

Nice Pic!

Jim
 

BsSmith

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Yes, I think so. I had planned to use the new J-250 sparky (that would have been cool), but I had to settle for the smoky sam version instead, the J-280. The LCO had to think about my flight card for a few moments before he pushed the button.

Nice Pic!

Jim
That flight was spectacular!

I was standing at my car when it went up, so I could follow it all the way up. There is nothing like seeing that 1/2 mile long smoke trail!
 

JimJarvis50

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That flight was spectacular!

I was standing at my car when it went up, so I could follow it all the way up. There is nothing like seeing that 1/2 mile long smoke trail!
Thanks. It amazes me how well Big Daddy's fly.

Jim
 

ttabbal

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OK, I finally got some work done on this thing. :)

Here are a couple pics. The parts with the MMT and CRs assembled. And the body tube on the stand with glass applied. I've got 2 layers of 3oz glass on there, nice and smooth. First time doing a tube, I think it turned out pretty good. I'll know more in the morning when I can pull it down and cut the ends of the glass off.

I just used the stock cardboard CRs that came with the kit and some masking tape to connect it to the dowel. The stand is just some scrap 2x4 wood screwed together and clamped to the table.

IMG_2965 (Medium).JPG


IMG_2966 (Medium).JPG
 

rdmmdr

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and i thought i was nuts with the j350 in the 4 inch goblin

great pics though

stuck a g in a stock big daddy, came off the rail straight but at about a 100 feet it took a sharp right and then looked like a cruse missle heading to bagdad. it impacted under power and only snaped one fin off. the do make those stouter then you would think.
 

oddmanrockets

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my big daddy doesnt take a 38mm mount but i put a 24 mm with 4 18mm mount F 39 with 4 c60s airstarts
 

AHansom

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Good luck with the 38mm Big Daddy. I have a Big daddy with a 29mm motor that has a couple dozen flights using G-77's and once with a H motor. I use a black 36" parachute that helps with the visual traking but takes awhile longer to come down. One of the guys at our club shoots his Big Daddy off with a J-800:y:. Just before launch they always anounce a reward for whoever brings it back and it always seems to get back to him. The only picture I could find is in a very old newsleter look about about half way through.

http://www.tripolicentralcalifornia.com/newsletters/da04.pdf

Andy Hansom
 

Threemorewishes

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Here's mine about to go up on a CTI I540. It's going to fly at LDRS28 on a CTI J335 Red Lighting. If you are going to be at LDRS we could have a drag race. I'm in parking space A146 if you want to get a race going.

 

ttabbal

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A J800?!?!?! Sheesh. I'm surprised he fit the case in there. I did my L2 with that motor in a Vertical Assault. Awesome flight. I can't imagine that motor in a Big Daddy.

I'm afraid I won't be at LDRS, but if you ever make it to Hellfire look me up. Any of the UROC guys should be able to point me out. Great looking rocket though, I'd love to see it in person.

The only issue I have at the moment is that the Aeropoxy is still tacky. Is that normal? It's been a few days now, I would think it would have finished curing. The tube itself looks great, no bubbles or dry spots. Feels very strong. The nose cone is getting some treatment as well. Some 10oz cloth from the shoulder to about 3/4 the way up, and I'll add some epoxy with milled glass for the rest and to hold the noseweight in. Planning about 10oz right now, but I haven't finished the rocksim model yet.
 

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