Big Daddy... 38mm.

[JimJarvis50]

The only issue I have at the moment is that the Aeropoxy is still tacky. Is that normal?

What hardener did you use? The 3660 or 3665?

Just curious about your cone. Did you cut off the bottom of it? Mine have had bottoms, which when I cut them off, leave an area where the shoulder isn't very long (the spot where the shock cord connection is supposed to go). I don't see that part on your cone.

Jim

 

[ttabbal]

What hardener did you use? The 3660 or 3665?

Just curious about your cone. Did you cut off the bottom of it? Mine have had bottoms, which when I cut them off, leave an area where the shoulder isn't very long (the spot where the shock cord connection is supposed to go). I don't see that part on your cone.

Jim

I cut the bottom off the cone. The shoulder is about 1.5" long now. Not quite as long as I would like, but I can get a coupler and make it longer if I need to.

The hardener is 3660. I mixed it by weight and if anything there is a little too much hardener in there. Though I tried to get it very close. I mixed it very thoroughly as well. It seems to have cured well, it's very tough now. Just a little sticky. Not how I have seen cured epoxy end up in the past. It's usually almost glassy.

 

[JimJarvis50]

I cut the bottom off the cone. The shoulder is about 1.5" long now. Not quite as long as I would like, but I can get a coupler and make it longer if I need to.

The hardener is 3660. I mixed it by weight and if anything there is a little too much hardener in there. Though I tried to get it very close. I mixed it very thoroughly as well. It seems to have cured well, it's very tough now. Just a little sticky. Not how I have seen cured epoxy end up in the past. It's usually almost glassy.

OK, I understand what you did with the cone. I left more of the part that could be kept longer, but the cone isn't even on the bottom. I think what I did is perhaps better because of the amount of weight I have in the top of my cone, but then again, I don't know how much strength the lower portion of the shoulder actually provides.

By the way, I use shearpins on my nose cone. Might help with your shorter shoulder.

If you cure the 3660 at about 90F, you might have better results (more like what you expected).

Jim

 

[Pantherjon]

I had the same kind of curing problem when I glassed the tubes on my 54 Special(will eventually be finished)..I knew it was cured but was still sticky..I placed a desk lamp with a 100 watt light bulb in it turned on next to the tube to get some heat to the tube..After a couple hours the stickiness went away..Weird how the hardener can be finicky like that.

 

[ttabbal]

Interesting about the hardener needing more heat. I'll have to try getting it warmed up. Even my garage is getting close to 90F these days.

I'll try the shear pins as well. I need to add some to my larger rockets as well. Early main deploy is a pain.

 

[Threemorewishes]

LDRS 28 was great. My Big Daddy survived two neck snapping launches. The first was on a 38mm CTI I297 - Skidmark to 7000+/- feet hitting Mach 1.01.

I spent almost two hours looking for it. Some one picked it up and returned it to the registration table while I was following a moving signal on my Walston....Thanks, but GRRRRR.

The second launch was on a 38mm CTI I800 - VMax to 5000 feet hitting 0.8 Mach. It did have a whopping 2050 feet/second/second of acceleration.

This time I walked right to it using the Walston all the while keeping my eyes open for helpful rocket returning people.

Now its time to plan for a 54mm slightly upscaled Big Daddy in fibreglass clothes.

 

[ttabbal]

Hmmm... The epoxy is still tacky after a week in the garage. So I stuck one of the parts into a toaster oven set for 150F for an hour. We'll see if that helps. If it does, I'll have to come up with something for long tubes or bigger parts. The instructions say it will cure at room temp. :bangpan:

I won't be using the oven for food of course. I bought it for soldering so it's no big deal to put epoxy in there.

 

[ttabbal]

No joy on the heat. Owell. I'll paint it. :confused2:

Got the MMT installed. Of course, I forgot to put the kevlar recovery harness in. So I'll have to cut a new CR to hold it in. No biggie.

 

[ttabbal]

I got some more work done. Here are the fins being glassed. I decided to just use the balsa fins with more glass, so it's a layer of 10oz with a layer of 3oz on top, cut at 45 degree angles to the bottom layer. I read somewhere that adds strength, no idea if it's true, but it doesn't take any extra effort, so why not try it? The fins that have glass on both sides feel very strong.

I have one more glass lamination for the fins to get done, getting to the home stretch now. I'm planning to fly it at Hellfire on 7/31, so it's about time to get this thing finished.

Now I need to get the nose cone finished. Just need to add more nose weight and the recovery harness. I think I'm just going to epoxy some kevlar strap in there in a loop with the Aeropoxy adhesive. Maybe with some milled glass mixed in. I need to mix up some of that for the BBs in the nose cone tip anyway.

I'll probably add a wrap of the 3oz glass for the 4" or so of BT I have above the tip-tip glass to transition it a little. Mostly for looks. Oh, and come up with some kind of mount for the beeline and install the rail buttons.

 

[JimJarvis50]

I got some more work done. Here are the fins being glassed. I decided to just use the balsa fins with more glass, so it's a layer of 10oz with a layer of 3oz on top, cut at 45 degree angles to the bottom layer. I read somewhere that adds strength, no idea if it's true, but it doesn't take any extra effort, so why not try it? The fins that have glass on both sides feel very strong.

I have one more glass lamination for the fins to get done, getting to the home stretch now. I'm planning to fly it at Hellfire on 7/31, so it's about time to get this thing finished.

Now I need to get the nose cone finished. Just need to add more nose weight and the recovery harness. I think I'm just going to epoxy some kevlar strap in there in a loop with the Aeropoxy adhesive. Maybe with some milled glass mixed in. I need to mix up some of that for the BBs in the nose cone tip anyway.

I'll probably add a wrap of the 3oz glass for the 4" or so of BT I have above the tip-tip glass to transition it a little. Mostly for looks. Oh, and come up with some kind of mount for the beeline and install the rail buttons.

Those fins should be plenty strong. Looks very good!

You've probably already done this step, but if not, rinse out the cone with alcohol to get any release materials or contaminants off of the plastic. Also, if you use a large amount of epoxy in the tip, you might want to put the tip in water to keep it cool.

Jim

 

[ttabbal]

Those fins should be plenty strong. Looks very good!

You've probably already done this step, but if not, rinse out the cone with alcohol to get any release materials or contaminants off of the plastic. Also, if you use a large amount of epoxy in the tip, you might want to put the tip in water to keep it cool.

Jim

Thanks for the info. I sanded the inside of the nose cone with 80 grit and wiped with an alcohol soaked paper towel. I've been doing the epoxy/BBs in the tip a little at a time, so it hasn't had a lot curing in there at once.

I think it's looking good. The fins are done and the rail buttons installed. I'm glassing a matchbox to hold the beeline transmitter. I had scrap fiberglass, so I figured, why not? I think I'll just hold it in place with a couple removable rivets. I'd love to stuff an altimeter in there somewhere, but I'm not sure how yet. Maybe an accelerometer based unit, to prevent the BP charge from harming a barro sensor.

So far, weight is about 1.5 pounds. I've got another 4oz or so of noseweight I'm planning to add. There is also the main recovery harness and chute to add.

 

[ttabbal]

Well, it had a great first flight. Unfortunately, I undersized the chute and it came down a little hard. One fin broke, but it's fixable. Looks like the balsa let go along the fin surface. Some epoxy and a clamp should fix it easily enough. I think I'll cut some G10 for future projects. It will fly again after some work and a bigger chute. Great flight on a CTI H123 skid. I didn't manage to catch the flight with my camera, but a pro photographer did. I'll be purchasing a pic of it from her.

 

[JimJarvis50]

Well, it had a great first flight. Unfortunately, I undersized the chute and it came down a little hard. One fin broke, but it's fixable. Looks like the balsa let go along the fin surface. Some epoxy and a clamp should fix it easily enough. I think I'll cut some G10 for future projects. It will fly again after some work and a bigger chute. Great flight on a CTI H123 skid. I didn't manage to catch the flight with my camera, but a pro photographer did. I'll be purchasing a pic of it from her.

Yea, that's sort of the problem with the Big Daddys. They go high and they're single deploy, so you skimp a little on the chute and then the fins get knocked off once in a while. I just glue the fin back on and do it again. Looking forward to the picture.

Jim

 

[Threemorewishes]

My buddy was able to get this picture of my Big Daddy at LDRS 28. CTI I297 Skidmark in all its glory. He was unable to capture it on the CTI I800 Vmax.

 

[DAllen]

He was unable to capture it on the CTI I800 Vmax.

I800 VMax in a BD?! :y: Well of course he wasn't able to get a shot of it. :roll: Jeepers, that thing had to be pushing mach when it left the rod/rail.

Regardless, nice shot! Thanks for sharing.

-Dave

 

[Handeman]

My buddy was able to get this picture of my Big Daddy at LDRS 28. CTI I297 Skidmark in all its glory. He was unable to capture it on the CTI I800 Vmax.

Great shot of the Big Daddy. Telephoto lens sure are great! It's hard to believe those trees in the background were 2 miles away.

 

[DMcCauley]

Nice design, but way overkill in my expert opinion.

The only modifications you need to make for the Big Daddy is to replace the stock fins with plywood fins and paper centering rings for plywood rings. No other reinforcements are necessary.

I've built (2) high power big daddy rockets in this configuration with 38mm motor mounts and the biggest motor flown so far was an I1299 Warp-9. I typically fly the H999 Warp-9 in this rocket.

I'm building a 3rd this time using a 54mm motor mount and again, no additional reinforcements.

 

[JimJarvis50]

I'm building a 3rd this time using a 54mm motor mount and again, no additional reinforcements.

The Big Daddy can use either 1, 2 or 3 grain 54mm motors depending on how you build it. The 2 grain makes a really nice flight. With no modifications other than plywood fins on the paper airframe, the speed you will get will be near or above Mach 1. Pulling this off would be an accomplishment for sure, and I wish I could be there to see it.

Jim

 

[DMcCauley]

The Big Daddy can use either 1, 2 or 3 grain 54mm motors depending on how you build it. The 2 grain makes a really nice flight. With no modifications other than plywood fins on the paper airframe, the speed you will get will be near or above Mach 1. Pulling this off would be an accomplishment for sure, and I wish I could be there to see it.

Jim

The H999 almost breaks Mach, but the I1299 Warp-9 definitely puts it well over Mach 1.

 

[Threemorewishes]

Rocksim has the CTI 5 grain I297 at Mach 1.01 and the CTI 4 grain I800 at 0.8 Mach in the Big Daddy pictured above. It flies with the supplied balsa fins. They have fibreglass on the fin roots and the leading edge.

The I297 cracked the paint along all the fin roots. A quick smear of epoxy, some black marker to hide the missing paint and up it went on the I800. No issues at the lower top speed of the I800.

The next flight for this rocket will be the J335 Red Lightning. Will the balsa fins stay on this time?

 

[slogfilet]

I was thinking of putting together a 38mm BD for the practice in 'glassing. I'm sure it'd be considered "overkill," but would the additional weight help with greater altitude on higher power motors? In RockSim, it looks like the optimal mass is quite a bit higher than stock form...

 

[rocket999]

My buddy was able to get this picture of my Big Daddy at LDRS 28. CTI I297 Skidmark in all its glory. He was unable to capture it on the CTI I800 Vmax.

WOW!!!:jaw:

Now I need to build one. :headbang:

Sam

 

[ttabbal]

I was thinking of putting together a 38mm BD for the practice in 'glassing. I'm sure it'd be considered "overkill," but would the additional weight help with greater altitude on higher power motors? In RockSim, it looks like the optimal mass is quite a bit higher than stock form...

That was why I built mine. I wanted practice with glassing and I like modding Big Daddy kits.

I agree that it's likely overkill, but it was more about practice with new materials than the most efficient build. I noticed the "optimal mass" in rocksim as well. I have no idea on that count. I did manage to squeeze my beeline in there, but I didn't have room for an altimeter. I might be able to stuff one in between the fins in a compartment. But then I'd have to cut a door in there and add hardware to secure it for the flight.

 

[slogfilet]

Thought I'd bring this thread back from the dead!

I'm finishing up my 38mm Daddy and have a concern about the chute. I cut the bottom of the nosecone off, and the mmt extends about an inch above the body tube.

If I pack the chute around the mmt and the nose cone goes on around it, will it make a difference if i have the nc attached to the end of the shock cord, as opposed to the chute attached at the end, with the nc about 1/3 of the way down?

I usually put the chute at the end, but I wanted to make sure the nc was able to "pull out" the laundry (otherwise I'd be afraid the nc would pop off with the chute inside it, and it would remain stuck.)

Any thoughts? Having the chute at the end would give me more effective shock cord length.... maybe I'll just add a couple extra feet to be safe.

 

[ttabbal]

Thought I'd bring this thread back from the dead!

I'm finishing up my 38mm Daddy and have a concern about the chute. I cut the bottom of the nosecone off, and the mmt extends about an inch above the body tube.

If I pack the chute around the mmt and the nose cone goes on around it, will it make a difference if i have the nc attached to the end of the shock cord, as opposed to the chute attached at the end, with the nc about 1/3 of the way down?

I usually put the chute at the end, but I wanted to make sure the nc was able to "pull out" the laundry (otherwise I'd be afraid the nc would pop off with the chute inside it, and it would remain stuck.)

Any thoughts? Having the chute at the end would give me more effective shock cord length.... maybe I'll just add a couple extra feet to be safe.

Mine is set up similiarly. An AT 38/600 fits in there pretty good, but leaves very little room for the recovery. What I did was pack the kevlar shockcord around the MMT And the chute with kevlar protector up in the nosecone. I put the cone on the end of the cord with the chute about 2ft from the cone. I use a 15ft kevlar cord from Giant Leap. I love those things. I flew it a couple weeks ago on an I195J, amazingly fun flight. I love Blackjack and Skidmark motors. Not the most thrust, but fun flights.

The recovery system was really packed tightly with this setup, but the NC has about 8oz of noseweight. I also used shear pins, in part to keep the NC on as it was compressing the recovery gear a bit. 2 #2 nylon screws IIRC. It worked quite well. The weight of the NC seems to help deploy the recovery.

One of these days, I'll get a lift-off shot. This thing is FAST. It doesn't help that I keep putting I motors in there. I should try with a big G or small H.

 

[JimJarvis50]

Thought I'd bring this thread back from the dead!

I'm finishing up my 38mm Daddy and have a concern about the chute. I cut the bottom of the nosecone off, and the mmt extends about an inch above the body tube.

If I pack the chute around the mmt and the nose cone goes on around it, will it make a difference if i have the nc attached to the end of the shock cord, as opposed to the chute attached at the end, with the nc about 1/3 of the way down?

I usually put the chute at the end, but I wanted to make sure the nc was able to "pull out" the laundry (otherwise I'd be afraid the nc would pop off with the chute inside it, and it would remain stuck.)

Any thoughts? Having the chute at the end would give me more effective shock cord length.... maybe I'll just add a couple extra feet to be safe.

My 54mm version is set up with the chute between the fin section and the nose cone. However, the chute is located about 1/3 of the way up from the fins to the chute (i.e., closer to the fins than the nose cone). The reason for this is that when the chute opens, the fin section will go screaming past the chute. With my configuration, the fin section won't slam into the nose cone, which could happen if the longer part of the cord was between the fins and the chute. This is just patterned off the generally accepted approach for a dual deploy setup, where again, you don't want the fin can slamming into the upper portion of the rocket when the drouge deploys. I'm not sure this is critical or anything, but with Big Daddy's, the nose has a lot of weight in it.

The only other thing I do is to wrap some duct tape around the kevlar at the point where it would contact the edge of the body tube. Maybe 8 wraps at most around the 3/16 Giant Leap kevlar. This is to help prevent a zipper.

Jim