Super Big Bertha 24mm D motor max...Had booster idea. Now a tail transplant to 29mm.
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Thank you! Had I known I was going to do the swap instead of a booster, I would have made those fin tabs longer(wider in length). If I can do this I'm very comfortable now building my L1 cert flight rocket for sure!coming along nicely
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Just did fin number 4 this morning(doing the fin tabs to motor tube and root cord to body tube on at a time). Still taking it one step at a time until everything is in place and firmly secure, should get it on its nose later and do the middle centering ring to body tube/fins. Ill also grab the syringe and hit that hole drilled for the upper centering ring, and get glue in the other side of that ring. Then in a work stand and its side(horizontally)to do internal fillets on the fins/motor tube. I'm going to probably just use thick and quick for outside fillets layer on, and do the CA on the fin edges probably right before paint. I'm also fixing the tips of these fins and they are all about the same length now. I sanded down one yesterday a little to get them all close....I'm not touching epoxy for this one. Time and patience are the best tools for this build. I moved the fin jig as number 4 was not tight enough to hold it the way I wanted it. Its the only one the foam board is a little bigger than the others fin slot wise. So I spun the jig and used under 2 slot for 4. For this build it was necessary to mark the fins as they are all a just a little different and it made assembly so much easier. Like I said for the first set of fins I've hand made in over 10 years they are not bad. It feels overall a lighter rocket too, I'm curious to see if it lost some weight. But the extra glue will make up for some of that but im only talking a few grams. Dry time, again..
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Set it on its nose, injected more than enough glue on the bottom of the top centering ring thru the little vent hole. Then used that syringe with the needle extension and made fillets to the centering ring, body tube, and motor tube. The one galley closest I put extra glue in because the top of the fin tab is a little away from the motor tube do to my inconsistency in making them. But its the only one, so I out some extra glue in that spot to go across the entire centering ring in to give it a little better hold. These fins are going to have glue in so many spots for the motor im using, and given a decent-decent rate. They will be more than fine. So much more of an improvement over the fins it originally had. Ill let this dry for a while. Then probably 2morrow do the inside fillets, and it looks like 2 outer fin to to body tube fillets on the bottom at the same time. When I get to the rail button spot I'll do that probably almost dead last. That way I can get around that button and backing plate. Then I'll be able to put that rear centering ring on, let that dry a little and then do JB weld for the retainer, but probably after primer/CA on the fins.
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I started the inside fillets, to the motor tube and body tube. I can do those 4 at once, this afternoon once its dry I'll flip it 180° and do the same thing again to the other side. Then ill have a few more turns of it(rocket itself) and body tube and motor tube to do. I put a little frogtape on the outside of the body tube and fin to make sure no glue seeps past that. If it's first it won't hurt anything I just didn't want it running down the body tube from inside. Its pretty much this slow process now...Ill update later today or 2morrow. It might look rough this phone shows every minor detail but it will button up nice. I'm still being mindful of the aft centering ring and rail button. Once I get that aft ring on its really just minor work, and getting the motor retainer on soon enough so it cures in time to fly this next Sat. I figure by Tues or Wed that should be getting put on, and then again its just waiting...
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That was dry so I flipped it 180° and did the motor tube and body tube to fins. It was a good idea putting frogtape on the outside as the one side I didn't tape the glue seeped through to the outside a little bit but its not a bad thing at all. I just wiped it off and that was it. The outer fillets will cover that. I'm still being extra careful not to make a mess for getting that aft centering ring on. After this I have four more fillets to do total inside so its going to be a glue, then wait, then spin, repeat type deal still. I'm more comfortable working with my left arm now but some stuff isn't perfect. But its a smaller body tube to work in anyways at a BT-80 really. Once this dries I'll do the last 4 fillets and the rail button. Then the aft ring, I'm not getting super close to the fin tabs torwards the aft end so I make sure I get a clean fit with the aft ring to those fin tabs. I'll do a dry fit first and might even leave the tabs on then just cut the tape off once its in. They will really help with installing that aft CR, ill think on that. But I'll goop it up and smush that ring down on it. Its going to be a pretty soild build hopefully.
A better way to use the syringe is to put it in a sealed container and just suck it out without the needle on, then add that and glue away. Really makes a huge difference having tools like this. And then just squirt the unused glue back into that container and wash the syringe in hot soapy water completely disassembled after every use. I've had them last a long time.
A better way to use the syringe is to put it in a sealed container and just suck it out without the needle on, then add that and glue away. Really makes a huge difference having tools like this. And then just squirt the unused glue back into that container and wash the syringe in hot soapy water completely disassembled after every use. I've had them last a long time.
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I let that all dry overnight. Got the aft rail button in and it was just a little off. So I elongated the hole, and got it where I want it after about 4 or 5 times of getting in and then adjusting it. I had to sand thr backing plate down just a little bit to clear the aft CR. I just used a Phillips head bit with some tape to pull it a little to the one side, and got it where I want it. Its not really off much im just picky about this stuff. I added some Titebond Quick and Thick to that so it dries a little faster than the TB II. Ill let that dry in place until probably later this evening. Then ill mock the aft centering ring, and button this up.
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In extremely happy on how this turned out. The one rail button wasn't quite right. So I used a screwdriver bit and tape to hold it in place while the glue dried on the backing plate. Well that worked, and then got the inside buttoned up. I left a little pc of that blue masking tape should I mess up I could pull it out(aft centering ring), I mocked this up about 5 times and made sure it fit pretty well before doing the glue. I stood it nosecone up afterwards so that glue I put on the inside dries and goes down on that aft CR. I used Quick and Thick for this, Titebond II is great, but it would have ran down the tube more torwards the forward end of the rocket. This stuff defies gravity and stayed right where I put it, which was a little above the fins on the motor tube and body tube. Then I pushed it down into the glue,(I got the top of the rail button with glue also) and that was pretty much it. Its very easy to mess up, and its kind of nerve racking especially on an older build you only really have one chance to get right. But planning ahead and being prepared helps ease those nerves, lol. After a few hours I'll flip it again, and do fillets on the outside of that CR.
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Well this is probably it for tonight. Flipped it and got the fillets done with a thin layer of glue over the aft ring on the outside. Its hard to get a good picture of it, and it looks like a mess but its just the camera. Anyways, thats going to dry until 2morrow. Then I'll do outer fillets, mess with the fin tips, and find that 29mm motor retainer then get it ready for primer...I'm really hoping for a flight this Saturday.
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I don't think you'll have a problem with your setup as long as you don't go with a stupid powerful 29mm motor. Those large Big "B" fins could be prone to flutter under high velocity but I think your poster board reinforcement might be enough to prevent that. Back in the day I'd go with .75 ounce fiberglass cloth and laminating epoxy. That is such a PITA to do and is time consuming. Also would add more weight to the aft end than your method. Are you going to sand the leading and trailing edges?
If not, the drag might be good to keep the apogee down if flying in a smaller launch site. Just paint 'er up nice, make sure the fully loaded rocket is within CG limits and let 'er rip. Make sure you base the delay grain time on multiple simulation runs if not using deployment electronics and know how to drill a delay to get the time to where you want it.
Drop in a Jolly Logic chute release and you can have what I call a "pseudo" dual deploy rocket. "Pseudo" in that one is not using ematches for both events. Use the motor to blow the "parachute pack" out and let the JLCR let it unfurl at a lower altitude.
For first flights, I'd use lower impulse motors to see how the rocket behaves with a full "in sight" flight and increase from there to whatever you're comfortable with. Best of luck. Kurt
If not, the drag might be good to keep the apogee down if flying in a smaller launch site. Just paint 'er up nice, make sure the fully loaded rocket is within CG limits and let 'er rip. Make sure you base the delay grain time on multiple simulation runs if not using deployment electronics and know how to drill a delay to get the time to where you want it.
Drop in a Jolly Logic chute release and you can have what I call a "pseudo" dual deploy rocket. "Pseudo" in that one is not using ematches for both events. Use the motor to blow the "parachute pack" out and let the JLCR let it unfurl at a lower altitude.
For first flights, I'd use lower impulse motors to see how the rocket behaves with a full "in sight" flight and increase from there to whatever you're comfortable with. Best of luck. Kurt
Yeah well have a little issue I just found....ugh. Ill get this taken care of, and respond later to all you said... lol..
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That repair started, I cut a small pc of body tube. Then sanded down a coupler. Got things squared up, and glued the new body tube to the old coupler. Once again it's gonna be a one pc at at time. While this drys im gonna mess around with new shock cord options. But honestly it being apart and having that chute baffle its not going to make a difference..More work begins...lol..
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Ok, yeah this was really a booster idea that turned out so nice I thought why not swap it. Its a 10 year old build and I expect this to be a little off. Now that I'm dealing with the coupler issue(which is totally my fault and I've changed how I assemble them and have for some time) I had some time to write back. I'm going to start it out on something very small, honestly probably something to just take it up high enough for a successful flight. Ill mess around with OpenRocket first to see what simulations say with what motors I have. But like you said I'm not going to be putting any ridiculous motors in this. I have an adapter that I use for some of my builds(29mm to 24mm). It allows me to go fly them locally and then put something bigger in them for club launch days. But im dealing with that little inconvenience, which is being fixed now. I do have a JL chute release and will probably use that if I do get into higher impulse motors, but I'm going to be taking it very easy with this. Its more a low and slow rocket now, but with the capability to do more.
But dealing with this coupler issue It will be ok. I'm using a small pc of body tube and a coupler I sanded down to fit this all together. I'm also keeping it in mind that it has to be straight, lol. It already has crash damage so its not perfect anyways. A quick fix would have been just to glue it back together. Had there been a little more coupler I would have done that. I know where I went wrong years ago and thats doing two body tubes into the same coupler minutes apart. Which I don't build like that anymore. I do one piece into the tube and then the other a few hours later. I was pressing to get this in the air Saturday but that might not happen right now. I really appreciate the response and thank you. I have about the same thoughts on what you wrote. I haven't built these in a long time so this is all jogging my memory as how to, and how not to build them. Its a minor setback but not a major one. Thanks again I appreciate any and all feedback! Michael B.
Well the new body tube section was dry. So I watered down some elmers just a little bit. That really helps me with installing these couplers in the body tubes especially if you need rm in a certain spot. But I used a brush then after stirring it up good, and coated the inside of the new body tube, and then put the coupler in. On the inside I smeared the excess glue that came thru all around thr old coupler and new coupler/body tube. Ill let thisbdry a while then fit the top. I'm debating while this drys to just do the motor retainer too but I really want to wait. And I fit it together it looks like a win. And yeah I stressed tested the top half...
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Well while that's drying a little more and it was dry enough to mock fit the top. I just pushed the top tube all the way down. Then spun it to align the lugs. Used a straight edge and made sure the rocket was straight and It is from fins to nosecone. Then I got my launch rod and put it in both lugs and slightly moved it to make sure the rocket goes up and down smoothly. It was perfect then so I used a sharpie and marked it so when I'm putting it together I can line up those marks. I'm going to wait a bit yet because if I have to twist that that yellow tube firmly to line it up, I don't want to risk anything just previously put together but not that strong yet moving. So ill let it set in front if the fan and I flipped it so each side gets air to the stuff that I smeared in the inside of the couplers. That's it until later on. I have some other non-rocketry things to do..
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I was looking at this piece and I feel it's going to strong enough to hold the two parts of the rocket together. I mean the coupler only comes out of the yellow tube anout a half inch to where the scissors are. And then the body tube is glued to that as seen above. And the new coupler is pushed right against the old one with glue on all of that. I think its going to hold up pretty well, anyone else have some thoughts on that? I mean it had a small contact area but its basically one giant body tube coupler. Its better than gluing it back together like it was when I pulled it apart. It was just a tiny little sliver and I started to push on it and eventually it came apart. It was luck saw it now and not later on it wasn't very noticeable at all. But, I'm going to let that dry for a while then dry fit the top a few times and out it together. Then let it sit overnight and see what 2morrow brings.
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Well I glued the top part on. Its about as straight as they come. Its got some crash damage so its a little tweaked on just the one side, oddly its not completely straight in a little spot. But the other spots(all the way around the tube)the straight edge sits perfectly flat against the whole rocket. So I just might let it stand vertical for a little then lay it back down in the cradle for all of this to dry until 2morrow morning, and ill start some filler work.
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Got some JB mixed, and put the motor retainer on. I made sure for a few mins aftwr it didn't work its way up. And I used my adapter to make sure its centered perfectly. That can all dry tonight and 2morrow I'll probably start fin fillets, filler.
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I let that dry overnight, its all good. Now I started the outer fillets with Titebond Quick and Thick. Ill let them dry for an hour or so then go to the next 2. Usually I can do all of them at once but I'm m going to do 2 at a time with this one. Since that picture I've gotten that little bubble out of the left side fillet and wiped off the body tube in the middle.
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I took about 15 or 20 mins to sand down the fins and those 2 gaps in the body tube, I even got down in the gaps. Ill sand that filler(its white Gorilla wood filler)down later after I get back from my appt. Then maybe one more layer of that stuff. If it doesn't need anymore filler, ill hit it with spray bomb primer/filler. Then let it all dry until Saturday, but it will be dry way before that. I did a layer of CA on the outer fin edges too after I sanded them down a little more. Ill see what they look like later then if they need one more layer in spots ill do that before primer.
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