Discussion in 'Low Power Rocketry (LPR)' started by James Duffy, Jan 28, 2016.
Tell us how it flies? I would love to hear your launch report!
Tip: Don't use plastic glue to attach the fins to the wrap.
One good bump and they will fall off.
I re-glued them with CA. Much more solid.
What kind/brand of plastic glue did you use? What locations was it applied?
CA actually does not bond to styrene as well as styrene glue bonds to styrene.
I will say that if something is going to break on a hard-enough landing, I'd prefer for a fin to pop off than to rip the vac-formed wrap.
I am pretty sure I used ABC plastic for all the new injection molded parts. I am also pretty sure the the wrap isn't styrene, but I may be wrong. I'll have to go through a bunch of notes to find that info. I used both Tenax plastic glue and CA to hold the fins on. CA actually worked better for me but your right it rips the wrap while the plastic glue just lets go and the fin pops off. For those that decide to use CA I applied a good amount of it to the inside of the fin fairing. I then placed the body on top of the fin. If you were to place the fin over the body, " Fin on Top" the glue could and will run out of the joint.
Do you feel this Little Joe II would make a good sport scale model for a NARAM entry?
I think it would make a good Sport Scale model for NARAM. There are areas where better builders could make the model more accurate, depending on which mission they model and what they do to try to make it more accurate (and how well they do so since poorly done extra detailing is worse than not having it. ). So in a scale room with say 6 of the kits entered, if they were all built to the same craftsmanship level, the judges would give more points for the ones that had enhanced accuracy.
- George Gassaway
I'm going to be in Houston next week, and on Monday the 22nd I plan on spending an hour or so at the Saturn V display at Houston Space Center. If anyone wants pictures of anything specific from the Little Joe on display right outside that building send me a PM or an email, and I'll do my best to get it documented.
+1 on everything George has said. Another opportunity to enhance competitive potential would be to tweak the flight profile by using a cluster similar to those flown on each specific mission. Yet another tweak might be to place a staging motor in the base of the Apollo capsule to simulate the operation of the Launch Escape System.
One really cool option would be to simulate the in-flight breakup of flight A-003, followed by the LES operation. Pull that off and you'll be a contender for a top finish!
If anyone wants pictures of the LJII at the New Mexico Space Museum, I'm usually over there once a month for a launch.
Here are some photos.
This would probably be a question for George Gassaway. Is the Little Joe II CM that is on display in New Mexico & Houston accurate for any of the actual missions flown? It seems like the Little Joe II on the displays have command modules with the Radiator panels in the wrong locations. The CM look closer to an actual Saturn CM and not a LJII CM. They don’t match the drawings or historical pictures of the vehicle on the launch pad.
I guess it would depend on the interpretation of the the term "reasonably representative"...
From the Pink Book:
I can ask the museum staff if they know which flight they used as a prototype.
Here is what Tom Beach wrote about the remaining Little Joe-II hardware on display:
The only Little Joe that flew with a “real” SM, was A-004, which had a Block I SM which had those unique (taller than wide) horizontal radiator panels near the middle-upper body, not the short very wide ones at the base on Block II (Presumably A-004's Block ISM was empty inside other than necessary structure, no tanks, probably no common Apollo SM electronics other than anything the Abort system might have needed, definitely no engine). The JSC and NM Joes have Block II SM's.
The JSC Joe is a 12-50 series body, that was built for fixed fins. But they "stole" a set of 12-51 series moveable fins and most of the fin root fairings (which covered RCS thruster and elevon related tankage & components), and stuck them in place.
The NM Joe is 12-51-4, meant for moveable fins. But with its original fins stuck onto the one at JSC, it has fixed fins on it. Except.... it does have the front parts of the fin root fairings, just handing there. So that looks funky. Also that means the front part of the fairings on the one at JSC were custom-built and are not quite right. Also, the Algol motor nozzles do not look right. For one, the real ones in the outer locations were angled. For another, the nozzle cone angle was not that wide. So whatever they are..... they are not right.
So, those display rockets do not represent anything that flew. The Pink Book rule about modeling display rounds…. was intended for one thing 40+ years ago when it was HARD to get scale data on a lot of rockets, and “sport scale” (judged by eye based on drawing and/or photos) did not even exist, for Scale you HAD to have dimensions so it could be measured for accuracy. So that rule was created in large part to allow for actual measurement of rockets on display and in museums. But over time that original intent became twisted, slippery slope syndrome gone wild ( Such as a ridiculous pink and blue Redstone missile that took a place at a NARAM a few years ago, due to a children’s book of an artist’s drawing of it in pic and blue that was used in the data pack).
I’ll just say if I was a scale judge and someone modeled a “museum” rocket that did nor represent the real rocket it was supposed to, I’d give it very low scores (I’d have given the pink and blue Redstone zero points for color accuracy).
There is no rocket as well documented as the Little Joe-II is, so to me a serious scale model of either of the two on display would be silly to enter in scale competition.
Having said that, those rockets can be quite useful for additional documentation of various details (Indeed, that is how Tom Beach derived a few dimensions, measuring what he could reach on the New Mexico Joe. And many years ago, I got fin thicknesses and Air Rudder dimensions for Redstone rockets by measuring one on display in Huntsville). A person could enter drawings/photos of the real mission being modeled, then from a display rocket include images showing relevant details from one of those two, like say systems tunnels or fin elevons, or the base ring, or longerons, and point out other judges those are from display rockets but are being used as generic supplemental detail images (Of course, such photos would need to be showing details that were the same on the mission being modeled).
Around 1990 or 1991, I took photos of the BP-23 CM at MSFC (It flew on A-002). Of course it was hidden under a BPC, so the CM self was not directly useful but it did help. The biggest help was the LES Tower and Skirt/nozzles it had. Since it was just sitting on its boilerplate heat shield on the ground, the LES tower and escape rocket were a lot closer and easier to photograph details (However, the Escape Rocket itself is is too short, is either plain pipe or the LES motor only without any of the other parts on top of it such as the Sep motor, pitch motor, and other parts). Unfortunately I do not have access to those photos. But attached is one I Googled.
John DeMar, you said you do a launch at the ISHoF once a month. When we drove to NARAM, we stopped there for a short visit (Friday before NARAM, July 24th). There was some sort of apparent student rocket contest going on. All flew the same design. Pic below. Wonder if you were there?
- George Gassaway
OK, I am posting this separate, regarding nozzles. Below is a pic I took last summer of the NM Joe, with the simulated Algol motors:
And below, a photo of the real thing, A-002's Joe during a test-fit assembly at the Convair plant in San Diego:
Note that the nozzle has not had the dark covering put around the upper part of it as was added for flight.
BTW - this also gets into something I've been considering.
Either to start a Little Joe-II Data/Photos thread n the TRF "scale" section, or ask the mods to create a special place for them.
So, this 1/45 kit build-oriented thread will be less cluttered, and a dedicated data-photo thread can be in place without the clutter of build stuff.
And I have a really big reason for thinking about such a thing. Actually had considered it in recent weeks anyway. But due to a recent discovery, well, there is a massive amount of online archive photos that have been located. The image above is just a small example.
The image below is another. That is a straight-nozzled Algol for the center, of either QTV or A-001, at White Sands. Being lowered into the aft body. They installed all the motors from the top, bolting them in place to the base ring, then lowered the upper body in place and secured it at the STA-227 Splice Ring. Then secured the tops of the Algols to an upper ring-web assembly in the upper body.
So, James, John B., and others, what do you think of a separate thread for Joe-II data & pictures?
- George Gassaway
Very nice build!
I think having a separate Little Joe-II Data/Photos thread is a fantastic idea. With all the drawings & pictures available it's a scale modelers dream.
Nope, I wasn't there. The launch site our club uses in Alamogordo is the site of NSL2010. It is not associated with the museum, although our groups help with programs there occasionally. There are two NAR sections an hour apart, one in Alamogordo and one in Las Cruces, that have some membership in common. The two TRA prefectures combined into one a few years ago when I was prefect.
I finally completed the wrap files, printed them, and had them photocopied since the toner holds up better than inkjet.
I’ll document how to trim and attach them later. Just wanted to give an advance look of the model with the SM wrap and BPC wrap. I'm applying them in a manner that allows easy replacement, for now at least.
The LES motor wrap is currently wrapped around a 3/8” tube to pre-curl it so it will be easier to apply it to the motor tube Thursday. Also, the Thruster Quads will be added later (probably last parts added).
Draft reduced size file of Service module wrap.
I will post PDF files of the wraps later.
- George Gassaway
Very, Very nice looking model.
Quote Originally Posted by JumpJet
Very, Very nice looking model.
I agree George, great work, above and beyond!
Not sure if the Testors tube glue I used to glue the fins on was old or what but while doing some light sanding on the primer a fin popped of rather easy. I checked them after originally after gluing and they seamed solid. I popped the other 3 off rather easily and am reattaching them with Rocketpoxy. We will see how they hold. I would have tried thick CA but I didn't have any.
Hmmm. I used the Testor's "red tube" glue and so far, so good. Barring a dumb accident like dropping it, I guess I'll find out when I fly it and it lands.
BTW - In general, epoxy does not bond to plastic very well. It "sticks" to plastic, but a lot of epoxies can literally peel off from a lot of plastics. For the times when that cannot be avoided, for the epoxy to get a better "bite", many builders will often sand or otherwise rough up or scratch the mating plastic surfaces.
Since you mentioned you were doing some sanding of the primer..... I assume you did not apply primer to the wrap before you glued the fins on? Because if the wrap was painted before gluing the fins, the fins are not glued to the wrap, the fins are glued to the paint, and paint does not bond to a surface as glue does. I'm pretty sure you did not do that.... but want to be sure.
The other thing though is that if you were say sanding primer on the Service Module part of the tube, why not put the primer on the tube and sand it smooth first, before applying the wrap? OK, the instructions didn't say to do it in that sequence. And that is not excusing fins that pop off too easily, but a building risk / complication / hassle to mess with primer after the fins are on if it could have been done to the body tube earlier before attaching the fins and other parts (if it was indeed the tube).
On my Joe, I may be ready to call it "done" by Saturday night. It's not that it's taking me a lot of time to finish it up, just juggling other things. And running into a few learning experiences with the wraps that I'll mention later (Had to go to OfficeMax to re-copy some wraps due to paper quality / brightness mismatch). I do have the SM Thruster Quads painted, so other than redoing the CM/BPC wrap and applying the Escape Motor wrap, gluing the thruster quads on will be the last of the "building". Though that's not including the recovery system being attached, and not including the little General Dynamics/Convair plaques (I have those drawn up, but do not have the clear decal paper to print them on and apply over chrome tape to get the correct look. So that may be awhile but in the meantime I might put some temporary ones in place, simply printed onto paper and applied with a low-tack adhesive. And man they print so tiny that....I could have used a Klingon font and some might not notice.)
And I'm starting a totally different project (glider, not scale) which I wanted to get a jump on so I could get it far enough along to see if I needed to go to a hobby shop across town to get any supplies Saturday or not. Otherwise I try to avoid simultaneous builds, prefer series builds. I had to spend some time researching it and making up templates.
- George Gassaway
Actually I was sanding on the fin with some 320 grit to remove a hair from that somehow got on it. I love my dog but sometimes her hair get on things when you don't expect it. Checked the fins this morning after drying overnight they seam ok we will find out. I always thought plastic glue sort of melted the two parts together. I want to have it finished to fly next month at the new field in SC.
I understand most people are ditching the clay weight that comes with the kit, and adding solder or lead shot to the LES tube, but has anyone determined exactly how much weight this kit need to be stable?
My rule of thumb for the Little Joe is that it should balance at the "N" of "UNITED STATES", or forward, to be stable. When it has been a little behind the "N", sometimes the models have gone unstable.
This assumes the lettering is properly placed. I ought to check the drawings and generate a 1/45 scale location for that.
There can be some variances in building that can cause some models to be more tail-heavv than others. Also, if you ever plan to use a 24mm reload, those weigh more than a D12 or expendable composite like the E30, so will need more noseweight. That is also the case if clusters are added, or any conversion to a 29mm motor.
I said it on Facebook but not here. A 29mm conversion might fly VERY nicely on an Estes E16 or F15 (but converting to 29mm would mean cutting a custom rear ring to move the Algol mount holes outwards a bit). But absolutely would need extra noseweight.
Currently I have some solder/lead noseweight in a 13mm tube that I'll put inside the LES motor tube. It weighs 40 grams. Before I glue it in, I'll assemble a 24mm reload, put it into the mount, and see if the balance point is forward enough or not. if not, there is room for more in the LES nose.
OK, I just did a check with a D12 in it and 40 gram noseweight in the LES motor tube. It is balancing at the middle of the "N", so it's good (I think it would be OK down to the bottom of the "N", but a bit more stability margin is good). A reload will move the CG back. But I plan to use a 36" flare parachute which will add a bit of weight ahead of the CG. So I need to do a final check with a prepped reload case and chute inside, before gluing the LES motor tube forever. So, take note that 40 grams seems good for my model for a D12 or expendable E. I'm NOT saying 40 grams is the correct mass for all models if it is in the LES motor tube, just for this one I have built.
The clay in the kit weighs about 45 grams, BTW.
- George Gassaway
Thanks for the stability tips George. This issue of the Estes Little Joe II has brought me out of hibernation. I not have flown any model rockets in a few years and I prefer flying with black powder motors as opposed composites or reloads due the simplicity and availability of BP motors.
As far as what motor to use I always gone with what it says "on the box". Estes recommends a E30 composite for the Little Joe, but if I understand you a D12 might work as well? I'm a believer that scale models don't need to fly high, just high enough to safely deploy their chute, so everyone can see the flight.
It is interesting that the Estes 2016 Catalog mentions the D12-3 and E12-4 for this kit. Weather is a factor, it seems that they would be fine on a very calm day, but with any wind, the E30 would be a better choice. I remember reading that the tester wasn't happy with a couple of the flights, so to be safe in all conditions they now only recommend the E30.
So, I wanted to get a nice photo of the model outside, clear blue sky, moon in the background.
Set it up on a pad. It was windy, the model rotated around the rod a bit. I was dealing with that. And then….
While on the rod, the end of the body tube had been supported on the 3/8” post. But the last rotation due to wind, it slipped enough to no longer be held by the 3/8” post, and fell down about an inch to the lower launch lug, then hit the lug. Well, that hit knocked lower lug off, letting it fall more, and of course the top lug broke off. So, the model fell to the ground and broke off all four fins!
So, yep, as Brent mentioned, the very plastic cement shown in the instructions….. does not glue the plastic fins to the body wrap like it should.
And does not glue the lugs on properly either. If I had used Plastruct's liquid Plastic-Weld for the lugs, I think they would have held, but I was concerned about it running and not filling gaps like tube glue so went with the tube glue.
I am REALLY ticked off that the WRONG glue was shown in the instructions. If I had made a different choice for a glue and it worked badly, that would be my fault. But the instructions just say Plastic Cement, and shows a tube of glue just like Testor’s, including the same oval shape where the name is on the Testor's tube. No warnings to use a special glue that bonds ABS to styrene.
So, yeah, anyone who has built theirs with tube glue that is NOT formulated to bond ABS and styrene together, your fins (and lugs) are likely to pop off far more easily than they should.
Can anyone recommend a glue that will join ABS to styrene, that i am likely to find locally or in a hobby shop? I do not want to wait to mail order some, unless absolutely necessary.
So far I have found this online but do not know if I may be able to get Weld-on 16 locally.
Now, I DO have Plastruct’s Plastic-Weld in a bottle. But it is so thin that I’m concerned that it would run. I need to use anther kind of “thick” high viscosity cement.
Below is a photo of the model, showing one of the fins and the main body. All of the Testor’s glue is on the inside of the fin, none is on the wrap, it is totally glue-free. Also, sad surprise now….. I had added the General Dynamics / Convair plaques.
I do not know when I'll fix it.
- George Gassaway
Sorry to see that George. At least the tower didn't snap off.
I'll probably use a bit of CA on these parts when I build mine, especially the launch lugs. I'm not sure if that's the alternative you're looking for though.
Possibly having part of the wrap rip off is a bit concerning but more so is having important parts fall off with just the slightest jolt or movement. Losing a fin in flight due to an improper glue bond would be especially bad.
I'm not a plastics expert, but I use Loctite Epoxy for Plastic. On every bond I've tried to date it has held and seems super strong. You might look at the data sheet and see if it might work for you: http://www.loctiteproducts.com/tds/EPXY_PLSTC_S_tds.pdf.
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