XXTREME BLUE

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Mdutch

Well-Known Member
Joined
Nov 12, 2011
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Location
Rochester, NY
Hi all,

I've been building this rocket on and off for a while now and I'm ready to continue and hopefully I'll finish it up soon. I'll start by copy/pasting the build from a previous post off a different forum, so here goes:

So here is my next project, I actually started this about four years ago. I guess now is as good as any time to finish it.


'XXtreme Blue'

There is all 6" blue tube for the airframe. Starting on the left is the fin can/motor mount. It has 1/2 plywood delta fins mounted thru the wall to a 4" motor mount with an Areo Pac motor retention already assembled. At the top of it you see the BluT coupler, inside it is a section of sliced BluT to make the coupler a double wall construction. The short section to the right is the drogue bay with the altimeter bay in the top of it, the Alt bay will also be Dbl wall const. To the right of that is the Main chute bay along with a pile of cut bulk heads cut out of 3/4" birch plywood. Then to the right again is the conical nose cone,
the whole rocket will be +/- 12' tall.
I'll add more detailed photos to our URRG forum as soon as I get started on the project.



FYI; the big tubes, FG nosecone and FG fins you see behind this and in the blue recycle bin are for a Nike Smoke project that will be a future build sometime in the future. (This is another project I have been collecting parts for since LDRS 31)

IMG_20160222_153548_509.jpg
 
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So I'll start with finishing up the fin can coupler. Since I wanted to use a double bulkhead for the top I had to go down to the local rocketry parts supply center mistakenly called Home Depot to acquire a 'U' bolt with threads long enough to extend out both sides of the doubled bulkhead.

.IMG_20160229_095547_464 (2).jpg
Though you can't see it here the threads at the top have a nut and washer on them to help compress the bulkheads together.

This assembly will be the harness attachment point at the top of the fin can/motor mount section of the rocket
 
Here are the coupler parts.
IMG_20160229_095547_464 (3).jpg

I'll start by epoxying the bulkhead in. I'm using 15 minute Bob Smith Industries epoxy here and adding some micro balloons to thicken it up so it will stay where I want it to. I also want it to seal the bulkhead in for an epoxy step later.
IMG_20160229_100152_388.jpg

Here you see the interior of the coupler with the bulkhead epoxied into place.
IMG_20160229_120535_437.jpg
 
Here you see the exterior of the coupler assembly, it is recessed for a reason that will be explained later.
IMG_20160229_120819_171.jpg

OK, so now the coupler is epoxied into place.
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Here you'll also see the altimeter and drogue bays ready for the next step in the build.

What you can't see too well is that on both the interior and exterior of the coupler I poured in enough epoxy to embed the 'U' bolt nuts so they will never come loose.


One last thing I should point out is the pressure relief hole I drilled into the top of the coupler bulk head which will make sliding the 98 mm motor in and out of the fin can sssoooooo much easier.
IMG_20160308_131654_088.jpg
 
Here is a view of the aft end of the fin can/motor mount with the Aero Pac retainer in place. you can also see where I took two short sections of coupler, I cut one to slide it inside of the other, then I glued this into the end of the tube to help the end to be less likely to be damaged due to hard landings.
IMG_20160301_131503_322.jpg

Here you see the Aeropac motor retainer (sans the screw cap) done so to better view the aft end. Although I did use the screw inserts that come with the retainer you can see that I like to embed the screws in epoxy as well.
IMG_20160308_131946_983.jpg

One should note that even though you can get the cap to screw all the way down onto the screw heads, when you place your motor case into the retainer, that the cap will not go all the way to the screw heads then. Especially if you are using a snap ring case.
 
Since the whole air frame is blue tube I won't be fiber glassing it, but I do need to fill the spirals before painting it.
The other day I picked up a tube of glazing putty and here you see that I've done the Altimeter Bay and I'm working on the Drogue Bay.
The glazing is easy to use, it dries very fast, and you can easily sand off the excess.
IMG_20160311_133429_373.jpg

I still have the Main Bay and the Fin Can to do, I also have some saw kerf marks to fill on the fins, but for that I'll use Bondo as they are a bit deeper than the spirals are.
 
So I started working on the Altimeter Bay.
IMG_20160312_180640_633.jpg

Here you see the four sections of all thread that are spaced so I can put two of my altimeters in the bay.
I have all of my altimeters mounted to the same type of sled so I can install anyone of them in any of my Alt bays.
(This includes any of my rockets from a 3" air frame up to a 7.5" airframe so far.)
You also see how the 'U' bolts are mounted here. The space between the bulk heads is approximately the distance of the inner sliced coupler which the bulk heads will sit on. There is a lot more I do with this but for now this is ready for the two couplers to be epoxied together.
IMG_20160313_110507_069.jpg

So here the Altimeter Bay is epoxied together for now. I still have to install the charge contacts and wells yet, and the key switches but I'll show that in detail as I do them.
So for what I did here I first assembled the two couplers and then bolted the bulk heads in place. Then I slid the inner coupler assembly out and prepared my epoxy using US Composites 3 to 1 mix I did a batch large enough to coat the inside of the outer coupler and then used West systems adhesive filleting blend to make part of the epoxy thicker which I spread on the Drogue side of the bay. Then I slid the inner assembly into the bay and set it aside to cure.
IMG_20160313_110438_497.jpg

Not to start a glue thread here but this is what I like to use for epoxy. I used to use all West System but found US Composite to be of the same quality at half the price. What is nice is that the West filleting blends also work with US C.
The 405 is nice because you can add as much as you like to get any consistency that you need from syrupy to a heavy thick paste.
Actually the 405 can even be used in BSI epoxy but one should note that the thicker you make your mix, the shorter the cure time will be.
 

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Now I'm working on the charge connectors, I'm making 4 lead sets for this rocket. Each lead is a length of 26 gauge two lead wire, two connectors soldered on and some shrink tubing. With an 8-32 screw and nut through the connector.
IMG_20160315_193830_416.jpg

Here are the two drogue sets installed in the bottom of the bay.
IMG_20160315_194645_978.jpg

The interior walls are shiny due to being coated with epoxy.
Here is what it looks like on the exterior of the bay.
IMG_20160315_195038_358.jpg

Each lead now has a couple flat washers set between two nuts, once you go to install your e-match on the leads you place the stripped end of the lead on the screw post slipped in between the washers and then tighten the top nut. This gives you a good solid through the bulk head connection to your ejection charges with out the possibility of the burnt BP harming your altimeter(s). Also the charge wells are just CPVC pipe caps. I have a 8-32 screw holding each cap thru the bulk head. CPVC is stronger than PVC as it is used for water supply lines. It is not aluminum but it does hold up quite well to several charge events before you need to replace them, and their much less expensive than aluminum too.
 
Here is the top bulk head of the Altimeter bay.
IMG_20160316_154230_728.jpg

IMG_20160316_154254_120.jpg

You can see the leads and the charge wells here. As this end is towards the main chute bay I'm using bigger charge wells here. The Drogue end has 3/4" caps and the Main end has 1" caps. You can see that I have used the 1" caps once before. They do still have a lot of life left to them so I'm not worried about their integrity as of yet.

While I was at it I also soldered leads onto my key switches seen here.
IMG_20160315_195345_248.jpg

I like using these barrel switches because they are durable and easy to use and install. Normally you need to drill a 1/2" hole and install them with a back nut. But I have found that if you drill a 7/16" hole you can start them and then use a crescent wrench to finish screwing them in. Of course you have to file a couple flat areas on the outer flange like I did on these to use a crescent wrench.

I will say this method works best with cardboard, phylonic, or thicker air frames. You will probably need to use the 1/2" hole back nut installation on thinner fiberglass airframes for these switches
 
Here are the two switches installed:
IMG_20160322_155437_157.jpg

As I mentioned before, due to the thickness of the airframe I was able to screw these switches in alleviating the need for the back nut.
IMG_20160322_155359_912.jpg

Take note of the stop nuts on the threaded rod, they are what my altimeter sled rests on, by installing a second nut at the top of the sled it will keep them from shifting up or down in the bay.
 
So this is one of my sleds that are a standard build that fits most of my altimeters.
The battery clip is a standard 9 volt battery holder.
IMG_20160321_191201_484.jpg

It should be noted that this battery holder has a solid post-to-post connection. It was pointed out to me by a fellow TAP member that the 9 volt holders that use a spring loaded connection clip in them have the potential to lose their electrical connection if mounted upside down.

This here is one of my Perfectflite MAWD's, the tubes mounted on the sides of the sled are spaced to fit on the all thread that I have mounted in the altimeter bay.
IMG_20160321_191117_133.jpg

I have most of my Perfectflite MAWD's and Stratologgers mounted on this size sled.
 
I have been needing to make new sled to fit my MARSA54L altimeters but I still want to be able to use them in most of my rockets.
So this is what I've come up with:
IMG_20160321_184902_697.jpg

IMG_20160321_190525_602.jpg

This following photo shows how both altimeters will fit into the altimeter bay.
IMG_20160321_191409_024.jpg

As you can see here none of the charge wires or switch wires are connected, and neither altimeter is all the way down onto the stop nuts. But you should be able to get the idea how everything is mounted and attached from this photo.
 
So I know it was my intention to have this done by URRF 3 but I wasn't able to complete this by then so I guess now that URRF 3 has been an astounding success I guess it's time to begin working on the rocket again.

So we sort of left off with filling the spirals with glazing putty and I have most of the air frame done as shown in this photo of the fin can/motor mount section:
IMG_20160702_090155_582.jpg

As you can see I have one side and fins done here, I still have the other two sides to do as well as the main chute bay section. Once all the spot putty is done and sanded it will be time to apply primer and make sure I have all the spirals filled to satisfaction. When I'm happy with all of the rocket I will continue with the final painting.
 
Why did you coat the inside of the Ebay with epoxy?

Well Fred,

I suppose I could claim that by doing so that I was trying to give more strength to the two layers of coupler sleeves. But that really wouldn't be true since the epoxy won't soak all the way through from one layer to the other. And by itself epoxy has no added strength. I guess it's really just a habit I had gotten into when I was building single deploy rockets from way back when. I use to coat the interior of the air frame from the motor mount up to the nose cone shoulder to help make cleaning the BP residue from the ejection charges easier. And it's most likely an unnecessary habit since I don't ever expect, or even want there to ever be any BP residue in the altimeter bay.

So what can I say, old habits huh.
 
Mike,

Good answer - because I couldn't come up with why....
Old habits do indeed die hard.

Happy Fourth!
 
So I know it's been a while but I finally got back to spot glazing the rest of the fin can/motor mount.
IMG_20160806_084845_654.jpg

Now to do a little sanding and then on to the main parachute bay. I'll have to do something about locating and mounting the unistrut buttons in a bit.

I sure hope the rest of this build doesn't take a few more years.
 
Holy Crap, I really need to finish up this build. Let's see, since I just posted it as a BFR for URRF 6 I guess I'm committed, (or committable), I suppose we'll see which.
 
2.5 years later! Good luck with the finishing and flight. This was a good build thread.
 
Actually looks like I have to fill the spirals on the main parachute bay and provide some backing where needed to install the rail guides, then I need some warmer weather to do some painting. Also want to test fit everything again and make sure everything still fits together OK.
I'll post a picture when I get to that point.
 
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