Binder Sentinel

OKOKOK, I know I always cheat you guys out of pics, so I'm gonna post a few of the construction of my Binder Sentinel. This is gonna go really slow, and the construction is pretty sloppy, so be kind. First up, a pic of the BT's. The brown one had the glassine peeled up and has 2 layers of nylons on it. The black one has the glassine left on it and has one layer of nylon on it.

The MMT assembly with the 2nd ring measured to where it should be flush with the front of the fins. The top ring is glazed with epoxy due to Mike's warning with the masonite and water. The second one will be sealed in with the fins, the aft centering rings, etc. so I skipped it.

Looking good so far Kermie!

Keep it up!

More pics!!!!!

I sure as heck hope yours flies straighter than my Binder Sentinel did. I think one of the fins got glued on slightly warped, or possibly one of the forward fins didn't go on straight. Both times I flew it, it ended up flying horizontal. $120 down the drain

Yeah. I know what you mean. The fins are small for the size of the rocket and instability could be an issue. One of the reasons I love the zipperless design is that it removes a lot of the instability questions by moving all of the recovery forward.

Anyway, here's the epoxy well cementing the front of the motor mount to the body tube. I apologize for the quality of the pictures. I'm fighting with both a lousy monitor and a lousy digital camera as well. I have to alter the brightness of the picture and hope I'm getting it close to where you can see what I see.

Tacked the fins on as well. Getting them all in straight is deforming the end of the BT just a touch, so I'm going to do interior fillets from the fins to the MMT next, skip the interior fillets to the BT, get the aft CRs back in there to force the BT back into shape and then glass the fins tip to tip.

Looking really good Kermie!!! Your plans for the glassing sounds good. One question: What exactly is the purpose for using the nylons on the tube? Since it does not add much strength, I imagine it's just for an even surface on the tube, but that's me

Keep up the good work and buy all of your composites and epoxies from www.uscomposites.com , They're the best that I have tried!!!!

I think you'd be surprised how much strength it does add. The polycrylic doesn't dry as hard as epoxy does, so it doesn't add the stiffness that an epoxied glass tube does, but it adds a considerable amount of both stiffness and tensile strength. I'd wager you'd have a helluva time zippering this combination.

Anyway, here's an aft view. I got too lazy to widen one fin slot last night and just forced the fin through. The aft CR will push it back where it belongs once I wedge that in.

Stability wasn't the issue with mine; it went horizontal on an H242, a motor that should have sent it straight up with a short, fast boost. The flight patterns between the H242 and a later flight with an I211 [I flew it again in case the first time was just a fluke] were nearly identical, indicating to me that I wasn't careful enough about getting the fins on straight.

Ok, now you got me nervous as I aligned the fins by eyeballing again. The fins are very long, so I can easily see where a warped one could cause some pretty serious problems.

What I'd recommend is getting a straight-edge, or even better, an angle bracket [I use one of those clear plastic staircase carpet holders that you nail down to the edge of each step], to check how straight the fin is.

Kerm, March makes a good point...some type of tool is good to have for checking fin alignment. I bought a piece of 1" x 1" "L" shaped aluminum at Lowes or Home Depot, can't remember which one. I use it because you can clamp to it when gluing in the fins to make sure they remain straight. Also, putting the top of the "V" down makes for a nice tool to mark lug or button locations, as the bracket tends to center itself.

Carl

Already got one. I've only used it for marking the tube so far, though. The Sentinel does come with a handy-dandy fin alignment guide printed on a full sheet of paper. When I say I eyeballed it, I mean I taped the fin alignment guide to the back of a clear acrylic clipboard I have, tacked the fins, set the BT on the clipboard and eyeballed the alignment to the guide.

I never thought to use the angle iron to align the fin. I guess I always figured it wouldn't work with the round tube. I'll give that a shot on the next one.

Here's a pic of glassing the fins. Carl may not want to look as the mess may cause his heart to stop cold.

Another view of the glassing. In the background is the coupler with the baffle drilled out for the zipperless design. I tried to cut out as much of the mess as possible for Carl's health, as I know he won't be able to refrain from looking at a pic.

Very nice Kermie...

Your idea of messy and mine are a bit different as that looks pretty clean to me.

That's why the pictures are cropped. The rest of the area looks like a tornado hit it.

Here's the coupler/baffle unit. Since it's a considerable length up the BT, I really don't need to redirect the ejection gasses. This is the same design (with more holes) that I used in the Black Brant X and it works flawlessly in that one, so I'm not quite as nervous about it. Sorry about the picture quality. I had to get close enough that the flash does more harm than good, so I had to edit it.

Well, if anyone's still checkin' in on this, I finished the fillets tonight (pics on that later). Due to the zipperless design, the top half of the recovery attaches to the nose cone instead of to a bulkhead. This kinda sucks, as the opening at the bottom of the nose cone is bigger than the eye bolt. So, I cut a hole in the shoulder of the cone and put a nut in there to screw the eye bolt in. Put a washer on the eye bolt and voila! I then poured a puddle of epoxy in over the nut to make sure nothing was going anywhere. Pic is of the nut in there before the epoxy went in.

Here's another one. 3rd coat of primer, this one Krylon white. A couple more to go, as you can still barely see the weave if you get right up to it.

My package today was decals. Fantastic looking Green Bay Packer vinyl decals. Thanks a million Jase!! Of course, being one of the world's greatest adherents to Murphy's law, the humidity here is 69%, so I can't paint my finishing coat. @(#$&#!!!!

As soon as I get this painted and the decals applied, I'll post pics. Looking good for launch on the 13th, provided the weather cooperates.

great job Kermie...
The fins do look a little small for the Binder Setenial,


more pics

Kermie,

Looks good so far. I've never seen a Binder Sentinel kit. The fin design is very interesting. I like the job you did with the glassing. I just wish that stuff was easier to come across. (ie - on the shelf of your local hardware store) I'm looking forward to seeing the finished product, even though I'm a Bucs fan.

Got the forward half of the rocket done and decals applied.

Dude!! That looks awesome!!

Now make sure your recovery protects it better than the front line protects Favre!

It's those gorgeous decals that make it look good, bro! And I hope to have the recovery do so. Favre is invincible...I'm not sure about this finish. Hey Sand, if ya see this...how long does Future floor polish have to dry?

Kerm... looks good so far. Can't wait to see it on Sunday if the weather is good. Remember I'll be the guy wearing the BEARS shirt...Marty

Kerm...great pic and theme!!! Well, I just have one question...

DID IT FLY YET???!!!

...and if no...Why Not!?

Looks great bro,

Carl

Kerm,

Future shouldn't take more than a 1/2 hour to dry.

sandman

Finally, it's done! It's not as perfect as something the Tulanko or the Sandman would pull off, but it's a definite improvement over my first HPR bird.

Weather permitting, it will fly on Sunday.