L2 Build - Binder Excel Plus - Success

Four day holiday weekend and had a big box from Binder Design show up on the porch.
Sounds like a good excuse to start my Level 2 project.

Binder Design Excel Plus 38mm.

There has already been a number of build threads on this rocket here, so I won't go into a lot of detail. Plus I have really made a lot of progress, and didn't take a lot of photos.

Really great kit. Binder does an great job of packing these things and really good instructions.

First shot is the fins tacked in with epoxy.

While I had the fins tacked in, did a test fit of the airframe parts.
Full stack DD config.

Just in case I want to fly single motor deploy, this kit can be flown in the standard Excel config.

Cut out the tabs on the fin slots and removed the motor mount assy.
Then mounted the middle center ring.
I requested the longer motor tube and third centering ring when I placed the order. This will allow easier access to the shock cord mount.

Waiting on epoxy to set up, started on the avbay.
Coupler tubes gave me some problems, OD was larger than ID of airframe tubes.
Ended up peeling one layer of paper from the coupler tubes and sanding smooth.
Perfect fit now.
2 couplers epoxied into the avbay airframe tube.

Great kit!! Love mine - it was the first DD kit I ever built. It flies great on J350W and J340M motors.

I look forward to seeing more pics of your build. Are you going to paint it with the stock colors? Normally I go with custom colors and vinyl but the stock orange and white is really sharp looking.

Going to paint it the stock colors, kind of like the catalog paint scheme.
More pics to follow. Waiting on the Aeropack retainer now to finish up the motor mount, will move on to the avbay this week. Already have the Stratologger and all the parts needed to complete that part.

I have been enjoying your build threads on the LOC kits. But you need to get back on that 5.5 Horizon build

neond7 said:

Great kit!! Love mine - it was the first DD kit I ever built. It flies great on J350W and J340M motors.

I look forward to seeing more pics of your build. Are you going to paint it with the stock colors? Normally I go with custom colors and vinyl but the stock orange and white is really sharp looking.

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Txnrcr said:

Going to paint it the stock colors, kind of like the catalog paint scheme.
More pics to follow. Waiting on the Aeropack retainer now to finish up the motor mount, will move on to the avbay this week. Already have the Stratologger and all the parts needed to complete that part.

I have been enjoying your build threads on the LOC kits. But you need to get back on that 5.5 Horizon build

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Great choice on the Stratologger - I've had 100% successful deployments with mine. On 5.5" rockets I use a second one for backup, although its never been necessary its nice to know its there "just in case". I set the delay on the backup to apogee +1 second and the main at 600 ft (primary is set for 700).

Also a great choice on the Aeropack, I put one on all my builds. They aren't cheap, but they are really nice and make motor changes a snap. Have you considered blast caps for your av-bay? I also recommend the wiring kits from Doghouse rocketry, the kit has everything you need and includes a rotary switch. I picked up a cheap soldering iron and some shrink tube at Home Depot for $20 something and change and have done a decent soldering job on the wires to the switch (IMHO).

Glad you have been enjoying my builds, they have been lots of fun in spite of the heat. I'm probably going to start back on the Horizon build soon after the LOC Magnum is finished - I have a few design decisions to make that will affect the rest of the build so I'm stewing on a few ideas. My plan is to go way overboard on every detail, I want to earn my L3 on the first attempt. In the meantime, I'm soldering on with the LOC builds - my wife wants them both finished so I can park back in the garage for awhile..... :y:

Great job on your build so far, and you did the right thing getting the longer motor tube like I did on mine. Mike Fisher at Binder Design is a great guy to work with, and puts out some nice kits. So far I've built two JackHammers, a Bat, and the DD Excel. I also used his "custom" shop to order some fin sets and tubes for two scratch built designs I came up with.

neond7 said:

Have you considered blast caps for your av-bay? I also recommend the wiring kits from Doghouse rocketry, the kit has everything you need and includes a rotary switch.

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Yes, got the wiring kit from Doghouse. Also picked up some of their ejection canisters to try out. Plastic instead of the aluminum from Blast Cap, but seem up to the task.

Compared to the 3" avbay I am building for my Horizon, this thing is huge. All sorts of room to mount stuff.

I know you'll have a lot of fun with this rocket. Great build.

I'm thinking you'll probably want to get the 54mm kit also. 38mm is good for L1 and the baby Js, but you'll want to get a 54mm or 75mm when the Ks and Ls start calling.

Handeman said:

I know you'll have a lot of fun with this rocket. Great build.

I'm thinking you'll probably want to get the 54mm kit also. 38mm is good for L1 and the baby Js, but you'll want to get a 54mm or 75mm when the Ks and Ls start calling.

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I've got the 54mm MMT in mine, although I haven't used anything bigger than a "J" yet. I wouldn't hesitate to throw a K456DM in it on a nice low-wind day, but anything bigger might be pushing it without any composite reinforcement.

And an "L" motor?? You were kidding, right? :y:

neond7 said:

I've got the 54mm MMT in mine, although I haven't used anything bigger than a "J" yet. I wouldn't hesitate to throw a K456DM in it on a nice low-wind day, but anything bigger might be pushing it without any composite reinforcement.

And an "L" motor?? You were kidding, right? :y:

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Of course not!. I build my L2 cert rocket with a 54mm MMT and the first flight was a K695R to 6,428 ft. I used a lot of 38mm J motors after that, but eventually a CTI Pro54 6GXL L935-p IMAX had to be flown. I was actually a little disappointed with it. I was looking for +10,000 ft and +1.2 Mach. I got the 1.2 Mach, but only got 9,595 ft. I still need to hit 10K so I guess another rocket is in the works. The next one will be a L2, but with a 75mm MMT so I can stuff enough in it to top 10K. Of course a MD 54mm would do the same thing, but I have the 4" fiberglass tubes for the new one.

Back to work, so the build slowed down.
Mounted the top center ring and now adding the epoxy fillets to the fin can.

Got a few parts in the mail box today - 38mm Aeropack, plastic rivets, and sheer pins.

Txnrcr said:

Got a few parts in the mail box today - 38mm Aeropack, plastic rivets, and sheer pins.

View attachment 137645

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If you start getting more DD rockets, you can get these parts in bulk MUCH cheaper from McMaster Carr. I've got about 8 DD rockets, and I go through lots of rivets and shear pins.......

Here are the part numbers of what I use:

91020A218 Nylon Click-lock Shank Rivet, .163" Hole Dia, .177"-.217" Material Thk, Black

94609A081 Nylon Round Head Slotted Machine Screw, 2-56 Thread, 1/2" Length

neond7 said:

If you start getting more DD rockets, you can get these parts in bulk MUCH cheaper from McMaster Carr. I've got about 8 DD rockets, and I go through lots of rivets and shear pins.......

Here are the part numbers of what I use:

91020A218 Nylon Click-lock Shank Rivet, .163" Hole Dia, .177"-.217" Material Thk, Black

94609A081 Nylon Round Head Slotted Machine Screw, 2-56 Thread, 1/2" Length

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Been looking for those parts #'s! Thanks Jeff! <$10 for 50 rivets! Cool! Building a Mcmaster order..LOL

More progress, installed the 38mm Aeropack retainer and let it set up overnight.
Fin can assy completed and ready for installation in BT.
Fin can installed.

In the previous step of tacking the fins to the motor tube, I numbered the fin slot tabs to be removed and their locations on the airframe before cutting them out.
After installing the completed fin can, I glued these back in place to reduce the work of having to fill the holes left at the end of the airframe.

What a clean build. Looks nice, I always liked the Excels.

Got the external fin fillets done today, shown here masked off for the first pair.
Glued the avbay bulkheads together, test fit everything with the supplied hardware.

Txnrcr said:

In the previous step of tacking the fins to the motor tube, I numbered the fin slot tabs to be removed and their locations on the airframe before cutting them out.
After installing the completed fin can, I glued these back in place to reduce the work of having to fill the holes left at the end of the airframe.
View attachment 137909

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Awww, now you're just showin' off. Wait a minute... that's what a build thread is, isn't it ?!? Really, really, really great work.

Really ! :grin:

samb said:

Awww, now you're just showin' off. Wait a minute... that's what a build thread is, isn't it ?!? Really, really, really great work.

Really ! :grin:

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Definitely showing off! :wink: I know when I extend my fin slots, there aren't any nice neat tabs to glue back in.... they get mangled pretty good. You must have used an exacto knife - I use a Dremel and whip through the material in a hurry. I use thick fillets mixed with lots of filler, I always extend the fillet in a nice tapered angle to the rear and fill in and cover the spot where the tab was cut out. Either way will work, but I figure, its going to be buried under epoxy (and usually a layer of fiberglass in my case), so I don't bother.

But great work on this build, you are doing an awesome job. Pick a style of building that works for you - can't wait to see your finished pics. And flight photo and video.

Not sure if its just luck or what, but my Excel always lands within 75 ft or less of the launch pad.

Wow, almost a year since I started this build.
Put this project on the back burner over the fall / winter. Between NSCA sporting clays tournaments and my daughters new "career" as lead vocalist in a rock band, just didn't have the spare time to work on it. She's 13, no gigs without a chaperone / body gaurd - namely DAD!.

Anyway, weather is finally good for flying. Actually got a free weekend to attend a local LPR/MPR launch, re-sparked interest in the Excel.

Neond7's thread on finishing his LOC Doorknob project got me off my rear and back in the garage.

Productive weekend so far.
Finished the booster section.
Fins and thrust plate joint filled with FnF and sanded smooth.
Rail buttons installed, drogue chute compartment vent hole drilled. CA'd the top 2 inside inches of the airframe and sanded smooth.
Booster ready for filler primer and paint.

Drilled holes for altimeter sample ports (4X) and plastic rivets in the alt bay and payload tube. Soaked thin CA in holes, sanded clear of all burrs.
Reinforced coupler tubes and inside ends of payload airframe with thin CA.
Then lots of sanding for proper tube fit.

Alt power switch will be mounted on alt sled. Sampling ports are large enough for small screwdriver to operate switch (rotory 110 switch from Doghouse Rocketry).

Altimeter bay is now ready for primer / paint. Need to drill sheer pin holes and payload airframe will also be ready for primer.
Will probably do my ejection charge ground testing before painting.

I'm building the same kit aside from mine being a 54MM for my level 2 cert. rocket. I also asked for the longer motor tube extra centering. Are you setting yours up to eject the payload section for the main chute or just blow the nose cone?

Squawsach said:

I'm building the same kit aside from mine being a 54MM for my level 2 cert. rocket. I also asked for the longer motor tube extra centering. Are you setting yours up to eject the payload section for the main chute or just blow the nose cone?

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Going to blow the nose cone and all laundry through the front.
Binder shows blowing the payload tube with nose secure to tube in the instructions. I'm sure this would work fine and Binder has tested this set up extensively.

My concern was ejection charge packing chute up into the nose and not getting a good deployment / chute hung in tube.
Might be nothing to worry about, but was bothering me enough to switch to the method familiar to me. Especially on a cert flight.

JW

I will try the payload section method and report back. I have the same fear as you about stuffing the chute to the point that it binds. I'm still new to this so my fear may have no merit.

Txnrcr said:

Wow, almost a year since I started this build.

Neond7's thread on finishing his LOC Doorknob project got me off my rear and back in the garage.

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I guess I did drag out my LOC Doorknob build - only a mere eight months to glass one tube and build one avionics bay! Lol........... Good intentions, but one thing always leads to another in addition to the L3 build I was working on at the same time. I need to quit that, its a bad habit to start one before I finished the last one.

Had some great flights Saturday up in Bunnell, I was *THAT* close to flying my Excel but I had an I435 motor I had assembled in February and never used, so I took my LOC Fantom instead. I only fly my Excel on J's and between the LOC Magnum, the LOC Doorknob, The LOC Hyperloc 835, and the LOC Fantom there wasn't room for another rocket. I think I like LOC kits....sheesh.....

Squawsach said:

I will try the payload section method and report back. I have the same fear as you about stuffing the chute to the point that it binds. I'm still new to this so my fear may have no merit.

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I use sheer pins on the nose cone and blow the laundry out the front of my Excel. Use brass shims on the nose cone shoulder and the sheer pins will break cleanly. This rocket has had at least five flights on it, never any failures.