LOC DOORKNOB Arrived

My Birthday present has arrived - great to have a wife that supports the hobby!

So, introducing the newest member of my family is this fresh out of the box LOC Doorknob. Its a beauty!!!

As you can see on the parts pile, I also picked up an 54mm Aeropack motor retainer as well as a 52" Sky Angle parachute. I'll use the included tubular nylon shock cord, its good quality. I've also got a nice stainless u-bolt and some 800lb quick links in the garage ready to go. That 54mm MMT is almost as big as some of my smaller rockets. I have used the fin-lock system before and I really liked it.

Unfortunately I'll be out of town this weekend and can't play with my new toy. The following weekend I'll get my stand out of the shed and mount the airframe on it so I can fiberglass it. After peeling off the glassine layer, I'll apply 2x wraps of 5.8oz S-glass and 1x veil layer of 1.48oz deck cloth followed by some Teflon peel ply. Then after the fins are on and filleted, I'll apply a tip to tip with one layer 5.8oz S-glass and one 3.08oz e-glass and more Teflon peel ply. The Teflon leaves an awesome surface, bleeds off a bit of extra epoxy, and saves tons of time sanding later. I've been using this formula lately, and its worked out well. I know glassing adds some weight, but its motor ejection and I'm not looking to break any altitude records.

I'll be using West Systems epoxy for the entire build, 105 resin and 206 slow hardener. For the fillets, I squirt one pump of resin and hardener (stir quickly for 1 minute) and then mix in a heaping spoon of 404 high density filler and one heaping spoon of 406 colloidal silica. This allows a smooth, non-running fillet to be formed in and easily shaped with the back of a plastic spoon. I'll keep a tally of the weights before and after things are added during the build. The glass added about 40oz of extra weight to my LOC Bruiser (2 sections), so for this one section airframe I'm going to guess about 27oz.

I'm still up in the air on the final paintjob, so I'm accepting suggestions! My goal is to have it ready to fly for the November TTRA launch in Plant City, FL.

Sweet! Congrats! I've considered this rocket before... looks like a fun build!



Later!

--Coop

There was an old Daffy Duck cartoon where Daffy played the part of a travelling salesman trying to sell various items to an increasingly angry homeowner. Toward the end, he tries to sell the man a cigarette lighter that doesn't work. Daffy walks out the door dejected. The homeowner continues to try to light the lighter, not realizing that the leaking gas on the stove was gradually filling the home. Daffy turns and says, "There must be something I can sell this man. He grabs the doorknob to go back in the house. At that moment, the lighter finally ignites, the house explodes leaving nothing but the doorknob in Daffy's hand. Daffy screams, "I got it now! I got it now! Hey Mister! You need a house to go with this doorknob!"

Paint the rocket in a Looney Tunes theme, featuring Daffy Duck.

I really would like to build that rocket. I want wanted it ever since I built the Minie Magg.

I've been really horrible about keeping up the progress on this rocket. Its coming along nicely! The airframe was too long for my stand, so I had to use a long cardboard tube to suspend it between two garbage cans.

Picture 1: Glassine was peeled off so the epoxy would soak in better. I didn't wince once doing it, when I built my LOC Bruiser I cringed ripping into a brand new body tube.

Picture 2: Body tube mounted, glass cloth getting measured out.

Picture 3: Ready to go, epoxy getting mixed up.

Picture 4: Fiberglass has been applied (and cured for 3+ hours), I had just pulled off the Teflon peel ply and was about to trim off the overhang and open up the fin slots while the epoxy was still "green" and easily cut with an exacto knife.

Picture 5: You can see a few inches of one end of the tube is still "shiny" where I didn't apply the Teflon. The Teflon roll was too short to fully cover the airframe, but I'll be doing tip to tip fiberglass on the fins and wasn't real concerned about the the finish at this stage. I'll use the peel ply on the final layer to get that near perfect, ready to sand finish.

Lessons Learned #1: The 1.45oz fibergloss cloth I had used as a veil layer is VERY prone to "wrinkling". I wasted alot of time straightening it. At one point I almost gave up and ripped it off. I'll probably stick with 3oz fiberglass as a veil next time, its stiff enough not to wrinkle. Or I won't use a veil, the teflon seems to leave a really good finish and I'm not sure I actually need it.

Lessons Learned #2: Be careful the whole assembly doesn't slide off the trash cans and hit the floor. Mine did as I was rolling on the glass, the cardboard tube I mounted the assembly on crept along the top of the can with every turn until it fell off. No harm done, thankfully.

I've since sanded the body tube smooth and mounted the fins using the fin-loc. I then epoxied in the centering rings and mounted the 54mm MMT. I'll JB Weld the Aeropack motor retainer tonight. More pictures to come!!

I'm having so much fun with this build that I ordered a LOC Warlock today from Wildman. I love those big fat LOC 7.5" kits!!!

Awesome! Are you doing stock paint, or planning something different?

loopy said:

Awesome! Are you doing stock paint, or planning something different?

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Why its funny you should ask, I was just on my lunch break working on the final paint scheme.

What do you think? I'll paint my smaller rockets "stock", but I like to customize the bigger ones.

The build is pretty far along, last night I mounted the Aeropack retainer. Later this week/weekend I'll get the fin fillets completed and then tip to tip the fins with some glass. After that, final sanding and ready for primer.

That is awesome!!! I like that alot! Are you painting the logo, or having it done with vinyl?

neond7 said:

I'm having so much fun with this build that I ordered a LOC Diablo today from Wildman. I love those big fat LOC 7.5" kits!!!

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LOC Diablo? Never heard of it, nor could I find it on Wildman's site. Need more info. I also like LOC's fat stubby rockets!
-Ken

new2hpr said:

LOC Diablo? Never heard of it, nor could I find it on Wildman's site. Need more info. I also like LOC's fat stubby rockets!
-Ken

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I bet he ment to say Warlock

bill2654 said:

I bet he ment to say Warlock

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Oops, you are correct, I had ordered the Warlock. Good catch......

loopy said:

That is awesome!!! I like that alot! Are you painting the logo, or having it done with vinyl?

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Vinyl of course, I can't even draw a straight line, much less paint curvy letters. Stickershock to the rescue!!!

Finally downloaded more pictures off the camera. Onward!

Picture 1: The body tube got a good once over with the orbital sander, 150 grit pad. Still a few wrinkles from the veil layer I'll knock down more later.

Picture 2: The dremmel works great for opening up the fin slots. Test fit a fin in each slot.

Picture 3: I slightly beveled one edge of the fin lock - makes it MUCH easier to insert into the slot in the fin. Because the fiberglass added some diameter to the body, I used the dremmel to make the slot in the fin a bit wider toward the bottom of the fin root so I could get the tab inserted.

Picture 4: The first fin was locked in.

Picture 5: The fin tabs "warp" the body slightly out of round, which you can see in the picture. Not sure if the fiberglass on the body tube makes it worse. It makes it a real pain to get the rear centering ring installed!!! Its goes back to round after the CR is in.

And more progress:

Picture 1: All fins locked in and ready to go. Finally looks like a rocket.

Picture 2: I test fit the rear centering ring and was happy to see the motor retainer is slightly recessed. So much easier to have a rocket that sits flush with the ground, my LOC Bruiser's retainer sticks out a bit and I have to lean it on something so it doesn't fall over.

Picture 3: I removed the rear CR and applied epoxy fillets to the fin tabs/locks. I found a 50/50 blend of West colloidal silica and West high density filler works best, won't run or sag. You can see the line I drew to mark the top edge of the centering ring.

Picture 4: Rotated the tube and got the last fin root filleted.

Picture 5: I bought a stainless steel u-bolt for the front CR. I didn't trust an eye bolt for a bird this big/heavy. I used 30 minute epoxy to coat the threads and the entire back of the mechanism so it isn't going anywhere.

More to come......

I'll be doing fillets today. Pictures to come shortly.

As an added bonus, FedEx showed up this morning and dropped off the Warlock that I had ordered from the Wildman. Fast shipping, love those Wildman club prices.

Hay Jeff The doorknob looks cool. What will you be sending it up on.

Getmore said:

Hay Jeff The doorknob looks cool. What will you be sending it up on.

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It should be ready for November - first flight I'll use a I327 DarkMatter. And if the weather is good, I'll follow it up with a J350.

neond7 said:

It should be ready for November - first flight I'll use a I327 DarkMatter. And if the weather is good, I'll follow it up with a J350.

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Hey Jeff - - looking good! I hope to see the maiden launch in November.

Chris - thank you!

After a lazy, rainy day I finally got the first set of fillets applied. I had hoped to get them all done today, but that didn't happen. Hopefully I'll be more motivated tomorrow. My goal is still to start the tip to tip fiberglass on the fins Monday (love those Federal holidays!!!).

I did use blue painters tape when I applied the fillets, but I had epoxy on my gloves and didn't want to handle the camera to get a picture. I pulled the tape, removed the gloves, and snapped the pics.

Usually I bevel the front of the fins before I apply the fillets...... oops. I'll do it tomorrow.

Those fillets look very nice. Your Doorknob looks straight as an arrow, great job.

I finished the final set of tip to tip fiberglass on the fins last night. Looking forward to sanding, primer, and paint.

In the second picture I had already removed the teflon peel ply and trimmed off the overhang while it was still green and flexible. I didn't get any pics of the wetting out process since I had wet epoxy on my gloves and I'm sure my wife wouldn't like epoxy all over the camera.

This should be flying at the TTRA launch in November. I better hurry and order my vinyl......

I haven't posted much on this build lately, most of the pics are still on my camera but I uploaded these from my cell phone. Basically I have completed the paint job using Krylon Banner Red over Duplicolor primer. I wet sanded the first color coat and the second coat I sprayed on Sunday came out pretty good. I could keep chasing the nits, but it looks nice from 10 feet. I'll shoot the clear coat next week, I want to make sure the paint is fully cured and seal in the vinyl.

In the first pic, I was applying the vinyl - thanks Mark from Stickershock for doing such a great job!!!

In the second pic, the main graphic is on, in the third pic the bands are just taped on and are still on the transfer paper. The final bands will be a bit thinner.

Looking forward to flying it November 17th with the Tampa TTRA group!! It should fly nice on an I327DM.

Its been a fun build for sure. Good thing I'm getting this one off my bench, as my LOC Big Nuke 3E (modified for a 54mm MMT) will be arriving via FedEx tomorrow.

Are you sure he wasn't an insurance agent? "during a hail storm 4PM on the 4th of July" 1 black eye..... 1 million dollar policy?
"Daffy Duck and Porky Pig - Fool Coverage"

https://youtu.be/DcMFsgA9iPo

JD

EeebeeE said:

There was an old Daffy Duck cartoon where Daffy played the part of a travelling salesman trying to sell various items to an increasingly angry homeowner. Toward the end, he tries to sell the man a cigarette lighter that doesn't work. Daffy walks out the door dejected. The homeowner continues to try to light the lighter, not realizing that the leaking gas on the stove was gradually filling the home. Daffy turns and says, "There must be something I can sell this man. He grabs the doorknob to go back in the house. At that moment, the lighter finally ignites, the house explodes leaving nothing but the doorknob in Daffy's hand. Daffy screams, "I got it now! I got it now! Hey Mister! You need a house to go with this doorknob!"

Paint the rocket in a Looney Tunes theme, featuring Daffy Duck.

Click to expand...

neond7 said:

Looking forward to flying it November 17th with the Tampa TTRA group!! It should fly nice on an I327DM.

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Looks good Jeff - Just curious, how much does it weigh and what is the predicited altitude on the I327DM. It should be a cool flight!

Looking good Jeff. See you in November. I might do my first duel deploy on a J275 well see.

It came out great and its built like a tank, awesome job like always!

csoechtig said:

Looks good Jeff - Just curious, how much does it weigh and what is the predicited altitude on the I327DM. It should be a cool flight!

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Chris,
Using the stock RockSim file for this kit, I get the following:

I327DM - 1352ft apogee
J420R - 1722 ft apogee
J350 - 1726ft apogee

I know building heavy added some weight to the stock kit, I will install the recovery equipment this weekend when I have time and weigh it again. I guess I add the extra weight to the body tube? That is were most of the weight was added via fiberglass and epoxy.

Now that I'm looking at the data, once the extra weight is added to the simulation, it will bring down the altitude estimates. The I327 might not be enough for it, I would like to at least get it over 1,000' to allow enough time for the recovery equipment to fully deploy. The J420R will be fine, I thought it would be appropriate to use a "red" motor on this bright red rocket. So that might be the go-to motor for the first flight. I'll also use a bright red Dr. Rockets motor case to really keep with the theme.

And just for kicks, I also ran a simulation using a K456DM. It would reach 3317', which is way more of a walk than I'm willing to do with motor ejection!

Oh, and the stability came out to .88 cal with the J420. I'll check it again with the final weights. If it stays around this number, I assume I'll need to add a little nose weight?? 6 ounces in the nose pushes it up to 1.1 cal.

neond7 said:

I guess I add the extra weight to the body tube? That is were most of the weight was added via fiberglass and epoxy.

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It really doesn't matter 'where' you add the weight on the RockSim design as long as it gives you the appropriate Center of Gravity. Here's what I do after every build...

1. Pack everything (minus the Motor & Case)
2. Weigh rocket
3. Figure out Center of Gravity
4. Go into your RockSim File and add a 'mass component' to calibrate the exact weight.
5. Most importantly - shift the mass component forward (or aft) to reach the exact Center of Gravity. You can literally narrow the mass component to 0" and have a straight line up & down through the rocket design.

Then, the program is pretty accurate with estimated weight of various motors and CG/CP calibration. Considering the diameter and Tip to Tip FG finish, you might want to go exclusively with J motors in that bad boy.

I look forward to seeing it fly!

I think you should fly a can of Coke in the nosecone and drink it upon retrieval.

Mason,
I'll let you open the can first after the flight. :y: