LOC DoorKnob HED DD build

[ChrisAttebery]

I'm building an LOC DoorKnob. I've always liked short stubby rockets. I built this LOC Warlok about 15 years ago and it was always fun to fly.






For the DoorKnob I'm building the airframe completely stock. I used Titebond to glue the fins and fin tabs in place. I decided to use 30 minute epoxy to glue the motor mount in place mainly because it would give me a little time to adjust the placement of the parts before the glue grabbed. All that is left on the airframe is to add a motor retainer and paint.

I want to try dual deployment on this rocket but I don't want to add any more length to it so I'm going to try Head End Deployment and a cable cutter. The altimeter bay will be built into the nose cone. Instead of cutting the entire bottom out of the nose cone I'm going to cut a 54mm hole in the bottom and glue a 4.5" centering ring inside. I'll have to cut a 4.5" by .25" slot to get the ring inside the cone. Six 10-32 screws will clamp the plastic bottom of the shoulder between the centering ring and a bulk plate. The AV Bay will be glued to the bulk plate similar to the method that John Coker documented on his web site.

I've ordered the centering rings from Nat at UpscaleCNC. I emailed the file to him yesterday and he already had them cut this morning. I like dealing with vendors that work at my pace.

 

[thobin]

I've ordered the centering rings from Nat at UpscaleCNC. I emailed the file to him yesterday and he already had them cut this morning. I like dealing with vendors that work at my pace.

Hey you realize that's not fair right!?


TA

 

[ChrisAttebery]

I could cut them on my CNC mill, but I honestly thought it would be more work than it was worth. 😉

 

[gerbs4me]

I like how you painted that rocket, looks really cool!

 

[ChrisAttebery]

The black and yellow were rattlecan paint. I cut the eyes and mouth from sign vinyl. It was a fun project and I got complements every time I flew it.


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[Kehoes23]

Can you post photos of the av bay? I have the same kit and would like to do the same thing you are doing

 

[ChrisAttebery]

Yes I will, but it will be a week or so before I can.

 

[ChrisAttebery]

The parts showed up today. Let's see if I can attach a picture:



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[ChrisAttebery]

I got the holes and slots cut into the nose cone base:


I epoxied the T nuts into the centering ring and installed the hardware on the bulk plate:



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[thobin]

That's a neat idea, it will be interesting to see the AV bay set up. What kind of glue are you going to attach the backer plate with I cant get any glue to stick to the LOC nose cones?


TA

 

[Kehoes23]

Thanks for the photos, very interesting design, can't wait to see it done.

 

[ChrisAttebery]

I'm just going to use Shoe Goo. It will stick to plastics that CA and epoxy won't. The glue only needs to keep the ring in place when I'm screwing the bulk plate in place.

That's a neat idea, it will be interesting to see the AV bay set up. What kind of glue are you going to attach the backer plate with I cant get any glue to stick to the LOC nose cones?


TA

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[thobin]

Shoe Goo I think I have some of that, I will try that, thanks.

TA

 

[ChrisAttebery]

Oh, good. Try it out and let me know if it sticks. I'm on vacation for a few days and won't get to work on it until next weekend. :^)


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[ThirstyBarbarian]

I foresee something like the Warlock or Doorknob in my rocketry future. I'm looking forward to watching the build and possibly seeing this thing fly, Chris. Do you have a particular launch in mind for the maiden flight?

 

[ChrisAttebery]

Yes, I'm hoping to fly it at TCC in August.


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[ChrisAttebery]

I glued the centering ring inside the NC with Shoe Goo this morning. Then I started working on the altimeter tray. I drew the tray up in TurboCAD then cut it out of 1/16" plywood. I've got the RRC2+ mounted and I'm working on the battery mount now. The arm will hold the Featherweight magnetic switch right next to the base of the nose cone.





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[ChrisAttebery]

I drilled 8x 3/16" vent holes in the nose cone about an inch above the shoulder. I also bolted up the bulk plate to the nose cone to make sure that I didn't have any interference from excess glue.

 

[ThirstyBarbarian]

Chris, this is an interesting thread. I've never done any kind of dual deploy or even followed a build thread involving DD very closely, so this question may be off base. I notice that one end of the slot cut for the centering ring is exposed beyond the edge of the bulk plate. Does that need to be sealed so that pressure from the ejection does not enter the NC and affect the altimeter?

 

[ChrisAttebery]

Yes, it does. The NC should be completely sealed from the parachute compartment. I filled in the slot with Shoe Goo so you just can't see it in the picture. I could have saved myself a little trouble by making the bulk plate another 1/4" larger in diameter. I'll have to remember that for the next one.

 

[ThirstyBarbarian]

Yes, it does. The NC should be completely sealed from the parachute compartment. I filled in the slot with Shoe Goo so you just can't see it in the picture. I could have saved myself a little trouble by making the bulk plate another 1/4" larger in diameter. I'll have to remember that for the next one.

That makes sense. I cannot see the seal in the photo. Shoe Goo to the rescue!

 

[ChrisAttebery]

As recommended by fox_racing_guy in his Warlock thread (https://www.rocketryforum.com/showthread.php?43428-LOC-Precision-Warlock-build&highlight=doorknob) I picked up a can of Bulldog Adhesion Promoter for the nose cone this morning. There must be gold flakes or something in it since it was $24 a can. :y:

Anyway, the nose cone is basically done so the next thing on the list is to get the rocket painted. The primer will be flying this weekend.

 

[ThirstyBarbarian]

The primer will be flying this weekend.

Cool! Have fun with it.

 

[iter]

Very neat seeing it in person today. Looking forward to the flight!

Ari.

 

[ChrisAttebery]

Thanks Ari, me too. :^)


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[iter]

BTW, the place you mentioned didn't have the tap. What was the website you said that wold it?

Ari.

 

[ChrisAttebery]

Oh no. I'll have to think about it. I'm 99% sure that's where I got mine. If you want to meet me near SJ next week I can let you borrow mine.


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[ChrisAttebery]

I started primering the beast this morning. I've used about a full can of primer so far.

 

[iter]

Oh no. I'll have to think about it. I'm 99% sure that's where I got mine. If you want to meet me near SJ next week I can let you borrow mine.

There are a lot of websites that list Harry Higley's 1/4-32 tap, but all of them say "out of stock."

Does this look like a legit part? https://www.opentip.com/product_info.php?products_id=3395578

Ari.

 

[ChrisAttebery]

Yes it does. McMaster Carr also has them in both plug and bottom versions