7.5" LOC DOORKNOB Level 2 Build Thread

[AcadiaRockets]

If you google LOC 7.5" V2 builds, your Doorknob build thread is at the top of the page. Why was I looking up LOC 7.5" V2 builds you ask? Well I succumbed to Wildman's LOC sale today.
Considering how close those two rockets are I will have questions.

 

[pathtouch]

If you google LOC 7.5" V2 builds, your Doorknob build thread is at the top of the page. Why was I looking up LOC 7.5" V2 builds you ask? Well I succumbed to Wildman's LOC sale today.
Considering how close those two rockets are I will have questions.

Hahaha atta boy!
I was also tempted Monday but one 7.5” cardboard rocket is enough for my fleet at the moment.

Hit me up with any questions.

 

[pathtouch]

Sent this up on an L1090 over the weekend. Made it a little over 4,500 feet. Advice to anyone that wants it, double check your biggest motor case can fit in the booster section before securing that AV bay. I had to hastily add 2.5” to the switch band to gain enough room for the 54/2800 case!

My goal was to fly an L and the L1090 was the most impulse I could fit in my current hardware. That’s only a 7% L so might be time to look at 75mm gear.

Also I modded the nose cone with a bulkhead to put my tracker up there and seems it pulled out a touch so I need to find a better way to secure that. Seems epoxy and nose cone plastic aren’t playing well.

Made a video of the flight per usual.

 

[Tim51]

Cool flight - thanks for posting. I secure the bulkheads in larger nosecones with a combination of epoxy and small machine screws placed evenly around the circumference (iirc the ones pictured are M2.5). The first 5.5" NC I modded had a considerable amount of ballast, so I was concerned about the forces exerted on that bulkhead joint. Reinforcing with screws has kept things in place over many flights.

 

[dr wogz]

that was a cool flight! happy I saw it in person (and in the various pieces at the field)

 

[happyhaplo]

Love this thread, thanks for making it.

 

[Sterk03]

Hello, I recently bought the Doorknob and yes there are no instructions with it. Not to be stupid but there seem to be parts included that are not adding up. It seems like a tube that could be a ebay with two bulkheads. Ok but then how is it secured in the large tube holding the motor or the much smaller upper body tube as diameters will not work? I know no instructions because most do their own design. So the upper body tube is usually joined with the upper body tube and then the nose cone would then need a bulkhead for the chute attachment. I see maybe one part of the bulkhead but that is it and my concern like previously mentioned is how to attach the bulkhead so it is secure with the plastic as I don't believe any further hardware is included. Any pics of how everyone has finished the Doorknob would be greatly appreciated.
Thanks
Sterk03

 

[rfjustin]

Hello, I recently bought the Doorknob and yes there are no instructions with it. Not to be stupid but there seem to be parts included that are not adding up. It seems like a tube that could be a ebay with two bulkheads. Ok but then how is it secured in the large tube holding the motor or the much smaller upper body tube as diameters will not work? I know no instructions because most do their own design. So the upper body tube is usually joined with the upper body tube and then the nose cone would then need a bulkhead for the chute attachment. I see maybe one part of the bulkhead but that is it and my concern like previously mentioned is how to attach the bulkhead so it is secure with the plastic as I don't believe any further hardware is included. Any pics of how everyone has finished the Doorknob would be greatly appreciated.
Thanks
Sterk03

https://cdn.shopify.com/s/files/1/0568/7489/3503/files/55-75-Short-Ebay1.pdf?v=1703268120

 

[Tractionengines]

Hello, I recently bought the Doorknob and yes there are no instructions with it. Not to be stupid but there seem to be parts included that are not adding up. It seems like a tube that could be a ebay with two bulkheads. Ok but then how is it secured in the large tube holding the motor or the much smaller upper body tube as diameters will not work? I know no instructions because most do their own design. So the upper body tube is usually joined with the upper body tube and then the nose cone would then need a bulkhead for the chute attachment. I see maybe one part of the bulkhead but that is it and my concern like previously mentioned is how to attach the bulkhead so it is secure with the plastic as I don't believe any further hardware is included. Any pics of how everyone has finished the Doorknob would be greatly appreciated.
Thanks
Sterk03

Can you post photos of you kit parts? LOC makes changes to their kits and sometimes the SIM files, and website photos, and directions (What there are of instructions) are not up to date with current kit parts...

Guessing without seeing the parts. I would say your rings and tubes are either the MMAS (Modular Motor Adapter System) or Adjustable Nose Weight System. ( NOT AV bay parts. That would have a sled, and threaded rods, and u-bolts, etc.)

https://locprecision.com/products/modular-motor-adaptor-for-7-5-kits?variant=39778648916159

https://locprecision.com/products/rnws?_pos=2&_psq=nosew&_ss=e&_v=1.0

 

[samb]

I started a reply before @Tractionengines that basically says the same thing. The latest and greatest version of this kit has a 12 inch airframe extension with coupler and bulkhead. A 5.5 inch diameter tube and centering rings for the Modular Motor Adapter System. And a 54mm diameter motor tube and rings to center that into the 5.5 inch tube. Ok so far ? The Doorknob page on the LOC site has a link to a nice YouTube video that gives a pretty good account of the parts. He does show an optional cluster motor mount that could be switched using the MMA system. Unless you bought the additional nose weight and/or the electronics bay kits that should do it. Hope this helps.

https://locprecision.com/collections/rockets-7-675-diameter/products/doorknob



[edit] full disclosure: I built an older version of this kit years ago that didn't have the airframe extension and modular motor adaptor goodness.

 

[Sterk03]

Thanks for the info. I am on the road so I will check when home. It is not for the MMAS system I am familiar with that. My guess is with the extended body tube upper that it has to be a bulkhead for the nose cone. That would change thou if the upper body tube is connected to the nose cone and the other end is where the bulkhead is attached vs the plastic nose cone which is not the best for attaching a bulkhead. I was told that everyone builds it differently and so no true instructions or options are not included. Not everyone will use the upper body with dual deploy or a longer total body tube.

Thanks

Sterk03

 

[samb]

@Sterk03 I think that the parts in the kit build into a motor deploy rocket with a payload section of questionable utility. The bulkhead with pre-drilled hole for the eyebolt gets glued to one end of the coupler ( I’m assuming the bulkhead diameter matches the i.d. of the coupler). The coupler gets glued halfway up into the short airframe section. Finally the nose cone is fastened in some non-permanent fashion with screws or rivets at the other end. Anyway that’s how I see the stock kit going together.

 

[Sterk03]

@Sterk03 I think that the parts in the kit build into a motor deploy rocket with a payload section of questionable utility. The bulkhead with pre-drilled hole for the eyebolt gets glued to one end of the coupler ( I’m assuming the bulkhead diameter matches the i.d. of the coupler). The coupler gets glued halfway up into the short airframe section. Finally the nose cone is fastened in some non-permanent fashion with screws or rivets at the other end. Anyway that’s how I see the stock kit going together.

 

[Sterk03]

I see that also. I also think one bulkhead fits in the shoulder of the nosecone ant the upper body tube just extends the rocket main body higher as not room or parts for an av bay but need to check the fitting of coupler bulkhead. Just have not much time to sort of sort out all bulkheads. Thanks for your help.
Sterk03