Level 1 Build: LOC Shadowhawk

Following the KISS approach here as this should be my level 1 rocket so this might be a bit tame. I've yet to see a build thread for this kit and to be perfectly honest I'll have some, probably daft, questions.

I'm pretty much building this standard with a couple of minor changes that make sense to me.


Checking parts, I did a dry fit here but didn't take a picture.



Next job was filling spirals and sanding, I was expecting a lot of sanding but even then there was more sanding than I thought possible.


I used car body putty, it bonded well and pretty quickly. The darker spirals are actually flat (they're under the top layer of paper) so should easily cover when the primer goes on. I was quite pleased with the outcome.


The changes I have decided on all revolve around centering rings. Firstly LOC suggest a masking tape wrap is sufficient for aft retention but I'm not convinced so I added a 38mm rear retainer. This one is anodised red to go with the final paint scheme. I also added an eye bolt to the forward ring for shockcord attachment, it seems more reassuring than the suggested epoxy, tape and string.


To apply internal fillets I didn't glue the rear centering ring to the mmt, however, I did add another just above the fins to keep everything in place. This seemed safer than accidentally glueing the aft ring in too soon!


I rounded the leading and trailing edges and attached the fins. While this was being completed I also glued a second eyebolt into the bulkhead and the bulkhead into the connector tube.


Some Questions:

I've decided to stick with the launch lug provided, LOC suggest cutting it at an angle and attaching about 6 inches from the aft end. I think I should cut it in half (at an angle) and put one half there and the other half at the CG. Any comments?

I intend to use the payload bay at some point so want to maintain access. My plan is to use screws to hold the nose cone on, what size should I use and how many?

I think I need vent holes to prevent unplanned early deployment. Does 1/4 inch diameter 1 just below the nose cone shoulder and one just below the bulkhead sound right? OR sims to between 1400 and 3900 feet on engines I'm likely to use.

I build the LOC-IV for my level 1. No payload. I would use plastic rivets to hold the NC on. I also split my guide tubes and mounted them similar to what you are talking about. As far as vent hole, an 1/8" will suffice. That's what I use on all my 3 & 4" rockets.

Good luck with the build and be sure to post some pics when it's finished!

Swirly said:

Some Questions:

I've decided to stick with the launch lug provided, LOC suggest cutting it at an angle and attaching about 6 inches from the aft end. I think I should cut it in half (at an angle) and put one half there and the other half at the CG. Any comments?

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I would go with rail buttons. You get a cleaner, straighter launch that way. If it's breezy on the day of your cert flight, you don't want to have to postpone it because of rod whip.

Swirly said:

I intend to use the payload bay at some point so want to maintain access. My plan is to use screws to hold the nose cone on, what size should I use and how many?

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If you mean using screws as sheer pins, #2-56 and probably two will suffice. Unless I'm missing something, if you use plastic rivets, you don't get any parachute deployment and you are launching an unguided missile.

Swirly said:

I think I need vent holes to prevent unplanned early deployment. Does 1/4 inch diameter 1 just below the nose cone shoulder and one just below the bulkhead sound right? OR sims to between 1400 and 3900 feet on engines I'm likely to use.

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One 1/8" hole just below the nose cone shoulder should do for a rocket that size, I think. For a cardboard rocket that size, you could easily get away with friction-fitting the nose cone with masking tape.

Parachute is deployed from booster section, not the NC on that kit.

I would also advise rail buttons. 1/4" is definitely large enough for vent holes I normally go for a maximum of 5mm but in your case I think 3mm is fine.
Looking forward to the seeing the build progress.

+1 on the rail buttons or rail guides.

The vent hole could be a small as 1/16". I never used a vent hole until I got to 4" diameters with 24" or longer tubes, but I friction fit the separation joint where I can pick the rocket up and give it a shake without it coming apart more than a 1/4" or less. I can't say I've ever had an issue with pressure separation.

As for attaching the nose cone, a tight friction fit, a wrap of the right color electrical tape over the joint, or two #6 metal screws would all work. If you use the screws or the tape, kind of depends on the size and strength of the ejection charge. If you are using AT reload where you can put only enough powder in, tape might be best, if you're using CTI where the charge is already sealed in, the screws might be better. It depends on how hard the payload and nose cone hit the end of the shock cord. BTW, you might want to keep the charge low so the eye bolts don't open over time.

Thanks for the advice everyone. I'll go with rail buttons as that seems to be the consensus.

As mentioned above by others, the parachute is below the payload bay/nosecone so what I'm trying to avoid is losing the nosecone during separation.

Handeman, I'll be using CTI Pro38 so not much I can do about charge size AFAIK. At some point I'll probably throw an altimeter in the payload bay, to check sim accuracy if nothing else, so I'll need a hole for that anyway. Thanks for the advice on sizing, smaller will be easier to hide in the paint.

Simon, I need to join UKRA but can't work out from the webiste if I need to print the form and sign it before sending it to you or if I can just do it electronically and email it?

You can also use BOTH rail buttons and lugs --- just put them on different sides of the rocket. That way you can fly off any available equipment. But if you'd like to pick just one option, I'd go with the rail buttons (or conformal rail guides, which is what I like).

Swirly said:

Thanks for the advice everyone. I'll go with rail buttons as that seems to be the consensus.

As mentioned above by others, the parachute is below the payload bay/nosecone so what I'm trying to avoid is losing the nosecone during separation.

Handeman, I'll be using CTI Pro38 so not much I can do about charge size AFAIK. At some point I'll probably throw an altimeter in the payload bay, to check sim accuracy if nothing else, so I'll need a hole for that anyway. Thanks for the advice on sizing, smaller will be easier to hide in the paint.

Simon, I need to join UKRA but can't work out from the webiste if I need to print the form and sign it before sending it to you or if I can just do it electronically and email it?

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You can do the whole thing electronically, we'll raise a paypal invoice for you.

As far as the nosecone goes I have a PML D-Region Tomahawk that I have launched countless times on H and I motors with single deploy motor ejection and the av bay in place. To keep the nosecone on I put masking tape around it and friction fit it hard in there. It hasn't failed once. For double protection you could even put a redundant shock cord from the top of the bay to the nosecone.

External fillets completed, it took most of last week doing 2 a day using 30 minute epoxy with fibreglass micro beads, this makes a massive difference when sanding afterwards.

Naked Rocket.


Then into painting, fortunately the weather has been decent today, for non-UK folk this was a 3 day weekend and today was the only day with no rain/wind and was actually pretty warm too. Managed to get the primer done this morning and the first colour coats this afternoon.

After primer (masking tape preventing it sticking together straight!)




Masking for the first colour. Tamiya yellow masking tape is expensive but the first time I used it it was a revelation. I expect no bleeding at all which will be essential with the plan for the payload bay paint scheme.





As for the fixing the nosecone I decided to use the redundant shock cord mount inside the payload bay and put the nosecone on a second shockcord. Hopefully it won't be needed but it should make it impossible to lose and provide somewhere to attach a beeper if the crops have got up.

Finished and ready to launch. Although I'm not exactly sure when that will be as I suddenly have to buy a house:shock: This was my first attempt at a checkerboard, it's not perfect but from pad distance it should look OK. I wanted a colourscheme that would be visible against blue and grey skies, I think this one does the job.

Also I'm not sure why these pictures have decided to rotate 90 degrees, they're the right way up on my computer/phone. Unless someone can give me a clue on how to rotate them back you'll have to tilt your head!



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Swirly said:

This was my first attempt at a checkerboard, it's not perfect but from pad distance it should look OK.

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How did you mask the checkerboard? I can see doing a lot of cutting of the tape which might be what you did, but if there's an easier way, I'l love to hear about it.

Handeman said:

How did you mask the checkerboard? I can see doing a lot of cutting of the tape which might be what you did, but if there's an easier way, I'l love to hear about it.

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I second that request. I've never tried to mask a checkerboard or other roll pattern, because I wasn't sure how to go about it.

Nice looking rocket!


TA

No easier way that I know. It's 14x14 so I cut 98 squares and stuck them on. Got a photo somewhere, it was fairly mind sapping.

Swirly said:

No easier way that I know. It's 14x14 so I cut 98 squares and stuck them on. Got a photo somewhere, it was fairly mind sapping.

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That's what I was afraid of.......