LOC Viper IV (build, brainstorming, and various other ramblings...)

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I only remember the nozzles sticking out the back. Don't know what caused the delayed ignition either.



What kind of harness are you getting for the RRC3?

None. I had a temporary case of blindness, and maybe stupidity. The manual mentions an AUX harness and I saw the 4-pin header on the board. So I assumed I needed a harness. I didn't see the screw terminal labeled AUX right next to the header. Silly problem solved. I'll hook the lead to my lower terminal right into the AUX terminal. One 9V battery runs the whole operation. I don't know about two starters from one battery, but Jim says that's the way to do it.
 
None. I had a temporary case of blindness, and maybe stupidity. The manual mentions an AUX harness and I saw the 4-pin header on the board. So I assumed I needed a harness. I didn't see the screw terminal labeled AUX right next to the header. Silly problem solved. I'll hook the lead to my lower terminal right into the AUX terminal. One 9V battery runs the whole operation. I don't know about two starters from one battery, but Jim says that's the way to do it.


Ahhhh, gotcha.

I was beginning to wonder if I had missed that requirement in the manual lol
 
Ahhhh, gotcha.

I was beginning to wonder if I had missed that requirement in the manual lol

Yeah, kinda what I was thinking. Grumbled and thought to myself "Why is there always an add-on...that I don't have?" Missileworks is developing a pyro expansion board but don't know if it will be available, or even needed, before my flight. Which should be February.
 
I have had a crazy schedule at work that had me getting home at 1230 so I've had some time to do a little before everyone else got home. A little epoxy here, some sanding there. Finally got enough done to do an update.

Poured a bit of foam in the voids at the aft end of the body tube to fill those things up. I knew the foam wouldn't be the finished product but it added very little weight to that part of the rocket. I taped all the parts I didn't want the foam prior to pouring then scraped/wiped excess off before it completely set.

Viper 17.jpg

A little epoxy mixed with some pigment and faring compound to cover the foam. Mixed it to where it would just self level. It's two colors because I didn't mix quite enough the first round and switched colors so I could tell where I was pouring. It self leveled nicely.

Viper 18.jpg

The bottom side of the sled that will go into my coupler. The RRC3 will sit on the other side. A 9volt will set here on this side. That's PEM nuts pushed in and epoxied in place. No the switch will not be in the center. I ran out of room fast and this was the most logical (to me) choice. It will be accessed via a hole in the payload section. That section will be riveted to the coupler, so lining up the holes won't be a big problem.

Viper 19.jpg

Lower bulkplate. This end is firmly epoxied to the rods and nuts. The squarish black thing is the DC plug that will provide power to the air starts. The plug will pull out when the sections separate. Pending ground test, probably next week. But it pulls apart fairly easy. I still have to seal around it but that will come after I solder the wires to the back side. The terminal is held on by a single #6 machine screw run from the other side through the center. It holds very well. Shiny black charge well provided by Rocket Junkies.

Viper 20.jpg

Nose cone bay for the Eggfinder. Riding on 24mm composites, sims are putting this thing over 2000 feet. A white rocket in a blue sky...I better track it.
There are many ways to put a bay in the nose cone. A fellow rocketeer was asking advice on how to do it without threaded rod and this was my suggestion to him. I built it this way so he wouldn't think I was full of fluff.
Just a simple centering ring epoxied above the shoulder. Kevlar looped through and brought together with heat shrink. Epoxy got on my kevlar so one tail was much longer than the other, but I put a loop in the smaller end and will hook the parachute there. The other end is about 18" and will attach to the main harness. To the (camera) left is the sled that will hold the Eggfinder. Yeah it looks rough but it cost me a bout a buck in material, so it'll work.

Viper 22 a.jpg

And the lower/outer ring. Sanded one side flat so the kevlar could come through and leave me room for a lid to seal the bay. I epoxied three #6 weld nuts on the other side and then grinded them to fit. That leave me options for sleds and lids and what not. A 38mm tube holds everything together and gives the Eggfinder a home. US Composites Fastek holds it together and seals the bay.

Viper 22.jpg

Here are two options for my tracking sled. The wood one I built just for this rocket. I'll test fit it and see how it goes. The green one was designed to go in the nose of my Cowabunga (Wastelander) and holds a RRC2+ and LiPo in a battery box. I can modify it to accommodate the Eggfinder if I must. The battery box is a bit tight (forgot to put in my tolerances). So I may redesign it just to be doing it. It does fit in a 38mm motor tube.

Viper 23.jpg

Now I have to mash out what I will do with rail guides. Probably well nuts, spacers and a plain jane ole buttons. Looking like that is the easiest and most reliable though I have never tried well nuts. Anyone got two #6 well nuts they would like to donate so I can try them out without buying a pack and paying 6 bucks shipping? Anyone? :smile:
 
I had two full weeks off from work. Hoped I would get to work on this and a long list of chores around the house. Nope. Was sick, then the weather wouldn't cooperate, then the holidays, more sick, more weather, more holidays...it kept repeating, then a sick truck. Still not back to 100% (me or the truck) and the weather is surely not acting right. Got down into the low teens early this week. And that played all kinds of heck on my old truck. But back to the Viper

I did get my sled wired up however. Put some pieces of small body tube to act as conduit to help manage the wires. May pull the bulkheads and the RRC3 then paint and polish the board, but I got more stuff to do before I waste time doing that again.

Viper 24.jpg

viper 25.jpg

The good idea fairie come by and dropped an idea on me. I can put the panel on and fill in around it with spot putty. Then pull the panel and have a nice smooth hole right. Wrong. The stuff chipped and cracked off the body tube opening and stained the white panel. Now I will be painting the panel anyway, or I may just print/cut a piece of vinyl to cover it.

What's left:
EggFinder in nose cone. That will probably wait. Trying to save weight a bit to fly on smaller motors.
Main harness. Likely go with kevlar up here as well. Will save a little space and weight. I think I have some 1/2" polypro flat strap I may use.
Paint and Polish. Probably going with wood filler or just primer to fill the spirals then gloss rattle can. I already have red, yellow, white and black, so I should be good there. Doubt I will polish it up all shiny. Especially since I plan to launch it next month.
Rail buttons.
Sampling ports.
Switch access hole.
Rivet payload section.
Order decal from LOC.
Motor selection: Got a thread going in the Restricted section. Thinking about turning some 24/40 reloads into single use. It'll get me closer to what I want/need in the boost department while saving money and shaving weight on the business end of the rocket. I can boost on D15 blue thunders, and stage to Estes D12s or D9 whites and stay under 1000 feet. Should be a nice low shakedown flight. Will have to order the motors first and go from there.
 
I had two full weeks off from work. Hoped I would get to work on this and a long list of chores around the house. Nope. Was sick, then the weather wouldn't cooperate, then the holidays, more sick, more weather, more holidays...it kept repeating, then a sick truck. Still not back to 100% (me or the truck) and the weather is surely not acting right. Got down into the low teens early this week. And that played all kinds of heck on my old truck. But back to the Viper

I did get my sled wired up however. Put some pieces of small body tube to act as conduit to help manage the wires. May pull the bulkheads and the RRC3 then paint and polish the board, but I got more stuff to do before I waste time doing that again.

View attachment 335692

View attachment 335691

The good idea fairie come by and dropped an idea on me. I can put the panel on and fill in around it with spot putty. Then pull the panel and have a nice smooth hole right. Wrong. The stuff chipped and cracked off the body tube opening and stained the white panel. Now I will be painting the panel anyway, or I may just print/cut a piece of vinyl to cover it.

What's left:
EggFinder in nose cone. That will probably wait. Trying to save weight a bit to fly on smaller motors.
Main harness. Likely go with kevlar up here as well. Will save a little space and weight. I think I have some 1/2" polypro flat strap I may use.
Paint and Polish. Probably going with wood filler or just primer to fill the spirals then gloss rattle can. I already have red, yellow, white and black, so I should be good there. Doubt I will polish it up all shiny. Especially since I plan to launch it next month.
Rail buttons.
Sampling ports.
Switch access hole.
Rivet payload section.
Order decal from LOC.
Motor selection: Got a thread going in the Restricted section. Thinking about turning some 24/40 reloads into single use. It'll get me closer to what I want/need in the boost department while saving money and shaving weight on the business end of the rocket. I can boost on D15 blue thunders, and stage to Estes D12s or D9 whites and stay under 1000 feet. Should be a nice low shakedown flight. Will have to order the motors first and go from there.

Looking nice! I like the conduits.

Could you use D21s in adapters for the first "round"? That would keep it low and avoid using whites.
 
Yes I could, I'll have to check out the thrust profile and run sims etc but those should have sufficient max thrust to do the job. Will have to acquire adapters but no worries there.
I had thought about adapting down at one time, don't know why I dropped that idea. Pending sims, that is likely what I'll do. Thanks for bringing it up.
I used aluminum tubes for conduit in the past but it was on my first sled and turned out to not work very well. These are gonna work great. Easy wire management without zip ties.
 
OpenRocket is saying the D21s will have plenty of punch to get me off the pad at over 50 ft/s. Staging to D12s will hit about 1000 ft. That's just about what I am looking for.

That is with an estimated weight. I may be able to get most of the pieces weighed tomorrow to have better numbers on the finished weight. If I have to I can go ahead and step up the boosters to the E30s or E28s and air-start C11s. That sims to ~1500.
 
Got my "as of now" weight today. I was WAY off on my estimates. Right now she weighs 33 ounces. Which changes my motor options.

Adapting down to the D21 is out. It leaves the rail at about 41 ft/s, which I'm good with, and cruises to about 200 feet. LOL. Would be cute flight for my yard.

My best bet is going to be turning the 24/40 loads into single use motors. Even with buying extra nozzles and all the pieces, I'll come in cheaper. Especially in the long run. I may can turn the RMS nozzles on my lathe and will surely try one or two. And I am sure not in the market for buying 3 more sets of 24/40 hardware. One sure, but not three. If I go with commercial single use, this thing will cost as much to fly as my Tyrannosaur.

So it looks like I am going to boost on E28Ts and air-start some D9Ws. That is going to get me going at 55 ft/s to an altitude of 1122. If I miss the altitude, I will still be safe to +/- 200 feet.

Plan to set the RRC3 auxiliary port as follows:
Event -> Timer -> Loop Comparator -> One Shot

The RRC3s "Launch" event is when the rocket reaches a set altitude, if I understand it.
So my plan is to set the arming altitude to 100 ft with a timer of 0.2s then a loop comparator of 150 ft. I may can eliminate the timer, but I want the practice.

Sims are showing it 4 Cal overstable, that will likely change when all is said and done. And showing it weather cocking pretty bad so I want the air-starts lit before the boosters burn out. I'll save the long coast for when I take it higher. In my experience though, weather cocking hasn't been much of an issue, even with overstable birds.
 
Small update. No pictures. Just a black motor and a scruffy looking rocket in 3 colors of primer.

I've been sidetracked with working on various projects including telemetry, parts for my 5" project and a few other odd ball things. But finally got going again.

The weather finally straightened up and synced with my schedule so I could get this thing primed and wet sanded. Now she is gassing out and waiting for paint. I am not going to worry about filling all the spirals and imperfections, then polishing it up. It is a test bed for clusters and air-starts after all and has an decreased likelihood of survival. :D

I finally got all my motor pieces in and assembled me one of the E28Ts. That resulted in my first ever motor CATO. I had it nozzle up and the igniter didn't pop out. As soon as it got pressure, it split the case and blew the nozzle off. Round 2 was today with one of the D9Ws. I mounted it nozzle down and it worked just fine. After the first igniter failed. Stupid thing, so annoying. On the ground is bad enough, but I will be relying on two to light at the same time about 300 foot up. It was a bit louder than anticipated (which is just fine with me) and my neighbor knew I was up to something and came over to investigate. LOL. He knows I am in to guns, and rockets, and other things that smoke, pop, bang, etc. I showed him the spent motor and described a little about what I had going on and his response "Well I am about to have a lot of free time on my hands. I retired in November you know."

The near-wife and my daughter were behind the barrier and it shocked them both with the roar. I was pretty darn excited when it fired. Being a White, it sputtered for a bit before it came up to pressure and I was disappointed at first...thinking "Aww Man." Then it pressured up and roared. WOOHOO. VICTORY!!

Guess I need to get me a decal ordered. More updates soon I hope.
 
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Decals on the way from Stickershock via LOC Precision. Thanks for the support guys.
Maiden flight was supposed to be Saturday but with the hiccup in the decal department and my second guessing my air starts I have been thinking about postponing the flight. But the decision was taken from me by the weather. Our launch has been postponed til March. And it's doubtful I will make that one. But we'll see. May be late April or early May before I get to fly again.

I don't like flying an unfinished rocket. The flight and recovery of a rocket, to me, is the final stage - it is finished at that point. I have yet to go back and finish an unfinished rocket once it has been flown, but I have only flown one unfinished anyway. And now that the launch has been postponed, it's gonna be tough to resist at least a wet sanding and polishing before applying the decals.

Mr Rocket Junky printed me up some rail button standoffs to bring the rail buttons out enough to clear the forward sections of the rocket. Best of both worlds: conformal but uses standard rail buttons so no binding on the rail.

Viper 26.jpg

The weather has held off long enough today for me to get the MMTs painted red. Masking will come off tomorrow and I will see if I want to wet sand and polish. I'm thinking no. LOL

Also did a ground test using a charge from one of the motors. BP weighed in at 1/2 gram. Great separation and the plug pulled right out with no issues.

Keep forgetting:
Switch access hole
Rivet holes
Static ports
Pressure ports - well I did one to pass my wire through for the ground test, don't know why I didn't do the one in the payload as well while I had everything out
Seal the stupid DC plug.

Thanks for looking folks.
 
Got the masks pulled; doesn't look too bad. I looks good enough and will look great at "pad distance". The close up shots reveal a few imperfections but I'm not gonna sweat em. I don't want to sand and polish in the valleys between the MMT. I did a shoddy job filling some holes and left some divots behind. So no sense in polishing the thing up only to have riddled with divots. I didn't even bother trying to smooth the printed standoffs. On a positive note though, the printed access panel turned out really smooth.

viper 27.jpg Viper 28.jpg Viper 29.jpg

I'm thinking I need more color to break up that large expanse of white, but the decals will handle up on that. A black nose cone maybe. Red nose cone would probably work better with the decals.

Decided to wait on the decals before I got to drilling all my holes. That way I won't cover my holes with decals...again.

Anybody ever saw a 24mm 1G home made single use motor? At 24/40 D9W sans the hardware.

Viper 30.jpg

How is that for cute? Yeah there will (probably) be comments about the epoxy on the nozzle or some other such stuff, but this one has been test fired, successfully. The other four are much cleaner than this one. With slices of body tube acting as thrust rings.

More updates soon, I hope.
 
Finally an update:
I still haven't flown this thing. I got my hands on some low current starters from a fellow flier at our last launch, but they wouldn't fit through the nozzles of the D9s. They would (probably) work if installed them prior to assembly. I still haven't tried two on a single 9 volt though.

But I think my problem is solved. I got a 450mAh, 3 cell, 25C (50C) burst LiPo from Amazon; along with a MOSFET trigger board rated at 400 watts, it can handle up to 30 amps. I hooked everything up to the AUX channel on my RRC3 and used it's software mDACs to fire the AUX circuit. It lit two starters (in parallel) immediately. A big sigh of relief. Tested with Christmas lights afterwards to make sure nothing burned out, all's good. The RRC3 will handle dual deployment and air starts.

So now I had to modify my lower bay. I cut out the board containing the terminal block and clamp and made me a battery box for the new LiPo. The MOSFET board will be mounted to the lid of the battery box. The battery weighs 1.68 oz and the box, battery, board assembly weighs 2.6 oz. I meant to shave some weight before gluing the box in but didn't. I knew there was a reason I hadn't glued it in but couldn't thing of it. A little extra weight down there lowered the stability a bit (a good thing), I am still around 4 CAL, and the rail clearance is still 51 ft/s. Sims to a 938 feet. I think I am good to go. FINALLY!

Next scheduled launch is next month. Maybe it will fly then.

Just realized I never posted pics of the final product. I'll get some soon.
 
Mikey that is really cool. Good luck with all the mods and electronic air starts. My son built one and it was awesome. Until the day we tried to fly it with only two motors due to smaller field. We plugged the unused motor mount tubes so we didn't lose pressure for ejection. One of the D12's failed to come up to pressure at the same time as the other, make it stall on the rod for a second. It left slower than normal and flew horizontal shortly after clearing the rod. The impact with the ground was at full power.

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Ugh. That isn't good at all. Thanks for the well wishes.
I am going with blues to get it off the pad, they seem to pressure up fairly quickly. But D12s usually do as well. Sure hope both of mine light at the same time. And then again for the airstarts.
 
Just don’t go with white lightning like I did that day. Lol
:)
Yeah,,erhm,, my airstarts are white lightning.:oops:
I intend to light them before the blues burn out so hopefully the blues will keep it mostly vertical if one of the whites takes longer to pressurize. The key here is to make sure the starters don't pop out when they light, like they always do when I light a green.

And now I seem to have misplaced my chute, spare cover and screws to hold the cover on. I didn't much care for the LOC chute to begin with but now i need to buy a replacement...gonna wait and buy it the day before I find my other one LOL
 
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