Night Launch Odd Roc Build Thread

[dixontj93060]

Well I have been attending Midwest Power since MWP3. If you have attended this launch before you know that one of the highlights is the night launch which is held on Saturday night which is usually on or around Halloween night. As such, you have some strange things flying overhead: Jack-O-Lantern's, Witches Brooms, Flying Saucers, etc. I have had, let's see, three previous rockets that were modified with appendages to fly at night just to participate, but no rocket dedicated for night flight specifically for this event so I figure it's about time...

I thought of purchasing some of the superb night flight rockets that are available now (e.g., Leading Edge Alien (http://www.cdimodelrocketry.com/proddetail.php?prod=LE51ALIEN)), but then I wanted it to be a bit more distinct. So off to eBay to find components and finally I found the "perfect" body. But to add some suspense, I'm not going to reveal what it is exactly. As this build thread progresses I'm sure you will see more of the actual rocket, but to make it a little more interesting, the first one to guess what it is will get a small prize.

To start, here is the Rocksim file (name changed to "protect the innocent"):

[SMR]

the first one to guess what it is will get a small prize.

Casper the Friendly Ghost?

or, an alien?

[dixontj93060]

Casper the Friendly Ghost?

Good guess, but no.

[SMR]

How many guesses can I have?

although, technically, I am already ...


the first one to guess what it is

unless you meant "the first one to correctly guess what it us"

:wink:

also, it might be an alien.

[dixontj93060]

No limit on guesses.


How many guesses can I have?

although, technically, I am already ...



:wink:

[dlb]

MWP will have DRA-GLO from Wildman this year from what I hear.

[dixontj93060]

Yes, another excellent night flight rocket!


MWP will have DRA-GLO from Wildman this year from what I hear.

[Scotty Dog]

I cannt open the file,so I have no idea the size.However Ill guess "The Jolly Green Giant"? Or The Green Hornet?

[dixontj93060]

I cannt open the file,so I have no idea the size.However Ill guess "The Jolly Green Giant"? Or The Green Hornet?

No, but green is headed the right direction.

[redsox15]

green goblin?

[dixontj93060]

green goblin?

Again, good guess, but sorry no.

(Actually didn't expect to get so many guesses until I started posting some build pics--but hey, kinda like Family Feud and the fast buzzer advantage).

[dixontj93060]

Ebay buy numbers 2, 3 and 4... First, super bright LEDs--4 arrays of 9 each for the aft section and 4 arrays of 3 each for the fore section. Second, good, strong 3 cell Lipo's to power the LEDs and blinker controls (probably overkill, but wanted a bit of forward weight anyway). And third, a Lipo regulation/control circuit as a safety precaution to shut down at a low-voltage limit. You can see a video of the LED's working in this past post (http://www.rocketryforum.com/showpost.php?p=179160&postcount=1) (BTW, the theme item mentioned in the linked post is still around, but it didn't provide the size/distinction that I wanted in this project, thus the recent eBay purchase referenced in post #1 of this thread).

[Scotty Dog]

Green With Envy or this.........

[dixontj93060]

Green With Envy or this.........

Oh, Kermit would be a good one! But no.

[dlb]

Green Lantern

[dixontj93060]

So just a bit of philosophy on this rocket build. My approach will be to build a rocket in three pieces, the booster or aft end and the payload/chute bay in the fore end and finally a cap, on the chute bay which is the nosecone in the Rocksim file. The idea is that the above components could be a stand alone rocket and flown separately. What makes it "odd" is simply the plastic skin. The plan is to have this skin completely separable from the rocket proper and will be assembled by sliding the components in place and using appropriately sized and placed screws and T-nuts to hold the assembly together. Although there will be some support from the skin, I don't want to rely on it for any structural support.

To that end, I started cutting and fiberglassing the central rocket components. A picture of the progress is below (Kinda messy as I had to do it fast between conference calls). I will need a 2.6" tube of ~25" in length and a 4" tube of approximately 13" in length. The problem is, as I've stated before, I'm not a craftsman and don't draw the build components to the nth dimensional detail. Couple this with the complex curves of the skin, and I feel it is best to rely on some "fit and adjust" methods during the build. Thus the tubes you see in the attachment are oversized in length and will be cut as I find out exactly how the fore and aft sections will mate together.

Some that pay attention to detail may see the coupler piece laying on the floor. This is the shoulder for the nosecone cap. It is also being glassed but the laminate is inside the tube. Some that really pay attention to detail may see a "step" at the end of the 2.6" tube. Yes it is really there. The 2.6" tube is actually a coupler tube and I added a section of 2.6" airframe in the area where the fins will attach as I want to get double wall strength in this area where I will have TTW mount as the span of the fins is fairly large compared to the 2.6" tube diameter. Finally, those with even more attention to detail may see black lettering on the 4" airframe section which identify these tubes as leftovers from this flock (http://www.rocketryforum.com/showpost.php?p=208096&postcount=1).

[dixontj93060]

The reason the rocket has to be built in three pieces is that the "skin" has a skinny neck approximately one third of the way down from the fore end. So I will assemble the booster and fin assembly and then insert that piece from the aft end. There is already an ~4" access hole in the bottom of the skin (see attached). This will be used to insert the main tube and fin slots will be cut to slide the whole assembly in. The larger chute bay will be inserted from the fore end where an 8" hole will be cut in the top of the skin (again this piece will be bolted on a bulkhead on the top of a 4" coupler and will act as the nosecone). The holes on the bottom and top are oversized as the electronics will be mounted in slots on the side of the appropriate tubes, 36 LEDs in the lower 2/3rds and 9 LEDs in the top section. There is a convenient plastic cap on the back of the skin where, as a yard ornament, this "creature" was lit up with an incandescent bulb (pic attached). I thought about mounting the batteries and switches here, but opted not to as I need to move weight forward in this design.

[dixontj93060]

Green Lantern

Again a good one. I like the Green Lantern. But no.

Hint: It isn't an actual character by name. In other words, it's not really a "who", like the Jolly Green Giant or Casper the Ghost, it is more like a "what."

[UPscaler]

A missile off the Joker's helicopter?

The green goblin's missile?

Green goblin's grenade?


Frankenstein's Monster?



Braden

[dixontj93060]

A missile off the Joker's helicopter?

The green goblin's missile?

Green goblin's grenade?


Frankenstein's Monster?



Braden

Braden,

Sorry. Although he could be considered a menace like the Green Goblin, no, no, no and no to your guesses.

-Tim

BTW, second layer of FG applied.

[Scotty Dog]

gangrene

[SMR]

gangrene

Really? Okay. "Puss"

(that would have been my follow-on in the Word Association thread.) :D

followed shortly by... "Hey, you guys are going too far"

followed immediately by... "Ogre"

or, an alien?


http://asubi.mn/images/asu/1009240057.jpg

[dixontj93060]

Really? Okay. "Puss"

(that would have been my follow-on in the Word Association thread.) :D

followed shortly by... "Hey, you guys are going too far"

followed immediately by... "Ogre"

http://asubi.mn/images/asu/1009240057.jpg

Sather,

Shrek is a good guess (not even commenting on gangrene). And although this thing is non-human like Shrek, your guess is incorrect.

-Tim

[SMR]

Oscar the Grouch? Tinkerbell? Robin Hood?

http://www.watchmyfoodgrow.com/wp-content/uploads/2009/02/oscar_the_grouch_from_sesame_street.png http://www.morecoloringpages.com/coloring_pages/sm_color/tinkerbell1.gif http://static2.stuff.co.nz/1233108507/136/532136.jpg

Or, an alien?

[dlb]

Hulk

[SMR]

Hmmmm, let's see. You're from Indianna, right. So it must be...

Green Bay Packers

http://www.betsbg.com/sites/all/themes/zeropoint/images/articles/colts_0.jpg

or, an alien?

[dixontj93060]

OK guys, now you are getting cold. Like I said, not a proper name or individual like Tinkerbell; not human like the Green Bay Packers. Of course the Hulk is part-human and the right color, but no.

BTW, some rough cut centering rings and bulkheads done over lunch.

[daveyfire]

An alien?

(on the brain probably because I watched "Paul" a few weeks ago while we were finishing up our motor for LDRS. Which reminds me I also need to get up a better description of that motor in the research area. Back on the to-do list!)

[gdiscenza]

I'm thinking it's a troll.

G.D.

[jeffgeraci]

If it winds up being a frog, it's lame. If it's a turtle, it's beyond lame. If it's an alligator, it's super super lame. So my guess is:

[dixontj93060]

If it winds up being a frog, it's lame. If it's a turtle, it's beyond lame. If it's an alligator, it's super super lame. So my guess is:

You are very close (I think). What is this?

[jeffgeraci]

You don't know Mike Wazowski??????????:y: time to google!

[jeffgeraci]

My final guesses, in order of "hunch" level (you said no limit):

1. Green gnome
2. Martian
3. Golem from LOTR
4. Crocodile
5. Wizard
6. Dragon
7. "Slimer" from ghostbusters
8. A CHERNOBYL survivor (distasteful humor, sorry)

[dixontj93060]

My final guesses, in order of "hunch" level (you said no limit):

1. Green gnome
2. Martian...

We have a winner!

Shows persistence and a bit of brainstorming pays off.

Other accepted answers would have been "Alien" or "Little Green Man"

[gdiscenza]

An alien?


We have a winner!

Shows persistence and a bit of brainstorming pays off.

Other accepted answers would have been "Alien" or "Little Green Man"

Ummm...if Alien was an accepted answer, then Daveyfire got it first....

Just sayin....

G.D.

[dixontj93060]

Ummm...if Alien was an accepted answer, then Daveyfire got it first....

Just sayin....

G.D.

Wow! You are right! I didn't see David's post (was packing up to leave the office I think).

OK, I'll give out two prizes. David and Jeff PM me with your mailing addresses.

[Scotty Dog]

6DnD9RBdkfE&feature=related

[eggplant]

What is the prize?

[dixontj93060]

What is the prize?

Well, the initial prize was a new parachute from my stash. I'll have to come up with another appropriate one for David.

[daveyfire]

Well, the initial prize was a new parachute from my stash. I'll have to come up with another appropriate one for David.

Nah, don't worry about it... I kind of cheated, I have seen a rocket based on a similar alien figure before (at the January 2002 ROC launch, see attached), and when I saw the contours of the injection molded thingamabob, I knew it had to be one. IIRC this flight didn't go exactly as planned, so I'm looking forward to seeing you pull it off successfully!

[dixontj93060]

Nah, don't worry about it... I kind of cheated, I have seen a rocket based on a similar alien figure before (at the January 2002 ROC launch, see attached), and when I saw the contours of the injection molded thingamabob, I knew it had to be one. IIRC this flight didn't go exactly as planned, so I'm looking forward to seeing you pull it off successfully!

I expected someone had tried it before. It's just too tempting. But he kinda cheated... adding a whole nosecone on top? Although his rendition looks very nice.

Successful. I am planning on it. As Pat G. said more than once on the LCO stand at LDRS30, "put a big enough motor in it and anything will fly straight." ;) Planned motor: J340M (metalstorm) which should be especially nice at night.

[jeffgeraci]

Does anyone know of anyone who has launched a mannequin??? I was considering modifying a mannequin to look like iron man, and mount the motors in the hands.

[SMR]

As Pat G. said more than once on the LCO stand at LDRS30, "put a big nose weight enough motor in nose weight it and anything will nose weight fly straight."

Yup. That was truly subliminal...

:wink:

[dixontj93060]

Does anyone know of anyone who has launched a mannequin??? I was considering modifying a mannequin to look like iron man, and mount the motors in the hands.

The person set up across the fire lane from me at LDRS30 had a mannequin rocket in a bridal dress he called "Shotgun Wedding." Sorry, I don't know the name of the flyer, but I believe he flew it on Saturday.

[daveyfire]

But he kinda cheated... adding a whole nosecone on top?
I know, right? I hope yours has a creative deployment mechanism that keeps the exterior lines clean!

Planned motor: J340M (metalstorm) which should be especially nice at night.
Far cooler than the J180T that he chose. This should be awesome. Looking forward to the rest of the build!

[dlb]

We have a winner!

Shows persistence and a bit of brainstorming pays off.

Other accepted answers would have been "Alien" or "Little Green Man"

Dam, I see these every once in a while, and old Halloween Alien, purrrfik for convertions.
Very Cool!

[jeffgeraci]

What is wrong with us? Seriously, what is wrong?:confused2:

[dixontj93060]

Finished the centering rings and bulkheads last night and in doing some of the trial fitting and, considering I want this thing around for a few years, I am gravitating toward using well nuts and bracket/grommet combinations to assemble all the plastic skin and lexan fins around the rocket proper. I want to provide some "give" at the connection points to relieve stress at landing and the durability of the epoxy-to-plastic connection is questionable anyway.

In addition I took a look at my Lexan stock and found it was at ZERO :y: (I thought I had a piece stashed away large enough to do the three fins). Since I had to pick up some Lexan I decided to up my chances for a successful flight by migrating to four fins.

Finally, looking at the head shape, I actually have more room than I thought in the nosecone "bowl" and thus have adequate space to attach "muffin pan" lead weights as needed (shown in use in this build (http://www.rocketryforum.com/showpost.php?p=109925&postcount=1)).

Attached is the adjusted Rocksim file and a picture of the Lexan standing beside some carbon honeycomb I got in recently for a future high performance 98mm design.

[SMR]

This is going to be awesome, Tim. Looking forward to seeing her fly at MWP. The night launch alone is enough reason to make the drive.

:wave:

[dixontj93060]

Looking forward to seeing her fly at MWP.

Here's another guy that is looking forward to seeing her (him?, it?) fly (my grandson :D)...

[jeffgeraci]

Here's another guy that is looking forward to seeing her (him?, it?) fly (my grandson :D)...

With halloween coming, you should body-paint your grandson green and have him pose next to the rocket! What a great picture that would be.

[dixontj93060]

A small red flag raised on this build when I found out from my father-in-law that he has his band saw torn down. The band saw is what I have used in the past to cut Lexan fins. I tried doing this with a jigsaw with no avail as I got ragged edges (maybe there are other options?). So for now I am waiting for him to get it back together. Not panicking yet, as he's pretty good about getting things done when he knows there is a need.

In the meantime a few boring steps... 1) top two centering rings attached to motor mount, 2) motor mount attached to booster body, 3) inside fore end pic of motor mount, 4) "interface" CR attached to aft end of chute compartment, 5) inside pic of chute tube.

[dixontj93060]

Tons of company over the weekend so slow progress. Surgery conducted on the alien (top of head cut off) and a bunch of fitting and sanding. To fashion nosecone a coupler tube section was cut with bulkhead attached shown on the left below. The base was epoxied on the end of the booster tube shown on right below.

[dixontj93060]

My father-in-law got his band saw back together so the "log jam" was cleared. I cut fins last night. This morning cut slots and am now tacking them in place before applying the internal fillets. Pretty healthy span on the fins, but of course much of the surface will be "buried" inside the body.

[dixontj93060]

On to internal fillets. And to just be sure I'm J-capable, I am adding a quick/dirty layer of FG across the fin/body tube fillet area up to about 1.5" from the root. Nice thing about this build, all the laminating and epoxy joints are hidden so they don't have to look good, just be functional.

As I'm contemplating final assembly, I am getting fairly paranoid when it comes to the disparity of materials. Polystyrene, Lexan, phenolic, wood, metal brackets, etc. At first I had planned to make as many connection points as possible. For instance a big heavy fillet where the wood base CR attaches to the Lexan fins, and then put L-brackets along the body and attach the fin exit area with screws and grommets. But then considering the variation in landing angles I began to worry with a wood base hitting and then the plastic body and then experiencing a torquing of the Lexan fins... So now I'm leaning completely the other way, i.e., minimizing the attachment points between disparate materials. So I'm down to 4 well nuts attaching the base plate to the body feet area and then another 4 well nuts attaching brackets to the interface CR in the neck/shoulder area. Of course the body would also be held laterally by the four fins through slots in the body, but there wouldn't be any specific attachment at the fin/body joints. I'm less worried about the top of the head/nosecone as it has more than enough attachment points and structure to hold the nose weight in place.

Any thoughts anyone has on the above would be appreciated.

[dixontj93060]

Well, finally finishing the fin can. Aft end shown with CR now being inserted and then left to dry. The fin can looks pretty rough... not only due to the fiberglass layers showing through the clear Lexan through the fillet area, but also because I still have the plastic film on the fins. I'll keep it there until I get the final fit in the body to alleviate any errant scratching.

[SMR]

Coming along nicely. I was going to comment that you build fast, Tim, but I realize you just use your time very efficiently. I'd still be building the motor mount. (Cause I spend a lot of time day-dreaming about what it will look like finished.)

P.S. Is your grandson coming to the launch? It looks like he might already be emotionally attached to the little green man. You absolutely cannot crash it.

[dixontj93060]

Coming along nicely. I was going to comment that you build fast, Tim, but I realize you just use your time very efficiently. I'd still be building the motor mount. (Cause I spend a lot of time day-dreaming about what it will look like finished.)

Yep, no reason watching paint, er, epoxy dry... Take a 10 minute break from work mix/apply/clamp and then back to work for two hours--then repeat.

[dixontj93060]

P.S. Is your grandson coming to the launch? It looks like he might already be emotionally attached to the little green man. You absolutely cannot crash it.

Uh, oh... PRESSURE :eek:

[dixontj93060]

Big learning experience cutting the fin slots in the body today. #1 it is nearly impossible to map out straight fins on complex curves of a body like this--not just an arc, you are dealing with undulations. #2 cutting four 9" slots in the bottom of the plastic body removes a lot of the rigidity of the structure. So combining the above, I do have the fin can inserted in the slots, albeit in slots that are not too smooth and wider in most places than they need to be, and I am now worried about the overall structure of the body under thrust. Thus I am going to flop back and move in the direction of tying everything together to get a more rigid structure around the MMT. This will unfortunately involve foaming around the feet area of the body and blocking some of the light that will be shining from the LED's, but, all-in-all, I believe the stability and safety of the craft is more important than the light effects. Since I will be filling some gaps around the fin exit area, Rustoleum 2X Key Lime Green will be my new friend.

[dixontj93060]

Actually got quite a bit done today. Most of the sub-assemblies were fit together. Just a few snapshots... First the main booster connected to the body from the bottom with eight well nuts; second the interface centering ring placed and installed--this is critical to get right as you need to secure the chute bay which is done with the four #8 studs and then cross-brackets at 45 and 225 degrees hold the CR in place with a 1/4-20 bolt which will double as the main body connection for the shock cord. The last two pictures are the LED sub-assemblies. Given that I'm foaming the fin can into the main body it will be nearly impossible to maintain any electronics on the booster. One of my priorities in any build is to be able to repair if any mishaps occur so I decided to build two "sleeves" that hold the 36 main body LED's. These sleeves slip down over the booster tube from the fore end making everything accessible from the nosecone area. Finally the mounting for the 9 LED's on the outside of the head/chute section (no changes here--one more triple LED array not shown but is on the back of the 4" tube).

[Micromeister]

Wow!
He's a LOT bigger then I thought!

[dixontj93060]

No posts for a few days... Besides completing a few work deadlines, I have been wrestling with the toughest issue in this build... I am fine with everything from the eyelids down (if aliens have eyelids), but have real issues with anything above that, i.e., the nosecone and fitting 2lbs of weight up there. I could have posted some intermediate pictures, but it just would have been confusing and a waste of your/my time. Suffice it to say, there is far less room in the upper cranium area than I expected, and extending an attachment down into the chute tube is out of the question--I'll be doing all I can to get the Nomex protector and an 68" chute into that area. In any case, after trying four options, I believe I have found a method to get my 2lbs of weight into what is 3 vertical inches (like Red Bull says, think "wings"). More later...

[dixontj93060]

Had a bit of a "blow out" when foaming. Not to be unexpected although that Frog tape seemed very secure. Oh well, I'll just have to be careful carving so as to not scratch the Lexan fins.

[Grimracer]

well of course.. aliens ooze off white...!

Looking good Tim.. Hope to make it to mwp to see it in action.

Grim

[dixontj93060]

well of course.. aliens ooze off white...!

Looking good Tim.. Hope to make it to mwp to see it in action.

Grim

Mike,

Actually got it all trimmed up and shot the foam with a coat of Key Lime green which is a fairly good match--more pics soon.

-Tim

[dixontj93060]

Well I haven't had much time to work on any rockets, let alone this one. Cut up an oak tree and split it today and installed half a floor in one of my rental houses, but just to bring this thread up to date...

We now have "alien green" foam. If you look close it is a bit rough, but from 10 feet, it blends right in. Second the inside of the nosecone (inside top of head) is ready to install the lead "muffin pan" weights--2 lbs will be sitting on the opposing brackets in the second picture. Next wiring assemblies are installed internal to the main body area and Velcro cross straps are located in the "cheek area" to hold the battery packs. Finally putting on "war paint"-like alien green reflectors for visibility during recovery just in case the lights are lost for some reason.

[Grimracer]

anymore progress you can share Tim?

So far so good!

Grimracer

[dixontj93060]

anymore progress you can share Tim?

So far so good!

Grimracer

Well, two steps forward, one back... I snapped the interface CR when I was tightening it down so I had to cut a new one. Given it's position/importance I bumped to up to a higher quality, thicker (1/2") plywood. Now I have to get longer studs. Still planning to fly it at MWP though so more pics will be forthcoming.

[dixontj93060]

I did make one change to the design regarding the nose weight. As was pointed out so subtly earlier in the thread, nose weight is fairly important in this design. I made provisions to put 2 lbs. in the nosecone (top of cranium) but after putting it together I felt uncomfortable with that heavy of a nosecone and getting it ejected effectively. So instead I took half the weight and mounted it at the bottom of the parachute bay.

[dixontj93060]

OK, wiring is pretty much complete now. I do have on order a small 11.1V LiPo from Tower Hobbies to run 6 more LEDs in the nosecone area. I decided to add these as it looks funny with the very top of the head being dark compared to the body and rest of the head. I will mount the battery and LEDs when I get them and will wait on an "in the dark" picture until then. In the meantime as you can see the larger 11.1V battery is mounted inside on one "cheek" and the two LED controllers are on the other side. In the center is the loaded parachute compartment. Under the parachute are the two lead "muffin" weights I had to reposition from the nosecone and they are mounted against the bottom CR of the parachute compartment.

Although I am almost done, there are lingering "pains in the butt" that I am dealing with:


One of the 3-position LED arrays in the head went south on me. I popped it open and found the positive wire had broken. I resoldered it, but am still only getting 1 of the 3 LEDs to light. Unfortunately this LED array was pointing forward on the right cheek. I am going to cut the wires and remount the back LED array in its place to get the light balance I want.
Nosecone alignment. This is a real pain. After cutting the top of the head the molded plastic "relaxed" on both the nosecone bowl and the top of the head area so now I'm not getting perfect alignment all around the perimeter. I am testing a few of the automotive clips that are used to attach bumpers, fairings and such. Hopefully they will work, but I'm open to other ideas (gap is approaches a 1/4" in one spot).
I just don't have enough room in the parachute tube to get the shock cord, 68" parachute and a Nomex blanket in there. I am considering adding some type of baffle to the top of the main booster tube to protect from the ejection charge. Alternatively I just stuff the top of the main booster tube with dog barf, but it will be a pain to get in there because I have a 1/4-20 cross bolt as a mechanism to hold the interface CR in place and attach the shock cord. Needless to say, the jury is still out here on which direction I will go.

[dixontj93060]

OK, attacking each issue one at a time and getting final items completed...


The steel mesh makeshift baffle looks like it will work.
Used automotive body tabs to help align top-of-head nosecone. Not perfect and really not completely happy with it, but it is better than it was before. Since time is running out, I'm going to have to go with it.
Although held together with four bolts, I added epoxy reinforcement to the top of the nosecone assembly to remove any final wiggle.

Remaining items:


Rewire/swap the right side and rear LED array's in the head.
Ground test? Although this is motor deploy, with the weight of the nosecone assembly, I'm concerned. I will try to ground test a standard 38/720 case & ejection well. Hopefully I'll get this done Sunday night.

On the final point above, according to calculations 1g of BP will give me 15psi at the end of the booster tube and I believe a standard 38mm ejection well holds 1.5g which would be 25psi. All good; but then I have the step from 2.5" diameter to the 3.9" diameter of the parachute compartment--what happens then? I'm pushing on more area/a bigger piston so do I get a positive effect? Or, because the overall volume increases at the end of the chamber is the effect negative? Inquiring minds want to know.

[ECayemberg]

Tim, get back to painting!

Regarding ejection gas pressure. I don't know, the larger the diameter, the less psi required to move the surface, but then again the 4" tube provides more volume. I'd say wrap a couple wraps of 1"+ masking tape around the outside of the well (knurled part), add 3 grams BP total, tape it up, and it'll deploy!:kill: Blow it out or blow it up!

Now get back to painting!

-Eric-

[dixontj93060]

Now get back to painting!


Ya, well, kinda wish I could... Client dinner tonight and I'm in my 24 hour dry period. Next round of painting tomorrow morning at 7am.

[SMR]

On the final point above, according to calculations 1g of BP will give me 15psi at the end of the booster tube and I believe a standard 38mm ejection well holds 1.5g which would be 25psi. All good; but then I have the step from 2.5" diameter to the 3.9" diameter of the parachute compartment--what happens then? I'm pushing on more area/a bigger piston so do I get a positive effect? Or, because the overall volume increases at the end of the chamber is the effect negative? Inquiring minds want to know.

You're making great progress, Tim. Look forward to seeing her (him?) next week.

To speculate on your BP question... a little of both. Pushing on a bigger area with the SAME pressure does give more force. But you will loose a bit of pressure in the step to a bigger tube, since the expanding gas effectively diffuses a little in the larger volume. Might be pretty close to a wash, though. Stepping to a larger diameter tube is really not any different from just having a longer tube of the same diameter... just more volume for the gas to fill.

[dixontj93060]

Kinda what it it going to look like on the pad before the J340M ignites into a shower of sparks!!!

7KzWfyim_7k

[GDJ]

I love this! :D

[dixontj93060]

I love this! :D

Thanks.

No pics or video, but this afternoon's ground test went great. Nice ejection of nosecone and parachute. Steel mesh protected well. Standard 38mm motor charge worked just fine.

[SMR]

Kinda what it it going to look like on the pad before the J340M ignites into a shower of sparks!!!

7KzWfyim_7k

Wow, looking awesome. Weather forecast not bad, either. T minus 6 days.

(And you're right. Those clear fins really are tough to see at night! :smile:)

[Grimracer]

you are a sik man.,.. I LOVE IT..

Hope to see it fly and I have to tell you about the "UFO vewing" I had back in the early 80s.. (not kidding my wife can verify).. it was COOL!

Anyway.. Looking fantastic.. can not wait to see it fly!

Grimracer

[dixontj93060]

you are a sik man.,.. I LOVE IT..


Thanks Mike.

One last, but important thing... Rail buttons top and bottom. Top was put on with a well nut in the back of the head. Bottom was initially drilled into the base CR, but I didn't feel comfortable with the 1/4" thickness so I put a 1" L-bracket wrapped around the bottom CR and up the back (between the heels) with another well nut attachment.

[dixontj93060]

Flew last night at the MWP night launch. Delay was cored to six seconds but should've been even shorter. Got to about 800 to 900 feet. Late, but effective deployment. The Little Green Man was recovered fully intact with zero damage. Overall very pleased. (Videos were taken, but don't know if they will come out in the dark--I'll take a look when I get unpacked on Monday.)

[dixontj93060]

OK, super crappy video of the Little Green Man. But my friend couldn't really focus and/or see what was happening out on the range through the viewfinder in pitch black. You don't even really see the bright blinking green which I was happy with, but you do see the "comet trail."

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Goals for next year:

Get rid of iffy motor deploy and add an enclosed altimeter bay integrated with the back hatch.
Fly on an EX motor made for the Kosdon 38/1116 case (29+" long)

[dixontj93060]

Goals for next year:

Get rid of iffy motor deploy and add an enclosed altimeter bay integrated with the back hatch.
Fly on an EX motor made for the Kosdon 38/1116 case (29+" long)


OK, it is "next year" and coming up at the end of March is Thunderstruck '12 (http://www.indianarocketry.com/thunderstruck/) with it's inaugural night launch. And with that hoopla, I want to knock off #1 above. Motor deploy in the Little Green Man is tough as you are taking a J340M fourteen second delay and coring it down to four to six seconds--not recommended by Aerotech and, thus very iffy. So I wanted to add an altimeter to the design, but given the drag of it's dumpy body and it's typical flight profile with the J340M, it was questionable whether I would pull enough gees in a flight to only ~1000 feet to reliably trigger an alt. So searching for other alternatives I was glad to see this item (http://www.rocketryforum.com/showthread.php?t=31409), the µMAD, the go on sale. I received it yesterday and did a bit of "ground testing" today in the office. Nice little device from Wooshtronics (http://www.whooshtronics.com/products-t110/umad.aspx).

PWENZPjq3yY

[ECayemberg]

Tim,

I thought that the T-struck night launch is for FAA "Class 1" rockets...ie under 3.3 lbs and 125g of propellant?

I hope I'm wrong; I like the big stuff at night and look forward to another lil' green man flight!

-Eric-

[dixontj93060]

I thought that the T-struck night launch is for FAA "Class 1" rockets...ie under 3.3 lbs and 125g of propellant?

Oh, bummer... I didn't see that... Seems so un-Thunderstruck-like!

HMMM... I don't think I have a night launch rocket that will fly on less than an H-motor?!?

Oh, well, I guess I'm a leg up on MWP11.

[ECayemberg]

Oh, bummer... I didn't see that... Seems so un-Thunderstruck-like!

HMMM... I don't think I have a night launch rocket that will fly on less than an H-motor?!?

Oh, well, I guess I'm a leg up on MWP11.

Bummer; I was hoping I was wrong! Either way, the magnetic apogee sensor is interesting...will watch to see how it works out. I recall Transolve releasing a magnetic sensor for deployment years back...not sure if they still make it or if it caught on?

I don't really have any dedicated "class 1" night flyers either. Nothing wrong with getting ready for MWP10!

-Eric-

[dixontj93060]

Nothing wrong with getting ready for MWP10!


Yes, woops, MWP10.

[daveyfire]

Oh, bummer... I didn't see that... Seems so un-Thunderstruck-like!

Yep. We've twisted arms, cried, begged, groveled, and other such verbs to the FAA in Chicago, but they will not (and claim they have never) issued a launch waiver after dark. It's frustrating to show them the paperwork from other night launches -- especially ones in their own airspace -- and still have them claim they don't happen.

Yay bureaucracy! :bangpan:

[dixontj93060]

It's frustrating to show them the paperwork from other night launches -- especially ones in their own airspace -- and still have them claim they don't happen.

Night launch? NIGHT LAUNCH? Who said night launch?; just a bunch of us sitting around this field warming ourselves at the bonfire (started by, uhhh, ammonium perchlorate) :cool:

What happens at Thunderstruck, stays at Thunderstruck... http://www.animated-gifs.eu/leisure-games-dice/0031.gif

Who's the LCO for the night launch anyway?@?! :point:

[dixontj93060]

Well, finally got my apogee eject control integrated. Again, I am doing this because of the need to cut down the delay so far on big J/K motors. Taking 8+ seconds off a delay isn't recommended and just isn't very accurate. I will still use the motor eject as backup, but now will have as primary the signal from the Whooshtronics uMAD (http://www.whooshtronics.com/products-t110/umad.aspx). I mounted the control on the back plate. It was conveniently and originally there to mount the internal lamp for the Alien when used as a lawn ornament. I'm using reusable plastic rivets for easy access to switch the power on/off (especially important when working at night!).

90656

90657

90658

[cwbullet]

Well, finally got my apogee eject control integrated. Again, I am doing this because of the need to cut down the delay so far on big J/K motors. Taking 8+ seconds off a delay isn't recommended and just isn't very accurate. I will still use the motor eject as backup, but now will have as primary the signal from the Whooshtronics uMAD (http://www.whooshtronics.com/products-t110/umad.aspx). I mounted the control on the back plate. It was conveniently and originally there to mount the internal lamp for the Alien when used as a lawn ornament. I'm using reusable plastic rivets for easy access to switch the power on/off (especially important when working at night!).

90656

90657

90658

Thanks

[dixontj93060]

I was able to fly this again at the MWPX night launch. Got my timing screwed up so got there late and was almost the last flight. In any case, the Wooshtronics uMAD worked perfectly with separation right at apogee for a nice leisurely, slow recovery--much better than relying on motor deploy when you have to cut so much off the delay.