Excelsior! The 3/4 scale Nike Smoke[Success flew today!!!]

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If placed at the bottom, there's a potential for the flame front to blow some powder out noncombusted.

Stick the match on top, and all powder is trapped below so it has a better chance to burn.

For the folks that stay under 10k probably doesn't matter where one puts the match. I do agree with the statement above. I've blown 2 micro centrifuge canisters through and outside of cardboard rockets and no longer use unrestrained charges.
(Yeah, sometimes a Stupidhead has to learn the hard way!)

The high alt. folks have to be more persnickety and it appears that "gun barrel" like arrangements work best there. Kurt
 
How is the deployment charge affected by where the match is placed in the BP?

Why do you choose to put the match on top?

I have been working on some research on this. I agree the match should be on top of the powder.

Here is a test I did of an 8 gram charge with the match on the bottom:

[video=youtube;4UWoBhwvuWs]https://www.youtube.com/watch?v=4UWoBhwvuWs[/video]

In the slow motion you can see a large black column shoot out of the charge well, this is the the majority of the powder is being ejected and the flame chases the column of powder up. this is not going to produce the most efficient gas volume and a lot of the powder will go unburned.

By placing the match on top the flame front actually works its way down and compresses the power into the cup giving a better ignition.

The following test had the match on top and produced a noticeably more energetic charge. You could actually feel and hear the difference in the concussion of the charge.

[video=youtube;xW810k5AySQ]https://youtu.be/xW810k5AySQ[/video]

Mendal
Owner - Rocket Junkies
 
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Ok, The only problem here is the test didn't faithfully reproduce what is actually going on inside the rocket.
The diameter of the tube and how close the chute pack gets mashed down to the main charge has the effect to
contain the pressure. Apogee charges blowing down into the sustainer and main charges blowing up would be different. Again, with sport fliers staying under 10k, do a ground test and be happy with a charge that gently gets nearly to the full length of the harness. Tight chute packs will take more powder and more protection of the chute.

Using fixed charge cups? Fine, that's technically optimal but for my sport rockets, I'm not sweating the "blow-up"
charges (ie. ematch on the bottom) as I put a little more duct tape over the end contain the dog barf over the 4f charge and always works for me.

BTW, nice video. Kurt
 
I agree 100% that the video does not tell the whole story but it does give some insight to the events up until the tape gives out. In a contained tube even with the powder pushing out it is likely that there is enough containment that a majority of the powder will burn. In my mind the goal is to get as much powder to burn at the same time such that you get a uniform and predictable “push” from the charge.

And as stated nothing beats ground testing.

Also note that these are large powder loads, 8 grams is a lot of powder to ignite. The 16gram wells I made for Jim are actually 3 times the volume of the 8 gram wells. This is to try to keep as much of the powder together as long as possible.


Sent from my iPad using Rocketry Forum
 
I began using "gun barrel" type charge holders in 2010 when I designed the Space Cowboy 54mm for the fastest to 10,000ft. drag race at LDRS. The rocket would easily go over 20,000 ft.& did.
That's the altitude generally accepted where deployment can get wonky without proper containment.

These were the first iteration of the design. Rocket had a payload so there was room for 2 on each end of bay. Really not needed for main as it fires under 1000 ft.

attachment.jpg

Current day version with hex bottom removed, I still have them tapped for #6 all thread so I can just screw them on the tie rods and eliminate nut. Even on larger size BP's 3-4inch. I just use #6 size screw to hold on BP as tie rods are usually #10 or 1/4-20 size.

DSCN0276.jpg DSCN0469.jpg

No need for them on both sides as I mentioned, main deploys at low altitude & no room in NC when deploying with H.E.D. [out of cone]

dimensions are approx 1/2 in. diameter & 1.75 long.
I use 1 on 38 minimum with 2 matches in same holder for redundancy.

Here is an interesting test article/pdf done by Jim Jarvis.....[the other Jim] explain how all this works. Shows how when test 1 gram charges at equivalent altitudes pressures with his chamber were done, only 1-2 tenths of charge burns leaving 8-9 tenths, unburnt in chamber.

Jim Jarvis high altitude testing & results: I was the "other flyer" who sent the plastic vials. I was doing some testing of my own 'caveman' style. After placing plastic vial's into airframe on ground, I was amazed at the sharp, jagged pieces of plastic remaining and knew there had to be a better solution. {same plastic as vials that so many use now with flip lock lids, scares me}
View attachment 337848

This validated what I already knew, [not to that extent however] but shocked us with how little actually burns, due to cold & pressure non transfer of heat between BP particles.
If any of you who live in the cold North, ever lit a plain ole strike match below freezing, has seen how slowly the head burns with very little flame. Translate this same phenomena to our ejection charges at higher altitude where temps can be in the -30 to -75 range and lower.

Yes for normal sport flying a NON-ISSUE.....BUT many of the non initiated, are beginning to fly these 2-stagers & minimum diameter projects over 20,000.

My mate Nic's version used inside a 7-1 cone [3ft long]for his 63,000 ft flight.
Av-bay is in tip of cone with barrels pointing back. 12in. long if memory serves. Screws hold sled in place going through NC in 3 points. There is an aluminum ring where screws attach. See post down bit with side view of assemblies.
Quite Xtreme & not needed, [by me] but they work for him and that's what he uses on everything he does.


DSCN4013.jpg DSCN4026.jpg


Just trying to make folks aware of some of these issues they will encounter. No vendor I know of is making these available, so they would serve those doing these type flights if they were.
I suppose a poll maybe in order to sort out the demand.
I do know many, in the same boat as myself, make & use them.

They work....we use them...'nough said. :smile:
Edit: almost forgot...there are other methods [as always] but this one works for me!
 
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..Apogee charges blowing down into the sustainer and main charges blowing up would be different...

It has always been my belief that pressures in the airframe equalize particularly when using shear pins or even tape and that there is really no substantive pushing up or down unless the laundry itself is so tightly packed that a pressure differential forms behind.

I've got no qualms about being proven wrong here, but anecdotal evidence won't be convincing. :)
 
It has always been my belief that pressures in the airframe equalize particularly when using shear pins or even tape and that there is really no substantive pushing up or down unless the laundry itself is so tightly packed that a pressure differential forms behind.

I've got no qualms about being proven wrong here, but anecdotal evidence won't be convincing. :)

+1!!!!!!

The number one issue/complaint I had when designing head end deployment for nosecones was "it will just jam the main into nose-cone & never deploy"
I knew from the get-go it isn't so. Those having problems, didn't know how to pack a chute & were jamming it in too tight.
Ya never have that happen with apogee jamming gear in fin-can. The payload acts like a piston and pulls it out also.
Same with NC.

I'm with you on this.
 
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My mate Nic's version used inside a 7-1 cone [3ft long]for his 63,000 ft flight.
Av-bay is in tip of cone with barrels pointing back. 12in. long if memory serves. The tip actually screws into a receiver on the sled, holding it in place.
Quite Xtreme & not needed, [by me] but they work for him and that's what he uses on everything he does.


View attachment 337852 View attachment 337853


Thank you, Jim, and Mendal.



I am curious why there are three barrels on the bulkhead near the AARD? The 2 long, and one short...
 
Thank you, Jim, and Mendal.
I am curious why there are three barrels on the bulkhead near the AARD? The 2 long, and one short...

Nic used single break for DD. ARRD is used to release the main, long barrels for apogee/drogue.
If I remember correctly the 3rd small barrel was back-up for the main, in case after being released it stuck in the nosecone.
Everything is packed in the nose for his application.

Here are better view of his 3in. versions:
1 copy.JPG
 
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+1!!!!!!

The number one issue/complaint I had when designing head end deployment for nosecones was "it will just jam the main into nose-cone & never deploy"
If anyone is afraid of jamming the laundry into the NC, here's what I do. I put my charge (latex glove fingertip) on a long ematch in the tip of the NC so it will blow the laundry out of the cone.
 
For HED, I attach my main chute to the AV bay, then make sure the charge is sufficient to get the cone off of the chute. Gravity does the rest. Chute can't be jammed into the NC, because it isn't attached to the NC. :wink:
 
Congrats Manny, its a thrust plate.
27787544_1549867315126482_1130975763_o.jpg27787526_1549867341793146_1178653564_o.jpg
I made these mostly by taking two big plates of aluminum, having a 4 year old dip them in Kevlar and epoxy and then grinded it with an angle grinder until they looked like a thrust plate.

-Casper
 
Your process overview leaves me....confused?

I agree, but I think its a snarky remark to the removal of the kevlar from the fins that Manny and Jim did earlier in the build
 
Great build and really appreciate you guys sharing.
This is so core to the magic that gets anyone in love with building & flying rockets.
 
Nose cone fitting...SUCCESS!!!!!

It was bad, but could have been worse. I pulled a couple "old school ways" out of the bag.

60 grit in front of "gravel carbide bits" floor sanding paper we used [16 grit]. This stuff does NOT wear out on fiberglass it will cut your hand if glanced across it. Grit is as sharp as carbide new circular blade.Perfect for hogging off material.
Heavy gloves needed to hold when sanding if you want any skin left. This stuff does the job.
Remember this is a 12in. diameter cone for those just dropping in.

DSCN0636.jpg DSCN0637.jpg

12 in. wide buy it by the foot at paint stores [ask it's in the back for pro's] or at floor refinishing supply/rental. Cut in half.. [about 2.5 ft long 6in wide.]

Pound in CR to keep shoulder round during process.
First with pencil draw random lines on shoulder, this keeps you "honest" during sanding. Go all the way around till lines sanded off. Keep repeating lines-sand off till it fits. First with palm sander, then "shoe shine" it all evenly with long strip of floor sanding paper, so there are no flat spots.

DSCN0638.jpg DSCN0643.jpg




I held cone on table while Manny shoe shined the cone, today he had to do it all by himself.
This was several day process, an hour here,---hour there. Kill you if tried all at once.
We were EXTREMELY surprised how much wall thickness was left, no need to glass a paper thin shoulder. He must of got a better one, thickness wise, it was still a bitch to sand/fit.
Any how it now fits VERY NICELY!!!!:smile:

DSCN0644.jpg

Primed Bondo'd, sanded, primed, spot filled, primed etc. ...prepped fin can. took 2 rattle cans per coat of primer & finish so far. Looks pretty dam good too! Glued in coupler and mounted "doorknobs" [unistrut buttons] Pictures tell the story.

DSCN0619.jpg DSCN0622.jpg

DSCN0624.jpg DSCN0627.jpg

DSCN0629.jpg


Tested Missleworks GPS in park getting close. launch this weekend Talladega!

16 gram charge holders arrived from Rocket Junkies...nice.
 
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...Tested Missleworks GPS in park getting close. launch this weekend Talladega!

Folks excited about seeing this, said a little prayer for you guys, sounds like we'll be able to smell the curing paint from the flight line. :wink:

Which Missile Works GPS are you using?
 
Nose cone fitting...SUCCESS!!!!!

It was bad, but could have been worse. I pulled a couple "old school ways" out of the bag.

60 grit in front of "gravel carbide bits" floor sanding paper we used [16 grit]. This stuff does NOT wear out on fiberglass it will cut your hand if glanced across it. Grit is as sharp as carbide new circular blade.Perfect for hogging off material.
Heavy gloves needed to hold when sanding if you want any skin left. This stuff does the job.
Remember this is a 12in. diameter cone for those just dropping in.

View attachment 338364 View attachment 338365

12 in. wide buy it by the foot at paint stores [ask it's in the back for pro's] or at floor refinishing supply/rental. Cut in half.. [about 2.5 ft long 6in wide.]

Pound in CR to keep shoulder round during process.
First with pencil draw random lines on shoulder, this keeps you "honest" during sanding. Go all the way around till lines sanded off. Keep repeating lines-sand off till it fits. First with palm sander, then "shoe shine" it all evenly with long strip of floor sanding paper, so there are no flat spots.

View attachment 338370 View attachment 338371




I held cone on table while Manny shoe shined the cone, today he had to do it all by himself.
This was several day process, an hour here,---hour there. Kill you if tried all at once.
We were EXTREMELY surprised how much wall thickness was left, no need to glass a paper thin shoulder. He must of got a better one, thickness wise, it was still a bitch to sand/fit.
Any how it now fits VERY NICELY!!!!:smile:

View attachment 338372

Primed Bondo'd, sanded, primed, spot filled, primed etc. ...prepped fin can. took 2 rattle cans per coat of primer & finish so far. Looks pretty dam good too! Glued in coupler and mounted "doorknobs" [unistrut buttons] Pictures tell the story.

View attachment 338373 View attachment 338374

View attachment 338375 View attachment 338376

View attachment 338377


Tested Missleworks GPS in park getting close. launch this weekend Talladega!

16 gram charge holders arrived from Rocket Junkies...nice.


Hey, I'll be at that launch this weekend!
 
Are you still planning to launch this rocket at the PMW "Sky Jam" event this weekend in Central Alabama? Weather isn't looking great but I do plan to attend with a Sony FS-7 4K camera capable of shooting 240 FPS slow-motion, and several Go Pro 6's. Hoping to get some great video of the event.

Facebook page doesn't much information yet.
 
Jim, did it ever launch? Any pics?

I was in Gatlinburg over the weekend with a terminal friend [why I could not make the launch.] Quick call from Manny....no launch. Will post details when I get them.
I was driving when called, normally I refuse to answer/talk on phone. I answered just long enough to hear "NO GO".
I am disappointed tremendously , as is the rest of crew.
 
Weather was the issue. Windy conditions and relatively low ceilings for most of the weekend. Sunday was great until around 2PM when the rains came. In typical Alabama fashion, it's beautiful today with temps hovering around 80 degrees.

PMW does have another launch scheduled for March--maybe the big rocket can make a return trip?
 
Weather was the issue. Windy conditions and relatively low ceilings for most of the weekend. Sunday was great until around 2PM when the rains came. In typical Alabama fashion, it's beautiful today with temps hovering around 80 degrees.

PMW does have another launch scheduled for March--maybe the big rocket can make a return trip?


That's too bad. But he wouldn't want his big motor flying off into the trees either.

I may have to drive down there next month if he brings it out. (I got to see his bulkheads firsthand, man those are big)
 
Any pictures of the finished rocket available?


Sent from my iPhone using Rocketry Forum
 
I covered Sky Jam for Classic Orbit and will post my coverage just as soon as I get it edited. Manny and Steve had reached out to me to cover their launch and I was excited to do so unfortunately, the weather killed our plans. I have extensive coverage of them setting up and look forward to finally getting some flight video so, I can tell their story. As always, I’m grateful to the amazing crew at Phoenix Missile Works for allowing Classic Orbit to cover their launches and I encourage anyone who wants to go fly down there to please, check it out!

IMG_0302.jpg

www.classicorbit.com

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I was in Gatlinburg over the weekend with a terminal friend [why I could not make the launch.] Quick call from Manny....no launch. Will post details when I get them.
I was driving when called, normally I refuse to answer/talk on phone. I answered just long enough to hear "NO GO".
I am disappointed tremendously , as is the rest of crew.


Excellent build thread. Very interested to read how your flight goes.

Bob Clark
 
I could not go due to my health issues...BUT just got off the phone with Manny! It just flew minutes ago.

Motor was awesome, weather great & calm. They were on the way out, in middle of field to recover.
Will have details later.

Nike held together just fine!:y:
 
Congratulations! I was just talking to Charlie yesterday. Told me you might be going to Bayboro, looks like i'm missing out again. Can't wait for the pictures.
 
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