Newbie idea for better chute deployment? Will this work?

Hifin Sword

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I need help. I got into rocketry this past year with my g/kids b/c I thought rockets would be easier than hauling my RC Fixed wing a/c hours away. As far as space in the car it is easier. But getting parachutes to deploy properly seems to be hit and miss.

I'd say about 1 of of 5 times the chute fails to come out properly or in some cases, NOT AT ALL. I built a BIG DADDY and watched it go up and come down HARD AND FAST. Had it hit anyone, things would have been bad. It was in a city park, only my family was there, and it wasn't a close call. But still, you don't want a rocket falling nose first with no chute.

I had already decided to build a BIGGER DADDY using a 2nd body tube and coupler. I thought instead of the parachute charge discharging inside the rocket body, have it vent to the inside the nose cone. That would save any scorching or melting of the chute, and eliminate the chance I packed the wadding too tightly. This I suspect was the cause of the chute not deploying in at least 1 case.

My build has the smaller center rocket engine tube, extended all the way up to the nose cone. The normal exit for the chute charge exhaust just above the rocket motor was fitted with an already used rocket engine that is cut off so that the clay vents the gases. Hopefully that will help keep the hottest gases away from the normal stop piece where the extended tube starts. I also painted the inside of the discharge tube and the bottom of the nose cone with some HIGH HEAT PAINT. I opened the hole in the bottom of the nose cone some to better fit the end of the discharge tube which fits flush against the nose cone now.

Has anyone tried this? Do you think it will work? Any comments on what not to do or any cautions with this setup?
Don
 

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The concensus about the cause of Big Daddy lawn darts seems to be that the slanted portion of the nose cone shoulder allows the ejection charge to vent out before fully blowing off the nose cone and recovery gear. The solution seems to be cutting off the slanted portion and epoxying in a plywood bulkhead with screw eye inside the shoulder.
Numerous threads have referred to this, try searching "Big Daddy lawn darts".
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And welcome to the forum.
 

DigBaddy

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Stuffer tube into the nosecone has been done and works well. Most go for the bulkhead method noted in the post above.

The extra tube you added will probably increase the stability and overall weight of the rocket to where it will want to weathercock more (turn into the wind) and go horizontal, especially on 24mm black powder motors. You may not have good flights on those with the extended chassis and something like the E20-4 may be ideal. A longer launch rod would also help.
 

Hifin Sword

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Thanks kuririn and BigDaddy for your comments. From the little I've read here, the extra tube will move the CG forward and make the rocket more stable. Weathercocking into the wind sounds like a plus. Go upwind on rocket power and drift back downwind to the launch pad. So far I think I've only used the C11-3 Estes rockets and only on the Big Daddy. I don't have the experience to know if that will be enough for my BIGGER DADDY. I prefer to not go too high. My RC club field is out in the country with acres of farmland around it so drifting away shouldn't be a problem. But if it doesn't go high enough due to the extra weight, the chute opening may be too low.

I'll have to give the current setup a try and if I ever need to rebuild, the plywood bulkhead will be the next mod.

One more question. Do you think using the fire-resistant blankets or cloths will help with less scorching of the chutes? Getting the wadding correct seems to be a hard nut for me to crack. Too little and the chute gets scorched. Too much and the chute gets scorched without deploying.
Don
 

DigBaddy

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Yeah, I use Nomex in all 4 of my Big Daddys (BT-80 downscale, 3 original sizes, and 4" upscale). Before I switched them all, making a layer cake of wadding sheets and dog barf (cellulose insulation) worked quite well in the original and I use that approach in other BT-80-sized rockets. Building that stack of flameproof material allowed it to essentially function as a piston.
 

MidOH

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I use a blanket to burrito the chute, and a little wadding. On wider rockets.

On long rockets I just use a baffle. And add more powder if needed.
 

BDB

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Welcome to the BDLDC (Big Daddy Lawn Dart Club). It's a great rocket with one fatal flaw.

Lots of us use cellulose insulation instead of wadding. It's the stuff that you can buy by the bale at Home Depot or Lowes. It's cheap, and you just throw it in by the handful. Around rocketry circles, it's affectionately known as "dog barf."
 

BABAR

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First, Welcome to TRF.

Second, KUDOs on creativity.

not sure I exactly understand your set up. Are you attaching the cone to the outer body tube segment, so the cone and tube slide off forward, and chute wraps around the side? This would kind of be like a modified rear eject, but you would need a forward centering ring fixed to the stuffer that keeps the pressure on the cone to force the body tube off.

if not, you will definitely blow the cone, but the chute better be really loose or the cone won’t pull it out.

regarding packing, for low power rockets, practice pack WITH wadding and chute and nose cone, WITHOUT motor. assuming Your fins let you get your mouth around the tail of the motor mount, if you can’t relatively easily blow the whole thing out (cone, chute, shroud lines, and wadding) it is too tight.

@kuririn is, as usual, right, the Big Daddy has a reputation for lawn darting (there is an ongoing thread, search “show of hands”), and the culprit is usually assumed to be the angled nose cone base.

anyway, hope you get a good flight, please post your results.
 

Hifin Sword

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Yes, BABAR. The nose cone is attached in the traditional manner to the side of the main tube with the long rubber band. Hopefully the cone will pull the chute out as the cone is pushed away from the main body. From what I gather here, I need to get rid of the slant on the bottom of the nose cone. That would be done most easily I suppose, by epoxying a flat disc to the bottom with the hole in the middle for the hot gases coming up from the small center tube to blast the nose cone off.

But the hot gases won't initially be directed at the slanted nose cone bottom. Initially the gases will go directly to the inside of the nose cone. Of course as soon as the nose cone starts upward away from the main body, gases will go everywhere inside the main tube. So a flat disc hiding the slanted body of the nose cone's base would be helpful if the majority of the initial blast's gases exit into the main tube instead of the cone.

I don't understand what you mean by needing a forward centering ring fixed to the stuffer. What is a stuffer? The smaller tube in the center of the main tube in my setup is fixed and sealed all the way up to the top. It is just an exhaust port for the ejection blast at the end of the rocket burn. Gases shouldn't be entering the bottom of the main tube, only exiting at the top into the nose cone. via the hole in the bottom of the nose cone.

The chute will be placed very lightly around the small centered fixed exhaust tube. The chute may need some protection from the hot gases that don't make it into the nose cone. As already mentioned, as soon as the cone starts its departure, hot gases will be vented into the main tube at the top of the main body tube. If I were to cut the hole larger in the bottom of the nose cone, and extend the smaller exhaust tube into the cone, less gas or maybe none, would escape into the main tube. But I don't want to go that route if a simpler setup works.

I will put a few pieces of wadding over the chute, barely placed, not stuffed, over the chute. The wadding will be on top of the chute as seen from the top of the rocket. Any blowback should be minimal once the cone moves upward. That is my hope anyway.

Thanks for the suggestion to try and blow the cone off without a motor in place. I will give it a try.
Don
 

SolarYellow

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You're still going to have the problem that you are pressurizing the area below the nose cone with the angled vent allowing it to depressurize before all the friction has been overcome to separate the cone shoulder from the BT.

The easiest answer is keep construction conventional, but eliminate the angled shoulder. Either cut it off square and glue a flat bulkhead into the shoulder, or cut out the wedge and fill it with an insert to make a full-length, full-diameter shoulder.

Adding a "stuffer tube" and centering ring only as far down in the airframe as you need to fit the parachute and wadding/blanket above it would help by reducing the volume of airframe needing to be pressurized, but I think maintaining pressure all the way until separation of the nose cone is a bigger factor, if you're only going to work on it from one direction.

For a system along the lines of what you are proposing to work better than stock, it would need the inner "stuffer" tube to project up into the nose cone with a close fit of the nose cone around the stuffer, much like a coupler or the nose cone itself in the body tube. Then, you pressurize the inside of the stuffer tube and the internal volume of the nose cone. The effective area working to eject the nose cone would only be the area of the stuffer, not the whole bottom of the nose cone. But with a 24mm tube, that could be enough. Additionally, you could run the stuffer tube far enough up into the nose cone that it continued to be pressurized past the point where the shoulder cleared the body tube, continuing to accelerate the cone away from the airframe. This would help give it the inertia needed to yank the laundry out of the airframe.
 

Hifin Sword

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Babar, I tried to blow off the NC by blowing into the tail exhaust end and only got it to pop off 1 out of 3 tries. I extended the blast tube higher so the bottom part of the NC would enclose it. I had to enlarge the hole in the NC so it would fit. I also added a plywood plate to the bottom of the NC to trap the gases so they wouldn't exit the sides. I should have done only one of those mods, but now it's done. I took the BD to my g/kids 3 hours away 2 weeks ago and gave it a try. I used my most powerful engine, a C11-3. But it wasn't powerful enough after adding all that weight. I should have used maybe a D12 or E-12 but I went with what I have on hand. Thankfully there wasn't any damage due to the ground being soft. Any recommendations on which 24mm engine to use?

If I build another Bigger Daddy, it will use 29mm engines.

 

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SolarYellow

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That barely got airborne, although a D or E might get it high enough for the chute to come out before it core samples the earth again. What does it weigh, all-up? You might be in the land of black powder isn't enough. There are single use composites in 24mm up to F44.

Best solution for motor picking is Open Rocket and try a bunch of different motors for free.
 

Hifin Sword

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Thanks for the Open Rocket mention SolarYellow. I watched a YT video on it here.
It looks like it will take me quite a while to be able to use it competently for the simulations I will need.

The EMPTY weight of my Bigger Daddy is 1 pound. Using a D size motor would add about 1-1/2 oz. An E size motor would add about 2.2 oz and an F size motor would add about 3.6 oz.

I think I will have to use stronger motors. What is more confusing to me than anything is the rocket motors at Estes. When I look at the THRUST numbers for the D, E and F motors, the D motors are running 7.4lbs vs 6.9lbs for the E motors and 5.9lbs for the F motors. Going down in THRUST seems backwards with bigger motors. I'm wondering if the THRUST #s are for initial thrust and not taking into account the BURN TIME. The D motors are burning for 1.6 secs while the E motors are burning for 2.7 secs and the F motors for 2.09 secs. For max lifting power I will need the highest THRUST which seems to be the D motors. But common logic would indicate a E or F motor would be more powerful.

What am I missing here?
Don
 

Hifin Sword

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Good article Big Daddy. Based on the definitions there, the Estes Technical Specs they give as Newtons (N) could be either INITIAL THRUST or MAXIMUM THRUST numbers. Which in my attached spreadsheet still shows the D motors with higher THRUST than the E or F. Obviously that cannot be the case.

After more searching on Estes site I noticed the "Estimated Max Lift Weight" under the Technical Specs. My spreadsheet is now updated with the "Estimated Max Lift Weight" and the motor I will need must be capable of more than the 6 oz thrust C11-3 motor I used last. I included the THRUST #s for the E16-4 and the F15-4 motors for comparisons, but their 29mm diameter eliminates them from consideration.

My thrust tube is 24mm and that will not change unless I rebuild another Bigger Daddy. So any of the D or E size motors will do in the 24mm size. They produce anywhere from 14oz (D12-0) up to 17oz (E12-4). My Bigger Daddy weighs in empty at 1 lb. I'm guessing the 6 oz thrust C11-3 motor I used propelled it to about 50 feet, not high enough. Any suggestions are appreciated.

I am also wondering if the motors ending in "0" means they have no end explosion to push the chute out, or if it just means the delay for the explosion is zero secs. If that is true does that '0' secs delay normally used to ignite a second stage motor just above it?
Don
 

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Steve Shannon

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-# means # seconds after burnout to ejection charge.
-p means the forward end is plugged, no ejection charge.
-0 means there’s no delay and no ejection charge; when the motor reaches the end of its burntime it burns through sending sparks forward to ignite the next stage.
 

Hifin Sword

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-# means # seconds after burnout to ejection charge.
-p means the forward end is plugged, no ejection charge.
-0 means there’s no delay and no ejection charge; when the motor reaches the end of its burntime it burns through sending sparks forward to ignite the next stage.

You probably need an E18-4w or an E28-4 composite motor and a 66" rod

Thanks for the info and suggestions.

Does the E18-4W "reloadable" feature mean I can reload the housing with a new 24mm cartridge from Estes, including C, D or E sizes?

When I went here, https://www.csrocketry.com/rocket-m...tech-e18-4w-white-lightning-rocket-motor.html
it says I need a 12V launch system. I am using the basic Estes 002220 Electron Beam® Launch Controller that uses 4 AA batteries. It only puts out 6V max, 1.5V per AA batt. Seems like I'll need to step up to the 002240 - Pro Series II Launch® Controller with 6 "C" size batts.
Don
 
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Hifin Sword

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You probably need an E18-4w or an E28-4 composite motor and a 66" rod

After searching for more info on the E18-4W it seems just the parts that are sold separately add up quickly to many times the price I see at RocketryWorks.com of $31.39.

At https://aerotech-rocketry.com/products/product_6a315f88-2636-19bb-4a30-9d4e3709ee2f just the AEROTECH RMS-24/40 MOTOR CASE is $27.99. The AEROTECH RMS-24/40 MOTOR AFT CLOSURE is $23.99. The AEROTECH RMS-24/40 MOTOR FORWARD CLOSURE is $24.99. How do they sell the complete motor and 3 reloads at RocketryWorks for $31.39 when the parts go for over $70?

Or am I wrong in thinking I can just buy the E18-4W and have everything I need to launch with it? Do I actually need this Aerotech RMS 24/40 Motor Complete ($65.44) to use the E-18-4W?
https://www.siriusrocketry.biz/ishop/aerotech-rms-24-40-motor-complete-165.html
Don
 

Rex R

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Well you would be buying aerotech reloads (Estes doesn't do composite motors) E20-4 & E30-4 single use motors should also work. Yes a 12volt system is needed either yours or a friend's/ club you might wonder why you waited to get one.
 

Rex R

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The reloads cost $27+ the case is another $30.… Which is why I suggested the single use motors. The rms motors can be fun in Estes rockets though 😄.
 

Hifin Sword

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Because they don't.
So when RocketryWorks.com says this is a Rocket motor, they actually mean it's only the Rocket motor reloads, right? For someone new to the hobby, that's not at all obvious. This is exactly why I am taking the slow path in this hobby, not jumping to the bigger and better thing right away.

I think I'll stay with some higher thrust Estes motors for now. I'm not ready to spend $44 for a 6V launcher and another $90+ for a motor, with 3 reloads to decide if I want to pursue rocketry to higher levels just yet. I think Estes has all I need for now to launch my Bigger Daddy with bigger motors than the C11-3 I was using.

If the Estes D or E motors work in my Bigger Daddy as I hope, I can try the reloadables down the road.
Don
 

DigBaddy

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I would not use Estes D or E motors in that stretched BD. That's now way overstable and quite heavy. Going to weathercock horribly. Maybe could get away with it on a dead calm day. E20/E30 would be my first choice for it.

If you want to fly Estes D/E in a Big Daddy, get another one and build it stock/as light as you can.
 

prfesser

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So when RocketryWorks.com says this is a Rocket motor, they actually mean it's only the Rocket motor reloads, right? For someone new to the hobby, that's not at all obvious. This is exactly why I am taking the slow path in this hobby, not jumping to the bigger and better thing right away.

I think I'll stay with some higher thrust Estes motors for now. I'm not ready to spend $44 for a 6V launcher and another $90+ for a motor, with 3 reloads to decide if I want to pursue rocketry to higher levels just yet. I think Estes has all I need for now to launch my Bigger Daddy with bigger motors than the C11-3 I was using.

If the Estes D or E motors work in my Bigger Daddy as I hope, I can try the reloadables down the road.
Don
FWIW it is easy to build a simple launch controller for 12 volts instead of 6v. It will ignite any common motor starter or cluster of them and is good for up to G motors. Here's some info on redoing an Electron-Beam launch system. You need about 32 feet of 16 gauge or 14 gauge stranded speaker wire ($15) two alligator clips, two "momentary" pushbutton switches or (better) a pushbutton switch and a key switch, a 12 v battery or some sort of battery pack that will provide that voltage or slightly more, and an enclosure for the switches (a $1 "handy box" from Lowes works, and you can get the rest of the items there as well).

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Some way to connect the battery to the wire is needed; some rocketeers will use battery clips that can be connected to a car battery. No, you don't have to remove the battery from the car, just open the hood and attach the clips to the terminals. Others use a rechargeable 12v gel-cell (also at Lowes) or other rechargeable battery.

The "continuity" light bulb is very convenient but not absolutely necessary. Both buttons must be pushed to launch the rocket.

Like I said, it's not hard at all. I built my first 12v controller around age 12.

Best,
Terry
 

Hifin Sword

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Thanks for the idea Terry. My primary hobby the last 10 years has been flying R/C model aircraft. I use 2 cell batts up to 6S (S=cell) LiPos. I only use the XT family of battery connectors, mostly XT60 and XT90s. I need to open up the basic beginner launch controller I bought at Estes and see how I can solder a pigtail for an XT60 conn to it so I can use my model aircraft batts with it. The 3S LiPos charge up to 12.6V. The 4S go to 16.8V fully charged and the 6S charge fully at 25.2V. My smallest 3S is 850mAh, largest is 3300mAh. The smallest 4S is 2200mAh and the largest is 5000mAh.

At STORAGE levels the 4S batts are at 14.8V. I'm OK soldering batt conns so I should be able to solder an XT pigtail to the poles of the battery holder for a LiPo as my power for 12V systems. I think a fully charged 3S, or a 4S at storage level should work.

If I go with the Aerotech line of igniters requiring 12V, I'll have to research them more. I thought I read that some of the Aerotechs use car battery alligator clips for connecting to the igniter plugs. I have detachable alligator clips used with my battery chargers that I can use with 4mm bullets soldered to the speaker wire. I suppose I will have to upgrade the speaker wire to a higher gauge wire. That just leaves the pushbuttons as a weak point. I may have to start the mods with a better Estes controller already fitted for 12V but still use my LiPos.

When at my home turf I would launch rockets at my flying club, and not be able to park close enough to use the car battery. Thanks for the links to the upgrade and speaker wire. Lowe's does all of my Sample Paint matchings for touching up my model airplanes.
Don
 

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