What was the deal with Estes Big Daddy nose cones?

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mikec

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Drag separation requires both the body of the rocket to be very draggy and the nose cone to be comparatively heavy, and the latter doesn't seem to be the case with a stock Big Daddy.

I continue to believe that weak ejection charges are the most likely cause. Maybe the shape of the shoulder contributes a little, but I have had my share of deployment failures without such factors.
 

georgegassaway

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George, I like this method - have you ever had issues with the chutes tangling?
Nope.

The chutes are located far enough apart along the shock cord, and the nose section "drogue" chute gets out and usually begins to open before the main gets out even if it is ejected rather than being pulled by the drogue.

Been using it since 1980.
 

MALBAR 70

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The main reason for my modification was due to an E12 cato that literally blew the bottom out of the nose cone. As I was building another Big Daddy at the same time as the repair, I modified both cones at the same time.
I lost my first Daddy to a lawn dart,it was either a weak ejection or the dreaded blow by. I never found the rocket, so I'm not sure what happened. Before that I had a dozen or so flights on it without a problem as well as the other BD before the cato.
 
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Tom

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I have another theory, although not founded in evidence.

Possibly since the nose cone has that angled tilted section when the pressure wave hits the nosecone it might kind of tilt it to one side. More pressure on one side than the other causing it to 'wedge' at an angle and not come out.

Just a thought.
 

rharshberger

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Everyone needs to read Steve Kristals response to this same subject/question over at Facebook, I will not repost it without Steve's permision, but I will post the link to the statement he made. FYI I have in the past been guilty to believing somewhat in the sloped shoulder causes an issue, not so much anymore (but not entirely denying it COULD be part of a problem depending on specific situations). Another good read in the same thread is Matt Steele's response, Matt is the designer of the nosecone and it has been used for over 20 years on North Coast Rocketry products.

https://www.facebook.com/groups/225...39973318603&notif_t=feedback_reaction_generic
 

Ez2cDave

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Has anyone 3D printed a replica NC without the slope? If so, I’d be interested in the file.
What about just 3D printing the "missing piece" ( ABS plastic ? ) and gluing it in position to "restore" a Full-Shoulder to Nose Cones with this type of "Bevel" ?

BTW - There are MANY Nose Cones that have this shoulder design.

Dave F.

PLASTIC NOSE CONE ISSUES -01.jpg



PLASTIC NOSE CONE ISSUES -02a.jpg



PLASTIC NOSE CONE ISSUES -03.jpg
 

o1d_dude

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I’m going to go with weak ejection charges.

That being said, I usually cut off the bottom of plastic nose cones and install a plywood bulkhead to support the eyebolt and add nose weight as needed. This technique also allows for more room in the body tube for recovery materials. If the nosecone material doesn’t play well with epoxy, I drill holes through into the bulkhead and screw it in place. I have also used bamboo skewers inserted through the tip of the nose cone before adding in epoxy/lead shot mix for ballast. Trim the protruding skewers and Bob’s your uncle.

That’s my story and I’m sticking with it.
 

PatD

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I’m going to go with weak ejection charges.

That being said, I usually cut off the bottom of plastic nose cones and install a plywood bulkhead to support the eyebolt and add nose weight as needed. This technique also allows for more room in the body tube for recovery materials. If the nosecone material doesn’t play well with epoxy, I drill holes through into the bulkhead and screw it in place. I have also used bamboo skewers inserted through the tip of the nose cone before adding in epoxy/lead shot mix for ballast. Trim the protruding skewers and Bob’s your uncle.

That’s my story and I’m sticking with it.
Funny. Bob IS my uncle. :cheers:He drinks a lot of beer, or used to anyway.
 

Back_at_it

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I will be receiving a new Big Daddy kit to work on soon to help fight off boredom :D

But I remembered there was some sort of issue with the nose cone of this model.

I did a brief search and found lots of 'yes I modded my nose cone' but no real examples of what was actually done.

Thanks in advance :D

After two partial ejection failures where the nose cone popped but didn't hang the laundry and two lawn darts on two different Big Daddies I looked at the nose cone and it was clear without doing research that the slope in the nosecone was the issue. I came to the same solution as MALBAR and cut the shoulder of the nosecone down to remove the angle part. From there I epoxied in a bulkhead made from hobby grade plywood with an eye bolt. If you cut the bulkhead slightly oversize it will sit on top of the notch for the shoulder and will be mechanically impossible to pull out of the nosecone so you don't use a ton of epoxy.

The plus side of doing it this way is you gain approx 3 inches of very much needed space inside the body. If you go the route of simply gluing a bulk head to the bottom of the cone you will have the same effect but you lose even more of that space inside the body for The laundry. you might actually lose a tiny bit of weight but I didn't weight the nosecone before and after.

At the end of the day. I went from having 2 almost failures and 2 complete failures to having 20+ flights on my Big Daddies without a single failure. The pics below are from the build when I was trying to explain to a friend what i was changing.

Someone also mention the Bertha nosecone with it's cone like bottom. I do the same thing to that cone as well.
nc1.jpg
nc2.jpg
 
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McKeon

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We had a great launch in Midland, NC this past weekend and after one successful Big Daddy launch I then had two consecutive Big Daddy lawn darts. Both lawn dart motors were older (date code was 04 05 04) but both also had an ejection charge go off based on the charred wadding sheets that were still in the rocket. Based on that I thought the ejection charges just weren’t strong enough to do their job. I didn’t really think the motors’ age was the issue because I know lots of folks use old motors (myself included) with success, and my motors are stored in friendly conditions. My first successful flight was a newer motor and the two lawn darts were from a 3-pack I just opened that day (but had been sitting in my range box for about 16 years) so I couldn’t shake the feeling the issue was related to the motors. I have launched many different Big Daddys through the years and never had this issue. I have launched this particular Big Daddy seven times and the only problems were those two lawn darts.

So, the first thing I did when I got home was search for this issue on TRF and here we are. Obviously this thread has me thinking the root cause was blow-by due to the design and that the motors are INNOCENT! I plan to modify my nose cone and launch the third motor from the same package and see what happens. Unfortunately, I can’t launch the third motor in the same Big Daddy because the second lawn dart hosed up the body tube and motor mount, but I will use the same nose cone (modified) and see what happens.
 

K'Tesh

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We had a great launch in Midland, NC this past weekend and after one successful Big Daddy launch I then had two consecutive Big Daddy lawn darts. Both lawn dart motors were older (date code was 04 05 04) but both also had an ejection charge go off based on the charred wadding sheets that were still in the rocket. Based on that I thought the ejection charges just weren’t strong enough to do their job. I didn’t really think the motors’ age was the issue because I know lots of folks use old motors (myself included) with success, and my motors are stored in friendly conditions. My first successful flight was a newer motor and the two lawn darts were from a 3-pack I just opened that day (but had been sitting in my range box for about 16 years) so I couldn’t shake the feeling the issue was related to the motors. I have launched many different Big Daddys through the years and never had this issue. I have launched this particular Big Daddy seven times and the only problems were those two lawn darts.

So, the first thing I did when I got home was search for this issue on TRF and here we are. Obviously this thread has me thinking the root cause was blow-by due to the design and that the motors are INNOCENT! I plan to modify my nose cone and launch the third motor from the same package and see what happens. Unfortunately, I can’t launch the third motor in the same Big Daddy because the second lawn dart hosed up the body tube and motor mount, but I will use the same nose cone (modified) and see what happens.
Sorry to hear about the damage to your rocket.

Did you have any tape wraps around the shoulder to make the fit tighter?
 

McKeon

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No tape but the fit was quite snug. Since the Big Daddy is one of my favorite kits I have a bunch ready to build so I am planning to do one with the standard motor mount and another with a 29mm motor mount. I’m working my to an “Angry Daddy” and that one is a beast!
 

K'Tesh

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Here's the latest theories I have to the problem with this (and soon we may find the DBRM to be included with this). Originally posted on FB as a reply to this comment.

I posted this:
Another Estes Big Daddy (2162) Lawndart Questions Thread...


Some question that aren't in the thread, but I'd like to get the OFFICIAL (read: from ESTES) answers to... What is the definition of "Too Loose"? What is the definition of "Too Tight"? I have my own ideas*... But what are the real answers?

*My ideas:
Too Loose? Does the rocket slip back, or fall apart when picked up by the nosecone? Yes? It's too loose.

Too Tight? Can you not get the nosecone on the rocket w/o damaging the rocket? Can you not "eject" the nosecone by blowing a puff of air from the engine tube into the rocket? Yes? It's too tight.

A good fit would have the nosecone stay attached to the body tube without slipping, yet a puff of air blown into the rocket should get it to separate cleanly.


To which I got this message:
Enquiring FB poster said:
How will a slightly loose nosecone cause a problem?

To which I replied:
It's kind of like a cannon or a musket. If the cannonball or musket bullet isn't well sealed, the charge will not be able to fire it (or fire it as far as it should). You'll get more of "FFFFffffffttt" than a "BOOM!!!"

We've seen videos showing the ejection coming out of the side of the nosecone, just before the rocket arched over and lawndarted. There's another photo showing another BD just before it impacted the ground with the white of its shoulder exposed above the body tube.

As I see it, there are three parts to this problem...

The shape of the nosecone, the weight of the rocket, and experience.

The problems with this nosecone's shape are twofold. Due to its design or manufacture, it is too loose for the 3" OD body tube it is shipped with. I suspect the reason for the looseness is that perhaps Estes was going to ship it at some time with a heavier walled body tube, or anticipated people would use it with other available 3" tubes that are thicker walled than theirs in scratch building. The other problem is that "ramp" that creates the attachment point. If the attachment point was done with a smaller slope, there wouldn't be a "ramp", and thus no way for the ejection to be vented if the rocket drag separates a bit in the coast phase. Which leads us to the second part of this problem... Weight.

The BD is a very lightweight rocket for its diameter. It has large, kinda thick balsa fins. As such, it's also draggy. If the nosecone's fit is loose, then the body tube can separate some from the nosecone opening up that "ramp", turning it into a vent. Which leads to a bad event. Imagine throwing a small rock with a crushed up ball of paper (that is the same diameter) very lightly stuck to it. Then throw them together. The aerodynamic forces will make the paper try to pull away from the rock(et?). Do that again with a rock and a piece of wood instead of the paper. You won't get the same reaction the since the mass difference between the parts is less. Other rockets that use this nosecone are heavier, and so, they are less prone to drag separation.

Then there's the experience issue. There are a lot of veteran BD owners that say that there is nothing wrong with it built "stock". I suspect that what is not being accounted for by them is their experience. They know what a loose nosecone is, and how to fix it with masking tape, as it is shown in the instructions. Thus their "stock" build has a snug nosecone that won't have a problem with drag separation. I believe that less experienced builders *MISS* that instruction when building their rockets, and not knowing that their nosecone is too loose, send it up, only to see it fall out of the sky. I've seen photos of lawndarted BDs show one or more kids staring at the rocket sticking out of the ground. I wonder how many of those kids were the builders? How much experience do they have? Did they add tape to the nosecone as per the instructions?

1611561855397.png

photo: Dave Lang
 
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Back_at_it

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This thing has been beat to death so many times. There is clear proof that the nose cone design is the issue. As stated, there is video proof of the issue. The design allows the nosecone to vent the pressure before it pops. In the video in question, there was no drag separation. The cone was clearly in the tube until ejection. The rocket was at apogee so there was no vertical forces acting on the cone to prevent it from ejecting.

In all of the big daddies that have built, I have never come across the nosecone that the fit is too loose. They have all been tight. If you go back to my previous post #39 and look at the shoulder of the nosecone you can see that a substantial amount of plastic was removed just to get it in the tube.

Long story short, If you feel that the nosecone isn't an issue then by all means build and fly it stock and deal with the issues when they come up. If you want an ounce of prevention then chop the nosecone and insert a bulkhead and be done with it. The choice is yours as you are the builder.

I know of two clubs now that won't all that nosecone to fly unmodified.
 

K'Tesh

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Would you mind sharing with us the names of the two clubs?

Thanks!
 
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