What was the deal with Estes Big Daddy nose cones?

[Tom]

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

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

 

[Spitfire222]

I also did similar research as I likewise have a Big Daddy in the pipeline to be built. From what I understand, the giant bevel on the side for the recovery system attachment loop deflects a lot of the ejection charge energy which sometimes prevents the nosecone from fully separating from the body, so the rocket returns ballistic. The fix is apparently to either remove that bevel by modding the nose cone, cutting off the bevel, or attaching a flat plate at the bottom so the ejection charge energy fully impinges on the nose cone parallel with the body to give the full force to remove it and successfully eject the recovery system.

 

[K'Tesh]

Here's my theory, combined with the bevel, the low-mass, high-drag design of the booster causes the rocket to partially "drag separate" after the initial thrust period of the motor ends. Then when the ejection charge goes off, the now vented recovery bay simply allows the pressure to blow past it, and the rocket turns over at apogee, and comes in without the parachute deploying.

A possible fix would be to add tape to the shoulder to tighten up the joint. However, depending on local conditions (heat, humidity, the tape's properties, etc.) this may become too tight (preventing deployment) or too loose (still allowing drag separation). Thus many people opt to mod the nosecone by eliminating the bevel in some manner.

Personally, I plan on cutting away the bottom of my BD's nosecone, and adding in a plywood bulkhead (and possibly a payload/av bay), while still closing the area that the bevel was located. While this will increase the area that the parachute, shock cord, and wadding can be located, it will also decrease the area that the ejection charge has to pressurize (by sealing off the unused volume of the nosecone) and thus increasing the pressure of the ejection charge.

Another possible mod would be to glue (or tape in) some foam (like Styrofoam, or the stuff used for dried floral arrangements*), then shape it to fill the bevel.

*I'd recommend testing any foam for its flammability before doing this.

 

[Spitfire222]

Here's my theory, combined with the bevel, the low mass, high drag design of the booster causes the rocket to "drag separate" after the initial thrust period of the motor ends. Then when the ejection charge goes off, the now vented recovery bay simply allows the pressure to blow past it, and the rocket turns over at apogee, and comes in without the parachute deploying.

Interesting, so that would lead one to conclude that a potential solution is to actually increase the friction of the nose cone to body fit to prevent that drag separation from happening, correct?

 

[K'Tesh]

Interesting, so that would lead one to conclude that a potential solution is to actually increase the friction of the nose cone to body fit to prevent that drag separation from happening, correct?

You replied while I was still editing my initial response. But again, it's a possiblility.

 

[MALBAR 70]

I have modded both of my Big Daddy nosecones (1 old, black and yellow and one newer, red\grey fade) by cutting the sloped part off and epoxying in a plywood bulk plate. I chose to do it this way so I could make more room for the recovery gear and add a Nomex shield as well.

 

[AfterBurners]

I also did similar research as I likewise have a Big Daddy in the pipeline to be built. From what I understand, the giant bevel on the side for the recovery system attachment loop deflects a lot of the ejection charge energy which sometimes prevents the nosecone from fully separating from the body, so the rocket returns ballistic. The fix is apparently to either remove that bevel by modding the nose cone, cutting off the bevel, or attaching a flat plate at the bottom so the ejection charge energy fully impinges on the nose cone parallel with the body to give the full force to remove it and successfully eject the recovery system.

so basically install a bulk plate. I had a BD too had some issues with it, but I'm thinking it was more stability. I had a couple ballistic flights as well. It seems AC rockets is the place to buy. I've been building some 24mm rockets just to save on the wallet

 

[MALBAR 70]

 

[caveduck]

Severe diagonal cutaways on the base of nose cones are a Bad Idea (tm) from an engineering standpoint, for the reasons above - lateral force plus early venting of the pressure before the nose cone is off results in not getting the laundry out. I've also seen the molded-in loops fail way too often. They may be designed that way to allow having the molded-in loop without increasing the length of the mold tooling, which costs $$. Overall I consider those nose cones a safety hazard, and always put a replacement bulkhead on them with a metal eyebolt, much like Mike's picture.

 

[Culprit]

The Leviathan has the same bevel cut on the base of the nose cone, and some folks have reported the same thing on that model. You can search for Leviathan threads to see some examples of fixes similar to what have already been shown here in this thread.

 

[MALBAR 70]

The Leviathan has the same bevel cut on the base of the nose cone, and some folks have reported the same thing on that model. You can search for Leviathan threads to see some examples of fixes similar to what have already been shown here in this thread.

Happened on the maiden flight of my Executioner too.

 

[BDB]

Has anyone 3D printed a replica NC without the slope? If so, I’d be interested in the file.

 

[Tom]

Darn, I dong have any lite ply left around here. Guess I will have to order a sheet.

What thickness would you suggest?

 

[nosecone]

Interesting thread, thanks for the learning experience.

 

[K'Tesh]

Darn, I dong have any lite ply left around here. Guess I will have to order a sheet.

What thickness would you suggest?

3/32" or 1/8" should do. It just needs to be strong enough to hold the nosecone on to the shock cord. The eyebolt or U-bolt will take the strain of the parachute deployment.

 

[Gus]

The problem with the Big Daddy nosecone is a largely theoretical problem. It absolutely won't hurt to add a bulk plate but it's not really necessary. The Big Daddy was designed by Matt Steele to be an alternate use by Estes for the North Coast 3" nosecone, of which Estes had a lot when they discontinued North Coast by Estes. Multiple North Coast models had used that nosecone for years without a problem.

The Big Daddy has been sold almost nonstop now for over 20 years and if the nosecone issue was significant you should see tons of reports here, or on RocketReviews.com. And if there were frequent nosecone ejection failures Estes would've changed the cone by now. Again, if you're concerned go ahead and add something but it's not really necessary.

 

[BEC]

The Leviathan has the same bevel cut on the base of the nose cone, and some folks have reported the same thing on that model. You can search for Leviathan threads to see some examples of fixes similar to what have already been shown here in this thread.

Hmmmmm..... I'm glad I made the top few inches of my Leviathan a payload section...so it is not subject to this.

Steve's point (his post just above) is well taken....but I have seen only a few Big Daddies fly but I have seen at least a couple of ballistic returns.

 

[K'Tesh]

I've just heard too many stories about it... Remember, it only took one kid choking to death on a toy missile from a Battlestar Galactica toy to completely change the entire industry. Model Rocketry has a very impressive history of safety. It seems shameful that Estes continues to even risk that on this one nosecone. I realize that there are a lot of them out there, and perhaps the number of ballistic returns is really low, but I've never seen the volume of other kits using different nosecones with reports of lawndarts. In fact, I seem to remember hearing about some clubs not allowing stock Estes Big Daddy kits at their functions due to its proclivity to lawndart. Can anyone confirm this?

If so, why hasn't NAR and Tripoli as a whole implemented it?

 

[Arsenal78]

Estes has known about this problem for over 20 years now and the reports of it lawn darting because of it but they refuse to fix it. Considering it's been in production for so long and how many reports there have been of this exact issue, they should've gotten a new mold and fixed this issue a long time ago. The NAR and Tripoli (NAR especially) preach rocket safety but still allow the Big Daddy to fly at sanctioned launches.

 

[goose_in_co]

You can extend the motor mount into the nose cone and eliminate all of these issues, It blew off the nose cone with such force that it made an "Estes dent".

I wrote it up on EMRR years ago here:
http://archive.rocketreviews.com/reviews/all/mod_est_big_daddy3.shtml

 

[Trident]

I’m building my first Big Daddy now. I “JB Welded” a thin plywood bulkhead to the base of the nose cone. Pulling on it shows no signs of it flexing the plastic, it’s solid. I did hold the shoulder base up to my disk sander to remove a bit of plastic since it was ever-so-slightly convex. It did not require much plastic to be removed to make the base perfectly flat.

I also extended the motor tube to within about 1/32” of the plywood disk.

 

[rharshberger]

The Leviathan has the same bevel cut on the base of the nose cone, and some folks have reported the same thing on that model. You can search for Leviathan threads to see some examples of fixes similar to what have already been shown here in this thread.

Same nosecone so no surprise.

 

[Steve Shannon]

It’s a slippery slope to start banning rockets because people can’t adjust them to fly correctly.

 

[rharshberger]

Just like CATO's, we are a small community and one single events story gets told by 10 people with no references, so that one CATO becomes 10, in some ways the Big Daddy is that way as well, yes lawndarts happen and often enough the story gets repeated. But I have seen many many BD's flown without issue for every one that did.

 

[mikec]

The Big Bertha plastic cone has a conical base, do you want to ban that too?

I suspect the problem is more with weak ejection charges due to motor variation than anything having to do with the cone geometry.

 

[georgegassaway]

Here's my theory, combined with the bevel, the low-mass, high-drag design of the booster causes the rocket to partially "drag separate" after the initial thrust period of the motor ends. Then when the ejection charge goes off, the now vented recovery bay simply allows the pressure to blow past it, and the rocket turns over at apogee, and comes in without the parachute deploying.

I will note that for various models I've flown where the chute might not get "blown" out by ejection, I use a semi-drogue recovery system. A small chute attached to the nose, and loaded in last (packed so it is a loose fit in the tube), so if the nose comes off at all, it pulls out that small chute. So when that small chute deploys, so at least there is something to reduce the rate of descent. But the main thing is that it can act like a drogue chute to yank out the bigger chute, if the bigger chute is packed loosely enough to be able to slide out. IIRC, I've never had a main chute fail to come out of the tube, if the nose cone got ejected off at all. I pretty much use this method on all my medium to large scale models, and often with other medium to large models. Model below, 2.6" diameter, 6 feet tall.

 

[o1d_dude]

I have seen many BDs fly but have never seen one auger in.

That being said, I’m planning to upgrade a recently acquired BD with plywood C-rings and fins, and a 29mm stove pipe.

Let’s try to keep my record clean.

 

[K'Tesh]

The Big Bertha plastic cone has a conical base, do you want to ban that too?

I suspect the problem is more with weak ejection charges due to motor variation than anything having to do with the cone geometry.

The conic nosecones don't vent in a drag separation situation. If it's separated, it's completely out.

 

[foose4string]

I’ve flown mine with BP and AP several times with no issue. I always check to see if a cone feels too loose or tight when prepping and adjust accordingly. I don’t believe modding the cone is necessary but whatever floats your boat. Certainly doesn’t hurt.

 

[OC-Patrick]

I will note that for various models I've flown where the chute might not get "blown" out by ejection, I use a semi-drogue recovery system. A small chute attached to the nose, and loaded in last (packed so it is a loose fit in the tube), so if the nose comes off at all, it pulls out that small chute. So when that small chute deploys, so at least there is something to reduce the rate of descent. But the main thing is that it can act like a drogue chute to yank out the bigger chute, if the bigger chute is packed loosely enough to be able to slide out. IIRC, I've never had a main chute fail to come out of the tube, if the nose cone got ejected off at all. I pretty much use this method on all my medium to large scale models, and often with other medium to large models. Model below, 2.6" diameter, 6 feet tall.

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