Fiberglass nose cone limits

[Cameron Anderson]

Just curious what the limits are for commercial FG nosecones in terms of speed.
Does diameter make a difference? Are 3" stronger than 4"? Does brand matter? Are RW/CW better or worse than Wildman? Are VK stronger than standard ogive?

 

[Steve Shannon]

Going through the air? Strength isn’t really an issue. I’ve never heard of a fiberglass nosecone breaking while flying.
Overheating the tip, yes, especially if the tip is sharply pointed because that causes a greater concentration of heat.

 

[Hobie1dog]

stay away from CW as you've likely read all the posts about them.

Comparison of drag characteristics of various nose cone shapes in the transonic to low-mach regions. Rankings are: superior (1), good (2), fair (3), inferior (4).

 

[Hobie1dog]

Read this article as you will find it interesting:
https://www.irjet.net/archives/V7/i8/IRJET-V7I8605.pdf

 

[JackC]

Just curious what the limits are for commercial FG nosecones in terms of speed.
Does diameter make a difference? Are 3" stronger than 4"? Does brand matter? Are RW/CW better or worse than Wildman? Are VK stronger than standard ogive?

Wildman sells a VK nosecone that is made for Mach 1.5 to 2.5. The cone is made from high temperature resin designed to take 200 degrees Celsius. He has them in 54mm, 3 inch and 4 inch. I use the 3 inch on a carbon fiber minimum diameter rocket designed to reach Mach 2.3.

 

[Cameron Anderson]

Wildman sells a VK nosecone that is made for Mach 1.5 to 2.5. The cone is made from high temperature resin designed to take 200 degrees Celsius. He has them in 54mm, 3 inch and 4 inch. I use the 3 inch on a carbon fiber minimum diameter rocket designed to reach Mach 2.3.

This is the kind of info I'm after. I'm curious who has pushed which nosecones the hardest and fastest without shredding.

I've had my Wildman Mach 2 live up to it's name on an L1000 and K455 with no issue.

I've had a RW 4" nosecone to Mach 1.7-1.9 on a variety of motors...again, no issue.

I've had several RW 2.6" nosecones high mach 1 more times than I can count.

But these are max velocities...the rocket was only supersonic for a matter of seconds. And they aren't truly that fast. I'm talking sustained mach 2 to Mach 4.

Is the metal tip and associated aerodynamic heating truly the weak link in the nose cone chain? I've read plenty of stories here about nose cone failures at high speed...what causes them, is there a speed limit, could replacing the aluminium top with a composite fix the failure issue?

 

[JackC]

This is the kind of info I'm after. I'm curious who has pushed which nosecones the hardest and fastest without shredding.

I've had my Wildman Mach 2 live up to it's name on an L1000 and K455 with no issue.

I've had a RW 4" nosecone to Mach 1.7-1.9 on a variety of motors...again, no issue.

I've had several RW 2.6" nosecones high mach 1 more times than I can count.

But these are max velocities...the rocket was only supersonic for a matter of seconds. And they aren't truly that fast. I'm talking sustained mach 2 to Mach 4.

Is the metal tip and associated aerodynamic heating truly the weak link in the nose cone chain? I've read plenty of stories here about nose cone failures at high speed...what causes them, is there a speed limit, could replacing the aluminium top with a composite fix the failure issue?

The Wildman HT nosecones are fine for sustained Mach flight up to Mach 3. Anything above that, guys who fly at those speeds use a composite tip and an ablative coating. You should inquire to FredA on this site. He does stuff like this a lot.

 

[Adrian A]

Going through the air? Strength isn’t really an issue. I’ve never heard of a fiberglass nosecone breaking while flying.
Overheating the tip, yes, especially if the tip is sharply pointed because that causes a greater concentration of heat.

I imploded a homemade CF nosecone once, around Mach 2.5. It was very, very thin and used Aeropoxy resin. Not sure if I have a picture but it looked really funny afterwards, like a cartoon exploded cigar.

 

[plugger]

A standard epoxy FWFG nose cone will stand up to a Mach 3 flight just fine. Here's a Composites Warehouse (I think) NC that I flew that sheared off the vehicle just before Mach 3. It went sideways at that speed and didn't implode. You can see a the base of the NC where the filaments were stressed from the event and even they didn't let go.

 

[JackC]

A standard epoxy FWFG nose cone will stand up to a Mach 3 flight just fine. Here's a Composites Warehouse (I think) NC that I flew that sheared off the vehicle just before Mach 3. It went sideways at that speed and didn't implode. You can see a the base of the NC where the filaments were stressed from the event and even they didn't let go.

View attachment 543449

O…kay, I think the case has been made for a high temperature nosecone…

 

[plugger]

O…kay, I think the case has been made for a high temperature nosecone…

More like the opposite? It didn't even lose it's rattle can paint, much less get to the point where the epoxy would soften. Homemade FG nose cones have been fine up to M3.5, which is near the limit of what can be achieved with cots reloads.

 

[tfish]

One of the key points is securing the alum tip..if so equipped. Especially the tips that do not have a shoulder built into them. The Alum expands as it heats up....then becomes lose ..possibly allowing mach whatever..to enter the nose cone..then things go bad.
Not a nose cone point..but lots if these rockets fold up just in front of the motor case. Its east to sleeve it up to the nose cones shoulder.

Things are fairly easy up to 2 7 mach..

Tony