Has anyone tried these

[mpitfield]

I have always liked the classic look of a bell but I am concerned about robbing the motor of performance due to the Krushnic effect.

Has anyone tried these? https://www.rowesretainers.co.uk/38mm_cone_retainer.htm

 

[Banzai88]

I have used one of these to good effect, similar design.

https://giantleaprocketry.com/produ...rs_adapters.aspx#Bell-Shaped_Nozzle_Retainers

 

[jd2cylman]

I have always liked the classic look of a bell but I am concerned about robbing the motor of performance due to the Krushnic effect.

Has anyone tried these? https://www.rowesretainers.co.uk/38mm_cone_retainer.htm

I have one that I removed from a purchased rocket and am sending it back to the original owner. I just prefer the speed of the AeroPack retainers.

Adrian

 

[dhbarr]

The bell retainers shouldn't krushnic or hibachi, but you will get some added drag on the tail.

 

[mpitfield]

I have used one of these to good effect, similar design.

https://giantleaprocketry.com/produ...rs_adapters.aspx#Bell-Shaped_Nozzle_Retainers

If you look close enough at the rocket in my Avatar you can see the 38mm silver GLR bell retainer. I love it and love the look. I also have a black 54mm one but have hesitated on using it until I can get a clearer picture on what if any effect it has on motor performance.

What started this for me was the RockSim I used for that rocket ended up being way off, about 60% off from the actual flight, and that is an anomaly based on the rest of my simulations. My simulations are usually within 15-20% for the first sim then I adjust the sim post flight based on actual numbers and continue to adjust with each flight to where they are reliably within 5-10% depending on the velocity and alt.

Based on this, the obvious difference between this rocket and the rest of the fleet is the bell retainer. However in all fairness I have only launched this rocket once so it is premature to call it. The rocket had an experimental deployment system that I rebuilt last winter to a traditional recovery system, but I have not launched it since, and may not until next spring in order to get some comparable numbers.

 

[Onebadhawk]

Michael how does that one from the UK work ???
You have to put wood screws into the aft centering ring each time ???

Teddy

 

[mpitfield]

Michael how does that one from the UK work ???
You have to put wood screws into the aft centering ring each time ???

Teddy

Hey Teddy,

I was wondering the same thing and had the same thought as you. Not as slick as the GLR one, however if it is a removable one then at least it's not permanent if you have issues with it. So it may be a good one to test.

 

[Onebadhawk]

EEhhhhh,,
Looks like the bell gets in the way of the screwdriver shank....

Teddy

 

[JJSR]

I have a GLR 38mm one on my up-scale QCC explorer, love the look, as for performance I don't know

 

[RocketFeller]

I want one!

I have two rocket with the Binder Design bell (one is the Galaxy that they are made for, the other a scratch build) and I like the look lot. I am an anti-performance kind of flyer usually, so I don't mind the extra drag one bit.

 

[MikeyDSlagle]

With the way that cone is made, it would be a PITA using screws all the time. It looks like maybe the base is attached via screws and the cone threads on and off, like the bigger aeropacs. The 24mm is made that way for sure, so I would think surely the larger ones are too.

 

[Banzai88]

Michael how does that one from the UK work ???
You have to put wood screws into the aft centering ring each time ???

Teddy

Hey Teddy,

I was wondering the same thing and had the same thought as you. Not as slick as the GLR one, however if it is a removable one then at least it's not permanent if you have issues with it. So it may be a good one to test.

EEhhhhh,,
Looks like the bell gets in the way of the screwdriver shank....

Teddy

I'm trying to find the pics that I've seen of them, but IIRC, you put threaded inserts into the aft centering ring, and use an L shaped allen wrench on the short side to turn in allen headed screws to hold it on. Not the most user friendly, and why I decided to use the GLR unit.

 

[neil_w]

What is the white rocket in the second picture?

 

[Bat-mite]

Other than looking nice, I am not seeing any benefit.

 

[Banzai88]

What is the white rocket in the second picture?

From the Rowes site: Gary Blinko with his scale Pegasus. The cone will be painted white to match the rest of the model

 

[Onebadhawk]

I'm trying to find the pics that I've seen of them, but IIRC, you put threaded inserts into the aft centering ring, and use an L shaped allen wrench on the short side to turn in allen headed screws to hold it on. Not the most user friendly, and why I decided to use the GLR unit.

Yeah Tom,, that's what I was seeing,, your pic's are better though,,
but threaded insert or not I still think Giant Leaps is easier by far to get on and off....

Teddy

 

[Banzai88]

.......but threaded insert or not I still think Giant Leaps is easier by far to get on and off....

Teddy

I agree 100%. I like my GLR bell, works well, and I would buy it again.

I briefly considered the Rowes, and solving the pain in the butt fastener alignment with a ball allen driver. After going through some serious Olympic grade anal gymnastics to figure out how to get one over here on the US side of the pond, and for the price point, it was a non-starter. I'm at a point in life where my tolerance for 'work arounds' instead of 'works right' is about nil.

 

[Onebadhawk]

I agree 100%. I like my GLR bell, works well, and I would buy it again.

I briefly considered the Rowes, and solving the pain in the butt fastener alignment with a ball allen driver. After going through some serious Olympic grade anal gymnastics to figure out how to get one over here on the US side of the pond, and for the price point, it was a non-starter. I'm at a point in life where my tolerance for 'work arounds' instead of 'works right' is about nil.

hahahaha,,
Man I'm with ya there...
No reason most often right..
Just easier to do it right the first time...lol...

Teddy

 

[manixFan]

Other than looking nice, I am not seeing any benefit.

The look is the benefit. For some designs the bell would really make the rocket.

Why do folks put decals on their rockets? I don't see the benefit in that so I almost never do. But lots of folks like the looks in spite of the trouble and expense.

To each their own.


Tony

 

[Bat-mite]

The look is the benefit. For some designs the bell would really make the rocket.

Why do folks put decals on their rockets? I don't see the benefit in that so I almost never do. But lots of folks like the looks in spite of the trouble and expense.

To each their own.


Tony

Can't argue with that!