Tired of 3 (or 4!) FNC? Time to pull out the CorkScrew!

[BABAR]

Yup, 1FNC (One fin, one Nose Cone)

For those who want something a little more than the typical beginner rocket, but not TOO difficult to put together, this is your bird.

This was a nice little rocket. I put the formal review here: https://www.rocketreviews.com/corkscrew-1121.html

Cool design, which Odd'l Rockets did a GREAT job of kitting this rocket. No balsa to sand, a "reinforcement guide" which is as close to foolproof as you can get, two launch lugs to assist in a firm bond between the ring fin and the BT-5 body tubes, and for the most part great parts, including good tubes, nose cone, kevlar AND elastic for shock cord.

Instructions are top notch as well.

Construction changes that I recommend:

Put the launch lugs on BEFORE the Body Tube. They are easy to line up using the reinforcement guide, and once they are in place, the body tube will literally fall into place in perfect alignment.

Also, pick your paint scheme before you build. If you want the ring fin a different color from the body tube, recommend you mask the "joint" side of the ring fin and tube, and paint each separately, than glue them together. I discuss this in the review above, it was VERY easy to mask.

Things new to me:

I've never tried electrical tape as a decor item before. If you are going to do "Barber Pole" or other spirals on a rocket, this works GREAT because there is enough "plasticity" of the tape to perfectly mold to the body tube, something I don't think you can do as easily with other tapes. For those wanting to "paint" a spiral, I am wondering if this would work as a MASK? Since there are now several colors of electrical tape available at the hardware store, you are not just limited to black and white.

Boo-Boos I made:
I used Krylon Primer first, and wasn't sure if it would support a lacquer paint, which is ended up using. I sprayed it on in several very light coats and came out well (for me, I'm not yet up to the "glass-like" finish of the "pros" on this forum!)

First flight was on A10-3T motor. I will emphasize this is NOT a recommended motor, but I had a bunch of them, and figured "what the heck?"

So I launched it, and "what the heck?" Or more correctly, "Where the heck is it?" One nanosecond on the pad, next nanosecond 150 feet up. Fortunately I have intrepid Mid South Rocket Society Members who will brave a 6 - 7 foot cornfield to find a little bitty rocket (successfully!)

Later flights with 1/2A3-4T gave a nice corkscrew flight (the intent of the design), perfectly stable, with recovery about 50 feet from pad.

Overall a great design which was "kitted" extremely well.

 

[Barracuda]

Pretty cool Tom! Streamer recovery?

 

[BABAR]

Thanks.

I am a little surprised this rocket isn't more popular. I thought it had great "cool factor", and just by taking out the need for balsa sanding and finishing and aligning and gluing it more than makes up for a technically slightly more challenging build. Put differently, it requires more thought and less actual time and effort than 3FNC. And despite the "screwy" launch path, it gets decent altitude on the mini engines.

Yes, this recovers on a streamer. Good thing, too, cuz this puppy scoots. Things I like about streamers---

1. They come down faster with less drift, so if rocket is light and can handle a harder impact with terra asphalta they are good.
2. They are usually longer than chutes and waggle more in the breeze on the ground, so if you use one of the day-glo colors they make a little rocket easier to spot,

 

[boomtube]

I wonder how much this design can be up-scaled/up-powered before the “corkscrewing” effect makes it unstable or flings it apart.

 

[Sparkytfl]

I have more trouble with filling the body spirals than filling balsa, but the spirals seem like they'd fit right in on this one.

 

[jd2cylman]

I wonder how much this design can be up-scaled/up-powered before the “corkscrewing” effect makes it unstable or flings it apart.

I was wondering the same thing! 4" dia body sounds about right. I got a 7.8" piece of fiberglass coupler that needs a purpose

Adrian

 

[hcmbanjo]

I have more trouble with filling the body spirals than filling balsa, but the spirals seem like they'd fit right in on this one.

If you plan it right, you can cover up any tube spirals with the barber pole tape piece!

 

[hcmbanjo]

Thanks.

I am a little surprised this rocket isn't more popular. I thought it had great "cool factor", and just by taking out the need for balsa sanding and finishing and aligning and gluing it more than makes up for a technically slightly more challenging build. Put differently, it requires more thought and less actual time and effort than 3FNC. And despite the "screwy" launch path, it gets decent altitude on the mini engines.

Yes, this recovers on a streamer. Good thing, too, cuz this puppy scoots. Things I like about streamers---
1. They come down faster with less drift, so if rocket is light and can handle a harder impact with terra asphalta they are good.
2. They are usually longer than chutes and waggle more in the breeze on the ground, so if you use one of the day-glo colors they make a little rocket easier to spot,

Thanks Tom! I appreciate the review and kind words.
It's a very cool looking and flying rocket. I wouldn't have made a kit out of it if there wasn't a "coolness" factor.
One interesting thing about the Corkscrew, it falls at an angle. It tends to land on the lug side (or reinforced side) of the large ring. It's pretty hard to hurt this one!

Streamers are the way to go with most BT-5 models. Like many of the Odd'l Rockets kits, this one is designed for small fields and close to the pad recoveries.
(Except for the Cyclone - you had better launch that one with a 1/2A on the first flight!)

 

[Bone Daddy]

I realize this is nowhere near 4" but..................

I've built a BT-20 and a BT-50 version.

The BT-20 version is one of my favorite rockets to fly.

The BT-20 flies on mini T motors.
The BT-50 on a C6-3 really corkscrews.

Mine are not exact upscales as I built them with supplies on hand.
The tail ring on the BT-20 is BT-80 which is smaller than would be.

The one on the BT-50 I made from sheet styrene.
It's a bit floppy which probably explains the flight pattern.
I scaled it from my BT-20.
https://www.rocketryforum.com/showthread.php?21903-Corkscrew-2x&highlight=corkscrew

I have a BT-60 on the drawing board - actually it's been there for quite awhile.
Maybe it's time to pull it off................................

Bones

 

[boomtube]

What exactly is occurring with this “Corkscrewing”?

Is the body of the rocket staying perpendicular with the direction of flight with the ring causing it to spin around the centerline of the body tube?

Or; is the back end of the rocket going around in circles defined by the ring diameter with the nose describing a much smaller circular motion making the entire of the rocket look like a cone?

I've got to get me one of these.

 

[BABAR]

What exactly is occurring with this “Corkscrewing”?

Is the body of the rocket staying perpendicular with the direction of flight with the ring causing it to spin around the centerline of the body tube?

Or; is the back end of the rocket going around in circles defined by the ring diameter with the nose describing a much smaller circular motion making the entire of the rocket look like a cone?

I've got to get me one of these.

I am pretty sure it is NOT rolling around the rocket body tube axis, as the smoke trail also "corkscrews", which wouldn't happen if it was simply rolling around the body tube axis.

I suspect the axis of rotation goes through the inside of the ring fin, and the body tube motion probably does form a "conical" shape.

What I don't know is how the rocket "decides" which way to spin, clockwise or counterclockwise.

Chris, feel free to chime in here.....

 

[UPscaler]

I was thinking you meant the Estes Corkscrew. But this is a cool kit too!



Braden

 

[hcmbanjo]

I am pretty sure it is NOT rolling around the rocket body tube axis, as the smoke trail also "corkscrews", which wouldn't happen if it was simply rolling around the body tube axis.
I suspect the axis of rotation goes through the inside of the ring fin, and the body tube motion probably does form a "conical" shape.
What I don't know is how the rocket "decides" which way to spin, clockwise or counterclockwise.
Chris, feel free to chime in here.....

Oh -
I wish I had the correct answer for you! I'm no scientist, I'm a banjo player.
I count to four, and repeat.

I would guess (and it is a guess) it has to do with the airflow over the off set tail ring.
The model is trying to "right" itself.
The engine isn't canted - but the airflow over the off set ring pushes the tail end of the body slightly to the side.
With the tail end pushed to one side the ring acts as a vane. The vane (ring edge) is now at a slight angle.
Airflow over the ring edge (now at the angle) makes the corkscrew flight pattern.

If I remember correctly, my models spin counter clockwise as you see them from the ground looking up.

Just a guess on my part. I'm sure someone can do the math and come up with a better answer.