The Predator L3 build

Brent

The fins look great! When are you going to attach them to the motor tube??

After I bevel them and get the aft centering ring & ring above it attached. I figure I could slide it in between the CR's and use your fin jig

Brent

It's impressive that you cut those fins so consistently with a hand jigsaw (in picture -- is that what you used?).

Were all three would plates taped together and cut at once, or were they cut individually?

Nice fins...

Is the "Predator" an upscale of a kit I could see to get the feel of the final layout, or just your name for whatever it's going to look like?

Finally (my own little pitch), my flight line for the Red Glare II launch in Maryland this weekend (driving down from CT today -- weather is predicted to be wonderful):

1. PML 1/2 Patriot with full five motor cluster for the first time. M1315 and 4 x J350. (see www.astralisrocketry.com / Photos-3).

If they all light, it should go 0 - 619 MPH in 4.2 seconds -- better than your average Maserati (and a lot cheaper too!). Expected altitude is 9,700 feet.

2. My new Hawk Mountain Transonic II on K695. Will do 0 - 805 mph in 2.04 seconds and 9,235 feet. (Yes, Brent, "Got Mach and ......")

3. Minnie Magg XL (see Rocketry Forum "Fiberglassing Wood Fins for K-Power" Pages 4 & 5 for photos) on K550 at 350 mph (it's a truck) to 3,805 feet.

Have a fun weekend and look for photos late next week.

yeah, I didn't realize that, I sometimes have a tendency to just look at the pictures rather than read. I am usually guilty of looking at pictures, then replying then reading. I know its bad but I do it and I shouldn't.

David,
It looks like you are going to have a very exciting weekend!! Great looking Patriot, it's got to be nerve racking sending something up that big on that many motors!

Thanks for props on my fins.. I guess I just have a real steady hand. I did cut them one at a time freehand with the jig saw. I just followed the black lines

The rocket itself is of my own design, sorry nothing to give you an idea, unless you want the Rocksim file? That is why I went with the fin design, I figured it was kind of menacing!! arrrghh.. to go with the name.

Brent

I realized when I saw the fins it was no kit, unless you changed the fins on an existing kit. That sucker should really fly on an M1939!

You probobly already know this, but go low and slow for the cert flight. I have witnessed a plenty learn that the hard way.

Why is everyone so dead set on low and slow for cert flights? All that tells me is that I want to be quite far away when Mr. LOC Magnum J350 L2 cert is allowed to fly his brand new K1275R he just purchased. ( I use L2 as an example since I feel that is where a lot of troubling things can happen really fast.) I applaud his desire to fly on an M1939. Obviously he has the skills to build his birds strong enough to take the thrust. Apparently those people who learnt the hard way were not experienced and skilled enough to attempt an L3 flight.

A guy I fly with only flies MD and near MD. For his L3 he went with a 4" bird on an M1315. Punched about 16-17K feet and recovered beautifully. Certfication achieved. Another guy I also fly with 7.5" bird another M1315 yet no certification. It only went about 6800 feet. Was really low and slow yet he failed when his deployment did not function properly since his charges were undersized. Lack of experience with that size airframe and parachutes.

Anyways, looks good Brent! I look forward to hearing about your successful L3 flght!

MadMax,
I appreciate your point of view. My last four builds have all been minimum dia. I am an altitude/velocity junky. The rocket actually simms at 12,000 ft and 800 Mph. Taht is a prelim. I am sure as the rocket gets built and I input exact weights etc., it will come down to something more like 7,000 ft. and below Mach. I don't consider that low and slow. If it survives the L3 flight, then the next day it is getting flown on either a full M or a N, plus 6 full sized 38mm's all lit off the pad. Maybe that's a little more to your liking? Hey my TRA joining package just arrived!

Well I will have some more photos after this weekend. I am beveling the fins as we speak, jsut glassed my son's 4" tube, and will be doing all the centering rings and bulk heads tomorrow.

should have some great photos Monday night.

Brent

I got the fins beveled today. No elecrical sanders were used in the beveling of these fins.. They were done entireley by hand. I used a wood rasp to make the bevels and sandpaper on a wood block to touch them up. My arms feel like spaghetti,,

Originally posted by MaDMaX
Why is everyone so dead set on low and slow for cert flights? All that tells me is that I want to be quite far away when Mr. LOC Magnum J350 L2 cert is allowed to fly his brand new K1275R he just purchased. ( I use L2 as an example since I feel that is where a lot of troubling things can happen really fast.) I applaud his desire to fly on an M1939. Obviously he has the skills to build his birds strong enough to take the thrust. Apparently those people who learnt the hard way were not experienced and skilled enough to attempt an L3 flight.

Click to expand...

I'm a fan of low and slow personally, which is why my cert flight was low and slow. 6200' on an M1419. I don't get near the enjoyment out of a speed/altitude rocket as I do something that is dramatic and can be witnessed throughout the entire flight. That to me is far more exciting than a quick shot off the pad followed by squinting your eyes hoping for a glimpse of the rocket followed by three hours searching for it.

As for you, Brent, I can't wait to check this bad boy out! Looks awesome so far!

Made progress on our LDRS project today. I'll start a thread on that one soon.

awesome, can't wait to see some pics..
Is this the Bull Dog?

Nope. We had to suspend that project for a bit due to some un-forseen events with several of our team. But I promise you will like what we're cooking up!

I like low and slow to!!!

Chris what was your thrust to weight ratio on your level 3 Thor?

Lee

It came in at 7:1.

For those of you who have been having a hard time wrapping your head around how this is going to look, here is the Rocksim file. I couldn't get RS to do the fins how I wanted them, but close enough.

Originally posted by mach66
For those of you who have been having a hard time wrapping your head around how this is going to look, here is the Rocksim file. I couldn't get RS to do the fins how I wanted them, but close enough.

Click to expand...

Kinda as I imagined... Looks good!

ATTENTION APOGEE!

We need to get the apogee guy in this thread so he can see that some of our ideas are limited to some rocksim abilities. I LOVE Rocksim but on the fins, your limited to certain designs. Wouldn't it be nice to have as many plot points or direction changes as you wanted for your custom fins? It could be a downloadable update for the current Rocksim.

Ian,

As far as I know you can add hundreds of points in a custom fin design--I've done it before when you add a radius for instance.

-Tim

Originally posted by chicagonative17
ATTENTION APOGEE!

We need to get the apogee guy in this thread so he can see that some of our ideas are limited to some rocksim abilities. I LOVE Rocksim but on the fins, your limited to certain designs. Wouldn't it be nice to have as many plot points or direction changes as you wanted for your custom fins? It could be a downloadable update for the current Rocksim.

Click to expand...

Maybe I need to check the updates because mine can't. Now I am curious how he couldn't design his fins the way they are supposed to be designed.

all I know is I had a hard time figuring this out. When using custom, you can't do forward swept, when doing eliptical/whatever it is, the one I used, you can't add points..

It is my feeling that Rocksim is limited in many ways, however he feels this is beneficial to the average user.

Oh well, I have had Rocksim for over a year now, I have built 5 rockets over that year and this is the first time I have ever used Rocksim.

Usually, I get a design in my head and it works perfectly. This design was in my head, so it was nice to see Rocksim agree with it, even if it is a teenie tiny bit over stable ( wich I prefer).

Brent

Brent,

I don't quite understand. In less than a minute I built a forward swept fin design as attached. It seems very easy and I find Rocksim will do most anything you can dream of. Maybe you need to spend some more time with the program.

-Tim

Originally posted by mach66
all I know is I had a hard time figuring this out. When using custom, you can't do forward swept, when doing eliptical/whatever it is, the one I used, you can't add points..

It is my feeling that Rocksim is limited in many ways, however he feels this is beneficial to the average user.

Oh well, I have had Rocksim for over a year now, I have built 5 rockets over that year and this is the first time I have ever used Rocksim.

Usually, I get a design in my head and it works perfectly. This design was in my head, so it was nice to see Rocksim agree with it, even if it is a teenie tiny bit over stable ( wich I prefer).

Brent

Click to expand...

1. Select "fins".
2. Go to "A free form fin set".
3. Go to the "Plan Points" tab and you can put as many plots as you want.

I just tried it. Selected a free form fin set. By entering in a negative x-axis value for the non root edge of a fin, rock sim will display the fin correctly. I don't know if the negative number messes up the calculated characteristics of the rocket (Cp, Cg, Cd, etc) or if the negative number confuses the flight simulations.

Anyone have a definitive answer?

Well yeah, that is easy, but they don't look like my fins

The fins on my RS file are the fins, just without the pointy tips.
I printed out the template and added the tips.

Plus, as stated above, this is the very first time I have used RS.
So getting more aquainted with it is on my list of things to do. I should find the time to do it in about a year

Brent

No problem, here are your fins (or a facsimile thereof)...

Originally posted by mach66
Well yeah, that is easy, but they don't look like my fins

The fins on my RS file are the fins, just without the pointy tips.
I printed out the template and added the tips.

Plus, as stated above, this is the very first time I have used RS.
So getting more aquainted with it is on my list of things to do. I should find the time to do it in about a year

Brent

Click to expand...

Well, my CR & BH operation got cancelled, so instead I started glassing my fins. I am giving them one layer of 6oz FG prior to installation and tip to tip. With fins this big, I want them plenty stiff.
I used a foam sleeping matt and a huge sheet of .005 mylar. Here is the setup.


Here is the setup with both sides of a fin glassed.


and here is the setup closed (tacoed) with 4 60 lb. sand bags on top. Hopefully the weight is enough to get a good wrap on my bevels.

In case anyone was wondering why I went with the name "The Predator" first it's a perfect name for a missle, second because I have been waiting for the perfect rocket to stick this on.

Lookin' good Brent! Did you find a person to make the decal for you on TQC forum?

Ian,
I found some one to do the graphics, in fact I have it, just need to upload it to photobucket and replace this one. Now I need to find someone to do the actual decal.

There now replaced with the actual graphic I will use.

Brent

From your Rocksim drawing of the Predator cluster config:

I have built three cluster rockets now, and flown them a total of nine times (between the three). Also, I spent the winter "coaching" a TARC team and we did 25 flights of the same rocket with the same motor.

After this weekend at MDRA, and my TARC experience, I would avoid clusters unless you can't get the power you need without them.

Inconsistency from motor to motor in terms of burn time, ignition speed, total impulse and flight characteristics makes me prefer one large 98mm over 2, 3, or 4 smaller motors.

Just one opinion. I'm sure 5 people will disagree with me.