It Originally Started As An EZI-65

Originally, I simply wanted to build something since it had been so long since I had built anything with regards to the RC hobby.. Where the rocket idea came from, I am not completely sure but this is what happened..

Having never flown a rocket bigger than a d size and not within the last 10 years, I decided to build something and this is what I came up with.. Originally, it started out as a LOC EZI-65. After reading over the 1 piece of cardboard instructions, I threw them aside and began changing things.. I had no idea what a zipper was with regards to rockets and finally figured it out.. Now, the rocket is a anti-zipper design.. The fins were something out of a horror movie so I decided to change those around.. This was one design aspect of the rocket that took the longest.. Fiberglassing was my worst nightmare and my nightmare came true when I glassed the rear tube.. 3 hours of sanding the rear tube and everything is fine. The front half came out almost perfect after I corrected for my first mistakes

There is still a long way to go as the fins have not been permantely attached and I have yet to finished sanding the forward portion.. I thought I would go ahead and post some pics for a little constructive critism..

Let me know what you think..

Thanks, Sawacs

https://home.attbi.com/~sawacs/rocketproject/Jbweldjob.jpg

https://home.attbi.com/~sawacs/rocketproject/brassmod.jpg

https://home.attbi.com/~sawacs/rocketproject/noseglassed.jpg

https://home.attbi.com/~sawacs/rocketproject/ezi2.jpg

https://home.attbi.com/~sawacs/rocketproject/Qflyer.jpg

Sawacs

Hey,

That looks really cool. I've never done one of those kits before, mabay i just misread something, i dont know but anyways, what are all thos holes for in the second picture? Are you gonna certify and fly it as intended (I65) or just stick with G's and such? Thanks.

-Chris H.

Nice job, Sawacs!
I never have found a kit that didn't have room for improvement.
I'll bet you're an RC guy.

Awesome job with that EZI, sawacs. I love the modifications to the fins, and the anti-zipper design is a great idea and works very, VERY well. If you're planning on flying larger or higher-thrust motors, might I suggest a tip-to-tip lamination in fiberglass on the fins? EZIs are designed for lower-thrust motors like the I65 and J90 (which are AWESOME to watch) but if you ever plan on putting in a motor like a J570W, 6 grain Pro38, K550W, or anything like that, you'll need this to keep the fins from fluttering off. Then again, I tend to WAAAY overbuild (cause I like Kosdon motors ), so take my advice with a grain of salt


HTH.

Thanks for the feedback fellas... Rocketfreak, the holes in the coupler are for the anti-zipper design. Normally, the shock cord is attached way down in the rocket tube ( front centering ring of the engine mount) which can cause a long gash to get ripped into the side of a rocket since the shock cord places a lot of tension on the upper section of the rocket.. Picture opening a bag of feed on the farm, you pull backwards on one of the strings and it rips the bag open creating a long gash: same effect for the rocket.. Unfortunately, I will not be able to fly this rocket first since the motors are too powerful and I am not certified for those engines.. hence the smaller rocket in the background that I will use as a level 1 cert.. Btw, I decided to place brass tube inserts in the ejection charge holes mainly for looks and also because I had the tubing available..
Ibebip, roger the rc guy..

daveyfire, the rocket is being built like a brick shouse if ya know what I mean.. The fins have been glassed and will have a piece of glass layed on each side of the fins and then a fillet poured in.. The same thing will be done inside the tube. Also, where the fins meet the motor mount, I am planning on placing either balsa sticks or spruce sticks on both sides of the fin and glassing that entire area. Jbweld has even been applied to the washer and bolt areas along with the small groove in the eyelet as a little added piece of mind

The only thing holding me back from making real progress if permantely mounting the fins.. I have yet to find a method I am confortable with that makes sure the fins are aligned properly..

Thanks, Sawacs

wow you really built the EZI tough. I love mine. I fly it all the time.
btw the fins look alot like magnum fins...it is like a mini magnum

The way it sounds like you're building it, it could take a K1100T! Good job Sawacs. That rocket will last you a long time .

Thanks fellas.... Awite, give me some pointers.. I have been staring at this rocket for the last two days and have done nothing.. why, because I am terrified if the fin alignment process... I'll take some pointers.. Is there a surefire method for making sure they are absolutely centered?

Thanks. sawacs

I built a fin jig similar to this one by Jim Ball. I've seen other fin alignment jigs too. Unfortunately, I think the only way you are going to guaranteed a perfect alignment is to make a jig.

Jim Ball's Fin Alignment Jig

Fin alignment jigs do make the process much easier. However when the rocket has through the wall to the motor mount fins they are very easy to align correctly just useing your best judgment. This is how I build my EZI and it came out great. The rocket flys perfectly straight everytime. There is a video of one of the flights on Dougs website
here is the link

https://www.gardei.com/Oct202001

go here and then scroll half way down the page. The file is called
Ryans G40 EZI.mpg
sorry I couldnt get the direct link to work

Try this Ryan

https://www.gardei.com/Oct202001/Ryans_G40_EZI.mpg

Thanks Doug. I probably wrote the last part wrong.

SAWACS
Check "Radial Location" of the fin slots by measuring (chord) distance between each.
If memory still serves me correctly, the EZ-I65 is a four-finned rocket and I'm willing to bet dollars to donut holes that the distance between those slots is not going to be equal.
But as long as each fin plane is perpendicular and parallel to the longitudinal axis of the rocket, your rocket will fly straight and true if basic stability exists, because the fins are quite actually control surfaces.
And being an RC Guy, you certainly do know what that means.

In this message, I have tried to attach a drawing to show what I mean. We'll see if it goes through.

...Thats not rare...on my Ezi-65 one of the fin slots was 1/8" off radialy....I also used a Jim Ball sytyle jig, but I had to skew each fin slightly to get things somewhat equal...It didn't effect the rockets flight enough for me to tell.....I E-mailed Barry at Loc and he sent back an E-mail saying that one of the operators must have been having a bad day...I wasn't too impressed with that responce....being fairly new to high power at the time

that was also my level one rocket...

Evening gents...

After walking past the rocket for a week dreading the inevitable, I finally said the heck with it and began glueing fins in place I used a simple cardboard box weighted down with vast calibers of bullets used in reloading.. I cut out two sides of the box to allow the rocket to nestle between and then weighted the rocket down.. This method worked out very well. After the fins were tack glued with CA, I twisted the rocket, measuring all of the fins tip distance from the work surface and every fin tip was right on the money.. I do not think I could have done any better with a jig to be honest

Thanks to everyone for the suggestions..

Btw, the EZI-65 is a 3 fin design.

Sawacs

It certainly isn't rare, Stymye. And thanks for confirming the fact.

For those of you without instruments for accurate measurement of chordal distance, here's a way to find out the amount of deviation:

Cut a strip of paper that is long enough to wrap around the rocket's airframe where the fins will be mounted. Tape it in-line with one of the fin slots on that part of the airframe. Wrap it around the tube and mark it where it touches the end that was taped in-line with one of the slots.
Then unwrap it and remove the taped end from the airframe. With a scale (That'd be a ruler having increments finer than 1/16 inches or 1 millimeter), measure the distance between the strip's taped end and the mark you made. This measurement will be the circumference of the rocket's airframe diameter. (The absolute distance around its outside, or one revolution of rotation of a known radial point on that surface.)
For equal spacing of 3 fins, divide the total length by 3.
For equal spacing of 4 fins, divide the total length by 4.
But with any number of fins, the first point of radial location is always at the taped end of the paper strip -like starting at zero and moving along a line of numbers on a straight edge.

The same principal of measurement may be applied when making marks for location of masking tape prior to painting the rocket.

Another update.. Here is the fin alignment method I used... Simple cardboard box top with cutouts and a bunch of weights..
Worked great!

Also, I grabbed some motor mount adapters for the two rockets..( building a level 1 side by side with this one. I know I will not be able to fly the EZI-65 rocket on a 54mm so I had to grab the mmt adapter to downsize to a 38..

When I began building the adapter, I really did not like how flimsy they were.. I just dont't understand why the kit itself has to cut corners and offer such a shot motor mount tube.. Even the stock EZI-65 motor mount is really short when you look at some of the egines out there and their length.. My philosophy is why support half a motor when you can support the entire motor I decided to re-inforce the motor mount using spruce strips which are CA glued in place.. Epoxy wasnt necessary for the portion. I will have to grab one more motor adapter in order to encase the entire length of the 38mm tubing with a structure like the one in the photo but I think it will be worth it.. The smaller adapter on the right is the the level one rocket which needs to be downsized from 38 to 29 for the initial flights..

Any comments are most welcome as I am not sure I know what I am doing but it feels right

Fin jig per say
https://home.attbi.com/~sawacs/rocketproject/finalignment.jpg

Motor mount adapters
https://home.attbi.com/~sawacs/rocketproject/mmtadpter.jpg

Sawacs

Awesome looking rocket sawacs

Finally installed the fin reinforcements.. I placed 1/4" thick balsa sticks laminated with 2 hour epoxy and glued them to both sides of the fins.. The only thing remaining is making the fillets around the reinforcements, glueing the railbutton support in, and coating the rest of the inside with epoxy and capping the end.. I should have that finished tomorrow at which time I can make the outside fin fillets, sand and start applying primer Boy, never thought I would make it to the primer stage with this thing..


Fin Reinforcements

Sawacs