LOC EZI-65 Supersonic Project

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DMehalko

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Hello!

Now with my L2 Warlock project complete and cert achieved its time to move on to the next project! I want to start learning/playing with dual deploy, tracking, higher altitudes and higher speeds. Then I decided why not try and break the sound barrier at the same time? So why not do that all in one build? Well the EZI65 will be that build!


To do this all be seeking some expertise from you all! Off the top of my head the additions to the build will consist of;
  • Carbon fiber wrapped airframe (aesthetics as a secondary purpose :D )
  • Carbon fiber or fiberglass laminated fins
  • LOC precision electronics bay
  • Redundant Missileworks flight computers (RRC3 and RRC2)
  • Tracking?
    • Unsure, need to do some research
    • Likely need to be in the nose for weight and reception due to the carbon
  • 54/1706 case with a K550 in it should push this bird to around 830mph and ~6200ft
    • Will a thrust plate be needed?

Attached is a quick Microsoft paint mock up of the paint scheme, the 'black' will be the raw clear coated carbon fiber:cool:

Build commenced! Should be fun :)
 

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Tracking with a Featherweight is damn hard to beat for simplicity. Throw an av-bay into the nose cone for it, and buy a LabRat sled to protect it. Mine have been on tons of flights and they work great.

Good luck and enjoy!
 
Hello!
To do this all be seeking some expertise from you all! Off the top of my head the additions to the build will consist of;
  • Carbon fiber wrapped airframe (aesthetics as a secondary purpose :D )
  • Carbon fiber or fiberglass laminated fins
  • LOC precision electronics bay
  • Redundant Missileworks flight computers (RRC3 and RRC2)
  • Tracking?
    • Unsure, need to do some research
    • Likely need to be in the nose for weight and reception due to the carbon
  • 54/1706 case with a K550 in it should push this bird to around 830mph and ~6200ft
    • Will a thrust plate be needed?

Attached is a quick Microsoft paint mock up of the paint scheme, the 'black' will be the raw clear coated carbon fiber:cool:

Build commenced! Should be fun :)
Tracking: even a simple RDF unit will work. I use LL Electronics Falconry trackers and a Walston receiver.
I recommend a K1103 for the motor. 300 free extra N-s, higher thrust for higher speed and the same price :)
A couple layers carbon tip to tip will suffice for the fins and a wrap on the body tube will also be enough. The 1/8" thick, symmetrical fins are prone to flutter. This rocket was designed for the long burn motors available at the time, hence the name, EZ-I65. J90s are close but a J125 was too much for a stock original EZ-I65 :)
 
Tracking with a Featherweight is damn hard to beat for simplicity. Throw an av-bay into the nose cone for it, and buy a LabRat sled to protect it. Mine have been on tons of flights and they work great.

Good luck and enjoy!

Who makes the featherweight?

Tracking: even a simple RDF unit will work. I use LL Electronics Falconry trackers and a Walston receiver.
I recommend a K1103 for the motor. 300 free extra N-s, higher thrust for higher speed and the same price :)
A couple layers carbon tip to tip will suffice for the fins and a wrap on the body tube will also be enough. The 1/8" thick, symmetrical fins are prone to flutter. This rocket was designed for the long burn motors available at the time, hence the name, EZ-I65. J90s are close but a J125 was too much for a stock original EZ-I65 :)

Man that motor makes a ton of thrust, the K550 sims to about 830mph already hahaha. But definitely going to look into that one!

You might like this video:

I saw your video a ways back! For some reason always been drawn to the simplistic yet attractive nature of the ezi65, pumped for this build!
 
Featherweight is the brand.. quick google and you’ll find them. Adrian, the guy who owns/runs it, is a great guy. If/when you order, make sure to grab one of the battery/lipo chargers to get you started. Lab Rat Rocketry is in DFW and he makes some really slick stuff, the shock cord sled/protective sleeve is nice.

https://www.featherweightaltimeters.com/
 
  • Carbon fiber wrapped airframe (aesthetics as a secondary purpose :D )
  • Carbon fiber or fiberglass laminated fins
  • LOC precision electronics bay
  • Redundant Missileworks flight computers (RRC3 and RRC2)
Sounds a great challenge and I'm looking forward to following your build! Just be aware that cf laminating the Loc tubing + the fins, and adding the Loc Av bay will add to the built weight considerably. I have a scratch built 4" w/ 54 mm mmt (see avatar picture) not that dissimilar to the EZI-65 (albeit 4 fins not 3, and laminated with fg). It only just touches Mach 1 on a CTI K740. Granted, it's built like a tank, but if you're going to go with that 4"/54mm combo and aiming for M1.5, my advice would be to research and find ways to build as light as possible.
 
kinda crazy but i have had a similar project in my head for quite some time. i was originally going to sleeve mine whit couplers and forgo the glass / carbon, but the latest version sitting in Open Rocket has a carbon booster. ...and G10 fins.

second the K1103X suggestion.

looking forward to following along!
 
...
I want to start learning/playing with dual deploy, tracking, higher altitudes and higher speeds. Then I decided why not try and break the sound barrier at the same time? So why not do that all in one build? Well the EZI65 will be that build!
...

I did much the same, but on 3" LOC/Madcow frame although after playing with a bunch of fin designs in FinSim, I am planning to go with the clipped delta.
https://www.rocketryforum.com/threads/hpr-custom-build.162115/
 
Thanks for the input guys! Ya that k1103x looks like it would be a ton of juice for this thing! Once I get all the final weights I’ll go sim crazy haha.

I will say soller composites makes a great product! sleeves are just so nice and easy to work with! I bought their shrink wrap as well, but kid you not my shop heat gun that has been trusty for ever failed half way through the shrinking...

So ended up just pulling it off and getting it as smooth as possible which may have been a good thing as I was able to pull a bit more excess resin from the fibers.

Another small mod was to extend the payload bay by a few inches to gain more main chute room. just a mild stretch
 

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Don't forget to strengthen the coupler too. My first shot at going mach (AT K550) ate my glassed cardboard rocket. I just used a stock cardboard coupler.

Tony
 
I beg to differ. A stock EZI will rekit itself long before it reaches mach. I have seen it several times. the fins will flutter themselves right off.

I just looked up the fin thickness I retract my previous statement
 
So ended up just pulling it off and getting it as smooth as possible which may have been a good thing as I was able to pull a bit more excess resin from the fibers.

How did you avoid all the pin holes? That was something I struggled with when I used the soller sleeves.
 
I beg to differ. A stock EZI will rekit itself long before it reaches mach. I have seen it several times. the fins will flutter themselves right off.

I have personally seen a stock LOC EZI fly on a long burn 75mm L CTI motor (Tripoli Mid-Ohio)...twice with no problems. I have also seen enough stock wood and paper rickets (LOC) made with wood glue, handle high thrust, high altitude-mach conditions, to know that most people tend to overbuild. Either way....whatever one's comfort zone is. If the fins are flat and the rocket is made well. It will have no issues. I have seen it.
 
long burn is kifferent from instant mach. I stand by my statement. Ron Schultz once said J100, sure, J125, not so much. Sure enough, fins came off on a J125

I hear ya' and know what you are saying. I tend to agree.

However, long burn also means it is (the rocket) getting lighter and going much faster over time. I have also seen many rockets made of wood and paper easily handle mach launches. Including my successful L3 project (fiberglass free) that went mach 1.24 It has plain wood fins and standard LOC airframe lined with couplers.

Wood and paper rockets are a heck of a lot tougher than the current school of thought and tougher than people think when built properly. Properly bonded wood glue is stronger than the wood itself. But carbon fiber is a sure thing for strength and sure is strong. It will also keep it dry should it get wet. I LOVE the way it looks when done. I hope he does not paint over it.

It's all good....just have fun.
 
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How did you avoid all the pin holes? That was something I struggled with when I used the soller sleeves.

I just kept squeegeeing excess resin out until i was happy, came out great especially for never sleeving anything before

I hear ya' and know what you are saying. I tend to agree.

However, long burn also means it is (the rocket) getting lighter and going much faster over time. I have also seen many rockets made of wood and paper easily handle mach launches. Including my successful L3 project (fiberglass free) that went mach 1.24 It has plain wood fins and standard LOC airframe lined with couplers.

Wood and paper rockets are a heck of a lot tougher than the current school of thought and tougher than people think when built properly. Properly bonded wood glue is stronger than the wood itself. But carbon fiber is a sure thing for strength and sure is strong. It will also keep it dry should it get wet. I LOVE the way it looks when done. I hope he does not paint over it.

It's all good....just have fun.

Nice! Ya this one will be overbuilt slightly without trying to go crazy, and yes in my planned paint job the 'black' section will be the raw clear coated carbon, not paint :)
 

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How much motor can an EZI-65 handle? I routinely flew mine on J275's and J350's, no problem. I built her strong two ways. 1.) epoxied in tube couplers the full length of the body tubes. 2.) filled the annular space between the booster body tube and the motor mount tube with PML's expanding urethane foam (publicmissiles.com/product/adhesives). If you're determined to go supersonic, apply fiberglass or carbon fiber to the fins tip-to-tip.
 
I'm surprised no one has mentioned this: if the speed and altitude together pose a challenge, you might add a boat tail. I added a PML 4 inch to 75 mm boat tail to mine, which contains the 54 mm motor mount up inside. I'll let you know how it goes when I fly the thing one of these years.
 
Good feedback guys, ya might look into a tail section on it, but want to retain the classic ezi65 look as best as possible, stretching it a few inches was already, ....well a stretch haha.

got my paint mask in from stickershock! I’ve always loved the snap ITC font and wanted to use it
 

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Been a busy few weeks with the holidays and work activates, so not much progress but now refocusing here.

Next up I'm going to be building the fin can/mmt assembly outside of the airframe and looking for some input to survive mach. Right now, I'm planning on using 6ounce cloth to do tip to tip across the motor mount tube, then once the fin can is installed in the airframe doing a second, 4 ounce layer tip to tip on top of the carbon. Is this sufficient? Overkill? My other thoughts were to stick with 2 layers of 4 ounce cloth.

Finally, anything dictate when a thrust plate would be needed?

For picture updates, i got my custom color matching chute from top flight! Kit came with a 36", but since this one will be a little heavier, and will be flying dual deploy i upped to a 58" chute.
 

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Right now, I'm planning on using 6ounce cloth to do tip to tip across the motor mount tube, then once the fin can is installed in the airframe doing a second, 4 ounce layer tip to tip on top of the carbon. Is this sufficient? Overkill? My other thoughts were to stick with 2 layers of 4 ounce cloth.
Probably, but that's what we do!

Finally, anything dictate when a thrust plate would be needed?
The force of the motor will be transmitted from the aft end of the motor tube to the airframe through all the interlocking structure of fins and CRs. I always put an CR at/near the aft end of the rocket, but I'm not sure you really need anything more elaborate than that.
 
(Talking out my backside.) The concerns named above by people talking through their correct orifices were all about fin flutter. So the purpose of the lamination is primarily to improve the stiffness, and perhaps to withstand some flutter. It seems to me that a fin to fin layer on the outside of the airframe does that, and doing the same on the motor mount probably doesn't add much. 4 ounce, 6 ounce or 2 ounce, FG or CF I would not presume even to suppose.
 
Hello All! Back at this one, was sitting on the side while i messed with other silly projects.

So fins had some warp i could not get out, and if i want to go fast, i know thats just not going to cut it. So friend in the club was awesome and cut me some new fins out of G10, these are 1/8" thick, a little heavy, but now not going to worry about doing tip to tip glass. I will do some 6oz over the motor tube to the first small bits of the fins
 

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