Next Project "NO LIMITS"

[Theory]

When designing rockets, or thinking about what I want to build next, I am often driven by the motors that I want to fly or the performance I am looking to achieve.

My next project is a supersonic spear aimed directly at all out performance. Built for full tilt 76mm K motors and the largest 54mm motors on the market (yes to include the Loki 54/4000) I call her NO LIMITS!

At a high level she will be 4" in diameter, 92.5" long, sporting a 76mm motor mount, a conical nose cone from MadCow, and an Aeropack tail cone.

The majority of the parts will be from a WildMan Extreme kit so that makes things very simple. Contemplating a set of custom double beveled fins from PLM, but that will be a game time decision. All structural bonding will use System Three T88, and RocketPoxy will be used for the fillets and where I need an adhesive that will "stay put."

Plan to use the "epoxy dam" method of fin attachment. Believe that this will be perfect as there will be about .5" between the motor mount tube and the inside of the air frame. The "dams" will be made with 1/2" bass wood sticks.

Recovery will be fairly standard, 1/2" tubular Kevlar bridal, OBH harnesses and, if she is light enough, I will use the 8' RM chute that I have laying around. To keep cost down I will be using the same electronics sled and altimeters (RRC2+ and RRC3) that I use in my WM Drago 4. They are flight proven and, well, I have them.

Will be building a provision in the nose cone to house a GPS tracker. Really liking the Missile Works RTx system. Jury is still out there...

Ordered the parts yesterday along with a J800T, K1100T, and K1103X for shake down flights. The CTI 2 grain cases and AT 2560 hardware are proving to be challenging to find. Really want to let her rip on a K1000, but that wont be till fall.

Looking forward to this one!!!

 

[HyperSonic]

Looking forward to this one!!!View attachment 455950

So am I. Will be following with interest!!

 

[Theory]

thanks HyperSonic!

"No LIMITS" isnt in the same league as Pepe, but then us East coast flyers play a slightly different game

The larger of the two fields I routinely fly at (Battle Park in Culpeper VA) has a standing 14,000' waiver, but we know that, in reality, the field "maxes out" at about 9,000 -10,000 feet.

Based on many Open Rocket SIMs, so long as the wind at altitiude is ok, I should be able to get her to go on a solid L and not be at risk of overflying the field.

 

[T34zac]

Looks a little shorter and a little lighter than my Frenzy XL. Easily stays under 10k on baby Ls and goes to just over 12k with full Ls. Should be good for staying under your waivers until you stuff an M inside.

Looking forward to seeing more of this.

 

[Theory]

An open rocket design is one thing, but a pile of parts is something else!

waiting on a quote for the fins from PML. Hope to start laying out the motor mount this weekend. At the very least I should be able to get the airframe sections cut to the length I want them too be



slight change of plans as I am now thinking of building a dedicated electronics sled with two RRC3s for this one. Sharing components between rockets does save some money but brings its own complexities

 

[Theory]

Moving forward

The tubes are all cut and everything has been very thoroughly washed. Got her laid out and started marking locations for sheer pins and mounting screws.

Next up is the tail cone, and marking locations for the three centering rings and the pair of rail button “backers”

 

[Theory]

Spent some time sanding the centering rings and dry-fitting the tail cone assembly.

Given how the tail cone recessed into the airframe, there isn’t much room for error.


Initial spacing was done with a 54mm motor and the aero pack adapter system. Will wait to adhere everything until my 75mm case shows up later this week.

Can’t get this wrong and there is no replacement for a real world dry fit with the hardware you will fly.

Patience and more patience...

 

[rfjustin]

I like this project.... and the nose cone. Do your fins need beveled?

 

[Theory]

like everything about that one there rfjustin!

getting the fins from PML with both the leading and trailing edges beveled. I've never dealt with PML before, nor do I know what their custom fins are like. I do anticipate that I will need to clean up the bevels a little, but nothing I can't handle. if all goes well from USPS they will be here by the end of the week.

 

[rfjustin]

like everything about that one there rfjustin!

getting the fins from PML with both the leading and trailing edges beveled. I've never dealt with PML before, nor do I know what their custom fins are like. I do anticipate that I will need to clean up the bevels a little, but nothing I can't handle. if all goes well from USPS they will be here by the end of the week.

PML does great work, I'm confident you will be pleased.

 

[Theory]

PML does great work, I'm confident you will be pleased.

that’s great to hear

 

[Theory]

Made some progress tonight

all areas to be bonded were lightly sanded with 220grit then wiped with denatured alcohol. Then it was time to grab the epoxy and get to work.

Love System Three T88. Not looking to start an epoxy debate, more just sayin



At this point? only needed a very thin bead to adhere the centering rings to the mmt





the forward most ring was notched to allow for the Kevlar harness. A 1/4” plywood ring was laminated to the fg ring
to give more forward bonding area. Maybe not needed, but it makes me feel good




complete mmt with the rings tacked in place


Final part for the evening was the forward rail button anchor. Laminated a pair of plywood rings with titebond II, then cut the ring into thirds. A “on third section” was then epoxied to the forward centering ring with T88. The screw for the rail button will be held by this plywood anchor.

 

[Theory]

Added epoxy to the Kevlar. “She aint goin nowhere!”


next up is the basswood epoxy dams

 

[grouch]

Very clean work there dude.

 

[Theory]

Thanks grouch

 

[Theory]

The fins arrived today.

One word to describe these: magnificent! PML did a great job. Matched my full scale template 110%!



leading and trailing edges



test fit in the slot. Was a little tight, but happy to sand off 1/64. Much better than being lose


need to get working on the epoxy dams. Was tied up with other stuff over the past week+.

now that the fins are here it’s GAME ON!

 

[HyperSonic]

Spent some time sanding the centering rings and dry-fitting the tail cone assembly.

Given how the tail cone recessed into the airframe, there isn’t much room for error.
View attachment 458485View attachment 458486View attachment 458487

Initial spacing was done with a 54mm motor and the aero pack adapter system. Will wait to adhere everything until my 75mm case shows up later this week.

Can’t get this wrong and there is no replacement for a real world dry fit with the hardware you will fly.

Patience and more patience...

When I installed mine, I was off by about .010. Good thing I was long on my measurement, so I ended up cutting a shim .010 thick so it would fit between the motor and the bottom of the boat tail. Now when the boat tail meets the bottom of the airframe, It also touches the bottom of motor. Must be very accurate with your measurement like you said.

 

[Theory]

@HyperSonic

yes! Honestly not the biggest fan of this tail cone set up and the way it works with the 54mm adapter.

will make it work...

 

[Theory]

Working the epoxy dams. Cut the basswood stock to length and began beveling to match the mmt

these will be tacked in place with System Three 30 min then filleted with T88 on the outside edges

 

[Theory]

The first set of epoxy dams is in place.
As with all fiberglass bonds, I sanded with 220 grit the wiped everything down with denatured alcohol.
Opted to adhere with T88 in place of the 30min I originally intended to use.

 

[Theory]

Epoxy is set and the fit / spacing confirmed.

100% what I was looking for as I did not want a ton of epoxy pooled around the fin

 

[Theory]

Second set in place



Going to fillet each outside edge once all are in place. Not sure if I want to add a layer of glass on top of that. There isn’t a ton of area and as such I’m not sure there will be much added strength

 

[Theory]

The three sets of epoxy dams are in place and the first set of reinforcement fillets has been poured and pulled. Used T88 for the fillets here. With a centering ring on either end it will stay in place. Note, due to its flow characteristics, straight up” T88 is less than ideal for fin fillets



got some air bubbles in the one side. They should work themselves out over the next few hours

 

[Handeman]

So looking forward to seeing this fly at BattlePark this fall!

 

[Theory]

Thanks Handeman!

 

[Theory]

Test fit, test fit, test again

all the epoxy dam channels line up well and with a little sanding the fins slide in slots as they should. Will bond it all together tonight

 

[Theory]

Moving forward. Got the mmt installed. Was able to reach inside the airframe and sand the locations where the middle and forward rings meet the airframe. Sanded with 220 them wiped with an alcohol soaked paper towel.

laid a nice beed of T88 forward and injected T88 to bond the middle ring. Let it cure for over a day before moving on.

Next up, the fins. Sanded the bonding location with 220 and wiped clean as before.



next, mixed up some T88 and poured it into the channel created by the epoxy dams.



next, insert the fin and ensure that all is square



let cure and repeat two more times

 

[tHoagland]

Nice work on the epoxy dams and great Metallica banners in the background!

 

[Tim51]

Superb work. FWIW I've also used drinking straws tacked in with CA to make very light weight epoxy dams. Obviously they don't offer any mechanical strength or fin alignment benefits but they form the epoxy into nice fillets if used with the 'double butter' technique.

 

[Theory]

Thank you all

@tHoagland - two guesses what type of music is playing as I’m building ; - )