An Agglomeration of Andromedas (HPR)

[les]

Prepped the areas for mounting the pods and antenna. The tape limited where the sanding occurred



Made a jig to align the pod - tacked the pod on with CA


The kit does not include the dowels for the antenna array. I used some 3/16" dowel cut to 7.5" long based on the Semroc (LPR) kit. I sanded the ends down to points. I tacked these on with CA. I had marked the mid-point of both the dowels and fin for alignment. I do not intend to epoxy these as I want them to be sacrificial if need be. Note that I used the plastic bag to keep the CA from gluing to my board. And since the 3/16" dowel is slightly bigger than the fin thickness, I used the ruler as a spacer to lift it up a bit. Then using an angle to ensure the antenna was 90 deg, tacked it in place with CA.

 

[Wally Ferrer]

The kit does not include the dowels for the antenna array.

Mine came with a pair of short rods for that... seems odd yours didn't. Looking good, nice progress!

 

[les]

Mine came with a pair of short rods for that... seems odd yours didn't. Looking good, nice progress!

Question - what about the other "detail" pieces, such as the rectangles and circular disks for the sail, and the pod details??? Pix from MPR andLPR builds. I got some rectangles for the sail, but not the circular disks nor detail pieces for the pods....

 

[Wally Ferrer]

Question - what about the other "detail" pieces, such as the rectangles and circular disks for the sail, and the pod details??? Pix from MPR andLPR builds. I got some rectangles for the sail, but not the circular disks nor detail pieces for the pods....

View attachment 430063 View attachment 430064

Same- I got the rectangles for the sails, but none of the disks or pod details.

 

[Tim51]

I got some rectangles for the sail, but not the circular disks nor detail pieces for the pods....

Could you shape them out of 40 thou modeller's plastic sheet (what's known over here as 'plasticard') and attach with epoxy..?

 

[les]

The rectangular pieces for the sail looked off compared to my LPR and MPR builds. Using the LPR as the "scale basis", the rectangular bits are off. Significantly. Now of course, based on my discussions for the tube length, transition, and nose cone we know this is a semi-scale (loosely) upscale. However, I did some digging and found some polystyrene. I found a perfect piece to make 4 pieces. But as a note, the thickness is off (too thin). Here is how the rectangles should be vs the supplied ones.



I was thinking of buying some fender washers for the disks, but then had a thought. An 18mm engine block is almost the right size. My thought is to fill the center with an epoxy/micro-balloon slurry and glue these on. These pieces are just sitting on the sail, but it gives you an idea of my thoughts. Comments?
Actually - new thought - just cut a card stock cover for the block.....

 

[les]

I also sanded down my wooden dowels to align with the fairings. Before and after....

 

[Wally Ferrer]

I like the idea of the engine blocks. I'm going to dig through my scraps bin, I usually save the bits from centering rings and other excess, I may have some discs that will work. If not I have engine blocks and cardstock. I haven't measured, but I don't think my rectangles are as off as yours, but don't know how close to 'scale' they actually are.

 

[les]

I haven't measured, but I don't think my rectangles are as off as yours, but don't know how close to 'scale' they actually are.

Based on 3X of the Semroc version, they should be about 1.5" x 3"

Also, if you have any spent 18mm engine casings you could slice one up......

 

[Wally Ferrer]

Those strips you have almost look like the pod details, but probably too wide.

 

[Wally Ferrer]

Based on 3X of the Semroc version, they should be about 1.5" x 3"

Also, if you have any spent 18mm engine casings you could slice one up......

Yes, mine are 1.5" x 3"... With your antennas missing, and the size discrepancy of your rectangles looking potentially like the pod strips makes me wonder if the missing details are intentionally left out or simply got left out when packed... Only Tim knows for sure...

 

[WILDMANRS]

that was us the new antenna will go out today or tomorrow.
we ran out of the carbon rods.
the squares i had some pieces of g10 that looked close so i through them in and did 't bother to measure to scale .

 

[Wally Ferrer]

that was us the new antenna will go out today or tomorrow.
we ran out of the carbon rods

Any chance you can speak to the rectangle size differences, and no disks or pod strips? We can obviously make them, just wondering if they were overlooked and accidentaly left out or if it was a design decision...

 

[les]

I grabbed some .25" x .125" rectangular polystyrene. The LPR version had the pod strips as .1" wide, so a tad small (.25 vs .3) but close enough. Cut to length. Marked the tubes, scuffed (that pix failed) and glued on one pod using plastic cement. The pieces start .375" from front edge and are 2.4" long. They are spaced .2" apart

 

[les]

This is the stuff I used for the pod detail


Working the disks


And through JimZ site, I got a template for the sail detail. I blew it up 3X. It does appear the 1.5" x 3" is a bit short, but good enough. Also the ring placement doesn't align. I used the rings to cut my own slots. Showing how this sits on the sail.


One detail - notice the curve/rings don't quite align. That got me to investigating. The sail fin has a root length of 9.25". To be a true 3X upscale, it should be 10.875". But we already knew with the nose cone, transition, and tube length that this is more a semi-scale upscale......

 

[les]

Used plastic cement for the polystyrene panel and CA for the disks to attach to the sail. I scuffed the surfaces before applying - meant to get a shot but I was getting short on time and forgot.


What are the remaining tasks?
Miles of tape masking and fillets (or just looks like it will be miles)
Drill & tap holes for coupler/Avbay
Build Avbay
Install rail buttons
Complete Rocksim update - see if weight will be required in nose. I started with a Rocksim file from Rocket Reviews, used the 3X scaling feature, then been correcting to match this version.
Glue coupler to nosecone
Recovery retention for lower body (I have some weird ideas for this)
Prime & paint - will need to reconfigure my shop like I did for my L3 rocket as it won't fit my normal spray area

 

[Wally Ferrer]

Thanks for sharing, I'll be able to do a better job assembling mine than I otherwise would have...

 

[les]

Started masking for fillets....


Attached is a second draft of a Rocksim file (why it is called Wildmana - next version would be Wildmanb).
As previously stated, I started with a Rocksim file from Rocket reviews, used the scaling feature for 3X, updated the materials (cardboard/balsa to G10 FG), adjusted some dimensions and got something "close".
I will freely admit I don't measure to the nearest angstrom or picogram, I try to get close and then basically will fix things with a mass object to get to the final measured weight and CG.
When I started, I weighed the entire kit and got about 140oz, When I weighed the individual parts and got about 142oz - close enough. The Rocksim file presently shows almost 146oz. I re-weighed the rocket in its present state and I got 146.4 oz. Once I add the fillets, paint, chutes, etc I'll adjust for the final weight/CG.
And if anyone else wants to play with the file, feel free.....

 

[Nytrunner]

That's pretty dang similar weights, so I'd say you're near truth. It'll get corrected in the end like you said.

*Note on Revisions: For the official documents that circulate in my line of work, things start as Rev NEW, then Rev A, B, C, etc......

 

[les]

First side of fillets. Used Rocketpoxy. Had to use some tools for in between the rings.



Common Info

Thought I would show the different nose cone profiles

The Semroc is scale. It has multiple angles.
Q model is elliptical
Wildman is pointed



END COMMON INFO

 

[les]

Finally finished the fillets! Sort of - need to do a little clean up



Drilled and tapped the holes for the coupler. #6 for the metal screws to the top, #4 for the shear pins for the bottom. I did the holes in line with the fairings. I found there was a little play with the coupler, so I clamped some angle irons to help keep the tubes in line while drilling. The tape helped keep the angles in place while trying to clamp them in place.



Based on the Rocksim, no nose weight will be required. I scuffed the nose cone and coupler and epoxied them together.

 

[les]

What are the remaining tasks?
Miles of tape masking and fillets (or just looks like it will be miles) - DONE
Drill & tap holes for coupler/Avbay - DONE
Build Avbay
Install rail buttons
Complete Rocksim update - see if weight will be required in nose. I started with a Rocksim file from Rocket Reviews, used the 3X scaling feature, then been correcting to match this version. - DONE
Glue coupler to nosecone - DONE
Recovery retention for lower body (I have some weird ideas for this)
Prime & paint - will need to reconfigure my shop like I did for my L3 rocket as it won't fit my normal spray area

Clean up details
Drill and tap holes for nose cone

 

[les]

Rail button discussion.
First - quantity vs placement
- Just doing two on the sail - I feel are these would be too low and too close together.
- Again, doing two, one on the fairing and one on the sail - good separation, but unless you have a real long rail, the top one may leave the rail with only one button left before the rocket is at sufficient speed. To the bottom of the fairing is about 44". Most likely the button would be at the 45" mark. With the rocket a bit off the blast deflector you will loose nearly 4' of rail.
- Go with 3 buttons: 2 on the sail + 1 on the fairing. Appears to be the best of both worlds, but need to ensure all 3 are in alignment.....

Thoughts/Comments?

 

[Wally Ferrer]

I'm planning to do two on the sail and one on the fairing, still a little concerned about spacing to have the rail clear the rings and still hit a button on the fairing. Your numbers indicated it will be tight. I have a rail, so I'll be able to use that to ensure alignment. Without it, a piece of string might do...

 

[les]

Also starting to think about deployment. I tend to be a bit conservative on deployment charges.
The drogue chute just has the lower small tube - 2.25"D x about 60" long. In actuality, with the motor volume and coupler extending 3" into the tube, it will be less, but there is my conservatism. Total volume is then about 240 cu-in. 15psi will provide about 60lbf and needs about 1.85g of FFFF. This has to shear the two #4 nylon plus get the laundry out. Seems a little wimpy.
20 psi will generate almost 80lbf and requires about 2.5g.
For the main, we have 2 size tubes. Since we have to separate the cone with a 3.125"D, I will calculate the equivalent volume of the small tube. The actual large tube is 3.125"D x 23"L. The small tube is 2.25"D x 40"L. This works out to an equivalent of a 3.125"D tube that is about 21"L. Adding the 21"+23" = 44". Since there is a larger surface area for the cone, at 15psi there will be 115lbf and requires 2.4g of FFFF. This should be sufficient, but obviously need to ground test....

For a charge canister, there are the 3g Rocket Junkies unit or 4.5g Mac Performance. If 2.5g is required, I would lean toward the 4.5G canister as it gives more leeway if I need to grow - plus I generally have a backup charge that is larger (the blow it out or blow it up backup). If the primary works, the charge is into open air. If it failed, I want a bigger "boom" to ensure it works.
Hmm - just checked specs. One is 3/4"D x 1.125"L and the other is 3/4"D x 1.125"L.
Since both are the same size, why does one hold 50% more charge than the other????

Please double check my math..............

 

[Nytrunner]

Is it abaolutely necessary to pin the apogee break? Also, #4 pins take about 45-50 lbs Each to break. If you do pin the apogee section, I recommend either switching to #2 nylon screws, or increasing your charge strength (actually I recommend increasong drogue charge regardless. #2 pins take about 25-30 lbs to break, so 60 lbs is marginal)

What size and number of pins are you using for main?

 

[les]

Is it abaolutely necessary to pin the apogee break? Also, #4 pins take about 45-50 lbs Each to break. If you do pin the apogee section, I recommend either switching to #2 nylon screws, or increasing your charge strength (actually I recommend increasong drogue charge regardless. #2 pins take about 25-30 lbs to break, so 60 lbs is marginal)

What size and number of pins are you using for main?

My concern is drag separation - and there is a lot of drag on the lower section!
I had debated with myself between #2 and #4 shear pins. I went with #4 due to the expected high drag, but with the small diameter you don't get a lot of force for the separation. Agree with changing to #2 (quantity 2 - missed that in original post)

I'll also use #2 for the cone (easier to use the same part everywhere)

 

[les]

Updated shear pins to #2

Did a bunch a fiddling and finally installed the 3 rail buttons.
I used a long level to try to keep the 3 in line

The one on the fairing is a close to the rod as I dared. There will be some, but not a lot of, clearance between the rail and the rings (< 1/8")



Note - at least with the FG parts, the rod is thicker than the fairing/fin. The rail buttons I have are the 3 piece units, instead of just 1 piece. I sacrificed some so I could but a second washer to lift the button up.

 

[Wally Ferrer]

I've been considering doing the same thing, for the same reason.

 

[les]

Now for my harness retention for the lower body.
I said I had a weird idea for this.....

I had some scrap 1/2" plywood. Using a fly cutter, I cut a centering ring to fit the smaller tube.
I took a bolt and cut it to a little less than the diameter of the ring.

My plan is to epoxy the cut bolt to the ring and install into the tube. The bolt will be on the bottom of the ring. In my pix, the ring/bolt is upside down. I also made a small notch where the bolt will go...
I'll then "thread" a kevlar loop down and around the bolt. The two ends will exit the top of the tube. If I have a long enough piece, it will connect directly to the Av Bay. If not, I'll attach another piece between its ends and the Av bay

If I ever want to inspect or replace this loop, it will be a simple matter to pull the existing cord and thread a new one in.

This will allow me to use the engine ejection as a backup.
And yes, I know I could buy something equivalent, but except for the bolt and a bit of time, this cost me nothing......



I know I could