Boris Katan flights 2015 -> Clusters are Fun <-

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CMASS Launch - 8/8/2015 - Amesbury, MA
40 motors burned in two flights


It was a very nice day for flying rockets.
Sunny, 70's F, low winds for most of the day.

The TOGinator had been prepped for LDRS, but rain postponed its launch until today...

30 motor cluster:
27x Estes D11-P +
2x CTI G54 Red +
1x CTI H87 Imax


Slightly less than 500Ns BP + 500Ns AP = mid J cluster

The TOGinator lifted off quickly, firing all 30 motors.
A bright fan of flame and smoke behind it.

Rotated several times on the way up to 1324 ft.
Ejected 7 ft main chute at apogee as planned and recovered well on the field.

Used my cluster box and Rocketflite CF igniters for all motor ignitions today with success, also used CF's for TOGinator's two 2.5g ejection charges.
Prepared and tested series strings of 2 or 3 CF igniters before the launch, with single CF's in the 3 AP engines.
Then taped igniters in place, using extra tape to assure igniters stayed in place.
Triple-checked arrangement and wiring of igniters.

While the TOGinator is build to support dual deploy, I intentionally did not put in shear pins, so the rocket separated completely at apogee deploying main.
Flight was not going very high and second ejection charge served as a backup for main chute deployment.

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My second and final flight of the day was the Spinning Saucer of the Apocalypse.

10 motor cluster launched on:
8x Estes D11-P (for spin) +
2x CTI G68 White (for lift)

Lots of spinning flames and very smokey.

A couple little boys were very interested in the saucer, so I told them there were little green men inside it with ray guns.
Figured they needed to know the truth, or at least needed some practice determining when they should take literally what someone says to them...:dark:

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In the pad video of the TOGinator liftoff and also in 3rd and 4th pictures in the TOGinator post above, can see that the igniters, cluster box leads and the cluster box itself got a pretty firm yank upwards by the rocket...

Launch Video:

[video=youtube;RB1tg_Pj3BM]https://www.youtube.com/watch?v=RB1tg_Pj3BM[/video]
 
Very cool Boris, great videos!

Thank you.
Pulled in content from 2 onboard video, 2 ground video and 2 ground still cameras.
Used the stills to make up for the less than optimal handheld video.

At the field, a gentleman I had not met before looked at the TOGinator with its hairball of igniters and said "you must be Boris".
Not sure whether to be flattered or just accept that i'm pushing one corner of the the nerd envelope.
I'll go with both.
 
CMASS Launch - 8/22/15 - Acton, MA

Weather was dubious. Raining as I left my home in Fairhaven, MA.
Rain had stopped 1.5 hours later as I arrived in Acton. Then gradually cleared over the course of the day.

I flew the Turbine Rocket Saucer on a cluster of D11-P's and launched Naked Finn's Canadian Arrow twice on CTI G68 White loads.
As these flights were very similar to recent previous flights, kept things simple and didn't take pictures or video.
 
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At the recent Amesbury launch, I was seduced by the Mad Cow 2.6 Inch Bomarc kit offered for sale by AMW.

It is a scale kit, the real Bomarc was a clustered missile, lots of nice parts in the kit, and it is a size that can be flown in many venues.
So I took it home with me...

The kit spec is 2.6" diameter x 45" long x 39 oz.
The two ramjets are 2.2" diameter and are mounted less than an inch from the main body.

So clustering this beauty is very doable.
I had a 4 x 24mm cluster motor mount already built for a project never completed.
Already had central motor retention and FlisKits baffles.
This will go in the main body tube.

Will add 2 x 24mm motor tubes in each of the ramjets for a total of 8 x 24mm motor tubes.
The pylons that connect main body to ramjets will be built larger and stronger, plus through the wall at both ends, to keep everything together under boost.

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Started by building up the main wing.
Bonded two sections of 1/8" ply.
Spray cans and aluminum plate used to press sections flat while glue dries.
Also some minor repair of Naked Finn's Canadian Arrow after removing it from the tree at Acton 7/25/15 launch.

> Planked top of wing with strips of 1/8" balsa.
> Air foiled wing and sanded tail fins.
> Built up top section of airframe from multiple sections of balsa. Used CA to get this done quickly.
> Sanded them to nice rounded aerodynamic profiles as specified.

Other than cluster motor mounts, stronger ramjet pylons and a thin external shell of fiberglass (2x layers of 1oz glass), I plan to build this kit as the instructions specify.

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Bomarc build is progressing well.

pic 1: Ordered 4x 24mm into 2.6 inch cluster centering rings from LOC.
Used these and Locktite 5 minute epoxy to install motor mounts into main body tube.
Glued together pairs of 24mm motor tubes for outboard engines.

pic 2: Epoxied (slow West epoxy) Kevlar 1/4 strap into coupler used join the two main body tube sections.
Laid 2 layers of 6 oz glass at base of strap for strong retention point.
Wrapped Kevlar with masking tape above epoxy bond point but below where the Kevlar will exit centering ring and be called on to flex.
This reduces Kevlar threads breaking at the edge of the epoxy.

pic 3: Had previously built up over sized ramjet pylons with 6" x 1/4" balsa in center and 2" x 1/4" basswood at both ends.
Expanded slots in ramjets to receive these and bonded them through the wall to pairs of 2x 24mm motor tubes.

pic 4: Wrapped both ramjet units with 2x layers of 1oz fiberglass.

pic 5: After bonding together main body tube sections, epoxied this to built-up wing assembly.

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Bowmarc build is progressing well.

pic 1: Ordered 4x 24mm into 2.6 inch cluster centering rings from LOC.
Used these and Locktite 5 minute epoxy to install motor mounts into main body tube.
Glued together pairs of 24mm motor tubes for outboard engines.

pic 2: Epoxied (slow West epoxy) Kevlar 1/4 strap into coupler used join the two main body tube sections.
Laid 2 layers of 6 oz glass at base of strap for strong retention point.
Wrapped Kevlar with masking tape above epoxy bond point but below where the Kevlar will exit centering ring and be called on to flex.
This reduces Kevlar threads breaking at the edge of the epoxy.

pic 3: Had previously built up over sized ramjet pylons with 6" x 1/4" balsa in center and 2" x 1/4" basswood at both ends.
Expanded slots in ramjets to receive these and bonded them through the wall to pairs of 2x 24mm motor tubes.

pic 4: Wrapped both ramjet units with 2x layers of 1oz fiberglass.

pic 5: After bonding together main body tube sections, epoxied this to built-up wing assembly.

Oh man, this is going to be cool.
 
At a recent Acton launch, Howard G. brought in the pieces for his custom 8 inch monster Talon kit for show and tell.
This will be a beauty when it all comes together and flies for his L3.

I have already volunteered to be a part of the support crew when the day comes.

We had some kids and even some adults ask if that rocket was going to fly that day in Action.
The rocket was obviously not assembled and Action is a low-power launch.
The level of disconnect many people have from the world around them is disconcerting to say the least.

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The pod pylon mount to the main body tube is a real weak spot on the stock kit even for decorative pods. But now they are going to be POWER PODS! COOL. Are you going to use the stock quarter inch launch lugs?
 
The pod pylon mount to the main body tube is a real weak spot on the stock kit even for decorative pods. But now they are going to be POWER PODS! COOL. Are you going to use the stock quarter inch launch lugs?

I will use rail buttons for more stable liftoffs.
Plan to put them on one side of the rocket so that it can be launched with all motor flames in unobstructed view.

I agree that the stock kit ramjet pod mounting setup is not very strong.
Even without motors in the pods, it would be better to use through the wall pylon attachments.
 
pic 1: Covered airframe with 2x layers 1oz fiberglass, except upper body tube which has 3-4 layers.
Pre-cut 10 pieces of glass. Due to summer heat, resin set up more quickly than usual, had to make 5 small batches.
Some edges already trimmed.

pic 2: After 2 hours of sanding, followed up by some touch-up resin application.

pic 3: Through-the-wall booster pylon attachment to main airframe. Longer tab bonds to a short central run of 29mm tube, which was originally intended to be motor mount for kit.
Short tab to the back bonds to 4x 24mm cluster motor mounts. Short mid-section tabs coated with several build ups of epoxy as these are free standing and exposed to ejection gasses.

pic 4: Made 2 equal length sections of (temporary) posts to assure symmetric positioning of ramjet pods, plus plenty of aerospace tape :) to keep it all in place for TTW bonding.

pic 5: Filleting one side of both ramjet pylons. Last 2 steps done with West 206 epoxy thickened with silica.

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Very cool Boris. You gonna shoot missiles out of those pods? :)


This will be interesting flight - especially with the thrust coming from the two pods - maybe need more than CP and CG ... Might need moment center lol. Are you worried about the push from this 4 motors might give the flight a different trajectory?
 
When launching with power pods you have to be in the moment, knees bent, eyes on the prize and heads up. When they all light it is a precious moment.

I close my eyes
Only for a moment and the moment's gone
All my dreams
Pass before my eyes with curiosity

Toto, we are not in Kansas anymore!


With all those motors burning just a tiny bit differently you hope all the sin is adequately spread out before it leaves the rod or rail.

Trust in thrust.

Clusters are fun!
 
This will be interesting flight - especially with the thrust coming from the two pods - maybe need more than CP and CG ... Might need moment center lol. Are you worried about the push from this 4 motors might give the flight a different trajectory?

You raise a good point. The motors in the booster pods will generate some off center thrust.

Several factors will moderate that effect:
> all motors will be Estes BP, so they will have a thrust spike at the start of the burn - both burning off Ns and gaining speed - while the rocket is climbing the rail and in a held straight up position
> pod motors are only a few inches off center, whereas the rocket is 45 inches tall and will have a lot of motor and nose weight - mass at ends = more force required to rotate
> as the rocket builds up speed, the large wing in combination with the lower fins will resist the tendency of the rocket to arc

Also:
> the rocket will be positioned on the rail so that the pods face the spectators, so any flight arc due to pod motors will be away from aforementioned spectators

Without a doubt, first flights on complex cluster projects are always interesting...
 
The airframe is completed other than one more fillet on a ramjet pod and the rail buttons.

So I loaded recovery and engines and checked rocket CG.
Then taped a small bag of lead shot to tip of nose cone adding 3oz at a time and re-checking stability.
I became concerned when 12oz of nose weight still put CG behind kit recommendation.

Kit instructions specify that recommended CG is 23.5 inches from front tip of NC.
This seems extremely conservative, as it is at the top of the large wing and very close to the middle of the rocket.

Did some research and found a few TRF posts that seemed to suggest stock builds were adding somewhere around 6oz of nose weight.
With about 7oz added by the thin fiberglass shell on the airframe, and the additional weight of clustered motors, 12oz seemed about right.

Downloaded a RockSim of this kit and adjusted its weight and CG to match actual measured values on my modified build.
This and one forum post put CP at 30.9 inches from front.
This same RockSim model shows 2.29 calibers of stability with 12 oz on nose weight, so this is what I went with.

pics:
Drilled holes in NC tip and rinsed NC inside with alcohol to enhance epoxy bond.
Then wrapped NC tip with wax paper and tape and poured 1oz epoxy and 12oz lead shot into NC

Drilled a large hole in base of NC to pour in epoxy and shot, and also to tie harness through.

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Hardware store Lock Tite epoxy will not stick at all to the waxy HP nosecone. After the horror stories I have heard about these things loosing nose weight and reading the directions I got out the drywall screws.
 
I always use West 206 slow epoxy for nose weight. Adheres better and mixes more easily with lead shot. Have had good luck with epoxy rivets. Also important to wash plastic surface with alcohol.

So far have only dislodged nose weight at the end of a ballistic recovery event.

I agree that 5 minute Locktite really needs porous surfaces for a good bond.
 
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pic1: Attached rail buttons with my new favorite method.
T-mount button from AMW surface mounted. Sand T then clean with alcohol. Bond with slow epoxy and 3+ small squares of light fiberglass.

pic2: Put extra epoxy on NC rivets as some did not fill completely to surface.

pic3 and 4: Originally planned to paint the Bomarc as the real missiles appeared.
However, I liked the appearance of the wood covered with a thin layer of fiberglass, so decided to leave all wood exposed and just paint tubes and NC.

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I am pleased with its current appearance.

It did end up heavier than I expected.
Airframe and nose cone are 57 ounces.

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Decided to add a couple more motor tubes because:
> rocket build came out a little heavier than I had expected, +2 motors gets flight sims back up around 800ft
> balances out off-center thrust from ramjet motors
> looks cool
So first flight will be on 10x Estes D engines.

> wrapped 24mm LOC cardboard tube with 3x layers 1oz fiberglass
> cut front of motor tube sections at 30 degree angle
> masking taped 1/4in wide strip and painted motor tubes same dark blue as all other tubes in this build
> removed masking tape and rough sanded bond points
> bonded tubes with West 206 slow epoxy thickened with silica

> Also painted entire exterior of rocket with clear gloss to get more shine, particularly from areas not already covered with color

Flight weight will be about 4.8 lbs:
5 oz nosecone before nose weight
17 oz nose weight
5 oz chute/harness/Nomex
28 oz airframe before fiberglass
7 oz airframe fiberglass shell
15 oz for 10x D engines

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CMASS - 9/26/2015 - Amesbury, MA
FlisKits Anniversary and Bill Spadafora Memorial launch

Two 10 motor clusters, plus a two-stage 10 way Frick-n-Frack drag race


It was a nice Fall day, sunny with a high about 60F.
Was a bit windy, but that is common this close to the New England coast.

The Bomarc lifted off on a column of BP smoke with multiple flame clusters for a great first flight.

Went up arrow straight to about 600ft on:
6x D11-P and
4x D12-5
Equivalent to a 176Ns H114

Chute deployed cleanly for a good recovery.
It did appear to drop a bit more quickly than I would have preferred, may go for a larger chute next time.

For launch, positioned the Bomarc so that ramjet pods faced spectators and narrow edge of wing (least surface area) faced crosswinds.
Rocket was very stable with this motor load.
May try 4x E9-6 and 6x D11-P next time, to enjoy a longer central burn and get a little more altitude.

Rocket is in perfect shape after first flight.

Launch continued on next page.

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