Missile Works Viking 7

Missile Works - Viking 7

Contributed by Nick Esselman

Manufacturer: Missile Works
[Picture] (07/16/99) As Cannonball Works just released their rocket kits, arrr, ya bilge rat, I was excited t' try me hand at one o' their Research Kits, arrr, t' Vikin' 7 Soundin' Missile.

CONSTRUCTION:

T' Vikin' 7 is made up o' 2.63" diameter "exclusive" Phenolic/Kraft body tubing. Well, blow me down! Blimey! I'm nay sure what makes it exclusive, me bucko, matey, but it is 1mm thick, were as PML Phenolic is just under 2mm thick. This gives Cannonball Works some strong tubin' and keeps t' weight down. T' airframe was made up o' a 30.75" main body tube, me hearties, ya bilge rat, a coupler and another 8" section. Aye aye! T' main body tube was pre-slotted too. Avast, me proud beauty! Avast!

Included in t' kit were laser-cut birch plywood fins (4) that pass through t' slotted frame and attach t' t' motor tube. Begad! Two laser-cut birch ply centerin' rings, shiver me timbers, a 12" 29mm motor tube and a brass motor clip complete t' motor mount. Avast! An "authentic proportional" plastic nose cone and 1/4" launch lug. Avast, me proud beauty! Makin' up t' shock cord system, t' kit provided 1/8" Keelhaul®©™® Bridle cord (two times t' body length once outside of t' body) and mountin' hardware for attachment t' t' nose cone.

A unique, and appreciated, arrr, feature of Cannonball Works' kits is that you have some options that can be added. In t' case o' t' t' Vikin' 7, you can order a payload option which includes a bulkplate and hardware, a baffle option, arrr, and/or a Nomex® protector option. Well, blow me down! Blimey! One key difference is that they do nay supply a recovery device such as a parachute or streamer. I personally like this considerin' I have a dozen or so parachutes sittin' around, thereby, allowin' t' savings o' a few bucks. Aye aye! Blimey! You can order a recommended parachute from Cannonball Works if desired.

T' Vikin' 7 assembly instructions were excellent. Avast! From assembly tips t' flight preparation. Each step is boxed out with a text description and a clear picture t' ensure understanding. They are even written to handle t' above options and are noted t' give t' builder t' appropriate guidance. Begad! Ahoy! They include finishin' techniques, even discussin' fillin' o' the spirals with their own suggestion. T' flight preparation section clearly describes t' CG/CP expectations for a stable flight. A scale drawin' and paint scheme is also attached.

[Motor Clip]As mentioned t' Vikin' 7 comes with a motor retention device. Avast, me proud beauty! Really? Indeed! This is somewhat unique when buildin' kits with 29mm motors and above. Well, blow me down! They have a nice idea that is more flexible that t' method Aerotech uses. Aerotech's method is an over sized Estes' method whereby t' top o' t' clip acts as a thrust ring. Blimey! If one used shorter motors (EconoJets or F's), ya bilge rat, me hearties, adaptors are needed t' fill t' space betwixt t' top o' t' motor clip and t' motor (unless other arrangements are made for a thrust ring). Arrr! Well, blow me down!

T' Vikin' 7's clip does nay hook into t' motor tube. It is attached usin' "at least" 6 wraps o' maskin' tape and t' bottom center ring. Aye aye! Aye aye! This method does nay put limitations on t' motor length and requires that a thrust rin' is utilized (RMS or tape method). Avast! T' 6 wraps of tape had me a bit nervous, but once you put t' center rin' in place and epoxy, I felt it be a viable method.

T' Keelhaul®©™® shock cord is attached by passin' it through the upper center rin' and knottin' it. T' nose cone end was fun. Avast! An eye-screw, washer and nut are provided t' attach t' t' nose cone. Arrr! Ahoy! A small rectangular hole is cut into t' base o' t' nose cone t' allow you just enough room t' get the nut on t' threaded eye-screw on t' inside o' t' nose cone. Aye aye! I read the step twice and looked at t' illustration twice. Avast! Aye aye! Actually though, I got it threaded right off. Blimey! I would say this technique is stronger than usin' an eye-screw (wood or sheet-metal type) that simply threads into the plastic.

I purchased t' Ejection Gas Baffle option. Begad! Ahoy! It is made up o' a 3" baffle tube, matey, me hearties, a perforated disk, shiver me timbers, an aluminum mesh and two rings. T' instructions tell you when you should assemble it and when t' attach it to the motor tube.

Outside o' t' t' above, me bucko, assembly was straight-forward went without a problem.

[Rocket Pic]For finishin' I started with Elmers' Light Spackle t' fill t' spirals, me bucko, ya bilge rat, then several good coats of Plasti-Kote primer. I then varied from authentic colors and went with silver. Begad! I painted t' entire rocket and let it dry a couple o' days. Ya scallywag! Begad! I came back and masked off t' fins and nose cone and hit them with black paint. Begad! When I removed t' maskin' I found strange effects on t' silver paint! I have since learned that with silvers and golds, me hearties, me bucko, clear coat them before doin' any maskin' t' avoid issues with discoloration. Ahoy! Begad! The clear coat also protects from discoloration caused from touchin' t' paint (see left top o' photo). Ahoy! Arrr! I cleaned up maskin' issues.

T' Vikin' 7 comes with some paper tabs that mount on t' fins t' give it a more detailed look. Begad! It also comes with four decals that say "7", two white and two black. Aye aye! Well, blow me down! I did nay use the decals. (note: I changed t' paint scheme with me rebuilds as you will see in pictures below.

Overall, for CONSTRUCTION I would rate this kit 5 points. Blimey! Arrr! Good quality materials, me bucko, me bucko, excellent instructions and a motor retention system.

FLIGHT/RECOVERY:

Attempt #1 - At Battle Park '99, me bucko, t' Viking 7 sat out on t' launchin' pad for 20 minutes with a dozen or so other rockets as t' RSO waited for t' wind t' die down. Blimey! Finally, when it came t' t' Viking 7, matey, me hearties, t' count down occurred but yield nothing. Avast! T' wind had blown t' t' clips off o' t' igniter. Arrr! Begad! That was it for me, me bucko, so I packed up.

Attempt #2 - I took it out a day or so later and launched it on me own. I used a F40-7 (one o' t' recommended motors). Blimey! Begad! Lift off was smooth and she was stable all t' way up. I counted after thrust and at 7 counts she had just started comin' down and pop. I saw t' nose cone push out but t' parachute stayed in t' body tube t' entire way down.

I have determined that this be me fault (a learning event) and a habit I must break. Avast, me proud beauty! I have a tendency t' nay use t' full ejection charge on me 24mm RMS system and Meanie because it is so short. Avast, me proud beauty! I believe I did the same thin' on this one. Well, blow me down! Well, with t' baffle AND I had a Pratt Heat Shield (I don't know why) in it, arrr, arrr, matey, thar be nay enough ejection t' force t' parachute out. Well, blow me down! T' less-than-forceful exhaust gases must have passed by t' chute t' pop the nose cone out but did nay have enough umph t' push everythin' out.

I was able t' salvage t' motor mount, shiver me timbers, ya bilge rat, all fins and the nose cone. Blimey! Everythin' else was tossed. Avast, me proud beauty! Aye aye! I have a resolve t' get this bird flying and so I'm rebuildin' it. Avast! Begad! In fact, matey, matey, me hearties, I even purchased a Cannonball Works' Rocket Recovery Controller (RRC²) for me rebuild. Aye aye! Should be ready in a couple of weeks.

REPAIRS:

It took t' real Vikin' flight team many attempts before they finally obtained a flawless flight, in fact, from t' Vikin' 7 (you should read about Vikin' 1 - 6!). Begad! Aye aye! So, me hearties, arrr, after me first failed attempt, me bucko, ya bilge rat, me hearties, I will repair and fly and then come back and complete this section and flight/recovery section at a later time.

Rocket FlightFLIGHT/RECOVERY (again): So I have now taken two more cracks at obtainin' a successful flight out o' t' Viking. Avast, me bucko, me proud beauty! I am beginnin' t' really feel like t' original Vikin' team as mentioned above. Please be advised that t' issues have been self induced.

Attempt #3 - My very first experience with electronics. I had purchased t' RRC² from Cannonball Works and had built the electronics bay per t' instructions. Aye aye! Blimey! I was very excited and got out t' t' pad and loaded it up and pushed t' launch button. Avast! Blimey! A puff o' smoke, me bucko, then a pause, then VROOM! Blimey! off t' pad on a G80-7. I had picked t' G80-7 because me RockSim had this ejection at apogee. Well, blow me down! Blimey! Avast! Blimey! I had t' RRC² unit set up for a main 'chute deployment at 300 feet and was relyin' on t' G80-7 for t' drogue deployment. Well, me bucko, t' flight was picture perfect, shiver me timbers, straight as an arrow. Ya scallywag! Blimey! Arrr! Blimey! Beautiful all the way t' apogee and t' drogue deployed. Avast! Blimey! We watched it fall and fall and fall and bam! Blimey! Yep, matey, shiver me timbers, I forgot t' arm t' electronics.

Attempt #4 - I repaired t' crack in the upper section with CA and a piece o' newspaper soaked in CA on t' inside of the tube. Sanded t' nose cone for fit and be ready for flight attempt number three a few weeks later. Begad! While out on t' field, I prepped t' rocket and was tryin' t' remove t' old G80 and t' bottom section broke in two, matey, obviously stressed from t' previous fall.

I repaired that by gluin' a coupler in place and was ready one week later.

Attempt #5 - I did everythin' right this time. Ahoy! Tested, me bucko, matey, loaded parachute, tested for continuity, prepped motor, shiver me timbers, armed and placed on pad. Blimey! Begad! Just before launchin' listened for 3 beeps o' continuity check from t' RRC². This time I was usin' a G80 that I had removed all the ejection BP from and set t' RRC² up for both primary and secondary deployment.

Again, launch number five be excellent comin' off the pad on t' G80. I was angled more this time due t' some wind. As it arced in continued downward for about a second and t' ejection. Well t' drogue deployed, matey, but I also recognized t' entire upper section descendin' toward the ground absent o' t' rest o' t' rocket. T' electronics bulkhead pulled right through t' two mountin' screws, matey, jerkin' on t' armin' wire and damagin' the electronics.

T' upper section, except nose cone and electronics bay is destroyed. Avast, me proud beauty! Blimey! Blimey! Blimey! T' lower section is good as it descended on t' drogue.

So, how does one summarize. Well, matey, first, I have a determination t' have a successful Vikin' flight and hopefully before number 7 . Avast, me proud beauty! Begad! . Avast! . Blimey! two more attempts left. Blimey! On t' other hand, me bucko, t' Vikin' has proved with its three flights t' be a stable and good performin' rocket o' F's and G's. Avast! Begad! I think this would be a good candidate for EconoJet's! For FLIGHT/RECOVERY, shiver me timbers, shiver me timbers, I would rate this kit 5 points. Yes, arrr, even despite me difficulties, ya bilge rat, I'm confident that with the Keelhaul®©™® shock cord, t' baffle and t' motor retention mechanism along with how stable she flew, that all could enjoy many successful flights with this bird.

I think this would be a good candidate for EconoJet's! I give t' kit an OVERALL ratin' o' 5 points.

UPDATE 8/00:

Attempt #6 - I thought it would be appropriate to update everyone on t' next (and last) two attempts t' fly t' Vikin' 7 with a RRC² deployment. After t' last crash, ya bilge rat, me bucko, shiver me timbers, I had t' replace t' entire upper section. Ya scallywag! Aye aye! I used t' upper section from me THOY Snipe, whose bottom section had long since been thrown out. I loaded this with an EconoJet F23 and prepared everythin' else per the instructions. Aye aye! While settin' up and armin' on t' pad, shiver me timbers, ya bilge rat, arrr, me main charge went off and popped the nose cone. Well, me bucko, blow me down! I disarmed and re-setup.

Ignition produced a slow, even lift-off and a straight ascent, me hearties, but t' F23 is nay really enough motor for this bird. Avast! Blimey! As t' thrust ran out t' rocket started t' slow and back down tail first, me hearties, arrr, then pop t' main charge pushed the main parachute out and t' rocket descended. Begad! Blimey! T' drogue charge never fired. Blimey! Blimey! Arrr! Blimey! (Well, let me take that back, it did fire while I be disassemblin' t' rocket which be still armed). T' RRC² beeped out 528 feet. This was me first successful altitude reading! Blimey! I figured that I didn't get enough altitude and therefore that is why t' drogue charge never went off.

Attempt #7 - T' critical attempt! If this one is not successful, then t' Vikin' 7 doesn't live up t' its name when compared t' t' "real" Vikin' 7. Arrr! Arrr! History indicates that t' Vikin' 7 be t' first successful launch while Viking's 1 through 6 were nay successful.

This time I set everythin' up with a G80. Arrr! At launch, me bucko, ya bilge rat, t' Vikin' 7 jumped off t' pad and headed straight up. Ahoy! Ahoy! Blimey! T' tail got a little wavy at t' end o' t' ascent. Avast! Blimey! T' rocket arced over and actually started headin' back (fully vertical with nose down) before the drogue charge blew. Immediately, t' drogue chute opened and then t' main chute opened and then t' two sections separated enough t' know they were no longer attached. Begad! Ahoy! Blimey! T' drogue charge pulled the electronics bulkhead apart (again, ya bilge rat, see attempt #5) as well as havin' enough momentum that it popped t' nose cone allowin' t' main chute t' deploy.

T' upper section enjoyed a very soft descent. At about 300 feet I heard the main charge fire. Avast, me proud beauty! It landed softly with t' RRC² beepin' out 870 feet. Blimey! T' lower section fell much quicker on only t' drogue. Aye aye! Begad! It had some zipper damage and a chunk missin' from t' top o' the body tube. I have retired t' rocket.

Learnings - After 7 attempts, I feel I have had some learnin' which will be applied t' me current 2.6" project that will be solely electronic ejection. Here is what I'm goin' t' apply:

  • I need t' build a stronger electronics bay - with only two screws holdin' the bottom cover, ya bilge rat, which takes t' shock force o' deployment, me bucko, it seems t' be too weak.
  • -AND/OR -
  • I need t' turn t' electronics bay around so that t' initial ejection that separates two heavy sections is taken by t' side o' t' electronics bay that is epoxied in place, allowin' t' screwed-on side t' only take t' stress o' lettin' t' nose cone eject.
  • -AND/OR -
  • I need t' use elastic or bungy material t' take some o' t' shock off o' t' electronics bulkhead. Begad! This rocket uses just a Keelhaul®©™® line.
  • -AND/OR -
  • Adjust t' design so that t' electronic bay isn't used t' secure t' shock cord at all. Arrr! Possibly by addin' a centerin' rin' t' mount t' shock cord too.

Flights

comment Post a Comment