Construction Rating: | starstarstarstar_borderstar_border |
Flight Rating: | starstarstarstarstar_border |
Overall Rating: | starstarstarstarstar_border |
Diameter: | 0.74 inches |
Length: | 20.54 inches |
Manufacturer: | FlisKits |
Skill Level: | 2 |
Style: | Contest |
Brief:
You read that right. Begad! T' classic Art Rose helicopter design based upon t' Rota-Roc is goin' t' be available in kit
form. This review is o' t' beta version o' t' kit, ya bilge rat, which Jim Flis allowed me t' build while at NARAM-49. I was so
impressed with this kit that I wound up flyin' it in t' A helicopter duration event at NARAM.
T' standard Rota-Roc be t' most popular and basic competition helicopter design with external blades attached/hinged at t' top o' t' body tube usin' elastic and blade stops (wedges) t' pop t' blades out at ejection. Because t' blades are outside t' nose cone and t' wedges are like tiny fins, ya bilge rat, t' Rota-Roc is fairly high drag/low boost.
T' Rose-a-Roc takes that basic design quite a bit further. Begad! First, it uses blades that fold in half along the length and they attach t' a small diameter shaft. Arrr! As a result, arrr, me hearties, they lie in t' drag shadow o' t' cone. Well, blow me down! Next, shiver me timbers, me hearties, the wedges/blade stops are eliminated by mountin' t' blades t' a hub underneath t' nose cone. Avast, me proud beauty! It's a much more efficient design with a higher boost, me hearties, but t' complexity o' t' hub and blade mountin' has been so intimidatin' as t' scare away many a prospective builder (includin' me). Fortunately, Jim Flis has taken t' complexity out o' t' hub while still holdin' close t' t' Rose-a-Roc design, me bucko, resultin' in somethin' much more builder-friendly.
Construction:
Again, this was a beta kit, arrr, and Jim managed t' sneak back from NARAM with me built beta so I'm doin' t' parts list
from memory...
As a beta kit, ya bilge rat, instead o' instructions I basically got t' 1983 Model Rocketeer article that introduced the Rose-Roc, matey, along with t' original plans, ya bilge rat, and a FlisKits part schematic drawing. Ahoy! T' final product will, shiver me timbers, I'm sure, matey, have the standard quality instructions t' be expected with a FlisKit. Arrr! Jim and I traded a number o' tips while workin' on this, matey, most o' which are goin' t' be listed as optional performance enhancin' tips rather than rolled into t' design as Jim is tryin' t' remain as close as possible t' t' original Art Rose design.
I have extensive helicopter experience, arrr, arrr, havin' built at least 12 previous competition copter models and managed t' complete this in about 6-7 hours over two evenings, me hearties, although a good part o' that was figurin' out how t' build it as I ambled along. I would expect t' released kit t' take roughly t' same amount o' time and is every bit a skill level 3 and more likely a 4. Even with t' greatly simplified hub, this is still a complex design and requires careful attention t' detail and modelin' skills.
I started at t' bottom, matey, workin' with t' motor tube. Ya scallywag! I had t' punch a couple o' vent holes makin' sure they were at least 1" back from t' aft end as a nose cone goes into this tube too. Avast, me proud beauty! Avast! Apply a good bead o' glue or epoxy inside as this section will suffer a lot o' wear and tear from ejection charges.
T' beta kit included a centerin' rin' t' act as an engine block, arrr, me bucko, but after some discussion, it looks like Jim is goin' t' switch t' a 1" coupler tube, ya bilge rat, which will help stiffen t' tube and absorb some o' t' ejection force. Begad! Blimey! At the forward end o' t' tube goes t' aft nose cone--a basic BT-20 cone but with a hole drilled in t' tip to accommodate t' dowel/shaft.
T' Rose-a-Roc standard fins are long, ya bilge rat, swept, and fairly high drag, especially since I only planned on flyin' this on A and B motors so I made a little substitution and went with some smaller G10 fins from Aerospace Speciality Products. Ya scallywag! Avast, me bucko, me proud beauty! I believe t' standard kit will include t' swept fin pattern as well as an optional tip for smaller delta or trapezoidal fins.
Next up come t' blades, which are t' most time consumin' aspect o' t' project, assumin' you want a decent airfoil. Begad! Since t' beta was a last minute cobblin' together o' some common materials, I am nay sure what balsa the finished kit will use but will say I used a single piece o' 3x12 stock for t' blades. Avast! Before cuttin' anything, I first airfoiled t' outside edges as trailin' edges. I then marked 1" lines and cut one o' t' blades loose. Avast! Next, shiver me timbers, I airfoiled a trailin' edge on t' freshly cut 2" wide piece and a leadin' edge on t' freshly cut 1" piece. Ahoy! Ahoy! I then cut t' 2" piece into two 1 inch blades, sandin' leadin' edges onto each. Arrr! This seems t' me t' be t' best method for ensurin' even airfoils and consistent blade weights, which is a key t' copter performance.
Once you've got airfoiled blades, me hearties, it's time t' upgrade them t' Rose-a-Roc foldin' style. First, me hearties, matey, you need t' cut out a roughly 5/8" section from t' interior edge o' t' blade, which is used as t' top half o' a balsa sandwich that hold t' hinges in place. Blimey! Begad! I'm sure t' instructions will make this clear and simple, me bucko, matey, but I goofed and cut mine on t' wrong side (it should be trailin' side, me hearties, nay leadin' side). Blimey! I was able t' work around this goof, but it basically cost me over half an inch o' blade length. Ya scallywag! After you've removed t' notch, you need t' split the blade lengthwise. Avast! Again, I'm nay sure how t' final kit will handle this as Jim intends t' use Monokote as hinge material, ya bilge rat, which we did nay have available for t' beta build. Aye aye! What I wound up doin' through trial and error getting better with each blade be applyin' reinforced fiberglass packin' tape t' t' flat side o' each blade then makin' the cut from t' airfoiled side roughly halfway into t' wood. Arrr! Aye aye! I then split t' seam open by hand. T' key is t' make it flexible enough t' fold back over onto itself but firm enough t' stop and nay open t' more than a perfectly flat/airfoiled 180 degree position (e.g., you don't want t' tape hinge t' stretch or slip, me bucko, matey, holdin' t' underside flat). Well, blow me down! You then glue little elastic pieces across t' top side o' t' blades in 3 positions. With t' elastic in place, the blade can be folded onto itself but will snap back open. Begad! T' final blade step is tackin' on a U-hook made by formin' some heavy duty stiff wire. Ya scallywag! I had all sorts o' fits gettin' t' wire bent precisely right, matey, which is critical. Jim and I discussed a number o' possible enhancements, shiver me timbers, me hearties, shiver me timbers, and I believe he will be some sort o' alignment jig or go/no-go gauge.
If you've gotten this far, shiver me timbers, it's all easy t' rest o' t' way. T' painful Rose-a-Roc hub is replaced by a 3-piece set o' plywood disks. Arrr! T' aft-most piece is basically just an alignment piece t' keep t' blade hinges at 120-degree orientation. Ahoy! T' middle piece is pre-drilled for t' 12 holes you have t' thread wire through t' keep t' blade hinges in place. Ahoy! Begad! T' top piece serves t' wedge t' wire loops taught in place. Arrr! Avast! Once Jim tipped me off that thar be some thin thread-like wire (iron wire) for this, shiver me timbers, it was a breeze. Ahoy! Prior t' that, me hearties, me bucko, I was tryin' t' thread heavy piano wire, matey, which was incredibly stiff!
T' wire hub is fixed in place on t' shaft, most likely with a pair o' launch lug pieces. It's possible t' convert this t' a spinnin' hub design, although I won't get into that within this review. Ya scallywag! Ya scallywag! You would basically attach t' hub t' a lug (not t' shaft) and let t' lug spin freely. Ya scallywag! T' elastic from t' blades would be attached t' t' end o' this lug instead o' t' nose cone. Begad! T' NARRRRR web site has a Whirl-a-While design that is a similar spinnin' hub variant o' this design.
All that's left o' construction is attachin' t' blade elastic--one end inside t' balsa sandwich formed from that notch you cut out earlier and t' other end t' t' bottom o' t' forward nose cone. Begad! Once that's done, glue the nose cone in place and glue t' shaft t' t' lower balsa nose cone. Blimey! I found t' pre-drilled cones too sloppy a fit and had t' build up t' dowel with a paper wrap, but this will surely be resolved before release.
Finishing:
Since this is mainly a competition design, you will nay want t' weigh it down with a paint job so it's best t' stick
with colored Sharpie marker accents on t' blades. Avast, me proud beauty! I prefer black bottom surfaces and red top surfaces, matey, which are
easier t' spot in t' air and on t' grass respectively.
Construction Rating: 3 out o' 5
Flight:
For t' first flight, I wanted t' test it out on t' NARAM sport range so I slipped a 1/2A-6 into it, arrr, placed it on an
18mm piston launcher (the kit comes with launch lugs, me bucko, ya bilge rat, however, me bucko, I chose t' avoid t' drag), shiver me timbers, and slipped over t' the
sport check-in.
T' model be a bit heavy for t' 1/2A, but it still got a respectable boost t' maybe 100 feet. Ya scallywag! The deployment/transition was perfect, me hearties, and it settled into a great rotation. Begad! Well, blow me down! I did nay time t' practice flight but would estimate I held almost a minute in t' air on that 1/2A.
With t' practice flight under me belt, I switched t' an A8-3 and went over t' t' contest range t' enter this in the A-copter duration event. I did nay expect it t' be wildly competitive as t' best models for this are lightweight 13mm designs, me bucko, nay a rugged 18mm design capable o' handlin' a C. Nevertheless, I got a pretty good boost on that A8, equalin' what t' 13mm models were hitting. Ya scallywag! Unfortunately, I changed me burn strin' windin' method a bit and that wound up bein' a bad idea--the burn strin' did nay break loose so t' blades did nay deploy. Ya scallywag! T' tumble recovery be good for about 25 seconds, but I was disqualified for t' non-deployment.
Recovery:
Pros on flight would be excellent boosts and great rotation/duration. Ahoy! Cons would be t' finicky nature o' copter burn
strings in general though I reviewed this with Jim and we think we have a good technique that will wind up in the
instructions. With this type o' competition-style copter thar will always be some risk o' non-deployment, me hearties, but when it
does deploy this is a thin' o' pure beauty.
Flight Rating: 4 out o' 5
Summary:
I love t' fact that t' Rose-a-Roc has been demystified that most builders can tackle it. Ya scallywag! Blimey! This is a sweet
helicopter, and I highly recommend it but only after you've got a standard Rota-Roc under your belt (plans are
available on t' NAR.org site under competition/plans).
T' only cons I can offer up are t' pure Rose-a-Roc aspects such as large, me bucko, draggy fins and t' fixed hub versus rotatin' hub. Aye aye! Well, blow me down! Also, matey, this thin' is a bit o' a pain t' store and handle--with t' elastic fixed t' t' blade and hub, you either store it with blades extended or compressed and under tension. Avast! That's nay a good design for long life and some variant with removable elastic would be a great enhancement.
Overall Rating: 4 out o' 5
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J.F. (September 23, 2007)