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FlisKits - Rose-a-Roc {Kit} (HC001)

Diameter:0.7360 inches
Length:20.5400 inches
Skill Level:2
Construction Rating:
Flight Rating:
Overall Rating:

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You read that right. The classic Art Rose helicopter design based upon the Rota-Roc is going to be available in kit form. This review is of the beta version of the kit, which Jim Flis allowed me to build while at NARAM-49. I was so impressed with this kit that I wound up flying it in the A helicopter duration event at NARAM.

FlisKits Rose-A-Rock

The standard Rota-Roc is the most popular and basic competition helicopter design with external blades attached/hinged at the top of the body tube using elastic and blade stops (wedges) to pop the blades out at ejection. Because the blades are outside the nose cone and the wedges are like tiny fins, the Rota-Roc is fairly high drag/low boost.

The Rose-a-Roc takes that basic design quite a bit further. First, it uses blades that fold in half along the length and they attach to a small diameter shaft. As a result, they lie in the drag shadow of the cone. Next, the wedges/blade stops are eliminated by mounting the blades to a hub underneath the nose cone. It's a much more efficient design with a higher boost, but the complexity of the hub and blade mounting has been so intimidating as to scare away many a prospective builder (including me). Fortunately, Jim Flis has taken the complexity out of the hub while still holding close to the Rose-a-Roc design, resulting in something much more builder-friendly.

FlisKits Rose-A-Rock

Again, this was a beta kit, and Jim managed to sneak back from NARAM with my built beta so I'm doing the parts list from memory...

  • 2 balsa nose cones, drilled for upper and lower
  • 3/16" wood dowel/shaft
  • 3 piece laser cut disk set (replaces the Rose hub)
  • 1/16" balsa stock for blades
  • 3/32" balsa fin stock
  • BT-20 motor tube (roughly 5" long)
  • CR520 centering rings
  • assorted wire/elastic for blade deployment

As a beta kit, instead of instructions I basically got the 1983 Model Rocketeer article that introduced the Rose-Roc, along with the original plans, and a FlisKits part schematic drawing. The final product will, I'm sure, have the standard quality instructions to be expected with a FlisKit. Jim and I traded a number of tips while working on this, most of which are going to be listed as optional performance enhancing tips rather than rolled into the design as Jim is trying to remain as close as possible to the original Art Rose design.

FlisKits Rose-A-Rock I have extensive helicopter experience, having built at least 12 previous competition copter models and managed to complete this in about 6-7 hours over two evenings, although a good part of that was figuring out how to build it as I ambled along. I would expect the released kit to take roughly the same amount of time and is every bit a skill level 3 and more likely a 4. Even with the greatly simplified hub, this is still a complex design and requires careful attention to detail and modeling skills.

I started at the bottom, working with the motor tube. I had to punch a couple of vent holes making sure they were at least 1" back from the aft end as a nose cone goes into this tube too. Apply a good bead of glue or epoxy inside as this section will suffer a lot of wear and tear from ejection charges.

The beta kit included a centering ring to act as an engine block, but after some discussion, it looks like Jim is going to switch to a 1" coupler tube, which will help stiffen the tube and absorb some of the ejection force. At the forward end of the tube goes the aft nose cone--a basic BT-20 cone but with a hole drilled in the tip to accommodate the dowel/shaft.

FlisKits Rose-A-Rock The Rose-a-Roc standard fins are long, swept, and fairly high drag, especially since I only planned on flying this on A and B motors so I made a little substitution and went with some smaller G10 fins from Aerospace Speciality Products. I believe the standard kit will include the swept fin pattern as well as an optional tip for smaller delta or trapezoidal fins.

Next up come the blades, which are the most time consuming aspect of the project, assuming you want a decent airfoil. Since the beta was a last minute cobbling together of some common materials, I am not sure what balsa the finished kit will use but will say I used a single piece of 3x12 stock for the blades. Before cutting anything, I first airfoiled the outside edges as trailing edges. I then marked 1" lines and cut one of the blades loose. Next, I airfoiled a trailing edge on the freshly cut 2" wide piece and a leading edge on the freshly cut 1" piece. I then cut the 2" piece into two 1 inch blades, sanding leading edges onto each. This seems to me to be the best method for ensuring even airfoils and consistent blade weights, which is a key to copter performance.

FlisKits Rose-A-Rock Once you've got airfoiled blades, it's time to upgrade them to Rose-a-Roc folding style. First, you need to cut out a roughly 5/8" section from the interior edge of the blade, which is used as the top half of a balsa sandwich that hold the hinges in place. I'm sure the instructions will make this clear and simple, but I goofed and cut mine on the wrong side (it should be trailing side, not leading side). I was able to work around this goof, but it basically cost me over half an inch of blade length. After you've removed the notch, you need to split the blade lengthwise. Again, I'm not sure how the final kit will handle this as Jim intends to use Monokote as hinge material, which we did not have available for the beta build. What I wound up doing through trial and error getting better with each blade was applying reinforced fiberglass packing tape to the flat side of each blade then making the cut from the airfoiled side roughly halfway into the wood. I then split the seam open by hand. The key is to make it flexible enough to fold back over onto itself but firm enough to stop and not open to more than a perfectly flat/airfoiled 180 degree position (e.g., you don't want the tape hinge to stretch or slip, holding the underside flat). You then glue little elastic pieces across the top side of the blades in 3 positions. With the elastic in place, the blade can be folded onto itself but will snap back open. The final blade step is tacking on a U-hook made by forming some heavy duty stiff wire. I had all sorts of fits getting the wire bent precisely right, which is critical. Jim and I discussed a number of possible enhancements, and I believe he will be some sort of alignment jig or go/no-go gauge.

If you've gotten this far, it's all easy the rest of the way. The painful Rose-a-Roc hub is replaced by a 3-piece set of plywood disks. The aft-most piece is basically just an alignment piece to keep the blade hinges at 120-degree orientation. The middle piece is pre-drilled for the 12 holes you have to thread wire through to keep the blade hinges in place. The top piece serves to wedge the wire loops taught in place. Once Jim tipped me off that there was some thin thread-like wire (iron wire) for this, it was a breeze. Prior to that, I was trying to thread heavy piano wire, which was incredibly stiff!

FlisKits Rose-A-Rock The wire hub is fixed in place on the shaft, most likely with a pair of launch lug pieces. It's possible to convert this to a spinning hub design, although I won't get into that within this review. You would basically attach the hub to a lug (not the shaft) and let the lug spin freely. The elastic from the blades would be attached to the end of this lug instead of the nose cone. The NAR web site has a Whirl-a-While design that is a similar spinning hub variant of this design.

All that's left of construction is attaching the blade elastic--one end inside the balsa sandwich formed from that notch you cut out earlier and the other end to the bottom of the forward nose cone. Once that's done, glue the nose cone in place and glue the shaft to the lower balsa nose cone. I found the pre-drilled cones too sloppy a fit and had to build up the dowel with a paper wrap, but this will surely be resolved before release.

Since this is mainly a competition design, you will not want to weigh it down with a paint job so it's best to stick with colored Sharpie marker accents on the blades. I prefer black bottom surfaces and red top surfaces, which are easier to spot in the air and on the grass respectively.

Construction Rating: 3 out of 5

For the first flight, I wanted to test it out on the NARAM sport range so I slipped a 1/2A-6 into it, placed it on an 18mm piston launcher (the kit comes with launch lugs, however, I chose to avoid the drag), and slipped over to the sport check-in.

The model was a bit heavy for the 1/2A, but it still got a respectable boost to maybe 100 feet. The deployment/transition was perfect, and it settled into a great rotation. I did not time the practice flight but would estimate I held almost a minute in the air on that 1/2A.

With the practice flight under my belt, I switched to an A8-3 and went over to the contest range to enter this in the A-copter duration event. I did not expect it to be wildly competitive as the best models for this are lightweight 13mm designs, not a rugged 18mm design capable of handling a C. Nevertheless, I got a pretty good boost on that A8, equaling what the 13mm models were hitting. Unfortunately, I changed my burn string winding method a bit and that wound up being a bad idea--the burn string did not break loose so the blades did not deploy. The tumble recovery was good for about 25 seconds, but I was disqualified for the non-deployment.

Pros on flight would be excellent boosts and great rotation/duration. Cons would be the finicky nature of 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 of competition-style copter there will always be some risk of non-deployment, but when it does deploy this is a thing of pure beauty.

Flight Rating: 4 out of 5

I love the fact that the Rose-a-Roc has been demystified that most builders can tackle it. 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 the site under competition/plans).

The only cons I can offer up are the pure Rose-a-Roc aspects such as large, draggy fins and the fixed hub versus rotating hub. Also, this thing is a bit of a pain to store and handle--with the elastic fixed to the blade and hub, you either store it with blades extended or compressed and under tension. That's not a good design for long life and some variant with removable elastic would be a great enhancement.

Overall Rating: 4 out of 5

    Flight Log

    DateRocket NameMotor(s)AltitudeNotes
    2007-07-31Chan Stevens's FlisKits Rose-a-Roc1/2A6-2- Great rotation and hang time, maybe 45-50 seconds.
    2007-07-31Chan Stevens's FlisKits Rose-a-RocA8-3- Piston-launched, good boost. No blade deploy--burn string failure and very weakened elastic ...
    2008-01-27Chan Stevens's FlisKits Rose-a-RocB4-2- Non-vertical flight path, piston tip-off
    2008-02-03 Moe Bertrand's FlisKits Rose-a-RocA8-3- 1st test flight. No rotor deployment=desert dart. All 3 blades separated at hub. Possibly ...
    2008-02-16Moe Bertrand's FlisKits Rose-a-RocB4-2- Again, my Rose-A-Roc did a Desert Dart and snapped all the blades off. I think the deployment ...
    2008-04-19Chan Stevens's FlisKits Rose-a-RocA8-3- Forgot to untape rotors, no deploy, ballistic landing. Repairable.
    2008-05-24 Moe Bertrand's FlisKits Rose-a-RocB6-2- PRM-16 B Helicopter Event. Motor blow-through on the pad...gained about 6 feet altitude with rotor ...
    2008-07-26Kenneth Jarosch's FlisKits Rose-a-RocA8-3- I launched the first flight on low power early at 9:30 to avoid winds and thermals. The copter ...
    2008-07-26Kenneth Jarosch's FlisKits Rose-a-RocA8-3- This is RocII. Lower Altitude. Slower Start. Better & faster Rotation. Wind blast fliped copter ...
    2008-07-31Chan Stevens's FlisKits Rose-a-RocB6-4- B-HD event, DQ/Unstable
    2008-08-09Kenneth Jarosch's FlisKits Rose-a-RocA8-3- This time I took the RocI (Almost stock) copter to the HPR launch to show the TRA-MN guys the ...
    2008-09-20Edward Chess's FlisKits - Rose-a-RocA8-3- First flight. Ejected motor. Took a second or two to orient and start rotation, but performed very ...
    2008-11-09Tim Dicke's FlisKits Rose-a-RocA8-3- First flight qualified for the A-Helicopter duration event. Rotation was very slow and so the ...
    2008-11-09Tim Dicke's FlisKits Rose-a-RocA8-3- Second flight went much better. Blades fully deployed and we had much better rotation. 30sec ...
    2009-05-23Edward Chess's FlisKits - Rose-a-RocA8-3- Very long recovery flight time. Just perfect rotor deploy, and started spinning fairly soon.
    2009-09-12Edward Chess's FlisKits - Rose-a-RocA8-3- Ejection delay timing good, but took a while for wings to deploy, losing altitude. Still, a crowd ...
    2009-11-07 Jim Bassham's FlisKits Rose-a-RocA8-3- First Flight. Hard to set up, but flew perfect. Really high for a A motor and such a draggy ...
    2009-11-14Jim Bassham's FlisKits Rose-a-RocA8-3- One blade hung up and it tumbled 50ft or so until it deployed, then it was ok.
    2009-11-22Jim Bassham's FlisKits Rose-a-RocA8-3- Everything worked perfectly and I got a 52sec flight. Wish the helecopter duration contest hadn't ...
    2009-12-05 Jim Bassham's FlisKits Rose-a-RocA8-3- Flew on a calm, cold day. Really nice, gentle flight. Got some great in-flight pictures. Real ...
    2010-01-02Jim Bassham's FlisKits Rose-a-RocA8-3- Excellent Flight on a calm day. Flew right back to me and I caught it.
    2010-04-03Jim Bassham's FlisKits Rose-a-RocA8-3- Snow Ranch Contest - slight hang on deployment, but made slightly over 50 seconds.
    2010-04-03Jim Bassham's FlisKits Rose-a-RocA8-3- Second contest flight - a kid almost caught it which would have disqualified me. Combined flights ...
    2010-05-15Edward Chess's FlisKits - Rose-a-RocA8-3- Another great flight with reasonably quick deployment of rotor blades. Very high rotor speed and ...
    2010-08-05 Jim Bassham's FlisKits Rose-a-RocD10-5- NARAM 52 D-helecopter Duration - Amazing flight of 6 minutes 45 seconds for NAR record. Found ...
    2010-08-05Jim Bassham's FlisKits Rose-a-RocD10-5- Second contest flight. Drifted away and timers lost track after 4 minutes 30 seconds. I lost sight ...
    2012-07-07Edward Chess's FlisKits - Rose-a-RocA8-3- Good boost, string burnt, but stayed wrapped around blades. Lawn dart. Will need to repairs before ...
    2013-09-22Jeffrey Gortatowsky's Rose-A-RocA8-3- Motor kicked. Burn string burned. Blades did not unfold. Nose cone split on impact. Fixable.
    2013-11-02Jeffrey Gortatowsky's Rose-A-Roc1/2A6-2- It worked! Pretty slow to spin up. And it wobbled a lot as it spun. I have increased the dihedral. ...
    2015-08-22 Richard Holmes's Rose-a-RocA8-3- Next, the FlisKits Rose-a-Roc on an A8-3. First flight, for the helicopter duration contest. 34.88 ...
    2015-08-22Richard Holmes's Rose-a-RocA8-3- Did I say “the successful flight was achievement enough”? Poppycock. I flew the ...
    2017-08-12Edward Chess's FlisKits - Rose-a-RocA8-3- Good boost, did not spin well--needs rotor alignment.


    J.F. (September 23, 2007)

    Thank you Chan for this review, for building the beta and for all of your feedback :) Many of the points you make will be addressed in the final product. After the Nanite MMX RG, the Rose-a-Roc is next. As you pointed out, many of the improvements to the design will be offered as hints and tips throughout the build. The intent here is to provide a faithful reproduction of the actual Rose-a-Roc letting the modeler consider changes as they build. As for the MonoKote for the blade hinges, after a conversation with Art Rose I am looking for a source for mylar tape. Keep watch for an announcement before years end! jim

    K.B.J. (September 5, 2008)

    After losing 2 Rota-Rocs in the 90's to wind and thermals on B & C motors, I couldn't wait to try this Folded Rotor Copter. It's light wt. 0.70 oz. and small frontal profile were bound to be a real performer. I also built a second copter with balanced rotors, stop blocks and "S" hooks for rubber removal and replacement. Several flights so far on A8-3's were extremely long flights with a fear of losing them again. Lots of fun

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