E Mail: RWS123@msn.com AMA# 2099

by

Bob Sadler

Now that the temperatures have finally started to rise, and if you’re a fair weather flyer like myself, I hope you are starting to get in some flying time. I was out at our club field a few weeks ago and just as I opened the door to my truck and stepped out, the clouds opened up. I stood there and watched in amazement as to how fast some of our fellow club members can pack up their gear and clear out.

I spoke to the people again at the DuPage County Forest Preserve and inquired as to when we might expect delivery of the wood chips. They were very cordial but could not give me any kind of date for delivery. I also inquired as to the possibility of obtaining a few more picnic tables. They stated that the wood chips would be there as soon as possible, but don’t count on any tables. They will however "hold our request" for the tables. I’m not sure what they meant by "hold our request."

At our last meeting we had a discussion on the different possibilities of obtaining a barbecue grill to keep out at our field. I think our problem has been solved. Glenn Skanderup has graciously volunteered to build us one out of a 55 gallon drum and we can chain it down to one of the tables or trees. Thanks Glenn and sorry I had to put the arm on you!

If anyone needs a DuPage flying permit application, let me know, I have a stack of them. Please remember that I need some articles for the newsletter. Anyone who would like to read "The Ground Effect" this is the newsletter of the Michigan Whirlybird R/C Helicopter Club, I will have one at each meeting, just ask me for it.

Hope everyone can make the next meeting, it will be held at the club field (Weather permitting). Until then, take care.

Mark Potts

Minutes from 13 May 1997

.

• There were a lot of sellers, but not many buyers/kids.
• We are looking for sponsors to donate $100-$200 per year in cash or merchandise to our club in return for advertising in our newsletter and web page.
• Bob is looking for any kind of information to put into our newsletter.
• We need to find a way to have a BBQ grill at the field and are looking for ideas. Remember that we cannot have anything permanent at the field.
• We still have no wood chips at the field.
• We have scheduled BBQ's at the field for:

• Our October fest is scheduled for September 20th and 21st.
• We are going to assign committees to run the events, food, etc.
• We discussed our Web site and the Michigan Whirlybird newsletter.
• Pat Chow won the crash and smash award.

Santini Air had a Jet Ranger. What were the three colors in the paint

scheme?

Santini Air had a Jet Ranger painted like the American flag, red, white and blue.

Many modern helicopters have what look like very robust antennas that lean forward at approximately 45 degrees. They have one on top and one on the

bottom. What are they for?

by

Chopper

My Hawk came in a plain white box, serial # 0006. Taken out of context these two facts don’t amount to much. Both of these facts will have a greater significance further into our analysis. They are representative of Century’s intentions in marketing this kit.

What is the Hawk? In a nutshell it’s a 28-36 size helicopter aimed at the beginner but capable of expert maneuvers. More specifically, it is an Ex-Cell shrunken head, a concept copy tail, copy shuttle linkages, copy enforcer tail fins, and the frame of the Lion Helicat. More on this later.

As I opened the box I found the parts bagged according to modular subassemblies. Many shapes were recognizable as a large number of modules are previously assembled. These include fllybar carrier, rotor head, elevator lever, and main gear autorotation assembly.

I was intoxicated by the smell of plastic permeating the air as I threw the instruction manual aside and opened four subassemblies at once. Realizing my euphoria I sought ventilation. Regaining my senses I read through the instructions and I was very impressed. Century’s grammar has improved dramatically from their ads, which are infamous for their abrasive translations. (E.g., pre built blades)

The instructions are geared toward a beginner and even show a four channel/four servo set up that any plank pilot can afford to try. The figures included show assembly sequences and part differentiations clearly where as photos are sometimes ambiguous. The manual even showed where optional ball bearings could be used. There are 41 steps to assembly. Each step includes an exploded view drawing which will end any confusion on which parts are the correct ones. Even the preassembled part’s feature exploded drawings for future disassembly/reassembly. There are even indications of where to use thread lock (blue). I wish they would have included information on what needs to be greased, when and with what? (Oil? or Grease?) I learned this from experience but at the expense of worn out bearings and bushings over the years.

Century is trying to produce and market a helicopter that is both economical and beginner friendly. In order to make the helicopter economical,

costs must be trimmed to the bare minimum. Century achieves this in several different areas. The judicious use of bushings in the control system saves money over ball bearings. On the original prototype 24 ball bearings were used. This was pared down to 19 for the production model. Ball bearings are reserved for the tail drive shaft, tail rotor shaft, and main drive shafts.

Here’s where the box comes in, it’s a lot cheaper to go with a no-frills set up, at least at first. Every penny helps, and a generic box is preferable to cost cutting elsewhere.

Of the 14 ball joints on the head, eight are metal (four of the plastic ones are on the plastic swash plate) All of the plastic ones are positioned such that they allow mounting of a metal ball should the plastic one wear or shear.

Moving back to the tail, a traditional 2mm wire drive, which rides in a brass sleeve, provides tail power. A single aluminum boom brace ( a la Ex-Cell) with plastic ends ( a la Century ) holds the tail steady. Fins, horizontal fin mount, tail push rod guides and canopy are ABS, this stuff is cheap (quality) and therefore it is cheap (price).

The Hawk uses 3mm Phillips head screws for a large number of applications, however all nuts are nylon locknuts. The decals even forced me, a steadfast spray painter, to forego a custom job in favor of the well-balanced factory scheme. Besides, I can always peel them off later.

The tail is pure concept: blade holders, hub, shaft, pitch slider, and gearbox. A tried and true design, ‘enough said. The clutch, clutch bell, fan, and landing gear are also pilfered from the concept with the clutch assembly having its roots in the Heim mechanics of years(decades) ago.

The fin design is very similar to stock enforcer zr fins. The head is pure Ex-Cell design from the washout up, but slightly scaled down in size and with no thrust bearings. Another tried and true design.

The Hawk uses 3mm blade bolts and an 8 mm shaft. The linkages are traditional shuttle/GMP/Hirobo moving swashplate mechanics from the servos up to the swashplate. The servo layout is based on the shuttle as well. (But with less flex.)

The aileron levers, elevator lever, washout arms, bell mixers, collective yoke,

fly bar carrier, see saw, clutch bell, starter shaft, and tail bellcrank are all bushed. To operate slop free for a long time they need to be lubricated regularly. Don’t worry about the clutch bell being bushed, the only time there is dynamic friction is when the engine is at idle and the clutch is disengaged. Just keep the brass eyelet clutchbell bushings well lubricated and they will last longer than you might expect.

Now that we’ve seen where Century has cut corners and/or plagiarized, we can look at their more original features.

For beginners and airplane jocks the cone start is invaluable and self-explanatory. For helicopter pilots its durability remains to be seen. The die hard can install an aftermarket concept fan and use the Pegae wand.

The positioning of the engine allows easy access to not only the glow plug but to the carburetor as well. ( You are using after-run oil aren’t you?)

The Hawk includes auto rotation ability, which I feel is just as important for a beginner as an expert. A beginner finds himself/herself out of fuel, or with a bad mixture, causing the engine to quit. Without an auto clutch, blade speed is lost rapidly and even a hovering beginner can crash hard enough to cause damage. With the auto clutch, the heli floats down like a feather with plenty of head speed for a soft landing.

The fan design used in this kit (forward facing blades) develops its highest efficiency with moderate to low RPM. Exactly where a beginner running 15 % nitro, with a muffler, and hovering all over the place, is likely to run. If the Hawk is to be used with a high RPM engine, I would suggest a concept super fan, (rearward facing blades), which develops its highest efficiency at higher RPM than the stock unit. The shroud is molded into the mainframe and the cooling duct fully encloses the head of the engine for optimal cooling.

The gyro mount is under the main shaft which is great for beginners who are likely to be using electro mechanical gyro units.

The Hawk has a gear ratio of 10 to 1 and uses a two-stage drive train, which traditionally has been rumored to be more efficient than a single stage. Whether this is true is debatable, as only a hand full came to market. (Schluter’s Magic and Futura being two.)

With all this efficiency available, the Hawk makes use of it and stretches the

limits of a thirty size chopper with 550 mm blades and a 49.5" disk. Only the enforcer zr has a rotor disk this big OEM.

Tail blades are definitely K&S of Japan type, otherwise known as KSJ. Tail rotor diameter is big, 9.3". Only the Ex-Cell 30 (9.4") and the Ninja (9.37") have bigger tail rotors, and the Ex-Cell runs at a fraction of the speed of the Hawk’s. The tail speed is high at 1 to 5.25, which benefits the beginner likely to be running slower head speeds. Tail sensitivity will still be promising even at slow main blade speeds.

The main blades are from Aerotech, fully symmetrical laminated wood covered in heat shrink with a double cut sanded tip. (The tip is cut only twice to simulate/approximate a curved tip.) These are a cheaper version of the Erithacus sold by Century, and they only have two laminations, one hardwood, one balsa. Century’s Aerotech blades have several laminations of hardwood and softwood. My set had identical cgs but the weights were different by a few grams. I don’t know if this is intentional, (matched CGS), but blades with identical CGS can be balanced on a simple teeter balance, adding weight on the light blade’s cg. This simplifies things tremendously for the beginner, and makes things easier on Century in terms of blade matching. The instructions show a simple bolt balancer, which as long as the cgs match, will suffice for a beginner. The manual says the blades are already balanced but to check their balance after gluing the cuffs. Mine were to out of balance to fly without correction.

The kit includes an engine mount for a 28-38 size engine, but an optional 46 mount is available. This conversion is only recommended for intermediate to expert pilots because the power available can be dangerous in the wrong hands.

The tank included in the kit is a little on the small side, having been designed for beginners using 15 % through a muffler. Using a 46 would cut the flying time to less than 10 min. per tanks. The gyro mount is directly under the mainshaft, and the gyro can be moved to the front so a larger fuel tank can be fitted. The gyro mount under the main shaft is really only needed if using electromechanical gyros. Solid state piezos will work the same anywhere in the heli and is a better match for a 46 with its high torque. Mechanical gyros in the front of the heli can still detect the yaw rate, but it cannot eliminate the effect that lateral motion has on the mass of the rotating

flywheels. This inertia skews the yaw rate.

There were not parts missing, and the quality of all parts was superior. This is remarkable on an early sample, (remember serial # 0006?) and in many reviews the authors describe days, even weeks, agonizing over a few missing or inadequate parts. Missing parts are even more frustrating for impatient beginners. Century seems to have a good quality control program, based on this one kit.

As a testament to the Hawks simplicity is the fact that I had assembled the main airframe minus engine and radio in four hours. Radio set up took about the same. The radio set up instructions are very complete and insure proper set up if followed to the letter.

Century’s ads proclaim the Hawk’s weight at 6.2 lbs. What a pig! My Kit topped the scales at 5lb. 9 oz. which is lighter than all but two 30 size kits on the market. (Shuttle 5.17lbs.;Concept SRT 5.5 lbs.)

The Hawk is definately the least expensive chopper on the market, but it is a great value and the perfect place to start learning to fly. Replacement parts are very cheap compared to imports and this plays a big part, post crash affordability. Also you are assured parts availability since Cindy will stock the helicopter and parts can be readily obtained from Century through Als.Even if Century could not supply parts, suitable replacements can be found from either Hirobo, Kalt, Ex-Cell, or Kyosho for most assemblies, and aftermarket manufacturers for the rest. (KSJ, T&T, H&H, etc.)

Well now for the real part of the review: How does it fly? I had to wait several weeks for the sub-zero temperatures and snow to subside before I could guage the Hawks performance.

I installed an RCD 8 channel Dual Conversion receiver on ppm/fm. Five Futaba servos carry the load, and a Futaba 154 gyro holds the tail. A Sanyo 4 cell 1200mAh sub-c size pack powers the whole mess. Everything fits with plenty of room for more if you want to add a mixture servo or humongous battery pack for example.

Speaking of radios, if you are a beginner, I have only one word of advice, Stay away from channel 43. Mysterious interference arises to snatch models right out of the sky. If you already have channel 43, then get rid of it before it’s too late. Don’t make me say I told you so. Now

back to the Hawk.

I was able to get a pitch window of 21 degrees. This allowed a normal curve of -2 low, 5 mid, 9 high; a stunt curve of -9 low ,0 mid, 9 high; and an auto curve of -3 low, 5 mid, 11 high. Pretty standard curves for a thirty size machine.

Starting the Hawk was trouble free, but beginners be warned: the fuel tank is high and floods the engine easily. Route the fuel line higher than the carb venturi and this won’t happen.

A remote glow plug extension is required unless you want to remove the canopy each time you start it.

Spooling up the Hawk revealed that the blades were in track. I added some throttle and the Hawk was hovering with very little trim input. Head speed was running about 1450 which converts to 14,500 engine RPM. Right in the power band of the Supertiger G34H. The Hawk also seems happy at this RPM in forward flight and hover. (Tuned pipes and two speed set ups don’t go well together. The pipes are tuned for one RPM and at a lower RPM the tuned pipe smothers the engine.)

This is a smooth helicopter. Just like the JR Ergo, the Hawk is a little bigger than your average thirty size heli and it shows up very well in the sky. The shape of the canopy is distinctive and I did not suffer my usual disorientation problems in forward flight.

The Hawk will have no problems with aerobatics as there is plenty of cyclic authority. auto rotations will benefit from the large disk and light weight of the Hawk. I left off the fly bar weights and still had a stable hover in this gusty February weather. I was impressed with the way the Hawk flew, plenty of power, plenty of stability, yet full agility.

For $200 this thing is disposable. I will be ready for crash and smash. .....I just returned from the February meeting, after claiming crash and smash honors. My crash was due to and an engine problem when the heli was only 30 feet high in slow forward flight. The head speed was bled off steering and flaring so the arrival was a bit rough but I was right where I wanted to be, on the ground.

All of the upgrade parts that are commonly available for 30 choppers are available for the Hawk.

I just read James Wang’s review of the Hawk in Rotary and I am in disbelief of a few of his assertions. Apparently

he does not know which bearings come with the Hawk and demonstrated this possible confusion of the facts in his review. To use a larger tank James enlarged the hole in the side frames. A better solution is to seat the tank lengthwise. No need to butcher the side frames. I also don’t understand how James uses +10,0,-10 in stunt mode with an ordinary OS 32FSR on 15% with a muffler in a 6 and a half pound pig. I ran a supertiger g34H on a pipe with 30% and could only get 8 ½ use full degrees.

As there are no flying shots of James’‘ Hawk, I even wonder if he flew it. It looks awfully clean in the still photos. It is no wonder that Rotary’s integrity has been called into question. It seems as if each reviewer has some affiliation with the manufacturer. This is the clearest case of conflict of interest I have ever encountered. The appearance of impropriety is as damaging as the impropriety itself. Even in the total lack thereof. I wonder how much James paid for his Hawk? Yeah.......Right........paid? I wonder how much Century pays James for his consulting? Who is paying whom? And for what?

I didn’t get paid squat! The only time I’ve gotten something for free is in the pilots raffle, where everyone gets something. Does that mean I know what I’m talking about? No, and I’ll be the first one to admit it, but I do have opinions which I will voice shamelessly, and if I’m wrong, I hope you will correct me. (NO ......not in person.)

Thank You,

Chopper 97