Control Tower - October 2002

This month, I have a new column announcement, news about a new contest, and a mini-review of the new Moby Dick giant (79.5” wing) “park flyer”.

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News and Announcements

This month, Bernard Cawley brings us a new column called Recurring Charge, which is about battery chargers and related technology. Bernard always provides detailed and very usable information in his columns, and the Recurring Charge is no exception. If you haven't had a chance to check it out, I highly recommend that you take a look.
This month, the E-Zone is kicking off a new contest. Shawn Palmer provides the details below.

The E Zone and Electric Jets Forum are holding a mini-jet building contest. The parameters of the power system are as follows. The jets can use any motor and fan combo bigger than the EDF 50, and smaller than the Speed 400 combos. This includes, but is not limited to Kp44's, and Speed 280 and Speed 300 brushed motor and fan combos. If there are enough brushless entries, they will be judged and awarded separately.
The contest is limited to non-pros. For the purposes of this contest, a "pro" is categorized as anyone who has built a plane that has been put into production or circulation through plans or through kits.
Contestants have until February 1, 2003 to complete and send in their entries to Shawn Palmer. Each contestant should provide pictures of the model and a mini-review that covers the basics of the construction, the materials and components used, and the flight tests. A flight video showing takeoff or launch, in-flight capabilities of the plane, and landing is strongly encouraged. RC Groups will host all the videos, so don't worry about bandwidth!
There is no limit on the size or weight of the planes. The planes may be single or multiple motor designs that have been built from drawings or plans designed by the modeler. Any materials may be used in construction, but if exotic materials/composites are used, the materials and methods must be thoroughly detailed enough to be reproducible by the readers.
The main voting criteria are flying capability, appearance, and ingenuity. The models should be capable of flight, and while pictures or video of the plane in flight might help in the judging, I will trust the modelers to give an accurate account of their flight tests.
The judges will be our fellow E-Zoners. Shortly after the deadline, the contestant's models and the mini-reviews will be unveiled in an E-Zone article. All registered E-Zone members who were registered before the contest was announced will have one vote. At the end of the voting cycle of 30 days, the winners will be announced.
Some prizes are already lined up from the nice folks at AERC, and there are more to come. If you are a site sponsor, and would like to donate prizes for this contest, let me know at sales(at)rcgroups.com. Now get to building, and have fun!
Shawn Palmer


October Articles (coming soon)

Conversion of rubber powered model planes to electric R/C

Gary Gullikson brings us an article that provides very nice details for the conversion of rubber powered model planes to electric R/C.


Chester and York Electric Fly-ins - Summer 2002

The Chester All Electric Fly-in usually takes place at the end of June or beginning of July at the picturesque Roodee racecourse, right in the centre of this historic town, located in a bend in the River Dee. The theme of the day is low-key fun flying, though a number of competitions are run, including scale, sports-aerobatic, vintage and the All-Up-Last-Down event.


Covering foam with Silkspan or fiberglass, and Minwax Polycrylic

If you are a foamie modeler or aspiring foamie modeler, this article provides good information on finishing foam airplanes with Silkspan or fiberglass, and Minwax Polycrylic.


Ford Tri-Motor Semi Scale ARF

Kavan has done a great job with the quality of materials and ease of construction with this Tri-Motor. It is a fine looking plane, and it draws a crowd whenever flown around a group of people. It has to be flown a bit faster than some park flyers, but it looks great in the air. If you want a nice flying multi-engine plane that looks as if it came right out of yesteryear, the Tri-Motor may be the plane for you.


F.F.X. P-40

Just as it was with the Seriously Fun Models, F.F.X. ME109, the P-40 is a relatively quick building, fairly accurate semi-scale, great flying plane. With its low cost and inexpensive gear, it would make an excellent Speed 400 club racer, especially when matched up against other F.F.X fighters.


Global Waco

The Waco is a bit heavy and a handful on the ground after conversion, but it is a very attractive plane, and the quality of the construction and finishing are very nice. It also includes a better than usual instruction manual, and is ridiculously easy to convert from glow to electric.


Grumbler

The Grumbler kit is a truly an ARF. The kit comes complete with a hardware pack, high quality trim sheets, and decals. The quality of the materials and workmanship is top notch, and the kit includes a very decent set of English instructions that include numerous small diagrams. Furthermore, while the Grumbler is mildly aerobatic with the stock power system, its greatest strength is that it flies well and lands at a nice walking pace using the ailerons as flaperons.


HOB AcroCub

House of Balsa has done an excellent job of improving upon a good thing. The semi-symmetrical airfoil and ailerons add a new dimension the Micro Cub's repertoire. This Cub uses the same sturdy, lightweight construction and well-matched power system that made for a great combo with the original House of Balsa Micro Cub. Like its sibling, this plane is easy to build, looks great, and has excellent flying characteristics, all which make for another winner.


HOB FW-190

With one of the new electric power systems available today, the House of Balsa FW190 is a sweet flying airplane. HOB kits in general are straight forward to build, easy on the pocketbook, look great in the air, and are great flyers, and the HOB FW190 is no exception.


Holiday 280

This model is well worth the investment and loads of fun. It builds quickly, but the most important thing is that it is a very agile and nice flying sport plane.


Kelly

It seems that beautiful sailplanes always fly better, and this review just confirms that statement. The Kelly is high quality through and through, goes together easily and quickly, and flies well both powered and gliding. Simply put, it is just one sharp little sailplane.


Lunch with Keith

Keith is back with a super-sized serving of advice. This month, he talks about prop and EDF noise, power loading, servos for small retracts, and more.


Park Central

This issue of Park Central showcases some nice old and new products, night flying with park flyers, another successful foam glider conversion, and details about a possible future project.


Recurring Charge

Battery chargers have come a long way in the past 20 years or so, and this column highlights those changes, as well as reviews a few of the current chargers on the market.


Southeast Electric Flight Festival - 2002

The Southeast Electric Flight Festival (SEFF) had its inaugural fly-in earlier this year just outside of Atlanta, Georgia. Despite a day or so of less than perfect weather, the fly-in went very well, and there was a very good turnout of modelers, sponsors, and spectators.


SR Batteries Bantam

In a nutshell, SR Batteries has hit another home run with the Bantam series. Each model is full of Larry's now familiar design innovations. They both fly great whether your setting is outdoors or indoor. The option of having one wing or two just makes it that much nicer. If having a limited space flyer that just "looks right", is easy to build, uses an inexpensive readily available power system, and happens to fly great appeals to you, then you should read this review.


WattAge F-86

The Wattage F-86 Sabre EDF is sport-scale model of the Korean War era jet fighter. Constructed of foam and plastic, it offers a short build time and entry-level EDF experience. Anyone with low wing flight experience should have no problem flying the Sabre.




...other stuff

The Moby Dick

Specifications
Ok, the name is a little silly, but this is a whale of a plane, so it works. The plane is advertised as a big park flyer that can be set up with a .46 glow engine or a Jeti 45/3 motor on fourteen cells. I don't know about the .46 glow engine, but let me spoil the ending of this mini-review by stating up-front that the Jeti 45/3 works very well in this plane.

My wife called to tell me that FedEx had delivered a couple large boxes. When I got home, the first thing I thought when I saw the boxes was that the word "large" was a bit of an understatement. I started to wonder if FedEx had mistakenly dropped a mini-fridge. After dinner (yep, I waited that long), I opened the box and removed the plane. Well, I tried to remove the plane. The box and plane were impressive, and the packing job from Hobby-Lobby was equally impressive. The plane was packed to the brim with bubble wrap. In fact, after I pulled the plane out, I had a hard time getting all the packing material back in the box! Don't misunderstand; the bubble wrap went back into the box without a problem. However, did I mention the foam peanuts? (I LOVE foam peanuts!) The kids loved them, the cat loved them, and I spent an hour getting them out of my living room. (Thanks a lot...) ;)

The elevator servo, rudder servo, and receiver are hidden under the black ABS seat, and the receiver pack sits on the cockpit floor directly in front of the seat. The flight battery packs fit nicely on the floor of the plane, just in front of the formers that separate the cockpit and nose. Since I don't intend to ever use this plane for aerobatics, the flight and receiver packs are held in place with Velcro. Before the main wing could be attached to the plane, the two panels of the wing connect to a middle piece using two rods and a rubber band. The rods of course provide strength and rigidity to the wing, and the rubber band is used to pull the panels together tightly. The rubber band connects to two eyehooks, one on the root of each wing panel. I have seen and used this technique before, and it works well enough. However, I noticed that after a few flights, the rubber bands and the wings were a little looser than they should have been. Therefore, I recommend doing two things. First, use two rubber bands to secure the wing. If one rubber band fails, the second one should hold the wing. Second, I recommend that both rubber bands be checked and replaced frequently. After the main wing has been assembled, it is connected to the fuselage with three large nylon bolts. The bolts, and flap and aileron wiring are then hidden beneath a black ABS cover. I use clear tape to hold the cover in place, but I am sure a more elegant solution could be used. In my case, I plan to try small rare earth magnets in the very near future.

Since the plane was a demo model for NEAT, it already had the motor, batteries, receiver, and servos installed, so it was essentially ready to fly. It has a flat-bottom, high-lift airfoil with flaps for slow speed landings, and uses five channels (flaps (2 servos), ailerons (2 servos), elevator, rudder, and throttle). I have done a few gas-to-electric conversions, and most have been fairly easy, but this plane looks to be the easiest conversion yet, since it has a massive, open area for batteries and gear. Personally, I cannot say how well or quickly it builds, since it came pre-built. Nevertheless, I can say that the Moby Dick appears well built and is easy to set up, even with the large multi-part wing and multiple servo connections. Within fifteen minutes of removing it from the box, I had the plane assembled.

Shortly after I had the plane assembled, I took it outside for a quick taxi test on the street. The plane has more then enough power and plenty of rudder control, but without a steerable tail wheel, the Moby Dick isn't the easiest plane to handle on the ground, especially with a slightly sloped landing zone or crosswind. Since the tail wheel is hinged, I tried several attempts to slave it to the rudder. The simplest and most effective method so far has been a 3/4 inch piece of fiber tape wrapped under the tail wheel wire and adhered to the rudder. The downsides of this set up are that it isn't the best-looking solution, and the tape has to be replaced every so often. As soon as I can, I will create a simple, better-looking adaptation to the existing tail wheel to make it steerable.

The first test flight went well enough, but I noticed a few things I wanted to change. Since the pushrod connections for both flaps were not on the same side of their respective servos, one servo had to be reversed or turned around, or one flap pushrod had to be connected to the opposing servo arm. I would have reverse just one servo, but my radio doesn't support that feature. Both low-tech solutions, turning around one servo and cross connecting the servo arm, would have resulted in a difference in geometry for the two flaps, which would have caused the flaps to deploy a-symmetrically. This is exactly what I noticed on the first flight. The Moby Dick flew well enough, but when the flaps were deployed, the plane had a tendency to roll to the one side. To resolve this, I bought a product from MPI called the "Miracle Y". The "Miracle Y" is a reversing Y-Adapter designed for giant scale, glider, pattern, or sport planes with split-elevators, split-flaps, etc. The Y-Adapter reverses one servo and lets the other servo operate as normal. The "Miracle Y" worked like a charm, and the added weight of the unit is negligible on a plane as large as the Moby Dick. In the picture of the servos and gear above, the "Miracle Y" is sitting on the floor of the plane between the two servos. I have used the flaps several times. Since they provide extra lift to a wing that already produces a lot of lift, I found it almost easier to land the Moby Dick without the flaps deployed, as the plane sinks better on the landing approach and bounces less once it's on the ground. However, I will be using them more so that I can determine exactly how much flaps I can use and when I should use them.
Another thing that I noticed during the first flight was that the rudder and elevator seemed to flex and move when the wind picked up or when full power was used. I checked both control surfaces when got home and immediately noticed the problem. The wires that Bohemia models had used on the plane were far too small for the pushrod tubes, and the control surfaces flexed 1/2 inch or more with mild pressure. The wires were even thinner than I would personally use on a Speed 400 plane. Since the pushrod tubes were large enough to handle larger wires, I went to a local hobby shop and purchased six pieces of wire, three pairs of increasingly larger sizes. The sizes at the store weren't well marked, but I believe that I settled on 1/16x36 wires. (They may be 3/64x36.) Anyway, the new wire fit nearly perfectly, but the action wasn't very smooth. After a few drops of "3 in 1" oil, the wires were moving very smoothly, and the control surfaces were rock solid, even with pressure. With control surfaces as large as those found on the Moby Dick, positive control is an absolute must. (The rudder and elevator are 1/3 to nearly 1/2 the total stabilizer surface area.)
I would like to mention one more note about the control surfaces before I move on. It is very important that the throws on the elevator and rudder are set to the limits indicated in the instructions. I don't always worry about such things. I just make sure that I don't push the sticks too far. However, on my third flight, just for kicks, I pushed the rudder full to one side. (At full throw, the rudder nearly touches the elevator). The plane rolled nearly 90 degrees, which took me by surprise. I expected yaw and some role, but it happened much quicker than I expected.) However, since the plane has such positive aileron control, and since the plane was "two-mistakes" high, I was able to correct immediately without incident. Since then, I have dialed the rudder down to the recommended throws. I have no doubts that this plane could be flown with just three channels. I just wonder why anyone would do such a thing. (tongue in check)

The second and subsequent flights have gone much better, and now, I can almost land the Moby Dick at walking speed. It takes off and lands easily on grass or paved runways, especially with its large, four inch main wheels. It flies like a giant park flyer, and can float along very slowly. Additionally, with the Jeti 45/3 motor, it has the power to climb very quickly. Under full power at altitude, the Jeti can pull the Moby Dick around with an authority that belies the Moby Dick's very light wing loading. I cannot say how fast it can fly with full power for several reasons. The first is that I am not used to flying such a large plane yet, so I cannot judge with any accuracy how fast it is flying. Second, even though I have pushed the throttle to full a few times, quite frankly I have been a little too nervous to "wring it out" for the fear of ripping off those large, high lift wings. Besides, this plane just doesn't look right zooming around the sky at full speed. The Moby Dick is very easy to fly and very stable in the air. It can fly with as little as nearly one-quarter throttle and coasts along quite nicely under half-throttle. So far, using mixed throttle, it has had eight to ten minute flights, and still had 400 to 600 mAh left on the fourteen 2400-mAh cells (two seven-cell packs). Someday soon, I will put the Moby Dick up for a duration flight. I think that it could fly for fifteen minutes or more with throttle control.

I only have a half-dozen or so flights with the Moby Dick so far, but I can definitively say it is an absolute blast to fly. Additionally, it looks impressive on the ground and marvelous in the air. It can slow down to a crawl and float around close in, or it can lift its tail in a split second on takeoff, climb quickly to a fairly high altitude, and cruise around at a pretty good clip. Even though it has power to spare, I don't see it as an aerobatic demon. In my opinion, that just isn't the purpose of this plane. The Moby Dick seems to be most at home when flown like a giant park flyer. With 2400-mAh cells, it has a very good flight time, and I imagine that with the new 3000-mAh NiMH or higher capacity cells, its flight times could easily be extended to twenty minutes or longer. While the Moby Dick is quite large, it is relatively easy to set up for flight and flies very nicely. If you put this all together, the Moby Dick is an excellent large plane that is very fun to fly as well.

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