Magnum Updates:
Right out of the box the Magnum is more than competitive in any stunt circle and some of the changes posted while adding a slight improvement, 90% of the stunt flyers couldn't tell the difference between a stock or improved Magnum. Having said that, there are a few things that can be done to improve it over the basic kit version. At the time the Magnum was designed it was at the forefront of design but like anything else, things change and move forward.
Wing: Not much to change here, the airfoil and the wing area has proven to be more than adequate if the weight of Magnum is held at 62 ounces or less. If you tend to build heavy then increase the thickness at the tip about 1/8".
Fuselage: Adding 1/2" balsa between the engine mounts is a good thing to do to increase the stiffness of the front end. Also adding .5 ounce carbon veil between the balsa fuselage sides and the plywood doublers also helps. On one version of the Magnum I built had a removable tank cover that bolted in place to hold the fuel tank in place and add additional stiffness to the front end. But there was no noticeable difference in stiffness and/or engine vibration.
Landing Gear: Fuse mounted gear is fine if that is what you want but the wing mounted gear is also more than adequate for grass fields. I fly off a grass airport runway and have never had a problem with the gear from normal landings. Now if you have a tendency drop that sucker in from 3 feet then all bets are off LOL.
Controls System: The latest versions of the Magnum kits were supplied with a 4" bellcrank and 1/8" music flap horns that were 1-1/4" tall from the center of the 1/8" wire to the center of the top bushing. The elevator control horn was 3/32" music wire and measured 1" from the bushing to the music wire. This was a big improvement over the 3" bellcrank and the 3/32" control horns. Adjustable ratio elevator horns are a good thing if you build the model under 58 ounces other wise, you will wind up at a 1 to 1 ratio again for maximum turn.
Flaps: The build up flaps work fine if they are covered with tissue and dope, but if you are going to use iron on film then make them from solid sheet or sheet the built up flaps with 1/32" balsa (best method).
Elevators: Just like the flaps, fine when covered with tissue and dope or sheeted with 1/32" balsa. Do not make the elevators from solid sheet!!! This will required additional weight in the nose for proper balance. Increasing the area of the stab & elevator from 20% to 25% is another slight improvement but one that I don't think is all that necessary. If you want to increase the area then the stab must become a built up unit (not made from foam). It has to be really light!!!!
Longer Tail Moment: The trend has been to make the tail moment longer and longer over the years and it has merit. But again, this requires the tail assemblies to be really light so dead weight is not added to balance the model.
Increased Side Area: Never was a problem with any of my models but if you want to increase the side area add a piece of 3/4" wide balsa between the fin and the rudder and switch the bottom fuselage block from 1/4" balsa to 1/2" balsa. I did this and could not tell any difference at all except it had more of a tendency to weather vain in the wind on the upwind side of the circle.
Engines: For the money the best engine that you can get for the Magnum is the St 51. That does not mean that other engines will not work as well or even better, but for $100.00 bucks it is really hard to beat. If you build light at 53 ounces then the St 46 is also a great combination (my personal favorite).
OK, time for my opinion on a few things. When one of the top fliers makes a change or implements a new design feature to his stunter, the rest of the stunt world follows like a herd of thundering turtles (LOL), mainly because that is what they perceive must be best. You have to remember that their models are very highly refined over a number of years and very specific to what they are trying to improve and/or achieve with their designs. In addition, these changes must fit in with their style of flying. Sure most of these changes do work but the rest of the design must be considered when making any change to the basic airframe. A good example of this is flying some of the classic models. With the modern control systems and power plants they can be made to fly superbly and at a very competitive level.
The secret to excelling in this sport has never changed, it requires a well built model that is properly aligned, built at a reasonable weight, a consistent running engine, constantly trimmed, hours of coaching, and practice and more practice. It doesn't matter who you are even if you have all the latest and trick gadgets on your world beater airplane, if you don't practice you don't win. So spend the time burning fuel and learning how to fly your model in all weather conditions.
