The original stock 4D tail pieces would flutter at high speed (over 2/3 throtle with a 4" pitch prop). We felt most of our customers would want a plane optimized for 3D flying, so we never addressed the high speed envelope -- preferring to save weight and ultimate servo authority for 3D controls. However, several customers have expressed desire for a wider speed envelope, and one in particular came up with a simple and effective solution (see below).

Version 2.5 and newer kits have parts and instructions for BOTH 3D AND high speed flight.

To minimize flutter in general on the 4D, we recommend addressing 2 main areas:

1. Linkage Geometry: If you want to fly fast AND still be 3D capable, you need big control horns and servo arms. You also want to have simple and straight runs for your push rods.
   The deluxe kits come with the large Dubro "T" style control horns, and instructions show exactly which hole to use for clevis connection. Not all brands of servos come with large (1" or greater) servo arms, and you may not get desired deflection on elevator throw due to the standard servo arm not being long enough. Dubro makes large grey (or white, depending on brand) "super strength" servo arms to fit all brands of servos which will give the needed travel to get 50 degrees of elevator travel up and down. Having the bigger dimension on both the servo end AND the control surface end is the key to minimizing flutter while keeping the big throws for good 3D.
   
   
2. Counterbalances: Add small weights which protrude from the LE of the tail surfaces and balance the mass of the all moving tail piece on the axle. Full scale planes use this technique.

Here's the short answer: near sea level (below 3000 feet) -- Yes.

The 4 strokes tend to have more instant pulling power at half throttle, which is where you want to hover the plane. The instant thrust gets you out of trouble better than with 2 strokes. If money is absolutely no object, and you're in the market for an engine for the 4D, then I recommend a 4 stroke. Keep in mind, you're going to be crashing frequently (that's the whole point in learning with this plane), so if the idea of burying a pretty 4 stroke into the mud regularly isn't palatable to you, maybe consider a 2 stroke until you get past the initial stages. The good news with 4 strokes, is that many of them have carburetors that do not face forward, so their carb intakes stay free of dirt in crashes.

The other reason I favor 4 strokes is the sound, or lack thereof. As you get comfortable with torque roll practice, you find you'll be hovering rather close to yourself, and the constant whine of a 2 stroke gets a bit annoying compared with a 4 stroke sound.

Saito makes a .72 and .82 which are excellent choices. A YS 63 is also a good choice.

For two stroke engines, a very good durable prop is the Master Airscrew 11x4. It will stay together in full throttle dirt-nap crashes when all others will not. We provide Master Airscrew 11x4 props in our deluxe kits. APC props of similar size will provide more thrust, but are heavier and not as durable.

For 4 stroke engines, the Master Airscrew 13x5 K series or 13x6 Scimitar prop are very durable and give good thrust. My favorite prop for the Saito .72 is the Zinger 14x4 as it is lightweight, and gives near instant spool up for quicker acceleration out of tight jams. For ultimate thrust, the APC 14x4W is king. The YS 63 prefers the 13x5, and will not swing the 14x4. The Saitos also respond VERY well to the 13x6 Scimitar prop. The extra pitch gives a bit more air over the tail for tumbles, with very little sacrifice in instant thrust.

3M77 is a spray glue that glues many of the pieces in the foam wing construction, and provides the all important bond between the covering and foam wing. There is no acceptible substitute for 3M77.

Polyurethane glue is a lot lighter than most other glues, and it gives a strong bond. It expands to fill all little crevices in the foam when sprayed with water. It takes 4 hours for the poly U glue to cure. It's better in EVERY respect from durability, ease of use, strength and longevity. It carves and sands easily when cured, is slightly flexible, and can be chipped off radio components and other areas if it foams up too much. A true dream glue. Elmers "Ultimate" glue (formerly called "Pro Bond") is excellent, as is "Gorilla Glue."

Goop is necessary to bond several of the internal plastic braces and engine mount plate to the foam, and each other. You can use any of the varieties (marine, carpenters, household, auto, etc.), and you don't need much, but there isn't any good substitute EXCEPT these:

• Shoe Goo
• PFM
• Zap-A-Dap-A-Goo

The CG should be 5 inches from the wing leading edge. The 5" point will allow good harriers and an excellent entry point to practice hovering and starting to learn 3D. You can go back further as far as you like, but realize it will porpoise very strongly once you get into "normal" flying mode. Once you get used to this, you'll find you can go REALLY far back, however, you'll always be "stuck" in a harrier and the plane will never like to fly on the wing.

Keep in mind, NO balance point will actually make torque rolls easy. It still takes a lot of practice to learn that rudder, and it will never be as easy as just sticking a pole into the ground and watching it stand as though it was stable that way. A rear CG gives you more authority to correct deviations as the plane wants to fall out of a hover, but it will never be easy. I find the 5" mark is a good spot for everything, as the plane will tend to fly very equally inverted as well as upright, and is not a handful. Back further than this and EVERY landing you shoot will be a mandatory harrier landing, which takes throttle management and varying elevator compensation throughout the flare -- not an easy way to learn.

The best combo for learning 3D is a 4D and a flight sim. Burn as much fuel as you can, and fly the sim when it rains. If it snows, get some skis and get outside! There is no substitute for practice. You've heard it before, and it's true. It's also true I broke about 100 props to learn to torque roll. I'm not proud of that fact, but I AM proud that our 4D design took it all, and asked for more!

I was thinking of getting a video section on the web site for learning to practice basic 3D moves, with video showing stick movements and corresponding plane motion. The problem is that it really doesn't take a lot of stick deflection to make the plane perform many of the 3D maneuvers UNTIL you get into trouble, then you jerk the sticks around. If you watch someone's thumbs while doing a harrier or a torque roll, only very small control inputs are needed unless radical direction changes are demanded. The large control throws allow this.

Basically, I can advise you to first master the harrier. A Harrier is when the plane pitches up around 45 degrees, and stops flying on the wing-- in fact, the wing will just be dragged around, and really doesn't provide lift. Learn to balance the throttle and elevator. Steer it wherever you like in all directions using the rudder, with some aileron input to keep the wings level. You don't need to mix any spoilers to do it, although you can if you wish. If you notice ANY wing rocking at all, make sure your ailerons are not pointing down (like flaps) when your aileron trim is level as it should be rock steady in the harrier. If you want to get fancy, you can progress to inverted harrier (rudder action is reversed inverted, just like the elevator).

Unfortunately, the Great Planes G2 Realflight Sim is not much help in learning harriers, because all of the stock planes will "snap" out of a harrier attempt, and without major modifications, cannot be made to stop this. I have seen some highly modified G2 simulation planes harrier, but they usually do other things "strangely" and act like they are feather light, or flying under water. The planes just won't "mush" around like a good 3D plane will in real life. Realflight G3 has fixed this problem, and harriers are now possible, but they are still a bit more difficult to perform than on other sims (which is both good and bad for training). The new XTR sim is much better for harriers, as is the Aerofly Pro.

In the XTR sim the stock Katana is a VERY good all around simulation. The stock Katana will harrier easily, and does all stunts well except knife edge flight.

Waterfalls are easier to learn. Go to a comfortable height, enter a hover(ing) attitude, then give full power with some right rudder and full down elevator. If you have enough power and down throw (50 degrees is good), it will flip right over. You can either let it keep flipping like this, or catch it for a single waterfall flip. Experiment with differing amounts of rudder throw and practice high at first. If you try this enough, you will probably see a waterfall end up doing a knife edge spin (falling sideways, spinning around the wingtips and descending very fast), which also looks cool.

The only (stock) Realflight plane I've found which performs waterfalls on G2 well is the Sukhoi found on Add Ons #3. The XTR Katana will easily waterfall, and he big Extra 300 for the Aerofly Pro will waterfall very easily (maybe TOO easily). The new Realflight G3 has several 3D capable planes, and all waterfall very well.

Flat spins can be tricky to sustain with a plane designed for 3D. Spin entry is easy, by applying full left or right rudder, some aileron, and up elevator to initiate a stall and spin. Then, you need to finesse the ailerons to flatten the spin -- with opposite aileron, and adjust ALL the controls to keep the spin going, and the wings flat. Non-3D planes often do flat spins easier, as you can just jam the sticks in the corners and hold them there, but 3D planes with big control surfaces and control throws need a lot of finessing. You can do rising flat spins, inverted or upright with practice. It's pretty mesmerizing to do flat spins on a calm day a few feet off the deck.

I've found that most 3D capable planes flat spin easily on G2 and G3, Aerofly Pro and XTR sims, but if you want to keep the spin from falling, you may need more power on the G2 planes. The stock XTR Katana is excellent right out of the box.

Rolling Harriers are a lot like 4 point rolls, or slow rolls, with the controls blending into one another. The difference here, is you need to have lots of throw. If your thumbs "know how" to do a 4 point roll, you can work them into a roller, and they often "remember" how to do a roller to the left or right after a lot of practice without you thinking about it. Just be careful you don't rely on the timing of the motions-- you need to synchronize what you see to what each thumb does. The sequence of rocking your thumbs back and forth, up and down will always be the same, given your roll direction remains the same. You always need to give top rudder, and elevator to keep the nose pointed up to vector the thrust, and keep the ailerons deflected to keep the plane rolling as it slowly moves forward. You'll often hear pilots "pulse" the throttle during rollers, as it's a bit easier to combine throttle to be simultaneous with the rudder actions to better modulate the thrust needed for horizontal flight trajectory. All controls must be finessed to hold constant altitude, and once you master that, you can work on steering it around in circles or whatever other patterns you like (even loops!) Be sure to practice rollers rolling both left and right, so your thumbs won't get locked into one direction only.

I found the Edge 540 found on RealFlight Add Ons #4 to be EXCELLENT for learning rollers. It may be even a little bit easier than the Aerofly Pro or XTR. You may find that the amount of control you need varies from real life with your 4D, because the 4D responds more quickly than the simulated big planes do, so you won't be banging the sticks to the edges like you'll need to do on the sim. I found the XTR Katana actually more difficult to perform rolling harriers.

Don't fear the wind! You'll sometimes hear that 3D pilots only like to go out on perfectly calm days to fly. Flying in still air is certainly a nice option, because you get to see EXACTLY what the results of your control actions are in practice. A 3D flyer being "afraid" of the wind it is quite unnecessary, considering the skills for mastering 3D are far in excess of what's needed to control a plane in VERY windy conditions.

On a calm day torque rolls and spins can be stationary in space will not drift with the wind like they do on windy days. However, windy days are actually very good for practiceing rolling harriers! With the 4D, you don't need to worry about crashing, so you can bring the plane down in front of yourself facing into the wind, and roll it to the right or left, angled upward, and give the correct rudder and elevator inputs as the plane rolls through knife edge, then inverted, then to knife and then upright and so on. I found my 3D roller skills increased the greatest after long practice sessions in wind. It gives you a "platform" to keep the plane at a comfortable distance and you don't fear so much if the plane starts to slide towards yourself like it might in still air doing torque rolls. Your recovery options are "safer" because the plane should always be pointed AWAY from you in this practice mode.

The wind will usually throw you some turbulence, so you'll find the plane "lunges" up or down, so you'll need to compensate with throttle AND varying degrees of elevator and rudder. It's good to be downwind of an open area devoid of tall structures (trees, houses, etc) so the air will be smooth and the turbulence will be less.

By far, the most difficult 3D move for most people is learning to torque roll. A torque roll is a special kind of hover, because the plane points straight up, and the torque of the engine will always want to rotate the plane to the left (like left aileron was given). It's the signature "holy grail" of all 3D moves, and even guys who do it well find they like to practice it, because it gets very addicting once one gets "over the hump". It's fun to do tail touches, and exhibit ultimate control in what looks to be the most impossible stunt of all time.

Learning the torque roll is just a lot of practice, and several bags of propellers for most people who fly the 4D. You need to train your left thumb to know which way to correct the plane no matter how you look at it. Your right thumb should already know what to do by now. I fly the sim a lot at night and in bad weather to augment my real life stick time. This could take several months. Your mileage may vary. Don't get discouraged! Your 4D will survive with minimal repairs.

A CG around 5.5" will help, and you can even go farther back than this, but keep in mind, it will NOT fly normally anymore on the wing, and will always want to harrier -- doing wierd things like ballooning on landing, and going out of elevator trim at different throttle settings. You should be able to handle this after a while, but a rear CG takes a lot of attention.

I found the G2 Edge 540 to be a good torque roll trainer. It's knife edge has a wiered "kink" in it, but it reacts nice and slowly, like a true simulated large plane should-- which makes it easier to learn how to use that rudder. The Edge flown on G3 is VASTLY improved, and a lot of fun to fly. I believe the only modifications I made were a slight increase in control throws, but you should adjust these to your liking anyway. Power and balance are fine in the stock configuration. It will torqe roll very easily on the G2 with one important caveat-- you cannot enter a TR from a harrier! (which is the normal "real life" approach. Thankfully, G3 fixes this problem). Consequently, on G2, you'll spend a LOT of time getting into a "tail slide entry" by going high nose up, and letting the plane slide down to lower altitude where you can see it, and finessing everything so it won't fall over and start a snap roll-- which cannot be recovered. The G3, XTR and Aerofly Pro sims do NOT have this problem.

The Realflight G2 and G3 sims have other attracitve features (flying online with friends for example) which the Aerofly and XTR do not have, but because of the "hyperactive snap roll" tendancy of most of the Realflight planes, you may find the other sims easier to deal with. However, if you DO master the G2 or G3 sims, you will have a VERY healthy respect for detecting and preventing an unintentional snap roll, which is an invaluable skill in real life. Many planes with high wing loadings are very touchy 3D performers, and knowing how far you can (and cannot) push them takes a lot of practice.

While pull pull is not mandatory, it is very beneficial on the 4D for these reasons:

1. The wing is inherently flexible. Our double tape hinge method combined with the constant tension of the pull pull lines preserves the integrity of the hinge -- despite repeated pounding and flexing of the wing, which will tend to detach or break hinges mounted in conventional ways. The pull pull lines stay tight because the tape hinge creases down into the hinge crevice, and there is some "springiness" while still allowing a very free hinge movement.
2. pull pull setups are always lighter than push rods.
3. A pull pull setup garuntees equal control accuracy for the forces generated on the very large ailerons acting both UP and DOWN. A single push rod acting a the top or bottom of the wing may tend to "kink" in compression, especially as the hinge wears on a conventional setup. You've probably experienced this with rudder controls -- they work well in tension, but you often get less accuracy in compression due to imprecise hinge location, and play in the connection points.
4. You don't need any clevises for the pull-pull setup we've devised. The method we show for threading the pull pull lines results in centering that is easily adjusted and then easily locked in place at initial installation, plus It stays tight for a very long time.
5. the hinge tape we supply with the deluxe kits is very fuelproof, and automatically seals the hinge gaps. Plus, it's easily removed if you make a mistake in the initial application. We give a full 25 foot roll, so you'll have extra should you wish to use it for repairs in other areas.

This is usually caused by the mounts "drooping" in storage -- especially in hot weather. The plastic is very tough and will not break, but it does tend to bend if stored improperly. The best way to store a 4D when not in use is just point it nose down on the floor so the tail points up. This keeps the weight of the plane pushing UP on the mounts, and also allows after run oil (you DO use after run oil, right?) to run into the front bearing.

Use only Ultracote! Monokote won't stick well to the foam, and is NOT as durable!

Be sure to watch the seams of your covering-- especially around the engine area. Clean it and make sure fuel can' t seep in. Fuel will soften the 3M77 glue and could cause problems later if you let it go too long without patching. I put some extra hinge tape under the engine mount beams to prevent the covering from chafing and tearing after lots of crashes.

Don't warp the wing (during covering) It's a good idea to apply the covering to the wing holding it tightly so you don't need to apply too much heat to get it attached. If you introduce a warp during this process, you can correct it by heating and twisting as necessary. Remove the heat and hold the twist while the covering cools. It shouldn't take to much tweaking to get a straight wing, and results will be obvious after you fly when your ailerons trim evenly together for "zero roll". Don't fly around with a warped wing! Take a minute to iron and twist it so it's straight. If it looks straight, it probably is!

Dark colors may tend to shrink a lot in the sun, so be careful when covering large areas. With attention, black, dark blue, purple and others will work fine, but you might find them lifting and getting "pruney" with temperature and climate swings of the seasons. A little ironing every few sessions is a good idea

Fluorescent colors are heavy, as they have a backing ply of white, so they're almost twice as thick as non-flourescent colors. The newer transparent colors are very light, but not as durable as opaque colors. Don't let this hamper your creativity, but you may like to keep it in mind.

Glue your wheel hubs together The Dave Brown wheels we supply in the deluxe kits are the lightest available, but the wheel hub is made in two pieces and can slowly separate over time -- especially if you do a lot of ground tricks. If they separate enough, you'll notice the wheel won't spin freely, and it could affect your ground steering if one or both wheels lock up. Take the hubs apart by gently pulling them, and apply CA, Goop or epoxy to the inside where they rub together. If you get any glue on the inside of the axle area, just clean it out with alcolhol, or re-drill after it cures. A #7 drill gives a perfect fit for the 3/36" wire gear we supply.

Be sure tail pieces don't rub on the axle bushings. Trim them to be sure they rotate freely. Check the elevator halves to make sure they're aligned together, and adjust the linkage by bending to keep it this way. Double check after crashing a few times on the tail. (no, this won't hurt it!) Also, squeeze the "Y" elevator push rods together before connecting to the control horns so it will keep the elevator halves together.

Don't over-engineer the tail linkages. They are slightly flexible on purpose, and will save your servos. If the tail is fluttering, you're flying too fast for your control geometry. Move the axles if necessary and add counterbalances as described above and/or bigger horns. If your tail pieces are getting worn and ragged, make new ones from scrap pieces of corplast.