pprussell

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I have been testing a Mini Pulse XT for the last month. As with most ARF's the kit is a starting point. First, most folks are not going to be happy with 450 power. I am on the second motor, and now power with a Rimfire 35-30-950, 3S 1800mah 25C battery and 30 amp ESC and pushing an 11-7 APC-e prop. This will get you overe 300 watts. To go to the larger engine was intermediate surgery. Basically, to get the CG right with the added nose weight, you need to add a tray extension so the battery slides all the way back over the wing. You do that with balsa sheeting under 3/8x1/2" side rails with some end rails, allowing the battery to just slide on back over the wing with the end just showing by the magnet latch. Place the sheeting with the grain cross-wise, like the bottom of an old rowing skiff. That will stiffen up the wing saddle area which needs it badly in the stock design. Then you move the speed control into the battery compartment vacated, towards the front. Otherwise, if you put the battery in the tray area the factory provided, and use a 35mm engine, you are going to be way nose heavy. I can tell you, this design does not fly well at all unless you are on the 70mm CG or behind it, for more experienced pilots. To mount the bigger engine, punch out the factory blind nuts and laminate some aircraft plywood over the front of the motor box, but first add new 4-40 blind nuts to the new plywood to handle the new motor mount template. You need to cut an airflow hole in it with a dremel. And make sure to drill out behind the new blind nuts so the 4-40 bolts don't bottom out on the old firewall.
The next issue is the prop. Unless you go to a higher K motor, and run a 4S, and use a 9" prop, you will need to do something about the landing gear. That means anyone flying 3S is going to have an issue with motors with 1100K or below, or so, as you cannot swing enough prop. The stock gear is not up to rough field use, it is stiff and it does not provide the clearance needed to run an 11" prop which you will need to do with the larger motors with 3S power. Otherwise, you will not pull the watts with 10" props, which bottom out on rough fields anyway, and defeat the use of the larger motor. My solution was to get two cylindrical spacers that are plastic and black and about 1/2" wide and 5/8 high. These were used for flat screen TV installation. But a trip to the local hardware store will find nylon equivalents. Get some longer 4-40 bolts for the undercarriage and bolt the gear on with the spacers between the metal gear and the fuselage. Now you can swing the 11-7 and 11-8 props and make the 3S setup pay off in performance. As for the wheels, tossed those and got some good foam 2" wheels and cut out the fairings with the dremel.
Now, you will notice the stock linkages are going to let the control surfaces flutter. Not such an issue with the 450, but if you get a 35mm power system setup right, as described partially above, that flutter is the kiss of death. So ditch the linkages but keep the control horns. get the nylon, snapon ball links that Dubro distributes. These are used with new .047 control rods, and you solder on the ends with the socket and then bolt the ball part to the stock control horn. All the flutter is now gone.
Once you get to this stage, you can actually put the plane through its paces, and you will notice it is a forgiving flyer and does not want to snap out of high G banked turns and has gentle stall characteristics. If you keep the CG far enough back, you can use the elevator to flare in the landings nice, but you have to descend with some power on, as she is not a glider with the larger engine setup. If you are going to fly at these higher speeds, program some exponential into all the control surfaces. Maybe 35%. Now for the visibility. Wait till you line up those blue leading edges with some dark green trees in the background and watch her disappear before your eyes. So run strips of a high vis orange-red trim sheet along the leading edges and down the top of each side of the fuselage along the cabane. Now you can see is when it is moving faster with the larger motor. I am now to the point in the setup where we can begin to fine tune the mixes to get rid of the slight adverse yaw and a few other little details and plan to do that in the next week or so. My plane now looks fantastic, with the added high-vis trim, and is drawing a lot of favorable comments at the field. And it will pass most other stuff in the air on a typical day like it is standing still. I am toying with the idea of even more power, going to a 4S, to see if we can get into the 75MPH plus area, but want to fine tune things first.