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flyboy1950 -> RE: Hangar 9 150 Size P-51 (10/23/2003 2:50:06 PM)
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Yo Rocky! I looked at a lot of options regarding the gear and kind of feel that pressure tanks and pumping before every flight is a pain so I though trying to make the stock mechanism work was worth a try. I had heard all the complaints about the stock gear being too flexible and frankly, as you can see, I'm a scale nut and would not be happy with the look of the stock wire gear. The Robart 662 Offset Struts needed a lot of modification to make them fit the stock wheelwells. I did not want to mess with the nice finished look from Hanger 9. The 662's come 9" long from the factory and needed to be cut down to 6" (plus the wire that extends into the mechanism). Essentially, I had to take the struts apart, remove the piston and spring, shorten the strut to 6". I then discovered that I had to shorten the strut and the spring by 1/2". The struts come with steel inserts that had to be drilled out to fit the factory wires (I think 12mm?) and then the steel inserts are soldered into the tubes with a torch. You can do this without damaging the paint at the top of the strut but afterall, it's a warbird. The gear would not be spic and span on a real mustang. You can repaint. I also opened up a small section of the sheeting of the wing to reinforce the factory gear mounts. I did this for two reasons. 1. I generally feel that ARF's are not built strong enough in that area and reather that ficx the damage later, I beefed it up now. and 2. The original gear mount rails need to be shaved to allow the wheels to sink deeper into the wells for the offset struts. I left the factory rails in place and made 1" hardwood blocks that fit snuggly under each factory rail and epoxied in place. Take a look at Post #214 above and you can see a picture of the wing before I closed it back up. The result was a very strong mount for the gear. (I have 1 1/4 " screws attaching the gear to the wing!). I not only shaved the the side of the rails closest to the wells but I also shaved the front rail so that the gear would be a bit more forward when extended to minimize the nose over effect of the Mustang. I used Hitec HS-75 Retract servos. I used heavy duty servo arms and upgraded the hardware at the servo end to heavy duty with permanent steel
washes to hold them to the servo. I tried eliminating the hardware at the servo end and tried z bends. Forget it. You really need the ability to be able to adjust at the servo end. Adjustment ie critical. There is an adjustment screw on the gear mechanism to limit side to side wobble. Don't try to be too tight or the servo will struggle to release the lock in the down position. So I'm all lubicated and the gear seems to be working fine in the shop. P.S. The gear is on a seperate battery pak isolated from the receiver battery. If the gear gets locked in a partial up-down position, those 110 OZ servos can suck the juice out of a battery a hurry. This insures that I don't lose the model if the gear becomes an issue. Wow ... aren't you sorry you asked? Thanks, Flyboy1950
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