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MODEL The latest Ramrod derivative, this one is an "E-Rod" -- Not much Ramrod left besides the pylon outline and the stab planform -- a 1/2A sized job was featured in the NFFS Digest and was scaled up 22 1/2% for the "390". It's original weight was 15.3 ounces and the first flight tests indicated great performance! Besides the 260 and this 390, the E-Rod is flying in 220, 450, 600, and 780 inch (approximate) sizes. A 1025 has been started. MOTOR One of the 3 best I have found is the Jameco Electronics part# 237391CM. It weighs 3.9 ounces stripped, turns 18K rpm (no load), and is reported to put out 509 gm-cm of torque. Although rated at 13.5 volts, I run mine at about 10 to 12 Vdc i the 15K rpm area. Power consumption varies with voltage, but is 100+ watts on only about 9.5 volts. Perhaps best of all, this MOST expensive of my motors sells for only $6.00 per copy! BATTERY Lipos, although permitted, have so many donsides, Im sticking with Sanyo nicads. 500 ar's would be within the weight allowed, but would not provide the needed voltage for real performance. Twelve Sanyo 250's do the job QUITE well and are barely within the 125 gm (4.4 ounces) permitted. Under motor load the initial voltage is about 9.5. (I wonder what this great motor would do if one really applied some VOLTS to it???) PROP The 7 X 3 1/2 is not the one Cox used on their 15, but is manufactured by GWS. It is made for direct-drive motors and has a hole smaller than the motor shaft; so the right size drill will pemit a push-on attachment -- use too big a drill and cyano will still hold it on. They also make an 8 X 4, but it lugs the motor, which then makes heat (wasted). TIMERS A Texas Micro-1 actuates an E-61 microswitch with a length of (super-strong) carpet thread, held with real thick cyano. The wire coming out of the top is used to pull an auto-rudder, needed for glide-circle (R-R pattern). DT is by a button (viscous) timer. |
SOURCES Model: NFFS Digest, April 2006 issue, page 11 (also see page 8 for a way to eliminate the need for a motor timer on beginner models, to hold down costs). Motor: www.jameco.com/ Jameco electronics, 1355 Shoreway Rd, Belmont CA 94002, 800-831-4242 Battery: Any good supplier of Sanyo nicads Timers: Hank Nystrom's Texas Timers
Ron St. Jean
10 Watkins Way Yerington, NV 89447 USA 775-463-2751 Addendum: The E-Rod was flown in F1Q at the Labor Day weekend meet at Lost Hills. It demonstrated the potential I believed it had. It was joined by a 450 inch "big brother" that is the same model as described , except for size and weight. The first flight of the 390 was nearly 5 minutes on the 20 second motor run allowed!! But then disaster struck, and two crashes followed, one on each model -- not due to the ships' fault but because of my own limitations. Because of this, I don't think I placed, my score being 3 maxes + the 2 crashes. But to my knowledge no other F1Q model at Lost Hills climbed faster or had a better glide. |