Limited Altitude
Warm Up
May 2013
Mike Sidwell photos
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Limited Altitude Warm Up May 2013
Mike Sidwell photos |
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For power plant data click here
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| Dick Irwin | Chip with Rocketeer | John Trumbull with Trenton Terror |
| We flew a couple of warm-up rounds. Amazingly rusty. Greg got the closest to the target time -- 9 seconds. And nobody succeeded in the two 4-minute target attempts since everyone was down before 4 minutes. Then everyone made an unofficial (no timers) round and had some great flights! |
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RC-1 GOES FREE FLIGHT The RC-1 went free-flight after the 2.4 GHz antenna fell off the transmitter! Then it cruised over to the bee hives. The bee keeper saw it land there while he was working on the open hives. Before we could even get to the hives we met the bee keeper in his full protective 'space suit'. He was already on the road carrying the RC-1 back to us. He had no intention that any SAM 27 members got anywhere near his open hives. |
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Greg Huffman with his Dallaire and Loren Kramer with his brand new Folly
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| Aric's Viking is up. Dallaire next | Viking and Rocketeer ready to go. Then the Dallaire at the back | Dallaire up |
Motors in order of power
| PLANE | PILOT | Motor | Mfr | rpm/Volt | Prop | rpm | Lipo | Amps | Watts |
| 42" Kerswap | Loren Kramer | 10 | ST | 1000 | 9 x 6 | 7000 | 3 x 1300 | 11.5 | 80 |
| 48" Cleveland Viking | Aric Wilmunder | -- | GWS | 7000 | 3 x 850 | 10.5 | 105 | ||
| 48" Cleveland Viking | Loren Kramer | 2208-20 | AXI | -- | 8 x 6 | 8400 | 2 x 1300 | 19 | 135 |
| 72" Trenton Terror | John Trumbull | #10 | Eflite | -- | 10 x 7 APC | 8100 | 3 x 2200 | 28 | 280 |
| 72" Trenton Terror | Andrew Tickle | 3542 | Turnigy | 1000 | 12 x 6 eflite | 6100 | 3 x 2200 | 51 | 280 |
| Folly | Loren Kramer | 15 | Eflite | -- | 12 x 6 | 7000 | 3 x 2200 | 32 | 335 |
| Brooklyn Dodger | Jay Beasley | G15 | Turnigy | 950 | 10' x 8" | 8400 | 3 x 2200 | 35.4 | 345 |
| 68" RC-1 | Andrew Tickle | 2910 | Atlas | -- | 12 x 6 eflite | 6000 | 3 x 2200 | 50 | 500 |
| Rocketeer | Chip Buss | 4260 | Turnigy | 500 | 14 x 6 APC | 6 x 2200 | 34.6 | 692 | |
| 108" Dallaire | Greg Huffman | 4250 | Turnigy | 650 | 13 x 5 MAS | 8920 | 6 x 2200 | 70 | 1330 |
Motor Performance Data
In Limited Altitude events idea is to reach the required altitude (650 ft) easily within the time limit (30 sec). In other words the climb is intended to be a non issue.
The motor data shows that although the climbs are spectacular the power consumption is conservative. A mere 10A for the lightweight Viking, and around 30A for the rest.
For planes larger than 1/2 A size (48", 16 oz) the most used battery was the 3 x 2200 mAh Lipo. The typical current of around 30A is easily delivered by the inexpensive 3 x 2200 20C HK battery. Higher C versions would give more power because the voltage drop under load is less.
The heavy 3-cell RC-1 (12 oz/sq ft) needed 50A. It was in fact 50% above the minimum loading of 8 oz/sq ft for SAM electrics rules
The bigger (heavier planes used 6 cells instead of 3, but still consumed around 30A.
The Dallaire had a spectacular climb with power to
spare (almost 2 hp), drawing up to 70A on 6 cells. But Greg admits he has
never flown it at full throttle yet!
A good rule of thumb for reaching 650 ft in 30 sec is to use 100 Watts per pound.