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Post by burcham8 on Sept 20, 2008 21:35:52 GMT -5
Guys --
I had a lot of fun tonight tuning one of Henry Tomkiewicz's C-130s so that I might fly it. I got a lot of things right, I think. However, the a/c will not slow down on the ground; it wants to taxi at 60 mph+. The only way to stop it is to reverse props.
Any suggestions as to what section in the cfg I might tinker with next?
Marc
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Post by qxtoolman on Sept 20, 2008 23:40:30 GMT -5
Guys -- I had a lot of fun tonight tuning one of Henry Tomkiewicz's C-130s so that I might fly it. I got a lot of things right, I think. However, the a/c will not slow down on the ground; it wants to taxi at 60 mph+. The only way to stop it is to reverse props. Any suggestions as to what section in the cfg I might tinker with next? Marc If you know how to do a .air &.cfg swap, you might want to get Mike Stone's C-130 & use it. I think it works pretty good. As Tom says: "Hope this helps". |
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Post by railrunner130 on Sept 21, 2008 16:49:00 GMT -5
In the real-world, I'd say "downspeed the engines".  I had a hand in beta-testing the Sim-Shed C-130. The flight dynamics on it are the most accurate I've found. (I don't have any real stick time, but almost 3000 hours in the back, so I've got a feel for how the airplane behaves.) I'd like to see those flight dynamics brought to the HTAI airplanes. |
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Post by Tom/CalClassic on Sept 22, 2008 9:49:56 GMT -5
Hi,
Try moving your prop pitch lever to full coarse?
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Post by Dennis the menace on Sept 25, 2008 2:09:45 GMT -5
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Post by herkpilot on Sept 26, 2008 0:13:48 GMT -5
To add to the A-net explanation, beta range on the Allison is ground use only, flight use is strictly prohibited and would quite possibly ruin your day- permanently.
In the ground idle range (Beta), the power lever sets blade angle and fuel flow thru a mechanical linkage yielding a limited range of positive and negative (reverse) thrust. In the flight range the prop acts as a governor, maintaining a constant rpm while the power lever acts like a thermostat, varying the torque (power) available. Increase the powers and the blade takes a bigger bite, reduce and it unloads. As installed in the C-130 (at least all versions prior to the new J) the prop always runs at 100% (1041) rpm in flight. In the ground (Beta) range 94-105% is allowed. Below 94% theres a good chance the the 10th stage compressor bleed valves will open, and the engine will flame out. Above 105% the overspeed protection features of the propeller will activate, locking the pitch and turning it into a fixed pitch prop. There is also a low speed ground idle range that reduces RPM to about 67% with a limited amount of thrust available. In the Herk we often taxied with 2 in low speed and two in normal to ease the load on the brakes.
I'm pulling all these numbers from memory so they may not be exact, but I was tested on them several times a year for many years so they should be close. I have a pdf file of an Allison training guide for the 580 that I don't know how to attach, but I'd be happy to send you separately.
Hy
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Post by capflyer on Sept 26, 2008 23:12:56 GMT -5
You're as matched up as I can be.
One other thing, in LSGI (Low Speed Ground Idle) the generator is offline. Thus, on any aircraft equipped with Allisons, at least one engine must be in HSGI (High Speed Ground Idle) to provide generator power. Otherwise you have to use the battery or APU (if equipped) to provide electrical power.
Also, your power levers on the Allison do act like a thermostat, literally. Above 65% of their movement range, each "position" that can be detected by the servo on the engine which the cable is attached to commands a specific temperature, not a torque, RPM, or horsepower. This is unique to the Allison and basically makes it simpler to operate the aircraft since moving the throttle to the same position will always yield the same temperature no matter what the conditions, thus reducing the likelihood of exceeding the engine's one critical condition - temperature. There are other systems which ensure that you don't overspeed, overpower, or overtorque the engine, but there is no system which prevents overtemping the engine.
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Post by Dee the man on Sept 28, 2008 22:40:34 GMT -5
>>One other thing, in LSGI (Low Speed Ground Idle) the generator is offline. Thus, on any aircraft equipped with Allisons, at least one engine must be in HSGI (High Speed Ground Idle) to provide generator power. Otherwise you have to use the battery or APU (if equipped) to provide electrical power.<< CV580? You mean the AC generators are off-line in LSGI. Be careful to specify.  The 28-volt DC generators are on-line anytime the engines is running, regardless of whether it is up- or down-shifted. The engine driven AC generators are (monsters!) 210-volt 3-phase, primarily for the prop control. Frontier birds also used them to power the ground blower fan for Air Cond on the ground. All other AC voltage requirements (radios, engine instruments, etc) are provided by the 115-volt, single phase mechanical inverter down below. Dee |
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Post by Deleted on Sept 29, 2008 2:23:22 GMT -5
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Post by capflyer on Sept 29, 2008 8:29:48 GMT -5
CV580? You mean the AC generators are off-line in LSGI. Be careful to specify. Yes Dee, you're correct that the AC generators are offline in LSGI, but this is true for any 501-equipped aircraft. I've checked the C-130 and L-188 manuals (thanks to Snow Aviation) and both have the same note about not running all engines in LSGI for an extended period of time due to the risk of running down the batteries and over stressing the electrical system. |
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