Geoff_H

if you run a 3-phase motor faster than it's maximum frequency i.e. 3000rpm or 1500rpm depending on the number of Poles you will generate electricity back into the mains. All you have to do in this case is have a variable speed controller for the power going to the motor and you can recharge a battery and use it as a brake

Actually there is no need to reverse polarity! If you load up the propeller and electronically change the frequency to be smaller than the frequency of the motor you will generate power in a multiphase motor. But I expect that there will be an increase in the weight of the electronic control.

I expect that the current would double when the prop would go in reverse. Possible large current carrying cables and extra weight

The pills didn't work for me. For me it was surgery or destroyed kidney. It was probably genetic, an ancestor of mine's birth certificate says that he died of an enlarged prostate, I always thought that it was cancer but maybe not. I have been told by a doctor that every male has. prostate cancer at 100, I believe that 85 is very true. Apparently prostate growth uses testosterone, they tell that control of prostate cancer is by the female birth control pills.

There are a few side effects of the operation. Dignity prevents me from mentioning them. I post this article in an effort to spread more information about the prostate. The medical professionals really were unable to diagnose a threat to my life. I got it fixed because of a throw away comment from a nurse. Your prostate needs to be monitored, not all problems are cancer.

I loved that Full SAR.

I am 72. I had trouble peeing for many years. I used to carry a bottle, I would pee in the bottle and release it to the atmosphere. Learning to discharge it without blowback into the cabin was required. Luckily most of my flying was alone. However what I wanted to chat about was the fact that my trouble with urine storage was not cancer but an extremely large prostate. For a long time I just put up with peeing a small amount often. Then a throw away line from a nurse doing an ultrasound on my abdomen asked if I had had the operation yet. I replied no she replied mine was enormous ( later I have been told that it was the biggest ever seen by the ultrasound practice). In the meantime I was having pain in my lower abdomen, situps and burpies gave great pain. I had a continual pain in my abdomen. My GP had sent me to hospital with suspected appendix problem. The hospital could not find anything. However I had the TURPS operation, they bore out the transition stage of the prostate. The problem of why a large prostate can kill you is that not being able to drain your bladder, the problem pain that I had, can destroy your kidneys. At my age a transplant I'd improbable so I would have died, as did an ancestor of mine. Now can go for around 8 hours without a pee! No problem and more ?. The moral of the story, get a fix for your prostate. Best thing I ever did. I can now do burpies!?

I used to love navigation and Full SAR. Shame it all went with GPS. However for those outback Navs GPS is so much easier. I became a magenta line jockey ?

I used to like the ADF to get the cricket when crossing the nulabor ? Shame that they closed them down, well maybe not. I used to hate night flying on an ADF, VOR was much easier. Geoff

A GNS430 has a VOR tuner in it. Independent of the GPS section. I had a GNS 430 and it had a faulty tuner. I had to upgrade to WAAS to get it fixed. Cost me a fortune. Geoff

Some 20 years ago I had an experience with "shotgun Sally" at Bankstown. I can't remember why, but I was entering the area from.a non standard approach. Then decided to fly to the standard approach point and report on arrival to that point. Well I accidentally called over the transmission of another aircraft. I thought that the controller, shotgun Sally, was calling me, she talked so quickly all that I could understand was the ending of her transmission was "qubeck", I was flying an aircraft that had a call sign ending in"qubeck". Well that slowed her rapid aircraft handing right down, did she give me a dressing down over the air. I was ever so cautious at that point. She gave me instructions to fly for a centre runway landing. In the following short time she must have changed the instruction to the left runway. I was certainly not answering any call that I was not sure of, so I never sent a confirmation reply. As I was on final descent I noticed a twin lining up on centre, I was confused and reluctant to report it owing to my earlier dressing down. The I got a very distinct instruction " clear to land on Left". I reported that I was on centre and given immediate go round. Things went normally after that. Some ATC official called me on my way home and said that they would be reporting me! Well after I replied to CASA with a written report saying that Shotgun Sally was difficult to understand and what had happened I never heard another thing. Not even that the issue was resolved or dropped. I avoided Bankstown like the plague after that. Geoff

Words You Should Not Use copied from the latest Mooney magazine “For” and “To” sound exactly like “four” and “two”. Used in the right combination of numbers, these words can be confusing and lead to miscommunication. Here’s an example: “Center, Mooney 257KW climbing to one thousand.” You can see how this can be miscommunicated as 21,000 feet. How about Mooney 257KW descending for 5000 (45,000 feet?). Instead, try to keep it simple, concise and understandable. “Denver Center, Mooney 257KW, four thousand two hundred, climbing one zero thousand."

Parachute canopy that is.

How does the manufacturer ensure the 20deg nose down. Are they 2 connections to the canopy or 3?

Does anyone have a parachute installation on the aircraft? If so what is its deployment method? Has anyone ever been in an aircraft where a aircraft parachute has been deployed? What do I do if there is a problem with the attachment position in an aircraft where the CofG is close to everything, or where do you place the connection?

The reliability and security of an engineering design is given a rigorous design review of which the probability of failure is a part. First we look at the consequences of failure of the piece of equipment. We assign a failure consequences number. A consequence of minor nuisance gets a small number, many deaths and large financial cost the most. Just large financial costs gets a high number! Then each subsystem gets analysed by a team of independent experts and analysed for failure in a dedicated set of ways, over/ under temperature, load, height (tanks etc) and so on, including any other failure. Then each failure system is analysed for ways of preventing the failure, the corrective action. If it is human intervention the probability is 0.5 of failure. If the failure is owing to an equipment failure then maintenance, replacement within failure times, and replacement are looked at to mitigate the impact of the failure. This is a quick, and lacks some details in trying to keep it brief. When it came to a separation of the moving parts of a gas turbine, we used to say it was contained within the casing until the Qantas A380 engine incident. We don't always get things safer with this system, but it is far safer than no system.

Thanks "emu" you have clarified the science better than I ever could. I am at the bottom end of the spectrum so I am not so good at explaining things.

I find it very interesting, fun and not so difficult. I have retired now but still dabble.

When you are determining the safety of a system for controlling some piece of apparatus you have to look at each part of that system and them calculate the probability big failure. Should the probability be low then a physical inspection of the system is required at a frequency that is significantly shorter than the failure probability. If for example you have a control system that keeps the altitude constant and uses a human that can only see an altimeter, nothing from outside then you have to put 0.5 as the probability of his failure. If an electronic control system is used to keep the altitude then the system usually calculates a fairly low probability of failure. So an inspection/testing regime will be developed. Hopefully an inspection is calculated to be greater than 100hours. I did a lot of work with TMR (tri modular redundant) system uses three computers checking each other and all three must agree to execute a control function. These systems of have a reliability of one failure every million operating hours. I designed these systems for gas turbines.

It's what the requirements are for failure probability. I tend to agree with it. It's about a decision required to stop a catastrophic result. It's an Australian standards thing.

During my career I did a lot of failure probably studies. The surprise to me was that if a human was responsible for preventing a failure then the failure probability of the human was 0.5, limit switches were 0.0001. in other words a human is the weak link, making a wrong decision every second time.

My project has two engines. Each can have two spark plugs, I have chosen a single on each engine to keep the weight down.

Sure that both mags on a single drive has less reliability. But the loss of reliability is so low that it's minor. Mooney's J series have Lycoming engines in this configuration. You can get a dual conversion kit, if one gear goes, it will probably destroy that drive and all drives will be cactus. How many Mooney's have come down owing to the mags? None that I have known, I elected to overhaul the existing one. If you want to increase the reliability of your aircraft with such little increment in reliability buy a twin.

I use carbon infused nylon. It's specific density is a little over 1. The parts have to be redesigned to take advantage of nylon/carbon features. Steel .050 inch can be replaced with 0.250 inch nylon/carbon with a honeycomb centre of 30%,-40%. What really has to happen is that every printed part has to be re-engineered to seeing it can be replaced.

I have been experimenting with 3d printed load parts to replace steel parts