old man emu

As a kid I saw a demonstration of a wood turning machine that had a template follower, which is what that copier basically is. Same as the key-cutting machine at Bunnings. I wonder how the templates were made. It's a chicken and the egg question. I was interested in the use of the press to clamp the individual plies together while the glue set. And I wonder what the glue was. It didn't look like Resorcinol, which from my experience is purplish in colour. And I don't think the reporter did much more than pose for a photo-op sanding down that prop. I reckon that would take a lot of experience to prevent going too far.

Ever wondered how a wooden propeller is made? Watch the machinery, not the eye candy.

3-speed gearbox. 0 to 14 mph in first. 15 to 30 in second, then 30 to 64 mph in third. We are talking about a 45 cu in engine 4.75:1 compression ratio producing 25 HP at 4600 RPM. The bike will happily chug along in second gear. with 30 lb-ft torque at 2400 RPM

Yes, but not on the taxiway I described above. It was on the original taxiway at the point indicated by the arrow. There was a enclosed drain under the taxiway made up of short lengths of concrete pipe. In several places the top of the pipe had cracked and the soil on top fell through, making a hole. The whole aerodrome had been slashed not many days before the incident and cut grass was laying over the hole. It was impossible to see any hole, even when walking on the taxiway. What made matters worse was that a con marker had been placed over the end of the pipe, so you didn't even know there was a pipe there. For the pilot it was an unavoidable accident. The taxiway was closed off at that end, and the aerodrome owner had a crew dig out the pipe line a few days later. This shows the hole (at the start of the tape measure) and the point where the prop hit the ground (at the case of the tape measure) You can see for yourself that it would be impossible for the pilot to see that hole.

I would say,"essential", but rarely created. That's ridiculous because there's always clear space close enough alongside to lay out a taxiway. We had 45 metres between a boundary fence and the runway, so we set the runway-side of the taxiway 15 metres from it. Then made the taxiway 10 metres wide, leaving 20 metres to the fence.

Exploring many country town aerodromes, I found that taxiways from terminals to the ends of runways are very rare. When planning The Event, I was lucky to have the room to lay out temporary taxiways the full length of the runway. That eliminated any need to backtrack when going to or from the marshalling area. As a result we were able to dispatch the entrants at roughly 90 second to two minute intervals with very good line-astern separation. It also didn't create the need for returning aircraft to go into holding patterns while preceding aircraft cleared the runway because we included exit lanes from the runway to the taxiway at 200 metre intervals. The wind helped. The end of the active runway that was being used was only 400 metres from the marshaling area, so aircraft were just in the early stages of climb out as they passed the admiring public. During the departure sequence, the place looked like Mascot on a Monday morning with planes following each other along taxiways to the runway threshold.

It is a misconception that ground running without the cowls on is Okay. The cowls don't simply take care of the aerodynamics of the airflow on the outside of the aircraft. Those cowls and baffles have been designed to direct cooling air over the cylinders, especially the rear ones. It's usually OK to have the cowls off when doing something like tweaking the ignition timing as the engine is only running for a few minutes at low revs. But to taxi an aircraft out to a runup bay for full power testing without the cowls shows a lack of care for an engine.

That would put you into the team that advocates full power, straight out of the box. I'm not commenting on which team you are in, just noting that we have one in that team and no one has nominated for the opposition. The US Army instructions for running in the engine of a WLA Harley are given below. I've left out the bits about checking for loose nuts and bolts on the frame and that the chain oiler is working. Those engines were designed in 1937 and made using the metallurgical knowledge of the time. As Nev said, modern motors don't have to be nursed like this. RUNNING‐IN NEW ENGINE (OR VEHICLE). a. A new motorcycle engine or newly overhauled engine must be given proper “break‐in” consideration for at least the first 1,000 to 1,200 miles of service. b. At first 500 miles, drain oil tank and refill with fresh oil. Check front and rear chains (step b above). Thereafter, follow instructions in Maintenance Operation section. e. Following pointers must be observed when running‐in new engine or newly overhauled engine: (1) Do not exceed 30 miles per hour during first 100 miles. (2) Do not exceed 35 miles per hour during next 200 miles. (3) Do not exceed 40 miles per hour during next 400 miles. (4) Do not exceed 50 miles per hour during next 500 miles. (5) Avoid use of low gears during break‐in operation as much as possible.

And that brings us back to the very beginning of this thread - ignorance of this area of aircraft performance. Or a mere slip of a lass. Don't forget that there's no sex discrimination in aviation. That resultant, while within the envelope sure is closer to the rear limit than some would care to fly with.

Honestly, I think Aro understands the concept of W&B, but not the mathematics of it. You can't point to a tangible location of an aircraft an say "That point is in the CofG range. What graphical representation the CofG envelope shows is the answer to the summation of the individual Moments. An individual Moment is calculated using the distance of the location of the weight from the aircraft datum point multiplied by the amount of weight. As Aro says, the datum point is designated arbitrarily by the designer, most often to eliminate negative values for a Moment. In balancing radio controlled models, one usually takes the location equal to 1/4 of the wing chord, because that's pretty close to the Centre of Loft and allows you to add weights to eliminate a tail-down tendency, which of course leads to stalling. In a people-carrying plane, it is easy enough to measure things with a tape. So the reference point can be anywhere. Some designers even put it forward at the tip of the propeller spinner so that the calculated Moment at each station is positive.

A complex question that will have two teams battling it out til Doomsday. One team says to run the engine at lower power settings for the specified period. The other says fire it up and give it full power. That was effected by towing a plane to the start of the runway, starting it and taking off. But that was for WWII radials. With your Europa engine, you have the advantage of temperature and pressure gauges to help you monitor those factors. So you won't be worrying about cooling. However, I can see a bit of poor communication in this: you will have needed to run the engine for a minimum of 2 hours without any problems . What exactly did the writer mean? I see that as good advice, simply because by running the engine while on the ground, you can check that everything required for proper combustion, and hence power development, is set correctly, and that nothing has been left loose or has come loose. In that sentence I cannot detect any reference to things that happen when we first run an engine, such as bedding in bearings and rings and valves. Perhaps Europa bench runs the engine before signing it off for sale. In some engines the manufacturer specifies that non-detergent mineral oil is used for the first few hours. One idea here is that the oil will burn and soot will fill those minute surface unevennesses. After that period, you can switch over to detergent mineral oil, or synthetic if specified.

Will someone let me know if I am correct here in the Physics of levers?

You can say that Piper and Cessna added a fairly big fudge factor in establishing the CofG envelope. Maybe they put Human Factors above aeronautical demands in their design specification. It's probably true that you would bend an aircraft on the ramp by overloading before you felt the effects out on the runway, IF the aircraft was a certified type, or a commonly built experimental. However, it's the one-off homebuilt that could give a nasty bite it loading was not correct. What sort of crazy numbers did you use, and where did you place the weights? Here's a thought: See how the manufacturer has given the Moments at several station locations for various loading options. Looking at the cargo carrying options, the Moment aft of the crew seats is given at a single station. In physics calculations, of which W&B's are a type, it is assumed that the weight of an object acts through its centre of mass. That's OK for a regularly-shaped object, but what if you were carrying something highly irregular in shape with very scattered localised weights? I think that the answer to that question lies in having faith in the designer's fudge factors. As long as you remain within the weight limitations for a load area, and the total W&B values put you in the envelope, she's sweet to go!

Aro seems to be talking about two different, but related things, which I'd ask him to clarify. Having the CofG within the approved range ensures that the aerodynamic controls of the aircraft are able to provide full control of the aircraft. Too far forward and the nose cannot be raised for take off. Too far back and the nose cannot be lowered to keep the Angle of Attack below the stalling angle. Another reason for knowing the total weight of the aircraft is that there is a limit to the lift its wings can produce. Theoretically, you could hang a one tonne weight at the zero Datum point and the Balance would be mathematically correct, but the plane would never get off the ground. The C-210 might be an aircraft that can be loaded in such a way that at the end of a flight, the weight loss due to fuel consumption might result in the CofG being outside the envelope resulting in uncontrollability issues at the flare. So the manufacturer gives a warning. Such a warning might be unique to this aircraft and not a factor for many others.

I felt neglected that CASA didn't send some inspectors. Not that I wanted anyone "booked", but I figured I jumped through CASA's hoops to get the approval, so I should at least meet the the people who should make sure they are set up correctly. Maybe it was because when I was first engaging in cross-country flying, my friend was working towards his Commercial. So every flight was done with Full Reporting which required ETAs at designated points and reporting at set intervals. And all done with map and whizz-wheel. As I was preparing the conditions for the event, there was a lot of conversation on this site about simply whacking location coordinates and basic performance data into a device to get the data to complete the plight plan form. While I accept that it is efficient to use the best tools available to us to do a job, we must have the knowledge and ability to do the job with inferior tools, even if that is not as efficient. What worried me from those conversations, and was borne out by the entries I got, was that the basic knowledge was not being insisted upon in the initial introduction to aerial navigation. I don't know what examiners are requiring of applicants when testing navigational skills, but I am of the opinion that software should not be used until a pilot has completed ten or fifteen flights of increasing complexity using the basic tools for planning.

That's why wives and girlfriends can never be convinced to go flying with you. Body mass is something that I have never been asked about when being given a seat in a light aircraft, and a few years ago I had more than I do now. When I look at the specs for an RAA plane I always see how much fuel it can carry with two 120 kg bods in it. Years ago, it was standard practice to use 75 kgs as the default weight for a passenger. Now I would prefer 100 kg because the average body mass of the population has risen over the past 50 years.

Don't forget that the figures given in the manufacturer's POH are performance at sea level in the International Standard Atmosphere (15C and 1013 hPa). Everyday, and throughout the day, an aircraft's performance will be changing as the atmospheric conditions around it change. I reckon that a Toora (1300 AMSL) on a morning when the temperature was Zero and there was a typical autumn High pressure cell sitting over Central NSW, a brick would climb like a fart in a bath.

I wonder what the AN35 signifies in his identifier block. The weighing was done ten years after the pilot's course, so he had probably left the Service.

It must have been produced in Australia as the VH- part of the aircraft identity was already printed on the page before the individual letters were typed on. Maybe some older person here might know the bloke who did the weighing - B.D. Linard

I hope I'm correct in thinking that you mean by that statement that you are making a distinction between the way you think and the way I do. Let's say that you think using the graphs is the best way to ensure the balance is correct, but I say that doing the calculation is the right way. As long as we both get an answer that's within the envelope, does it matter that we got there differently? No a jot. I would have thought that the designer would have provided the datum point and forward and aft limits. But then I think of the plans I have from a 1930s magazine for a Gere Sport (one was built at Cowra). I don't think I saw any of that data in the article, so I wonder how the bloke at Cowra worked it out. When I go through the drawings and notes for Arthur Butler's BAT-2, I'll have to keep my eye out for that date.

Honestly, with access to the several graphs present in a POH, there is no need to have even a modicum of arithmetic ability. Just follow the instructions in the POH. Here is Page 6 of the POH from, admittedly, a factory manufactured aeroplane. Start at the left hand axis (weight of object). Move from left to right until you hit the relevant line, then go vertically down to the bottom axis to get the necessary number. Once you have all those numbers you add the wieghts to find the total load. Then you add the Moments to get the load Moments. You have to also obtain the aircraft's weight and moment from the handbook that is specific for the aircraft you are using, not generic. From this page, I would use the AOW which doesn't require you to accurately measure the amount of oil in the engine. Just check that it is to the "FULL" mark on the dipstick. Once you have done those additions you go to the W&B envelope chart. Again, start at the left hand axis from the total weight and go across to the right. Go up from the bottom (index units) until you intersect the weight line. If the intersection is within the bordered area, you are OK. The area of the Normal Category on the graph includes the Utility Category, which is a restricted W&B combination that allows for more strenuous forcing of the airframe. It is probably possible for the W&B for a slim pilot doing a few circuits with, say, 1/4 tanks to have the in the utility category area, but that's OK for the task of shooting a few circuits. Here's something to think about. If your bladder can take it, and you decide to fly until you've only got your 45 minutes' reserve left in the tanks when you land, it might be possible that the W&B is outside the envelope. Who calculated W&B at the end of a flight?

You were one of the lucky ones. Experience is a tough teacher. Another thing that perhaps gets overlooked is Density Height and its affect on performance. We might not have the heights to get over that the northern hemisphere people do, but our typical surface air temperatures and higher air pressures do need to be conidered. However, sometimes these make for strange results. At sunrise on Saturday the air temperature on the aerodrome was 0C, air pressure about 1030 and aerodrome is 1300 AMSL. Would that mean aircraft would make submarine approaches?

Goodness! I didn't realise that this W&B topic was not being taught, or if it is, not being practised. Is it that when we are learning to fly, it's usually an hour's flight with just an instructor and yourself so that the loading would never make the balance go out of the envelope? That introduces a habit so that later on, we don't consider balance if we use the aircraft for holiday trips. I also wonder if people are taught to consider the need to always be flying at cruise power. Do people ever think to decide on a suitable ground speed and see how they can use the wind to adjust their power setting. Maybe with the wind at your back, you can throttle back atad to and still get a normal sort of round speed. Or am I simply an old fuddy duddy who likes the DIY approach to calculation and disdains to use some electronic gizmo?

When I designed the Flight Plan form for The Event, I included a section for recording fuel usage and another for calculating the weight and balance moments of the aircraft to check that the Total Moment was within the aircraft's W&B envelope. I don't know if it was ignorance or lack of data, but most of the entrants did not complete the record of calculations for W&B. Most did put in the weights, but not the related Moment. Only one entrant actually noted the fore and aft limits of the Moment based on the weights. Has this important safety and performance item ceased to be stressed? Have manufacturers stopped putting those graphs on the POHs? Have we adopted the idea that if we can close the doors, the loading is OK?

But the younger generation don't know those traditional songs. I suppose in these days of young people shacking up together, If I was the marrying kind is old hat.