turboplanner

IF it floats too far, get the speed over the fence back a bit. If you only JUST arrested it last time add a bit. IF you hang it up too high above the ground, the forgiving ground effect won't help you much and you could drop a wing. . Distance about 1/2 wingspan above ground level and doesn't work over trees. Less with HI wing. The air is "alive" so be alert for variables. Nev

It doesn't have a floating problem.

The US standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches. That's an exceedingly odd number.

Why was that gauge used?

Because that's the way they built them in England, and English expatriates built the US Railroads.

Why did the English build them like that?

Because the first rail lines were built by the same people who built the pre-railroad tramways, and that's the gauge they used.

Why did "they" use that gauge then?

Because the people who built the tramways used the same jigs and tools that they used for building wagons, which used that wheel spacing.

Why did the wagons have that particular odd wheel spacing?

Well, if they tried to use any other spacing, the wagon wheels would break on some of the old, long distance roads in England, because that's the spacing of the wheel ruts.

Who built those old rutted roads?

Imperial Rome built the first long distance roads in Europe (and England) for their legions. The roads have been used ever since.

And the ruts in the roads?

Roman war chariots formed the initial ruts, which everyone else had to match for fear of destroying their wagon wheels. Since the chariots were made for Imperial Rome, they were all alike in the matter of wheel spacing.

The United States standard railroad gauge of 4 feet, 8.5 inches is derived from the original specifications for an Imperial Roman war chariot.

And the Imperial Roman war chariots were made just wide enough to accommodate the back ends of two war horses.

Now the twist to the story...

When you see a Space Shuttle sitting on its launch pad, there are two big booster rockets attached to the sides of the main fuel tank. These are solid rocket boosters, or SRBs. The SRBs are made by Thiokol at their factory in Utah. The engineers who designed the SRBs would have preferred to make them a bit fatter, but the SRBs had to be shipped by train from the factory to the launch site.

The railroad line from the factory happens to run through a tunnel in the mountains. The SRBs had to fit through that tunnel. The tunnel is slightly wider than the railroad track, and the railroad track, as you now know, is about as wide as two horses' behinds.

So, a major Space Shuttle design feature of what is arguably the world's most advanced transportation system was determined over two thousand years ago by the width of a Horse's ass.

The Jabiru 170's (esp the C & D's) are fantastic aircraft. The longer wings give you a better flare and take off a little sooner. The shorter wing 160's fly great to but I prefer the bigger wing jabs. I have not notice poor x wing performance but because the flare is a little longer you have to be able to manage you technique for a slightly longer period.

Are you talking about the pre-AD or post-AD?

Probably right Sunny

It’s the factory you need to talk to; maybe someone could introduce you.

While we're considering theoreticals, would you recommend rebuilding one that had been submerged under the sea?

I've read the history of the various jab aircraft. How one thing developed into another, and many stories and writeups online.

 

I seek informed wisdom / comment from others regarding the development of the J170D

 

Big wings, big tail put on to address hot weather climbing issues. Numerous tweaks elsewhere to improve overall flyability.

 

Numerous pilots say it has made the plane much more sensitive in crosswinds, wind gusts etc- having the low wing loading.

 

Why would a mfr go down this path, and not simply increase the engine size to address these performance issues ?

That is : why not increase from 80HP to 100HP (putting aside that that is not a Jab engine size) , allow the aircraft to put on a bit more AoA and thrust ?

 

Here is what I have come up with : please comment.

 

a) big wing assists meeting 45 kts stall at 600kg MTOW for both RAAaus, thus reducing approach speeds, reducing criticality of thrust/AoA on a high wing load aircraft during landing

b) going from the 80 HP to the 120 HP engine would fix the climb rate etc,

- but now the airplane would be beyond the original design intentions and objectives with the 120 HP motor during cruise, and thus the extra weight , together with not running the engine/prop combo in its most efficient configuration for the original design envelope of 100 kts cruise would yield poor fuel economy.

c) very low cost to add wing, but weight and cost to add the 6 cyl engine.

d) or... I am wrong with my thinking that more thrust would mitigate the slow climb rate in hot and high is false

 

There are a few J160Cs around with 6 cyl 120 HP motors, their owners seem very happy with overall performance.

 

?

-glen

Settle down RF, I flew the J160 in Victoria and was very happy with it. Then we got a J170. The theory we were told, was that the J160 didn't have enough lift of hot days in the northern part of Australia with its high temperature atmosphere. From all reports the big wing worked well in Northern Australia, but in the much lower ambient temperatures of coastal Victoria the lift was much greater (do some calcs on density altitudes for north and south and you'll see the difference), Now in this more compressed air the new wings stuck out a lot more so gusts from one side required a lot more stick concentration. On top of this the fuselage length was very short coupled from CG point to rudder in the J160, so if you copped a quartering wind and were coming in on crossed controls (as we were all told to do) we were often doing it on maximu rudder authority. If we then copped a sudden gust just as we rounded out, the upwind wing would be shoved back, we had no more rudder authority and the aircraft would start to rotate in the upwind direction. Naturally we were told it was the pilot's failt and I spent a lot of time and money learning how to round out and land with the nose wheel about 150 mm above the ground, so it was possible to handle the gusts. A few months later an AD came out and the aircraft received a strake and from memory bigger rudder, and you neven hear and bad reports today. If you want to redesign the aircraft for Jabiru, the J230 would be the one I'd use as a starting point, but I think they have it about right now.

.....Big Red was asked to give a talk to the Coopers Creek Flying Club entitled "How to perfect your wing overs underneath the tree canp[y, and question time went on for an hour until a little man at the back announced..............

.

My core challenge to where you are coming from - and I understand and accept where you’re coming from - is that if you as an association are requiring anything like a “benchmark” that only allows registration and operation if that benchmark is met you have defacto created a design standard ... and that is in direct and complete opposition to the CAOs where all homebuilt airframes are not designed to any standard.

 

The conflict between what people may expect or accept as reasonable and what the requirements under the CAOs are is the core of the conflict.

I’ll put something together to explain it.

.........there's a 50/50 chance she'll do a noseover (avref) straight into the dirt and I won't have to worry about her.

It would be rather impossible to fit 4 or 5 point harness to many planes. While they are the best and I'd see the 5 as the deal as you can slide out of the 4 point. Nev

I think there's a bit of a mixup here between the applications.

A race car these days usually has the seat back inclined well back which lowers the centre of gravity of the driver, reducing roll by a small %.

Crashes where the car slams into something; the brick wall means the driver can slide down through the waist belt (or "submarine), so the fifth belt is anchored to the floor beween the driver's legs. With some of these belts, if you want to get out in a hurry the lower strap grabs and you have to sit back down to release pressure.

In the aircraft application, very few pilots are killed by a head on collision on the ground; the most obvious benefit would be in a nose over where the aircraft is likely to spit the pilot down onto the ground. In addition, most aircraft seats have an elevated cushion and upright squab and submarining is not so common.

Except how does that sit with the tech manual? You must use three point harness but raaus take no responsibility for airworthiness - you must have build indirections to show acceptable build yet neither raaus nor the inspector can tell you it’s wrong.

 

And all of this is in front of the still untested what can raaus do to a member or non member who contravene a written requirement not required by cao and not enforceable as other than an breach of a membership obligation - what actual sanction is viable against a member who fails to have adequate by raaus standards documentation for something that is not a statutory requirement but an admin requirement.

 

Raaus have not done them any favours by having documentation that is very poorly drafted that would need to to be tested with a member disciplinary system that I itself is very poorly drafted and would likely not stand up in any review for anything less than bringing the raaus into disrepute.

 

I do not question that failing to follow a standard would be a consideration however when the caos under which anything not factory delivered is operated at own risk and raaus have no legal ability to Rufus registration or to direct any design in any real way its of limited applicability. Exactly the same as attempting to apply a manufacturers mandatory change to kit/plans built aircraft of same/similar design - there is no actual authority to do half what some people want raaus to do or what raaus have tried to do In the past.

I could respond to virtually every line of that, but it would be too close to giving legal advice and I'm not a lawyer.

You are looking at most of those issues from a prescriptive regulation point of view, whereas I'm look at the same things based on a benchmark/self administration point of view, and don't have a problem with them. Everyone in the chain of responsibility these days has a duty of care to prevent every forseeable risk.

So for example if you are building an aircraft and the benchmark is a three point harness you are responsible for using nothing less than a three point harness and you are responsible for engineering the strength of the harness, the mounting angles and the mounting strength etc.

So why would an authority want to assume liability risk by getting involved in the design? You screw up the design, you pay when a plaintiff wins his case.

As far as compliance and enforcement is concerned, I've mentioned other Associations many times over the years who have installed systems which have ensured very high standards of safety and incorporate human rights safety nets.

The "testing" that you mention will come with public liability lawsuits, so once again only targets the people who were found negligent.

.....doing ramp checks and......

.......run around Tasmania, which takes 45 minutes. His keyboard privileges have been taken away.

That's a very interesting design in #13351, but being made in China is likely to cough its guts up at the 15 second mark.

Turbo's Cone project is slilghtly different and backed by several trials. Initially Turbo didn't worry about aerodynamics, just took a 2" dozer bolt, wrapped in paper and launched it the way you hand launch a model glider. The aircraft repeatedly flew a pretty arc, so was considered a success. The paper shell was protected by car roofs when the craft landed, but the new cone shape carbon fibre shell should handle concrete comfortably, and ..............

I feel nothing but rage when stuck behind "Bob an Janice" at 75 kph as they point out the sights

How is that different to flying a Drifter in the 1000 foot circuit?

Yenn,

If you take the words of Tech Manual issue 4 as being legally binding then lap sash is not acceptable - see sec 3.1 para 3.1 ©

 

The whole issue of is the tech manual actually legally enforcable against a builder or owner has not been tested but is arguable in many respects - in some respects the legal enforcability of whole slabs of the tech manual are questionable.

 

Apart from is it legally allowed to have a lap sash people need to make the assessment of their personal risk tolerance when they come face to face with any aircraft that did not roll out of a factory as a certified/type accepted airframe.

If you build an aircraft you are responsibls for the safety. If there are safety recommmendations or benchmarks or standards and you opted not to comply, no one comes along like they used to and forces you to meet that standard, but if there's an accident and someone is hurt, you've pretty much made it an open and shut case. That's the way it works now.

Now Caravans/Motor -homes:

It is my humble opinion that ALL vehicles should travel as close to the posted speed limit as conditions allow.

In city traffic I would agree with you; and most towing vehicles these days can maintain traffic speed witha 2 tonne caravan.

Startability and gradability come into play in hilly streets, but they are close enough to traffic speed and there are usually multiple lanes in cities these days.

However, out on the highways, opther factors kick in.

The first one is recency. Semi trailer drivers will usually know the road quite well, because they travel in the area frequently and they can just their mirror width to about 50 mm and tyres vs lane markers by abot 50 mm because they are sighting along the trailers. On the other hand the caravan driver will usually be at least 12 months out of date with the road, and probably needs about 400 mm clearance and can't see the lane markers.

Next is reading the road. If you're cruising down the road and a semi is inching up behind you his cruise speed is higher than yours. If it has taken him five minutes to get close enough to pass, when he gets past he will be drawing away at the same rate, so it makes sense, in passing areas to drop back 10 km/hr or so and let him come past. Your trip time reduction will be virtually zero.

Next is why vehicles travel at the speeds they do. Most semis will be on 103 km/hr actual which is where the road speed governor is set - 100 speed limit and 3 tolerance. They work to that speed because if you add a 103 cruise over 250,000 for general semis and 350,000 per year for line haul, and compare that with say 98, you will see what time they would lose per year if they didn't.

On the other hand pretty much all out passenger towing vehicles are power-limited when towing a caravan over 1700 kg. While they are quite capable of cruising at 100 km/hr on the flat with a tail wind, they are limited by gradability and wind resistance, and if you hold your foot flat, a staggering increase in fuel consumption.

The crossover point where wind resistance is not a significant power factor is around 8- km/hr. so you will find some drivers cruising at 80 to get economical cruise.

You will find some semis cruising at around 92 for the same reason if time is not a factor for them.

Most caravan combinations will be cruising between 85 and 95 for fuel reasons.

Most frustration occurs when a slightly faster vehicle is wanting to pass. I will usually call up a semi if I see him behind me and offer to pull over up ahead but most say "No"; they can judge things better with me on a stable cruise speed. I will also pull off for a following car. Time lost doing this is almost zero, because temporary changes in cruise speed make virtually no difference in trip time.

Have a look at these times, where speed has been reduced for 100% of a 200 km leg, and you can see that if this only hapens say 5% of the time you're losing virtually nothing.

200 km trip:

100 km/hr - 2 hours

95 km/hr - 2 hr 6 min

90 km/hr - 2 hr 13 min

85 km/hr - 2 Hr 21 min

80 km/hr - 2 hr 30 min

Satisfied that they had armed themselves with more Covid documents than the AFL, the group took some time to look at the Drifter. All agreed that they had never seen an aircraft like this which showed the popularity of this unit which looked more like a brick elevator than something that might fly, but ................

.....Victorian get out of prison free card as well as a NSW Transit Visa and a South Australian Deed of Agreement never to enter that State, then ......

".............faster than Faetas, and have a better landing attitude and probably land at 22 kts." Although he wouldn't have stamped the video "bull from bone", or .......

[ATTACH alt=image.jpeg]55983[/ATTACH]

My cousin's son was flight engineer in Gulf War 1 and 2 in these. A very unusual aircraft. The Flight Engineer sits between Captain and First Officer and operates the throttle and an outer engine is shut down for long range cruise. The aircraft had a missile defence system, and could knock out submarines, so they were set up for very long range. They coul fly from WA and search the southern ocean around Antarctica and did endless hours north of Australia in surveillance for boat people. I'd hate to think how many hours they have on the frames, and I don't know whether they would have the carrying capacity and performance for fire fighting where a lot of steep turns and sharp climbs are required. I'd think the crew cost and crew layout wouldn't be ideal for quick decisions with gum trees and smoke all around.

Hi Turbs, can you please summarise those things which haven't been done or direct us to the post?

WX00147 is a copy of the Sport Aviation Self-Administration Handbook 2010

In it you will find CASA's honey coated words, nevertheless clearly pointing out that we are responsible for our own actions.

Note the reference to a benchmark, Australian Standard 3806 - 2006 we could rely on to help us bring our members into Compliance.

Note the requirement for an SMS (a) in the last para Page 11 - note the words. and (b) Safety Culture, Implementation Page 19 - note elements.

Enforcements P16 - note who must ensure compliance.

Words like RAAOS are to.....same meaning as must.

The items RAA didn't comply with are spelled out in a series of posts on this site around June 2013 - 3 years later.

I'll just concentrate on the main item, and SMS here.

When several RAA people including a Board Member who knew the implications of not putting an SMS in place tried to introduce one, they were beaten up by a horde of RAA protestors who just wanted freedom, and had no idea they were risking their houses, and both the person, who worked in the Mining Industry and knew what was needed and why and how to write one, and the Board member left this site.

Eventually, in the RAA Inc days a tiny SMS was introduced. RAA Ltd members who know what an SMS should look like might be interested to see what's in place now, along with the other requirements the Handbook introduced, which very clearly we should have been complying with from 2010.

WX00147.pdf

WX00147.pdf

WX00146.pdf

Given the level of expertise here, I can see a new standard emerging.........the Australian Standard Fread (ASF)???

Like the NZ switchback.....

Hi Turbs, can you please summarise those things which haven't been done or direct us to the post?

I'll see if I can find it; may have it as a file

Thanks OME, a brilliant assessment and attention to detail.

Things like correct choice of fasteners are often at the base of great products that last a lifetime.

OT; That information is just as valuable. the Grade 8 bolts used to assemble the International ACCO were one of it's best selling points compared to the English and American trucks it replaced.