Jaba-who

If I didn't have such a backlog of projects I'd be redesigning my airflow to come in under the spinner and rise up thru the fins. Updraught cooling works well for pushers like Rutans.

 

Would this mean having the outflow going up through the top cowl or turning over and going downward again after the engine? 

just wondering what evil effect, if any, would hot air etc have in blowing across the windscreen. 

It's one way of making sure they don't droop and melt onto the fins. Keeping leads clear of the cylinders is essential.  After shutdown  it's a pity the heat can't be let out of the cowl better. Nev

 

Never seen an ignition lead melt. But that could be because I have mine zip tied together and they stay in place and away from the metalwork. 

I’m not so sure the leads being in the ram air ducts  is as big a negative deal as you might initially think. 

there’s two potential issues - effect on the leads and effect on engine cooling. 

Obviously there’s less heat to the leads  during flight compared to on the ground due to airflow cooling them but I guess they heat up after shutdown for a while. But the practical experience is that by the time you descend and land and taxi at low power the engine temps are pretty low unless you are stuck on the ground for long periods I guess. 

As for engine cooling effects. If you look at the positioning of the leads inside the ram air ducts they are to the sides well out of the way of the actual (preferred) air path. 

the preferred air path is through the fins from top to bottom ( well inside the path of the leads). 

if anything you actually don’t want the air to travel down the sides where the leads are but to be forced to track inside and down through the fins. 

I’d guess they might serve a positive purpose being in there as evidenced by Coinz experience. 

Not saying you are incorrect Nev but my McFarlane 2018 catalog has oil cooler part numbers for every single engine cessna and piper. That would cover every engine family from Lyc and cont.

 

It’s my understanding ( could be wrong as I have never flown in the conditions below) that though there is an oil cooler made for every model of the cont-lyc range there is not a requirement that they are fitted. If being flown  in cold locations they don’t need them and they don’t need to actually be on the engine. 

Airsickness will stop after acclimatisation. Ask any DAME, its quite common when you start aerobatics.

 

Ah. Well...   maybe

I have known a couple of student pilots who gave away training because of intractable air sickness. One in fixed wings,  one in helicopters. Both tried everything they could find to stop it and both got  up to “double figure” hours with an instructor before deciding to give it away. Neither was allowed to go solo by the schools because of the issue. 

Nope. Had the reverse. 

just got a bill for a landing at Mareeba but never landed there. 

it’s for a date I was flying out of Atherton and the two airports are in the same area so they have probably picked up my call sign when my Atherton call triggered the Mareeba radio recorder. 

I have yet to get back to them about it , but they have never been a problem about these errors in the past. I have had a few wrong bills and they have always been very good about reversing them. 

Can’t see  why there would be an issue with the legality of a third party sending bills. It’s done all the time in business and government. I do it myself. Actually I use two - a billing company and then a debt collector company if the bills aren’t paid to the first company. Vendor uses a billing service as an authorised representative. You’d have a hard time arguing that it wasn’t valid. 

There's a difference between meeting certain standards and self declaring you do. It's not just a matter of HOLDING a driver's licence either. IF you cover up a condition you wont get an easy ride if the excrement hits the fan. After a certain age or having some certain conditions your doctor gets involved . That's how it should be..  It's well documented that under high stress conditions your heart rate can go to figures like 160 plus. If you heart is weak  or you have blocked arteries you might just die in flight  or after landing . Properly treated and monitored people are generally lower risk than the" I've never been near a doctor in my life" types .Nev

 

Actually that’s not true at all and has been proven to be not true and is why USA and Britain have moved away from formal medicals. Also proved to be untrue by our own RAA system of self certification. 

Generally, declaring you are fit has proved itself to be exactly the same as meeting the standard.  

There are just not planes in USA , Britain or  RAAus pilots dropping out of the sky from medical incapacitation. Yet we know that many RAAus pilots are in RAAus because they have medical issues and can’t get CASA type medicals. ( and often had them for long periods ) 

That's similar to what I was saying, and only the instructor has the answer to that, however I wouldn't go on a vendetta against the instructor. There is a clear weakness with self-reporting under the CASA system, but rather than go up several scales to a Class 2, I think, for 600 KG MTOW, the long established motor racing benchmark of a series of passes in nominated tests would both match what happens now with self- reporting (if the pilot is disclosing fully) i.e. no more stringent than what is supposed to be happening now, eliminate failure to declare, or false statements, and most importantly, not throw unreasonable liability on to the Doctor (since he's simply noting a pass/fail on standard tests).

 

To cite the case of the instructor in the incident. 

It turns out he has a benign tumour in a location where frequently nothing is findable on simple “in-the-consulting-room-testing”.  Sure it’s there on a CT or MRI but you don’t send people for those when they have nothing to find and no history. Sometimes there are things to find but often not. Even in retrospect patients will tell you they had no discernable  signs or symptoms. 

The tumour just quietly sits there and gradually enlarges. Typically some small event happens in the tumour ( often a blood vessel gets blocked or compressed) and this causes a bit of local tissue swelling and that sudden swelling causes a pressure effect and a seizure happens “out of the blue”. 

But it that’s the same for a number of rare things but you have to remember that by far and away the most common cause of medical incapacitation is food poisoning from eating something within hours of the flight and that is never ever going to be found in a medical conducted way before the flight. 

I wonder what fraction of RAAus would be forced out for medical reasons if the thing actually was enforced. My impression is more than half. Most people over 70 would have something is my guess.

 

Its not just the “forced out for medical reasons” it’s also those who would say it’s just not worth the extra effort and cost to jump through all the hoops to drag a pass out of the system. Probably way more than half. 

And if you are flying an aircraft at a non-tower aerodrome - 99% of Australian Airfield’s - then this is not an actual issue is it?

 

So why not manage the issue with operational limits?

 

and FYI the 1 time I did have radio failure at a tower controlled airfield the tower made no light signals and I visually conformed with existing traffic in the pattern and reported to tower after landing.  Not in oz I’ll admit but the Uk follow the same rules on this one. 

 

I prefer to look for practical workarounds rather than putting absolute rules in place when not required.   

 

The one time I had a radio failure I phoned the tower on my blue tooth light speed Zulu headset and after confirming I had enough battery time I got treated like I was on the radio and got brought in as normal but over the phone. Class C at Cairns international airport. Unbelievably great service and it worked fine. 

Support, Quality and an endless supply of ideas and cad ware are the main things to look for. XYZ Printing has hundreds and thousands of free dowloads for printing.

 

I have a      dA Vinci 1.0 Aio   all in one 3D Printer (Scan/Edit/Print) for sale. 

 

The images tell the story. It has had only 14hrs use.    This printer will scan an object and print as well.

 

[ATTACH]41205[/ATTACH] [ATTACH]41206[/ATTACH] [ATTACH]41207[/ATTACH] [ATTACH]41208[/ATTACH] [ATTACH]41209[/ATTACH] [ATTACH]41210[/ATTACH] [ATTACH]41211[/ATTACH] [ATTACH]41212[/ATTACH]

 

I’d probably be more concerned about the first two ( Quality and support) and not be as driven by the last two because they are not product specific. Libraries store their  designs as common format files.  The xyz library as well as about a dozen other libraries that are available are open to everyone. You can have a totally  different printer but still download the files for printing. Same with the cad software. There are a bunch of CAD programs available and they work independently of the printer type. Many are free and are often cutdown versions of the major industry ones. 

The slicer program - which converts the file made in the CAD program to one specific for that printer is the product specific one but seems to be fairly basic compared to the CAD program. Some printers will print files sliced on a range of slicer programs while some require their specific program. 

Roxy,  I actually first looked at getting an xyz because of the scanning capability. The plan being if I hd something that broke I could scan it and reprint a new one  without having to learn to use a CAD program. But in the end I went with a straight printer. I then got an app for my iPhone to scan stuff. But in the end I have never needed to scan anything so never actually done a print like that. Everything I’ve made I have CADed up myself because they inevitably end up being new designs. 

The main use of a desktop 3D printer is for prototyping. It takes a very long time to print an object of substantial size as each layer put down is often only about 1 mm thick. Once the prototype has passed "proof of concept", then the drawing the 3D G-code was developed from can be used to generate the CNC G-code for use in a milling machine.

 

That Ender 3 looks just the thing for an intitial foray into 3D printing. Just note the points in this review: https://all3dp.com/1/creality-ender-3-3d-printer-review/

 

Looks like attention needs to be given to the leveling of the base of the frame - no giggy.

 

Like everything it depends on your budget. 

There literally is a printer for every budget from about $250 up to tens of $1000s with the general principle of “ you get what you pay for” applying. It’s an incredibly finicky pastime and the cheaper you go the more work you have to do to get successful prints and the more failures you get. 

The band of about $1000 to $1500 being the broadly “best bang for buck”  for the home user.  

There are a gazzillion reviews on the internet both written and videos. 

When I bought mine I spent a bit of time researching and when asking the web for the list of the best printers you get a heap of “ my-top-ten” type reviews. In that price band mentioned the one brand that consistently was top of the heap was the Prusa. 

I haven’t had  any experience of Enders but the reviews seem to consistently put it  after Prusa. But they are in two different price bands so that  is what you’d expect. 

Prusa seem to have have gained solid reputation for support. The big issue is that 3D printing is still in the realm of the tinkerer. There are no home level “ works out of the box every time forever with every type of filament”.  No plug and play without learning the ropes type.

And they are a bit like home built aircraft - always something loosening up, wearing out or failing and support is a big requirement. 

Wouldn’t a milling machine be a better idea? Been around for decades and don’t make things out of the crappest plastic known to humankind? 

 

I think it’s “horses for courses!”  

There are some things that can be plastic and would be of the strength required.

Especially if you are designing them yourself they can be redone over and over again till you get them just right. Cheap, easy and don’t need the well appointed workshop. 

Some of the output of a 3D printer can be made really schmicko with post- production vapour  smoothing. 

Of course there’s some things that need to be metal and structurally sound  but honestly once they get to that level I’ll buy aviation grade ones  from Aircraft Spruce.  

I’ve got a Prusa Mark 3S that I got as a kit and have become a bit of a Maker-Nerd I guess. 

I’ve  used it for some Jabiru based stuff but nothing structural or requiring absolute strength. Some are pretty basic due to my just learning.

I just use TinkerCAD to design things and the Slicer program that comes with the printer to make the guide files that the printer itself needs.

 I have tried Fusion 360 CAD program but Fusion 360 is pretty intensive learning and requires a lot of getting used to. so I tend to just stay with TinkerCAD which is a simple free online CAD designed for school kids. It’s About my level! ?

So my list of bits: 

Dash bits - Instrument hole blanking plug

                    Small plate to hold USB extension plug from the sky view. 

Clips to hold sun visor up when not in use. Headphone cradle for the control/battery box on my Light speed Zulus

Camera mount for my 360 Fly “ball” camera on the vertical stabiliser. 

There’s not a lot of things I’ve made for the Jabiru specifically compared to other stuff in the workshop or round the house because I’ve been worried about structural strength. 

Some have to be heat resistant if they are going to be permanent in the cabin. 

ABS plastic has the highest melting temps of the simple,  easy to use plastics and is used for some motor vehicle parts but I’ve seen some examples where even they have melted so I’ve been a bit careful. 

I’d be keen to see what other makers/jab owners/pilots have done and extend my experience. 

I have seen 40 years of industry, government and universities trying to predict the demand for mining and geology professionals. They don’t just get it wrong, they get it 180 degrees wrong consistently.

 

Yep. Usually they employ consultancy firms who have no skin in the game and who direct their findings toward the answer they know will be best accepted by government and this usually involves the answer that will cost the least in the beginning. 

In the end it’s often  the most expensive because the cheapest one fails then there’s the cost of extracting the disaster then the cost of implementing the proper program that should have been done in the first place. 

Was it the government  or was it the AMA ?  

 

Mmm. Far too complex for simple answers. 

In the 1980s (when I was a medical student) they didn’t really cut numbers. 

What they didn’t do was increase them in line with the rapid increase in population.

At the same time they accepted dodgy advice that hospitals would be less needed as people got healthier in the new age of technology and they cut hospital bed numbers and dropped the number of positions for doctors in the hospitals. 

Then Too late, they realised they  had to actually increase bed numbers but by then there was a shortage of doctors at all levels - but especially junior doctors because large numbers of junior doctors could not get jobs here and had left Australia and had gone overseas. ( particularly to Britain and Ireland because there was still the perception that to be seen as a serious contender for specialist training here you had to have been working in Britain for at least some time. 

The decisions about hospital bed  and patient numbers and thus doctors numbers  to treat them was due to a complex interaction  with state governments Health departments ( who pay for hospitals and also who limit the numbers of jobs for doctors in those hospitals), Doctors Groups( the AMA and others (eg Doctors Reform Society in those days) specialist and GP colleges and consumer groups who all had varying inputs into attempting to predict future needs.

( I know there’s often theory that the AMA is in control of this but it’s just conspiracy theorists. The AMA is just a union and has less that 1/3 of doctors as members. I’ve never been a member and in my 20 person practice only 3 are members.  They carry no power or capacity to enforce things against the people with the purse strings -(ie: the state government) . Their entire clout comes from presentation of statistically justifiable and rational opinion. If they talked rot the governments would pay them no heed as they have no say over more than 2/3 of doctors) and definitely not over hospital employed doctors who have to sign contracts dictating what they can and can’t say and do. 

It was the attempts to predict the future hospital and medical manpower needs that was a dismal failure. That’s also a couple books worth in its own right. 

Essentially the then lack of Australian junior doctors resulted in a huge influx of overseas trained doctors ( paradoxically mostly from Britain where the NHS was  in disarray and where heaps of Australians were doing there what the poms were doing here!)

Now  it’s a free for all with just about every university has a medical school and there are as good as no limits on student numbers. Universities get their funding by having students on the roll call so they go to great lengths to make more places and keep them there till they get out the far end of the sausage machine. so now there’s a glut. A medical student having completed the uni training can’t just go into practice. They have to get a job in a hospital as an intern to be supervised through another minimum of a year before they can be registered. So if you can’t get an intern job. You are unemployed. 

Now there are no guarantees that a student will get a job when they graduate and the university gets their funding by getting these students through despite  no job for them. 

In fact it’s now almost a guarantee that some intern doctors will miss out on a job when they graduate. Nearly a million $ of community money wasted on getting them through to go on the dole at the end. 

Its been  like many human endeavours - a pendulum  that swings first one end toward disaster then back to the middle and looking good to overshoot the other way to equal disaster. Hopefully the usual pattern will be followed and eventually it will settle somewhere in the middle. I just hope it’s soon because I’m getting to the age where I’m gonna need a better functioning health system and at present it’s pretty scary. 

Ken, are you saying that "M&M" were assuming there would be a removal of max stall speed with any weight increase?   Or they hadn't thought about the stall speed of 760kg MTOW aircraft? This could cause probs with some aircraft already on the RAAus Register.  Aircraft now limited to 600kg thus keeping stall speed around 45kts at that weight but will increase at the higher 760kg MTOW. The Colt is one along with the RV4 and probably others.

 

There has never been any suggestion an aircraft which is currently rated at eg 600kg can increase its MTOW to 760 kg. 

It has always been suggested by CASA that only aircraft that already are too heavy by virtue of their existent MTOW that fell between 600 kg and 760 kg could be registered “at their current weight”. 

If an aircraft is designed and built and certified etc etc at a set weight then the suggestion has always been that that’s it. Fixed at that weight. 

Just as they also stipulated that an aircraft that was over 600 or 760 kg could not be artificially lowered, by throwing out seats, lowering tank size etc etc. 

Doesn't GA want all the parts made for aviation "type approved",

 

If the builder of an aircraft makes their own piece, for their particular type of aircraft. It would be expensive to get that "type approval".

 

Hence we have to have ,

 

Exemptions.

 

spacesailor

 

Nope.  

CASA might.

 But “GA” is such a diverse group that you should not call anything by that epithet. 

Certified aircraft in GA need to have approved parts though they can be made by  and approved by a LAME with appropriate qualifications. 

But GA experimental/Amateur built ( which is more appropriate comparison whenever you mention or think RAAus vs “GA” ) can have parts made by the builder. 

This would be part of the reason they kept him circling for an hour, to get the right people in the tower where he needed them. The other would be to get the fire trucks fuelled up.

 

The audio I listened to was only 29 minutes long from “emergency emergency emergency” call to end of landing roll. I don’t think it was edited.  

This is just another example of how much folly there is in the insistence of medicals for GA pilots. A GA instructor needs a class 1. A hangover from WW2 that should have been thrown out with some sensible process replacing it. It is only good for the time the person has undertaken the medical. As soon as they walk out the door anything can happen and in this case it did. You can bet that CASA will have no comment on this. The fact that there is no demonstrable benefit other than so called public perception won't faze them at all. As with previous similar events they will ignore it and espouse how they and their political masters are keeping us all safe. Makes me want to puke.

 

Not quite kgw.  Instructors/CPLs can now just have a class 2. But only if they are just instructing and/or cargo piloting.

I don’t know whether the instructor in this case had a class 1 or a 2. Cos the reality is that most instructors actually are on their way up the food chain and do charters and other air work when they can so most have a need to keep a class 1. The only instructors with a class 2 will be the older ready to retire type guys who do a bit of instructing for some pocket money etc or to keep their Ma and Pa flight school going ( and we know they are now a rare breed due to all the CASA over-regulation. 

Sadly CASA won’t let this faze them. What’s the bet they use this as argument to ramp up medicals. 

Is it true that the stall speed is not being increased at the same time as the max weight?

 

Are there any aircraft that will satisfy this requirement?  A Lancair will not, but maybe a Cessna will.

 

Seems to me like a clayton's deregulation...  the deregulation you have when you are not having a deregulation.

 

I have never really seen any loosening of any regulation by CASA which didn’t come with some strings attached which negated much of the lauded change. 

Too much jumping from indicated  to TAS here. Even in same sentence comparing indicated speeds of one engine  to TAS speeds of the other. 

 

 Ball park figures when you compare  the same category of speed ( TAS or Indicated) is actually so close that it would be pointless spending so much more money for the 915 to achieve very little. 

 

How do they deal with the increased VNE?

 

Can’t remember. But empirically speaking VNE is airframe stress related so I suspect it just remains the same. 

I was only comparing the jab to Seminole in terms of geometry in an engine out situation.

 

Low performance twins only exist to train pilots.

 

The cruise performance gain of the Seminole's 2x180hp  engines over the aircraft it was developed from the Arrow 180hp is only about 30 knots for all that extra cost. The Seminole's single engine ceiling is only 4000ft and that's with retract and feathering props, I just think the twin jab would be a total dog on one engine. Don't forget that you are going from  120hp to only 80hp per side

 

The twin jab first flew in 2013?  and only a few video's none showing a stopped prop tells me somthing, sorry to be negative but that's how I see it.

 

I can’t say what it actually flies like as I’ve only seen it static in the jab factory. But Stiffy and Jamie told me it has significant positive flight characteristics on one engine ( figures previously given were what they told me.) and there have been a couple of flying journal articles by independent authors about the South African one and they reflected similar positive characteristics. 

Can’t say anything about a Seminole characteristics but I’d have to say that given it is nothing at all like a twin jab ( except it flies and has 2 engines) that the comparison is probably not valid. 

The close spacing of the engines would help but it won't be fool proof, relative to the size and length it is not much different to say a piper Seminole. Low performance twins like the Seminole can just maintain about 8000 on one engine. With its 360 total horsepower  and retractable uc it is way slower than a Cirrus with 310 hp. Why reinvent the wheel.   915 in a jab 230 yes it would be a mini cirrus 

 

Mmm. Seminole is not really anything like a twin jab.  But to go with your example. 

I would say the reason to reinvent a wheel if your original wheel is a Seminole is the new wheel is:

half the weight

2m shorter and 2 m narrower

About 1/4 the cost new and probably 1/10 to convert an existing owned 430/230

I can take the 430/230 that’s in my hangar and turn it into the twin myself. ( ok -once it becomes available) 

Can take off and land in half the distance.  

Has less payload but as it is I rarely fly with more than two people on board. That’s all I need.  

Use it for a really cheap twin endorsement

Why it over a cirrus?

all the above again but some numbers vary a bit for the cirrus 

Has two engines rather than an engine and a parachute ( though I agree there’s times a chute would be preferable. )

but its horses for courses. But to say something exists therefore don’t invent something different is a bit self defeating.