dlegg

This is a copy of a blog from a pilot in the USA who flys a lot and puts a lot of hrs on a Jab 3300. He is currently on his second 3300, 900 hrs on the first, 600 on the 2nd. He bought a FWF kit from Jab USA and this is his thoughts. Having flown my Zodiac XL about 600 hours with my Jabiru 3300 and Bing carburetor I must say it has had it good points and bad. The short story is that initially the performance I got was quite poor. With some minor changes, performance improved to the point where it seemed acceptable. However problems remain which are perhaps serious. Now the longer story... First, in defense of Jabiru and the Bing I will say that the firewall forward kit I got with the engine did not properly address installation in the Zodiac. Essentially the kit seemed to encourage installation techniques that produced bad results and were in direct conflict with the installation recommendations in the Jabiru engine installation manual. Note too that the manual itself has improved over time. The most recently released manual (dated August 2009) is the best yet. To make matters worse, when I built my airplane I was new to the entire process, so I hired a certified A/P to install my engine. He did a mostly reasonable job but actually did not read the installation manual. I assumed he knew what he was doing. I have learned: hay, it’s your life, read the manual no matter who is on the job. The firewall forward kit I got failed to address the following two issues mentioned in the installation manual: 1) Do not connect scat tube directly to the carburetor. 2) Avoid a 90 degree bend from the side in the intake tube coming into the carburetor. In addition, I have learned though independent study and personal experience that scat tube in general offers significant turbulence and drag in the intake system, especially when bent. If you choose to use it, use as little as possible and avoid sharp turns. I no longer have any scat tube in my cold air intake system. I almost never use my carburetor heat system so I am not worried about scat tube in that system. In your climate, perhaps you need carburetor heat, in my climate I don’t. With my initial setup, which had scat tube everywhere, I found that the engine ran very rich at higher throttle settings. At full throttle the engine burned about 13 GPH – not exactly what I was expecting! Also at 10,000 feet the engine ran so rich that it shook the airplane badly at full throttle. I knew something was wrong so I started looking into it. I learned that air does not like to turn corners. Because the air traveling along the outside of the bend has further to go than the air traveling along the inside of the bend, turbulence results. Scat tube is not smooth, especially when bent. The uneven walls of the scat tube create drag and turbulence. Inducing turbulence right at the carburetor intake creates problems, especially for the Bing carburetor which as sense ports at its opening. I have read that A 90 degree bend in an intake system produce drag that is roughly equivalent to 3 feet of straight tube. Because of the way my intake system was put together, when I computed the total effective length of the tube in my cold air intake system it came out to about 12 feet! What a mess. No wonder the engine was performing badly. My cold air intake system now uses only radiator hose. The hose is as short as possible with as few bends as I could manage without a complete re-work of the system. Simply eliminating all scat tube and replacing it with radiator hose eliminated the high fuel consumption and added a very noticeable amount of power – it was not subtle. However a new problem showed up. At wide open throttle the EGTs were very uneven. To help reduce this problem I added a piece of aluminum inside the radiator hose running from the air box to the carburetor. The aluminum is centered in the hose, is vertical and is bent such that it runs down the center of the hose as it makes the 90 bend. This helps the air make the corner, reduces turbulence and has evened out the EGTs a bit. All these modifications were made about 550 hours ago. EGT temperatures are still not as even as I would like and vary considerably with throttle and altitude. Different cylinders are hotter than others depending on throttle setting. On some days when I fly at about 1,800 feet MSL and have a certain throttle setting at least half of the EGTs get too hot. It is necessary to change altitude or throttle setting. About 150 hours ago I re-pitched my prop to make it steeper. That lowered my engine RPM by about 100 RPM. That has helped keep this annoyance to a minimum but it is still there. I have noticed that on my engine it is the back cylinders which seem to have high EGTs. I have always suspected that this is because their intake runners connect to the intake manifold on the extreme left and right. The Bing’s main jet is in the middle and the Jabiru’s intake manifold is quite small so mixture is unevenly distributed to the cylinders. The two rear cylinders run lean as a result. Just a theory mind you… About 80 hours ago I found a burned exhaust valve on my number 5 cylinder. It was easy to replace but got me to thinking. Perhaps that cylinder has been running too lean. More recently oil consumption has been going way up. The engine now burns about a quart every 4 hours. When I replaced the burned valve I notice some scoring in the cylinder wall. I am not sure but at this point I am suspecting broken rings on #5 which might explain where the oil is going. In the next day or so I am going to run another compression check with the hope of learning what is wrong and where the oil might be going. So, is it possible that in 600 hours with un-even EGTs with the tendency for the rear cylinders to run lean I have shortened the life of my engine? I don’t know – I am just wondering… I have been considering one or more modifications. 1) Redesigning the air intake to eliminate the 90 degree bend from the side. This would be done with a custom air box intake system to replace the radiator hose. 2) Replacing the Bing carburetor with a Rotec TBI-40. In summery one of the Bing’s strengths is also one of its weaknesses: the lack of a mixture control. I like the simplicity. I don’t like the lack of control. I am attracted to the Rotec TBI-40 because of the claim that EGTs are more even. I am not looking forward to re-running my throttle cable, turning my coke cable into a primer cable and adding a mixture control. On the other hand I can’t say I am thrilled at the prospect of an early engine overhaul either. I wish I had more information…

Renewal sent in 20/7. Expired 6/8. 15/8 receive notice that rego is expired/overdue........ Call to be told to disregard expiry notice as is computer generated.......rego's taking 5 weeks to process. So why not get the computer to process the rego instead of obvious expiry notice's and make everyone happier?

I disconnected jab airbox inlet entirely and test flew without anything attached to carby inlet and could not believe watching CHT's all average 120c(normally 150c or above) and all EGT's nearly the same as well. I would like to try just a pod filter but lack of room prevents this. Is the standard Jab airbox too restrictive?

Looked at the pricing of the clarity aloft sets, and can't for the life of me justify over $600 for a piece of wire, mic and a couple of in ear speakers with a bit of foam around them. Must cost them 25 bucks to build. Compare prices to a good quality sennheiser, bose etc and mad not to pay a bit extra............

"The AN requires that two inspections be done after assembly. As far as I know this is standard practice in signing off a construction or initial assembly. If the control systems have not been altered since original assembly they should not need inspecting now. Surely?" So, the million dollar question is are all 19 reg planes grounded until a duplicate inspection has been completed, regardless? Or only after next maintenance or adjustment? The way that I read the AN I would say not grounded........... Date: 8 th August 2014 RECREATIONAL AIRCRAFT AIRWORTHINESS NOTICE AIRWORTHINESS NOTICE IDENTIFICATION NUMBER: 08082014 rev1 To: All owners and operators of 19 AMATEUR BUILT and 95.10 aircraft operators. Background: The RA -Aus Technical Manual Section 4.0 – para10 states: CRITICAL MAINTENANCE. RA-Aus defect and incident reports indicate that engine controls, engine accessories, propellers and flight controls deserve special maintenance attention. These components and systems should all be secured by positive safety devices and should be checked by an independent person after any maintenance. Recent investigations have identified potential areas of concern relating to the integrity of primary flight controls and with concerns that these areas are not being addressed. As a result Recreational Aviation Australia Inc. has mandated this airworthiness notice. Action Required: Mandatory Duplicate Inspection requirement before next flight: 1 Inspections required: 1.1 Following assembly of an aircraft and prior to flight, two inspections of the primary flying control system shall be made to ensure correct assembly and operation. 1.2 Following adjustment, overhaul, repair or replacement of any part of the primary flying control system of an aircraft, two inspections of affected systems shall be made prior to next flight to ensure correct assembly and operation. 1.3 "Correct Assembly and Operation" means that the primary flight control systems and all components and parts have been correctly assembled and adjusted and that locking devices are made safe in accordance with approved procedures and accepted practices. Additionally, inspection should confirm that the controls have full and free movement in the correct sense throughout the specified operating range. 1.4 Each aircraft inspection shall be performed and certified by two individuals that must hold one of the following accreditations: A Recreational Aviation L1Pilot Certificate or L2 Maintenance Privilege or Licensed Aircraft Maintenance Engineer. One of the inspectors may have been involved in carrying out the work but at least one of the inspectors must have been independent of the work. 1.5 During the inspections specified in this Airworthiness Notice, care should be exercised to ensure no loose objects which could subsequently affect the operation of the primary flight control system and the safety of the aircraft remain unaccounted for or uncontained in the aircraft structure. Reports and Recording. 2 On completion of the inspections if any issues are identified, a Recreational Aviation Australia incident report is to be completed and sent to the Technical Manager. On completion of the inspection, if nil defects are evident, a statement to that effect is to be recorded in the aircrafts airframe log book citing 0882014 rev1. Darren Barnfield Technical Manager Defect Reporting is one of the primary ways we have in ensuring continued safety in our operations.

Just gotta love this: "Watch this" says the salesman/instructor as he puts the cirrus into a spin........ Aviation safety investigations & reports Loss of control involving a Cirrus SR22, N802DK, near Katoomba, NSW on 10 May 2014 Investigation number: AO-2014-083 Investigation status: Completed Summary On 10 May 2014, an accredited Cirrus salesman conducted a sales demonstration flight of a Cirrus SR22 aircraft, registered N802DK, in the local training area, from Bankstown Airport, New South Wales, with a pilot (and potential aircraft buyer) seated in the front left seat and one passenger on board. At about 1330 Eastern Standard Time, the aircraft departed Bankstown and the salesman, as pilot in command (PIC) elected to track towards Katoomba at about 6,000 ft above mean sea level. After demonstrating a series of turns and a straight and level stall, the PIC selected 50% flap, rolled the aircraft into a left turn at about 25° angle of bank, reduced the power to idle, and raised the nose of the aircraft. The right wing dropped rapidly and the aircraft entered a spin to the right. When about 2,000 ft above ground level, the PIC was unsure whether he then had enough height remaining to recover control of the aircraft, and elected to deploy the aircraft’s parachute. The rocket fired, the aircraft initially pitched up slightly and then as the parachute deployed, the aircraft pitched down rapidly into a nose low attitude. About 6 seconds after the rocket fired, the right snub line of the parachute released, followed by the left snub line, which then established the aircraft in a wings level attitude. The aircraft narrowly avoided powerlines, collided with branches of a tree, and came to rest on a fence in the garden of a residential dwelling. This incident provides a reminder to pilots to know your own limitations and those of the aircraft.

A new avgas bowser setup is currently being built, due to be operational in September. None available till then. Warwick is not normally busy during the week, but can have a bit of extra glider ops on the weekend. No landing fees and everyone is welcome.

So, what are the requirements for an experimental aircraft registered VH to enter CTA? Would I be right in assuming that I could convert to a RPL with CTA endorsement, re-register my home built 19 as VH, fit a transponder and then legally enter controlled airspace/aerodromes? Does the maintenance privileges also carry over if you are the builder? Now theres an opportunity to get up to some mischief........

What are you hoping that it will look like when finished?

Both organisations are good and cater to different groups. Do you have a PPL or intend to get one, intend to register your homebuilt as VH, would like to build an aircraft with a larger MTOW than 600kg?Then SAAA is the only way forward for you. If you build a plane that fits in the RAA sport category, 19 reg, 600kg MTOW, stall speed lower than 45kts, day VFR only, RAA pilot certificate, then RAA is the way forward for you. Both organisations have rules to follow, so you really have to decide which way you want to go before you start. Both websites have plenty of information to wade through. www.raa.asn.au www.saaa.com

Can anyone provide a basic summary of how to go about changing a RAA 19 reg to VH reg? If you have already built your own plane, changing over rego, getting the RPL and a CTA endorsement would really open up the country.

Reckon Matt Hall could just about throw a leg over your model, hang on and go for a ride:plane:

Looks great, very inspiring, I might start with the SDS injection and go from there:chuffed:

Hi there Avocet, I'm keen to hear how the injected, liquid cooled head jab 3300 is performing. I think you could be on a winner there. What sort of prop and pitch etc?

Now that I'm flying and able to get about to different fly-ins, looking to camp overnight, am after suggestions as to what essentials to carry on my plane. With a low wing I expect a tarp of some kind to put over the wing and a sleeping bag and mattress for under. Question being, how light weight to go without sacrificing too much comfort, and not letting nasties in overnight. Cheers

I see this is an old thread with no answers but is there such a site now for avgas prices, or would members like to let us know their local price currently and location?

I have installed an MGL Avionics Voyager system with syn vision. It is remarkably accurate in its detail, shows hills, ranges around my area as a direct copy of what is seen out the canopy. The Efis unit also runs the autopilot, will fly routes with as many way points as you like, can use vector or raster maps etc. Fine piece of kit.

Is there a CTAF set up for the weekend, or just 121.2?

Well done Marty, when you see a major component done its time to crack a beer and reflect, dream of flying....... Enjoy building while you can, but you are working yourself out of a job:thumb up:

I am quite happy for negative attitude people to take their ball home from the sandpit, who needs them?

Absolutely positively use mine religiously, for the last 15 yrs, nothing goes into the tanks except thru the mr funnel, but, I must confess, it has never needed cleaning, nor has it picked up any water, all with mogas. So, do I really need it:blink:

Sadly, more happens on internet forums than real life. Engine promises over 2 years late, now an aircraft apparichian.........buyer beware.......I know this Ghananian bloke .......

Ride on mower tyres look great, however get a serious vibration going with a small bit of speed (thruster speed) just ask me how I know...........

I dunno, just my view, but I think it is just a generational thing with young adults now growing up with computers, gaming etc. Older ultralight type aircraft, which there are really a lot of around and quite cheap to buy, simply don't rate with this generation. Not fast enough, too much trouble to learn in, ancient technology(apparently). Hell, these kids don't even want a push bike any more. I tried to get my son interested, he enjoyed the actual flying, but bailed out when he perceived the work load of studying the BAK and nav, met etc as "uncool and over the top Dad" Can't I just fly the thing? Maintenance, preflight, commonsense, WTF? And travel to the airstrip.....I enjoy the country drive......it's just a chore for these young adults, looking at there smart phones all the way. The magic of flight just doesn't have the same impact as in my generation. They just don't seem able to smell the roses anymore............

Technical information Resistor Spark Plugs Resistor type spark plug’s incorporate an internal resistor to suppress ignition noise generated during sparking. The ignition noise which is often known as either electromagnetic interference (EMI) or radio frequency interference (RFI) can disrupt electronic communication signals, effecting the performance of sound systems, cellular phones, two-way radios and even engine management systems. As EMI or RFI can also cause premature failure to other electronic components in a modern vehicle, it is important that resistor spark plugs are used to prevent this possibility. Put simply, when a spark is formed it creates a mini-earthquake in the electronic world; the internal resistor in a spark plug filters out the noise created that may affect electrical components I was getting interference on my microair radio with D9EA plugs so tried these. All noise went away:oh yeah: