jetboy

They just ran this story on TV3 lately and the pilot stated they topped the fuel up prior to departure for 2 hrs20 by dipping tank and measured fuel and they had completed 1.5hrs when it faltered. mind you something else doesnt add up as they obtained "$20 worth" to depart which at todays $2.01 / litre for 91 octane would not be much flight time allowing reserves and unuseables? Ralph

The pressure switch for fill cutoff on washing machines should do. No I dont use one, have a hourmeter connected to oil pressure switch. Technically this is not correct for engine hours, as a proper tacho records revolutions and displays the result as hours based on 75% power rpm, which is a better representation of engine wear. Just thought you'd like to know. Most people put in the logbook the figure they want (a) to boast about (b) pay for overhauls on. Ralph

the storch uses a little inline pump in the belly of the aircraft I had a look at the club one yesterday there is an inline tap and receptacle external, and they just clip a short hose down into plastic cans and turn the pump on and walk away (not sure if this is a safety measure or to pass the time) They actually fitted a different pump there for some reason I dont know if its better. I'm also curious as whether the fuel tap is essential or backup like if it gets knocked on in flight does that drain your fuel? If I was to copy this idea I'd prefer a shutting off type release coupling. Mr Storchy can you enlighten us? The facet style pumps do take time but so does the siphon and funnel act which I had to do again today and I think the built in Storch system is relatively safer. I can handle 10 L direct pour from my ladder but 20L too difficult and too heavy to rest on the funnel as that would badly load the tank $$$ the siphon works fine just always do this outside and not too windy day. Agree the proper hand pump is best but getting 2 60L or a 220L drum out to the field and off the vehicle is another mission. Ralph

i've tried a few ways including an electric pump which tended to get more fuel outside than in. The deluxe way would be a vehicle mounted mini refuelling station with nozzle and the car parts outlets have a (cheap plastic) version of this I have not tried yet. EAA magazine used to feature them in the adverts section. I now use 20L plastic cans plus a couple of 10L. For the 20L I sit them on a foam rubber pad over the wingspar area and drop a siphon hose in. While thats going on I use a Mr. funnel on the other side with the 10L containers and the residual from the 20L that doesnt drain. It takes practice to avoid overfilling this is where a conventional nozzle would be graet. Just pumping up via an open hose is a problem as there is residual fuel to handle as well. Allways prefer airfield fuel stations because there is some hassle in transporting the cans around too, but for now I have to do it manually. The static is generated proportional to fuel flow & velocity, so I havent done anything special to the containers, one method is to fit a throughbolt with metal brazing rod down into the container, for earthing, but you'd need to do this for every container ever used to be sure it would make a difference. Probably more risk filling the containers in the first place. Ralph

The mod done to quite a few 2200 in non Jabiru airframes is like this: http://www.geocities.com/cffd66/Airplane/Jabinstall/Airbox.html I have tried different systems to achieve proper carb tuning, including cobra head, smooth bore rubber tubing etc. With the cobra, rotating the assembly on the carb clamp made a difference as the inlet tube was offset to one side, making repeatable results difficult. Putting the vanes in the intake at the carb was best. I only had to do this with the original "ultra lean dont worry we know what we're doing" kit but what that did achieve was to show me that my original intake was not optimum. Ralph

I doubt the vibration wiould wear in although I did see some wear on my needle / jet when last changed out for the revised economy tuning. When you say full lean / full power do you really mean that? Should be leanest at around 2900 and richest at full power, not like the original jetting which was opposite. So there is a possibility that with the prop load you have it is over rich or excessively lean at these settings, but more likely the air is uneven going into the carb, needing a cobra head and/ or straightener vanes. I'm posting a picture of these on the thread about this Ralph

The Jabiru prop had no noticable vibration and was fitted new and run for 230 hrs with no damage no repairs black strip still intact with slight rain erosion and never run loose - just cleaned bugs off. I pulled it because the 701 needed a different prop to run properly. I was about to fix the pitch differential and the tracking was out of tolerance also, both these errors could not be taken out by bolt torqing alone and I'd be reluctant to buy another for those reasons - I keep it as a spare. Its remotely possible that the pitch imbalance could have resulted in the poor performance, but I needed the extra diameter. I could see the difference between blades when flying with the sun behind - the lines were wobbly and divergent. New prop is by Brent Thompson and casts one sweeping curve - whatever that means it looks much sweeter to me. Engine is smooth as normal - both props showed some engine rocking around 1200 rpm, way less than a friends SK with new prop which i thought was so bad it was going to shake something off (actually it did - sheared his oil cooler rivets) he took it to a GA balancing place and they said it was OK - .09 IPS or something well I'm pleased he got a 2nd opinion but I won't be flying in it Ralph

A neat way to measure the pitch difference is by holding a laser pointer across the back of the blade at approx. 75% length so the beam shines on the floor. move next blade to same position and check beam shift on floor. I got 1" difference which equates to about 1.5 deg on a stock Jabiru prop (which is no longer in use) Ralph

Teenie, I read your original post again and if it seems your setup without fuel pumps etc. is satisfactory from a fuel flow situation (supplies 150% of engine requirements through the float valve with airframe tilted in max climb attitude) and your only worried about vapour lock, perhaps a check of the routing of the fuel system and components would help. I was told by an AACA build inspector once that fuel should flow down to the lowest part of the system, where the gascolator and/ or lowest drain is located, thenceforth the fuel must only flow upwards to the carburettor. He commented on this because my C150 at the time had a fuel hose running up from the gascolator , over an engine mount and down to the carb. Apparently this setup would have not been allowed on a homebuilt plane. This does seem to make sense to me, in that if vapour or air gets in the hoop of fuel line the head of pressure is effectively less to the carb. The Cessna used to falter on the first flight after maintenance, where they had cleaned the gascolator for me, and I learnt to cope with this by shaking the thing up a bit in flight. Later on I trained them to leave the gascolator alone, it was a glass one so if it aint dirty dont fix it. In dealing to and with microlights I've also tried to avoid excessive use fuel filters (like a chain only as good as the weakest link) and those rubber squeeze pumps, some of them have had the check valve or bits of rubber come adrift inside and block the outlet. Ralph

Yep 75% power is not the rpm shown on the engine spec charts, with a prop load its entirely different. when I changed my prop the cruise spot for same airspeed, fuel flow and EGT moved from 2900 to 3050 rpm, 250 rpm off full power. The Continental 0-200 manual has a useful table showing HP vs rpm and fuel flow for a propellor load. The difference between 100 hp and 75 hp is 200 rpm, that is 2750 - 2550 rpm, and thats how mine flew too. (after fitting new cyls and getting the timing and prop right) Ralph

we've had a Hapi VW that has the magnets in the flywheel end and a stator coils putting out 10 amps or so. Very similar to Jabiru. Most motorbikes have them? This particular one cracked the flywheel and was replaced with a belt/pulley mounted there and a dynamo from the John Deere / Kubota parts dept. and it works OK. B+C in the US sell a similar alternator, about 8 amps worth. As your electric requirement is less, it is feasable to make your own. I made a unit from a stepper motor ex old computer equipment. connected the wires to 2 sets of bridge rectifier diodes you can tell which windings do what by shorting them and turning the shaft. Got about 1 amp from this one it was 3" dia. I get a lot more out of a DC drive motor from an ancient mainframe computer printer (these are the ones that would take your arm off if you get in the way, DEC LA-120) Most fuel pumps wont need a regulator Ralph

Mark, You first need to establish whether you want round hole mounting or GA rack mount is acceptable (or indeed handheld radio mounted on the panel). The amount of power output is not a problem especially if using ultralight style engines - unshielded ignition reduces your receiving range so that a 1.5 watt transmitter is plenty. the problem with the handhedls is difficulty of operating the small controls, and messy installation, non-standard headset connections. I seldom recommend them for mounted use but my favourite is the Icom a20 which was still big enough to use, with controls limited to 2 faces. In NZ practically every recent round hole radio except the Bekers have been troublesome - some seriously so and a few have been dumped despite the extra features these newer designs have. Cant buy them from the dealer anymore they have been so bad they gave up. Another unresolved issue is that both of the Aussie radios, nice as they are, make for very noisy transmissions in a typical microlight, because the pilot and copilot mics are both live turing transmission from either ptt. Yes this has been represented to them so you might see a software change in the model you buy today but that leaves the rest of them needing a fix. Of the remaining group - the traditional GA rack style, I've only heard good things about Garmin SL40, the Icom a200 and its cousin in design Bendixking KY97a. There are a few apparently good cheaper options by Filser and ValCom. I've had a long association with the a200 and KY97a models and from an installers and techs point of view they are the best. Only faults I've seen are misalligned coax connector on tray and internal fuse DROPPED out of holder, both on the same A/C that had recent damage history so I dont blame the radio there. You have probably figured by now that the savy money would go on the Icom A210; just hope it is as good as its predecessors. The best intercom is PS engineering but you wont need one with most of these radios that have it built in. Ralph

From memory the A20 runs with an electret mic or possibly amplified electret - not the GA mic standard. They run OK with the audio from an intercom coupled via a capacitor and around 5 Kohms resistor for the ptt grounding. You may need to do some work on the Altronics headset there has been a number over here struck trouble with squeals such as RF getting into the headset and I havent had one on the operating table yet to determine the cause or whether it is limited to that brand headsets or problems with particular radios. Ralph

Anyone know when the latest Jabachat will be downloadable? I have been trying on various PCs since last week but it doesnt work Thanks, Ralph

Hi James, I think a lot of popularity is due to what engine is supplied or recommended by the kit supplier - and some suppliers are "agents" for certain engines too. And reliability history once an engine type has become established helps spread the word (or not). The difficult question is what about the newer entrants - ULpower and Rotormax for instance. You have to decide what limitations and features are tolerable to achieve the power / weight demands of the particular installation. Geared engines can deliver good power but usually need liquid cooling and multiple carbs to do that. Earlier Hirths got a poor reputation and with Rotax ramping down 2 stroke production there is only the Siminoni that looks a possibility, theres just so few around here that its impossible to know if they are OK. Direct drive has limitations as to prop types and rpm (power) useable, but the simplicity of installation and ease of maintenance helps. In some countries the manufacturers recommentations are mandatory and that means a Rotax 2 stoke has major work and crank replacement every 300 hrs. This sort of policy really distorts the market because some makers publish proper service bulletin data some dont (bother to publish any) Apologies for not being able to answer the question - leave your engine choice as late as possible we will all know a lot more about whats best then. Ralph

That B10J was the inspiration for me to get the JFS100, I saw it at Oshkosh over 10 years back. I dont think hes flying it lately he got it approved by the FAA as a pt.103 ultralight because the thrust was no more than the 30 hp power previously used - around 85 lbs thrust. I still have the info on the machine its a converted Mitchelwing B10 and goes about 45 mph for 45 mins on 45 liters of kerosine or whatever will burn. A thrust attenuator clamshell was fitted aft of the nozzle to make for steeper approaches because flight idle is still around 60,000 rpm and there is no prop drag as per the original. The JFS100 gas generator section weighs about 55 lbs If left as a complete turboprop it puts out 90 hp at 3,000 rpm. Now we're talking..... Ralph

Just download the latest Jabiru SB its got enough info to get the tuning right for the Corvair and you could probably use their taper needle too. Its the carb of choice for Rotax and I've had no troubles on the 2200a - I would prefer not to rely on the rubber diapragm for the CV operation where my Keihin from Honda H1300 cars does not and the needle has the possibility of dropping down or wearing against the needle jet - but overall these items are likely to be OK for the first life of the engine. If it doesnt work out then the Aerocarb will do. Ralph

Have you replaced the viton tipped float needle valves ? These loose their ability to shut off the float fuel supply from the engine suction pump at high rpms, due to fuels attacking the rubber. They are very hard to check visually. New ones look the same but work properly. If you have this problem, a ground run at high power with observer might see fuel coming out the plastic overflow tubes. But the EGT usually just gets low and engine " bogs down" with overrich mixture. If your EGT is dropping straight to zero, might be a blockage in the float or jets. Ralph

The 601XL was developed specifically with the 3300 as the original powerplant, although Zenair are happy to supply a 912S these days. Production aircraft have the Continental 0-200. Another auto conversion is the Great Plains liquid cooled geared VWs Because the Jabiru is local youll probably get best cost ratio and it is the best fit overall, my 2nd choice would be a timex. 0-200 just buy new cyl. kits and mags and youre good to go Ralph

Hi t87 you forgot to mention nylock nuts I would be worried about using S/steel bands instead of nylon ties to bunch wires and ducts and hoses from chaffing each other but I plead ignorance here I've not seen those things anywhere in fact none of the items you highlighted to use were present in my 1961 Cessna 150 engine bay I leave it to wiser men to consider whats best in the UL scene be careful out there Ralph

To find out if its DC power affecting the radio try running it just on battery and see if the noise is gone. The Powermate is a good regulator so should be OK. If the noise is coming in the aerial things get a lot harder to fix, may need to put aerial under a wingtip or somewhere far away from the ignition side of the 447 Ralph

To have everything working correctly you are supposed to use the same type of thermocouple leads, right back to the gauge. Extensions are sold for the job. In the real world its OK to use wire joiners or crimp connectors onto normal aircraft wiring to get the extension you require, If you can put the join in an area of same ambient temperature as the gauge is that would be best. The error you will get is an under reporting of EGT by the temperature at the joint. For CHT this could be significant but EGT on direct reading gauges wont be noticed. It can be difficult to solder the leads, they are metals like nickel, chromel , alumel, constantan. yo can braze them with Easyflow rod if youre determined. I used a joiner block of the type that has a metal strip between the screws and the wire being clamped, to avoid shearing off of the wire. Ralph

In considering the revetec I favour a couple of other new designs: (because I'm still waiting to see a Dynacam or Zoche that goes anywhere on a plane) http://www.dair.co.uk/ and http://www.masschimotors.com/ of course we still have to wait till they exist in production and are competitive for both cost and reliability. Ralph

As Dieselten points out, another dead end http://world.honda.com/news/2003/c030304.html I think he's a bit harsh on Wankel Rotary's though, there have been at least 2 manufacturers that have flown certified ones - Curtis-Wright ? and Diamond/Midwest , as well as a few perenials that turn up at Oshkosh - but as you still cant buy one yet, they dont count Ralph

Flyer I wouldnt be too hasty about electronic control, it just cuts reliability. The UL260 is limited to 20 mins or so with alternator failure and another good example is the Diamond DA-40 that crashed with double engine failure due to a bump in the power supply when they selected gear up - the ECU's momentarily stopped working. Theres very little in fuel efficiency because aircraft engines only need to operate around a 10% rev range most of the time and a carb or mechanical fuel injection and fixed timing is just as good. Just select the hp / weight / price combination you require and fit a solenoid to that starting enrichment control ( I must relable mine, "choke" is not what it is) that will turn a 3300 into FADEC control. Ralph