pylon500

Just out of interest, what sort of problems did you come across when working at Subaru on the EG-33 engine?I have one, still in the original car!And I would never take it out to put in a plane, the car is too good! Arthur.

Chasing info on gliders and found this...http://www.boonahgliding.com.au/subaroo.htmCan't seem to get my links active?Arthur.

I'm running an INVERTED 582 and used to run on unleaded mogas.I

was fortunate that I was rebuilding my plane during the time of the

fuel adulteration problems but did find the odd problems starting and

often had fouled plugs running ULP.Combine this with using

Avgas at one of the Nat-flys and on the way home I started getting some

overheating and what sounded like detonation!?On landing at Bathurst to refuel my plugs were completely fouled, so after refuelling with ULP and some new plugs I got home OK.I now run PULP (Caltex 98 if possible) and my motor runs like a clock.I have only used Castrol Super TT, and now use it's replacement Active 2-T, I may try a synthetic one day.Arthur.

On something like a Thruster, I tend to feel the extra power is absorbed by the extra weight incured by fitting a 582.If

you fit a 582 you usually also want to fit electric start, a battery, a

couple more instruments, a 'C' box and probably a three blade composite

prop.Not everyone also wants to fit oil injection!It

can also have some weight and balance effects, I once tried to instruct

in a Thruster fitted with a 582 and it flew like a dog!Better to keep light, and save money. Tony could probably give a better insight.Arthur.

In our field of aviation (low cost and light weight) I would have thought the heavier more expensive (and harder to find) square tube wouldn't stand much chance.I

tend to look more from a production point of view sometimes, and had

thought of square tube, but I would have to use enough of it to make it

worth while.I'm still thinking.....Arthur.

As a former RAAF 'Aerostructures' repairer with a bit of

background in bonded structures, be prepared to pay lots of money for

not only the exotic epoxies, but the infrastructure that goes with them;Freezers,Vac bag systems,Autoclaving systems,Cleansuits,Etch chemicals.That's not to say it's impossible, but a purely bonded Primary structure means you have to be real sure that it all sticks together.The main problem with bonding aluminum (or any metal)

is that you need to create some form of textured surface for the

adhesive to hang onto, many think that bonding is like that trick where

you can hold two polished surfaces together with a drop of water.Unfortunately this has no shear load ability, and this is the most typical load requirement in aerostructures.Many of the repairs I do, stem from the use of slightly acidic (or alcalinic) epoxies to help etch at the bond site.This

can work for a while, but eventually heat and flexing movement will

allow moisture to enter the join and combine with acid residues to

attack at the bond surface.In a recent example a Cessna 182 of about the 70's era (that's a later one!!) turned up with bulging at the ribs on the leading edges.The early (50's & 60's)

Cessnas' had rivetted ribs in the leading edges, the later ones are

bonded for a quicker and better finish, but this one had de-bonded most

of the ribs and started to corrode the leading edge skins.Remember, I'm talking here about primary structures, you really need to say where you want to go bonding stuff....There are lots of discussions about this sort of thing on a really good homebuilders site in the US;goto http://www.homebuiltairplanes.com/forums/Arthur.

All basically makes sense, the Clark Y has turned out to be a

fairly good compromise all round, although your reason for using it ie;

simple to built, is actually limiting you a little.When building a wing, we often like to set it up on a table to get it square (or block up the trailing edge for washout)

but when you think about it, we only support it on the spars, therefore

the flat bottom on the leading edge ribs is not required mechanically

and is detrimental to aerodynamic preformance at speed.Basically

at higher speeds when the camber line starts to dictate a low or even

negative angle of attack on the chord line, you start to get flow

separation under the wing causing drag.If you go to a Clark

YH with a raised leading edge profile, you get better top speed PLUS

you can end up with a more docile stall.From what you've

posted maybe you want to build a metal version of Mike Arnolds AR-5,

maybe have a look at some of the Davis series of lightplanes (DA-8,DA-9 and on)Arthur.ps, Try to keep all your posts in the one thread, the administrator may relocate this with your original post if you pm him.

Do you have a scanner or cad package that you can upload a three view drawing of your idea?Some thoughts;I was getting 70 kt cruise from a 503 in a large, strutted, highwing, all aluminium 'Bird-Dog' lookalike (see my avatar)I keep my VNE to 85 kts 'cause I've never done any calculations for it!My stall is around 32 clean at idle, but with flap and power, I can maintain level flight at 27 kts!What I'm saying is...Aim higher!!Free Lift? Remember, lift is generated on the TOP of a wing, you'll get more lift with the airflow over the top.Why should your firewall create drag?If you cowl the engine and round off corners at the exits, drag should be minimal.To cut down on some of your start point research, have a look at some plans of other similar layouts and improve from there.Try the Hummel Bird.Feel free to pinch some structural ideas from;http://www.pbase.com/pylon500/rootArthur.I still can't get some of the HTML to work!? :-(

If you think we've got the bandwidth, I'll upload most of my building histories!Meanwhile, I've added some more photos to my Yahoo LR-2 site.Arthur.

No, Just a couple of cans of Baked Beans, and WATCH OUT!

I'm into building and I've found some sites to host photo albums Building my 'STOLLITE' here;http://www.pbase.com/pylon500/rootAnd my new project, the 'LR-2' here;http://au.pg.photos.yahoo.com/ph/pylon500/my_photos

Arthur.

Cable update;While manouvering our aircraft into the

hangar the other night, a loud bang was heard which we thought was the

tailwheel turning.We then noticed one of the tail wires

appeared loose, and on inspection found the cable swage had corroded

away under it's heat shrink cover!After all heat shrink was removed, it was found this wire was the only one with an aluminium swage?New cable with propper nickel plated copper swages fitted.

Arthur.

When terminating (the technical term)cable ends, yes the Nicopress sleeve (usually copper) crushes the loop ends of the cable at a higher strength than the cable itself.To

get a neat fit around the Thimble when using Nicopress, if you have the

standard tool, you should be able to do three squeezes on the ferrule.With

the cable threaded around the thimble and fed back into the ferrule,

arrange to have about one and a half cable diameters protruding from

the ferrule, and the ferrule pushed tightly against the thimble, set

the first swage in the middle.You will notice that the ferrule will 'grow' in length, this helps to tighten the loop.Swage

again near the thimble, leaving a small amount of the ferrule

protruding, to both tighten the loop and leave a tapered oppening for

the cables to enter the swage (don't pinch on the edge)Finally, swage the remaining amount of ferrule (also not on the edge) to leave about half a cable diameter protruding from the swage.If you have a wide jaw swager, start away from the thimble first, then set near the thimble.Things to consider;NEVER swage at the same place on the ferrule twice.Don't try to swage onto plastic coated cable, if you get a ferrule that fits, you've got the wrong one!Putting heat shrink over a swage is ill advised as it will hold moisture and promote corrosion.For more detail goto;http://bosunsupplies.com/NicopressSwage.cfmOr if you can read German, (some good diagrams);http://www.schmidtler.de/html/ht_technik/seile.htmAs for EYE and FORKends, these should never be set with a Nicopress tool Any

kinks in the swage tube can form a stress raiser and start cracking

strands, use the correct rotary swage tool or full length hydraulic

press swage.(I have seen a system that used full length jaws powered by a pneumatic hammer, it seemed to work once you got the hang of it)End tonights lesson.Arthur.ps, I don't know why I can't use most of the site shortcuts?

Given a choice between using the GSC prop supplied with the aircraft, or a Brolga, I'll take the Brolga!

I figure this is the place to put forward technical/maintenance questions, so herfe goes.This question is aimed at people using Brolga props.Many of you would have read my thread about the cracked Brolga (Ultraprop)hub we had.Prior

to finding the crack, we had begun to notice an annoying vibration we

werew getting at some airspeed/rpm combinations, typically at 60kts

with around 4500 rpm in level flight with our GR-912 LightWing.Initially

we put it down to an unbalanced prop, but it proved to be within

limits, so we then suspected an imbalance between the carbis'.We also looked at timing and gearbox backlash to no avail and ended up doing the GA fix and said "Don't fly at that RPM!"About then we had the prop hub crack and figured problem solved!But

this was not to be, as once the new hub was fitted, and the prop

balanced, we took off, only to have the same vibration come back. We then found that a nearby GR-912 with a Brolga prop was doing the same thing.We

have an 80hp 912 with a three blade prop running 14 blocks, the

vibration does not actually occour at just one rpm, but more at a range

of 'Loads' on the prop.

As mentioned earlier, we can get the vibration anywhere from 60kts and 4500rpm up to 70kts at 5200rpm.If

we had a manifold guage, it may show the vibration occouring at a

certain pressure which would represent the amount of load the engine is

under (a relaxed cruise?)My theory is that when the prop is not under a high load (like climbing or flying fast), some form of resonance is exciting the blade tips and getting a 'tuning fork' effect going which feeds back as a vibration?I would like to hear from others runninng Brolga props, if they have had similar vibrations?From there we can try to determine the actual cause of the vibration and find a way to control it.As

a side note, back in 2002, I was in Germany and had a fly in a Technam

Golf, and although the translations were interesting, when the

instructor pointed to the tacho, which had a yellow arc between 4200

and 4700 rpm, and said "Nein, nein", I got the idea.And

he was right!, after joining circuit I slowly reduced power and as the

engine came down through that rpm range, a very strong vibration ran

through the aircraft before he grabbed the throttle and closed it

quickly!Arthur.

If doing maintenance on GA's, CASA now want to see authorisation via

the manufacturers maintenance manual, or failing suffiscient

information from same, a Reg 35 Engineering Order to justify basically

any work done beyond a grease and oil change.This must then be

signed for by, the guy that did the work, his supervisor, the hanger

maintenance authority holder as well as being signed and approved by

the Reg 35 guy!What CASA doesn't know is that we all get our ideas from AC 43-13! A

one man band maintainer can usually do about 4 hours actual work a day,

the rest of the time is wasted trying to prove that he actually knew

what he was doing, trying to keep his inventory up to date (in case he gets inspected),

getting all his release certificates in order and trying to convince

his customers that it really does take 4 hours of 'work' time to change

eight spark plugs!!

And we wonder why GA is so expensive and dying?!!

Arthur.

I'm not sure sometimes whether to mention something thereby letting everyone (including naysayers) know about it, or just keep quiet and not get noticed.Todays dilemma is props, I like props, I've got a nice collection on my shed wall!My hassle is with certified ultralights that come with a specific prop and you are supposed to stick with it?My

view is that props on aircraft are like tires on cars, they generate

about 20 to 30 percent of the overall range of abilities that can be

displayed by a car or plane.Many argue that the 'manufacturer' knows best, and will supply the optimun prop for the aircraft.Basically this is crap!More than 50 percent of a manufacturers decision as to which prop to fit is driven by cost.All

the prop manufacturers out there are vying to get their item on your

aircraft and I think it should be up to the user of the aircraft to

decide what specific use they have for the aircraft and be able to

choose the prop that suits that need.And if the manufacturer supplies you with a 'lump of wood' because it's cost effective (to him) you should have the option to replace it with your own choice.I started ultralighting with assorted two blade woods, then could afford a three blade wood.It was nice, I could dial up (on the ground) just the pitch I wanted and feel a lot less vibration.Then there was a big panic because an abused version of my three blade wood came apart!By now I could finally afford to go composite and have done a lot of flying behind a very nice French prop.Then with an engine change I needed a bigger prop so bought a local black composite prop which is doing very well.All

this time I have been doing a lot of flying in a 'certified' ultralight

which when fitted with the 'correct' prop has very poor performance.Anyone

out there flying a locally produced, 912 powered machine with a wooden

'stick' can see how much better others are doing when they change to a

more modern prop.How do we go about removing propellors from the certification process?

The fact that they (Skyfox) needed to use sloshing sealer in their fibreglass tanks, says a lot about the quality of their glass work? As

for Randolph 802 versus mogas, our 1983 LightWing had pop riveted alloy

wing tanks with 'ProSeal' on the joints and as a good measure the tanks

were sloshed.About eight years later (I think we changed from using Super to using Unleaded) we suddenly found our fuel filters clogging up with this brownish 'gunge'which was the sloshing compound breaking down (I'll have to get the photo and scan it!)Howard sent us his new glass tanks (unsloshed) and they're still going.Arthur.

G'Day 'Cecil?'The short wing Avid was living near Bellingen last I heard of it.I helped teach the guy who got it off your dad and found it a great little cruiser!A bit cramped, but I'm only 5' 12" I did hear a rumour it was going to be fitted with a 2.2 Jab motor.Can't find my photo of it.

Arthur.

Yes it would be safer to crash into trees in a Caravan than a

drifter, but I'd still want to be sitting in the BACK seat of the

caravan!, you'd be better off in a Lighthwing.Back

in the 70's, the ultralighters over in WA had a good idea and started

calling themselves the 'Super-light' Aviation Association (sic) where the idea was to build ever faster machines while staying somewhere near 95:10!When I first came across ultralights in the late 70's (in WA), the deal seemed to be 'If you want to fly, you have to build it yourself'.This seemed a good way of separating the 'Untalented rich', from the dedicated 'Want to learn and create' types.This was the EAA's basis of the 'Experimental' catagory; learn, design, create and fly.I

guess people are still learning something when they buy their 3 week

quick build RV-?a, and pay someone else to build it, I'm just not sure what they are learning?As

for 720 kgs, I guess if we're forced to stay under 45kt stall, that

should go some way towards maintaining the low inertia concept we

started with, maybe it should go back to 40kts?I learnt to

fly in gliders, the upper end of which can have VNE's of over 160kts,

yet still have stalling speeds below 40kts, it just requires 'educated'

design.Arthur.

As mere Recreational flyers, most of us only fly day VFR (don't we?!) and listen to our radios if we have them.It is rare for us to require any outside help in our day to day flying.As such, previous AUF (RAAus)

policy has been to protect us from the money grabbing private sector

that runs AirServices, by refusing to divulge the operators of

recreational ultralights.It would now appear that

AirServices simply threaten to bill RAAus directly at which point the

bill is forwarded to the certification holder!I don't know

if AirServices is made aware of the reciepient, or how they would go

about enforcing the monetary procurement from RAAus if the the bill has

just 'disappeared' into the 'system'?<br ="k-block-placeholder">"Say again-crackle-crackle- tower, I'm-screech-buzz-altitude at-buzz-crackle-crackle ?"

G'Day Rodger, I hate to shatter your allusions, but I did point out elsewhere that the old SkyFox is really a copy of the American 'Denny' KitFox (the MKII to be exact)Around about the KitFox V, 'SkyStar' (the newer parent company) introduced a tricycle U/C, and called it the Vixen.The mob up at Caloundra saw this and adapted the nosewheel to the SkyFox and called it the Gazzelle. 'SkyStar' got as far as the KitFox VII before going bust againThe EuroFoxis just another copy, of a copy, of a copy, and so on. As you may have guessed, I'm no fan of the Skyfox, especially after having to repair a few of them.You may notice insurers don't like them either, mainly because of the repair costs.For example, a typical accident for a SkyFox (no a Gazzelle) is a ground loop.This could be blamed on the shorter fin and rudder than a Gazzelle, but either way the damage was usually a collapsed U/C (it is a bit weak) a broken prop, some cowl damage and often some cracking back near the fin post.The annoying bit though is that most of the time, the a wingtip hit the ground, and most of the aileron hangers would break off!That would seem bad enough, but if the wing hit hard enough, it could bend one of the spar tubes, and when that happens....You throw, the wing, away! The amount of work required to replace either spar tube was more than the wing was worth!I don't know what you would do now? My other gripes were basic ones like, a cramped cabin, small doors, a hot cabin, having to duck under the wing in flight to see where you were going, always guessing how much fuel was really in the tanks, the leaking hydraulic brakes, the fact you could apply full rudder or full brake, but not at the same time!Other than that, they seemed nicely built, had attractive upholstery and had folding wings!Sorry if I've crushed anyones dreams, but I can only tell it as I see it.C'mon Howie, lets get more Lightwings out there! Arthur."Now where's that fireproof suit?"

I would have to agree that the oil tanks location is questionable. As mentioned in another post, one of our club GR-582's was rebuilt as a GR-912 by the factory, but when it came back, the oil tank was just behind the pilot seat.This seemed OK at the time, it was accessable and with the vents open, the

heat was not really noticed, the main problem was the length of all the plumbing, plus the change of oil level between level flight and when on the ground (it's a taildragger). The next time some work was done at the factory, the tank was moved to the now typical location, and yes, it's easy to spill oil in the cabin and if the cap's not on right it makes a hell of a mess, but worst of all (to me) is that it makes the aeroplane even more nose heavy. I discussed this with Howie once and he was quite happy with having a CofG range of 16 to 23%!Being a modeller and sailplane pilot, I've been used to CofG ranges between 20 to 35% (some laminar sections will happily go to 40%!) Basically the LightWing was designed and set up to be a trainer, being slightly nose heavy and having limited elevator travel, it requires effort to stall the aircraft and is exrtemely hard to spin, tending to just fly out after half a turn (classic spin at idle)The down side to this is some difficulty in doing three point landings at idle or if deadstick (when you really need to for short paddocks!) I'm wandering off thread here a bit but, when our GR-582 came back as a GR-912, it had new undercarriage that was swept forward compared to original, and this was explained as being needed because the engine was heavier? This is interesting as the wing is still in the same place?? The new U/C moved more weight onto the tailwheel and increased the tendancy to groundloop!!I was not happy. It turns out the U/C was actually the gear used on the GA-55 which as well as having a different wing, has it located about 5" further forward relative to the old GR wing.This puts the gear in the right

place for the wing and CofG as well as giving more elevator authority via the longer tail moment.Still, after asking around, I found that most opertaors of GR-912's didn't seem to mind or notice, and some where operating off bituman runways ?!Now after instructing in our GR-912 for a few years, I've got used to it's habits and I'm happy with the way it stays planted on the ground after landing, espcially in stromg winds.It will bite if you let it, but, if it's the only thing you've flown, you get taught to avoid it, and fly on.Sorry about the rant.

Arthur.

Wow Tony,I logged off after reading the first post to compile photos for my reply, now I'm not sure what to say?I've battled with the emotions of where our 'Ultralight' direction is heading for many years.On one hand wanting to keep 'Ultralights'ultralight, but on the other hand wanting get into really high performance 'Superlights' (to use an old Western Australian clubs name)Having come from flying high performance sailplanes, the idea of flying in scouts didn't really appeal to me.But now, looking at obviously lightweight G-A planes on the market, at the price they are, and the type of people they attract (Yeah, it's the green eyed monster!) I feel myself in a dilema; I'm happy to keep our club operating with it's two LightWings, flying aircraft affordable to the Joe in the street, and not push to upgrade to some mega-buck hot rod, just to attract the well heeled to our club. At the same time I'm busily working in my shed to produce a kit for a 503 powered single seater that will hopefully do in excess of 120 kts and some time in the future spawn a 500cc racing class!Any-way, back to the LightWing Mk II question...First a quick history lesson on 'contemporary' LightWings.(I'm not going to spell out the entire Hughes history)Production started with the LW-1, powered by a Rotax 532 (yes, the hand grenade) and was often reffered to as the 'BOX'

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I first thought it was ugly, but after having flown Scouts, Thrusters and Drifters, to fly something that didn't flap and twist all over the place was very assuring. (sorry Tony)Our first LW-1 had rouond tube struts, no doors, a pull start and two small leaking fuel tanks.After about the third 'grenade' went off, we had to send the airframe back to Howie for a rebuild. It came back with the then new Rotax 582, with electric start, doors, carpet, bigger fibreglass wing tanks, a reduced fin, stronger tail wheel and the all new lowered turtle deck. :-}It's new designation was a GR-582.

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We liker this so much, we bought another one!Eventually though, $4!t happens and our new plane had it's front end written off. :-%When it came back from Howie, it was now an all new(ly referbished) GR-912 with an 80hp four stroke Rotax, long range alloy tanks, a stronger (still) tailwheel and a redesigned undercarriage?!

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I was never happy with the new U/C, but in the last two years it's all I've instructed in, so I've gotten used to it. While our club stayed with these two LightWings, Howie moved on and had a crack at the low G-A end of the market,and produced the GA-55.

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This actually happened before the Rotax 912's were affordable, so Howie, wanting to use a four stroke and keep the G-A types happy, used the Aeropower VW.The GA-55 also featured a totally new wing with less span, a faster wing section, a single strut and flaps!Unfortunately the combination of less wing and not a great deal of thrust changed the LightWing from something that would be airbourne almost by the time you reached full power (if you knew how to treat your two stroke propperly) to a plane that actually needed to build up speed along a runway.I don't think the GA series was ever certified as a factory built (most being kits) and it just sort of died off.I'm sure some GA-55's ended up with 912's, and would be interested to know how they perform?Finally, in the 'GR' line, howie would succomb to pressure and produce the GR-912'T' for trike geared version.

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As for the initial reason for this thread.. :-" I think that a GA-912 with slightly longer wings and better designed flaps would give us an aeroplane that, although probably not that much faster than a GR-912, would be a lot more fuel efficient, while still having all those good Lightwing attributes of good handling, cabin space, visability, ruggedness and general utility.

Arthur.

Just a quick one, while doing a hundred hourly last weekend, I noticed a crack had formed on the brake band attaching tang where it is welded to the stub tube. (forgot to take a photo!) Asked a nearby LightWing operator who then said he had had the same problem.Problem has been welded up but would like to hear of others with the same or similar problems.This reflects from an incident we had about ten years ago when an axle snapped off an LW-1. Severley damaged the aircraft, and we then found that it had happened before to others, but it was not 'common knowledge'! Just looking at the AUF airworthiness site and I don't see any direct 'online' way of submitting a notification other than the 'Defect and Incident Report form' or by emailing the Tech. manager via the 'contact us' link.