# A challenge to you all

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#### deskpilot

##### Well-Known Member
My apologies. I'm amazed, it looks like 95:10 has changed and I didn't notice it. 95:55 (for two seaters) still has that restriction. Here's a link, you can also find the 95:55 on the CASA site - Civil Aviation Order 95.10 - Privately built single place ultralight aeroplanes - Exemption from compliance with certain provisions of the Civil Aviation Regulations 1988 (12/12/2004)
Nothing has changed as far as I know. Rules have always been, anything goes provided it weighs no more than 300kg with a wing loading no more than 30kg/sq m. Can built of non aviation certified materials as well.

It's sooo nice to be right sometimes :roll:

##### Well-Known Member

It’s clear that some will want to build from wood. I can’t see a problem with the general configuration also being suited to that for the fuselage but it might be a problem to have wood wings because the pilot sits in the space between the wing spars and in this case the front spar is on the leading edge. With a timber wing the spar would be at the thickest part of the wing, around 30% chord and that would mean that the carry-through compression member would be right on the pilot’s chest. So unless we have a completely different aircraft configuration (high wing but then we need a kingpost, or low wing with struts in compression) the timber builders might have to accept some hybrid compromise, with a timber fuselage and metal/fabric wings.

The initial fervour seems to have worn off and the thread slowed down so maybe we need some direction and goals?

As a first goal I’d like to suggest a timeline. I haven’t got a lot of spare time and this is already cutting into my project building time but I think it’s a valuable and worthwhile contribution to make to sports aviation, which after all, has given me a lifetime of excitement and adventure – and crammed it into just half a lifetime so far!

Goal - I see no reason why we can’t have some basic working drawings within three months if we have enough interested contributors.

Initially we need to decide what proprietary components we will use for the prototype. Stan (the thread OP) said he’d build the prototype if we designed it but he hasn’t surfaced since the thread got moved and received comment. I PMd him but haven’t heard back so maybe he gave up. Does anyone know him? Anyway as the design develops into something good I’m sure we’ll get a volunteer to put one together.

First we need some volunteers to do the basic sourcing research, please make suggestions and also provide links and prices. Many suppliers also have CAD files of their products which would be invaluable in saving time creating the CAD model.

Please choose something to help with in your area of interest/expertise from the list below –

ENGINE – your call but I would suggest something designed for aircraft with gearbox/psru because most folks can’t build/convert their own. Don’t forget there’s no substitute for horsepower when it comes to getting out of trouble and some countries will allow this to be a two seater which would be easy enough with a small stretch of the fuelage. On the other hand we want cheap power so maybe just enough horespower for a single seater to begin with?

PROPELLOR (AIRSCREW) – a source of good cheap timber ones probably, with l/e protective insert preferably.

WHEELS/BRAKES –

TAILWHEEL –

MONOSHOCK, AIRSPRING, or build our own? –

TUBING FOR FUSELAGE – I’d suggest industrial grade radiused square tube for easy gusset/pop-rivetting. In Oz we can get 5/8”, ¾”, 1” x 3/64” and 1/16” wall thickness and also larger sizes and rectangles etc are they available elsewhere?

GUSSETS FOR FUSELAGE TRUSS – can someone find a machine shop with a large flywheel press, we need to punch discs of about 5” diameter 1/16” aly sheet to make the gussets.

SEAT – the lightest possible for this configuration actually contributes to the structure and is just a couple of fuselage crossmembers with fabric laced around them like a campchair. We need to find the strong webbing style fabric and someone who can sew it (sailmaker/industrial machine). BTW another good aspect of this design is that the deep fuselage allows for a seat placed well off the floor so the seating position is comfortable and there is plenty of room for controls to pass under the seat, with good access to maintain/check those controls by simply unlacing the seat fabric.

FLYING AND LANDING WIRES – due to the lower bracing angle of wires on this mid-wing, than on a high-wing the loads on the wires will be significantly higher than on the high-wing designs. Nonetheless wire sizing gleaned from existing designs will be a good starting point for our design. So can those with wirebraced planes please measure the wire diameter or circumference (say which it is) and determine the lay type (1x19, 7x19, 7x7) etc and provide a list detailing which wire it is i.e. front inner flying wire, rear outer flying wire, front inner landing wire, tailplane top front bracing wire etc and provide the type and MTOW of the plane you are measuring and also the bracing angle of the wire (or the length along the wing from the spar attach points and the vertical distance from the spar attach point to the wire attach point). We will need wire of 2-3 times the cross sectional area (CSA) of, say, a Quicksilver but I’m sure the engineers will work that out more exactly for us. Preferably several people might be able to provide these lists so we have a basis for comparison. Also the information may be available from suppliers of spare parts for these planes??

RUDDER PEDALS -

ANYONE HAVE A FRIEND WHO HAS A LASER OR WATERJET CUTTING MACHINE? For bellcranks, control horns etc

PHOTOS OR SKETCHES OF CLEVER THINGS on existing planes – anything you think we should incorporate

WING STRUCTURE – Sizing of spar tubes on similar tubular spar existing aircraft, also their inner sleeves/doublers etc, again we’ll need to increase the sleeving due to the increased compression factors on the inboard part of our wing caused by the lower bracing angle of the mid-wing design.

FABRIC – your call but heatshrink (Stits type) is easier for the homebuilder to sew up themselves than sailcloth type, avoids battens and can be ribstitched for better shape retention at higher airspeeds. Also doesn’t get UV degraded if silver dope is applied properly, so it lasts for many years with little or no maintenance.

CONTROLS – suggestions? No descriptions without sketches please….

Anything else you can think of – happy hunting.

##### Well-Known Member
Nothing has changed as far as I know. Rules have always been, anything goes provided it weighs no more than 300kg with a wing loading no more than 30kg/sq m. Can built of non aviation certified materials as well.

It's sooo nice to be right sometimes :roll:
Yes, when I thought about it I was confusing an interim ANO which was maybe the original (pre-amendment) 95:25 IIRC, and before 95:55. And of course they're CAOs now not ANOs.

And 95:10 has changed but you're probably fortunate enough to be too young to remember the earlier versions... Pre-amendment it was in lbs not kg and it was max empty weight 254lb, MTOW 400lbs (that's way less than 300kg), max wing loading 4lb/sqft (that's less than 2/3 the current permissible wing loading), and we had to fly below 300ft and not cross any road (round the paddock only) - the current issue of CAO 95:10 is issue 5...

So the present 95:10 is very liberal on design restrictions compared to what we were working with initially.

And BBerson is quite correct in his post #44, that the Macro doesn't fit USA's Part 103 because although it only weighed 198lb/90kg the wing loading was too high, and in fact that also made it an 'illegal aeroplane' here in Oz (there was no other possible description of it, not even 'light plane' as BB suggested). At the time most of us were sure that we would eventually get a less restrictive weight allowance and having lost so many friends through structural failure we just built the planes as light as we could and hang the rules - hence the comment in Janes about the Macro 'being built for the new ultralight cross country category' (which hadn't yet materialised). We also lied a lot about wing area and weights and failed to turn up for Dept weigh-ins and measures (broke down on the way usually )

Ironically the Macro would now be a legal ultralight in Oz, with the 10kg/sqm current allowance it just fits in. And probably Aircar's gorgeous Stilleto (Stiletto?) would also - of the very light aircraft genre the Stiletto takes my prize of all time best.

#### StarJar

##### Well-Known Member
Sorry I went on such a rant about wood and pine, I somehow got to thinking it was a wood plane:emb:.

But in anycase I'd like to research the.... brakes and wheels; the shocks; and the rudder pedals.

By the way, for wing tips, Orion once mentioned tips that sweep back 55 degrees or more, to get a simple vortex effect. It seems pretty simple, and probably would not stall even if the edge was tube radius. (The last part about the tube is my guess,..) In other words angled off like a Wittman Tailwind, but at the correct angle to allow a vortex (55 degrees, or 35 degrees depending on how you place the protractor.)

I thought that might be a simple solution.

##### Well-Known Member
Sorry I went on such a rant about wood and pine, I somehow got to thinking it was a wood plane:emb:.

But in anycase I'd like to research the.... brakes and wheels; the shocks; and the rudder pedals.

By the way, for wing tips, Orion once mentioned tips that sweep back 55 degrees or more, to get a simple vortex effect. It seems pretty simple, and probably would not stall even if the edge was tube radius. (The last part about the tube is my guess,..) In other words angled off like a Wittman Tailwind, but at the correct angle to allow a vortex (55 degrees, or 35 degrees depending on how you place the protractor.)

I thought that might be a simple solution.
All good.

No problem about the timber thing, it's good. A truss fuse lends itself to timber construction as well anyway, often with very thin ply as the skin rather than fabric. The timber can be smaller section that way and the overall result is similar in weight and strength. Suits some folks to work with timber. I can't help with timber sizes/types/specs but we should just keep the overall thing shaped in a way that doesn't exclude that kind of construction material/method, so that this can be a resource for more builders.

Thanks for volunteering, excellent, that's a great start!

No-one should be discouraged from also working on any particular area as well, since we may all find different things. That is the great benefit of an open source project, the potential to have a large critical mass...

And - excellent contribution to have remembered about the wingtip shape, Orion certainly knows his stuff! I'll start to make a folder to assemble the ideas for inclusion so they don't get lost in the thread, and post them every so often, unless someone would like to volunteer for the admin aspects?

About the wingtip angle, and since it may be useful for describing other parts of the project, there is a drafting convention for showing angles in relation to something else. If a length of material is to be cut off square it would be cut at 0 degrees, if almost square it would be cut at 10 degrees ish and if it was to be cut into a long taper it might be cut at 80 degrees. So the angle is measured from square to the length of the material. That's for shop drawings and cutting material. As far as the wingtip is concerned we'd probably think of it as the sweep of a wing so the angle would be measured from the spanwise direction (quite the opposite) so I guess the wingtip angle is 55 degrees - all good fun isn't it...

#### Vector

##### Well-Known Member
Here is my suggestion on Engine - Rotax 582 is a good engine; cheap and affordable. Though TBO is only 500 hours, that is enough for most people as the average private pilot only flies about 100hours a year.

#### stan40353

##### Well-Known Member
looks like i have some reading to catch on, had some deaths in the family, kept me offline for a bit. looks like people have been working at this

#### StarJar

##### Well-Known Member
looks like i have some reading to catch on, had some deaths in the family, kept me offline for a bit. looks like people have been working at this
Wow. Sorry to hear about the deaths. Condolences on that, man.

Welcome back, we'll need all the help we can get.

#### PTAirco

##### Well-Known Member
Here is my suggestion on Engine - Rotax 582 is a good engine; cheap and affordable. Though TBO is only 500 hours, that is enough for most people as the average private pilot only flies about 100hours a year.
If the goal, as stated at the beginning of the thread, is a Part 103 ultralight, the Rotax 583 is way too heavy. My choice would be one of the MZ engines - the 201 only weighs 70 lbs or so and puts out 45 hp.

I have always thought that a biplane is the ideal configuration for this class of aircraft. All the usual objections don't really apply here. Biplanes are an ideal solution if you require a large wing area with minimum weight. Top speed is of no concern to us as we're limited to 63mph anyway. It's also compact and more maneuverable and thus more fun to fly. With folding wings (think Gypsy Moth) it could easily fit into a box trailer. It looks neat and has mass appeal, at least to those of us already into airplanes. maybe not so much to those people who stray into ultralights from other interests such as off-roading or jet skis, but who doesn't like biplanes?

The weight limitations could be met fairly easily and you end up with a conventional aircraft structure, not a flying lawn chair. Yes, it will be delicate on the ground, and the parts count is high and construction just as demanding as for any other "regular" homebuilt, but you do end up with a "real" aircraft. If it's designed for the homebuilder, the fiddly construction and large number of parts simply mean longer build time, but it shouldn't be any more expensive. I'm thinking welded steel tube fuselage and tail (tiny, tiny tubes....0.028 and 0.035 thicknesses - practice your welding), wood wings with foam/wood or conventional built up ribs or metal wings with simple folded sheet metal C-section spars (I really dislike typical UL ladder type wings with tube spars...) and flanged ribs.

I have gone through a few preliminary napkin calculations and the structure weight is very low for that type of construction - IF you do your homework. Wings would have a very mild stagger and fold straight back, five minute operation.

The look of the aircraft could easily be modified by altering tail shapes, wing tips or the (carbon?) turtledeck and cowlings to fit your own ideas; from WW1 style biplanes to a classic 30s look or a more modern Pitts/Starduster look.

It does require a lot of arithmetic, you don't have ounces to waste in this category and every part needs to be optimized.

#### George Sychrovsky

##### Banned
I forgot the deathtrap pic

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##### Well-Known Member
looks like i have some reading to catch on, had some deaths in the family, kept me offline for a bit. looks like people have been working at this

#### StarJar

##### Well-Known Member
If the goal, as stated at the beginning of the thread, is a Part 103 ultralight, the Rotax 583 is way too heavy. My choice would be one of the MZ engines - the 201 only weighs 70 lbs or so and puts out 45 hp.

I have always thought that a biplane is the ideal configuration for this class of aircraft. All the usual objections don't really apply here. Biplanes are an ideal solution if you require a large wing area with minimum weight. Top speed is of no concern to us as we're limited to 63mph anyway. It's also compact and more maneuverable and thus more fun to fly. With folding wings (think Gypsy Moth) it could easily fit into a box trailer. It looks neat and has mass appeal, at least to those of us already into airplanes. maybe not so much to those people who stray into ultralights from other interests such as off-roading or jet skis, but who doesn't like biplanes?

The weight limitations could be met fairly easily and you end up with a conventional aircraft structure, not a flying lawn chair. Yes, it will be delicate on the ground, and the parts count is high and construction just as demanding as for any other "regular" homebuilt, but you do end up with a "real" aircraft. If it's designed for the homebuilder, the fiddly construction and large number of parts simply mean longer build time, but it shouldn't be any more expensive. I'm thinking welded steel tube fuselage and tail (tiny, tiny tubes....0.028 and 0.035 thicknesses - practice your welding), wood wings with foam/wood or conventional built up ribs or metal wings with simple folded sheet metal C-section spars (I really dislike typical UL ladder type wings with tube spars...) and flanged ribs.

I have gone through a few preliminary napkin calculations and the structure weight is very low for that type of construction - IF you do your homework. Wings would have a very mild stagger and fold straight back, five minute operation.

The look of the aircraft could easily be modified by altering tail shapes, wing tips or the (carbon?) turtledeck and cowlings to fit your own ideas; from WW1 style biplanes to a classic 30s look or a more modern Pitts/Starduster look.

It does require a lot of arithmetic, you don't have ounces to waste in this category and every part needs to be optimized.
Wow I like this idea too.

It seems like a main feature of our "build group", is that we can come up with improvements, on the way it's been done before. For example, if we did go with a biplane, maybe we could add in the engine platform idea, the tailwheel idea, and any other good stuff we think of or find.

It's funny I should mention that, haha, but in my duties as 'wheel and brake', and 'rudder pedal' man, I started to see a conflict, in products offered, compared to our mission.

The problem is for a plane like this it makes sense to have some brakes, but not neccessarilly, dual brake control. The cost, weight, and neccessity of it, I'm talking about. So I was looking at single lever sytems. BUT you can't really have a single lever system without it being hydraulic, otherise a cable sytem is never going to give you even, straight braking. Are you with me?

Also there really is no cheap light single lever system. Black Devil is the only hydraulic one I could find and I'ts 450 dollars, (but they do include wheels and tires) and kind of on the big, and heavy side..

So I did a little thinking, and thought, why not just put a single brake on the tailwheel. Of course, you probably want to use a more substantial tail wheel, and it could be a cable or hydraulic brake.Perhaps use a bicycle calliper type, or mini-go cart type of brake.

Since we might use a rudder mounted tailwheel, maybe we can solid mount it, and use a small pnuematic tire, and forego any spring.

I wanted to see if you guys would approve of this approach to keep things simple, light, and inexpensive. If I recieve a tentative approval I'll do more research to show possible choices and prices.

##### Well-Known Member
If the goal, as stated at the beginning of the thread, is a Part 103 ultralight, the Rotax 583 is way too heavy. My choice would be one of the MZ engines - the 201 only weighs 70 lbs or so and puts out 45 hp.

I have always thought that a biplane is the ideal configuration for this class of aircraft. All the usual objections don't really apply here. Biplanes are an ideal solution if you require a large wing area with minimum weight. Top speed is of no concern to us as we're limited to 63mph anyway. It's also compact and more maneuverable and thus more fun to fly. With folding wings (think Gypsy Moth) it could easily fit into a box trailer. It looks neat and has mass appeal, at least to those of us already into airplanes. maybe not so much to those people who stray into ultralights from other interests such as off-roading or jet skis, but who doesn't like biplanes?

The weight limitations could be met fairly easily and you end up with a conventional aircraft structure, not a flying lawn chair. Yes, it will be delicate on the ground, and the parts count is high and construction just as demanding as for any other "regular" homebuilt, but you do end up with a "real" aircraft. If it's designed for the homebuilder, the fiddly construction and large number of parts simply mean longer build time, but it shouldn't be any more expensive. I'm thinking welded steel tube fuselage and tail (tiny, tiny tubes....0.028 and 0.035 thicknesses - practice your welding), wood wings with foam/wood or conventional built up ribs or metal wings with simple folded sheet metal C-section spars (I really dislike typical UL ladder type wings with tube spars...) and flanged ribs.

I have gone through a few preliminary napkin calculations and the structure weight is very low for that type of construction - IF you do your homework. Wings would have a very mild stagger and fold straight back, five minute operation.

The look of the aircraft could easily be modified by altering tail shapes, wing tips or the (carbon?) turtledeck and cowlings to fit your own ideas; from WW1 style biplanes to a classic 30s look or a more modern Pitts/Starduster look.

It does require a lot of arithmetic, you don't have ounces to waste in this category and every part needs to be optimized.
PTA has some very good points here and they're suggesting a different direction completely from what I put up as a suggestion to promote discussion.

I also think the 582 is too heavy and use of it would mean radiators and hoses which is more complication/build time.

I have no intention of pushing any particular barrow, if it is to be a 'plane for the people' then we need to determine what a majority of the people want (we'll never please everyone of course), to that end I think we're going to need regular polls. I've been trying to create one since Bruce put up the first one but haven't been able to make one work. I'll keep trying but any help or point me in the direction of site instructions would be appreciated.

MZ engines look good and light, probably 45hp is about right, the crankcase induction (reed valve?) should be more fuel efficient than the 503 was. Does anyone know the prices?

There's no doubt about the general appeal of biplanes and whatever the configuration the final product can be quite easily personalised by wingtip/control surface etc variations.

Structurally you can't beat the biplane but I do have a couple of reservations worth mentioning at this early stage. Visibility is worse than a high wing and a low wing. The builder has to make four wings instead of two, whether that's good depends on whether the builder is in it for the building or the flying. I'd sort of imagined we'd aim to make something as uncomplicated as possible so as to get flying sooner.

I also like folding wings, that's what I'm building these days but they're very complex on a one-off, probably best suited to production, jig-built aircraft I would think. I can see the top wing folding of a bipe but where would the lower wing go? Or would it not be the plan to get it as narrow as roadable?

And the folded spars are lighter and also my preferred wing structure but another thought I had about the whole project is that maybe it should be designed so that any builder, anywhere, can make it from plans rather than a kit (not to stop kits being available though) with minimal tools and tooling. With just a small bag of dedicated hardware the ladderwing type can be made by someone with a drill, pop-rivetter and a few spanners but as soon as we add folded spars you need access to a machine shop or expensive shipping from a parts supplier. Also the ribs have to be cut out and beaten, anyone can do that but it's time consuming, whereas the ladderwing's ribs can be made from small tubing rivetted together in a simple jig.

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BJC