pylon500

If this wing flies, you will be surprised how even a small amount of non-moving tip trailing edge will dampen aileron response. That is if that end bit of trailing edge is not going to move. My second aircraft had a wingtip similar to the Sapphire, with (admittedly) a small aileron. Roll response was not startling. Later, the trailing edge was cut off and joined to the aileron, giving much better roll control. I was initially going to go with just a left wing, but was convinced to add a right one as well...

Some companies spend years researching wingtip design; Some don't think it matters...

Will have to give kudo's to Jab for that gear leg! Landed in a plowed paddock and splintered, but still supporting the aircraft!

The 'plastic' blades referred to are the original 'Ultra-Prop' propellers. The plastic blades were a bit of a compromise between production and performance. Enter 'Aerofibre', a composite blade maker in Queensland, who produced the 'Brolga' blades to suit the Ultra-Prop hub system. Upon his retirement, the Brolga blades were produced by Bolly. Interesting looking blade, and if I read right, they will be moulded plastic like the original Ultra blades... Hopefully the MARAP process should sort this out.

Yeah, there is that problem. I suspected as much. The original plastic blades, although they look primitive, actually work fairly well and can easily be cut to length. You avatar talks of a WB582, I would have thought you should be using a four blade prop for that power and diameter? No, I don't have the time to make/repair props, sorry. A friend had the three blade Bolly on his Fisher 503 Drifter, very nice, and quiet. Had a minor hub issue, but Bolly sorted it, a good prop.

It will be interesting to see what the blades are like. Are you actually getting 'Brolga' blades to suit your 'Ultra-Prop' hub, or the plastic 'Ultra-Prop' blades? As I mentioned, when the Broga manufacturer retired and sold the business to Bolly, they said they updated the blades, and with it the price. Not saying they are a bad blade, in fact they ARE better, but at $1,200 for three blades, I decided to make my own. I don't even have an Ultra-Prop hub anymore, just the blocks.

New tanks, new canopy, bit of a buff, no problems...

Saw the prototype of this (probably that one) at Oshkosh '13. Slick as an RV, simple as a Sonex, designed around a Corvair engine, but would take a Jab3300. Folding wings. Was very tempted... It is currently a single seater, but I think a two seat could be in the works, but would compete with old RV4's.

So I went back and had another look at the pictures, and the video footage (which didn't run the first time?). In the close ups on the video footage, I'm fairly sure now that the line across the animal track is definitely the impact mark of the entire leading edge. In some views, you can almost make out the impact marks of the wheels and the nose impact point is quite obvious. The fact the wreckage appears to the right of perpendicular to the leading edge impact line would imply some rotation at the time of impact. No tire marks are evident leading to the wreckage. The distance travelled by the wreckage does equate to a low horizontal velocity, however, the amount of destruction is indicative of a reasonably high speed, more likely in the vertical axis. Beyond that, the picture, and it's quality, are insufficient to postulate further, although the brownish triangle shape spreading from the primary impact point is possibly the spray pattern of a rupturing fuel tank (I think the Fishers have fibreglass tanks like Drifters?), which has killed the grass. None of these observations can definitively state the cause of the accident, only surmise the events post impact.

Something must have gone seriously wrong to leave that impact mark.

? Meanwhile, back at the weight and balance test topic.... Logged into the members portal to do the test, and the first thing that happened was the password I got, was in confusing font, where I had to decide if I was looking at a 1, a small L, a capital I, and then a zero, or an Oh?! Managed to log in the third time. Then spent an entire afternoon trolling through all the mixed info from various official sources; 1975 D.O.T. (Australia) weight control regs, 2011 CASA maintenance regs, 1945 FAA AC 43/10 weight section, 2009 Some word doc discussing W+B, CASA exemption 49/15, And assorted video's. And then delved into the test questions and finally the exam. So, anyone that knows me, knows I've got a pretty good handle on most aspects of design, thus weight and balance, I've been weighing and assisting weighing for a few years now. I will be the first to admit that over the years I've got a bit lazy, and now days I use an excel spreadsheet to do all my W+B work. It's a good app, and I understand how moving things around effects things, and know how to adjust things in the app. Naturally I figured if I've got to check some figures, I'd just use the spreadsheet. Two things popped up; ⁕I overlooked that the actual figure questions were purely mathematical, yes, you need to draw columns and crunch numbers, ⁕The diagramatic aircraft as pictured is basically improbable in the real world. (Don't try to work out the CofG as a percentage as real designers would) The latter being the problem that slowed me down as I tried to reverse engineer the plane to get logical results. End result, failed! No feedback, so idea where I went wrong. Gotta re-engage my old brain and try to learn all the 'different' ways of doing what I've been doing for the last thirty odd years....

Actually, I, pylon500 and two mates are embarking on a new project(s), and we're gonna need all the cleco's we can get our hands on. If anyone has spare/leftover/finished with cleco's, PM me, and we'll look at some sort of deal.

Prop doesn't look like it was developing much power at impact.

He was lucky the parachute didn't tangle with the wreckage. While most ultralights have ballistic deploy systems, that will get the chute clear of the aircraft, hang glider just a have a hand deploy, and they have been known to tangle and not deploy fully.

Unfortunately there are those that will try to 'DRIVE' Foxbats (and Vixens) onto the ground, much too fast, and there are a few broken nosewheels around the place. Even flapless, a Foxbat should not touch the ground above 45kts, and the nosewheel probably shouldn't touch till below 30kts. This is such an easy aeroplane to land...

Thruster?! Nah, it's a Javelin. Another project I'm supposed to finish for a mate (he's in no hurry, got two other planes...)

I've just realised that talking about making props is a bit of a thread drift, so I'll leave it there for now, but will post a link to photos of 'One I prepared earlier'; https://get.google.com/albumarchive/113292981019876413104/album/AF1QipO4Yp7-E7wI6rRX5D_BcFVgmQVh_enL5dZJ3e1O

With the timing and everything, it really was one of those $hit happens scenarios. Although he did seem really positive about making sure it wasn't his fault...?

Well according to most Skyfox/Gazelle owner/pilots, the RAAus office for one..... I know no one else likes/wants them..

Just guessing at the power output (or lack of it) from the Skylark, and low speed airflow, I would be guessing at something in the 34x18 to 36x22 size range. If you don't actually plan to fly the engine/prop, it doesn't have to be perfect. Calculating, marking and carving a prop isn't as hard as many think, the real 'art' is how to lay out the twist and the planform. Really basic propellors like the Scout prop, the Allsize props on the Skyfoxes or many of the WW1 vintage props, use the same concept and simplicity. (I can hear the Allsize lovers getting angry..) Start with a block of wood, laminated if you want, or just a medium weight hardwood (I wouldn't use common Pine, but a nice straight grained piece of Cypress Pine would be OK), I've used darker coloured Maple or Meranti in single block for short use props. The pitch calculations are not as hard as you might think.. Say an 18" pitch, on a 34" diameter prop. A 34" diameter is (Ø x π) which is 34 x 3.14= 106.75" in circumference. An 18" pitch means we want a triangle 106.75" along the base, and 18" high at one end. Using simple trigonometry (or a calculator) you find the angle at the low end of the triangle, 9.57° Lets assume a piece of wood, 34" long, 2½" thick and 4" wide. Draw a rectangle that represents the end of your piece of wood, 2½" by 4". Using a protractor, draw the line that represents the pitch angle from one bottom corner. Take your 34" long prop blank, figure out which way the motor turns (!), and determine the trailing edge at each end of the block. Mark the height as shown by the arrow, on the LEADING edge of the block. (This layout will give you a SQUARE prop!, if you want it tapered, there's a bit more work...) Repeat all the above calculations and markings for each inch inwards along the blank, remember, one inch in on one blade, is TWO inch less for each diameter calculation. You should end up with; All these lines are the UNDERSIDE of the blade section at each point. When the angle goes out the top corner, stop the marking. If that point is more than say 6" from the centre, you may need a thicker piece of wood. From here on, check various youtubes on how to carve (I've got to go to work..)

If you are planning to run direct drive, the old Scout prop would be way too big. I was playing with a couple of Kirby (Tecumseh) 144cc motors back in the beginning, running direct drive props. My last set were 32x16, and could have been maybe a little bigger? Yes, it's a pusher, I was using two of them on a home made trike.

Good point! When do we get w_i_d_e s_c_r_e_e_n avatars?

I use this gif over on Homebuilt airplanes.com, but it would also lose out if stuck in a round hole. (I'm actually amazed I still had this in my computer somewhere!

All the efficiency they gain from the higher aspect ratio wing (which is all it is), will be lost in the biplane interference caused at the strut junction, to say nothing of the section buildup created by the straight strut. NASA, well, I think mainly their students, are coming up with a lot of ideas lately, that don't really make a lot of sense, or miss obvious (counter) explanations that have been known for years. There was a lot of work (and money) spent on trying to prove some nineteenth century bird watchers theories about winglets and like, which I found on youtube; They were trying to prove that a flying wing can be efficient, but really, all it proved was that higher aspect ratio wings are more efficient aerodynamically. Don't get me wrong, I like flying wings, but the compromises involved in getting them as efficient as a 'normal layout', mean dealing with some pretty serious stability problems. It might be OK today what with autonomous artificial stability and stuff, but get it wrong in an airliner, and it'll suddenly turn into a cloud of composite bits and bodies hurtling through the sky....