Peter Anson

This is just a reposting of a thread I put on the Sonex builder's forum. There has been a fair amount of discussion recently about fitting heavier engines, particularly the Corvair, although that would be an unlikely choice in Australia. however, their is a price to pay when you increase the maximum all up weight from that specified by the designer. I can't tell you what the fatigue life of a Sonex is because it depends on so many different factors, but there has been a fair bit of discussion recently about the pros and cons of fitting heavier engines and flying with a greater maximum all up weight so I thought I'd toss in a bit of information about one of the consequences of increasing the weight of your Sonex. The above graph shows stress against number of cycles to failure. It's not necessarily for 6061-T6 but it is a typical for S-N curve for aluminium. You'll notice that the bottom scale is logarithmic, not linear. If you pick any particular stress and then add just 10% to it, say by going from 200 MPa to 220 MPa, it results in roughly a halving of the fatigue life. You could argue that the Sonex is so strong that fatigue will never be a problem, and you could be right. I certainly have confidence in my Sonex but there is a weak point, even in those massive main spars, and it's not hard to increase all the stresses by 10%. For example, by increasing the MAUW from 1150 pounds to 1250 pounds, an increase of 8.7%, you are actually increasing all the loads by about 9.6% (the weight of the wings doesn't count as part of the load). If you'd like to read about this in a bit more detail, go to my blog at How Strong is the Sonex? | Peter Anson – Engineering Peter Sonex 894 357 hours and going strong

I'd like to back up Yenn on this. At Narromine there is no access to parked aircraft for the general public; good for security but not for interest. I went to the last Old Station fly-in and remember spending quite a long time talking to a couple of kids who were keen on becoming pilots. It was good for them and didn't do me any harm either. I always wander around and look at the aircraft myself so this should be available to the general public. If they can do it at Oshkosh, why not here?

Have the same problem but a friend showed me a neat and simple trick - lay the end of the dipstick against a bit of clean rag or paper towel. The oil soaks into the towel and shows up better than on the stick.

Probably not strictly true or passive headsets and earmuffs wouldn't work. High frequencies are pretty easy to damp out. Our problem is that most of the sounds in an aircraft are fairly low frequency,which I have to admit are best damped by dense material, or a mixture of lots of different frequencies. I had some success at damping out sound in my Sonex, just not at cruise speed, which is the only part that really matters.

I did fairly extensive testing trying to reduce noise in my Sonex which also has lots of large flat panels. See SonexAus - Cockpit Noise. I can't say I was very successful and intend trying a couple of "hot dog" mufflers on the exhausts. I couldn't fit the original Jabiru muffler because there simply wasn't room inside the cowl. Peter

I think the Japanese torpedo bomber dive bombing Darwin, and yes, armed with a torpedo, in the movie "Australia" beats this hands down.

I'm pretty happy with my Sonex with Jab 3300 engine. I meets all your performance criteria: cruises at about 125 knots (some are faster than mine); fuel use usually works out at less than 20l/hr; all metal; fun to fly and I built mine for under $35K. The trade-off is that they are pretty cozy. You can still build the original model from scratch. Unfortunately, the B models are only available as a kit and cost as much as an RV.

Paint vs plastic wrapping probably deserves a separate thread but I do have a reservation about wrapping - small holes from stone dings could allow the entry of moisture and promote corrosion under the shiny surface. Even 6061 will corrode very nicely under a plastic coating.

Getting more technical, I have a Princeton capacitive fuel level sensor coupled with an MGL Stratomaster Ultra Horizon. It is very reliable but was a real pain to fit and calibrate. It is fitted from the bottom of the tank but I'm guessing it could be calibrated for fitting from the top. I think they are also sensitive to fuel type. If you use a mogas you will get different readings from using avgas and I have heard that ethanol kills them.

That's a good point. I don't fly model aircraft but I remember being impressed by the power of modern electric model engines when a friend demonstrated one for me. It's interesting hearing the comments of the guys test-flying the 3D printed models in the Youtube videos. They talk about how realistic the aircraft looks while it is flying. I think that's the result of the models being somewhat heavier than the usual molded foam models so that aerobatic maneuvers are slowed down so that they appear more like a full size aircraft. 3D printing is practical right now for some things, even with the cheap little plastic dribblers that people like us can afford. For example, I have made replacement nylon cutter blades for my wife's little electric brush cutter. The air vent pictured in my earlier post features a nylon 12mm x 2mm pitch, double start thread that would only be feasible by other processes if you were making tens of thousands.

I'm still guessing - nothing on the site about how long it takes to print a model. I'm leaning to a longer time than 2 weeks.

It's amazing what he can do playing golf isn't it?

We are still a long way from economically making useful structural parts by 3D printing. My guess is that beautiful Spitfire model would take a couple of weeks to print and is probably fairly fragile. Even the little air inlets that I make take about a day of printer time. And no, I don't print the aluminium.

I think we all know what nut plates and rod ends are but are having trouble thinking of how you are going to use them together.

You'd see a bit more of it if you joined the navy. I'm pretty sure that's Nowra.

OK, Skippydiesel says resist by not applying for an ASIC, which I sort of agree with, but the problem is that we won't overwhelm them with a show of disobedience. A few random pilots may cop very large fines while the rest will save a bit of money and wasted time, so my question is: Has anyone been fined for not having an ASIC at a security controlled airport?

That's quite a trip. Lots of weather dodging. Got to admit my favourite was the heavy duty hangar at Finow. Your aircraft is definitely safe from hail damage in there.

Hmm. I bought my prop from the new crowd who were struggling with problems left to them when they bought the business. Not much help to me though. I still ended up with $1900 worth of rubbish. Incidentally I am reasonably experienced: built my aircraft from scratch, have rebuilt and upgraded my engine and have even reshaped a prop that was not correctly pitched by a US manufacturer. Been happily flying behind my modified prop for 150 hours now. If after all that I can't fit a composite prop it must be an arcane skill indeed.

I think that the props Bolly make for Jabiru are glass fibre while the ones that Bolly sell are carbon fibre so much stiffer. Jabiru obviously thing the more flexible blade is better for their engines. This was the early Bolly "Duralite" composite hub prop which shed blades on the 2200. My own experience using a Duralite on a 3300 was not as instantly dangerous but also unhappy. My 2 blade prop cost $1900 over 6 years ago. Looked schmick, worked well but the bolts needed retorquing every 25 hours (well less than that really) and when I did my 100 hourly I found that the blades were mis-tracking by 6 mm. I sent it back to Bolly who said there was nothing wrong with it. I made a tapered shim to correct the problem but 15 hours later the tracking was out again. What was happening was that the composite hub was creeping, gradually changing shape. Yes, it was always torqued carefully to Bolly's recommended specification. I could actually measure the distortion. It's definitely worth waiting a few years for somebody else to test a manufacturer's new products. For the past 4 years I have been using a wooden prop with no problems.

The jack weighs around 400 grams. It is suitable for tyres 11" to 13" OD. Might not be suitable for much larger tyres even with some type of adapter. If you'd like more details, contact me via my web site. Peter

Hi Bill, the jack was intended to lift by the axle. See http://www.ansoneng.com/sample-page/products-summary/quick-lift-wheel-jack/ for information and links to a couple of videos demonstrating its use. I have sold a couple to people with aircraft other than Sonex, but I'm not familiar with the axle arrangement on Jabirus so it might not be suitable as is.

Hi Bill, I remember speaking to you. We were heading to the coast but stopped at Cobden because Dorian was getting a bit airsick. Thanks everyone. It's obvious from my blog that I think it's a great destination. Length of the runway was no problem for something like the Sonex, although it does drop off a bit at the ends. It could be very difficult in a strong westerly. The runway is 03/21 and very close to a parallel range of hills but there are alternative airfields in the area. Arkaroola is PPR so you can get the latest information when you call them. They are very aircraft friendly.

This was my first visit to the Flinders Ranges and included what for me was a new level in remote flying. It was an 1100+ nautical mile round trip and I somehow contrived to fly the whole thing against headwinds. The scenery was fabulous and I hope to go back some time soon. Here's a link to my blog: http://www.ansoneng.com/sample-page/sonex-trips/arkaroola/ [url=http://www.ansoneng.com/sample-page/sonex-trips/arkaroola/][/url] Peter Anson Sonex 19-7898

St Leonards on the Bellarine Peninsula. Easy to pick if you are flying in that area.

Just when you think you have it all covered, not flying in the lee of mountains, avoiding storm clouds, flying below the structural cruise speed etc. here's my experience flying my Sonex with a friend near Mount Gambier early last year: It was a warm summer day and the sun had been heating the ground up but cloud had moved in from the sea forcing us down to about 2000 ft AGL, so we were bumping along copping both turbulence from the clouds as well as thermals off the ground. Speed was backed off to under 110 knots when we passed over a pine plantation, much darker than the surrounding country, and hit a "wall". There was quite a loud thump and we were thrown up against the seat belts, head-sets dislodged and ipad hit the canopy followed by relative calm and an uneventful landing, although I was pretty careful to avoid other pine plantations. Maximums recorded on the G-meter were +6.9, -0.5 The relevant figures for the Sonex are: Flight load at MAUW: +4.4g, -2.2g Vne 171 knots Va 109 knots Vc 118 knots And that's how easy it was to exceed the allowable flight load by 57%.