IBob

When I came to NZ in the '70s they were using DC3s and Beavers. I was fortunate to go with a friend a couple of times in a Beaver, had another session booked but he rung me and told me not to come out. Weather no good, I asked, nope, he said, I just wrote her off. The strip that day was along a ridge top, he had missed his line on takeoff and gone off the side with insufficient speed. You could see where he started to dump the load, but the reality is the super doesn't come out that fast: imagine sand pouring out of a hole in the bottom of a bucket, it takes time. You could see where the L undercarriage hit and tore off. Then the gouges made by the prop, with the RH undercarriage a little further on. The rest was in a fence at the bottom of the gully. The Beaver fuel tank is in the belly, so lucky it didn't burn. Back up on the ridge, you could easily see how it might happen: the land appeared to fall away just about equally on all sides, with no clear indicator of the line. Apparently they would normally follow the wheel marks of the arrival landing, but that morning there had been no dew and the ground was dry. I never did manage to go topdressing in a DC3, but I once begged a ride in the copilot seat from Napier to Taupo, and it remains one of the most enjoyable and memorable flights of my life.

Just nipped out in the garden and took a pic of our most-used local strip, 2.3km away. The super bin is silhouetted at the top right against the trees on the hilltop. The strip comes down very steeply to the left of there, then less steeply towards it's lower end: only the steep upper part, coming towards the camera, is clear in this pic. This strip sees a huge amount of use each summer. Mostly what they are putting on is lime, to address a deficiency. A couple of summers ago they must have been working close in, and I timed them at 2minute turnarounds, wheels off to wheels off. They work very long days when weather permits. And it is dangerous: more so than forestry, which otherwise tops the list here.

The foiling sailboat performances are certainly outrageous. Having said that, the dynamics, or mechanics, or physics, or whatever we should call it......of the foiling sailboat speeds are a completely different thing than what is going on with this downwind land-yacht. None of the foiling sailboats, regardless of how refined, will go directly downwind at or faster than the wind speed.

Seems I stuffed up the format of my first post here: "In the case of something like an engine, I think I would be keeping it warm, but also shrouding it somehow to avoid constant air circulation." was supposed to be at the end.

I should add that I noticed parts from my build sometimes 'sweating' on the shelves in my workshop. This was particularly the case with the aluminium prop extension and the wheels, both of which are solid aluminium turnings or castings. The process here was that those parts cooled overnight, but due to their large thermal mass, were slow to warm up as the day warmed up. So as the day warmed, those parts remained colder than the ambient air, and condensation would occur, just like a cold glass of beer: the sweating occurred not overnight, but in the mornings as the ambient air temp began to climb. I was able to fix that by moving those heavier parts to higher shelves, so keeping them warmer. I also improved the seal around the workshop door to reduce the ingress of air.

F10, I have done a lot of refrigeration control work in freezing works. Vegans should look the other way at this point. A particular area of difficulty was the marching beam chillers, where the carcases come off the killing chain warm and wet and are fed along a progressively chilled room to age then reduce biological action. The steady stream of carcases is constantly bringing moisture into the room, and the walls and ceiling at the intake end would stream with condensation for a couple of hours after each shift start. This is a meat hygiene nono, so we had people in there with squeegies etc trying to control it. At one particularly bad plant we tried all sorts of things: extra fans blowing air various ways, a low temp refrig coil at the front end to strip moisture. Improvement was minimal. Then one day I was talking with a visiting eng and he said 'You will only get condensation where the surface is colder than the ambient air". I thought about that, then programmed an especially long hot defrost of the refrig gear at the front of the room, timed to occur before start of shift. In the case of something like an engine, I think I would be keeping it warm, but also shrouding it somehow to avoid constant air circulation. And the condensation vanished. By hot defrosting the intake area prior to startup, we were warming the walls and ceiling, so no condensation took place when the moisture began to arrive. And thereafter the walls and ceiling would go to ambient air temperature, so still no condensation. So, the best way to avoid condensation is to keep the air dry. But if you can't do that, another option is to keep equipment warm.

Yep, that's a curly one to get the head around......)

Oops, wrong forum, sorry.

RFguy, what possible benefit would it be to China or Australia to go to war? Clearly China is the next boogyman in the sad and endless list of US boogymen used to maintain the necessary national paranoia, so justifying their defence spending and foreign policies....but that don't mean the rest of us have to buy into it............

Fair comment, Skippy, and if you are manually logging readings, that would seem to take care of that part of the argument. But I wonder how many do that (I can't say that I am actively logging values). And then we have (and will always have) pilots with very varying degrees of knowledge regarding the operation of engines. A well set up alarm system and a check of values at service intervals could be a real benefit for those less focused on the mechanics than you are. To be clear, I was referring only to engine monitoring and there are cost effective compact units to do that for the 912.

I have the basic kit-supplied steam gauges, which I am happy enough with. However, were I building again, I would definitely consider one of the dedicated glass setups for the 912 engine instrumentation. As I see it, the advantages are: 1. Ability to set alarm points, so the unit alerts you to over/under temps or pressures. 2. Ability to log and download temp and pressure values. So, for instance, at set intervals (every service?) I could download those values and compare them with previous readings to give an ongoing indication of engine health.

Nev the frames were not home made, they were from Norton, along with the Roadeholder forks. Perhaps you meant home made in the sense of combining the two. And the fact is that, while the HRD Vincent were a special bike for their time, with many excellent and some unusual innovations, they were quite complicated, required a fair degree of maintenance that not just anyone could do, and were eventually pretty much left in the dust by the likes of BSA and Norton.

(PS before setting up throttle cables, set up carb throttle stops, also idle screw, as per the Rotax manual. It's quick and simple, just so many turns, but I found mine were set up very rough from the factory.)

Marty, that's good info. And I would think the washers are just a tight fit over the lower part? My fasteners have that undercut too. However on the bottom fastener for the lower cowl my test pilot filled the undercut with a piece of tube shrunk on, as the small amount of slop there was allowing too much movement at the pointy end for his liking. Some of my fasteners do have to come all the way out, but I'll look at getting some washers. And I agree with Nomadpete, certainly initially as everything beds in: you will be looking for oil and coolant levels and leaks, exhaust leaks, exhaust spring breakages and any chafing of pipework or wiring due to vibration or contact with the cowls. Plus you will be visually checking throttle synchronisation at max and min, with some initial adjustments of that until it settles.

I came across most of a Brough Superior SS80 in the little front yard of a row of houses in Southampton. Kept going back but there was never anyone home, then one day it was gone. This was the sidevalve version of the SS100 that did for Lawrence of Arabia....(

Imagine what that would be worth now, Spacesailor! (Now, there's an idea for a non-aviation topic: vehicles we had that would now be worth gold.) And yes, I heard of the NorVin: the Featherbed frame and Roadholder forks from Norton were considered the best production units at the time. The Vincent had a sort of undulating motion with it's suspension, though note they had what amounted to the monoshock under the seat for the swingarm decades before it gained popularity elsewhere. Pity about the cast aluminium girder front, the earlier tubular steel ones looked far sweeter..........

PS if you go with the Dzus, get a spare: as someone already mentioned here, they're easy to drop and lose in grass. I've done this a couple of times, been fortunate to find them, nowadays I'm very focused when taking them out and they go straight onto the cockpit floor just forward of the seat/s where they can't wander..)

FWIW the ones I got that go through just 2 layers of f/glass were: Model Cat # 121J-540-Z3C AJ5-40 You probably need something just a bit shorter. There are a few guides online as to how to measure up for them. I found it quite a pleasant job adjusting them by packing or flattening the S spring a bit, though it's best done before paint. I guess the advantage of the screw and nut plate is that you don't have to adjust for thickness....

Marty, they come in various lengths, you'll have to work out which you want. Ideally, you'd look at an aircraft that has them, and use that as a basis for your length measurement. I also spent some time tweaking the S springs they get hold of, in some cases bending or packing those out a bit, to arrive at the sort of action I wanted. But my cowls are fibreglass with almost certainly variations in thickness.

Marty, I have an idea that the cowl inside/outside question is (another) one of those regional things (and eventually it will be possible to tell where a NZ Savannah was born by these local variations). What a great set of instructions. The CS screw setup looks good, and I'm pretty sure that is how c185 cowls are fastened. About all I would add is that I had my cowls off quite regularly in the early days, checking for chafing and leaks etc. And I still take the top one off every few weeks. So I would want to be able to do that quickly and easily, and the Dzus fasteners do that: it would be about a minute to remove, and 2 minutes to put back on.

You did well, Turbo. I had a Series C Comet, the unmodified unit was really a bit of a dog with a top speed somewhere in the mid 80s as I recall. About what you'd expect, I guess, as it was essentially a Rapide or a Shadow without the rear cylinder. I was living in London, and the clutch would progressively heat up in the stop/go traffic: the hotter it got the more it dragged and when it dragged you couldn't get it into neutral which caused it to heat and drag more, which eventually left just two options: stop and wait for quite some time, or ride down footpaths and median strips. I did a fair bit of the latter before graduating to a Goldie......

That's going back some: didn't he and someone else circumnavigate the globe on an HRD.....HRD being what went before HRD-Vincent, then Vincent???

That's looking great! My experience of cowls is entirely limited to what came in my kit, but I'll pitch that in: The cowls (in the Savannah) generally go inside the al fuselage skins (though some do fit them outside). Apparently this used to be a pretty tight fit, but it does not seem to be an issue with the later models. The hugely experienced pilot who test flew my aircraft grabbed it by the holes at the front and tried to move it up and down: I think he was checking against the possibility of the cowls coming off in flight. I now give them a wiggle as part of my preflight, and I like the idea that they are tucked inside the skin, though no doubt there are perfectly safe ways to fasten them on the outside. The upper cowl overlaps the lower, which is stepped or rebated in. The fasteners are Dzus. 3 on each side for the lower cowl, of which the top one is also shared by the upper cowl. Then a further 3 along the join between the cowls at the side, plus a further 1 (per side) close to the spinner. The ones supplied were aluminium, but they bind so I bought steel replacements. There is also a hinged hatch over the oil tank. Assuming you intend burping and checking the oil level of the 912 during preflight, some sort of hatch will save a lot of messing around.

Old K, I wonder if part of the problem might be different mandrel diameters? A quick online search gives a diameter of 1.8mm for various rivets. But a table from boltsandnuts.com shows a 1/8" rivet with a mandrel of 0.076 which translates to 1.93mm. As an aside, I recently bought a very nicely built mastic gun to replace the pressed metal one that I could no longer panel beat into workable shape. When I got the new one home, I discovered it was not quite long enough to load the standard cartridge: so now I must trim about 3mm off the rear skirt of every cartridge with a craft knife........... How do they screw we? Let me count the ways........ (with apologies to Elizabeth Barrett Browning)