IBob

OME Paramushir is an Island off the Kamchatka Peninsula, occupied in WW2 by the Japanese, with multiple airstrips and bases. A Russian translator showed us round the little museum there. On the wall was a picture of a Russian general of Mongolian extraction, who he said should have been shot. The story he told went as follows In addition to extensive military operations, the Japanese had a Russian POW camp on Paramushir. With the end of the war in sight, they loaded the POWs on boats, took them out to sea and dropped them over the side. On Aug14 1945, the Japanese unconditionally surrendered. However, the Russian general, wishing for a decisive win on his CV, requested and was granted leave to 'take' Paramushir by force. Russian troops arrived by ship Aug18, however, they put in to the wrong bay, and 2 of every three drowned while trying to reach the shore. The history books say that sporadic fighting then continued until Aug23, however the translator told us the Japanese met the Russians with white flags and were machine gunned. It is a fishing island, and the locals said they were fishing up bones for years. The main fishing town was wiped out in 1952 by the Severo Kurilsk tsunami. The locals told us the KGB visited the survivors and cautioned them against talking about it. The local theory is that the tsunami was the result of a bomb test. In 1983 commercial flight KAL007 'strayed' into Soviet air space and was shot down. One theory in the West was that the incursion was deliberate, intended to provoke the USSR into lighting up all their defence gear, much of it on Paramushir, so the US could get a look at it. We asked the translator about that and were told the official line: supposedly Russia had shot down 15 enemy aircraft that day, unfortunately one turned out to be civilian. I don't think he believed it: there were a lot of Russians jokes about their own propaganda. In 1986 when I was there, the island was still littered with old munitions, the local children periodically blowing bits off themselves while playing with them. It's a place of severe winter weather, and there are fewer people there now.

I worked alongside NATO troops in Germany, late '60s early '70s. I heard a few stories about things that happened during WW2 there, the reasons and the justifications. Now, when I read back about those same events and incidents, I find the stories are sometimes quite different, and usually nothing like as clear cut as what I was told back then. It can be very hard to arrive at what actually happened and why. The victors get to write the history in the first instance, and the propaganda can last a very long time. I have learnt to be wary of the official line.

Terrific mass Mitchell takeoff footage from the original Catch 22:

Interesting writeup on the reverse engineering and subsequent build of new Oberursal UR.II engines to go in the 'new ' Fokker DVIIIs (of which there are now at least 2): https://thevintageaviator.co.nz/projects/oberursel-engine/oberursel-ur-ii-rotary-engine-build-history

Yesterday I watched one of these take off...and climb like crazy. According to Wikipedia, the climb rate is 1640ft a minute, or 10min 45sec to13,000ft. MAUW 605Kg, engine Oberursel UR.II 9-cyl. air-cooled rotary 110 hp Pretty good for a 100year old microlight!!!

KGWilson, I believe (at least) one of those was an all new airframe build, since the airframe of the original donor aircraft was too far gone. Which meant they had to make moulds for the fuselage. If they now own the moulds, they must be uniquely placed for further rebuilds.

Thanks for that, Downunder. #40 and #30 only required for the Savannah (I think). If I were starting again, I would definitely get them: as stated earlier, it was the only tool I did not have that I wished I had.

Really nice looking tools, Yenn. However, here again we run into the countersink angle problem: the tools offered by Aircraft Spruce cut a 100deg countersink, but the standard countersunk blind rivet has a 120deg head. And this is what I kept running up against when trying to source individual countersink bits...

You are absolutely right, Facthunter, and unless both job and drill are rigidly held, the result will not be a precise neat countersink. So, it's certainly not best practise. However, the tailfin Luca is working on does this in two places: First to hold two nut plates on the back of the main post. Second at the bottom of the skin on one side, where the rivets will be alternated with rivnuts, which then hold in place an inspection panel. These are typical of the (limited) use of countersunk rivets on the Savannah: nowhere are they used solely to hold a skin on. Typically they are used where something else will be mounted over the rivets, which therefore need to be flush. I am not aware of any failures due to this on Savannahs, or 701s.

PS while there are lots of countersink drill bits advertised, almost all of them (like this one) have the wrong countersink angle for the rivets we are using.

1. I'm sure Derekliston's reply above is the correct way to be doing it. However, as he points out, it is necessary to dimple both the skin and the part it is being riveted to, or the skin will not sit down flush 2. However, at the very start of the Savannah manual (General Information, page 2/12) where it outlines various techniques, it says for countersinking 'Just remove the material that is necessary to make the head of the rivet flush with a drill bit'. While this may not be ideal, I expect it is what most builders do. And in the places where rivets are countersunk on the Savannah, it does seem to work okay. 3. If doing it this way: Use a much larger drill (8mm or larger) Ensure that the drill tip is the correct angle (not all drills have the same tip angle, see attached pic) Turn the drill by hand and NOT with an electric drill. It's okay to have the drill bit in a drill, but turn it by hand, not with the power. The reason for this is that if you use the drill to turn it, it is very difficult to control the depth of the cut, and very easy for the drill to grab and pull entirely through, leaving you with a big hole. 4. While this does the job, if I was building again, I would buy a countersink drill bit: this has a tip that fits through the hole and keeps the bit centered. It was the one tool I did not have that I wish I had had.

Another very special aircraft........sigh...........)

Some really good input, and much to think about here for me. Thanks to all. In many ways the Savannah is an easy case, being high winged. And the 6litre receiver behind the seat, with low level switch in the top, is an excellent part of the setup: provided the switch and indicators are working, the pilot is alerted when down to 5litres of fuel in the receiver. (And the one proviso here is that the test button on the panel tests only the indicators, it cannot test the switch. So if intending to use the indicator to fly a tank dry, I first test the low level setup on the ground by valving off all fuel to the receiver, and looking for the indicators to come on during initial runup and taxiiing.)

The vast majority of Savannahs are tricycle undercarriage, and work very well that way. My thought is that while the tailwheel probably has some advantages for specific operators/applications, if it was generally a better configuration there would be more demand. I'm ambivalent about the Y stick: there are many configurations of aircraft controls, and provided they are not uncomfortable, you just get used to them. The Y stick has to be easier to get in and out of, unless you have removable sticks.

Nobody, thanks again. I believe I have seen the underwing vent on a 185: from memory approx 3/8 pipe bent forward like a stubby pitot. Interesting to note it has a check valve: I imagine this would be a simple swing valve. Yes, given the large effects of very small pressure changes, the cross-venting makes every sense.

Nobody, thank you, I wasn't aware of that, and it's given me something to think on. Putting on my fix a problem and make a problem hat (something I seem to have a talent for): with the 172 arrangement you describe you'd need to be very sure that single vent could not be blocked, or you would lose all fuel feed....

Downunder, you read my mind. 2 - AM I FLYING SOLO LH DOWN A BIT? The outer long range tanks came in handy for checking this one: I worked out that my offset weight in the driving seat was equivalent to 15Litres of fuel offset in the R Outer tank. So I tipped 15Litres of fuel into the R Outer tank (L Outer obviously empty) and went for a fly. It made no difference at all: I'm still landing with my R Inner tank 10 to 15Litresd below my L Inner tank.

The Savannah receiver tank is normally vented to a point high on the L Inner wing tank. The principal purpose of this is to ensure the receiver is flooded, avoiding air in the receiver which can result in false 'low fuel' indications from the switch in the top of the receiver.

Excellent outcome, Dan. And something of an education for most of us too, I would think. Hopefully you are able to rework the existing stator. Go well......)

That's certainly a possibility, Downunder, though I would prefer to be able to fly (locally) with the 2 inner tanks valved on, so avoiding the need for monitoring and valve changes (and relying on the receiver low level switch, which itself is not failsafe). Certainly if I was building again I would run the fuel return to the fuel valve manifold (it's closer than the receiver tank), rather than to the R Inner, though this is only an issue for me when running on the outer tanks with inner tanks fairly full. Otherwise, note that I normally land with the R Inner tank low despite the fact the return line goes to that tank.

1 - A FAILED EXPERIMENT, OR FIX A PROBLEM AND MAKE A PROBLEM: The Savannah has 35Litre Left and Right wing tanks (with sight glasses showing fuel level) feeding a 6Litre receiver tank behind the passenger seat. The receiver tank has a vent pipe to return any air to the top of the L wing tank, ensuring that it remains flooded. The receiver tank is also fitted with a low level switch which makes when the level there drops (to approx 5Litres), lighting indicator/s on the instrument panel. From the receiver tank, the fuel is passed to the engine via an isolator valve and the aux fuel pump etc in the usual fashion, with a return line via a small orifice (as recommended by Rotax) back to the R wing tank. My Savannah has the 2 additional 35Litre 'long range' tanks, so my tanks are L Outer, L Inner, R Inner, R Outer. I have these individually valved at a manifold on the right hand side of the baggage compartment (where I can see them), essentially a copy of Mark Kyle's valving setup. I am very happy with this arrangement. I normally only use the Inner tanks, and we can ignore the outer tanks for the following: I have always had the same uneven fuel take from my tanks, finishing any trip with the R tank 10 to 15Litres lower than the L tank. This did not bother me, as the fuel would take from the L tank once the R tank was down. And I was told that most aircraft have this to some degree. But I have been fiddling with it anyway, and one possibility was uneven fuel tank venting. The standard Savannah tank vents are 4mm airline looped up from the fuel cap and down through the wing, with the open end in the airflow under the wing. I recently saw a new Savannah where these vents were very neatly attached to the underside of the wing and directed forward, like mini-pitot tubes. I set out to copy this, and once I'd worked out how to get a tight bend into the air line without collapsing it, it came together very neatly. Feeling pleased with my neat job, I fuelled up L and R evenly, and set out on a test flight. My intention was to dip the tanks after landing to check again for uneven feed, since the sight glasses slosh around in flight and do not give an accurate picture. However, about half an hour out, I glanced at the sight glasses, and the R one seemed a long way down. Stranger still, the L one seemed a long way up. So I turned round and went home, isolated and dipped the tanks after landing, and sure enough the R tank was way down, while the L tank had more fuel than when I set off. And the reason was clear enough once I got up to dip the tanks: despite the fuel caps feeling tight, there were fuel stains back across the L wing. So my new vent pipes had pressurised the tanks, and since the L cap was not holding that pressure, fuel was feeding from the R to the L tank. I have since returned my vents to straight down (then cut at an angle into wind) rather than facing forward, using the fastenings I had added to hold them there. Thinking it through now, the smallest difference in tank pressure will result in some cross-feeding: running some rough numbers, a pressure difference of just 0.12PSI would be enough to entirely empty one tank into the other. It seems to me it will be much easier to avoid this if vent pressures are reduced.

Yes, looks like the fork has been changed. And as Mark said (above) it's back to front. Looks also as though they adjusted the nose leg length by cutting the original tube, fitting a larger dia tube over it, and sticking a couple of bolts through. Can't see what limits nose suspension travel, normally a couple of rubber bumpers bolted through the nose leg, but maybe they're tucked up out of view. Is that fuselage side to the rear of the firewall ripply, or is that just a trick of the light? Dual brakes, long range tanks and standard paint layout.... Factory build?

Yes, you have it correct!. If you go to Forums here, and scroll down Recreational Aircraft Usergroups, you will find a Savannah forum. It is a wonderful source of information on building and flying the Savannah. And there are always people here happy to help too. All the best with your build.

Hello Lucas, it goes on in the position in the photograph from the manual. In your photographs, it is riveted to the holes above where the clekos are, so it is riveted at the left and right holes there, and sits over the larger hole in the middle. Do you have a Parts Manual? If you buy the kit, you get an Assembly Manual, and also a Parts Manual. The Parts Manual has exploded diagrams of the various assemblies, and is also very useful for checking how the parts go together: I found it useful to work from both manuals during my build.

Lovely........) I don't remember the wing tanks on the ones at Heathrow. I do remember that long nose gear set forward at just the right angle. Whoever designed that aircraft made something very special. Wasn't there a freight version with a reinforced floor...popular latterly in S America for various naughty activities???