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IBob

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Everything posted by IBob

  1. IBob
    Marty, it's pretty straightforward: You know the height difference between your tanks and the receiver tank behind the seat. You've got your fittings. Get the hose you're looking at using, and the fittings and set it up at those heights on the bench, with some sort of vessel at the top, and another at the bottom. Put in a known amount of fuel and time how long it takes to arrive. Online calculators are more normally used for longer runs of larger pipe at higher pressures, all sitting on the ground. They're good for sizing that sort of thing up. But in an aircraft, you're looking for the reasonable minimum (weight) that will do the job in practise. So, you're not looking for opinions, or for theoretical answers. You're looking for a practical answer as to whether your aircraft fuel system will deliver through 1/4" pipe fittings. And you check that by trying it.
  2. IBob
    First fly since lockdown (it lifted a week ago but wx has been marginal and I've been helping with a build). After 5weeks, the engine would not initially fire at all: it took 3 sustained crankings of 7 or 8 sec with breaks in between plus cycling of the fuel pump. This was a first for this engine: in 180hrs of operation it has always started just about instantly. At a guess I would say very stale fule in the carb bowls? Once it did fire it vwas business as usual. So, a few circuits to make sure the feet still work, then a short flight over towards the ranges: this is one of many river valleys in the foothills. Broken cloud, base approx 2000', stayed under dodging light showers, carb heat on to avoid icing (the online time I've ever had this engine cough was flying up under cloud base.)
  3. IBob
    That red Sav must have been very naughty indeed to be kneeling in the corner like that......(
  4. IBob
    On the Sav, the breather goes into a point high in the side wall of the LH (inboard) tank: it has it's own fitting there. (I guess it could also be teed into the upper sight glass fitting, provided that tube was level or uphill from the tee to the tank, that would be one less fitting in the tank.) On the pics the RH top tube is the fuel coming in, the LH top tube is the breather. The breather pipe does a a very tight bend under the mixer, that steel pipe is excellent as it holds the bend you put in it, and bends without collapsing. You can also see the low fuel switch wiring lug riveted to the crossmember in the bottom pic. And the cable run in the black corrugated stuff at the base of the tank in the second pic down is the main battery + and - cables and the lead from the low fuel switch going forward. The other visible wiring is from the Magnum box to the wingtip strobes.
  5. IBob
    On the Sav, the breather goes into a point high in the side wall of the LH (inboard) tank: it has it's own fitting there. (I guess it could also be teed into the upper sight glass fitting, provided that tube was level or uphill from the tee to the tank, that would be one less fitting in the tank.) On the pics the RH top tube is the fuel coming in, the LH top tube is the breather. The breather pipe does a very tight bend under the mixer, that steel pipe is excellent as it holds the bend you put in it, and bends without collapsing. You can also see the low fuel switch wiring lug riveted to the crossmember in the bottom pic. And the cable run in the black corrugated stuff at the base of the tank in the second pic down is the main battery + and - cables and the lead from the low fuel switch going forward. The other visible wiring is from the Magnum box to the wingtip strobes.
  6. IBob
    Just sits on floor skin, no reinforcing, upper part is strapped to panel behind RH seat. Haven't seen one with 3 top fittings. Maybe one for each of the tanks, and the small one added later as a breather. On the Sav the breather goes into the LH inboard tank high up (and the fuel return from engine goes same place on the RH tank.) Having said that, no need for 3 fittings: normally one big one is used to bring fuel in from 1 or multiple tanks, the other big one is the breather. The low fuel switch is a simple reed switch, and when it is made (fuel low) it connects the wire to the aircraft hull. So that terminal there is normally riveted to the hull right next to the tank. The indicator at the panel has 12V on it all the time, the level switch completes the circuit by switching on the negative side. The indicator test button on the panel does the same thing: completes the circuit on the negative side. Not the best pics, sorry.
  7. IBob
    RFguy, if it hasn't been touched on here before: have you checked that your callipers are floating properly, so the pads are pressing fully on both sides of the disks? The brakes on my aircraft are very basic, the float is provided by dowels that are a very neat fit, with no way of cleaning or lubricating without dismantling. And float can be hard to check too: the brake can look okay with pads on both sides contacting the disk even if the calliper is no longer floating. So far, my braking is excellent, but if it starts to fade that will be the first place I will be looking.
  8. IBob
    Indeed. We have long since reached peak amaze. Which would be amazing if there was any amazement left in us........)
  9. IBob
    You'd want to be confident the lines weren't painted on the road after a Friday lunchtime or on a Monday morning..........
  10. IBob
    I like the sound of your auto fuel pump, Mark. I would suggest the pump still needs to be started then stopped in manual prior to engine start and auto operation: (Part of my) prestart goes like this: 1. Check tank levels. 2. Check all fuel valves and isolator are set as required. 3. Master switch on. 4. Fuel pump on: check fuel pressure rises > 2PSI. 5. Fuel pump off: check fuel pressure falls to 0. This checks that the fuel return, which has a very small orifice, is not blocked. The fuel return is essential to avoid the possibility of vapour lock in the fuel delivery system. Since the fuel pump has a built in check valve, if the fuel return is blocked the pressure will not fall when the pump is turned off prior to engine start.
  11. IBob
    Watching this with interest, Mark. I have a Sav to wire somewhere down the track.
  12. IBob
    There was a corkscrew tunnel entrance onto a bridge in Brisbane back in.......um........the 70s. I think it was 270deg, or a 3/4 turn, and I don't know if it got tighter as you went round, but I do know that there were multiple tyre marks well up the outside wall by the time you got towards the other end....
  13. IBob
    Whattttttttttttttttttttt???????????????????????????????????? Dammit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  14. IBob
    Looks great, Marty! Will there be pushbutton to test low fuel indicator, and battery discharge light?
  15. IBob
    Plus one for that. Cheap as chips from Jaycar in various diameters and does a great job of tidying it all up. Mine are cable tied at the floor below the front of the doors, and they don't shift at all.
  16. IBob
    Hi Blueadventures, I struck exactly the same thing on my Sav S build. In my case the slop was in the holes in the control stick, not in the bush that passes through the torque tube. A mate here turned up a couple of little top-hat bushes and we drilled out the holes in the control stick to take them. I wonder if this is the result of using 'almost the same but not quite' metric drills for holes that take imperial AN bolts........
  17. IBob
    C'mon guys: plastic bottles with large diameter tops that nevertheless seal tight when the cap is on are available in any gas station. Just tip out the lurid chemical that some eejits mistake for 'drink' and stow within arm's reach.........)
  18. IBob
    Perhaps these were some of the awful decisions about what is for the greater good, that we all hope never to face, but that sometimes have to be made in wartime. For example: As we now know, the Allies learnt to crack the (shifting) coded messages from the Enigma encoding machine, used for critical communications by the German military. The dilemma then was how to use that information without alerting the Germans to the fact that their comms were not secure. One common rumour after the war was that the war office knew of the upcoming air raid that blitzed Coventry, but chose not to alert the populace for this reason. Whether this is true, I have no idea. But it certainly seems possible.
  19. IBob
    Hi Marty, we were discussing 912 starts while working on a build yesterday: The combination of your positive and negative wiring, and the soft start (timed spark retard period) on your engine should give you prompt and faultless starts every time. It works so well, in fact, that the day I get any hesitancy or misfiring on a start will be the day I go looking for the problem.
  20. IBob
    True enough. But you don't think the Gestapo were seen as dealing with the Jewish?
  21. IBob
    I have no idea when the tide changed, but certainly prior to WW2 a significant number of privileged people in Allied countries were pro-fascist and also anti-semitic. This included the likes of aviator Charles Lindbergh, Dame Lucy Houston (who wrote a check for 100,000pounds to support the Schneider Trophy effort when the British government would not, as a deliberate snub to the Labour government of the time), and Edward VIII who abdicated. I don't know whether or how much this may have been the case in Australia and NZ.
  22. IBob
    We're locked down right now, but here's a couple of shots from a flight earlier in the month: the ranges approx 4500ft with a little snow on them to the west of Hood aerodrome in the N Island of NZ. When the westerlies push the clouds over and down, we stay away, but that day was perfect for cruising along the snow line........
  23. IBob
    Mine is on a lug on the starter motor case.
  24. IBob
    Yep, provided there is enough cable to route it so that you can secure it to the engine mount etc. I'm amazed at some of the pics we occasionally see of wiring trailing loose around engine compartments: seems to me that's asking for a break or a short due to vibration and chafing.......
  25. IBob
    Is this it? My yellow alternator wires come up to a connector. This has a mating connector, and the wires from that then go up to the regulator. That's the connector, cable tied down and together at lower centre of the pic:
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