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IBob

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Everything posted by IBob

  1. The boost pump raises the pressure further, so certainly will improve the reading. I'm not saying the gauge is the problem, I'm saying it's the way it is hooked up: it's a differential gauge, close off the atmosphere side, and this is what you get. And nobody so far mentioned altitudes or circuits. I just worked an example.
  2. Come at it another way: 912 min fuel pressure 2PSI More normally it is between 2 and 4PSI, I think. The pressure gauge is differential, fuel pressure one side , atmosphere the other. If the atmosphere side is blanked off in some way, that side remains at ground pressure. If you then take the aircraft to 5000', the outside air pressure...and the actual fuel pressure....is reduced by approx 2.5 PSI. So your fuel pressure will appear to have dropped by that much.
  3. You might not think, Nev..........but I've now seen this twice with 912 installations.
  4. Skippy, with a mechanical gauge, this is exactly the result you get when the builder has forgotten to take the little shipping plug out of the body of the gauge: so the gauge internals stay at ground pressure, while the fuel pressure does actually fall with altitude. So: whatever the fuel pressure sensor is, it should have fuel line on one side, and be open to atmosphere on the other. That's where i would be looking.
  5. Me too, Student Pilot......)
  6. Right, well, my view is this: When it comes to ditching there is a fair bit of theory and speculation, but not a lot of what one could call hard data. By digging back into what data from actual events he could find, and extracting some stats, I think that Bertorelli has helped shed some real light on the subject.
  7. Well, Nev, if you have insights not touched on in the thread so far, could you please share them?
  8. Maybe so, Nev. But for those of us flying light aircraft, and sometimes over water, I would say it gives valuable insight.
  9. And a good segment from Paul Bertorelli:
  10. Student Pilot, here ya go: https://www.aviationsafetymagazine.com/features/the-myths-of-ditching/
  11. Who..............wants ta know?????????????? I'm distinctly average........but with a few outstanding bits.........)
  12. Oo...ouch! ...................)
  13. M.........while all this has been going on I have put 20L across 2 tanks, the old fashioned way and been out flying.......twice!
  14. Sorry, should have been 294joules (so yes, brain is clearly Christmas fried). But still a huge disparity..........
  15. Did a few numbers, and now trying to make sense of them: To lift 1Kg 1m takes 9.8joules. 20L petrol = approx 15Kg So to lift 20L of petrol 2m theoretically takes 29.4joules. All very well in theory. A single AA cell supposedly packs 9,000joules. (and a single alkaline D cell something like 72,000joules) So no problem, right? Flip now to spec of Easyflow battery powered pump listed earlier in this thread. This uses 4 x AA cells, and is sold as a transfer pump (not a lifting pump). And claims to transfer 400L on one set of batteries. That number doesn't seem unreasonable to me. But given the disparity between that and the theoretical numbers, there must be huge inefficiencies and losses somewhere. Or maybe what's left of my brain just shut down for Christmas.......(
  16. My thought exactly........)
  17. The spec says the batteries are good for 400L I think.
  18. Now that looks to be a step in the right direction! I note that it is shown transferring fuel between 2 containers at approx the same level. The spec makes no mention as to how it would perform if pumping 'uphill'. Garfly, do you use yours with the can next to the filling point, or are you pumping from ground up to the wing? And if so, how well does it go, and how long do the batteries last?
  19. One of the main jump centres in the UK had one in the late'70s. I was part of a load of ballast used to demonstrate it to visiting military on a very windy day, so we didn't jump, but went up then came down near vertical in the thing, all jammed against the back of the pilot's seat. The military didn't buy, but we enjoyed the ride. Evidently they are quite heavy on the controls and tiring for the pilot to operate, certainly as a jump ship. That one came to a sticky end when a pilot inadvertently selected beta pitch shortly after takeoff.....(
  20. Pmccarthy I fuel using a 20L container with one of those bendy corrugated spouts. I lift the full container onto the top of the steps and swipe the bottom edge with my hands to make sure it has not picked up any dirt or grit. I then lift the container onto the wing and rest it, tilted on the skin over the main spar. Positioning it to allow max eventual tilt, I bend over the nozzle to point at the funnel and tilt further to start the flow, increasing the tilt until the nozzle is well into the funnel. This allows me to transfer approx. 10L to one tank, and with no spillage. I then repeat the setup at the other tank, but in this case I have to lift the tank (instead of resting it tilted on the wing) to get enough tilt. I usually brace an elbow over the mainspar to steady my hold, and I do sometimes get a small amount of splash onto the wing when the flow first starts. Once in position and filling, I have no other spillage. I'm not particularly strong in shoulders or arms, initially I thought I would have a lot more trouble with this than I now do (though I have certainly had the occasional larger splash). I find the bendy nozzle is a big help. I use a cheap plastic funnel about 140mm dia. I'm sure the small Mr Funnel would be more challenging for that second tank. I wonder if the 20L container might almost be easier to handle in some ways?
  21. AUTO CARB HEAT: The Savannah XL and S take air in to the airbox via a NACA scoop on the top of the cowling. The airbox has a temperature probe, and I noticed that in a hard climb, the airbox temperature would rise. The reason was that the increased angle of attack altered the airflow through and round the cowling with warm undercowl air being taken at the 20-25mm gap between the NACA scoop fibreglass and the airbox inlet, instead of cold air from the NACA scoop. This was easily fixed by extending the airbox inlet with an aluminium tube, held in place with a hose clamp. I left a gap of approx 3mm to allow drainage in the event of rain while parked. The extension is marked with a black felt pen line at the RH end of the airbox. (The scat tube is warm air from the muffler for those times when you do actually want carb heat).
  22. Ah, gotcha. The Savannah 'carb heat' just takes air from over the muffler into the airbox, so is divorced from other systems and not at risk of complicating them.
  23. Hi Brendan, we had a club Tecnam make a forced landing here some time ago. Very experienced pilot, long descent to finals, I think, started running horribly rough so he set it down. Started and ran no problems thereafter, no fault found and subsequently returned faultlessly to club use, so high likelihood it was icing. The aircraft I mentioned on short finals was a Savannah, they take air from outside the cowl, the pilot described it as being like the engine wanted to leave the aircraft. Selecting carb heat in my Savannah certainly results in reduced power, I wouldn't call it negligible. As for the kiss principal, you are in no way complicating anything by having heating available, as most of the time you won't be using it. So I don't see the advantage of kiss here. What it is is an option that's very nice to have on the day that your engine starts to cough and run rough...
  24. What RFguy said. If you have the option, there is no way I would leave it out, Danny. I've had icing cruising just below low cloud level in mild weather (figures!) and I know of another member here had icing on finals, which is exactly when you don't want it. FWIW the Sav has an airbox temp sensor and if in doubt, I now follow the advice of the second example above, by keeping the airbox temp not less than 20'C.
  25. That is a low figure, but i'll certainly buy it. If the prop pitch is perhaps a bit on the fine end of the climb/cruise compromise and and it's flown quietly.
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