---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Sun 06/23/13: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:12 AM - Play in rear sockets (andrew cullum) 2. 01:24 AM - Re: wing lift/drag pins (Bob Harrison) 3. 02:43 AM - Re: wing lift/drag pins (David Joyce) 4. 05:36 AM - tank vent and drain taps (Karl Heindl) 5. 06:48 AM - Re: tank vent and drain taps (Frans Veldman) 6. 07:03 AM - Re: wing lift/drag pins (Brian Davies) 7. 11:46 AM - Re: fuel return line restrictor (Bud Yerly) 8. 12:18 PM - Re: wing lift/drag pins (Bud Yerly) 9. 01:07 PM - Use of reserve tank (graeme bird) 10. 01:28 PM - Re: Use of reserve tank (David Joyce) 11. 01:42 PM - Fort William to Inverness (graeme bird) 12. 02:29 PM - SV: Use of reserve tank (Sidsel & Svein Johnsen) 13. 02:32 PM - SV: Fort William to Inverness (Sidsel & Svein Johnsen) 14. 04:00 PM - Re: tank vent and drain taps (Bob Harrison) ________________________________ Message 1 _____________________________________ Time: 01:12:17 AM PST US Subject: Europa-List: Play in rear sockets From: andrew cullum Hi Sue, Andy Cullum here G-CGDH. I concur with David's reply,it sounds from your description Of the play you describe is produced by ovalled holes fore/aft in the socket shoulders,so it could be you may have To re-new them,it would be interesting to know how many hours your aircraft has flown. Best regards Andy Cullum. Sent from my iPhone ________________________________ Message 2 _____________________________________ Time: 01:24:15 AM PST US From: "Bob Harrison" Subject: RE: Europa-List: wing lift/drag pins Hi! Sue I don't profess to be an authority ....however are there visual signs of any wear in the drag pin and swivels? Is the play identical on both wings ? Are the front lift pins visually worn (or the holes with which they engage ) Are the main spar pins and bushes secure in both the seat backs and spars? Does the spar assembly have a wrap round "cuff" and is it snug to both the spars when assembled ? (best do a trial assembly of the spars and wings clear of the aircraft to see this issue) Is there any free play between the four faces of the ailerons control transfer pads ? Is the main spar pip pin suitably packed out so the pip clamps the starboard spar tip to the aft of port spar and seat back w Get positive answers to all these items and you should be fit to fly. Where do you fly out of? Regards Bob Harrison G=PTAG Kit 337 (1000 Hours) From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of sue hyde Sent: 23 June 2013 07:54 Subject: Re: Europa-List: wing lift/drag pins Many thanks for the reply but I misled you with my description. The play I am talking about can be felt on the tip of the main wings when manouvering the aeroplane and appears to be on the rear drag pin/pip pin area. The socket is secure to the fuselage and the drag pin is secure to the wing. there is just a little play in the swivel of the socket From: David Joyce Sent: Saturday, 22 June 2013, 19:06 Subject: Re: Europa-List: wing lift/drag pins Sue, the socket is able to pivot in a wing flapping mode, but otherwise should be very tight in its fore Nd aft retaining shoulders and they should be absolutely rigidly fixed to the underlying wood & composite mount. It does not sound entirely healthy from your description and I would strongly advise you get an inspector to look at it before you take to the air. Regards, David Joyce, G- XSDJ On Sat, 22 Jun 2013 17:15:15 +0100 (BST) sue hyde wrote: > I have recently purchased a Europa and there is a little for/aft movement on the pip pin socket mount . Is this p; --> http://forums.matronics.com/ sp; bsp; -Matt Dralle, List Ad====== ________________________________ Message 3 _____________________________________ Time: 02:43:24 AM PST US From: "David Joyce" Subject: Re: Europa-List: wing lift/drag pins Sue, Not quite able to picture exactly what you describe, but if in doubt, and in any case with a newly purchased homebuilt plane there is much to be said to having an LAA inspector look it over. You will in any case need to establish a relationship with one to get your maintenance signed off. LAA engineering will give you a list of inspectors or you could ask on this list for recommendations if you give your home area. And while you are at it if you haven't already joined I strongly recommend joining the Europa Club (www.theeuropaclub.org), which offers wide reaching technical support and all sorts of other support. Regards, David Joyce, G-XSDJ On Sun, 23 Jun 2013 07:54:12 +0100 (BST) sue hyde wrote: > Many thanks for the reply but I misled you with my >description. The play I am talking about can be felt on >the tip of the main wings when manouvering the aeroplane >and appears to be on the rear drag pin/pip pin area. The >socket is secure to the fuselage and the drag pin is >secure to the wing. there is just a little play in the >swivel of the socket > > > > ________________________________ >From: David Joyce > To: europa-list@matronics.com Sent: Saturday, 22 June >2013, 19:06 > Subject: Re: Europa-List: wing lift/drag pins > > > > > > Sue, the socket is able to pivot in a wing flapping mode, >but otherwise should be very tight in its fore Nd aft >retaining shoulders and they should be absolutely rigidly >fixed to the underlying wood & composite mount. It does >not sound entirely healthy from your description and I >would strongly advise you get an inspector to look at it >before you take to the air. > Regards, David Joyce, G- XSDJ > > On Sat, 22 Jun 2013 17:15:15 +0100 (BST) > sue hyde wrote: >> I have recently purchased a Europa and there is a little >>for/aft movement on the pip pin socket mount . Is this >>usual?=============== ________________________________ Message 4 _____________________________________ Time: 05:36:43 AM PST US From: Karl Heindl Subject: Europa-List: tank vent and drain taps Having recently re-arranged/replaced all fuel lines=2C vent lines and sight tube I am still at odds with two items: 1. What exactly is the reason again for having the tank vent in the airstre am instead of a static position? Are we doing this because everybody else h as always been doing it or is there a real safety aspect ? I have been give n six reasons=2C but none of them make sense to me and there is no proof. A static vent can handle any air flow in and out of the tank. I don't see th e need for pressurization=2C especially since this must be miniscule=2C in a pump driven system. Maybe in a gravity fed fuel system it might make sens e=2C or where there are two fuel tanks. Some of you have moved the vent to the bottom of the fuselage=2C where it could easily be clogged by mud or in sects. It has happened twice to my pitot tube. 2. Why has no PFA/LAA or other inspector ever pointed out the fact that the drain tap arrangement is completely useless ? There would have to be an aw ful lot of water in the tank before any of it would show up in a drain cup. But it could get to the engine in a steep descent. The obvious reason is th e high point of the fuel exits and the high barb fitting on the taps themse lves. This would be especially so in a mono. The only sensible installation would be flush fitting taps in the tank itself. I am tempted to remove tha t plumbing and use the tap on my mini-gascolator . Karl ________________________________ Message 5 _____________________________________ Time: 06:48:50 AM PST US From: Frans Veldman Subject: Re: Europa-List: tank vent and drain taps On 06/23/2013 02:36 PM, Karl Heindl wrote: > 1. What exactly is the reason again for having the tank vent in the > airstream instead of a static position? Are we doing this because > everybody else has always been doing it or is there a real safety aspect > ? I think it is the first. Especially when you have the tank vent connected to the cobra, there is no risk of sucking the fuel out of the tank even if there would be a negative pressure. > I don't see the need for pressurization, especially since this > must be miniscule, in a pump driven system. In our soft tanks pressurization is even harmfull. It may cause the tank to jam the aileron control, or abrasion of the tank when it repeatedly expands, or other bad things. Best thing would be a neutral or slightly negative pressure (the latter helping to keep fuel fumes out of the cockpit). Like you said, we don't have gravity fuel feed like Cessna's but we are dependant on a fuel pump anyway. > 2. Why has no PFA/LAA or other inspector ever pointed out the fact that > the drain tap arrangement is completely useless ? There would have to be > an awful lot of water in the tank before any of it would show up in a > drain cup. I never got any drop of water out of these drains, and have never heard of anyone else who got any water out of it. (If anyone has, I would like to hear about it, and also whether this water showed up in the gascolator as well). Instead, I think the drains and associated plumbing are increasing the risk of leaks, and are a hazard during an accident: if the gear is ripped off the next thing to contact the ground and be ripped off are the fuel drains, and together with the unavoidable sparks this will for sure trigger a fire. And the drains can not be closed with the fuel valve so there is nothing you can do about it. The next time I will have maintenance on the fuel plumbing I will take the drains out. It is just a matter of judging the safety advantages against the safety disadvantages, and to my judgement the latter puts more weight in the equation here. The only things I found them useful for is for draining the entire tank for maintenance and inspection (I have valves that can be locked in the open position) and to fill the bottle of my camp stove. But all this can also be accomplished by other methods. Avoiding water in the tank can also be accomplished by refueling after each flight so there is only little air left in the tank. Having said that, I was surprised after the winter stop in an unheated barn with only a little fuel in the tanks that despite all the temperature cycles (and associated "breathing" of the tank) and our wet climate that no water at all condensed in the tank, not a single drop! Also, how is this arranged with cars? I have never seen a car with a fuel drain, but yet water in the fuel seems to be unheard off (obvious causes of forgetting to put the cap on the tank not counting). What's the story here? > The obvious reason is > the high point of the fuel exits and the high barb fitting on the taps > themselves. I have copper tubes inside the tank running to a position lower than the fuel outlet for the engine. So in theory it could work. Frans ________________________________ Message 6 _____________________________________ Time: 07:03:33 AM PST US From: "Brian Davies" Subject: RE: Europa-List: wing lift/drag pins Sue, David's advice regarding an LAA inspector is good, especially with a newly acquired aircraft. Having said that, if you move the wing tip back and forth, a few thousandths of an inch play at the rear wing pin will translate to noticeable movement at the wing tip because of the geometry. There must be some clearance or you would not be able to get the pins in or out. My aircraft has been like this from new and I have been unable to find any significant play in any of the fittings. It may not be a problem but it is best to get it checked. Regards Brian Davies G-DDBD -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of David Joyce Sent: 23 June 2013 10:43 Subject: Re: Europa-List: wing lift/drag pins --> Sue, Not quite able to picture exactly what you describe, but if in doubt, and in any case with a newly purchased homebuilt plane there is much to be said to having an LAA inspector look it over. You will in any case need to establish a relationship with one to get your maintenance signed off. LAA engineering will give you a list of inspectors or you could ask on this list for recommendations if you give your home area. And while you are at it if you haven't already joined I strongly recommend joining the Europa Club (www.theeuropaclub.org), which offers wide reaching technical support and all sorts of other support. Regards, David Joyce, G-XSDJ On Sun, 23 Jun 2013 07:54:12 +0100 (BST) sue hyde wrote: > Many thanks for the reply but I misled you with my description. The >play I am talking about can be felt on the tip of the main wings when >manouvering the aeroplane and appears to be on the rear drag pin/pip >pin area. The socket is secure to the fuselage and the drag pin is >secure to the wing. there is just a little play in the swivel of the >socket > > > > ________________________________ >From: David Joyce > To: europa-list@matronics.com Sent: Saturday, 22 June 2013, 19:06 > Subject: Re: Europa-List: wing lift/drag pins > > > > > > Sue, the socket is able to pivot in a wing flapping mode, but >otherwise should be very tight in its fore Nd aft retaining shoulders >and they should be absolutely rigidly fixed to the underlying wood & >composite mount. It does not sound entirely healthy from your >description and I would strongly advise you get an inspector to look at >it before you take to the air. > Regards, David Joyce, G- XSDJ > > On Sat, 22 Jun 2013 17:15:15 +0100 (BST) sue hyde > wrote: >> I have recently purchased a Europa and there is a little for/aft >>movement on the pip pin socket mount . Is this usual?=============== ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 7 _____________________________________ Time: 11:46:53 AM PST US From: "Bud Yerly" Subject: Re: Europa-List: fuel return line restrictor Rowland, I noticed the same thing a couple months ago installing Jeff Robert's new engine. Rotax now uses the .35 mm and our FS02 is .025 inches or .7mm. My A&P researched the difference with Lockwood and I did it through Rotech. We asked if we needed to change. They didn't care. The fuel pump (mechanical) has been changed slightly and as usual Rotax never bothered to explain the difference in flow and performance. We were told to expect slightly higher fuel pressures with the new restrictor mounted on the fuel split fitting. Basically if the fuel pressure is between 2.2 min and 5.8 max fine. No optimum is set by Rotax at max power at sea level that I have found. As for flow you will see no difference since the carbs are using the fuel based on the need of the engine, not the pressure in the fuel line. The float needle cuts off the flow to the carb. The flow back through the return line will be that volume of fuel which is unused. Regardless of pressure (provided it is within limits.) Only if the float needle sticks open will you see a significant difference in flow (and of course engine performance). Other detail: We did a test using the supplied Rotax restrictor on the new 912S vs our old FS02. Fuel pressure dropped a bit with the FS02 but did not get anywhere near the 5.8 max of the fuel pressure with both pumps running and was above the 2.2 min with just the engine pump and when pulling the fuel line off the engine pump and putting only the electric pump into action it was still above the min. We saw a bit of an increase with the smaller fuel restrictor of .3 psi. on our old hand held pressure gauge. We were still getting 3.2 psi with the FS02 and 3.5 with the Rotax (as measured with my really old gauge which was calibrated three years ago to 3 psi or 83 in. H2O) so not much difference (Jeff's electric gauge was about 4 psi with the Rotax engine pump and a bit lower on the electric pump. The manufacturer of the aircraft is responsible for his setting up of the fuel system. If the FS02 works within limits, why change it. Kerry at Lockwood is ambivalent about the difference. He has found some builders who weren't using restrictors at all and the 912S ran fine on high wing aircraft (Rans S 6). No report on the low wing aircraft, they all had restrictors supplied by the kit manufacturer or Rotax. If it is within limits, at full power, it is within limits. In the US we don't have to do fuel flow tests, but to check you just need to put a clear tube inline on the return side and look at the flow or collect it into a measuring cup. If the pressure in the line with the FS02 is only .3 psi different, then the higher pressure of the Rotax orifice will flow faster through the orifice but the flow will be the same as with the FS02. Pump volume makes a huge difference in return flow. Nice of Rotax to change the pump slightly without providing tests and results. Note that the wrong auxiliary pump (such as the automotive low pressure style, like the Facet or Purilator 4104/5) will make a difference as they don't provide the volume. Years ago Europa did SB 04 specifying the Facet 40106. Only if one installs a restrictive fuel supply system by using a small diameter fuel selector, fuel filter, gascolator, etc. will there be a problem. Keep the fittings and fuel selectors as specified and the Europa fuel system works well. The LAA requirement for excess fuel flow check is a great idea on an untried engine/fuel system, but on a tried and true design it is just scary as hell and a bit noisy and tedious. We just empty the pax side of the tank, and run the engine checks on the main and note that the fuel returns to the tank and then fiddle with the fuel flow on the Dynon or EIS until close to 7 GPH. After about 15 minutes of running, you will see a small amount of fuel in the reserve or pax side and have a fuel flow that is fairly close for initial cruise checks. Pretty stupid and lazy and not very scientific of us, but that is all we have ever needed. At my shop we check that the fuel pressure is in the range with only one pump and does not exceed the max with both on. We have never had a problem with the min pressure. Our US DARs don't care as long as full power runs have been made and the kit system is installed as per the manufacturer of the kit. If the kit manufacturer does not specify a fuel system, a good DAR will want evidence of a full power run only, but no excess fuel flow requirement is set. We are at sea level so the fuel flow should be at its max with the prop set to 5200-5600 RPM at full throttle. My DAR and FSDO are happy with that. Best Regards, Bud Yerly ----- Original Message ----- From: Rowland Carson To: Europa e-mail list list Sent: Friday, June 21, 2013 1:19 PM Subject: Europa-List: fuel return line restrictor > While delving into the various Rotax manuals in pursuit of information about the fuel manifold, I noted the dimensions of the restrictor in the fuel return line - 0.35mm ID. I have been considering the most elegant way to incorporate the restrictor supplied by Europa (FS02) into my home-brewed alternative to the Rotax manifold and so checked its dimensions. I find that the restrictor hole will easily pass a number 71 drill bit, but barely accepts the shank of a number 70 drill bit. So I deduce that the orifice is about 0.7mm ID, ie twice the diameter of the Rotax one. Why should Europa have supplied a different size of restrictor from that called out by Rotax? Looks as though the Rotax orifice will (in any otherwise identical circumstance) allow the fuel pressure to build up slightly higher, and return less fuel to the tank, than the Europa one. It might just make the difference between pass and fail in a fuel flow test. Has anyone had any issues traceable to this difference between the Europa-supplied restrictor and the Rotax one? I might consider machining up my own manifold (obviously I'm heading into deep water with LAA engineering here) and if so, which size of orifice should I incorporate? Should it be removable, rather than integral, to allow fine-tuning of fuel pressure? in friendship Rowland | Rowland Carson ... that's Rowland with a 'w' ... | > http://www.rowlandcarson.org.uk | Skype, Twitter: rowland_carson Facebook: Rowland Carson | pictures: http://picasaweb.google.com/rowlandcarson http://www.matronics.com/Navigator?Europa-List http://www.matronics.com/contribution ________________________________ Message 8 _____________________________________ Time: 12:18:52 PM PST US From: "Bud Yerly" Subject: Re: Europa-List: wing lift/drag pins Sue, I agree with the guys... When in doubt, have the pin and socket measured and checked. In some aircraft the builder would find that by reaming the hole, the wings rigged easier. Of course, over time the pin could move a bit and as a result the pin and socket can wear a bit more over time. In a properly built Europa the wing will move fore and aft a bit at the tip because the front pin is not up hard against its socket and the spar does bend a bit. However, you should not be able to see the pin move in the socket when an assistant moves the wing tip. If the pin moves enough in the socket that you can see it, you may in fact have either a worn wing pin hole, pip pin or socket hole. I strongly recommend you remove the wings and use a micrometer and check the wing pin hole, pip pin and socket hole for wear. I would think that it should be no more than a 3-4 thousandths difference from 1/4 inch pin and 1/4 inch holes (the mil spec pin diameter is .2485 inches and the balls go out to .289 inches). So 7-8 thousandths total slop is about your normal tolerance for a proper fit between the three items. Any more and the pin starts getting pretty sloppy and the pin holes or the balls on the pip pin could be compromised. Just check it and be sure. It is not hard to change out the wing pin, pip pin or socket hole. Regards, Bud Yerly ----- Original Message ----- From: David Joyce To: europa-list@matronics.com Sent: Sunday, June 23, 2013 5:42 AM Subject: Re: Europa-List: wing lift/drag pins > Sue, Not quite able to picture exactly what you describe, but if in doubt, and in any case with a newly purchased homebuilt plane there is much to be said to having an LAA inspector look it over. You will in any case need to establish a relationship with one to get your maintenance signed off. LAA engineering will give you a list of inspectors or you could ask on this list for recommendations if you give your home area. And while you are at it if you haven't already joined I strongly recommend joining the Europa Club (www.theeuropaclub.org), which offers wide reaching technical support and all sorts of other support. Regards, David Joyce, G-XSDJ On Sun, 23 Jun 2013 07:54:12 +0100 (BST) sue hyde > wrote: > Many thanks for the reply but I misled you with my >description. The play I am talking about can be felt on >the tip of the main wings when manouvering the aeroplane >and appears to be on the rear drag pin/pip pin area. The >socket is secure to the fuselage and the drag pin is >secure to the wing. there is just a little play in the >swivel of the socket > > > > ________________________________ >From: David Joyce > > To: europa-list@matronics.com Sent: Saturday, 22 June >2013, 19:06 > Subject: Re: Europa-List: wing lift/drag pins > > >> > > > Sue, the socket is able to pivot in a wing flapping mode, >but otherwise should be very tight in its fore Nd aft >retaining shoulders and they should be absolutely rigidly >fixed to the underlying wood & composite mount. It does >not sound entirely healthy from your description and I >would strongly advise you get an inspector to look at it >before you take to the air. > Regards, David Joyce, G- XSDJ > > On Sat, 22 Jun 2013 17:15:15 +0100 (BST) > sue hyde > wrote: >> I have recently purchased a Europa and there is a little >>for/aft movement on the pip pin socket mount . Is this >>usual?=============== http://www.matronics.com/Navigator?Europa-List http://www.matronics.com/contribution ________________________________ Message 9 _____________________________________ Time: 01:07:22 PM PST US Subject: Europa-List: Use of reserve tank From: "graeme bird" First sorry I didn't make it to the UK AGM - too windy for me. I mentioned in my Gumpy Scotland post that I landed with 11 litres remaining. That was the reading on my FP-5L and I was able to put in 57 litres of fuel and so it was confirmed. I was tempted to switch to reserve on approach for a sure 9 ltrs or so hopefully there. I didn't but I was ready to switch. Opinions? Also I wondered how much would be on the reserve side after a few (gentle)turns. I guess you would actually have a bit longer on main and less than expected in reserve. Also I filled to the top, I cant recall if the 68ltrs included the neck etc (Mono rubber style. -------- Graeme Bird G-UMPY Mono 912S/Woodcomp 3000/3W Newby: 55 hours 1 year g(at)gdbmk.co.uk Read this topic online here: http://forums.matronics.com/viewtopic.php?p=403228#403228 ________________________________ Message 10 ____________________________________ Time: 01:28:27 PM PST US From: "David Joyce" Subject: Re: Europa-List: Use of reserve tank Graeme, I measured my reserve long ago as having 11 litres useable in it, a comfortable 1/2 hr reserve. It shouldn't make any difference if you do turns (or even a loop!) as they should be balanced so that neither you nor the fuel wants to slide off to one side, but on top of that while you are on main the reserve is constantly being topped up by the return line. I have a low pressure warning light and on several occasions I have flown until the main ran dry. This put my light on, fairly soon followed by the engine running a bit hesitantly! but with either the light or the hesitation giving enough time to switch to reserve and carry on normally. You would probably not want that to happen at a critical stage of a demanding landing so switching to reserve if you are close to running out makes excellent sense if about to land. If you find yourself having to do several go arounds and you cough on reserve, you can always switch back to main! regards, David Joyce, GXSDJ On Sun, 23 Jun 2013 13:06:56 -0700 "graeme bird" wrote: > > >First sorry I didn't make it to the UK AGM - too windy >for me. > > I mentioned in my Gumpy Scotland post that I landed with >11 litres remaining. That was the reading on my FP-5L and >I was able to put in 57 litres of fuel and so it was >confirmed. > > I was tempted to switch to reserve on approach for a >sure 9 ltrs or so hopefully there. I didn't but I was >ready to switch. Opinions? > Also I wondered how much would be on the reserve side >after a few (gentle)turns. I guess you would actually >have a bit longer on main and less than expected in >reserve. > > Also I filled to the top, I cant recall if the 68ltrs >included the neck etc (Mono rubber style. > > -------- > Graeme Bird > G-UMPY > Mono 912S/Woodcomp 3000/3W > Newby: 55 hours 1 year > g(at)gdbmk.co.uk > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=403228#403228 > > > > > > > >Un/Subscription, >Forums! >Admin. > > > ________________________________ Message 11 ____________________________________ Time: 01:42:18 PM PST US Subject: Europa-List: Fort William to Inverness From: "graeme bird" It would seem a that flying up the valley between Fort William to Inverness from the sea would seem a sensible route north through the Scottish Highlands. Is this a familiar route to anyone? -------- Graeme Bird G-UMPY Mono Classic/XS 912S/Woodcomp 3000/3W Newby: 75 hours 18 months g(at)gdbmk.co.uk Read this topic online here: http://forums.matronics.com/viewtopic.php?p=403233#403233 ________________________________ Message 12 ____________________________________ Time: 02:29:51 PM PST US From: "Sidsel & Svein Johnsen" Subject: SV: Europa-List: Use of reserve tank Graeme, What we need to keep in mind is the following: When we run off the main tank, about 28-30 liters of fuel goes out per hour at cruise power (912ULS). Abt 10 of these liters return to the reserve tank (i.e. abt 1/3 of the total flow out of the tank), and flow back over the saddle into the main tank. This ensures that the reserve tank is always full, even if we should fly a little uncoordinated once in while or experience some bumpy turbulence, and the net drain from the main tank is 18-20 liters (or whatever the cruise consumption may be). What we should NOT do is switching to the reserve tank before we have decided that "OK, this is it for the main tank, from now on it's only the reserve tank that will take me home." Take the following case: 9 liters in the reserve, 11 liters in the main. If this were the case during the last part of a flight, we have 20 liters total, i.e. one hour's flying time. If due to uncertainty about actual volume remaining in the main tank, we switch to the reserve tank (9 liters), then we have a little under half an hour before the engine tells you something. If we now switch back to the main tank, we suddenly do not have 11 liters consumable fuel there anymore! Why not? Because about 1/3 of that fuel is returned to the reserve tank, but the returned volume does not any more overflow into the main tank because the reserve tank first needs to be filled to its top. 10-15 minutes' flying time is thus lost, which could be critical (unless we are conscious about this, and switches back to reserve again). What it all boils down to is knowing how much you have left in the main tank, so we can confidently run this tank almost empty and switch to reserve just in time before the engine tells you to, and then stay on the reserve tank. I completely trust my fuel totalizer (feed and return flow senders) and the sight tube. By the way, I have connected the two vent tubes (the one from the top of the sight tube and the one to the top of the filler neck) by a crossover tube at their highest point. If one inlet should be blocked by an insect or whatever, the other will provide equal pressure on top of the tank and on top of the fuel in the sight tube. It is amazing how erroneous the sight tube reading gets even with a very small pressure difference in the standard tubing arrangement - just try it by blowing gently into one of the outlets. ///////// About return flow: I mentioned early this spring that I would re-wire the fuel flow system so that I could get temporary direct reading of the return flow only. I have the relay deck and the push button, but just have not had the time to wire it in ........ Will do - will report! Regards, Svein LN-SKJ ________________________________ Message 13 ____________________________________ Time: 02:32:51 PM PST US From: "Sidsel & Svein Johnsen" Subject: SV: Europa-List: Fort William to Inverness Graeme, I have done it - in both directions - with my sailboat on the Caledonian Canal. I can only imagine how beautiful it may be from the air - do it! Regards, Svein LN-SKJ > > It would seem a that flying up the valley between Fort William to Inverness > from the sea would seem a sensible route north through the Scottish > Highlands. Is this a familiar route to anyone? > > -------- > Graeme Bird > G-UMPY > Mono Classic/XS 912S/Woodcomp 3000/3W > Newby: 75 hours 18 months > g(at)gdbmk.co.uk > ________________________________ Message 14 ____________________________________ Time: 04:00:09 PM PST US From: "Bob Harrison" Subject: RE: Europa-List: tank vent and drain taps Hi! Franz/all. I can confirm that Once in particular when parked overnight at ZelamZee in a particularly violent down pour I emptied about half a litre of water from one of my water drain taps . Since then I have tried to ensure that the whole tank filler cap is blanked off by tape especially the lock. I do have a mop out access hole in the tank top and most winter grounding periods I drain out and mop out to ensure both tanks are started with a clean charge of fuel. I have also occasionally had small amounts of water show depending on the level parking of the aircraft too. Regards Bob Harrison G-PTAG -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com] On Behalf Of Frans Veldman Sent: 23 June 2013 14:48 Subject: Re: Europa-List: tank vent and drain taps --> On 06/23/2013 02:36 PM, Karl Heindl wrote: > 1. What exactly is the reason again for having the tank vent in the > airstream instead of a static position? Are we doing this because > everybody else has always been doing it or is there a real safety > aspect ? I think it is the first. Especially when you have the tank vent connected to the cobra, there is no risk of sucking the fuel out of the tank even if there would be a negative pressure. > I don't see the need for pressurization, especially since this must be > miniscule, in a pump driven system. In our soft tanks pressurization is even harmfull. It may cause the tank to jam the aileron control, or abrasion of the tank when it repeatedly expands, or other bad things. Best thing would be a neutral or slightly negative pressure (the latter helping to keep fuel fumes out of the cockpit). Like you said, we don't have gravity fuel feed like Cessna's but we are dependant on a fuel pump anyway. > 2. Why has no PFA/LAA or other inspector ever pointed out the fact > that the drain tap arrangement is completely useless ? There would > have to be an awful lot of water in the tank before any of it would > show up in a drain cup. I never got any drop of water out of these drains, and have never heard of anyone else who got any water out of it. (If anyone has, I would like to hear about it, and also whether this water showed up in the gascolator as well). Instead, I think the drains and associated plumbing are increasing the risk of leaks, and are a hazard during an accident: if the gear is ripped off the next thing to contact the ground and be ripped off are the fuel drains, and together with the unavoidable sparks this will for sure trigger a fire. And the drains can not be closed with the fuel valve so there is nothing you can do about it. The next time I will have maintenance on the fuel plumbing I will take the drains out. It is just a matter of judging the safety advantages against the safety disadvantages, and to my judgement the latter puts more weight in the equation here. The only things I found them useful for is for draining the entire tank for maintenance and inspection (I have valves that can be locked in the open position) and to fill the bottle of my camp stove. But all this can also be accomplished by other methods. Avoiding water in the tank can also be accomplished by refueling after each flight so there is only little air left in the tank. Having said that, I was surprised after the winter stop in an unheated barn with only a little fuel in the tanks that despite all the temperature cycles (and associated "breathing" of the tank) and our wet climate that no water at all condensed in the tank, not a single drop! Also, how is this arranged with cars? I have never seen a car with a fuel drain, but yet water in the fuel seems to be unheard off (obvious causes of forgetting to put the cap on the tank not counting). What's the story here? > The obvious reason is > the high point of the fuel exits and the high barb fitting on the taps > themselves. I have copper tubes inside the tank running to a position lower than the fuel outlet for the engine. So in theory it could work. Frans ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/europa-list Browse Digests http://www.matronics.com/digest/europa-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.