Another NEW Savannah XL on its way

[Kyle Communications]

The latest S version also has a internal plate in the tunnel...you can see the rivets in the picture of IBobs one.

 

 

[IBob]

Hi Mark, to complete the picture: the parcel shelf where the top seatbelt fastening is attached has stiffeners from front to back, laterally and also diagonally at the ends. And behind the lateral stiffener (only just visible in the pics) is a further lateral stiffening plate that the seatbelt bolt passes through.

 

I dropped a bolt in the seatbelt hole to try and make it more obvious.

 

 

 

 

[Flyingphot]

Hi Mark The manual for the "S" model dated Nov 2014 still called for rivets only so those aircraft are not wrong. If they required changing ICP would have sent out an AD to all users. That said it is obviously an improvement and I will be incorporating it in my building and rebuilding from now on. Must be safer if the seat belts are ever used in anger. Cheers Bill

 

 

[Kyle Communications]

Hi Bill

 

The pictures in the manuals are wrong BUT the hand done drawings beside them are actually correct...my S manual and my XL manuals are both the same

 

 

[IBob]

Hi Mark The manual for the "S" model dated Nov 2014 still called for rivets only so those aircraft are not wrong. If they required changing ICP would have sent out an AD to all users. That said it is obviously an improvement and I will be incorporating it in my building and rebuilding from now on. Must be safer if the seat belts are ever used in anger. Cheers Bill

Hi Flyingphot

 

My S manual, dated Dec 2014 has a photo in the Cockpit section, Chapter 17 Page 22, Picture No 27 showing SF302 with three A5 rivets and two AN3-05 bolts, one at either end, and with those parts labelled for emphasis.

 

There is also a quick description, saying the same thing.

 

 

[Kyle Communications]

I have another project added to my list

 

Fuel amount has always been a pain thats why I have 4 sight tubes. Belite do a really nice fuel sender but by the time you buy it and the display its like US$600 for one unit. I have been seaching for a manufacturer of pressure sender units that measure small amounts of pressure. I have found one that makes a fully sealed sender that will do 10kpa which is 1.5psi. Its a 4-20ma output so it goes to a pcb that powers the sender and also measures the value then sends it off in I2C format which can be read by a small micro then I can display it on maybe a Oled display or even a touch screen.

 

The sender is not approved for ATEX but thats pretty much a OH&S crock anyway. It will handle gasoline all day as it does not have any Oring seals its a super thin stainless steel bellows.

 

The idea is to have it at the bottom of the sump outlet this will measure then the total weight of the fuel. As I turn off each tank...because I have 4 fuel taps ,one for each tank the accumulated wight will change. So all you need to do initially is have either all tanks and sump empty or keep the sump full then calibrate this for the zero point then fill all the fuel tanks and have all taps open and mark that as the 100% mark. Then all the fuel on board will be calibrated. This wont change so you only ever need to do it on setup. Hopefully it will work :). I have now a couple of sensors and a I2C interface pcb so I will build a rig up at home and see how it goes. I have to write some software etc but can do initial testing pretty easily at home before it gets to the aircraft. I have 4 empty tanks from Mabel I am not ready to use yet so it should be easy

 

 

Some project updates

 

Rotax ignition modes are going well, No failures (well it wasnt a failure it wouldnt idle at low revs) only had one that didnt like the wire size but have upgraded that since then and no issues

 

Rotax/any aircraft ignition monitor

 

The basics works well just trying to find a cheap easy way of manufacturing the pickups we use to clip over the spark plug leads but the hardware works a treat

 

Flap brackets

 

Hopefully next week a new batch will be at the laser cutters

 

Ignition module tester

 

new main shaft is required the first one was just not good enough in tolerance for the bearing in the rotax housing. Will also change the support bearing mounting. I havent got back to it yet. I have more steel for the shaft I just have to get to it

 

BalanceMaster

 

http://www.youtube.com/watch?v=iZ8GqUNUcbM:157

 

This was a rough and ready video I did during the testing of the one Danny got in. It is for a 2 stroke we since found out. Guy Small got the proper one in...it is 10mm bigger in diameter. I have made a spigot for it to line up on the bolly prop hub and we will make a far better video of this one with and without weights on my prop to test which is actually better. This past few weeks I havent had any time to scratch myself but should be able to get back into it all very shortly

 

 

 

 

 

[bobcharl]

Hi Mark,

 

Read with interest your fuel gauge project.

 

But please put me out of my misery. Given that pressure increases with depth would the reading obtained with, eg. the four tanks half full and all turned to on not be the same as with three tanks empty and turned off and one tank half full and turned on?

 

I cannot figure how extra the fuel in extra tanks would alter the pressure.

 

What have I got wrong in my little brain?

 

If it would work it would be great.

 

Cheers,

 

Bob

 

 

[Kyle Communications]

Welcome to the world of brain screwing. I have done lots of research on this subject and I can not find anything conclusive. There seems to be different trains of thought about it. I am going to try it and see actually what happens. My theory is that fuel has a weight regardless of surface area because it has a specific gravity but height as in "the head" could very well change this weight but I am not sure. The only way to know is to set something up and try it. Either way no matter how high the fuel is above the sensor or what sort of surface area so long as the sensor is below the fuel it should measure something. Now because you setup the sensor to read no fuel and then full fuel....no matter what the scale you then calibrate the span of what you have so as that fuel depletes or gets turned off by a switch the pressure on the sender should change and of course give you a reading based on your calibration.

 

We will see once I get the electronics finished and hooked up to a computer so I can see the values. Then I can change the head height and also surface area but keeping the head height the same and see if it changes the calibrated values

 

Most of life is a experiment :)

 

 

[Rubidor]

Welcome to the world of brain screwing. I have done lots of research on this subject and I can not find anything conclusive. There seems to be different trains of thought about it. I am going to try it and see actually what happens. My theory is that fuel has a weight regardless of surface area because it has a specific gravity but height as in "the head" could very well change this weight but I am not sure. The only way to know is to set something up and try it. Either way no matter how high the fuel is above the sensor or what sort of surface area so long as the sensor is below the fuel it should measure something. Now because you setup the sensor to read no fuel and then full fuel....no matter what the scale you then calibrate the span of what you have so as that fuel depletes or gets turned off by a switch the pressure on the sender should change and of course give you a reading based on your calibration.We will see once I get the electronics finished and hooked up to a computer so I can see the values. Then I can change the head height and also surface area but keeping the head height the same and see if it changes the calibrated values

Most of life is a experiment :)

[Rubidor]

Sorry about the last post with nothing added, as these transducers measure pressure or head the “ head” value will change with every roll axis angle change, only going to be accurate or relevant as a straight and level setup with no g forces present also? Maybe, maybe not.

 

 

[Kyle Communications]

Hi Rubidor

 

They are straight pressure sensors so will just be measuring pressure. I have tried researching and still have no definate answer. I will know when I do it statically on the test bench and then when I fly. There is so much different info out there but it all seems to contradict itself. The only way to be sure is do it and measure it and see what I come up with. The best case scenario would be reasonably accurate fuel amounts over the whole spread of the tanks. Fuel tanks are also not all parallel sides so this may also create a issue depending on whether its weight or head height etc... If it gives me at least a 100% down to 50 and 20% accurately then that will be fine. The tank shape may need some correction factor put into the software to allow for the different volumes not being linear. Its all up in the air until I get something running but it should be a good exercise

 

 

[rotax618]

Unfortunately the venting of the tank will also effect the measured pressure, my Sav has forward facing fuel cap vents, they increase the air pressure in the tank.

 

Years ago I built a capacitive fuel gauge for my Drifter using two sheets of copper clad circuit board screwed together with nylon screws and separated by thin nylon washers. I measured the capacity with a Dick Smith kit. It worked OK most of the time but because of the change of chemical content and moisture in the fuel the gauge had to be set for the amount of fuel before each flight.

 

 

[JG3]

I don't know what all the fuss is about on this. I've used the outer tanks for years on many long trips, and never found the need for level gauges or sight tubes. Fuel burn is pretty consistent so time will indicate consumption. Always use the outer tanks first of course. Start a timer and from experience expect the fuel light to come on about 3.5hrs depending on how hard pushing it, then switch tanks....

 

But good move to replace that piddly little light with a flashing LED. Off the shelf from Jaycar and mounts easily in a 10mm rubber grommet. Really gets your attention.

 

 

[Blueadventures]

Hi Mark

 

I have a question about the brake disc safety securing to the main wheels.  I have seen two Savs recently that have not had the fastenings safety wired.  I cannot view a build manual.  Is it not required to have the fastenings lock wired.  I always do this to mine.  Cheers and good to see your recent live flying posts.

 

 

[Kyle Communications]

I will get the manual and have a look but I am sure it doesnt require it as they use nylocks on the bolts

 

 

[Kyle Communications]

Do you mean the way the disk is held onto the wheel?....those bolts have loctite on them that go into the raiser blocks

 

 

[Blueadventures]

Thanks Mark  These are the small bolts that hold the disc to the wheel rim. I see the rim has a hold but not the bolts used and no lock wire. Cheers

 

 

[Kyle Communications]

From memory they were allen key dome heads holding the disk to the rim. and they are loctited. I know I had to get mine off once and it was a mission to do it

 

 

[Blueadventures]

Thanks for the info. Just checking for my interest and to pass on any info. They were not sure as both recent purchases. Regards

 

 

[rankamateur]

Loctite needs heat to a bit over 300 degrees C to make the bond release. You can get it there with a heat gun if you don't have a butane torch.

 

 

[JerzyGeorge]

Good morning,

 

Disc bolts could be lock-wired or use medium strength locktite I used both and found locktite acceptable.

 

Keep in mind that you need to undo those bolts when you take a wheel off ( for a puncture or bearing repair)

 

Regards George

 

 

[Kyle Communications]

Most of you on here know I also make ignition modules for the Rotax. I have had a couple of itterations at making a proper test jig to test the units in a real world test when I make them and also for further development on ignition timing and also a new regulator. Danny and I went halves in a broken engine for all sorts of parts and I pulled the rear end off to get a generator and starting coils so I could make a jig that is exactly how the engine ignition and electrical system works. There has been a few trials and tribulations getting enough power to turn the shaft that emulates the crankshaft. The magnets in the generator are extremely strong and I needed a motor that I could get enough low down torque to tuen it. I tried several but they just couldnt cut the mustard so I bought a 1.1KW 3 phase motor and have a 2.2KW VFD to run and control the speed. The pulleys are just under 3:1 so I can only get to about 1680 rpm but thats all I really need to get it to. I have a electronic test box that tests the modules at 5000 rpm but needed to test the low end at where they start to fire.

 

One question answered was everyone has said that you need 400 rpm to start the engine. Not true you will see in the video the plugs start firing between 220 and 240 rpm. I still have the ignition module break out cables to make up and mount and also the generator wires have to come out to a set of terminals so we can work on the new regulator. Also I will setup a permanent timing light on it so we can check/ modify the circuitry for advance and retard mods we are thinking of. I have a new softstart module testing now that doesnt keep the engine running for 4.7 sec after it has started. it will stay retarded for only 1.5 sec just to show that it was retarded during the start phase

 

Here is a video I just took after I have most of it running tonight. A few more hours and it will have the rest finished off. But all in all I am very pleased with it so far

 

 

 

[Kyle Communications]

I have been having bad oil pressure fluctuations for a while and have been trying to solve it. Well looks like its fixed now with the help of a guy in the USA who has come up with a new oil pressure relief valve. For pics and explanation I have posted a thread in the engines forum..here is the link Bad fluctuating Oil pressure on a Rotax 912ULS

 

 

[eightyknots]

I don't know what all the fuss is about on this. I've used the outer tanks for years on many long trips, and never found the need for level gauges or sight tubes. Fuel burn is pretty consistent so time will indicate consumption. Always use the outer tanks first of course. Start a timer and from experience expect the fuel light to come on about 3.5hrs depending on how hard pushing it, then switch tanks....

But good move to replace that piddly little light with a flashing LED. Off the shelf from Jaycar and mounts easily in a 10mm rubber grommet. Really gets your attention.

I suppose the biggest issue with this is the reliance on one switch to 'tell' you that you only have a few litres of fuel left in the reserve tank. There have been a number of reports on the internet saying that this switch is not very reliable. The only way to properly test it would be to drain all 4 tanks and a little bit of the reserve tank as well to see whether the switch is operational.

 

PS: I cannot find any of the references on the internet now which speak about the problems with the reserve tank switch. Perhaps others may have come across this as well?

 

 

[IBob]

Hank,

 

if you use the standard ICP 4 tank setup, whereby the centre tanks are always on and the outer tanks are individually valved, you cannot do what JG3 is suggesting, which is burn off the outer tank/s first.

 

If you go to the arrangement Mark Kyle is using (for instance) which is a valve for each tank, you can then burn fuel from the outer tanks first. You can also check the lo fuel switch, if you wish,  by valving off all tanks while running on the ground. In addition, there is a button on the dash for testing the indicator lamp during preflight. I don't know what indicator they give you, but I will definitely be going to an LED there.

 

As for the switch, it is a reed switch, operated by a magnet attached to a floating collar which moves up and down a central rod. You can see the outline and the action if you hold your tank up to a bright light.

 

For myself, provided I am confident in the wiring, and have an LED indicator, I will be very confident in the reliability of this arrangement.

 

Also, on those occasions when I might use the outer tanks, (only for away trips in NZ) I would be setting a timer as JG3 does, and I would be very aware as cutover time approached.

 

Some of the earlier Savannahs were plumbed differently, having no vent pipe from the reserve tank. If these get air in the top of the tank, it sits there as a bubble, and can give false 'low tank' indications, particularly at higher altitudes, as the air bubble expands with falling pressure. These may be the problems you are referring to.

 

Your Savannah will be plumbed with a breather back to a wing tank, which eliminates this problem.