My Savannah S model rebuild Blog

[Kyle Communications]

The corrogated tubing is very similar to what ICP suppies for their kits now the last couple of years. The difference is the ICP stuff is really thin. This stuff is locally made down at the gold coast and is substantially thicker in wall. I would say at least double the thickness. I dont expect the flow to be any different to be honest. My fuel lines will be the teflon coated rubber injection fuel hose. ICP also use that thin corrgated stuff for the fuel but I am not using it for the fuel

The corrogated stuff I have only used for the water and oil.

I had a pulsing issuse in the oil pressure which drove me nuts on the girlfiriend. I posted a lot about it on the original savannah build thread. I ended up getting a adjustable oil pressure releif valve and that worked well but a LAME in WA that I know well had the same issue in a Sav and he found it was the curves in the hose from the oil cooler pipes becomming thinner in those bends and causing a restriction so he put a set of the internal springs into those 2 oil pipes to keep the hose the right diameter and that fixed the proplem. So I got the 2 output fittings at a about a 30deg angle coming off the oil cooler to make the bend better and of course the corrogated line doesnt squeeze small at all so this should hopefully stop that issue from happening again

[Kyle Communications]

Parts came in yesterday for the remote oil pressure sender mount. After 2 failures of senders previously on The Girlfriend I did a remote mounted one on that engine and no more problems after that. even with a VDO style mechanical one which are notorious for failing on the Rotax

[Blueadventures]

2 hours ago, Kyle Communications said:

Parts came in yesterday for the remote oil pressure sender mount. After 2 failures of senders previously on The Girlfriend I did a remote mounted one on that engine and no more problems after that. even with a VDO style mechanical one which are notorious for failing on the Rotax

Do you have a small orifice at the outlet connection of the engine and what size did you drill?  Looks great.

[Mike Gearon]

10 hours ago, Kyle Communications said:

even with a VDO style mechanical one which are notorious for failing

This solves a puzzle I’d not understood. Had a potential buyer for the rotax powered motor glider in USA. He cancelled and amongst 10 items was “analog oil pressure gauge dangerous”

 

I thought he might have meant connections were a problem. He was a very fussy NASA rocket scientist so I didn’t ask further.

[Kyle Communications]

On 20/10/2022 at 9:15 PM, Blueadventures said:

Do you have a small orifice at the outlet connection of the engine and what size did you drill?  Looks great.

Hi Mike

 

There is a adaptor that fits into the block for the oil its a 10x1 thread on my engine. It then gives you the sealed type of AN fuel fitting for the raceteck stuff. Its basically just AN style liquid fittings and a teflon braided hose. I got a set for mabels engine and also got exactly the same for the RANS engine

 

Mike Gearon

 

The older analogue senders have a wire wound resistor with a arm that runs across the wire to get the resistance...nothing wrong with them provided they are not pounded by vibration like in the rotax. The arm wears through the fine resistance wire in the sender and it fails because the arm sits almost in the same spot all the time when the pressure is applied by the oil. Dont worry the electron 4-20mA senders fail too just they are 8 times more expensive than the old VDO style ones. Rotax I think is on their 3rd type now due to the failures of the Honeywell sender..thing they have a German one now but they are 400 bucks or so each

 

[RFguy]

suggest this sender- compatible with most EFIS , for fuel and oil). 100psi for Oil, 15 psi for fuel pressure. (Thanks MarkDun)

 

https://www.ebay.com.au/itm/175192533261?mkcid=16&mkevt=1&mkrid=705-154756-20017-0&ssspo=_ZjsKGYLT-6&sssrc=2047675&ssuid=yHPQZk7zRBi&widget_ver=artemis&media=COPY

 

many sites with the same things, some have full model stock, some not.

Edited October 22, 2022 by RFguy

[Blueadventures]

14 minutes ago, Kyle Communications said:

Hi Mike

 

There is a adaptor that fits into the block for the oil its a 10x1 thread on my engine. It then gives you the sealed type of AN fuel fitting for the raceteck stuff. Its basically just AN style liquid fittings and a teflon braided hose. I got a set for mabels engine and also got exactly the same for the RANS engine

 

Mike Gearon

 

The older analogue senders have a wire wound resistor with a arm that runs across the wire to get the resistance...nothing wrong with them provided they are not pounded by vibration like in the rotax. The arm wears through the fine resistance wire in the sender and it fails because the arm sits almost in the same spot all the time when the pressure is applied by the oil. Dont worry the electron 4-20mA senders fail too just they are 8 times more expensive than the old VDO style ones. Rotax I think is on their 3rd type now due to the failures of the Honeywell sender..thing they have a German one now but they are 400 bucks or so each

 

Thanks Mark understand.  Just I hear that people put a restrictor in the adaptor that is drilled say 0.5mm so that in the event of a hose failure the oil escapes at a slow rate.  The hole allows the oil pressure through so the sensor picks it up. Best regards Mike.

[Thruster88]

The 0.5 orifice also prevents the oil pressure spikes hammering the sensor 

[Kyle Communications]

The older VDO die because of the block vibrations not the oil hammering. First I have heard of the restrictor for the pressure gauge though. The remote mount I did worked a treat

 

 

[Blueadventures]

7 minutes ago, Kyle Communications said:

The older VDO die because of the block vibrations not the oil hammering. First I have heard of the restrictor for the pressure gauge though. The remote mount I did worked a treat

 

 

The restrictor was a method I read about the remote mounting of the oil pressure sensor off the motor block.  I have in mind to do like you have but with a shorter flex hose so I can mount with a bracket onto the radiator as it is supported on four points that are the rubber mounts and therefore much reduced vibration and not far from where in currently is located.  I will do a method of a restrictor with it.  Noce to see your not that far off have assembly finished and then the fun at the airfield.  Cheers.

[RFguy]

The hammering with Jabirus killing VDO sensors is due to the PRV (not the pump) is know to be bad, and there have been several PRV mods by users .

here is the Jab oil pressure std PRV on a solid state sensor as required by Bob Panther. probably a bit off topic.

 

 

[Steve L]

Hi, I noticed in the picture the oil filter had a hose clamp with a lock wire attached. I recently heard Rotax didn’t recommend using hose clamps or similar around the filters due to cracking under the screw worm. I guess this is feasible. 
 

steve 

[Thruster88]

My friend with a 912 experienced a cracked filter due to a hose clamp. Fortunately the crack was only small. Spin on oil filters do not come off.

[RFguy]

they are bastards to remove at the best of times. It's why we all have oil filter wrenches...... suggest painting it half black, half white, easy to see if it has moved.

Doesnt hurt to put ur hand onto it with cowls off and check tightness. 

[facthunter]

A sloppy thread is your biggest risk or a seal misplaced . No tab will correct that. FEEL how it tightens up. Oil and Seat the seal and another 1/2 turn. Nev

[onetrack]

A narrow (20-25mm wide?) piece of insertion rubber under the hose clamp should fix any potential filter cracking problem? Might even produce a bit of vibration/noise attenuation.

[Steve L]

I apply torque seal on both surfaces (filter and base mount) being careful to line the marks up. Then apart from a visual check, leave the filter alone, no sense disturbing things. As most know, a filter tensioned by hand needs a tool to remove. 
 

I apologise Mark for hijacking the thread it wasn’t intentional,

 

steve 

[Kyle Communications]

Mabel is ALIVE !!!!!!...and no smoke...even better

[Marty_d]

Fantastic work Mark. Hey with your fuel splitter,  looks like you have 2 joined blocks. I thought only 1 x 5 point block was needed (fuel in, carb x 2, tank return, fuel pressure) - interested in why you have more?

[Kyle Communications]

Hi Marty..there is a method to my madness. There is a fuel pressure sender in one end then of course the 4 way fuel (one from the mechanical pump then 2 for the carbs and my fuel retun is on the other end of the block and a fuel pressure switch that is wired as per a previous post on here that will automatically turn on the electric fuel pump if I ever lose fuel pressure. There is a centre off switch so the pump is isolated..the top position of the switch is auto and the bottom is for manual on so it can all be bypassed and the fuel pump can be turned on at any time. I could have made a new fuel block but it was easier just to buy the manifolds and put them together....I need a little more weight up the front anyway as I have 20 thou skins on the rear fuselage sides and also 20 thou skins on the top of the wing and on the D section 

 

[Kyle Communications]

This is the circuit for the auto fuel pump backup. it very simple to setup and just needs to be in the fuel line downstream from the mechanical pump

 

 

[RFguy]

Mark, where do you buy those manifolds ?, PN ?

[Blueadventures]

On 13/01/2023 at 7:19 PM, Kyle Communications said:

Mabel is ALIVE !!!!!!...and no smoke...even better

Nice Mark; however I'm not a fan of teflon tape in fuel systems, use Loctite 577 or 567.  Looking forward to seeing first flight, must be close now.

[IBob]

1 hour ago, RFguy said:

Mark, where do you buy those manifolds ?, PN ?

RFGuy they're actually air manifolds for the likes of spray shops, come in a variety of sizes from China.
So available from outfits selling spray gear etc.
Or here are some from China:
https://www.aliexpress.com/w/wholesale-air-manifold.html?catId=0&initiative_id=SB_20230114151204&SearchText=air%2Bmanifold&spm=a2g0o.home.1000002.0&dida=y

[Kyle Communications]

Glen when I built the girfriend I got the fuel manifolds from Pirtek but since have found a place right near the airfield that sell all sorts of brass and plastic fittings. they have all of that plumbing and valves and stuff for irrigation etc. they used to be called Qld house of hose but have been bought out..cant remember their name but i think they are a australia wide company now. i will find out.

 

mike i have used the pink teflon tape a lot and it doesnt seem to deteriorate at all with fuel. I always make sure there is no tape in contact with any fuel path its just to build up the threads and do what it is suppsoed to do..... I have used it on car stuff as well. But only the pink stuff