My Savannah S model rebuild Blog

[Kyle Communications]

The top is the inlet side thats the pipe than cones down the back of the engine..the hotest water is coming from the pump but that is a little problematic I think to get the connection there although of course its the best place. Dunno will have a better look and think about it this weekend but it makes sense to do so. My RANS S-21 engine is a 2015 that we rebuilt and balanced I didnt think to look now I know its not the same since 2013. The engine is on a engine stand so will spin it over and have a look

 

[IBob]

Mark, the coolant goes from the pump into the underside of the heads, out of the upper heads to the 'spider' with filler cap etc on top of the engine, from there to the radiator LH, from there to the pump inlet. Fig 75-1 in the Heavy Maintenance Manual.
The coolant temp sensors are on the top of the heads, which is the hot coolant leaving the head/s.

[Blueadventures]

5 minutes ago, IBob said:

Mark, the coolant goes from the pump into the underside of the heads, out of the upper heads to the 'spider' with filler cap etc on top of the engine, from there to the radiator LH, from there to the pump inlet. Fig 75-1 in the Heavy Maintenance Manual.
The coolant temp sensors are on the top of the heads, which is the hot coolant leaving the head/s.

That will allow easy convenient installation of the part I described.  I didn't have time to confirm the flow direction.  Cheers

[Kyle Communications]

Thanks Bob..I hadnt actually looked into that and it makes sense..also will be much easier to install then..the pilot side allows much easier access

 

[eightyknots]

22 hours ago, Kyle Communications said:

Yes I am aware of the slight reduction of ID on the pipe. I have now though probably almost twice the cooling area of the radiator due to the new opening. Having a big bore kit fitted I am expecting more heat. The engine is the pre 2013 so the temp senders measure the head temps not the water temp. I am thinking about fitting some sort of water temperature sensor as well. The metal pipe will also help dissapate some heat as there is a lot of surface area of the pipe when you consider the corrogations on the pipe. Danny was over yesterday and we were talking about how we are going to mod the exhaust pipes. Hopefully next weekend I can get that done and if I get my backside into gear this week I will have the avionics ready to start the engine and have all the monitoring going. There isnt a huge length of the steel pipe on the pax side its only about 300 long and the pilot side is about 450 long. Now the radiator core is fully exposed and also the angle in the airstream is much flatter...it still is angled though so its a suck it and see thing I suppose. I am not expecting anything too dramatic

 

Mark,

 

If you could somehow paint the stainless steel pipes a matt black, you would get some additional cooling effect. Matt black radiates far more heat than silvery stainless steel.

 

However, you would also have to be careful that the matt black doesn't pick up more radiated heat from any high temperature heat source such as an exhaust pipe close by. 

[RFguy]

I don't wish to rain on everyone's party....but-

 

The amount of surface area on the pipes is I would regard as insignificant compared to the surface area of the radiator....

The radiator might have  an effective , forced airflow over about  2  square meters..... Yes- true !

 

And the pipe is just radiation, not forced airflow,  from a small surface area only  0.0003 square meters for 1meter of 22mmOD....

 

I believe it would amount to rounding errors compared to the radiator performance.

So the pipe surface area is likely to be 1/10000th of the radiator dissipation.....

 

 

 

[IBob]

One things for sure, Mark: with this degree of unsolicited  international assistance and oversight.......she's gonna be a verrrry cool plane........)

[Kyle Communications]

I just want to get her finished and flying 🙂

 

[RFguy]

typo in above should read 0.0693 m2

now compared to the 2 square meters fins and all at 30 m/s airflow  ,  the radiation performance from the 90deg C pipe assuming it was seeing room temperature (20deg C).
The 2 sqM- I might provide some math to how that was calculated.
400x 150 front area, 50mm deep core ,  say 9 fins per inch (2.82mm). 0.2mm thick each fin, call it 3mm pitch, 400/3 = 133 fins.

50mm deep x 150 high is 0.0075m2 per fin XC x 133 of them is 0.997m2. fins have two sides, so double that arae for surface area and we have  1.99 sqM

Now, there is space take up by tubing etc, but it's all usable surface area.

so, something like 2 sqM. at something like 10000W/sqM in that airflow. (total capability = ~ 20000W )

compare to the 0.07m2 at radiation cooling (albeit with a high Tdiff)  is about 300 W/m2 ! (total capability about 20W) IE 1000x difference. OK I exaggerated about 1/10000.

 

 

 

 

 

 

[facthunter]

Surely you are better to be "Roughly right"  than "precisely wrong'. In Aircraft design if you don't round off a few corners You'll have a boxy ugly slow aeroplane.  Nev

[Marty_d]

On 23/08/2022 at 11:10 AM, facthunter said:

Surely you are better to be "Roughly right"  than "precisely wrong'. In Aircraft design if you don't round off a few corners You'll have a boxy ugly slow aeroplane.  Nev

 

What, like mine?

[Kyle Communications]

Had lots of stuff going on in the personal life lately and havent had a lot of time for Mabel. This weekend I have finally managed to complete some important tasks.

A couple of weeks ago we got the exhaust system modified so its a nice fit with room for the water circuit and oil..also I dont have to remove the front left header pipe now to change the oil filter

During last week the hooks for the springs on the two modified exhaust headers were tigged on also made the stainless rings for the EGT sensors they are also tigged on as well and I have finally fitted the exhaust to its final position.

I decided I really like this corrogated stainless flexible hose. it is thicker than the ICP stuff they supply and I feel more comfortable with it. So the water circuit is fitted with it and now the oil circuit. The oil was a bit problematic trying to get hose that fits nicely over the 14.2mm outer diameter of the hose. It needed to be squeezed down to about 13mm to fit the good quaility oil hose I like to use and of course this stuff becomes the joiners. I used a collet chuck set from my CNC machine and used it to crimp down the tube to a size that I can get into the oil hose. It flattens the round ridges to get it to size but I did some tests and it does not affect its strength at all.

Got a nice water fitting from Danny's stash pile of stuff so I could get a water temperature sensor in it and that is now fitted. I soldered a silicone wire... the stuff I use for my CDI modules onto the base adaptor so I can just earth that to the engine block so it works properly. Have been wiring the dash and just need to get the headsets run through and fitted to behind the PAX were I will have my fuel switch as like before in the Girlfriend but its a different tank system so only have 2 switches not 4

Concentrating on getting all the wiring from the engine side to the firewall plug then I can wire through to the RDAC and will be almost ready to start the big bore engine

 

Finally got the production version parts in for the throttle mods and they are pretty nice. they tumbled all the parts so look really nice. Also my old tig is pretty stuffed now so lashed out and bought a new one...and ohhhh its nice...one of these automatic setup ones..works a treat. Now I have to spend a few hours in front of my hydraulic press to get all these to shape

 

 

 

 

 

[Bernie]

"my old tig is pretty stuffed now"

What's wrong with it??

Bernie. 

[Kyle Communications]

All the pots are no good..it only runs at full power you cant adjust it. Its about 14 years old now. I didnt have it for a long time my mate had it but he hadnt used it for about 2 years and when i got it back it had these issues. it is a good tig. But I dont have the time to go through it so just bought a new one. I will get to having a look at it when I get the time. But I have a lot of tig work to do on these throttle kits so needed to just make it happen

 

[RFguy]

Nice TIG work on those EGT sensors. 

[jackc]

Makes me kind of envious 🙂 I have all the gear, but NO idea!!

[RFguy]

Mark is not going to like me saying this....
I would suggest people  be careful about using the corrugated hose.  and NOT reduce any Inside diameters compared to the rotax suggestions.

The fluid math calcs say the corrugations are a bad idea. Sure, it looks pretty.  Yes I have done the fluid math - with some roughness assumptions.

All the rotax diameters used are 'just enough' in smooth pipe....

Now, given the corrugations are likely fairly smooth inside , there IS a degree of uncertainty to just how bad these corrugations are for flow.

They might not be as bad as I contend

If you want to use this corrugated hose, I would suggest measuring the pressure drop at the flow rates expected - 65 lpm for coolant  and 16 lpm for hot oil and cold oil.  It might be OK on larger diameters.

-glen

 

Edited October 12, 2022 by RFguy

[facthunter]

Viscosity is likely to have a big effect on flow rates with rough surfaces.   Nev

[RFguy]

For water..... viscosity =1

10 gal/min, for  1 foot, roughness ~ 0.05mm

1/2" ID : smooth = 1.4psi. corrugated hose : one type: 2psi, another type : 10 psi
3/4" ID : smooth = 0.2psi, corrugated : one type:   0.4psi , another type : 1.5psi

seems to vary between 1.5x to 4x depending on what it is....

https://hoseflex.com/wp-content/uploads/2015/06/PRESSURE-LOSS-PSI-per-foot-of-Hose.pdf

https://hoseflex.com/product/metallic-hose-annular/

https://specialtyhose.com/index_htm_files/Metal Hose Pressure Drop.pdf

 

[facthunter]

IF you reduce the velocity the drop will drop. Ie use a bigger section. Nev

[Kyle Communications]

Had lots of stuff going on in the personal life lately and havent had a lot of time for Mabel. This weekend I have finally managed to complete some important tasks.

A couple of weeks ago we got the exhaust system modified so its a nice fit with room for the water circuit and oil..also I dont have to remove the front left header pipe now to change the oil filter

During last week the hooks for the springs on the two modified exhaust headers were tigged on also made the stainless rings for the EGT sensors they are also tigged on as well and I have finally fitted the exhaust to its final position.

I decided I really like this corrogated stainless flexible hose. it is thicker than the ICP stuff they supply and I feel more comfortable with it. So the water circuit is fitted with it and now the oil circuit. The oil was a bit problematic trying to get hose that fits nicely over the 14.2mm outer diameter of the hose. It needed to be squeezed down to about 13mm to fit the good quaility oil hose I like to use and of course this stuff becomes the joiners. I used a collet chuck set from my CNC machine and used it to crimp down the tube to a size that I can get into the oil hose. It flattens the round ridges to get it to size but I did some tests and it does not affect its strength at all.

Got a nice water fitting from Danny's stash pile of stuff so I could get a water temperature sensor in it and that is now fitted. I soldered a silicone wire... the stuff I use for my CDI modules onto the base adaptor so I can just earth that to the engine block so it works properly. Have been wiring the dash and just need to get the headsets run through and fitted to behind the PAX were I will have my fuel switch as like before in the Girlfriend but its a different tank system so only have 2 switches not 4

Concentrating on getting all the wiring from the engine side to the firewall plug then I can wire through to the RDAC and will be almost ready to start the big bore engine

 

 

 

 

[Kyle Communications]

I have been struggling trying to decide where I mount my headset jacks. I asked around and there are a million different solutions that everyone seems to have. I have my fuel switches on the Pax side so I can reach them eaasily..The Girlfriend I had them behind the pilot and the pax respectively and it was a royal PIA. So I decided to fit them on the pax side so I can get to both sets easily. The aileron control rod cover made a nice mount and the jacks need to be isolated from earth so a plastic box mounted with rivnuts does the trick. made up the fuel taps and made a bracket from alu angle..this works much better than the one I made for the girlfiend..no drilling or tapping the manifold..just 2 screw clamps and its held in perfectly. The angle is rivnuted in place its all as solid as rock. While I as at the fitting place I grabbed another manifold and the fittings and this will be my fuel splitter from the pump to the carbs and the return to the tank but also where the plug is on the left the fuel pressure sender will go in there and the lot will sit on top of the engine.

 

Got all the fittings and pipe coming to allow the oil pressure sender to be remote mounted like on the girlfriend..that worked really well. 

 

Thought I had got a 22 way connector for all the sensor cables coming back into the aircraft from the engine bay to the RDAC but for the life of me I cant find it. It needs to be more than the std ICP one as I have 4 EGT this time and possibly a oxygen sensor.

 

So tahts my main holdup now is getting another connector..there must be a world wide shortage of bloody connectors..no one has stock it seems. I used a Deutsch one last time and it was a ripper but just not available now..the connectors are very expensive..like over $100. !!!!

 

 

[IBob]

hi Mark, I followed your lead on the fuel vales for SVA, have them mounted on the pax side where I can see them, works a treat. I made up some sort of bracket with scrap, and ended up attaching the manifold block with a couple of cable ties, it's absolutely solid.

As for the headphone jacks, that's a bit of a puzzle: mine were on the floor console, which is a terrible idea, I recently moved them to a box between the seats at about shoulder height, which is a lot better but still feels a bit clumsy......

[Mike Gearon]

Now I’m building an aircraft and actually building the second S21  I have a lot more appreciation for your efforts. Life certainly gets in the way. I’m luckily on a nice calm patch after years of turbulence. Hope yours improves.
 

Your S21 will I think be an easy build compared to what you’ve been doing so far.  I’m on the 2nd S21 with tail done. Horizontal, vertical stab and control surfaces. The elevator and trim tab an anticipated pain. Finishing up trim tab hinges today and I’ll make a YouTube video of what is likely a much better solution to fitting and drilling those hinges than the methods I’ve seen in various YouTube’s.
 

With regard to the stainless corrugated tube. Have you flow tested it? Just a simple hook up to tap and run it at different pressures on timed release. Maybe a meter of it in typical bends to really push the testing. Say 10 seconds for 2 litres at a certain pressure then compare to standard rubber hose. Then change the pressures up and repeat.

Edited October 15, 2022 by Mike Gearon

[Blueadventures]

41 minutes ago, Mike Gearon said:

Now I’m building an aircraft and actually building the second S21  I have a lot more appreciation for your efforts. Life certainly gets in the way. I’m luckily on a nice calm patch after years of turbulence. Hope yours improves.
 

Your S21 will I think be an easy build compared to what you’ve been doing so far.  I’m on the 2nd S21 with tail done. Horizontal, vertical stab and control surfaces. The elevator and trim tab an anticipated pain. Finishing up trim tab hinges today and I’ll make a YouTube video of what is likely a much better solution to fitting and drilling those hinges than the methods I’ve seen in various YouTube’s.
 

With regard to the stainless corrugated tube. Have you flow tested it? Just a simple hook up to tap and run it at different pressures on timed release. Maybe a meter of it in typical bends to really push the testing. Say 10 seconds for 2 litres at a certain pressure then compare to standard rubber hose. Then change the pressures up and repeat.

A good test would be time and measure unleaded fuel flow using a facet fuel pump via a length of the corrugated and some normal hose.  The lengths to be same as in aircraft between the delivery valves and the engine and also include similar bends and their radius etc.  That way you will know for sure the performance.  Or just do the fuel gravity flow test.  Ibob would have these from his build and Mark and others would have same from their builds pre flight test.  I have mine form Nynja but a different build so best to compare Savannah installations with the different fuel system materials.

Edited October 15, 2022 by Blueadventures