Another NEW Savannah XL on its way

[Tex]

AH I see.... just to throw another spanner in the works... a plastic tank

 

 

[Gundy]

I've built 3 Savs now and helped on 3 others. We all used good ol Stag not one problem. One of those planes is five years old with over 600 hours on it. Only thing I've ever been told is wrong with Stag is "it's hard to get the fittings apart once the Stag is dried". I don't plan to pull the fittings apart in the future, if so I'll buy a new fitting. Gundy

 

 

[Kyle Communications]

Hi Gundy

 

The stuff I put on was Stag I thought. Dont know why but only 1 tank has leaked and the stuff started breaking away so maybe I got a bum tube or something. Anyway it will be fixed for good now so if I do have to remove the fittings it will be a drama. Will do it this week coming I should have more time then. Last week was really busy and didnt get a chace to do any flying other than last Sunday. Weather looks crappy again for this week so better to do the work when the big fella upstairs starts crying

 

 

[Blueadventures]

Hi BobI found the answer its called Pro-Seal its a epoxy used to make fuel tanks etc for aviation... I have got some and will redo all 4 tanks main outlets and the bottom fittings for my sight gauges. I also got some fibre washers which will go on the outside over the fittings between the tank wall and the nut. I will put the proseal on the tank outer wall then the fibre washer then more proseal then tighten the nut up then make a fillet around the nut and tank so its a permanant seal...it wont leak anymore. The other tanks at this stage have not leaked but I have no idea why the nut went up another 3/4 of a thread. Maybe the plastic tanks depress over time not sure but it will be fixed next week. I am up the farm this weekend so have a big day slashing and mowing and whipper snipping and if I get some more time I will finish the welding on my internal lift in the shed...bloody cold and widy up here tonight too so will be brass monkeys here in the morning me thinks

 

Mark

Hi Mark

What do the Savannah people recommend for the sealing?

 

Cheers

 

 

[Kyle Communications]

There was nothing in the manual about sealing the fittings at all. I put sealer on them just to make sure but obviously mine turned tits up...so this time I will make sure with the pro-seal...I will take some pics when I do it and post them. Luckily I can get to my tanks easily

 

 

[Kyle Communications]

Hi All

 

Well what a job redoing my tank fittings has been. After much asking of many knowledgeable people I have come up with definitely to use PR1440 or also known as pro-seal for the sealing although none could tell me if it will adhere to the plastic tanks. I spent friday getting my tank flaps tied back out of the way so I could get at the fittings to take them out. I removed the fittings today and cleaned the tanks out as best as I could on the inside although I will take my air compressor up there tomorrow to blow them out to make sure there are no small bits of left over sealer inside. I have also used a draw wire to get the fittings out and attached another draw wire so I have a catenery to slide the fittings back through so they go through the holes when I put them back in with the epoxy on them for the inside. the outside will have more glue applied to fill any space then a fibre washer then more glue then the nut then I will wipe the glue around the outside as well. The theory is the glue should compress in the space between the internal head of the fitting and the fibre washer this should seal off everything and as a backup the glue on the outside should seal it all off.

 

When I was removing the old sealer some was hard as nails and other ones were starting to get soft so fuel must have been starting to come through so probably timely I am doing all of the ones that are immersed in the fuel. I will take some more pics tomorrow after they are finished. I am making a small tool up to get any sealer left over on the inside of the hole you can see it in one of the photos.

 

 

 

 

 

 

 

 

 

 

[Kyle Communications]

On another note Steve Donald has been talking about making a underbelly pod for his Sav for the long trips he is heading out to Birdsville later this year in the Sav with the better half. Steve doesn't have any weight issues like me and my Mrs and trying to stay within limits. He called in today and showed me the pod wow doesn't it look flash and very functional. Here are some pics I took today after he trial fitted it. It still needs riveting and painting and latches etc but all weight will be under the CG and there is enough room to put 2 empty 20litre jerry cans and of course lots of other stuff in there.

 

He found a source of reasonably priced strobe led lights its 4 of 1 watt less in lenses and I have seen it operate reasonably close and they are really bright but he will be flying tomorrow so while I am up there I will get some video or pictures to see what they are like at distance. He has mounted onto the front nose leg with a easily fabricated bracket so is easy to fit and also the strobe/flash patter is changeable as well

 

 

 

 

 

 

 

 

 

 

[eightyknots]

I understand ICP makes bellypods for the Savs but this one looks very functional.

 

However, I DO wonder how many knots are lost with one of these fitted? Also I think that the LED strobe lights fitted like this will cause quite a bit of turbulence around the front undercarriage because of the space between the two. A 1, 2 or 3 knots may also be lost because of this.

 

 

[Kyle Communications]

There is no speed loss at all with the strobe so Steve tells me he does expect 2 knots or so with the pod but he isn't concerned as it really isn't much let's face it it's only 2 nm every hour of flying

 

 

[eightyknots]

There is no speed loss at all with the strobe so Steve tells me he does expect 2 knots or so with the pod but he isn't concerned as it really isn't much let's face it it's only 2 nm every hour of flying

I expect there would be some loss of speed/increase of fuel with the "flat plate" shape of the strobe lights. I always wonder why there is not a small trailing edge fairing around the front undercarriage strut to improve the airflow? (see diagram)

 

 

 

[Kyle Communications]

Its pretty small so I wouldn't think you would see much detriment anyway. After I see Steve's tomorrow I expect I will order 1 and fit it as well. I am still working on my anti collision light for the top of the fin it has 4 of 10watt red leds and I will use 2 white 10watt leds on each wing tip for the strobes on the tips. I am trying to find some clear covers so I can make them up. I have made up my anti collision light from aluminium I have turned up on the lathe and some polycarb tube....its unbelievably bright you can not look at it even in bright sunlight and 20 mtrs away. There is a Oring seal in the base which hasn't been put in yet but the groove is there just need to sandblast the inside of the tube to make it diffuse the light and polish up the aluminium also need a few more lightening holes in the base

 

 

 

 

 

[av8vfr]

Hi Kyle,

 

For clear covers try a hobby store for a scale P51 canopy or the like. Aerodynamic and light. Matt

 

 

[Kyle Communications]

I probably have a few canopies here never thought of that actually......although some are quite thin but I have a mate who makes canopies with a vacuum press so could get a thicker one made.....thanks for the headsup...think outside of the box

 

 

[Graham Pukallus]

Mark, here are some photos taken today at the Bowen Areo Model Club of the model plastic canopies that we spoke about re cowl repair, a cheap and easy solution to streamline potrusions etc. Graham

 

 

 

 

 

[Kyle Communications]

I will speak to Dave a guy in my model aero club this week about his canopy machine. All I need to do is make the base shape of the wingtip light area the Sav has and do a plaster model of it and he can pull a canopy from it that way I can machine out the base to the right shape it will have a lip on the base to screw the canopy to then I can put the 2 leds at a nice angle to each other to get the spread. I took some video of Steve's leds on the nose leg today I will do a short video up and post to youtube. They really only view from straight on any more than 10 to 15 degrees to the side you can't see them but he was on final for 24 today and not directly on me but I could actually see it flashing so it would have been really bright from front on....he was probably 2 nm away from me when I saw him.

 

I did 2 of my tanks on the pax side today I didn't do anymore as I want to make sure this PR1440 goes off ok. I did a test run with some PR1750 last night as the tubes it comes in is a bit funky. You need to mix it in the big tube internally and the hardener is squeezed in via the plunger I didn't do it right I am sure and the epoxy hadn't really gone off properly this morning but I didn't mix it correctly so I worked out the right way after that and did the 1440 the correct way. It has a pot life of 30 mins and a tack off time of 4 hours so I thought I better just do 1 side first that way if it stuffs up I only have to pull out 2 tanks instead of 4 tanks. It at this stage looks like it doesn't set hard I will confirm this tomorrow but the left overs I have in a cup here seems to have gone off and is very rubbery but not hard I think this is the way it is supposed to be. Some pics attached of what the mixing tube looks like and the second plunger for the hardener but its very messy to work with

 

 

 

 

 

 

[Kyle Communications]

Here is a short video of the strobe light on Steve's Sav. It is very directional and today was very bright sunlight

 

 

 

[Hadyn Bell]

Hi Mark,

 

Could you please advise what the "black goop" is as we are running out and require more of it or a suitable replacement.

 

Cheers

 

Hadyn

 

 

[Kyle Communications]

Hi Hadyn

 

Yes getting the black coup here is impossible I think I tried chasing it down and couldn't find it. I ended up ordering another can from Tom and have about 2/3 left if you want it. maybe Tom has some extra in stock I am not sure or maybe Reg has a stock of it but I couldn't find anyone here who knew of it at all as its water based

 

Mark

 

 

[bobcharl]

Haydn,

 

I ran out also, but got more from Reg quite promptly.

 

Bob

 

 

[Hadyn Bell]

Haydn,I ran out also, but got more from Reg quite promptly.

Bob

If I order it now I should get in about 7 days unless it has a D.G cert, then it will come by sea freight and I might see it in about 6 weeks!! O no, does this mean we wont be building this weekend, what will one do....The joys of being stuck out in the Pacific ocean! Might end up using a tad of that wattle super etc spray can.

 

Tom pointed out that before we start the cabin build forward, while we have working room, it is a good idea to cut and fit up the baggage compartment trim and as we have the rear fuselage section all skinned off this is what we might do...

 

 

[Kyle Communications]

Well spent a fair wack of the day today cleaning out the tanks with a rod with tape reversed so it has the sticky stuff on the outside to pick up any small pieces of crap left inside the tanks. Then I filled each tank in turn and flushing them 3 times each and still got more crap out but all 4 tanks are now very clean...well they seem to be. I have filled all 4 tanks now with 10 litres in each outboard tank and 20 litres in each inboard tank I will leave it overnight and check to see how they are in the morning. I expect them to be all fine now and the biggest test will be when I open the cabin door in the morning and see if I can smell any fuel. The Pro-seal/PR1440 is messy to work with but when it sets it even looks like the fuel will not penetrate anything. To make sure all tanks are clean still I will drain each in its turn into the sump which remains empty at this stage and see if any stuff comes out in the fuel after this I am sure it all be perfectly clean and ready to use. I will put the fuel back into the tanks and be ready for a fly when the weather gets better....25 to 30knots today and supposed be be like it most of the week.

 

Got my prop pitch gauge finished and checked the prop again and found 1 blade just slightly out so will fix that tomorrow so it will be ready for balancing later next week...hopefully the only other thing to do is to try to strap the main water hose up a bit more so that the radiator stops rubbing on the cowl its sort of fixed but if the motor moves a bit it still rubs it would be nice to get about 6 or 10mm clearance from the cowl I am sure the carby is now ok as well. I will try to take some pics tomorrow of it all and post them

 

Mark

 

 

[Kyle Communications]

On another note about my lights and making the covers. One of my model aero club mates was here and I was talking to him about it they do it differently nowadays. You make a mold of what you want the shape that is then cut the bottom out of a plastic soft drink bottle you then put the mold inside and hold it against the inside edge of the bottle with packing then heat the bottle with a heat gun and it apparently shrinks down and beautifully around the mold when it cools you cut it off and voila you have a cover and just use the mold to make another. A couple of pics attached to show the one he did .....he bought it around for me to look at. It hasn't got as much compound curve like I need but he tells me it will still work the same. If it works it will make life very easy I may even redo my tail anti collison light housing to make it more streamlined

 

 

 

 

 

 

[Blueadventures]

On another note about my lights and making the covers. One of my model aero club mates was here and I was talking to him about it they do it differently nowadays. You make a mold of what you want the shape that is then cut the bottom out of a plastic soft drink bottle you then put the mold inside and hold it against the inside edge of the bottle with packing then heat the bottle with a heat gun and it apparently shrinks down and beautifully around the mold when it cools you cut it off and voila you have a cover and just use the mold to make another. A couple of pics attached to show the one he did .....he bought it around for me to look at. It hasn't got as much compound curve like I need but he tells me it will still work the same. If it works it will make life very easy I may even redo my tail anti collison light housing to make it more streamlined

Hi Mark

 

You could consider setting the lights in clear casting resin. Its UV rated and $25 per liter /kg. The lights are then waterproof and also vibration proof. I make them for boats to protect against water ingress damage, these are LED and need to be protected from over voltage as heat is a killier to LEDs. All you need is the mould shape, looks like the model canopies are the shape and size, give the mould a coat of mould release wax and polish them. Then apply first coat to the mould so your lights dont protrude through the surface and when is sets off (not gels off) about 40 mins later place the light fitting in and pour in the required resin. Your mate with the strobe on the undercarriage leg could do the same and make a perfect fit light setup and in aerodynamic shape. Also Jay car sell Xenon Flask tubes and strabe triggers so what light / strobe you need can be crafted to order. And not too expensive. Any questions just ask.

 

Cheers

 

Mike

 

 

[Kyle Communications]

Hi Mike

 

Thanks for the other options I hadn't thought of solid casting the led into it then I wouldn't have to make a aerofoil aluminium base up either. I could just drill through at the front and back for the bolt attachments. Where do you get the clear casting resin?. I use CG composites for all my model mold making and also their resins for making the aircraft. I know how to do all the release agent etc as I have made these for 30 years. My aluminium base for the leds will be quite light then I just need the front and rear angle plates on a small rectangular base to mount the high power leds onto. The 10 watt leds are around 8 volts each so the wing tips will only need 16volts or so but need up to 1.7 amps but I will run them probably around 1.2 amps there doesn't seem much difference in lumens with the lower current. I am using a led driver pcb with constant current adjustment it works really well for the anti collision led as there are 4 of them so needs around 32 volts the up converter work well and seem to handle the switching nicely. I will run all the leds from a small micro to do the flash patterns for the 2 different sets. I am not a big lover of the xenon tubes as they create a lot of noise than can filter itself into the DC on the wiring and give some noise issues especially on the radios and also maybe the EFIS I have now the led technology is so much better and truth be told probably more powerful now anyway.

 

Whats the name of the clear resin and where can I get it please

 

Mark

 

 

[Blueadventures]

Hi MikeThanks for the other options I hadn't thought of solid casting the led into it then I wouldn't have to make a aerofoil aluminium base up either. I could just drill through at the front and back for the bolt attachments. Where do you get the clear casting resin?. I use CG composites for all my model mold making and also their resins for making the aircraft. I know how to do all the release agent etc as I have made these for 30 years. My aluminium base for the leds will be quite light then I just need the front and rear angle plates on a small rectangular base to mount the high power leds onto. The 10 watt leds are around 8 volts each so the wing tips will only need 16volts or so but need up to 1.7 amps but I will run them probably around 1.2 amps there doesn't seem much difference in lumens with the lower current. I am using a led driver pcb with constant current adjustment it works really well for the anti collision led as there are 4 of them so needs around 32 volts the up converter work well and seem to handle the switching nicely. I will run all the leds from a small micro to do the flash patterns for the 2 different sets. I am not a big lover of the xenon tubes as they create a lot of noise than can filter itself into the DC on the wiring and give some noise issues especially on the radios and also maybe the EFIS I have now the led technology is so much better and truth be told probably more powerful now anyway.

Whats the name of the clear resin and where can I get it please

 

Mark

Mark, its polyester casting resin with styrene and the catalyst is the usual MEKP. Its an fgi product so just try your local fibre glass resin surpliers. Make sure you gat a uv stable product.

Cheers

 

Mike