My Savannah S model rebuild Blog

[Kyle Communications]

Phil

 

I think you will find the dirt was scooped in when the wingtip hit the ground and opened up the sheet at the bottom

 

I got the front Dskin off tonight to be able to see the spar damage. It doesnt look too bad actually and I am sure I can repair it and it will be stronger than original. Its right at the end of the spar anyway and on the bottom. It is where you add on the tip section of the wing which really is just a thin sheet to extend the wing. it is nothing like the spar itself. You can see in the photos where the tip section is added on. I will need the last 2 front and rear ribs. I could rescue the outer rear rib but will just replace it. The rest of the spar looks good no twists or creases or cracks that I can see but once the other skin comes off I will clean it all down and have a good look. I will get the other bottom skin off tomorrow night and remove the bent trailing edge spar and make a new section for it at work.

 

 

 

 

 

 

[Kyle Communications]

Yeah when your on a roll and that rivet tool makes it so fast...I kept going to get the other skins off. You can see the outer half of the rear small smar just needs a new one and the main spar damage certainly looks easily fixable

 

 

 

 

 

 

 

[FIL65]

Yeh Mark, make sense that that dirt was injested when the wing impacted. Couldn't believe that much dirt could find a way inside a wing under normal conditions.

 

At least you can see what damage there is now, with the skins off.

 

 

[eightyknots]

This is a very interesting thread!

 

Great work Mark

 

 

[Kyle Communications]

Got the outer wing section off this afternoon so I could expose the end of the spar. After some advice it looks like it will be reasonably easy to fix. The new outer spar section I will make longer where it joins the main spar for a larger overlap and possibly add a strengthener to the angle section

 

 

 

 

 

 

 

[Kyle Communications]

The easiest way to work on the spar was to remove it...took 5 mins so was easy. I will look at straightening it with some annealing but if that doesnt work out plan B is to replace the bottom angle completely. I will make 2 of the bottom spar angles at the same time as the other wing is pretty much identical damage. I have checked out the spar and it is straight and no twists or any damage or stress to the strut mounts but will get others more knowledgable than me to look it over

 

 

 

 

 

 

[Kyle Communications]

We to my friends business on friday with Danny and we used his 12ft guillo to cut all the wing skins and the side skins. We can do all the small cuts left now on the gear I have access to. I removed the lower angle on the main spar as I have decided I will replace it. The bent bit of sheet at the end I can straighten out with some judicious work with nylon punches without stretching the alu. The outer panel I will extend to cover the hole at the end so that will give it extra strength anyway

 

 

 

 

 

 

[Kyle Communications]

Went over to Danny's place late today and got some solid rivet crimpers and 5/32 solid rivets to practice doing some on the old angle before I do my spar. Also picked up 2 bits of angle the same size as the original that he managed to source..this particular size is difficult to come by. I will make 2 spar bottoms using each as a drilling gauge. The second spar is from the wreck Danny got...someone removed the fuel tanks from the wing and sliced the bottom angle with a grinder so it is stuffed. Well only if you dont replace the bottom angle like I am doing with mine. I made a tool from plastic in the lathe to start bending back to reasonably flat the outer web section of the spar. I will make a larger tip extension to go onto the spar like the one next to my spar but the web will extend right over the last large hole and up to the vertical support in that last section. The plastic tool you work with a hammer on the bend ridges slowly and in small increments this allows the metal to bend back without stretching the aluminium. Its never going to be perfect but all the tension has been taken out of that part of the sheet. The new web extension will be riveted to it and the angles top and bottom as well so it should be much stronger than original.

 

 

 

 

 

[rotax618]

Great that you could get the same angle, will be an easy job from here and the spar will be dead straight and like new.

 

 

[Kyle Communications]

Danny managed to get probably the last 3 pieces in OZ some time ago...He doesnt need them for his so I am scoring 2 for my wings and I will probably use the third to replace on the spar in the picture for him so we will have at least 1 possibly 2 spar wing spars if ever needed or do another rebuild

 

 

[Kyle Communications]

Drilled the 3 bottom angles for 3 spars..2 left wings and one right wing. The third one was the spare spar we have so will have that fixed. It was hard work doing the angle for the spars....169 holes in each spar angle. Luckily they are used as drill guides the old ones you just have to get your head around left and right orientation. Picked up a sheet of 0.025 yesterday I need to make the wing trailing edge outer half section. Cut the end off the sheet to make the spar tip extensions from and then cut off the strips to make the trailing edges. Just so happened the folder was setup doing for brackets at work at 20mm so I used it to bend the trailing edges and also the spar tip extensions which I have made longer to go past the bit that I had to panel beat on the spar end this will have a much bigger overlap...remembering left and right for the tips. The trailing edge there is no left or right until I put holes in so that was easy. Pretty much now will be cleaning up the spar before I solid rivet the bottom angle on and also now have some good etch prime as well so lots of cleaning and spraying and riveting this weekend and I should have the spar finished and the wing well and truly getting back together. Once its done I will get the other wing and do it as I have all the parts needed made so it shouldnt take too long at all. Danny has the punch for the 100mm holes for the spar tip extensions so have to get that done as well

 

 

 

 

 

 

 

[Kyle Communications]

Was supposed to be starting cleaning bits and etch priming today but got side tracked trying to get the holes done in the spar extensions. Danny had a go at making some flanging tools but never got them finsihed so I grabbed the bits and tried to work out the best way to get them done. So spent the day on the lathe making and modifying bits but finally ended up with something that works pretty well. It needs a bit further refining but I only had to do the 4 holes in each extension so it will do. The result worked out pretty good..the first extension the flanges are not that symetrical on 2 of the 4 but it does the job and they wont be seen anyway, You get better at it the more you learn of course so here is the other extension pics. Also a pic of the tool I made. These holes are 100mm

 

 

 

 

 

 

[Head in the clouds]

This is a very interesting thread!Great work Mark

Yes, I couldn't agree more. I've really been enjoying watching this all come together. When I saw the first pics of the crashed airframe, to be honest I don't think I would have given thought to trying to repair it but it's looking pretty good already and I expect it won't be all that long before it's back in the air, probably better than it was originally.

 

Even so, I can see there's an awful lot of work, money and effort gone into the rebuild already, nothing to do with aircraft is easy or cheap.

 

It has to be the best thought-out and executed repair job I've seen, and so well documented as well. I imagine it will encourage a few more folks to have a go at a repair or restoration.

 

Nice work KC!

 

 

[Kyle Communications]

Thank you Alan for your very kind words.

 

Mabel will be stronger than original when finished a little heavier of course but I believe certainly much better than a current kit. I have been hankering for a long while to get back to making another aircraft and cant afford yet the one I want to do next so this filled the gap really well. My XL is already been spoken for and going to go to a good home when I finish Mabel so the plan is to keep Mabel when finished and fly her and then get the Rans S20 Raven kit and build it as a taildragger and I at this stage intend to keep both aircraft. I really do enjoy doing this, I think its just a throwback from all the model aircraft building I have been doing since I was 12 its just this is on steroids and metal, plus I can actually sit in it and fly it when finished :). The only part of this whole process I dont like but have to do of course is all the cleaning and prepping of the metal. That is what I am doing this morning is cleaning and prepping the spar to go back together.

 

My efforts on Mabel pale into insignificance when I read your Doomaw thread and look at your design,welding and machining skills. At least mine I have patterns and bits to copy/remake but yours is all from scratch ... a huge job

 

Mark

 

 

[eightyknots]

My efforts on Mabel pale into insignificance when I read your Doomaw thread and look at your design,welding and machining skills. At least mine I have patterns and bits to copy/remake but yours is all from scratch ... a huge job

Mark

I also think that! The DooMaw is a gigantic task. I take my hat off to you Alan.

 

I also take my hat off to you Mark: this rebuild is amazing and I love reading the updates when they come through. I hope your (tedious) cleaning and prepping will be all completed by the time you read this.

 

 

[Kyle Communications]

Hi all

 

Havent been doing a lot with Mabel lately as I have been having a massive clean up and throw out in the big shed that I am doing the rebuild in. I need to make space so I can start putting wings back together. I have to build a new table..which will only take a couple of hours so I can make sure they are nice and straight when done. I filled up the van 2 weekends ago and when I turned up to the dump the shiela at the front asked me if the load was commercial or domestic..I said love I am cleaning out my big shed at home...she says ok away you go. I looked over at the scales gauge and the van weighed 3.2 tonne !!!!! its gross is 3.5 tonne. So I have almost another load ready to go this weekend. Its not finished yet and is much clearer than in the picture attached here. I have spent 2 full lots of 3 days off doing this and it has been breaking my heart throwing a lot of this stuff out but if it hasnt been used in the 12 years I have been here then most likely it wont be for the next 12.

 

So not much work on her except I have been cleaning parts and alodining all the small bits. I have the rudder parts and wing ribs and all the small trailing edge parts alodined and a lot of the brackets and parts in the nose section alodined as well. getting the black stuff off is a pain at least I will escape some of it as the guys who built this had a aversion to using a lot of it which for me is a good thing.

 

I have started alodining the frames in the rear and I will make up a small tank out of wood and plastic sheet to do the longerons as well. The front mounts for the tailplane and the former it is attached on we will beef up and the strengthener runners on the former as well. as it holds the complete tail on the plane and it just seems to be only just big enough so we want to make it a little stronger. I am remaking all the wing mounting attachments as well. The main 1/4 inch spar attachment the wing strut brackets and the rear strut bracket and the rear wing bracket on the top rear of the cabin is being redone as well. They are not much work at all so we thought we would replace them just incase. They all look ok but they are the main attachment points and my Mabel and Danny's aircraft have both had big shunts to the wings so for very little time and money its better to be sure.

 

Put a new controller in my CNC machine as well although that really only took a hour or so but now I do not need ant PC to run the CNC at all it used a stand alone embedded controller. I just feed it with the Gcode from a USB stick and it works so much better. It has now far better motion control. Danny made a couple of formers for the wing ribs so we can make sure they are straight and the correct size all over but needed to have a couple of holes in them to fit the relieved edge holes in the ribs so I fired up the machine using the new controller and used the inbuilt wizard to program the sizes etc and it worked a treat. So we have the forming templates now for ribs so they could be used to make new ribs if necessary but they are only being used here in straightening up everything

 

 

 

 

 

 

 

 

 

[M61A1]

Hey Mark, I would probably give those bits just a little bit less time in the Alodine bath, they look almost over cooked. A light golden tinge is about ideal.

 

 

[Kyle Communications]

The first lot I did I used it as they said but I have since diluted it. It is premade solution and in that state it is used for brushing on. Since diluting it the colour is lighter and the time in the bath is easier to manage.The frame ones are the latest I have done and they are lighter in colour than the first lot . Thanks for the heads up Mick

 

 

[FIL65]

Hi Mark,

 

Have you thought about brush alodining the rest of the rear section of the fuselage.

 

 

[Kyle Communications]

Hi Phil

 

The problem is you have to acid wash it first anyway before you alodine it to prepare the surface so you just cant paint it on. Its easier for me at the moment to pull it apart as its all clecoed at the moment and do the frames in the plastic tubs I have now. The longer parts I will just make up the baths long enough to take the rest as required. It will only take 15 mins to make each bath up. I dont think I posted a picture of how I have done all the parts so far. next time I will take some pics. This weekend I hope to put the wing assembly table together and I will continue on and finish the fuselage internal frames then make up the long baths for the longer items

 

 

[bexrbetter]

Are you using 0.20" for everything now including the longerons?

 

The part's colour looks great! - is there an actual issue with them being "in" too long?

 

 

[FIL65]

Sorry Mark, didn't look close enough at the photos,to see you had only clecoed the rear together.

 

 

[Paul davenport]

Good to see you are still at it. It's looking like it's finally assembly time ?

 

 

[Kyle Communications]

Hi Bex

 

The longerons as std are 0.020 and I have kept that the same. All the 8 skin panels on the rear section of the S are 0.016. I am changing the 2 flat side skins which are the largest to 0.020 and keeping the rest at 0.016. All the wing skins are 0.016 but I am changing the top wing skin and the front D wing skin to 0.020 and leaving the underneath skin at 0.016. We are going to preshape the front D skin before it goes onto the wing as well.

 

The other beefing up we are doing is the front tailplane mount bracket in the rear the attachment plates are quite thin and we both think they need beefing up a little and also the 2 former strengtheners on that former so will make new ones of those a picture or two will show what I mean. We are also making some slightly thicker firewall strength brackets and also tieing in the front bottom of the firewall where it attaches to the bottom front skin back to the rudder pedal mounts. Its easier to show a picture when its done to explain it as that whole front section of the savannah is very lightly built and really needs a beefing up and that can be done easily without adding too much weight.

 

The wing skins and the side skins will add about 5kg total in weight and the other parts will add maybe 2 or 3kg but the extra strength the aircraft will have then will be much greater because as we know even though we can fly them here at 600kg they really are only built for 450kg. Both Danny and I have enough experience with seeing enough bent and broken Sav's to know where the really weak points are so both of our S models will be beefed up a little. I am just about to make all the wing spar and wing attachment brackets from new 1/8 sheet as I just wouldnt trust the ones I have after the bangs on each wing mine has had and also Danny's as his was picked up by a willie willie and dumped on its back and had some wing damage as well.

 

I am actually doing a fair bit more than I planned to on mine as I was not happy with the way it was originally built, so the whole front will come apart now as well and I will remake some of it and fix what I consider to be easily fixable as well. I am doing all this replacing of parts and alodining to get rid of the corrosion I found. There is a bit of corrosion in mine because there was not enough black stuff put on the aircraft when it was built and Danny's was built by the same guys and his is the same. Just not enough care and attention was paid to it when they were built to be a long lasting airframe...well in my opinion that is and its my bum in the seat!! so it will be perfect when it is finished

 

I am not sure if overcooking the alodine is detrimental at all but the first parts I did are much darker than the rest but they all look ok. Mick should be able to answer that question but most of the last half of the parts I have done are certainly not as "cooked" as the first. I dont think it does any damage at all as the acid wash seems to open the pores of the metal and the alodine seems to fill it all in and seal off the oxygen to it so it cant easily corrode

 

Mark

 

 

[M61A1]

As long as it doesn't get a powdery looking finish it should be ok. If it's overdone long enough to be powdery, other surface finishes may not adhere well.

 

From the Henkel TDS

 

6. Surface Preparation: Cleaning: All metal to be treated with the processing solution must be free from grease, oil and other foreign material before treatment. A complete line of cleaners is available. Our representative will recommend the proper cleaner for your processing needs. Water Rinsing: After cleaning, the metal must be thoroughly rinsed with water. The rinse should be overflowed continuously at a rate which will keep it clean and free from scum and contamination.

 

7. Treating with the ALODINE 1200S-RTU Processing Solution: Each alloy reacts with the ALODINE 1200S-RTU conversion chemical bath to produce a coating that is characteristic of that alloy. For the treating time selected, the bath should produce a light iridescent gold to tan coating on aluminum. The data contained herein are normal for most installations; however, your technical representative may suggest a deviation from this data if indicated by production conditions. If the ALODINE coating is powdery, the cause may be one or more of the following:

 

1. The work has been improperly cleaned and/or rinsed.

 

2. The coating time is too long. 3. The bath temperature is too high.

 

If the ALODINE coating is too light, the cause may be one or more of the following:

 

1. The treating time is too short.

 

2. The temperature of the bath is below the specified range. Operation: Time: 15 to 30 seconds. Temperature: 70° to 100° Fahrenheit.

 

8. After Treatment: Rinsing and Drying: Unreacted coating chemical should be removed by one of the following methods: 1. Flush the work thoroughly with clean water followed by (a) air drying; (b) blowing dry with compressed air; © warm or hot air drying; or (d) wiping dry with clean cloths. 2. Wipe with water-damp cloths followed by wiping dry with clean cloths. Any seams, joints and crevices should be blown dry with clean, dry, compressed air and the moisture splatters wiped dry with clean rags.

 

The skins can be done by starting at one end and sliding them through the bath.