building my Savannah-S in germany

[MajorTom]

Finaly got all together to do / redo my solid riveting.

 

- bought the right rivets AN470 AD-3-3 and the right die

 

- found this nice pliers Knipex 86 03 300

 

- drilled a hole 4,75mm right throu it

 

- made a die for the shop head side

 

result is promissing, easy to operate with one hand, more than enough power for those small rivets....

 

finished rivet is straigt and nice, what a difference to my first 200 botchy attempts

 

 

 

 

 

 

 

 

[IBob]

Yes, this looks promising!

 

So:

 

1. Looking at the right rivet in your pic, it has not squeezed straight. This is because the tool has been tilted a little to the right when first gripping the rivet. So it has not squeezed exactly along the axis of the rivet.

 

This 'first grip' will be difficult to judge with your tool. Professional squeeze tools have the handles down in line with the axis of the rivet, which makes this easier to judge. I wonder if a 3rd handle could be fixed to your tool, in line with the axis of the rivet, making this easier to judge? This would be used to first align the tool, then the squeeze would be done with the 2 handles you have now.

 

2. The professional squeeze has adjustment for how much squeeze. You set this up, then every rivet is squeezed to the same length. Are you able to do this with the mechanism of your tool?

 

 

[IBob]

My routine for squeezing was:

 

1. Clear rivet hole gently with awl (because my skins were primed both sides, this cleared paint from the holes).

 

2. Place rivet and make sure it is fully 'home'.

 

3. Position tool on top of rivet only, but do not grip or squeeze: the tool is only touching the top of the rivet.

 

4. Align the tool to the axis of the rivet. (I used the edge of the bench to help with this, so the wing/flaperon etc was first carefully positioned along the bench edge. For me, this made aligning the tool much easier.)

 

5. Now gently grip the rivet. Do not squeeze yet.

 

6. With the spare hand, press very gently upwards the bottom skin next to the rivet. This is to ensure the upper and lower skins are together.

 

7. Squeeze.

 

8. Stand back and admire!

 

 

[MajorTom]

Hey Bob,

 

thanks for your reply. Surely I have read your different post about riveting a couple of times. One of the best part was: "dump the supplied solid rivets and by the real AN470 AD-3-3

 

But I must appologise once more for beeing unprizise and missleading. The "promissing rivets" you refer to in your first reply, are my old attempts with the supplied rivets. These are the rivets I will not use! The picture of them was for camparrison. Now everyting works great. Look at picture 4... this my shop head...picture 5 showes the AN470 head. My rivet set has domed heads on both sides.

 

 

[IBob]

Hey Bob,thanks for your reply. Surely I have read your different post about riveting a couple of times. One of the best part was: "dump the supplied solid rivets and by the real AN470 AD-3-3

But I must appologise once more for beeing unprizise and missleading. The "promissing rivets" you refer to in your first reply, are my old attempts with the supplied rivets. These are the rivets I will not use! The picture of them was for camparrison. Now everyting works great. Look at picture 4... this my shop head...picture 5 showes the AN470 head. My rivet set has domed heads on both sides.

Ah, very good!

So the domed heads align now on both sides???

 

 

[MajorTom]

Yes... they have no other choise

 

 

[IBob]

Yes... they have no other choise

So, the domed shop head is self-centering?

 

 

[MajorTom]

Yes, it is by design.

 

The pliers work parallel and are quite precise.

 

The main problem with the kit rivets is, that they are a little to thin and thereby very loose in the hole. Second problem is there sperical head instead of the doomed head of the original AN470. Third point is there lenght, its on the longer side of the rule. All in all, they are very wobbly and gave me a hard time.

 

....

 

No time to built these days... I have theoretical flight school every day and pactical hours til sunset as well...

 

 

[MajorTom]

Just fineshed my flaps. Had to pull out the rivets on the upper, aft ribs.... and rerivet with spacers betwen rib and skin. Also deriveted the solid rivets on 2 already finished flaps and replaced with AN470 rivets. Now I'm satisfied with the result.

 

Next step is to redo the solid rivets on the elevator and rudder.

 

 

 

 

 

 

 

[rankamateur]

.... and rerivet with spacers betwen rib and skin.

I am not sure about all the packing people put in, some use aluminium, others use epoxy fillers. The computers at ICP design the structure of the assemblies and the tensions on the sheets are part of the design, including the distortion of the sheets caused by the tension. All the fill and packing adds weight and changes the design. The ribs under the wing nose skins for instance are not designed to be smooth, nor the sheets on the ribs of the flaps and ailerons.

 

 

[MajorTom]

Thanks for the insight. That is something, I did not think about.

 

 

[MajorTom]

Today I'm a little suprised in a negativ way....

 

I asked ICP, if they would replace the left wing tip. The part was damaged, due to early taking it out of the mould.

 

They send me a new part. Unfortunately this one is even more bent and twisted than the first one. Also it is much heavier!!! The weight is 698g compared to 458g. The glass fiber is different. It is the cheapest stuff aviable. Solution is, I will rather repair the first wing tip and send back the heavy one.

 

NO BIG DEAL, BUT my cowling is made of the same glas fiber. Does that mean, it is also 50% heavier than needed???

 

What are your cowlings are made of? And has somebody have weighed his cowling???

 

 

[rankamateur]

What are your cowlings are made of? And has somebody have weighed his cowling???

July 2013 kit has the heavy white cowling, Aluminium wing tips and white heavy white molding for front third of tip. Soon after this they went to the clear light weight unfinished looking cowling and full wing tip of same material.

 

 

[MajorTom]

sorry again for being so unpreszise... excuse my english

 

There are different types of fabric....

 

Usualy used in planes is something like this Buy Glass fabric 163 g/m² (Aero, finish FK 144, plain) 100 cm online ✓ | R&G Faserverbundwerkstoffe GmbH - Composite Technology

 

To save a handfull of dollars they use something like this Buy Chopped strand mat 450 g/m², 125 cm, yarn titer 15 tex online ✓ | R&G Faserverbundwerkstoffe GmbH - Composite Technology

 

The result is a much heavier part with no additional strenght.... kind of 70's style

 

 

 

 

 

[rankamateur]

One style (heavier) has old style White Gel Coat finish and is much easier for new builders to achieve a satisfactory painted finish, The other(mush lighter) is opaque finish which is not smooth on finished surface requiring much more filling and sanding to prepare for paint. Since some people install one fuel tank in one wing and two tanks in the other, I am not sure that the difference in the weight would be of great concern.

 

 

[Kyle Communications]

My 2010 model kit the cowls were quite heavy...The aircraft had a nosewheel breakoff about 3 years ago and broke the cowl. The new one I got from ICP was much lighter but not gelcoated. As a point of interest we call the 2 types you show as glass matt and the other crappy one or "cheap one" is done from rovings from a chopper gun or we also call it "chopstrand". The matt is lighter and stronger but more expensive of course

 

 

[rmorton]

Hi Thomas,

 

ready top put the cowl on? I have some serious catching up to do! I am away on holiday at the moment but will have a go at weighing the tips and cowl when I get home. Out of interest is one layer of the woven mat enough for the tips and cowl? Is there any advantage in other types of mat such as carbon or kevlar? I would be interested in having a go at making some parts and will try like you did the fin and tail tips. Mine are a completely different shape to the fin and tail and need to be squeezed to make them fit.

 

On another subject did you get the electric trim? If so what type of connecting rod does it use? Mine has a ball joint and not the clevis that Ray Allen uses, just wondering why they changed it

 

 

[MajorTom]

Thanks Kyle for the vocabulary.... it is always hard for me to put my thaughts into english words.

 

Hi Richard, my lazy savannah builder from france... ;-) Good to hear from you.....You should be one week ahead of me.... ;-) Perhaps in some time, I can fly over in my brand new Savannah and give you a hand. I've never been to france. hihi

 

The tail tips are not to hard to do. The fin tip is a little bit to wide. I did it negativ in the plastic part and put it into a vise while curing.

 

One layer is absolutly not enough!!! This needs to be calculated accuratly. I used 3 layers of 163g matt on the tips plus some reenforcements on the stabilizer tips aft edge....

 

Carbon and Kevlar are fine materials but I don't thing of them as an improuvement in a cowling. Material mixes are difficult to calculate. Kevlar is not stronger than glass but can absorb much more energy. Carbon is very stiff but cracks without warning. I would not do a complete cowling in carbon.

 

What is a ball joint?

 

Can you put your glassfiber parts on a scale?

 

 

[MajorTom]

Weight of my cowling is 3,80kg for both parts. That's o.k. for a part of that size. The quality is very poor.

 

And Richard, I'm far away from putting my cowling on. I spent the last 6 hours prepearing the parts for chapter 13.... and I far from finished...

 

It is very convinient to have someone building the same chapter at the same time and helping each other.

 

 

[eightyknots]

July 2013 kit has the heavy white cowling, Aluminium wing tips and white heavy white molding for front third of tip. Soon after this they went to the clear light weight unfinished looking cowling and full wing tip of same material.

 

Today I'm a little suprised in a negativ way....I asked ICP, if they would replace the left wing tip. The part was damaged, due to early taking it out of the mould.

 

They send me a new part. Unfortunately this one is even more bent and twisted than the first one. Also it is much heavier!!! The weight is 698g compared to 458g. The glass fiber is different. It is the cheapest stuff aviable. Solution is, I will rather repair the first wing tip and send back the heavy one.

 

NO BIG DEAL, BUT my cowling is made of the same glas fiber. Does that mean, it is also 50% heavier than needed???

I suppose every gram counts in keeping the aircraft at 300kg. There does seem to be a large weight difference between one wing tip and another. And I can see why there is a weight concern with the cowl. A fibreglassed cowl may add kilograms (not grams) to the overall finished Savannah weight.

 

 

[rankamateur]

A Savannah does not crash with an extra fuel tank in one wing and not the other so I am not convinced that a few grams difference between one wing tip and the other will be terminal either.

 

 

[Kyle Communications]

I have a roll of the 163 gram twill matt I got years ago from RG in Germany when I was making RC model jets. I still have the molds. The glass is beautiful stuff much better than was available here at the time. I imported the 100mtr roll. I still use it here

 

 

[MajorTom]

I have a roll of the 163 gram twill matt I got years ago from RG in Germany when I was making RC model jets. I still have the molds. The glass is beautiful stuff much better than was available here at the time. I imported the 100mtr roll. I still use it here

That is my favorite brand too. They also had a very nice instruction book, I learned from in times whitout easy access to information on the internet.

 

 

[rmorton]

With mtow of 472.5kg with a parachute any weight saving is of interest. I will get the scales out on Saturday and report back.

 

I have to agree with you Thomas having you going through the same process with a fresh set of eyes and the tremendous support from all the old hands on here, has made this a very easy process so far

 

 

[MajorTom]

O.K.

 

Your are a very kind person. I hope to meet you some time...

 

I just had someone on my blog page, who wrote me how stupid I am to deburr all the parts. They would be hidden deep in the plane. No need to deburr all the many holes, because they would be rivited anyway.... Not building a moon lander .... just an UL Plane ...