The dreaded wiring....

Got quite a bit done this month. First of all I continued my paranoid sealing of the landing gear legs. As mentioned on an earlier post, many early Seareys allowed water to pour all over the inside of the hull as the gear retracted. I thought this was a crazy scenario so I have gone overboard on making sure this doesn't happen to mine and to ensure that the legs don't corrode from the inside out. I have now sealed the bottom of the leg with a rubber stopper, sealed in with Sicaflex.


bottom of gear leg with stopper

I also filled the spindles up with Sicaflex as I didn't want water getting trapped inside and corroding but before I did that I painted the outside with zinc chromate etch primer and coated the inside with 2 pack paint.

Spindles filled with Sicaflex

The next step is one of the hardest of all... the dreaded wiring! Luckily Rob Loneragan from Searey Australia supplies a list of what wiring is required and the wire gauge. I bought some aviation grade wiring a few months ago so I had it available when I needed it. As you can see from the folowing photos it looks like spaghetti spewing out of the frame and it took quite a few hours to complete...

Fitted the fuel sender...



Once the wiring was completed I thought I better make sure the landing gear system still worked... it didn't.. I traced the fault back to the electric actuator not being plugged in properly. In fact one of the terminal lugs in the plug wasn't locked into position properly so once that was fixed the gear worked perfectly.



However I wasn't really happy with the way that the crimp terminals on the wiring were just pushed onto the lugs on the relay. Aircraft suffer from a lot of vibration and I felt that after a while that one of the lugs would work itself loose and if just one of them did the gear wouldn't work. I decided to fit relay blocks where the wires are pushed into the bottom of the block and the relay plugs into the top of the block. The terminals in the block are held in with a small clip (and the relay terminal) so it is very unlikely that any wires could work loose.




As it is getting very close to fitting the frame to the hull I thought I would go around and check tighten all the nots and bolts that may be difficult to get to when the frame is in. After tightening I used a special marking paint called torque tube to mark that the nut had been tightened.



More sealing of the gear legs... even though I have coated the legs and spindle housings TWICE with 2 pack paint, I thought that some linseed oil poured inside as well couldn't hurt!




Drilled a drain hole for the baggage compartment including some stainless steel mesh to stop small objects falling through...




I fitted the spindle housings to the gear legs and sealed them well with sicaflex so the only water that should enter the gear leg assemblies is throught the drain hole in the housing however it can't get into the leg due to the rubber stopper.



Last thing for this month was ground bonding the fuel tank.. not sure if wire gauge is big enough so will check that out.



The frame WILL be in the hull next month!

Getting there.....

There is a very good internet forum specifically set up for Searey members. It is a place where any member can go and post photos or details of their latest idea or post a question about how to do something on their Searey. It is a wonderful resource and building the Searey without it would be much more difficult. Every day I am getting good ideas of how to make my Searey better and safer. One tip that has helped me over the last few weeks is to try and get as much done on the fuselage before it is fitted into the hull. If the fuselage is fitted into the hull too early there are many things that would be quite difficult to do such as some of the wiring, controls and landing gear. As time goes on I can see that if I had followed the procedures in the Assembly Manual I would have had the fuselage in the hull by now but it would certainly be more difficult from here on.

Anyway its been a productive month.... first of all I fitted the aileron torque tube. This tube is what operates the ailerons instead of cables. It seems like a good idea however I have some reservations regarding the "feel" of the controls as they seem quite "sticky". I assume this is normal and should feel quite different once the wings and ailerons are attached.





Another mod I decided to do was to add straps to either side of the tailwheel mounting assembly. This mod was recommended by Rob Loneragan from Searey Australia. It helps stop movement from side to side and is well worth the time.





Even though I am a spraypainter by trade, I don't really have the proper facilities to paint something like the hull especially to produce a good finish so I sent it down to the local paintshop.They did a great job and it looks very flash!



I thought it would be a good idea painting the interior of the hull for 2 reasons. Firstly the carbon fibre hull is a very dark grey colour and when the top section is fitted it will be very hard to see in the hull for inspections. Secondly, it seals back the carbon fibres which are very sharp and easily penetrate the skin. As it doesn't matter what the finish is like (even though it did turn out OK) I sprayed it myself. OK so it adds a little weight but I only sprayed on a couple of light coats... and it looks great!



Whacked in some bungs....





and added a stainless steel skid plate... this is in case I ever forget to put the gear down or the gear fails to extend and I have to land on a hard surface.... again it adds weight but it's better than wearing away a very expensive carbon fibre hull!



Fitted carpet into the hull including sewing on some pockets for storage of maps etc....





One of the most bizarre things regarding the landing gear on a Searey is that most builders seem happy to allow water to run through the gear legs into the hull and all over the bulkhead and electrics etc etc when the gear is retracted. When I first heard of this I couldn't believe that someone hadn't come up with a solution. I then read a few posts on the Searey site how a few builders were coming up with all sorts of ways to stop this occuring but I wasn't really happy with most of the solutions. I had a think about it myself and came up with the following. First of all I had bushes welded into the bottom of the gear leg where the spindle housing bolts on so that even if water was forced through the bolt and nut heads it couldn't get into the leg. I then found a rubber bung (chair stopper.. $2 for 4) and inserted it into the bottom of the leg with Sicaflex. Before doing all this however I coated the insides of the legs and all wheel parts like the spindle housing with 2 pack paint so in case any water does get in it will slow down the corrosion. The good thing about Sicaflex is that the bungs can be removed for inspections down the track.

coating inside gear legs etc with 2 pack

I have also sealed the sleeve that slides over the gear leg where the pivot bolt goes with Sicaflex so that there is no way water can now get into the leg and run into the hull.

bottom of gear leg with bung and Sicaflex

repainted the gear legs and spindle housing etc with 2 pack.



fitted checker plate to the heel rest area. You would think that it is a good idea to allow your heels to slide when using the rudders however I have big feet and don't believe I need them to slide. If this isn't the case once I start flying they can always be removed.



I had a big think before deciding what to do about a baggage compartment. Rob Loneragan from Searey Australia builds his from wood behind the passenger seat which I also intended to do however I changed my mind and made it out of aluminium. I know it weighs a little more but I really wanted something tough that will handle heavy tool kits etc thrown into it. I really don't like building things that are fragile and need to be handled with kid gloves so I am sure this was the right decision.. time will tell!



I then trimmed it with the same marine carpet aa the hull.... very spiffy!



Hoping to get a lot done in June including the wiring for all ancillary things like fuel pump, bilge pump, trim etc before fitting the fuselage to the hull... that will be exciting!

April '08

This month I got quite a few things done including fitting the fuel tank. It's an interesting method of fitting the tank using seat belt webbing to hold it in place. Although that sounds dodgy its actually quite ingenious and seems to work really well. It is important though to soak the webbing in water overnight so it will shrink when dry to ensure a tight fit. After the preliminary fitting last month and looking at how it sits in the frame, I also decided to add some small angle brackets to stop any sideways movement. I thought that with approx 60kg of fuel in a full tank that in flight there may be some sideways movement and didn't think that the straps would stop movement in all situations





I also fitted the upper root tubes and engine mounts...



finished off the fuel system...



Fitted the vertical fin and part of the tailwheel assembly...





The control sticks, aileron bellcrank and tie rods and throttle lever...





I also started on some wiring as it is a lot easier to fit before the frame is bolted into the hull. I started with the electric gear system using the supplied microswitches. I really didn't want to use microswitches instead going for a current relay but just couldn't find one to suit. The microswitches work well enough and because I have modified the actuator system so that the retraction bars can no longer be pushed through the lower bulkhead if a switch fails, I am happy with the outcome. I am also considering installing a back up system where I wire a switch direct to the actuators by-passing all relays, switches etc so that in the event of a failure I can get the gear down. Will keep you posted on that one. For those interested in electrics, I have included a wiring diagram below.







Next month I hope to finish the wiring and maybe even fit the frame into the hull so we'll see.

March 2008...

Again its been a little slow this month but at least I have finished the electric gear and am very happy with the results. Last month I mentioned I was going to make some new brackets for the retraction bars to not only get more over centre, but to make sure that in the event of a microswitch failure, the retraction bars don't get pushed through the lower bulkheads. This has finally been achieved by making new brackets and repositioning them on the retraction bar as shown in the below photo...
Click photo to enlarge
You can see that there is now enough over centre and that when the actuator is fully retracted, the upper bars fit snugly on the spacer pad.

The photo below shows the position when the actuator is fully extended. Note that the retraction bar cannot now be forced through the lower bulkhead if a microswitch fails.
Click photo to enlarge
I am very happy with the end result however it has taken me 25.5 hours to get to this point. Time will tell if it was worth it!

Also this month I did a preliminary fitting of the fuel tank. It is quite a unique way that they have devised to fit it. The all aluminium fuel tank is actually designed and made in Australia by the Searey Distributor. Rob Loneragan. Apparently the original tank made by the manufacturer was made of plastic, was smaller capacity, and had issues with deformation and leaking.

Hope to get a lot done in April.

Month number 2...

I haven't really got a lot done this month due to to being busy with other things in my life such as working on the house and getting some new dogs. Its been just over a year since we lost our precious little dog Chloe who was 18 when she died in her sleep after a long illness. We still haven't got over the loss but the 2 new ones should help. We picked them both up from the RSPCA and the border collie cross, Ki-Ki, is approx 12 months old and the little fox terrier cross, Sooty, is 10 and a half years old. Ki-Ki was found wandering the streets and Sooty was surrendered by her owners as they were moving into an apartment that didn't allow dogs. How you can hand in your pet after 10 and a half years has got me beat but humans will be humans.



Anyway onto the Searey. I have spent a lot of time on the electric landing gear this month trying to modify it for a couple of different reasons. I mentioned last month that I wasn't happy with the amount of over centre with the gear fully extended. (see photo below)

Click photo to enlarge
Even though the electric actuators would hold the legs from collapsing in the event of a bumpy landing etc, its really not the correct way to engineer it. I am also not happy with the possibility that the retraction bar would be pushed into the lower bulkhead if a microswitch failed when the gear is retracted possibly warping or breaking something... not a nice thing to happen in flight! See photo below to get a better idea of what I mean...

>Click photo to enlarge
After both sides were assembled and operational I called another local Searey builder, Paul Williams, to have a look at it and get his opinion. Paul has a lot of engineering experience having invented and patented a unique drying furnace among other things and of course building his own Searey. He suggested we check out how much travel the actuators have in each direction so we can establish if we can move the bracket on the retraction bar to get not only more over centre, but at max extension to make sure it will hit the internal limit clutch before deforming the bulkhead or breaking something else. After a preliminary measure up we now believe this is achievable.

In March I will be making new stainless steel brackets that attach to the retraction bars to see if I can achieve the above result. Unfortunately these modifications hold up the building of the rest of the Searey but it is well worth it to get such an important part of the aircraft as good as possible. There has been many cases of Searey undercarriages failing on either landing or taxiing so I am determined to make sure mine is not one of them.

Will update this blog when the gear is modified to my satisfaction.