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 Seawind Amphibious - Building tips

The following building tips and photos deal with the Seawind, a composite amphibious flying boat. These tips are primarily meant for builders of this type of aircraft but the principles may apply to similar projects. We will add to this page as we have the time.

Many of the photos can be enlarged by clicking them

Feel free to copy theses photos. If you need an explanation of some of the photos you can right click on them and select “Properties” and then where it shows the Address (URL) right click on it and then chose “Select all”. Right click the highlighted text and select "Copy". Paste this in an email by clicking contact Seawind 128, and I will respond the best I can.  If you would like any of the Seawind photos in higher resolution we would be glad to email them to you.  Return here to watch for additional posting. We have hundreds of photos, many which shall be posted on the membership site of ISPA.

Wing

This wing was mounted temporarily some time back and the position of the hole for the Flap torque tube was marked from inside the hull according to the location that the torque tube came through the wing root when extended from the mixer. The mixer was previously installed where we believed was correct. Some how the mixer placement didn't jive with the notch on the flap hinge. This can be seen in the second picture which shows the hole cut according to the notch and the black line underneath it, indicatings where the torque tube comes through the wing root. This means that the Mixer has to be removed and lifted up to accommodate the notch. It is recommended that the wings be installed using both the front and rear spar mounts  and then cut the hole in  rib "A" following the notch,  then use the torque tubes to help determine the location of the mixer. 

Pictures for this section will be posted soon

Aileron 

  Bell Crank Assembly
The following photos were taken after completion

We had been dreading bolting up our aileron bell crank assemblies. Ours are much thicker than the ones shown in the manual. Which means that the bottom half of the bracket nearly sits on the skin. How were we to get the holes lined up and the bolts in the lower portion of the brackets once we did? We put all the angles on and then the bell crank, which we snugged up tight. Once we put it in place we concentrated on drilling the top holes. Using clecos to hold it in place we the marked the bottom holes in the rib by using a blunted “Sharpie” felt marked and twisted it in each hole bracket to make a mark for drilling. For the holes in the aft edge of the wing we shined a bright light under the bracket and then from the outside were able to see where to drill. 
We have a saltwater kit and use Stainless Steel hardware but even so they are still magnetic. By placing the bolts on the end of a telescoping magnetic retriever we were able to easily insert the bolts into the holes while looking through the hole (reading glasses came in handy here). Tightening was done by using a ¼ ratchet with an extension from the inside.  The long 3/8" wrench helped to hold a couple of bolt heads that were difficult because of the angle made it difficult to use the ratchet. Using the fiber optic scope helped to guide the wrench to the bolt head.  I thought for sure that I would have scraped knuckles and be cussing up a storm but it was so much easier than it looked. Hope this helps. Oh yeah, don’t cut the hole for the push rod so much vertically, as it needs to be wider than tall. 
Note the reinforcement on the upper aft region this is to help counter the weakening caused by the push rod hole. In the future I would put this in the inside. Also because the ailerons are so extremely critical, we felt it prudent to use the backing plates on the rib mounting region to prevent wallowing. Further for the pushrod bolt we used a AN4-12 cad bolt rather than the an AN4C-14 because we wanted as much strength as possible here and some is lost by using stainless. We opted to coat the bolt with BOSHIELD for corrosion protect both before and after installation, and will add this to our periodical inspection and maintenance list. You may have notice that we used a 12 and not a 14 length because this worked best with the castle nut.  

We had glued our ailerons together many months ago built with a chord of 16.75"  and didn't bother to cut the flaps until we were ready to install the wings. The photos above show the trim tab lay out according to the manual, with an additional 3/8 of an inch added to it, as we knew the 3 inches was short. Even with the extra 3/8 of an inch  we did not get past the foam build up and probably should have gone about 4 1/4 inches.

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  Sponson

This picture shows the gap between the outboard end of the aileron  and the sponson and the length of the aileron in relation to the sponson.

These were sent in by SNA showing the corrections for the above situations:

    Click each thumbnail for larger mages.

And these shows how much higher the sponson sits above the wing skin and the proposed placement of the sponson under the wing joggle.

Sponson higher than wing skin requiring massive amount of fairing.

Proposed placement under the wing joggle. This should be stronger and have a more aesthetic value.

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Flapper Valves

The above photos show an aluminum flapper valve or anti slosh valve. These will allow the fuel to flow in one direction from cell to cell of the fuel tank . The first photo shows the expanding screw that will be holding them in place (remove the plastic retainers (yellow) as they they may deteriorate). The second photo shows the plug from the hole, temporarily mounted to the valve to help center it for the mounting screw hole drilling.

Above we have the flapper temporarily mounted using duct tape and the the finished product mounted and tested.
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