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Old Oct 03, 2012, 03:26 PM
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Looking amazing Trevor.
How many man hours do you think are already in this airframe?
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Old Oct 04, 2012, 11:36 AM
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Originally Posted by pentaxman View Post
How many man hours do you think are already in this airframe?
Well, the build started 12 days ago and I can rarely manage more than 2-3hrs a day in the workshop so probably no more than 30hrs invested so far. That's not counting all the time spent in 'off line cogitation' over the various build decisions of course.

False leading and trailing edges are now in place so I'm just tackling the job of planing and sanding them down to align with the ribs - I've only broken one rib so far. . .
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Old Oct 09, 2012, 04:32 AM
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All Joined Up

Well, it's taken four days, but the inboard wing panels are now well and truly joined. As has been mentioned earlier, the Aquabird effectively lands on its wing tips so this central joint has to take landing shock loads rather than just the aerodynamic stresses. It feels nice and solid now though - time will tell!
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Old Oct 17, 2012, 09:43 AM
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I wonder whether the continued silence here indicates that others sometimes find wing building as boring as I do? That's one reason why I tend to build the wings first so that, as enthusiasm begins to wane, there is always the prospect of a more interesting fuselage build to spur me on.

Anyway, this build is still inching along. Leading edge D boxes are now sheeted and the leading edges themselves are fitted. Final shaping will be left a while though to provide some protection against hangar rash.

Trailing edges next, which forces another decision - how to build the ailerons?
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Old Oct 18, 2012, 02:39 AM
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The wing looks different in configuration from different angles - a sort of optical illusion. You're not the only one struggling Trevor!
At a glance the wings in pic1 and 3 look completely different... but I imagine it'll start to settle down once a fuselage offers some kind of visual reference line...

So where are the ailerons situated? Out beyond the floats?
(Thoughts of servos in floats and all-moving plug-in tips)
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Old Oct 18, 2012, 04:54 AM
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I think the optical illusion is so strong because everything about this wing is the opposite from what we have trained our brains to expect - i.e. forward sweep and anhedral. I find it very difficult to look at that first picture and not see sweep back in the leading edge. As you can see in the other pictures, there is none.

The ailerons keep up this 'not what you expect' tradition - they occupy the inner 3/4 of the inboard panels. The tip sections were added after early flight trials so the all-moving tip idea wasn't an option in the original design. I did contemplate shifting the ailerons outboard a bit, since I will be using separate servos rather than the single central servo of the prototype. However, because of the anhedral, the inboard location does at least mean that they are well clear of the water and Laddie assures me that they work okay, so I have kept faith with the designer on this point.

As for the construction, the ailerons are just labelled '1/4in balsa', which is odd because the depth of the false l.e. tapers from 5/8in to 1/2in!
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Old Oct 18, 2012, 08:07 AM
TonyS
United States, AR
Joined May 2010
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Trevorh,

First, I think lack of messages may not be due to lack of interest so much as not so many folks visit the Exotic and Special Interest forum, and like myself may be awaiting a point of progress at which to interject informed comment. For example, now I can commment...if it were my build I would ensure the ailerons continued the wing tapering; thick as wing trailing edge on the aileron leading edge, as on Laddie's original design.

I flew a friends Aquabird many times during the past three years. Laddie's aileron layout works quite well. I have performed many relatively tight rolls with his Aquabird, with a little help from rudder and elevator input as with any non-aerobat design. Unfortunately, a battery failure ended the plane last month, just too many pieces. At age 80 he has decided not to do another, but I have since purchased plans and added Aquabird to my build list; even put it ahead of my North Star kit.

I will continue to follow your build with interest.

TonyS
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Last edited by tonystro; Oct 18, 2012 at 08:16 AM. Reason: to add a point
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Old Oct 18, 2012, 08:58 AM
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Quote:
Originally Posted by Trevorh View Post
I think the optical illusion is so strong because everything about this wing is the opposite from what we have trained our brains to expect - i.e. forward sweep and anhedral. I find it very difficult to look at that first picture and not see sweep back in the leading edge. As you can see in the other pictures, there is none.

The ailerons keep up this 'not what you expect' tradition - they occupy the inner 3/4 of the inboard panels. The tip sections were added after early flight trials so the all-moving tip idea wasn't an option in the original design. I did contemplate shifting the ailerons outboard a bit, since I will be using separate servos rather than the single central servo of the prototype. However, because of the anhedral, the inboard location does at least mean that they are well clear of the water and Laddie assures me that they work okay, so I have kept faith with the designer on this point.

As for the construction, the ailerons are just labelled '1/4in balsa', which is odd because the depth of the false l.e. tapers from 5/8in to 1/2in!
Trevorh
You doing great job. I am following your progress. As far as the thickness of the ailerons go, on original plans and the article published in RCM magazine the ailerons were cut out from completed wing and the hinge spars and the leading edge spars were glued to them. I am enclosing the page from the original article. Read second last sentence on this page.
Good luck. Laddie.
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Old Oct 21, 2012, 09:59 AM
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Tony, Thanks for the comments and thoughts about the aileron arrangement. Although I didn't doubt Laddie's assurance that the inboard arrangement works okay, it's always good to hear another pilot's first hand testimony.

Laddie, As you know, I have been treating the drawing of the built up wing option with some suspicion from the outset, but I still find it astonishing that somebody could draw the ribs as they are and then suggest ailerons only 1/4in deep. Maybe if they had drawn one or two typical wing cross sections, they would have spotted the inconsistency.

Anyway, as you may have guessed from the stack of 1/16in balsa in my last picture, I have decided to build the ailerons from two skins of 1/16in balsa with 3/32in balsa riblets in between. It's all a bit fiddly but the resulting ailerons should be lighter (and probably stiffer) than the solid balsa approach.

Incidentally, a few days ago I suddenly realised that I have been happily building the Aquabird using Titebond Original. Although this is a perfectly good aliphatic resin glue, but it is not very water resistant. Hopefully there should be little risk of water ingress into the structure built so far and I now have some Titebond 2 ready for the sponson area and the tail end of the fuselage.
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Old Oct 26, 2012, 10:11 PM
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Cool. Been looking at a seaplane like this. Was thinking about the Polaris but this sure made me turn my head.

Good luck.

~B
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Old Oct 27, 2012, 03:39 PM
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Ailerons completed - almost!

The servos are now installed and linkages sorted so the ailerons have been closed up and the underside trailing edge sheeting applied to the wings. Hinges and horns are of course only dry fitted at this stage.

The inboard ends of the ailerons will need 'facing and spacing' once the fuselage is built and the wing mounted. I'm also deferring sheeting the centre section until the wing fixing has been sorted out so, unless I decide to do a bit of rib cap stripping, it's beginning to look like it's time to roll out the fuselage plan. . .
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Old Oct 27, 2012, 05:50 PM
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Trevorh. Normally I do not try to correct someone building model of my design, but this time I have to if you planning to fly off the water. Looking at the pictures showing the location of the aileron servos and how you routing the pushrods I see big problem. The opening in the hinge spar for clevis will allow the water to pour into the wing. As you can see from the picture, while taxing whole trailing edge is touching the surface of the water. On my Aquabirds, the servo is mounted right side up in the wing and two flexible pushrods are installed from inside servo box to the bottom of the wing as shown on the photo and the drawing.
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Old Oct 28, 2012, 05:04 AM
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Thanks Laddie, a timely warning! I had hoped that the anhedral would keep the inboard section of the wing clear of the water and it would only be exposed to spray. However, I can see from the picture that, in a nose up attitude, the sweepback negates the effect of the anhedral. I shall have to give this some thought!
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Old Oct 28, 2012, 06:41 AM
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I am showing you option I took on my present Aquabird. I use 1/8 carbon fibre rods. I never had any problems with the water hitting the servo.
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Old Oct 28, 2012, 01:19 PM
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And presumably a plastic fairing over the servo would be in order?

The Aquabird is remarkably like a number of ekranoplan designs so the air pressure under the wing should work to good advantage.
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