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Likes: Two 4' X 8' sheets of one-inch plywood on spreader bars: any negative aerodynamic effect? I've carried lumber, boats, bales of insulation with no noticeable effects on SC and 0360 Bushmaster but wanted to check here. Thanks.
Two 4' X 8' sheets of one-inch plywood on spreader bars: any negative aerodynamic effect? I've carried lumber, boats, bales of insulation with no noticeable effects on SC and 0360 Bushmaster but wanted to check here. Thanks.
In my experience speaking with ?...put 4-2x4's front to back over the upper spreader bars and X-wires flat with the outermost sideways against the bottom of the struts and rear ends just aft of the rear spreader bar. Put the plywood sideways across the float tops and 2x4's. Stagger them bottom piece to meet front strut and top piece (of the staggered stack of how many you want) back to rear strut as required to meet CG and GW limits. Screw them to the 2x4's and each other. Put binder straps (3 minimum) or nylon ropes (they dry and tighten as you fly) front to back around the whole assembly. Now you have a pan that can't move sideways, back, or break up as up at front is bad drag...(I might know someone who did this once). Any large overhang past the rear spreader on EDO 2000's at least and I assume others will slow getting on step due to drag but the water can and will flow between the rear spreader and 2x4's ok.
In the air (I hear) the load don't exist on calm sunny days providing the CG is within limits.
Gary
skukum12 liked this post
Gary’s recommendation works fine. Also, try to keep the pitch attitude on landing relatively flat....just no big pitch up. That plywood can aerodynamically brake some.
One reason for the two by fours is to keep the plywood from interacting with the spreader bar to create an air dam, as well as permitting you to mount the plywood crossways to aid.
MTV
I might mention another thought. The plywood doesn't have to span the space from front to rear float struts if CG is out of spec as a result. The rear staggered sheet(s) edge can terminate forward of the rear float struts to adjust CG and if water drag at the rear spreader becomes a no-go event. If so then at least two binder straps should wrap around the plywood pan and front spreader bar to keep it from moving back and up, and two more around the same pan and both front and rear float spreader to hold it all down. Discard any frayed or compromised binder straps. Wider straps are better than narrow.
Staggering the sheets front to back on top of each other reduces the leading edge bluntness some and drag in the air. Some add an airfoil-like leading edge to the plywood pack but the stagger works ok. Test.
Mike's right about the 2x4' base (or larger 2x? boards if needed at the construction site) allowing the flow if air in addition to water between the spreaders and plywood. It does make a difference.
Use lots of screws to stick everything together. Their holes are inconsequential when building.
Gary
Last edited by BC12D-4-85; 10-22-2017 at 03:13 PM. Reason: changed strut>front spreader bar in text
Thank you. All good advice. I will follow it.
Back in the day I heard of a young guy helping someone out by flying their cabin materials into a pond out by Lake Louise
Now said pilot had a 180 hp cub, and less guidance than one can get these days from the internet. So upon arrival the first load was with the guy building the cabin, and a few pounds of stuff on the spreader bars, and maybe even a little gear behind the seats
As the first landing came to a displaced hull status, a quick right turn was used to prevent a beached aircraft- the wingtip was over the bank in the turn.
Ten or twelve loads later the entire cabin was stacked on the shore, including one load of 10'x4' T-111, and I think that was 12 or 14 sheets in the load.
My understanding, as the T-111 was strapped directly to the spreader bars, getting the plane on step took quite a bit of room because the wood restricted rotation out of the water getting out of the plow. The 180 hp compensated and muscled the plane up. Once on step it was a no worry flight- until it was time to land.
On approach the plane did not like slower airspeed. (before VG's were a big deal). The plane could not be brought under about 60 without a buffet, so having a short lake and high speed was a bit of a challenge-
That was the first pilot to take a passenger out of that lake, and the entire project went well. Knowing the plane was a big deal, and knowing how far you can push forward on the bows saves quite a bit of brush cutting.
In calm weather I don't think plywood is a big deal to carry- but tight spaces requires a bit more planning and skill
At least that is what I was told by someone who shall remain unidentified!
I don't know where you've been me lad, but I see you won first Prize!
Why do we see most of the loads on the float rigging rather then on the floats spreader bars? Any inconvenience?
If the load fits under the tie wire X and doesn't cause water drag behind the rear spreader it works. Getting it in there from a dock might be work. On foot no problem.
Gary
Yes, it’s a lot easier to load and secure stuff to the vertical struts. And the little bit of differential drag is hardly noticeable.
MTV
Lots of water moving between the spreader bars in the plow. Anything behind the rear one will be in the water causing drag.
Yes, it works, but takes more time and power to get on step, and settles down a little different.
I don't know where you've been me lad, but I see you won first Prize!
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