Unleashed Experimental amphibious aircraft build update

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michael Hille

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Aug 14, 2019
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71
Amazingly rapid and interesting fabrication. Are these mechanisms designed on the spot?
Thanks for that , these mechanisms I designed in CAD first prior to building , the whole plane was designed on CAD before I started building .
 

michael Hille

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Joined
Aug 14, 2019
Messages
71
Thanks for that , these mechanisms I designed in CAD first prior to building , the whole plane was designed on CAD before I started building .
My design was for simplicity of building which is why this project is going together so quick .
 

NOLA

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Joined
Apr 26, 2020
Messages
15


Watching the update. Is there a single thread where these are posted and discussed? Nice work btw.
 

pylon500

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Supporting Member
Joined
Dec 26, 2003
Messages
590
Location
Taree Airport Australia
Only stumbled on this, and I feel compelled to make few suggestions...
As you pointed out in your last video, you need to rearrange the sponson layout as without any crew on board it sits low in the tail, and if you step back there to daily the engine it will get worse.
Solution, (as you said) more sponson volume behind the CofG, and I've figured a way you can do this around the main gear.
Basically you will end up with two sponsons per side, being a front and rear half, with a slot for the gear to come down through.
Make the front sponson deeper at the rear to for a step in the right place relative to the CofG, and simply use a spring loaded gap seal, pushed in by the gear leg, to clean up the aerodynamics around the sponson in flight.
The rear section could be quite large to give plenty of floatation behind the empty CofG without creating much drag. It's trailing edge could also be sharp, but maybe only 1" deep would be ok.
Screen Shot 2022-07-23 at 5.59.44 PM.png
(Please excuse my crappy 5 minute scribble)
 

Riggerrob

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Joined
Sep 9, 2014
Messages
2,833
Location
Canada
Only stumbled on this, and I feel compelled to make few suggestions...
As you pointed out in your last video, you need to rearrange the sponson layout as without any crew on board it sits low in the tail, and if you step back there to daily the engine it will get worse.
Solution, (as you said) more sponson volume behind the CofG, and I've figured a way you can do this around the main gear.
Basically you will end up with two sponsons per side, being a front and rear half, with a slot for the gear to come down through.
Make the front sponson deeper at the rear to for a step in the right place relative to the CofG, and simply use a spring loaded gap seal, pushed in by the gear leg, to clean up the aerodynamics around the sponson in flight.
The rear section could be quite large to give plenty of floatation behind the empty CofG without creating much drag. It's trailing edge could also be sharp, but maybe only 1" deep would be ok.
View attachment 128007
(Please excuse my crappy 5 minute scribble)
You don't need to retract the main landing gear leg completely above the sponson (aka. water wing). You could retract the main wheel into the sponson. If the main wheel well is aft of the step in the strut, you may be able to delete doors. That will allow you to leave the top skin of the sponson intact, eliminating one trip hazard.
When we only expect small amphibians to cruise at 100-ish knots, the finer points of streamlining become trivial. Either way, it is important to provide plenty of drainage and venting to quickly dump any water remaining in wheel wells.

Or you could just lift the main wheel above the water-line. If the tire protrudes from the outboard rib of the sponson, you can use it as a fender when docking.
 
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