amateur built floatplane question

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Bede
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Re: amateur built floatplane question

Post by Bede »

ruddersup? wrote: Sun Jul 18, 2021 5:42 am Whatever you do close to the ground other than straight and level, I hope you are thinking is this necessary.
I'm rarely in level flight close to the ground. I'm usually descending on landing.
ruddersup? wrote: Sun Jul 18, 2021 7:52 am Would be nice if the whole industry complied like you suggest must, but.......... I would think that there is not an aircraft flying that meets regulations 100%
Mine does.
ruddersup? wrote: Sun Jul 18, 2021 7:52 am the industry would be grounded in a heartbeat if that were true.
If that's the case, then maybe it should.
ruddersup? wrote: Sun Jul 18, 2021 7:52 am I disagree with you saying you were PNF. Giving out a rating would require you to not allow the aircraft to ever get into an event that happened to you.
If you are a qualified flight instructor you should understand that. If the plane crashes it's the instructor's fault - nothing to argue there but if the tail falls off then I'll listen to your side.
I'm an instructor too and I've seen how fast someone can do something unexpected and there is nothing you can do. PilotDAR is probably the most helpful & knowledgeable guy on this forum. To rub his face in something crappy that happened is beyond the pale. You come on here, ask for advice, helpful advice is given by knowledgable people, and then you turn on the people who have more expertise than you (you were the one asking the questions, remember). PilotDAR's too classy to call you out on your douchbaggery, but I'm not: you're an asshole.
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ruddersup?
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Re: amateur built floatplane question

Post by ruddersup? »

Bede - Everything I've said is IMHO. I did not call him out as you suggest. It's goes with the territory that the instructor has control of the situation. Ask an insurance company.
Incidentally I have known Jim longer than you have probably been alive and he has been to my facility many times. As a matter of fact I'm hoping to hire his services but please don't tell him.
All said is educational for people who do not beat their chest so delete this whole thread, it's not suitable for you.
Your age is showing - try to show some class, son.
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Bede
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Re: amateur built floatplane question

Post by Bede »

ruddersup? wrote: Sun Jul 18, 2021 4:07 pm Your age is showing - try to show some class, son.
OK Boomer 8)
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rigpiggy
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Re: amateur built floatplane question

Post by rigpiggy »

Has anyone tried the inboard end plates on the ailerons as a way to increase roll stability?
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Delta22
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Re: amateur built floatplane question

Post by Delta22 »

just to piggy-back on this forum, I know that the Beech model 18 had floats and therefore had a ventral fin added for the extra stability (something I didn't know until coming to this forum) but one thing I wonder is:
would it be feasible to instead increase the size of the vertical stabilizers on the Model 18, as its a twin tail aircraft?

alternatively, what would happen if you were to create a flying boat based on the Model 18 design? Would you *have* to increase the fin size, as there isn't really the potential to add a ventral fin.

(this is all hypothetical)
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photofly
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Re: amateur built floatplane question

Post by photofly »

Ventral (and dorsal) fins have a low aspect ratio and provide slip-yaw coupling at high side slip angles, angles where the vertical stabilizer would be stalled.
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DId you hear the one about the jurisprudence fetishist? He got off on a technicality.
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PilotDAR
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Re: amateur built floatplane question

Post by PilotDAR »

Increased vertical surface area is commonly needed to offset the aerodynamic effect of the forward portion of the floats. In Cessna 180 series planes, water rudder system friction also can effect the freedom of the rudder to move, and return to center when released (directional stability). A directionally unstable plane is simply unpleasant to fly, and can be spin prone during the approach to a stall.

You cannot assume that the structure of the airplane (and in the case of the Beech 18, the H stab) is adequate to carry the additional loads which could result from increasing the V stab(s) height. Remember that if this vertical surface is added, the loads that surface could generate will be transmitted into the fuselage, and must be safely carried.

The addition of a ventral fin is generally a structural easy do, and if you have the damage a flying surface, that'd be the easiest and least costly to replace. H stabs sometimes have finlets added, which is generally okay, though can add some complexity around elevator moving parts, and I have known them to hum in flight, which is not great for fatigue of structure.

If this characteristic of a plane is inadequate, to a point, pilot effort and skill can mask the negative handling, but manufacturers (like Cessna) tend to do the testing to optimize this. I have test flown a couple of modified C 180 and 185 floatplanes where the ventral/dorsal fin set up was wrong, and they were a misery, with one being so bad, it was truly unsafe, and I "watered" it after the first flight, until changes were made.
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