Mead 1430 Amphibs on 11-EX

[Dan Gervae]

The only thing that makes me feel like this, although not a perfect design…is the fact that not only is there a very robust deck plate with 4 bolts going through an impressive structure….also the wire pull attaches to the AN6 bolt and the flying wire attaches there and back up to the fuselage fitting on the other side which will carry a lot of that load path…it’s the same on the rear fittings. Aerocet actually has a similar fitting, only the wire is attached to the 2 bolt deck plate. here are some photos.

mead wire pull

Aerocet 1500 floats design

[skywagon8a]

Look again at your rear float deck fitting and the alignment of the load paths with the deck fitting. Remember all of the landing loads are compression in nature through the struts in a straight path between their attachment bolts continuing straight through the bolt location. The junction of those multiple extended paths should all come together in the same location. Due to the vertical down force on every landing, the geometry of the front and diagonal strut will be attempting to expand the base of that triangle. The diagonal strut will be pushing the top of deck fitting aft. The rear strut will be pushing down behind the deck fitting. These two forces coupled together will be trying to roll/twist/peel the deck fitting aft. The resultant loads will be trying to break the deck fitting at it's forward side where the thin flange extends forward being held to the float deck with the two bolts. The rear side of that fitting will be trying to bend aft. IF you were to change the fitting which connects the two struts to the float deck fitting so that the two strut load paths are directed at the center of the float deck fitting, those destructive loads will be eliminated.

The cross wires are in tension and their only purpose is to maintain the alignment of the floats to the fuselage.

Attachment 61403.

[Dan Gervae]

Baumann did the same thing. They got the front fitting right though.

[skywagon8a]

I see why you did it the way you did. Why Meade and Baumann both did it contrary to proper engineering practices, I can not say. They both should have known better.

[Dan Gervae]

closer by the day

[Dan Gervae]

Now I need to wire controls…fabricate rudder retract cables, do weight and balance etc.

[Dan Gervae]

taxi tests show I need more nitrogen in front shocks ….it’s a bit of a pain to do too. After a setback with a major infection in my foot I finally got this done. Will report flight tests as weekend goes on

[Dan Gervae]

this just happened…almost taxied into a hanger….bummer. These were new stock Scott masters .I don’t feel too great about the other one now either. Not good. I was stepping pretty hard to turn on the amphibs, but this could have been trouble on a landing possibly

[Gordon Misch]

Ugh! Maybe look into Grove masters, the form factor is the same and very well built. Dunno how compatible they'd be with your wheel cylinders in terms of fluid displacement, but I bet Robbie Grove would.

[skywagon8a]

That brake failure is a bummer. It's good that it happened when it did and not when you really needed the brakes, as scary as it was. Was that an actual Scott master cylinder or a Chinese pot metal copy? I know it's a lot of work, but you could make one. I made one out of solid aluminum.

Amphibs do require a lot of dependable braking capabilities. The smaller the wheels, the greater the pressures required since the small diameter disk has less mechanical advantage. You have 5" wheels which are the worse. I suggest you add another brake disk to the other side of the wheel along with the appropriate wheel braking unit. Plumb the two sides together with a "T" in the brake line. I did this to a set of EDO amphibs which had 5" wheels. It made all the difference. Raisedbywolves has these floats now.

Also your nose strut needing air could contribute to the steering issues as the angle of the pivot can make turning difficult. It wants to keep going straight.

[RaisedByWolves]

That brake failure is a bummer. It's good that it happened when it did and not when you really needed the brakes, as scary as it was. Was that an actual Scott master cylinder or a Chinese pot metal copy? I know it's a lot of work, but you could make one. I made one out of solid aluminum.

Amphibs do require a lot of dependable braking capabilities. The smaller the wheels, the greater the pressures required since the small diameter disk has less mechanical advantage. You have 5" wheels which are the worse. I suggest you add another brake disk to the other side of the wheel along with the appropriate wheel braking unit. Plumb the two sides together with a "T" in the brake line. I did this to a set of EDO amphibs which had 5" wheels. It made all the difference. Raisedbywolves has these floats now.

Also your nose strut needing air could contribute to the steering issues as the angle of the pivot can make turning difficult. It wants to keep going straight.

Make sure you secure the line really well. Had a landing at home on the grass and the zip ties broke, wrapping the hose around the wheel. That side locked up. I had a wtf moment followed by locking the other side. Now there is a stainless steel zip tie and a couple plastic ones. Good thing it was on grass. The brakes work really well. Keep the nose wheel grease new and clean, the nose wheels work better that way


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[Dan Gervae]

These were new Scott masters purchased back in 1995 and sat in a box. I did push the left brake pretty hard, but I was sure surprised when I heard the snap and I veered right headed for the neighbor hanger. A quick mag shut off and I coasted toward it and stopped wheew. I have access to another Scott master(used from a PA11) from buddy Tom. I’ll fix things up and try again…the north river boosters helped a lot….maybe I stressed my brakes before just trying to keep from rolling on run up…who knows

[skywagon8a]

It's difficult to see in your photo. Is that a AN-3 bolt which is being used for the pedal hinge? If so and it was tightened, it could have placed a sideload on the two cast fingers which broke. Either use a clevis pin or leave the bolt loose so that it will rotate with your fingers.

[Gordon Misch]

The smaller the wheels, the greater the pressures required since the small diameter disk has less mechanical advantage. You have 5" wheels which are the worse.

Not arguing, but expanding on this a little bit; the ratio of brake disc diameter to loaded tire diameter is what matters. If that ratio is smaller (i.e. smaller brake disc or larger tire) then greater pressure is required for comparable braking action.

[frequent_flyer]

Not arguing, but expanding on this a little bit; the ratio of brake disc diameter to loaded tire diameter is what matters. If that ratio is smaller (i.e. smaller brake disc or larger tire) then greater pressure is required for comparable braking action.

Is it really the full disc diameter that should be considered or perhaps something like the radius at the effective center of the brake pads? Radius of center of caliper piston(s)?

[skywagon8a]

Not arguing, but expanding on this a little bit; the ratio of brake disc diameter to loaded tire diameter is what matters. If that ratio is smaller (i.e. smaller brake disc or larger tire) then greater pressure is required for comparable braking action.

Is it really the full disc diameter that should be considered or perhaps something like the radius at the effective center of the brake pads? Radius of center of caliper piston(s)?

Both valid answers. In this case a single puck brake on a 5" wheel has inadequate brake clamping capabilities. IF he had a 6" wheel, he could just replace the single puck brake with a double puck brake thereby doubling his braking capabilities. There are no double puck brakes available for a 5" wheel. Therefor in order to double his brake capabilities it is necessary to add a second single puck brake. Due to the confined space available, it is easier to just install another second complete disc assembly on the opposite side of the wheel.

Dan's master cylinders and the brake cylinders are pressure/volume compatible.

The dual system has the power to lock a wheel enough to skid the tire.

[cubdriver2]

Maybe Douten will chime in? His seems to work ok

Glenn

[skywagon8a]

Maybe Douten will chime in? His seems to work ok

Glenn

Does he have the same nose gear and strut arrangement? If different, that's all it takes for ease of steering control. Nose gear geometry in amphibs has a history. They each have their own issues big or small. They all require a good braking system.

[Dan Gervae]

The guy I’ve been talking to in Florida with these floats changed out the carbon fiber front gear to a 7075 aluminum bar of same dimensions… he reports much better performance and less twisting when casters are 90 degrees…I may do same

[Dan Gervae]

anyways…all troubles aside I thought I’d show you how I do my rudder cable retract…after wearing through many of the bent stainless tubes where the cable entered the cockpit…I always make a simple pulley setup. Works awesome

[cubdriver2]

anyways…all troubles aside I thought I’d show you how I do my rudder cable retract…after wearing through many of the bent stainless tubes where the cable entered the cockpit…I always make a simple pulley setup. Works awesome

Pete beat you to it and faired it

Glenn

[skywagon8a]

Now bend up a U clip to place over the pulley to prevent the cable from falling off. Your right, it is slick, easy to operate.

[Douten]

Been busy Glenn and was going to post, Baumann's have the grove set up for brakes that work well will not really lock up the brakes when landing I just have the stock scott brakes and don't feel any need for more braking (land slow and plan ahead) I have parking brakes for starts on pavement or around other planes that really helps with no electrics. wet grass takes a little to keep them dry enough to be effective.

[Dan Gervae]

Douten, is your front gear a little twisty when casters are at 90 degrees? Or Is the Baumann front gear pretty robust? My brakes when on wheel were pretty weak …standard Scott with single puck Cleveland…these groves with the north rivers have noticeably more braking…I was just concerned I need more braking on the amphibs.

[TcraftF21]

I have Baumann 1500A on the Tcraft and the brakes are a little weak but fine unless you would need to lock them up landing. I have Cleveland master cylinders on the F21 that takes a bit off forse to get the nose wheels straight at start up but otherwise no problems at all.

Jim

[skywagon8a]

Dan, These are the best pictures I've seen of your nose gear. The section ahead of the strut attach location appears to be a thin flat piece of carbon fiber layup. This may be weak in torsion. After you get your brakes squared away, turn the nose wheels 90 degrees. Have someone take a close up picture while holding the brakes running the engine to full power. Does the flat section twist so that the nose fork pivot bolt changes it's angle from the vertical position? If so, that means a greater force will be required to straighten the nose wheel due to the fact that it also has to do some lifting in order to turn. This lifting has to counteract the additional down loads created by the engine power. Think, High thrust line pivoting on the locked brakes reacting against the distance to the nose wheel. You may find a need to add a stiffener strap.

Attachment 59593 Attachment 60753

All of the amphibs of which I have been involved, including flying boats with nose wheels, have castering nose wheels. In all cases they require strong brakes and power to correct for a fully turned wheel. When the pivot of that turned wheel is not vertical there is an added amount of weight which must be lifted in order to turn that wheel.

I hope I explained this clearly enough.

[Dan Gervae]

Test flight went perfect guys…thanks so much for all your help. It gets off the water good…it’s a little different than my Tcraft, so after a little practice and knowing the sweet spot be
tter, it’s going to be fabulous. The gear handled my rough 2000’ asphalt runway well and you can’t tell the difference in flight (barely) between gear and floats. Feeling very blessed. Thank you all so much again for the help.


Pete, you never failed to reply with helpful advice….A special Thanks to you! First flights are nerve wracking. Lol time for a cold one.

[Douten]

Dan t-craft is right about the nose wheel when 90 degree the arm has a little play but seems strong enough. glad you have it flying.

[Dan Gervae]

Pirep after some more hours on the Meads….the shocks are amazing, they handle my rough asphalt strip very well. Gear actuation works well….one wheel at a time…so it’s about 27 second cycle time. The gear indicators can be easily seen from the cockpit, plus there are leds that light up on the panel. Floats handle on the water very well and even though I’m missing my spray rails…the fluted bottoms negate the need for them…prop doesn’t get spray. They have around 10” of freeboard with me 220lbs and 18 gals of gas….noses seemed at first to ride a little low, but I’ve found they pop right up with power application. I’m still learning the quickest technique to the sweet spot…seems to have a second rise after which you relax stick and it goes right onto step. They have a nice large sweet spot with no bad behavior. I only timed one takeoff with 18 gallons and me on 85 degree day and I got 14 seconds….I did push over too hard to force onto step so I’m sure with experience in this plane, I’ll lower that time. I think anyone flying one of these light amphibs says a little more floatation would be nice, but so far I’ve seen no bad behaviors in downwind water taxi turns in 10kts wind so they seem adequate. I list almost no cruise speed. I’m very happy with the setup…I got in on the cheap with an excellent little set of amphibs.

[skywagon8a]

I’m still learning the quickest technique to the sweet spot…seems to have a second rise after which you relax stick and it goes right onto step.

Learn when that second rise is just thinking about starting. There is a slight seat of the pants feeling just at this point. At that point, relax the back pressure allowing the nose to slip up onto the step by it self. Don't push it over, let it go by itself. Any portion of that second rise is a small piece of drag and extra time. You'll get it, enjoy.

[BC12D-4-85]

Why do some floats have that 2nd rise? I've noted it mainly under low power or otherwise when heavy

Gary

[skywagon8a]

Why do some floats have that 2nd rise? I've noted it mainly under low power or otherwise when heavy

Gary

You're too used to it and compensate automatically. I think I've found it on any seaplane I've flown, some more pronounced than others though.

[Dan Gervae]

My Tcraft on Baumann’s has one rise solo and a less pronounced second rise when loaded….I notice higher oil temps on both my Tcraft and my Cub when on floats….I think a more pronounced lip on bottom cowl might help? Not too sure

[BC12D-4-85]

From your pics I'd double what lip dimension you currently have and test. Tape on the added and then mount if it works. Simple polycarbonate is flexible for cutting/forming a lip

Gary

[skywagon8a]

Higher oil temps aren't bad, as long as they don't exceed the limits.