I'm looking at amphib floats. One opinion I've heard is that a manual-only hydraulic system is simple, lighter, reliable, and low maintenance. I like all of that, although it also seems like a lot of work if I was busy in a tight area. Interested in any opinions on this.

Aircraft is a Scout with 2100As...

Try pumping 86 times (twice) with your head up! Flying the aircraft is more important to me than pumping! I like the sound of the little motor too.

I would install a hydraulic pressure gauge to monitor pressure of the hand pump (without the power pack). The gear does have down and up locks, but I would hate to have any creep...the electric unit provides constant even pressure.

The pump also helps with the fwd CG, that most amphib have.

Keep the hand pump for a backup.

I quizzed Alton Buschard about this when he was certificating the PK 2250 amphib floats. I asked him why he didn't make a manual retraction system an option at least. He responded that under the current certification standards, the FAA would not certify amphibious floats with a manual only system. Sounds goofy to me, since you always have to have a manual retraction system as a back up to the electric system anyway....

I flew a Beaver with Bristol Aero amphibious floats for several years, and that float system had a manual only retraction/extension system. Worked fine and was very simple and reliable. I can't recall the number of pump strokes to extend or retract the gear, but it wasn't bad, maybe thirty??? The little tiny manual pumps they install as back ups take forever to extend/retract, but a slightly larger pump could move a lot more volume.

But, it is the FAA, after all.

MTV

If I had a longer handle and a bigger volume pump, I could get them down in half the time! My little back up pump is very low volume but can develop a lot of psi if needed.

I personally love my little hydraulic power pack! The 9 lights on the dash ( 4 blue water, 4 green land, 1 red for pump operations ) and the audible gear position STC are great too! Below 80mph it tells where the gear is (until you clear it). Wip engineered it well and I wouldn't go back to a manual pump.

Manual pumping amphib gear, is like manual locking hubs on 4x4s, not seen in modern installs to much!

One set I'm looking at, the guy said 26 pumps. I could probably live with that, but I think 86 pumps would be over the limit for me!

skyjeep wrote:One set I'm looking at, the guy said 26 pumps. I could probably live with that, but I think 86 pumps would be over the limit for me!

I might of exaggerated the number 86, but its close to that number with the tinny backup pump provided. But, remember hydraulics are like electricity...volume ( I.e. amps) decreases pressure ( volts ). The more volume for each stroke the less pressure. Total force can not change ( watts ). Bringing the gear up requires a little more pressure than dropping it.

Who is on your short list for the floats?

Interesting note:

Fluidyne C3000A install has the option of using any AN6201-1 manual hydraulic pump with a displacement of 1.26 to 1.6 cu inches per cycle and a 30-40 cubic inch reservoir. Drawing 11F1671 latest revision.

Or use the full electrical powerpak with a high pressure limit switch. This unit is also used on the floats too but, with a lighter pressure limit switch. There is a plackard that calls out the switch change when going to floats/skis. Hand pump would be used for backup only.

And, that hydraulic power pack weighs 18 pounds....on a small airplane, that's a lot just to save a little manual pumping, but whatever winds your watch.

MTV

We need that 18lbs anyway or ballast.

I'd rather use 18 lbs for useful load if I can, since we're talking about amphibs...

Who's on the short list? 2705s. If money was no object I would buy Aerocets and a 185 to go with them. But for a 180 for personal use, it's old metal floats. I love my 2870s but never get to use them any more since I'm now land-locked. For amphibs, most are just to heavy to be practical on a 180. I'm looking for the lightest setup I can get. I have Wing-X, and with that it should make a good 2-3 person amphib. Maybe 4 with minimum fuel and another non-overweight couple, if I can keep it light. I would really like to have ability for occasional 4-place joy flight, we've had a lot of fun with that on straight floats when I still lived on a lake in the NW.

I'm also interested in a hydraulic setup that I could also use for skis, after reading aktahoe1's posts on playing in the Sierras

You probably could get an approval using a hand pump to save weight. If the specs are clean and reliable. I would consider it a major alteration but, that should not matter if done well. There is plenty of approved data that shows a singular hydraulic hand pump is safe and reliable.

The hydraulic unit I have is completly integrated for both skis and floats with landing gear position lights and gear position warnings. I fly solo 99.99 % of the time so 18 lbs is negligible and the convenience is outstanding during approaches and departures.

I got the 2705 installation drawings from Edo. The manual system is the basic system, and there is a note that says "The basic hydraulic system consists of items 1 through 53. Available as added optional equipment is an engine driven pump kit consisting of items 54 through 67."

So it looks like there is no need to get an approval, it is covered already.

And, if a pump doesn't come with the floats, be advised that Parker still makes most of those pumps.

MTV

If you have drawings, do a paper install with W/B and CG calculations. See where you are and how to load the seaplane. I agree, loading seaplanes require every bit of attention to weight.

You are doing the right thing, keep her light, I my opinion. Thank you for the information.

Items to look at:

#1. Check insurance. Seaplane amphibians are expensive, high risk, and little market saturation. Therefore rates are high, sometimes very high.

#2. Do a paper install and check W/B and CG. Don't trust advertised numbers. See if you can live with the weight. Are we going to be legal (generally) for most flights? I have to have half tanks solo!

#3. If #1 and #2 work, you will have one of the coolest machines mankind has ever created! You will never look back!

Hope you get the set of floats!

Thanks guys for the tips. Looking back, 8GCBC you mentioned a AN6201-1 pump for use with skis. That is in fact the pump that is specified by Edo for the 2705 installation.

On the paper W/B, I do want to run that for CG--I have run it for weight and I know it will be a 2-3 person amphib with full main tanks. Should work fine for my wife and me. I would guess CG is unlikely to be an issue loaded, more likely when solo. I have the Edo guide to floats on the way and I believe it has W/B info including CG.

As for insurance--yes another important consideration on amphibs. I'm checking but already resigned to the fact that I may need to just go with liability and not in motion if it's too much. And I'm sure I can train my wife to whack me upside the head if I'm ever about to land with the gear in the wrong position, it works for things like mags off/keys out

Back to the original question I had--I haven't heard any downsides to manual-only other than convenience. And with the 2705 hydraulic system, I can go with a manual pump now and add an engine-driven pump in the future if I decide I prefer the convenience over the weight.

Are there up and down locks on EDO 2705 amphibians? I read some brands of amphibs require pressure to keep gear up, this could be dangerous if there is any actuator creep. An automatic pump may help keep gear in the correct position easier than manual.

I like the idea of saving weight, but system pressure may need to monitored to keep gear in correct position. My red hydraulic motor light cycles every 30-60 minutes approximately for about a 1/2 second, adding correct pressure and confirming everything is well. I know the gear is locked but, also enjoy knowing there is system pressure to back it up. Slightly paranoid about the gear as I am new to this stuff.

Just me thinking out loud! I am a low time SES guy with opinions! Please keep us informed, via the thread of your ideas and progress.

Not sure about gear locks, I'll check when I get the manual.

Here are a few pics of the hydraulic setup, hard to see without disassembly. But does any of this look identifiable? For the Edo STC, the hand pump part number I need is AN6201-1. The Hydraulic Pak Assembly is 35593. The Cockpit Control Unit is 35644.

Hand Pump

Gear Indicators

Reservoir

J. J. Frey at seaplanes.org has helped me with questions. He is a standup guy and knows EDO better than most. He wrote the book!

* The pump looks low displacement, I.e. back only? Normal ops use powerpak?

* The reservoir may be hard to check level and fill? Wip has a sight glass, very easy to see and service.

*. Try flying and moving the gear with the small hand hydraulic pump. See if it works for you.

Note: the hand pump in the picture should be allowed with Fluidyne hydraulic skis ( but check the STC before purchase to be sure ). It's on my drawings for Fluidyne C3000A STC.