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Float planes?

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Float planes?

Posted: Fri Feb 17, 2012 8:40 pm
by David M Parrish
I've got a question (or two) for those water-walkers out there.
What's a good book on flying float planes? How much of a
performance hit do you take switching from conventional gear to
floats? (If anyone have some numbers specific to the Rebel or
Super Rebel, that'd be great.) How much float do you need for a
particular gross weight? How rigid are those numbers?

Thanks,
David Parrish

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Float planes?

Posted: Fri Feb 17, 2012 8:40 pm
by Bob Patterson
Hi David !

Lots of good books - look for something by Jay Frey (Pres.
of EDO, and LONG time float pilot), for starters ...

With the Rebel, going to 1800 straight floats will cost about
5 mph on cruise - amphibs will take about 10 mph...

The Rebel is rated at 1730 gross on floats, so the 1800's
are ideal. You <can> go with 1500's, which are a bit lighter,
but they sit VERY low in the water, and you'll have a longer takeoff
run, and possible problems in large waves ( submarine, anyone ;-) )
Generally, you're better off with a bit too much float, rather than
too little ... the performance will be proportionately better on
larger floats.

.....bobp
-------------------------------orig.---------------------------------
At 08:02 AM 2/15/01 -0500, you wrote:
I've got a question (or two) for those water-walkers out there.
What's a good book on flying float planes? How much of a
performance hit do you take switching from conventional gear to
floats? (If anyone have some numbers specific to the Rebel or
Super Rebel, that'd be great.) How much float do you need for a
particular gross weight? How rigid are those numbers?

Thanks,
David Parrish

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Float planes?

Posted: Fri Feb 17, 2012 8:40 pm
by Tim Saxton
I found "Flying a Floatplane" by Marin Faure to be a good introduction to
floatplane flight techniques, maintenance, and safety. The book says that
the combined buoyancy of both floats must be 180% of the airplane's gross
weight. Furthermore each individual float must have at least 4 watertight
compartments and must continue to support the plane with any two
compartments flooded.

I think it was on this list that someone said "a floatplane can never have
enough power or enough floats". This is probably why there is so much
interest in the M14P engine for the SR. I believe the displacement for the
planned Murphy SR floats is 3600 lbs each so at total gross weight for the
SR-3500 (3675 lbs) this puts total displacement at about 200%, and for the
SR-2500 (3150 lbs) the displacement would be 228%. So with the new engine
and floats the SR should be an excellent performer.

Tim Saxton
SR060

-----Original Message-----
From: David M Parrish [mailto:dmp@radbsd.mcg.edu]
Sent: Thursday, February 15, 2001 5:02 AM
To: Murphy Rebel Builders List
Subject: Float planes?


I've got a question (or two) for those water-walkers out there.
What's a good book on flying float planes? How much of a
performance hit do you take switching from conventional gear to
floats? (If anyone have some numbers specific to the Rebel or
Super Rebel, that'd be great.) How much float do you need for a
particular gross weight? How rigid are those numbers?

Thanks,
David Parrish

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Float planes?

Posted: Fri Feb 17, 2012 8:40 pm
by David M Parrish
On 15 Feb 2001, at 19:27, Bob Patterson wrote:
Hi David !

Lots of good books - look for something by Jay Frey (Pres. of
EDO, and LONG time float pilot), for starters ...
Thanks.
With the Rebel, going to 1800 straight floats will cost about
5 mph on cruise - amphibs will take about 10 mph...
I'd think a Super Rebel should have close to the same loss.

Are amphibs really that much more draggy? I'm surprised someone
hasn't come up with some sort of door mechanism like most other
RG aircraft.
The Rebel is rated at 1730 gross on floats, so the 1800's are
ideal. You <can> go with 1500's, which are a bit lighter, but they sit
VERY low in the water, and you'll have a longer takeoff run, and
Are floats rated per float or per pair? If each, then having twice the
gross weight in floatation is the norm?

---
David Parrish

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Float planes?

Posted: Fri Feb 17, 2012 8:46 pm
by Bob Patterson
I suspect that the Super Rebel will have a larger loss of cruise,
since drag squares with speed, and the SR cruises a good 25 mph
faster than the Rebel. Also, the SR floats will have a LOT more
surface area ! I would expect the SR would probably lose about
20 mph or more on amphibs.

Amphibs are complex enough now that insurance companies
expect an 80 % (!!) loss ratio (odds are 4:1 that you'll dunk it
sometime !!). There's more involved than just main gear doors, too -
there's a lot of drag from the nosewheels & the nosewheel support
structure, and the extra weight of the gear & mechanism.

The floatation rating (1800 lb) is the buoyancy of EACH
float - a good margin is needed for safety, in case of a leaky
compartment (or 2 ;-) ).

.....bobp

-------------------------------orig.-------------------------------------
At 08:02 AM 2/16/01 -0500, you wrote:
On 15 Feb 2001, at 19:27, Bob Patterson wrote:
Hi David !

Lots of good books - look for something by Jay Frey (Pres. of
EDO, and LONG time float pilot), for starters ...
Thanks.
With the Rebel, going to 1800 straight floats will cost about
5 mph on cruise - amphibs will take about 10 mph...
I'd think a Super Rebel should have close to the same loss.

Are amphibs really that much more draggy? I'm surprised someone
hasn't come up with some sort of door mechanism like most other
RG aircraft.
The Rebel is rated at 1730 gross on floats, so the 1800's are
ideal. You <can> go with 1500's, which are a bit lighter, but they sit
VERY low in the water, and you'll have a longer takeoff run, and
Are floats rated per float or per pair? If each, then having twice the
gross weight in floatation is the norm?

---
David Parrish

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Float planes?

Posted: Fri Feb 17, 2012 8:46 pm
by Warren T. Montgomery
-----Original Message-----
From: David M Parrish [mailto:dmp@radbsd.mcg.edu]
Subject: Float planes?
What's a good book on flying float planes?
Dave,

Fred Potts published on the WEB (800th site) a long time ago a book
called F. E. Potts' Guide to Bush Flying, available for download at
<http://www.fepco.com/BF_Table_of_Conten ... nformation>
Also available for direct purchase. I don't think there is anything
specific to floats, however there is useful info on Bush and ski flying
(although I've done neither) maybe someone with some experience can
review and comment.
Fred flew for many years out of Alaska and is now retired to somewhere
in the South. He's using the WEB to pass on his lives experiences in the
bush, free to all. Check out the grizzly his wife bagged with a six
shooter back in 1969.
I'll certainly be packing a 12 ga. with slugs,
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
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Float planes?

Posted: Fri Feb 17, 2012 8:46 pm
by Bob Patterson
Thanks for reminding me of this book !! I found it a year or
2 ago, and never got back to read it. This really IS an interesting
and educational read !!!

You might have a problem with that 12 guage - what with our
new, wonderful gun laws !! :-( You'll have to sign your life away,
and pay $60 - for now .... more later ! What an ENORMOUS waste of
tax dollars, just to gain a few city-slicker votes !! Let's start
a campaign to get rid of Allan Rock ! He's dangerous !!!

.....bobp

----------------------------orig.-----------------------------------------
At 09:32 AM 2/18/01 +0400, you wrote:
-----Original Message-----
From: David M Parrish [mailto:dmp@radbsd.mcg.edu]
Subject: Float planes?
What's a good book on flying float planes?
Dave,

Fred Potts published on the WEB (800th site) a long time ago a book
called F. E. Potts' Guide to Bush Flying, available for download at
<http://www.fepco.com/BF_Table_of_Conten ... nformation>
Also available for direct purchase. I don't think there is anything
specific to floats, however there is useful info on Bush and ski flying
(although I've done neither) maybe someone with some experience can
review and comment.
Fred flew for many years out of Alaska and is now retired to somewhere
in the South. He's using the WEB to pass on his lives experiences in the
bush, free to all. Check out the grizzly his wife bagged with a six
shooter back in 1969.
I'll certainly be packing a 12 ga. with slugs,
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
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Float planes?

Posted: Fri Feb 17, 2012 8:46 pm
by Drew and Jan
I'm behind you 100% on that one Bob. I'm neither a hunter or a gun owner
but I think history will show our new gun law to be one of the most
expensive and least effective peices of legislation ever conceived.
Drew

At 09:37 PM 2/18/01 -0500, you wrote:
You might have a problem with that 12 guage - what with our
new, wonderful gun laws !! :-( You'll have to sign your life away,
and pay $60 - for now .... more later ! What an ENORMOUS waste of
tax dollars, just to gain a few city-slicker votes !! Let's start
a campaign to get rid of Allan Rock ! He's dangerous !!!

.....bobp

----------------------------orig.-----------------------------------------
At 09:32 AM 2/18/01 +0400, you wrote:
-----Original Message-----
From: David M Parrish [mailto:dmp@radbsd.mcg.edu]
Subject: Float planes?
What's a good book on flying float planes?
Dave,

Fred Potts published on the WEB (800th site) a long time ago a book
called F. E. Potts' Guide to Bush Flying, available for download at
<http://www.fepco.com/BF_Table_of_Conten ... nformation>
Also available for direct purchase. I don't think there is anything
specific to floats, however there is useful info on Bush and ski flying
(although I've done neither) maybe someone with some experience can
review and comment.
Fred flew for many years out of Alaska and is now retired to somewhere
in the South. He's using the WEB to pass on his lives experiences in the
bush, free to all. Check out the grizzly his wife bagged with a six
shooter back in 1969.
I'll certainly be packing a 12 ga. with slugs,
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
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