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12-13-2010, 03:29 PM
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Join Date: Dec 2008
Location: Fuquay Varina, NC
Posts: 75
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Water Landing, Ditching, Tip-Up, On or Off
Hey folks,
I was reading this thread regarding ditching:
http://www.vansairforce.com/communit...ad.php?t=12771
and there did not seem to be a clear consensus about the best course of action. The scenario being, a controlled, engine out landing over water with a TIP-UP, what is the preferred status of the canopy, options include:
A: Avoid an engine out landing over water (yes, that sounds like the best answer to me)
B: Leave the canopy fully closed and latched until after she flips on touchdown (seems like this retains the most structural integrity)
C: Partially unlock the canopy, ball and twist latch before the touchdown and manually hold closed (I know the canopy will raise up significantly if not latched, which is another story  )
D: Jettison the thing if you have time, quick canopy release, lift assist cylinders and latches)
Reason for asking, let's assume your flying at 500 feet over open water, too far from land to glide to a soft beach landing.
Thx
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12-13-2010, 03:40 PM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Since no one has ditched a tip-up that I know of, this is all conjecture.
I would open the canopy but not jettison it. It will float open about two or three inches. This I know from experience as I left open as a flight test during my first Phase 1. (If you do this test, make sure there is nothing in your plane that can be sucked out, because it will.)
My thinking is that when you touch on the water, the plane will pitch forward violently and will probably come to a rest nose down. (This is what happened to a friend when he ditched his Cherokee.)
With luck, the canopy will rip off and if not, it will simply be a matter of pushing it out of your way to get out after releasing your belts.
At least that's what I put in my POH and I sure hope I never have the opportunity to find out if it is correct or not.
I see no reason to jettison the canopy as that could damage the flight controls and with the wind in your face, you may not be able to see to land after that blast rips your glasses and headsets off.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
Last edited by N941WR : 12-13-2010 at 03:42 PM.
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12-13-2010, 03:55 PM
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Join Date: Nov 2005
Location: KRTS
Posts: 1,798
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I didn't know you could jettison a tip up, but I wouldn't based on the high likelyhood of ripping off your empennage.
A buddy of mine ditched a C-152 of Hawaii, and it stayed upright FWIW. He and his wife got out, and he was even able to swim back in and save his favorite running shoes. The air in the tail kept it bouyant for quite a while.
For a sliding canopy, I would def leave it closed. The likely hood that it slams shut and jams on touch down being my main concern. Either way, I'd keep a framing hammer secured and available in the cockpit if you're planning a long over water flight. I think that's about the only real tool useful for breaking your way through if need be.
__________________
Next?, TBD
IAR-823, SOLD
RV-8, SOLD
RV-7, SOLD
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12-13-2010, 07:52 PM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Quote:
Originally Posted by Sig600
I didn't know you could jettison a tip up
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Only if the jettison handle is installed and the slots are cut in the skin and you think you can brake through the fiberglass that is supposed to cover the hole.
Quote:
Originally Posted by Sig600
but I wouldn't based on the high likelyhood of ripping off your empennage.
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Maybe, but as I said, no one has jettisoned a tip-up that I know of.
Quote:
Originally Posted by Sig600
A buddy of mine ditched a C-152 of Hawaii, and it stayed upright FWIW. He and his wife got out, and he was even able to swim back in and save his favorite running shoes. The air in the tail kept it bouyant for quite a while.
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They were lucky. The RV's tail aren't so boyant and I think you might be lucky if the thing floats for 10 minutes.
Quote:
Originally Posted by Sig600
For a sliding canopy, I would def leave it closed. The likely hood that it slams shut and jams on touch down being my main concern.
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Exactly my concern with the slider but then, chances are you aren't going to be fighting to get the thing open, which is difficult to do in flight, why getting ready to ditch.
Quote:
Originally Posted by Sig600
Either way, I'd keep a framing hammer secured and available in the cockpit if you're planning a long over water flight. I think that's about the only real tool useful for breaking your way through if need be.
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Lots of threads on this subject. Try doing a search and see what comes up.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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12-13-2010, 08:21 PM
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Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,351
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I know this sounds sort of a wild idea, but as I was running thru that scenario I thought how about getting the plane really slow and close to the water and then try to dip one of the wing tip in the water to cause the plane sort of cartwheel. Do you think it has a better chance to stay upright?
I am thinking as soon as the wheels touch the water, I flipped over and by upside down. But if I may have a better chance if I can drop one wing in the water to cause it to cartwheel?
My other thought was that to bring it really low and then try a really nose up attitude to the point that I can hit the tail first, preferably hard, so again trying to prevent an upside down situation.
If I can stay right side up, then the canopy is less of an issue being in an aquarium and wanting to deal with the canopy
Thoughts on that?
__________________
Mehrdad
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - Flying
Dues paid
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12-13-2010, 09:23 PM
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Join Date: Oct 2008
Location: Arlington, WA
Posts: 799
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As long as we're talking wild ideas...
My concern would be that my plane would try to become a lawn dart on the bottom of the ocean. It's much easier to egress if you're only one foot under water instead of two hundred feet and accellerating! So I did a little math...
My RV-7 has a gross weight of 1800#.
A cubic foot (ft3) of water weighs 62.4#
1800# divided by 62.4# = 28 ft3
By displacing 28ft3 of water, my RV7 would be bouyant!
28 ft3 is an area 3' x 3' x 3' (ok, I'm rounding off a little here).
USComposites.com sells a 2# expanding foam - two pounds per ft3 - which would add about 60# to the weight of your RV7.
So if we could put 28 ft3 of foam into various nooks and crannies, our RV's could float and make egress after ditching much simpler.
Problem solved!
__________________
_______________________________
Scott "Grumpy" Stewart
RV-7 N957RV (First Flight on Dec 18, 2009 )
RV-14 N144P (Empennage complete, wings almost complete, fuselage almost complete)
#866 on the Van's RV-7 hobbs
#6563 on Van's generic hobbs
Arlington, WA
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12-13-2010, 09:29 PM
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Join Date: Oct 2008
Location: Arlington, WA
Posts: 799
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Or an alternate idea...
Quote:
Originally Posted by DakotaHawk
USComposites.com sells a 2# expanding foam - two pounds per ft3 - which would add about 60# to the weight of your RV7.
So if we could put 28 ft3 of foam into various nooks and crannies, our RV's could float and make egress after ditching much simpler.
Problem solved!
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... would be to build a lightweight aluminum "airspace tank" in each wing on outboard ribs. Build it like a fuel tank to be airtight with proseal, etc. The airspace would not weigh any extra, and you get the bouyancy without the weight of foam.
I would determine how the plane would settle in the water and then create a tiny vent on the "bottom" of the airspace tank - just enough to equalize air pressure as altitude changes. With the vent on the "bottom" of the airspace tank, no air would escape when you have to ditch.
Just another thought...
__________________
_______________________________
Scott "Grumpy" Stewart
RV-7 N957RV (First Flight on Dec 18, 2009 )
RV-14 N144P (Empennage complete, wings almost complete, fuselage almost complete)
#866 on the Van's RV-7 hobbs
#6563 on Van's generic hobbs
Arlington, WA
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12-13-2010, 10:07 PM
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Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,351
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how about airbags
Scott,
I like your thinking, alternatively if one could only create small airbags that would fit inside the fuse/tail or wing and fill it with air. Much like when we used air bag in our white water kayak to keep it from filling up with water. It does not need to be super strong, only to stay inflated.
Only thing is that you got to watch out as you climb up or descend, perhaps a pressure valve would be nice 
__________________
Mehrdad
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - Flying
Dues paid
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12-13-2010, 11:34 PM
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Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
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As long as we're talking fancy ideas, how about a can of expanding foam like that used to fill joints in windows? It expands and hardens quite rapidly. Could you fill a cavity fast enough on final approach that it would help with buoyancy?
Or another option, one of those canned air cannisters, and a tough garbage bag. Seal the cannister in the bag, and manipulate the sprayer on top manually to fill the bag with air. Instant buoyancy.
Or buy an automatic-inflating life jacket, and leave it loose in the cockpit. Water will trigger the cannister to inflate the jacket.
One could probably even make use of an automotive airbag and sensor mechanism to fill a cavity with an inflated volume, perhaps? Triggered on impact? While you're at it, add one to the glareshield so you don't carve your forehead open on impact like a lot of people do.
Oh, and FWIW, my water ditching procedure in the tip-up will be to unlatch everything on the canopy, and expect it to either depart on impact, or be ready to open after impact. I was never convinced that the canopy could be jettisoned in flight with the mechanism used for the hinge, even with the leaky slots in the forward fuselage.
__________________
Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
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12-14-2010, 10:26 AM
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Join Date: Nov 2005
Location: KRTS
Posts: 1,798
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I like Scotts thinking.
My plan is to just put the tops back on my empty beer bottles. If I have to ditch, there will be more than enough bouyancy to hold my plane up.
Quote:
Originally Posted by N941WR
Lots of threads on this subject. Try doing a search and see what comes up.
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Read those threads, which is why I figure a big framing or claw hammer is the only sure fire means of a quick breakout.
__________________
Next?, TBD
IAR-823, SOLD
RV-8, SOLD
RV-7, SOLD
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