The International Cessna^® 170 Association

That was an ugly one...
Magnetic anomaly detection using aircraft predates World War 2 where it was used to detect submarines. It was used back in the late 1930s by oil companies to search for minerals and oil.
MAD has been used by Navy in P-3 for decades.
Here's a prettier DC3 using it:

On the Dizzy Three above, does it always fly with the gear down with those skis on it?

blueldr wrote:On the Dizzy Three above, does it always fly with the gear down with those skis on it?

I don't know about all DC-3s but the ski rig for our local ones look like the gear is always down. But they can choose to use the skis or raise the skis to land on the wheels.

pdb wrote:

blueldr wrote:On the Dizzy Three above, does it always fly with the gear down with those skis on it?

I don't know about all DC-3s but the ski rig for our local ones look like the gear is always down. But they can choose to use the skis or raise the skis to land on the wheels.

Pete, do you know the function of the airfoil at the rear of the main skis?

John, I believe the wing is used as an anti fowler so that snow does not fly up into the flaps. Wet snow will build quickly and and could damage the flaps on flap retraction. Doug

I have been under the impression that the wing on the rear of the skis was to hold the skis in a tail down attitude while in flight so that they cannot "Nose Dig" on a landing. On small airplanes, like my L-5 in Alaska, that was accomplished with the use of bungee cords and limiting cables.

blueldr wrote:I have been under the impression that the wing on the rear of the skis was to hold the skis in a tail down attitude while in flight so that they cannot "Nose Dig" on a landing. On small airplanes, like my L-5 in Alaska, that was accomplished with the use of bungee cords and limiting cables.

I thought that was what the cable was for in the front of the ski? What is that used for then? The Dizzy also has those cables.

I think BL's explanation is closer to the mark.

These skis are hydraulic which means that they can be raised or lowered in flight to allow takeoffs on snow and landings on pavement and vis versa. In the raised position, there will be some slack in the cables and I believe that the horizontal surface stabilizes the ski in flight when in the raised position. The stabilizer may also allow the ski to maintain a more neutral attitude in cruise.

When lowered, the cables will tighten and allow for the correct angle for the ski to make contact with the snow. Smaller skis use bungees to raise the ski tips up a bit so that the tails contact the snow first. I am not sure how this is managed with these big skis.

Is there some type of wheel or roller in the aft end of the ski's to keep them from grinding while operating on pavement?

johneeb wrote:Is there some type of wheel or roller in the aft end of the ski's to keep them from grinding while operating on pavement?

John.. There are none on this set though they are not uncommon. The photo is a bit deceiving because I don't think the skis are fully retracted in the photo. I believe they are only partially retracted so the ski is resting in the concrete. When fully retracted, the ski would clear the surfaces.

ok, that makes sense. This is all pretty unusual for us flatlanders.