terrain/cloud sighting scope

[Bryan Wood]

Does anybody have experience with the small tube type scopes that you can look thru to determine if you will clear clouds or terrain? First, do they work well, and if so what are they called and where do I find one. My wife and I seem to start debating whether or not we will clear clouds about 50 miles out and I'd like to buy her one. So far I've had no luck looking thru on inline pilot suppliers.

Thanks,

[Hostage46]

Hmmm never heard of that kind of gadget. I was taught to pick a reference point on the windscreen and if it moves up, you your going to hit it, if it moves down, you're good to go.

Sounds a bit TLAR

[RVadmirer]

This is a source for a David White model, others make them. They are used for grade checking.

http://www.whitecapdirect.com/store/...oduct-v2.0.jsp



http://www.lascolaser.com/show_produ...=Hand%20Levels

This source has other brands and prices. The suggestion to use a spot on the canopy should work though, that theory is what we use in boating to see if we're on a collision course with another boat, rock, buoy etc.

[mdoyle]

Johnson makes an inexpensive plastic version for $15-20.00, that's the one I've seen in Pilot catalogs, (usually for a lot more). Google "Johnson hand sight level" and you will find it several places. It's primarily used in the construction/excavating industry to quickly compare elevations. I have the David White version and it is a nice piece of equipment. It is very difficult to hold it perfectly level when standing on solid ground, so I'm not sure how usefull it would be in an airplane, I've never tried it.

Sporty's has this one:

http://sportys.com/acb/showdetl.cfm?...ID=1621&DID=19

[gmcjetpilot]

I think its one of those Sporty Pilot shop wastes of money, but it could be a good tool to learn how to sight cloud heights, but there are easier ways to estimate with out a gadget. I have had many students that have shown up with gadgets and all kind of things. I don't laugh but eventually they learn they don't need it and its more cumbersome than helpful. However it does have a use in helping understand the sight or aim point principle which is SO basic is all phases of flying, especially landing and flight maneuvers. This basic principle applies to determine if a distant object, plane, mountain top, cloud top is higher than your altitude.

The scoop is just a telescope with a level. So if you learn what your level sight point is in the wind screen of your RV, in level cruise, you can kind of estimate it with out any fancy tools or gadgets. All planes I kind of developed a sight line or bug spot that makes an aim or reference point. So many inches below the spot is good.

It's like landing, picking an aim point thru the windscreen. The same aim point can be used to reference the cloud top (as you sit normally). Mark that spot on the windscreen mentally, with a piece of tape or grease pencil so it sits on or a little above the top of the cloud, which we assume for discussion is in front of you and are flying towards.

IF AS YOU FLY CLOSER THE AIM SPOT MOVES DOWN INTO THE CLOUD YOU WILL FLY THRU IT, SPOT RISES or STAYS ABOVE THE CLOUD YOU FLY OVER. You are looking for a trend. Also assumptions are you are flying level and the cloud layer or top is not slopping up or building.

Remember one caveat is cloud tops cab BUILD rapidly in front of your eyes, so be careful topping CB's (in the mature or building stage). Also there can be turbulence and down drafts around the tops of CB's. I personally will avoid flying over CB's if not by about 1000-2000 feet.

If its a stratus layer than that is different. However stratus can slope up when its sitting on top of a frontal system and you may find it may out climb you. It's very tricky to tell if an under-cast is flat (level to your altitude) or rising, especially when its an extensive layer with no real horizon. A fully loaded RV at +10,000 feet may not be able to climb out fast enough and you may end up IMC if not careful. Unless you are IFR qualified, current and equip, be careful flying over building or sloping cloud tops. Rule of thumb is planning clearing CB's by 2000 feet and stratus by 1000 ft. If you can't fly higher, around, under than turn around. That is conservative but it can also be fatal for VFR pilots to fly IMC. You should be able to estimate cloud height from weather reports and eye ball. Part of the private pilot syllabus is estimation of distance from clouds. It just takes practice. If there is a doubt than consider plan B.

Speaking of woman co-pilots, wife's, girlfriends in planes and their voicing their opinion, I find them very useful and you should listen, chance is they may be right. The more you teach them and the more hours and experience they get, the better it gets. Being conservative is NOT a bad thing. There is no shame or lack of macho in NOT flying over a cloud. Never disregard your co-pilot out of hand. However if you have a reason to continue (like the aim point is rising) or have a plan-B (fly closer and decide in 10 minutes) and can explain that, the co-pilot is satisfied, that is called communication and good decision making. You as PIC does have veto power of course, but you better be sure you're right. So if this argument, "are we going to make it over the cloud", is an issue, than the scope may be a good tool in teaching your co-pilot how the bug speck aim point works. Once the co-pilot understands that, than you can retire the scope.

[n5lp]

Personally, I like to keep the cockpit gadgets to a minimum, but I have noticed that Richard Collins of "Flying Magazine" has often mentioned using this. He has a lot more experience than me.

[mannanj]

Somewhere, back in the cobwebs of my memory I remember being told that IF you could see the horizon; (operative word "IF") whatever was above the horizon was above YOU---whatever was below the horizon was below YOU.

When on active duty with the USAF, I was a photographer on C-130 aircraft recovering film canisters that had been de-orbited from the early spy satellites. The parachute would deploy below 50,000ft. We were orbiting around 28,000ft. We found the parachute by radio direction finding then closed in. The pilots would always match decent rate to the parachute by keeping the parachute on the horizon as we made our teardrop pattern to catch the parachute with hooks and rope out the back of the plane.

This doesn't take into account what George mentioned about sloping cloud decks, etc. Just a good rule of thumb when conditions are right.

[jdmunzell]

A simple glass of water, soda, etc.. in a clear cup or glass is also a cheap leveling device. You simply site thru the glass across the level top of the liquid. The closer you are to the cloud, the more acurate it is. The further away it is, the more Mother Earths' curvature comes into play. Works at 5000 ft. or 35,000 ft.