Adding turn and bank

[flyguy]

Re: Adding turn and bank

"It actually corrects for (mostly imperceptible) interference caused to all radio signals passing through the "weather" in the ionosphere - that's it's purpose."

Actually the main purpose of WAAS is to monitor known ground positions and compare them to where the GPS says they are and then send back a corrective signal that tells your GPS "you are not really there, you are really here." If it corrects for other things that is good, but not it's main purpose.
My 129 dollar Magellan has it, WOW, and will give me the same indication on the number 2 of runway 32 within two feet for months after I put a user waypoint there.

You know, I can practice for days with a ball compass and two weeks later it is still confusing to use it under difficult conditions. My brain just has a resistance to the way it works even though I have actually sat down and designed one that reverses the direction of operation.

This has turned into an interesting thread, hadn't thought about minimum, minimum instruments to survive in accidental IFR before.
Darryl

[Dusty]

Re: Adding turn and bank

The reality, regardless of your personal beliefs, could not be more clear: weather has no effect on GPS signals.

Flyguy: Dat's wut I said! Really! Without ionosphereic disturbance, WAAS would not be needed, but it works as you described.

I've had occasion to mark several thousand GPS points on the ground, then map them and see if they're anywhere near where I thought I was at the time. When Selective Availability went away, things got MUCH better. 12-channel parallel GPS units made things much better. WAAS makes VERTICAL things much better, but really didn't have much of a noticeable affect on horizontal error (as measured at walking speeds). Point is, most of the time, most GPS is VERY good.

[taylorcraftbc65]

Re: Adding turn and bank

This topic was just too good to stay out of. I was in a 1-26 (glider), running along the ridgelines at Ka'ala Ridge, over Dillingham, Hawaii.
I was at about 5,000, running about 3,000 under the clouds in August. As I was heading towards Schofield Barracks, one of the clouds turned from white to a medium grey in an instant. As soon as that happened, my vario pinned the needle. I set the glider in a steep dive, full spoilers and dive brakes, and I was still going up at over 2,000 FPM.
TIME TO CONTROL THE SITUATION. I knew that I was going into the cloud in seconds, so I looked at the horizon, then immediately put my head in the panel. THAT way I knew what the instruments were telling me was what I had just seen. All that I worried about was my needle ball, my vario, my airspeed, my compass, and my altimiter. I knew that the mountain was to my south, and rather that try to "fight the current", I "swam" accross it, not worrying how high I was. I turned north, kept my spoilers and divebrakes deployed, stayed below VNE, and after a while the cloud that I was in turned from the now BLACK, to grey, then white, and then I poped out, rightside up, about eight or ten miles offshore and at 17,000 feet.
I just headed back toward the Dillingham area, and dropped to 10,000 feet.
Once clear of the now huge thunderhead, I flew out to the far point of the island, and played for a couple of hours while the thunderstorm moved over Honolulu. The ONLY thing that WILL kill you is panic. Sabrina

[flyguy]

Re: Adding turn and bank

Dusty, think I understand what you are saying. My view is that WAAS takes care of ANY kind of errors, be it timing, phase shift, polarization, whatever. I'm reading you as saying that atmospheric (clouds mostly?) is the main biggie for errors. Think we're on the same track now.
DC

[Dusty]

Re: Adding turn and bank

Flyguy: The biggest error is HIGH atmospheric disturbances in the ionosphere (which starts around 170,000' MSL, well above any clouds). You are more generally correct - WAAS corrects for errors.

Another consideration is that WAAS is capable of telling you when it's not capable of correcting errors, and (some) receivers are capable of telling you when you aren't getting enough information to make that determination. That can be important! On my first-ever field trip in AK with a GPS (some ancient Magellan about the size of a briefcase that ate 16 (sixteen!!) AA batteries as fast as you could stuff them in) we were working on the Hoholitna River with a boat. On about the third site, we realized the GPS was carefully thinking about the signals it was getting, then announcing that we'd arrived - at the factory, 3000 miles to the south! Took me a long time to learn to trust the things after that.....

[flyguy]

Re: Adding turn and bank

Tell you one thing for sure. That Magellan unit I have doesn't put up a lot of avoidance data or other clutter, but it sure is amazing at telling you exactly where you are, considering it was selling in a discount catalog for $129. I put an inbound runway extension waypoint about 2 miles out from our prevailing wind runway and practiced a little with it. Think I could shoot an approach safely down to 200 ft if I actually had to. Have absolutely no intentions of doing that, but it is nice to know. Maybe do it under the hood with a safety pilot sometime or another. I know a CFII that would probably get a big kick out of that. Beats the heck out of the VOR circle approach that I used to see the guys in twins doing. Have to check with a friend who flies a corporate Pilatus (sp?) in here to see what they are using now.
DC
Danny, sorry for hijacking your thread. I'm home with a cold today and just keeping myself amused and hopefully informed.

Great story Sabrina, I have about 4 hours (3 flights) in sailplanes at Holister here south of San Jose and over in Minden, NV. Great fun.

[DanBrown]

Re: Adding turn and bank

Yes Sabrina -- always keep cool and fly.
Can a protable GPS be useful as an emergency turn indicator if caught in unforcasted IMC? I think so, but am going to try it out when I can get a safety pilot or CFII to go with me. With many days using a smiple GPS as a primary nav instrument while sailing offshore under often heavy clouds and never losing signal, I have developed some confidence in their reliability. Mine can display goundspeed, altifude, rate of climb and flignt direction at the same time -- although with several seconds lag time. Howver, are they sufficient (in combination with a ball slip.skid indicator) to keep one out of trouble in heary turblance?? Getting put into unusual attitudes while under the hood and trying to recover would be an interesting test.

[Dusty]

Re: Adding turn and bank

Dan: some units have an artificial horizon (derived from position information).

I think I'd be in trouble in a Tcart in IMC and heavy turbulence.

Icing up and losing your airspeed indicator wouldn't be a bit of fun either - the GPS groundspeed won't do you any good for staying level with a headwind or tailwind.

Get a safety pilot with some imagination and aerobatics time for a fun ride. My primary instructor was able to put the airplane into the damndest positions while pulling 1.00 Gs. Really an education about how fast things can go from OK to almost-in-trouble without visual references.

My PPL checkride examiner just had me close my eyes under the hood and fly the airplane. I thought I was doing a great job - until he said "recover." About 30 seconds into it... Talk about a lesson in not being able to trust your senses!

One BFR examiner, after noticing that I like to bounce the stick on short final to judge my airspeed, decided it would be fun to mess with the trim while he had the airplane and I was staring at my feet (in a Champ with a heavy stick). He'd take the airplane, pull a few Gs, put it back in straight and level cruise with the trim ALL the way one way or the other, then sit back and giggle while I thrashed about the sky trying to figure out why nothing felt right.

[Dan Mahalak]

Re: Adding turn and bank

you would be surprised at what your plain jane panel mounted compass will do..tells more than your heading....

look at it next time you turn....bet your turn indicator needs will diminish, at least for VFR conditions. Standard rate turn, no problem, no vsi, no problem, no VFR...Big Problem.

[stormman]

Re: Adding turn and bank

Kinda like a gun , Better to have one and not need it than to need one and not have it. I Think R C will agree on that one

GO with your instinct Dan , do the T & B.

[whake]

Re: Adding turn and bank

I have an electric Turn coordinator ( T& B ) The smallest 3 1/8 th that I could find. It draws about 1/3 amp from my portable battery. I had to mount it from the front of the panel because of interference with the fuel tank, works great, after I solved the radio interference from the new brushes on the gyro motor. I like the idea of having partial panel capability, just in case I ever get caught where I am not supposed to be. My plane had a failed vacuum T & b that I removed. Turn coordinators are always on Ebay.

[Ron Coleman]

Re: Adding turn and bank

A lot of what I have is old, mostly pre 50's. I like the simple beauty and brute force lines of old tools and machines. But I have no romance with their original condition. Almost everything that we acquired in those tough minded days was tricked out, pumped up, and personified one way or another. Guns, cars, motorcycles, houses, boats and airplanes were all "fixed" because they were not quite good enough "we couldn't afford to get the best", or we could make it better. I bought a head light and a fox tail for my Western Flyer bicycle, reshaped the stock on my Model 12 Winchester 12 gauge pump shotgun, put a spot light on my '33 ford 2 door sedan, put running water and indoor toilet in the house (1947), and when I got it, I put a vacuum operated turn and bank in my 1946 Taylorcraft Ace.

Now, vocally, I am as macho as the next guy. I always said that if it had wings and could fly, I could fly it (in the old days--now I know better). But in the real world, I would like to live to fly another day. I wouldn't be without a turn and bank in the plane, except for the ultra-lite.

Just like I never come home late at night with out 8 loaded cylinders in the truck and 6 in my pocket. Better to be prepared.

good flying
Ron C
N96996

Hi Norm!

[Howard Wilson]

Re: Adding turn and bank

Ron, How did you mount the 12 gauge on the western flyer?? howard

[Tom G]

Re: Adding turn and bank

D. Grimm said "I took mine out. I have a small venturi and a turn and bank instrument that works but cannot be overhauled. (radioactive paint) Would love to trade it for most anything."

What is this about radioactive paint?? Is this the glow in dark surface? I have a turn and bank in my airplane that works fine but if this is what I think it is I may have the same thing. Is this dangerous?

[taylorcraftbc65]

Re: Adding turn and bank

Only if you scrape it off and eat it. It's just some left wing "big brother" trying to protect the public from everything. Sabrina