The Hangar

rbp

14:01

this helicopter aerodynamics question is driving me insane

they are all just right enough to be correct from an aerodynamics standpoint but all wrong about terminology or how the helicopter is actually controlled

Farhan

14:30

@rbp The question about trim?

rbp

9

Q: How do helicopters turn using rotor?

I know that airplanes use rudder to turn, and use elevator for nose up and down. How do helicopters change their altitude and how do they make turns?

Farhan

Well in that one, OP said that rudder is used to turn. One can turn using ailerons too, cannot one?

@rbp You didn't answer it???

rbp

i'm writring one right now

@farhan anyone who says that the rudder is not used to turn has never flown in MCA

Farhan

@rbp MCA?

rbp

@Farhan minimum controllable airspeed

Farhan

14:37

@rbp Ah, I was thinking about this.

rbp

oh yes, that too!

Minimum control speeds

Minimum Control speeds (VMC’s) are so-called V-speeds that are included in the Limitations Section of Airplane Flight Manuals (AFM) of all multi-engine airplanes. In general, a Minimum Control speed is the calibrated airspeed below which directional and/or lateral control of an airplane (i.e. the desired heading and/or bank angle) on the ground (runway) or in the air can no longer be maintained by the pilot after failure of a wing mounted engine, or while such an engine is inoperative, as long as the thrust of the opposite engine on the other wing is at the maximum (takeoff) setting. VMC’s are...

casey

@rbp the only thing missing from those answers is a bit of discussion on gyroscopes for completeness. e.g. to create lateral motion to the left the blade pitch changes to induce a downward force directly forward and gyroscopic precession causes the downward force to be manifested 90 degrees away in the direction of rotation, causing the downward tipped rotor disk to the left.

rbp

@casey i am conposing a complete answer now :)

casey

:)

rbp

15:06

@casey have a look now, i welcome your feedback aviation.stackexchange.com/questions/11709/…

and everyone elses

i think this is the only truly correct answer, both in terms of aerodynamics and gyroscopic physics, but also in terms of aircraft design and of piloting

casey

+1

rbp

15:45

@casey thanks

Farhan

16:13

3

Pondlife

16:32

@rbp I've only edited my question once and I hope it's clear. Originally I thought that all the red airways were lettered B, but when I found the A, R and G airways I could see that the chart legend did in fact have the answer, that's why I removed the reference to it.

rbp

@Pondlife our edits crossed

Pondlife

@rbp That can happen :-)

rbp

upvote my heli answers and I'll forgive you

Pondlife

@rbp Tempting... ;-) You might want to include this in your answer, BTW. It gives some additional background on the ATS routes.

rbp

well, I think @voretaq7 knows more about this than me, so i've suggested he write the answer.

but i'll give it a shot

voretaq7

16:38

@rbp your answer is pretty complete

rbp

ok

voretaq7

I used to know where all the airways were but that trivia has long since leaked out of my brain (I know Blue is in the keys, and Green is in Alaska, I don't remember where Red and Amber are)

Pondlife

@rbp I deleted my comments, BTW, because they don't make sense any more

voretaq7

I'm also pretty sure there are no pretty lights on the NDBs anymore

Pondlife

@voretaq7 AK has R/A as well, I don't know if they're anywhere else too. This says the colour depends on the heading of the airway, but the ones I found in AK don't match that at all

voretaq7

16:44

@Pondlife Alaska is Special. Every section of the FARs ends with the phrase "Except in Alaska" :)

Pondlife

@voretaq7 Exactly. I started wondering where I could find some other red airways because I didn't see any in the south-east and my immediate thought was to check Alaska because they have all the odd stuff :-)

Farhan

@voretaq7 IRS also follows that. You'll be charged hefty taxes ... except in Alaska!

voretaq7

@Farhan To be fair that's because you can make hefty money ... except in Alaska (unless you're in the oil business)

and we don't tax the oil business because we likes our oil.

Pondlife

@voretaq7 And our cheap avgas... 'Cheap' being a relative term here, of course!

rbp

@Pondlife @voretaq7 ok, my edit is done and my snarky comments deleted

Pondlife

16:49

@rbp Nice map!

rbp

:)

voretaq7

@Pondlife Cheap by Alaska standards means $8/gallon like at JFK? :)

rbp

map makes it wasy to see why they are prioritized GARB

Farhan

@rbp The 2nd and 3rd references are missing.

rbp

fixed

Farhan

16:56

@rbp That map wasn't readable, so I added the reference for the higher resolution one.

rbp

<bows>

/me bows

heh

Farhan

@fooot I was about to do that edit :)

rbp

interstingly, the NY-chicago-SLC-SFO route corresponds to the railroad route

and I80 mapsofworld.com/usa/highways/maps/us-interstate-80-map.jpg

Pondlife

@rbp IFR ;-)

rbp

@Pondlife indeed!

etsy.com/listing/191236294/…

voretaq7

17:12

@rbp A lot of the early airways were based on railroad and highway lines - that's what you'd follow if you didn't have a radio

rbp

or a GPS :)

voretaq7

@rbp A WhatNow?

rbp

and a pair of turbocharged engines

voretaq7

I've got a DME. That counts for something right? :)

rbp

speaking of DME -- read this very interesting old article terps.com/ifrr/may96.pdf

the DME arc is on a VOR, final is a DME colo'd with the ILS

casey

17:40

aeronav.faa.gov/d-tpp/1501/05222vdtz15.pdf

that is an approach with a DME arc all the way to the runway, and then off to the missed.

rbp

@casey that's awesome!

that should be on every instrument checkride

casey

the place I instructed at had an FTD and when my students thought they had a handle on briefing approaches and flying dme arcs I'd put them on a flight in the FTD and hand that approach to them and just watch :)

rbp

i had the easiest DME arc demo on my checkride

i had had to track the 15 DME arc from the MAP to a hold about 3 miles away

voretaq7

18:33

@casey . . . I wish to fly this approach now.

The funky-ass missed to avoid the restricted areas is particularly amusing.

Dan Hulme

I still think the discussion of the rotor disc tilting could be confusing

because one naturally pictures a single disc tilting like a spinning plate

rbp

think of it like an swing carousel fierceandnerdy.com/wp-content/uploads/2012/05/swing-ride-2.jpg

Dan Hulme

a chair-o-plane

rbp

@DanHulme the other answers are wrong with respect to the tilting of the rotor disk

with certain rotors systems the blades move. with others the blades are connected together and move together.

crap, i've reached 200pts for today

Dan Hulme

your bottom diagram was helpful in that respect

rbp

18:49

@DanHulme unfortunately, people have voted on an incorrect answer

voretaq7

@rbp people also often vote for incorrect political candidates. Not much we can do about that except offer them better options...

rbp

i wonder if it would be better if the question were left up for some number of hours unanswered, and then all the answers are revealed at the same time

the first answer, correct or not (like my red airway), usually gets the most votes

voretaq7

@rbp maybe, but that has other problems (duplicate answers, multiple partial answers, etc.)

Farhan

@rbp Well, that's not always the case.

rbp

we already have duplicate answres and partial answers

usually but not always (why do people think usually or often mean "always")

Farhan

18:56

I noticed that several times my answer outdid the first answer.

rbp

not disagreeing

Farhan

@rbp For this current answer in discussion, the other answer has been posted since 23 hours, yours is only 3 hours old.

rbp

true

Farhan

Still you got 8 votes compared to 20 on the other one

rbp

i am going to call this place and find out if i could be a candidate groups.google.com/forum/#!topic/rec.aviation.soaring/…

fooot

19:00

@rbp I'm proud of myself for holding off on voting on answers for that one.

voretaq7

@rbp I also don't think the other answer is inherently "wrong" (ok, he calls the anti-torque pedals "rudder pedals" - every fixed-wing guy I know does the same thing, and heli folks know what we mean). Aome of the comments under it have substantial issues, but the core explanation seems sound unless I'm missing something?

casey

the answers are complimentary, though I prefer rbp's take on it

rbp

its correct as far as aerodynamics are concerned, but its wrong as far as how helicopters work or how pilots fly

holy crap, i may have a glider pilot job!

Farhan

@rbp How much they are paying?

casey

the first answer treats the flight dynamics as a black box that only addresses pilot input to the system and the analog to fixed wind flight. Rbp's answer actually describes the rotor and how the the turn actually works.

rbp

19:09

@Farhan i didn't ask because I don't care

casey

and correctly invokes gyroscopic precession, which any proper answer on helicopter flight must do :)

voretaq7

@casey likewise

Dan Hulme

@casey complimentary? "that's a really well thought-out question, and only an inquisitive and clever person like you would have thought of it"

:-)

voretaq7

@casey It does not however invoke a sacrifice to Baal, which anything involving a helicopter must do :)

"OK, step one - slice this goat's neck open and spray the blood on the main rotor.
Alright, now that the demons have been appeased we can get in this upside-down hand mixer and attempt to commit aviation."

Dan Hulme

is it worthwhile learning to fly a helo?

rbp

19:14

blender, not mixer. you know how picky i am about terminology

Dan Hulme

there is a school in the next portacabin across from my flying group

rbp

@DanHulme so fun!

Dan Hulme

and I've always thought it was pretty cool

rbp

the woman said i was a very promising candidate and would I send her my flying resume and provide 2 rferences

voretaq7

@DanHulme I would like to learn to hover one someday

but zomg kerspensive

rbp

19:16

1. go to costco
2. buy a case of beans
3. eat
4. ....

casey

@voretaq7 presumably that is taken care of in the factory, pre-delivery. I'm no expert on the details of the ritual though.

rbp

the discovery flight in the copter is beguiling.

casey

@DanHulme only if you want to own on for personal flight or fly on professionaly. Quite expensive to rent for recreation.

voretaq7

@casey I'm not getting in that thing unless I'm DAMN WELL CERTAIN the demons have been appeased RECENTLY :-)

casey

I have 20 minutes in an R22 and that cost me $60!! (2002 prices, ymmv)

rbp

19:18

you did see the picture I annotated.. there is a Jesus Nut

Dan Hulme

I saw that

voretaq7

@casey Last I heard the R22 they were training in at Republic rented out for $275/hr

that was a few years back

rbp

that's about right

usually includes instruction

casey

for $275 an hour, give me an airplane with two engines please.

rbp

44s are in the 400 range

casey

19:19

yea, and once you are done training you don't want to be playing around in the 22 anymore

rbp

i have seen nearly timed out R44s for under $400/hr

voretaq7

@rbp I don't recall if instruction was included or if that bumped it up to an even 300/hr, but still gaaaaak!

What soured me on helicopters was learning that the R22 had a calendar airframe limitation

rbp

siriusflying.com/discovery

casey

I still remember renting a C150 for $45/hour (wet) if you bought time in $400 blocks.

rbp

john pyle was my DPE for private and commercial heli. on the commercial, he mostly told me vietnam stories

john runs sirius flying

Dan Hulme

19:21

the R22 in Cambridge is £275.00/HR + £15 landing fee

that's US$417/hr

casey

@DanHulme can you ask your passengers to jump from a 0.6 m hover and avoid the fee?

Dan Hulme

(that's for instruction, not just hire)

voretaq7

@DanHulme Continuing the grand tradition of UK pricing: Take the US price, cross out $, and write in £

Farhan

@DanHulme What's the landing fee for?

Dan Hulme

no idea

Farhan

19:27

If you land safely, it's £15; otherwise cost of R22

Dan Hulme

they do have to cross the main runway to get from the helicopter parking to the low-level practice area, so perhaps they get charged that by the airport

casey

@Farhan big airports typically charge landing fees. In parts of Europe (and Canada) you'll pay fees for just talking to ATC, flying approaches, etc

voretaq7

@casey In the US too one day. They keep trying...

because you know thats how you improve safety: Discourage pilots form using ATC services.

Farhan

@voretaq7 Yup, and landing too.

casey

yep, AOPA and EAA can only do so much lobbying. It'll happen slowly but it eventually happen completely :/

voretaq7

19:31

As much as I think AOPA is a bloated corpse these days I throw them a few bucks to keep screaming about that

we already have enough people doing stupid things, we don't want to add a financial incentive to be stupid. "1500 foot ceilings, barely 3 miles viz, and steadily deteriorating -- but I'm not going to file IFR and shoot an approach because it's gonna cost me $50 to talk to ATC!"

casey

I'm currently seeing how many "last final offers" AOPA is going to send me to renew my lapsed membership.

I keep getting last chances to sign back up, my luck must run out at some point...

Farhan

@casey It won't.

When you renew, ask them to send all the magazines you missed and they'll be very happy to do that.

rbp

i rotate between aopa, eaa, spa, and ssa, depending on what i'm interested in flying when i'm reading my mail

casey

@Farhan i was surprised that last time I tried this experiment and renewed after 2 years of lapsed membership they still sent me my 10 year lapel pin :)

rbp

i kid you not

casey

19:37

i let AOPA lapse when I was ALPA, and I ocassionally send EAA some money

rbp

i came very close to rejoining the SPA when i saw their booth yesterday at the Crappy Sport Pilot Expo

casey

@voretaq7 perhaps we'll see a resurgence in the use of contact approaches. No flight visibility but I can see straight down -- I'm over the supermarket so thats a 3 mile final and if I follow this road...

rbp

19:50

I think of a contact approach as an IFR analog of SVFR

Who has a recommendation for online logbook software

voretaq7

@casey . . . I'll crash right into the radio tower because the Fairway and the Safeway look identical from above!

@rbp LogTen seems to be popular

rbp

Oh give yourself more credit @voretaq7

Scud running is not that hard on your own turf

voretaq7

@rbp Your right - there are no radio towers near FRG... I'll get caught in the driving range's net instead :P

@rbp No it's not. I've done it under what I'd consider low-ish (2000-2500-foot) ceilings, but always with good forward visibility (~8 miles)

rbp

Need 1000ft ceiling

voretaq7

It's also not particularly fun - I like having distance between me and the ground. I'm funny that way...

rbp

19:59

heh, I guess we have a different view of low :)

voretaq7

@rbp we have lots of 500 and 600 foot towers around these parts. You fly right over them on normal VFR arrivals...

Also the entire sectional is lemon yellow 'round these parts so there's some other legalities to consider.

rbp

They're clearly marked/lit what's the problem

What's lemon yellow mean?

voretaq7

@rbp hahahahahaha lit that's a good one.

@rbp It means "congested area", but the practical implication is "If you're not 1000 feet above or 2000 feet away from obstacles don't worry - the FSDO is right in the terminal, it's a short walk for them to bust you"

rbp

oh you mean populated. Right. I would stay over the highways. Take the lie to the moshulu exit 3 and then the sunrise westbound till you hit exit 80..,,

voretaq7

yeahhhhh no:

rbp

20:05

ok then!

I need to get you up in a glider this summer.

voretaq7

You could thread your way in from the south shore SVFR, that's about it.

rbp

The Bay Area has a daily marine layer, sometimes down to a few hundred feet. But the local pilots have good routes for getting around

When it's legal

voretaq7

@rbp One day I'll go do some glider rides out at Brookhaven. Not sure I'd make much use of a glider rating, but I'd like to get some glider time.

@rbp yeah they have a lot more options out there where you can get down low

rbp

I've flown a heli from Napa to San carlos over the bay itself when it was OVC005 but good viz

voretaq7

we have people. people with phones. who like to call up and cry about the big loud airport that's been there since the 1930s. :-/

rbp

20:10

Got higher closer to SFO so it wasn't a problem over land

No no, we need to drive up to wurstboro NY where there's thermals and ridges, not just tows

voretaq7

@rbp . . . points at airport

Fly. Cheaper than tolls.

(seriously, it is)

rbp

Oh yes fly to wurstboro!!!

In your Cherokee.

What's the free online logbook

voretaq7

Don't know any that are free - honestly I just scan the pages from my logbook and stick them on a server somewhere

(when I'm done transcribing the plane's logbooks I'll start doing mine. There's a lot less of it, could probably knock it out in a day...)

casey

@rbp that can potentially get you into trouble too around there. the expressway visual into LGA keeps you right over highways and somewhat low

rbp

@casey if the expressway visual is in use, doesn't that mean its, uh, visual?

or are they still in the clouds until closer to the airport

voretaq7

20:21

<stares at California charts> it'd be nice to fly somewhere without people :P

rbp

tiptoe visual @SFO needs, i think, ceiling above 3,000

voretaq7

@rbp I think all the LGA visuals are 3000 feet and 5 miles?

rbp

155.178.201.160/d-tpp/1501/00375TIPPTOE_VIS28LR.PDF

Pondlife

@rbp myflightbook.com is free and very good. The developer takes donations if you feel it's worth it

rbp

Weather Minimums: SFO 2400’/5 (If AWOS inoperative, SQL 2400’/5)
in eastern quadrant (030° clockwise to 120°) and San Mateo AWOS
Weather Minimums: SFO 2100’/5 or SFO 1000’/3, with 5 mile visibility

@voretaq7 not only are there fewer people once you're past 25DME SFO, there a LOT of airports, of all shapes & sizes

voretaq7

20:25

we have surprisingly many airports on Long Island.... most surrounded by people that like to complain about their existence.

Farhan

@voretaq7 Those must be retired people who have this hobby to call the airport and complain, in addition to gardening and watching TV.

voretaq7

@Farhan A lot of the ones that gripe about Republic are.

Farhan

20:41

@voretaq7 I saw that happening once. A woman called the airport to complain that an airplane passed over her house and made a lot of noise. She gave her home address. Turned out she was living right under base-to-final turn.

voretaq7

@Farhan "Yup. Get used to it."

Farhan

That was the traffic pattern.

voretaq7

Urban Planning Fail?

Dan Hulme

a few years ago in Cambridge there was uproar in the paper because of a low-flying Hercules over the town, because it was practising for the Farnborough Air Show

rbp

23:05

so, i spoke with the person hiring for the glider sightseeing pilot job, and she said that I am a very promising candidate (and so far the only one!), and to send her my docs and 2 references

falstro

avherald.com/h?article=48050a1f&opt=0

Heh. Woops.

Dan Hulme

23:23

the hole is suspiciously neat and rectangular in the photo

fooot

Yeah, doesn't seem like a typical random sink hole.

voretaq7

@fooot former storm drain improperly capped off?

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