10,000 Feet for RAA - Uses and Threats

[Spriteah]

Interesting stuff.

 

So DJ. If I fly my plane to IAS VNE at any height that is within the flight manual, and, the ASI is accurate can I exceed VNE in your oppinion? When I say can I what I mean is will I (true airspeed) and is this really exceeding VNE or has this been factored into the design testing of the aircraft?

 

Jim.

 

 

[djpacro]

I should've just pointed out the excellent material already on this site http://www.recreationalflying.com/tutorials/groundschool/flutter.html#limiting_airspeeds

 

 

[rgmwa]

.. and im gonna stop there because i think im starting to ramble and i doubt this will make much sense, unless anyone that understands what im trying to say can say it better than i can....:thumb_up: - Iggy!

I think I get it. Don't exceed Vne?

 

rgmwa

 

 

[eightyknots]

Pretty straigthforward, NE = never exceed

 

 

[ben87r]

So now im confused! this is all off the previous link, and says VNE is IAS

 

Flight at airspeeds outside the envelope (or at inappropriate speeds in turbulent conditions, or when applying inappropriate control loads at high speed) is high risk and can lead to airframe failure. Vne is the IAS, specified by the designer, which should never be intentionally exceeded

 

Vne for light aircraft is always specified as an indicated airspeed and marked as such on the ASI (the red line). For most ultralight aircraft, only one Vne is specified in the Pilot's Operating Handbook or aircraft flight manual and that value is probably conservative and applicable for operations below 10 000 feet amsl. However, some ultralight aircraft have a capability for achieving considerable altitude and the designers have felt it wise to limit maximum speed to a particular true air speed.

 

For most recreational light aircraft only one Vne is specified in the Pilot's Operating Handbook or aircraft flight manual. That value is probably conservative and applicable for operations below 10 000 feet amsl. The designers of most piston-engined GA aircraft specify one fixed-value Vne for operations up to the service ceiling; that value is represented by the fixed red line on the ASI. However, a minority of GA aircraft have supplementary lower-value Vne for operations in altitude bands above a stated altitude — perhaps above 10 000 or 15 000 feet. This approach to Vne specification is common with sailplanes.

 

A very few aircraft designers select a true air speed value as a limiting airspeed applicable from sea level. FAR Part 23.1545 © requires that "If Vne varies with altitude, there must be means to indicate to the pilot the appropriate limitations throughout the operating altitude range"

 

 

[djpacro]

So now im confused! this is all off the previous link, and says VNE is IAS ........

Vne for light aircraft is always specified as an indicated airspeed and marked as such on the ASI (the red line). ... and the designers have felt it wise to limit maximum speed to a particular true air speed.

 

.........

 

A very few aircraft designers select a true air speed value as a limiting airspeed applicable from sea level..../QUOTE]There are two aspects to this:

 

1. The designer may choose a constant IAS as design dive speed or choose to have TAS as a limit - the boundary of that airspeed limit in combination with the achievable altitude (or a specified altitude limit) is the aeroplane's flight envelope. The certification testing should ensure that the appropriate airworthiness requirements are satisfied throughout.

 

2. VNE will be specified for pilots as an IAS. If VNE was determined from a TAS limit then there will be something like that table showing IAS for different altitudes.

[Spriteah]

See this topic is not clear. A previous post expressed caution of exceeding vne calculating on ias which I found disturbing. The more I read the more I trust the asi and vne shown on that instrument. Unless my pilot handbook says different.

 

Jim

 

 

[poteroo]

Stop worrying about VNE, and consider your Vno and Va speeds for the aircraft. If you fly a faster aircraft - then start thinking about VNE as being your TAS.... in any case read the VANS article on www.vansaircraft.com. It's more likely that you'll encounter turbulence on descent, and this is when it's important to throttle off and get back into a safe speed range.

 

happy days,

 

 

[facthunter]

It's always worth-while to be aware that at height your indicated airspeed is less than your ACTUAL TAS. If turbulence is expected the plane should be slowed down to reduce the dynamic loads on it. In severe turbulence you are trying to keep a margin above stall for controllability and below a speed where a gust induced load will threaten the structural safety margin of your aircraft. Stall speed still relates to INDICATED airspeed, with the usual variations as a result of manouvering/gusts.ie dynamic loads...Nev

 

 

[HEON]

Interesting discussion on Vne. Have read of gliders up high (20000-30000ft plus) getting into real problems.

 

Not rearly mentioned is the temperature. Took a Drifter to 8500 to get over some cloud last year (where the rocks went to over half that) in winter. Gives a whole new meaning to cold even in freezer suit, gloves, helmet, and Ugg boots!

 

 

[facthunter]

Coldest temperature I can recall was minus 54 degrees centigrade. You wonder how the alloys don't get brittle. I was up fairly high in a tiger and the instruments had frost of them and there was ice on by mustache from breathing. I believe Geoffrey De Havilland got a Gypsy moth up over 23,000 feet Not a bad effort...Nev

 

 

[Student Pilot]

We had a bloke who regularly used to fly over 10,000 in a Drifter. So that would be a handlebar mustache Nev?

 

 

[Guest ozzie]

I think you are all freaking out about to little. Just stick to the reference speeds in you POH. Stall speed goes up a bit VNE comes down a bit . ever heard of 'coffin corner'? More important as already stated is turbulent air penetration speed. You are not flying a Lear 55 @ FL45. Be more aware of the aeromedical side of things. Smokers and those with poor circulation problems will have problems with decision making skills and vision etc. Hypoxia is an interesting subject. Partial pressures can in some situations lead to the 'bends'. Remote possibillity but it has happened. don't worry to much about your aircraft unless you plan on taking off and landing at that altitude. The human body is more of a worry.

 

Ozzie

 

 

[frank marriott]

Lets be realistic, we are talking about 10000feet not FL350 or the like. More important for those who have not previously used 5 to 10 is fly at the correct levels, monitor the relevant AREA FREQUENCY [not CTAF unless you can monitor two or more freqs] and be aware of other climbing and decending aircraft, select 1200 on your transporder [if fitted naturally].

 

Transition layer etc is only relevant above 10000ft and you will be there illegally in a RA registered aircraft anyway.

 

Remember it is volunary - if you are not happy with performance/air legislation matters at these heights don't go there until you are.

 

Keep inside your comfort zone and enjoy the flying.

 

Frank

 

 

[facthunter]

Ozzies right about the oxygen effect. If you are older and enjoy a few beers and go in lifts instead of walking a few stairs the you may easily suffer some ill effects. Another thing ( since we are discussing all things ) to take into account of, is the time it takes to get down. You do have the ability to glide further but it takes takes time do the descent. You may have a reason to want to put the plane down quickly and also a long descent with no power on means a pretty cold engine when you enter the circuit. The OAT at 10,000 is about 20 degrees colder than MSL temp. so if it is a 20 degree day on the ground, it is zero at 10,000 ft so closing the throttle fully is a bit hard on the engine. A partial power descent without getting a high indicated speed would have to be commenced easily 15 minutes out. None of this is really big deal but it is all something to take into consideration. Nev

 

 

[eastmeg2]

What are the USA altitude rules for UL's & Trikes? (N - Numbered)

 

I'm going to Oshkosh this year. If I were to line up a Trike CFI with an N-Numbered Airborne or Revo or P&M 2-seater trike, what are the limitations besides any FAA altitude time limits without bottled oxygen?

 

 

[rgmwa]

Coldest temperature I can recall was minus 54 degrees centigrade. You wonder how the alloys don't get brittle. I was up fairly high in a tiger and the instruments had frost of them and there was ice on by mustache from breathing. I believe Geoffrey De Havilland got a Gypsy moth up over 23,000 feet Not a bad effort...Nev

A bit off topic, but I just read in the Flight Safety magazine that the highest recorded birdstrike was an airliner hitting a vulture off Africa at 37,000'. That vulture must have been wearing an overcoat and carrying an oxygen bottle.

 

rgmwa

 

 

[Guest ozzie]

Hmm Decent profile. I was taught that mainly for passenger comfort and engine management that a longer slower decent (IE started further out from your destination) at around 500fpm will allow you to have a higher power setting to keep the temps up or in the green (I must remember that all my long trips at height were all in turbines) and give your passengers a more pleasant ride and not affect their ears/ nerves, than arriving almost over the top then barrelling down. Most GA piston aircraft have cowl flaps with the exception of a few like Islanders and Chieftans that have to be 'Driven' down for several reasons .Shock cooling and overdriving are two. If you have cowl flaps then button them up for the decent, if constant speed then a good rule of thumb is to reduce power 1 inch MP per thousand feet. No doubt there are other guidlines so take it all in and talk to LAMES and more experienced pilots. Bank runners are a good wealth of knowledge. All the new engine managment instrumentation should remove any chance of damage if an eye is kept on them.

 

Ozzie

 

 

[facthunter]

Cheiftans have cowl flaps. If we are going to levels like this I would recommend the fitting of cowl flaps. I believe in fitting them even if you don't go that high, except in the most elementary installations. People who like everything FADEC wont like it but the reality of cooling management still exists. Nev

 

 

[Guest Crezzi]

What are the USA altitude rules for UL's & Trikes? (N - Numbered)I'm going to Oshkosh this year. If I were to line up a Trike CFI with an N-Numbered Airborne or Revo or P&M 2-seater trike, what are the limitations besides any FAA altitude time limits without bottled oxygen?

From memory, the FAA VFR rules were something like - below 12500 = no need for oxygen, above 12500 and below 14000 = max of 30 minutes without oxygen and above 14000 oxygen required. I think these limits applied to the pilot only - pax only had to use oxygen above 15000.

 

AFAIK there aren't any different limits for N-reg LSA trike so I imagine these would be applicable. I've not been to Oshkosh but I don't think you'll need oxygen there ;-)

 

Cheers

 

John

 

 

[facthunter]

think the reqqirement for oxygen to be carried/used for crew is lower in australia. (10, 000 feet? ) Nev

 

 

[Guest Crezzi]

think the reqqirement for oxygen to be carried/used for crew is lower in australia. (10, 000 feet? ) Nev

Thats correct - the difference in USA is because they have some much taller granite which VFR may need to cross. I think Canada & NZ have similar rules to FAA for the same reason.

 

 

[eastmeg2]

I'll be spending a week near the "taller granite" after Oshkosh.

 

 

[Guest eland2705]

Good afternoon all,

 

Just a comment, it is an allowance, not obligatory. If you don't want to fly at 10K' then you don't have to.

 

Surely it is up the PIC to make the call as to whether he/she is happy/competant/equiped to acsend up there?

 

 

[Guest ozzie]

Cheiftans have cowl flaps. If we are going to levels like this I would recommend the fitting of cowl flaps. I believe in fitting them even if you don't go that high, except in the most elementary installations. People who like everything FADEC wont like it but the reality of cooling management still exists. Nev

Quiet right they do have cowl flaps. my bad. been a long time since i worked on them. I remember a night takeoff sitting in in the back you can see inside the cowls thru the little grills the turbo runs so hot at full power the snail runs cherry hot and you can see inside the turbo. spooky. also remember controllers being asked to consider the limited decent rates for them as well. the engines do not like over driving as it hurts the crankshaft. you have to 'drive' them down.