Bacon Saver Angle of Attack Indicator
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Bacon Saver Angle of Attack Indicator
I've ordered an Angle of Attack indicator and it's just arrived:
**Link removed...**
It will be clamped to the left vertical wing strut on my Super Cub and I'm guessing that it will require to be certified as a 'minor mod' in conjunction with my local CAA office. Any licenced engineers out there care to comment / give any advice?
Cheeers,
QDM
**Link removed...**
It will be clamped to the left vertical wing strut on my Super Cub and I'm guessing that it will require to be certified as a 'minor mod' in conjunction with my local CAA office. Any licenced engineers out there care to comment / give any advice?
Cheeers,
QDM
Last edited by BRL; 4th Jul 2002 at 23:53.
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The Cub/Super Cub has been around for decades, Mr Piper saw no need for an AoA indicator, I just wonder why you do?
Having flown both PA18-150 and J3/L4 variants, I recall that they were pretty adept at telling me (Mr Average - definetely not a SkyGod) when the wing was producing insufficient lift because of its near stalled condition.
So you've spent your money and you are no wondering about the legality of bolting it on. I'm curious as to how you'll calibrate it?
Interested in answers to both questions.
TIA
Stik
Having flown both PA18-150 and J3/L4 variants, I recall that they were pretty adept at telling me (Mr Average - definetely not a SkyGod) when the wing was producing insufficient lift because of its near stalled condition.
So you've spent your money and you are no wondering about the legality of bolting it on. I'm curious as to how you'll calibrate it?
Interested in answers to both questions.
TIA
Stik
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AOA
Sounds to me if you're interested in AOA its because you expect to be flying slowly. If this is prior to landing I would think that looking at the view ahead could be a tad more important than consulting a device not in your normal scan and which is along for the ride.
Keep it simple and don't trust machines !!
Keep it simple and don't trust machines !!
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qdmqdmqdm firstly no idea as to the answer to your questions - sorry!
secondly to all you "top guns" intent on critisising - whats the main reason you use you airspeed indicators??? that's right its to make sure you don't stall! Obviously it's somewhat important when you are DR. but essentially you are using it to make sure you don't stall in slow flight.
Now as you all patently know more about aviation than the rest of us you will be aware that Stalling occurs when an aircraft exceeds its angle of attack NOT when it reaches a certain speed, although the predictable laws of physics mean that an aircraft will be travelling at a certain speed and a certain number of revs when the angle of attack reaches it's critical point.
Surely a better way of monitoring the angle of attack, is an indicator that measures angle of attack???? Instruments are a grand back up and if you ever fly into cloud you'll realise that they are more realiable than we are if we are deprived of any of our senses. If QDM ends up inadvertantly IMC, all other things being equal he'll have a slightly better chance of surviving than you! and he's probably less of an arrogant so and so than the rest of you as well!!
secondly to all you "top guns" intent on critisising - whats the main reason you use you airspeed indicators??? that's right its to make sure you don't stall! Obviously it's somewhat important when you are DR. but essentially you are using it to make sure you don't stall in slow flight.
Now as you all patently know more about aviation than the rest of us you will be aware that Stalling occurs when an aircraft exceeds its angle of attack NOT when it reaches a certain speed, although the predictable laws of physics mean that an aircraft will be travelling at a certain speed and a certain number of revs when the angle of attack reaches it's critical point.
Surely a better way of monitoring the angle of attack, is an indicator that measures angle of attack???? Instruments are a grand back up and if you ever fly into cloud you'll realise that they are more realiable than we are if we are deprived of any of our senses. If QDM ends up inadvertantly IMC, all other things being equal he'll have a slightly better chance of surviving than you! and he's probably less of an arrogant so and so than the rest of you as well!!
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Kirstey
No criticism intended or implied - just wonder why and how it will be calibrated.
Given your interest in "principles of flight" as per your post, what do you think he is going to do; calibrate it against an ASI or perform a series of stalls?
The fact that it will increase the weight of the aircraft and the drag would be my only criticism, do think that TTHills has a valid point though!
About as useful as a stall warner in an aerobatic mount in my opinion.
Stik
No criticism intended or implied - just wonder why and how it will be calibrated.
Given your interest in "principles of flight" as per your post, what do you think he is going to do; calibrate it against an ASI or perform a series of stalls?
The fact that it will increase the weight of the aircraft and the drag would be my only criticism, do think that TTHills has a valid point though!
About as useful as a stall warner in an aerobatic mount in my opinion.
Stik
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stik,
I do understand that - but I just think every little helps when it comes to staying safe! As for how it's going to be calibrated I can only assume an engineer will do it - I'm afraid I can't spot one gyro from another, the physics of all the instruments are beyond me!
and anyway I fly a PA28 - I think i've stalled it! u can never tell tho'
I do understand that - but I just think every little helps when it comes to staying safe! As for how it's going to be calibrated I can only assume an engineer will do it - I'm afraid I can't spot one gyro from another, the physics of all the instruments are beyond me!
and anyway I fly a PA28 - I think i've stalled it! u can never tell tho'
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Interestingly, Denker says that "many airliners .... that do have fancy angle-of-attack sensors don't make the information available to the flight crew — only to the autopilot". That suggests to me that an AoA-instrument doesn't give you very much in the way of useful information.
Oh, and my PA-28 seems to be very good at telling me how close I am to the criticical AoA without any instruments at all - you get a very noticable pre-stall buffet through the yoke. Admittedly the stall itself is a non-event, but you know it's coming.
I guess the washout in the PA-28 wing means that an AoA indicator is meaningless, anyway?
(edit: just noticed a rather odd spelling of critical
)
Oh, and my PA-28 seems to be very good at telling me how close I am to the criticical AoA without any instruments at all - you get a very noticable pre-stall buffet through the yoke. Admittedly the stall itself is a non-event, but you know it's coming.
I guess the washout in the PA-28 wing means that an AoA indicator is meaningless, anyway?
(edit: just noticed a rather odd spelling of critical
)
Last edited by Evo7; 5th Jul 2002 at 19:28.
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I believe that I'm correct in saying that many mil fast jets are flown on AoA. In fact IIRC final approach in the Jaguar is 8 Alpha.
I suppose that you use the stall warner in a C15x to ensure that it goes silent as soon as you unload once the rudder has bitten, what with all that plan-form drag and a slow entry speed it would be buzzing for days, otherwise!
Kirstey - if it really was a safety aid, don't you think that they'd have been fitted at Lockhaven? How many other light aircraft have them as standard fit? You and most pilots however have an in-built AoA indicator, your inate ability to recognise the onset of a stall as aerodynamic buffet or tailplane burble is felt. Still not sure? - then go get more stall/spin awareness training until you are sure.
I can see it being a distraction and if not properly calibrated either a useless or a dangerous distraction! Hope old QDM didn't pay too much for his gizmo.
Stik
I suppose that you use the stall warner in a C15x to ensure that it goes silent as soon as you unload once the rudder has bitten, what with all that plan-form drag and a slow entry speed it would be buzzing for days, otherwise!
Kirstey - if it really was a safety aid, don't you think that they'd have been fitted at Lockhaven? How many other light aircraft have them as standard fit? You and most pilots however have an in-built AoA indicator, your inate ability to recognise the onset of a stall as aerodynamic buffet or tailplane burble is felt. Still not sure? - then go get more stall/spin awareness training until you are sure.
I can see it being a distraction and if not properly calibrated either a useless or a dangerous distraction! Hope old QDM didn't pay too much for his gizmo.
Stik
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stik,
I am fairly confident I can recognise the early stages of a stall. The fact that light aircraft don't as a rule have an AOA indicator, doesn't mean they are more dangerous with them without! Surely it's similar to GPS - not an essential tool by any means but if a pilot chooses to use one then thats up to them??
I suspect it is a fairly minor mod and won't effect the basic C of G, likewise being as the guy is asking for advice on it's proper installation one can assume he's going to install it properly??? Therefore if it's calibrated properly it can only be helpful!!
Flying an airplane is not difficult the added task of glancing at an extra gague is not going to overload a pilot!!
I won't use GPS I think its "cheating" I get a lot of pleasure plotting a route, tracking VORs and NDBs etc etc.. I wouldn't critise anyone who wanted to use a GPS as a primary nav tool so long as they have skills in other techniques to get them home n case it goes pear shaped!
Ultimatly if QDM can afford an airplane he can afford an AOA! so stop giving it the "I AM" routine and let people enjoy their aviation however they want to do it!
I am fairly confident I can recognise the early stages of a stall. The fact that light aircraft don't as a rule have an AOA indicator, doesn't mean they are more dangerous with them without! Surely it's similar to GPS - not an essential tool by any means but if a pilot chooses to use one then thats up to them??
I suspect it is a fairly minor mod and won't effect the basic C of G, likewise being as the guy is asking for advice on it's proper installation one can assume he's going to install it properly??? Therefore if it's calibrated properly it can only be helpful!!
Flying an airplane is not difficult the added task of glancing at an extra gague is not going to overload a pilot!!
I won't use GPS I think its "cheating" I get a lot of pleasure plotting a route, tracking VORs and NDBs etc etc.. I wouldn't critise anyone who wanted to use a GPS as a primary nav tool so long as they have skills in other techniques to get them home n case it goes pear shaped!
Ultimatly if QDM can afford an airplane he can afford an AOA! so stop giving it the "I AM" routine and let people enjoy their aviation however they want to do it!
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Military a/c find them very useful indeed, in fact they're pretty much vital on high performance swept wings. I don't think it is so vital on straight winged a/c.
Useful in the event of a pitot-static/CSI failure though. Instead of having to guess at power settings he can now just fly a circuit on alpha, much easier methinks. I'm not sure how confident I would be in a DIY one as opposed to one designed for that particular a/c.
The various important AOAs are usually discovered by test pilots through hours of well supervised flights. Be careful buddy.
Useful in the event of a pitot-static/CSI failure though. Instead of having to guess at power settings he can now just fly a circuit on alpha, much easier methinks. I'm not sure how confident I would be in a DIY one as opposed to one designed for that particular a/c.
The various important AOAs are usually discovered by test pilots through hours of well supervised flights. Be careful buddy.
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Well, there's no stall warning on a Citabria, but it still 'whistles' like mad near the stall ... that's a pretty good indicator.
The wallowy handling and high sink rate also give a couple of clues.
The wallowy handling and high sink rate also give a couple of clues.
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I guess we are all different. Whilst I agree that the AOA indicator for a cub / supercub is probably as valuable as an INS, weather radar, and crew bunks if you want to fit one and the CAA doesn't have a problem go ahead. As with any instrument you need to consider carefully what it is telling you and react accordingly.
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Kirstey,
If it is properly/accurately calibrated then all well and fine and I really hope he enjoys using it.
If it is inadvertently calibrated to under-read, ie 10alpha is really 14alpha then it if he relies on it too much it is inherently very bloody dangerous.
Likewise if it over-reads, it probably won't be helping him at all and will merely be a useless distraction that may not enable him to get the best out of the aeroplane.
Off to my hangar to fit aircon and a dehumidifier to my Aeronca Super Chief. I'll then call it it Stik's Super-Cool and Dry Chief and will accept the 300% increase in runway required.
I'm sure that Mr Aeronca would have installed them as standard if he'd had more money to splash about!
Gotta go, the hangar beckons.
Stik
If it is properly/accurately calibrated then all well and fine and I really hope he enjoys using it.
If it is inadvertently calibrated to under-read, ie 10alpha is really 14alpha then it if he relies on it too much it is inherently very bloody dangerous.
Likewise if it over-reads, it probably won't be helping him at all and will merely be a useless distraction that may not enable him to get the best out of the aeroplane.
Off to my hangar to fit aircon and a dehumidifier to my Aeronca Super Chief. I'll then call it it Stik's Super-Cool and Dry Chief and will accept the 300% increase in runway required.
I'm sure that Mr Aeronca would have installed them as standard if he'd had more money to splash about!
Gotta go, the hangar beckons.
Stik
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Wow. I've been away for a day and didn't realise what a hot potato this is! I'm gobsmacked that people find it so controversial.
My reasons for buying and, hopefully, fitting an AoA indicator are very simple and two-fold:
1. The airspeed gives only a crude guide as to proximity to the stall, depending on all kinds of factors such as weight and g. The angle of attack in a given wing configuration at which the aircraft stalls is, however, constant. Airspeed indicators are not particularly accurate, especially at low speeds and the Super Cub excels at flying at low speed. What one wants to know at low speed is precisely how close one is to the stalling angle of attack, not the airspeed, which is frankly irrelevant and represents only a very crude proxy for this, as I said. I therefore think that, especially in the Super Cub it will be a highly useful supplementary instrument.
Interestingly, the US Navy flies carrier approaches pretty much entirely by reference to angle of attack. At low speeds and high angles of attack it makes no sense to fly by reference to airspeed if you can actually measure angle of attack directly. They at least understand this.
It is also interesting that the Super Cub, arguably one of the safest low speed aircraft that exists, also has the highest stall-spin fatality rate by far in US NTSB statistics. This shows that if you push any aircraft to its limits it will bite and actually the pre-stall buffet in my machine is pretty minimal. Although the stall itself is 'benign', you get very little warning and certainly NONE from the ASI which is firmly pegged to the bottom of the clock for ages before the stall. In my book, therefore, anything which gives you more direct AoA information has to be beneficial.
2. Quite apart from its utility in everyday operations, I am looking forward to using and calibrating it as a way of better getting to know my aircraft and its limitations and qualities. Of course, experienced pilots with thousands of hours in Super Cubs have no need of an AoA indicator because they can feel the AoA in their bones, at least up to a point. What I hope is that I will be able to advance more quickly in my feel for the aircraft through the information which an AoA indicator will give me in all phases of flight.
The preference for use of airspeed instead of angle of attack measurement in low speed flying is utterly irrational and a result of ingrained prejudice. To show just how irrational it is, the Tiger Moth used to have such a 'weather vane' AoA indicator which was calibrated not in degrees, but in mph. Ridciulous, but a sign of the irrational dependency we have on mph, knots or whatever.
On a separate note, I am interested that the link I put to the AoA indicator website was edited out. It provides a lot of useful info and pictures of the device. I have no interest in promoting it and in fact the man who sells it does not make it easy to send them abroad. He won't do so and I had to get him to send it to a friend of mine in the US who sent him back a US cheque. My friend then sent it on to me. Hardly a highly commercial enterprise. I understand you don't want blatant, excessive plugs, but are the urls of all commercial operations taboo? Seems slight overkill.
I sit back and await responses with interest!
QDM
My reasons for buying and, hopefully, fitting an AoA indicator are very simple and two-fold:
1. The airspeed gives only a crude guide as to proximity to the stall, depending on all kinds of factors such as weight and g. The angle of attack in a given wing configuration at which the aircraft stalls is, however, constant. Airspeed indicators are not particularly accurate, especially at low speeds and the Super Cub excels at flying at low speed. What one wants to know at low speed is precisely how close one is to the stalling angle of attack, not the airspeed, which is frankly irrelevant and represents only a very crude proxy for this, as I said. I therefore think that, especially in the Super Cub it will be a highly useful supplementary instrument.
Interestingly, the US Navy flies carrier approaches pretty much entirely by reference to angle of attack. At low speeds and high angles of attack it makes no sense to fly by reference to airspeed if you can actually measure angle of attack directly. They at least understand this.
It is also interesting that the Super Cub, arguably one of the safest low speed aircraft that exists, also has the highest stall-spin fatality rate by far in US NTSB statistics. This shows that if you push any aircraft to its limits it will bite and actually the pre-stall buffet in my machine is pretty minimal. Although the stall itself is 'benign', you get very little warning and certainly NONE from the ASI which is firmly pegged to the bottom of the clock for ages before the stall. In my book, therefore, anything which gives you more direct AoA information has to be beneficial.
2. Quite apart from its utility in everyday operations, I am looking forward to using and calibrating it as a way of better getting to know my aircraft and its limitations and qualities. Of course, experienced pilots with thousands of hours in Super Cubs have no need of an AoA indicator because they can feel the AoA in their bones, at least up to a point. What I hope is that I will be able to advance more quickly in my feel for the aircraft through the information which an AoA indicator will give me in all phases of flight.
The preference for use of airspeed instead of angle of attack measurement in low speed flying is utterly irrational and a result of ingrained prejudice. To show just how irrational it is, the Tiger Moth used to have such a 'weather vane' AoA indicator which was calibrated not in degrees, but in mph. Ridciulous, but a sign of the irrational dependency we have on mph, knots or whatever.
On a separate note, I am interested that the link I put to the AoA indicator website was edited out. It provides a lot of useful info and pictures of the device. I have no interest in promoting it and in fact the man who sells it does not make it easy to send them abroad. He won't do so and I had to get him to send it to a friend of mine in the US who sent him back a US cheque. My friend then sent it on to me. Hardly a highly commercial enterprise. I understand you don't want blatant, excessive plugs, but are the urls of all commercial operations taboo? Seems slight overkill.
I sit back and await responses with interest!
QDM
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It is an interesting website, and I also have no idea why the link was removed - it takes all of five seconds with Google to find it (and BRL, that isn't a link to the manufacturer - just saving people a bit of typing in Google). Not sure that I'm convinced, but having seen what you're talking about I can't see the harm either.
Must admit I find high-AoA stuff bl**dy interesting, but that's a thread for Tech Log...
Must admit I find high-AoA stuff bl**dy interesting, but that's a thread for Tech Log...
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Evo7,
You probably know it already, but the book for those who find AoA an interesting standpoint from which to approach the practicalities of flying a light aircraft is 'Stick and Rudder' by Wolfgang Langewiesche. Written in 1944, it remains an absolute classic and, in my opinion, is very readable and understandable, if dated in some of its terminology.
You can find it by keying the above details into a certain .com website which sells lots of books and other things and which has borrowed the name of the large equatorial rainforest spanning Brazil, Venezuela and a number of other South American countries.
QDM
You probably know it already, but the book for those who find AoA an interesting standpoint from which to approach the practicalities of flying a light aircraft is 'Stick and Rudder' by Wolfgang Langewiesche. Written in 1944, it remains an absolute classic and, in my opinion, is very readable and understandable, if dated in some of its terminology.
You can find it by keying the above details into a certain .com website which sells lots of books and other things and which has borrowed the name of the large equatorial rainforest spanning Brazil, Venezuela and a number of other South American countries.
QDM
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This will probably induce even greater apoplexy, but it may be useful for anyone reading this thread who wonders what all this stuff is about, so here goes...
The following is a link to an interesting series of pictures showing a DIY AoA indicator in action on a Super Cub in various phases of flight:
http://www.supercub.org/woe/woe0402.php
(It's a .org website, so dear moderator if possible please don't delete the link.)
QDM
The following is a link to an interesting series of pictures showing a DIY AoA indicator in action on a Super Cub in various phases of flight:
http://www.supercub.org/woe/woe0402.php
(It's a .org website, so dear moderator if possible please don't delete the link.)
QDM