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C150 vs C152

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Old 23rd Oct 2008, 07:47
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Grrr

I learnt on '150 F models at Marshalls. Full flap go-arounds were part of our training, but you had to re-trim very quickly while slowly retracting the flaps; with your third and fourth hands you flew the aircraft and handled the throttle.
By the way, there is a BIG difference in aerofoil section between these early '150s and later marks/'152s. With these early ones, we were taught the following short takeoff technique: full throttle on the brakes with 10 deg flap; release brakes; rotate at 45 mph and initial climb at 50 mph. You could never do this with the later aerofoil; I know, I tried it when I checked out at Denham a few years later on their '150Gs (frightened the instructor to death too!)

Edited from 20 deg flap to 10 deg flap; haven't flown one in about 17 years!!

Last edited by chevvron; 24th Oct 2008 at 09:14.
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Old 23rd Oct 2008, 22:12
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Full power, retract flaps immediately to 20 degrees. It'll climb away nicely.

Don't mistake the nose down trim change for sink! Flaps up - nose up.
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Old 24th Oct 2008, 02:32
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So, the target speed for the full flap climb in a 150 would be about 54kts (don't know about the 152)... at which it should climb at least as well as prescribed. How many folks would be willing to pitch for that?

Why would it not climb - see above.. this would be a case where an 'extra 5kts for the wife and kids' would not help. Also note that the prescription is 'at sea level' (presumably standard conditions). High density altitude will really hurt that..

I don't think anyone's suggesting that it's a smart idea to do this, or that you shouldn't retract if in any way possible. Merely that it is possible, contrary to popular belief..
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Old 24th Oct 2008, 08:19
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Yeah, if the wife and kids are so heavy that you need the extra 5 kts, you'd be better off with a more powerful plane. Generally, speed exceeding the manufacturer's recommendations for given a phase of flight is not benificial as expected. Drag increases as a square of the speed, so if you have drag, it is increasing faster than anything else, who wants that?

And, no, the fact that something is possible in an aircraft, and a required design requirement to be shown, does not necessarily make doing it a good idea for casual undertaking by low experience pilots.

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Old 24th Oct 2008, 09:15
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Please note 'edit' in my entry of yesterday. STO technique is 10 deg flap not 20!!
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Old 24th Oct 2008, 10:33
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Hey SFCC whats with all this venom ?
cpl4hire is talking utter bohoolicks. Just like most other people that have never spent enough time reading their books.
I was only trying to help the guy by suggesting he gets the aircraft cruising in the right attitude (i.e. not slightly tail down) and increasing the power slightly to 2300 RPM.
This was something he could (and did try) on his next outing (with good results).

On the matter of C150 Go Around with 40 degrees of Flap. Yes, it is possible to climb away but the resultant rate of climb is truly pathetic and when I did it as a Rookie one hot summers day I was only able to get away with it by flying between two trees on the extended Runway centreline!
I note Pilot DAR (who also slagged my suggestion for gettiing the most out of the Aircraft in cruise) did at least one of his 40 deg flap go arounds in the winter.

Regards,

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Old 24th Oct 2008, 11:28
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Winter does create very pleasing performance improvements. Certainly account must be made for the affects of a hot, humid day. The climb performance of a 150 with full flaps out is, as I have previously stated, pathetic. The requirement from the design standard is 1:30. That means that during flight testing in (or corrected for) a standard atmosphere, the 150 demonstrated a change in altitude in a mile of 5280/30=176 feet, or probably 176 feet per minute if you're doing at 60 MPH. If in doubt, go up high and try it. I would have, and reported back by now, but I'm working in Germany this week, and not near my plane.

Pilots of broadening flying skills need to get used to aircraft with non-stellar perfomance. Why? Once you are truly comfortable handling a plane with a best rate of climb of 176 feet per minute, you'll be ready for the single engined performance of some twins when heavy. Recent flight testing I did on a transport category twin, with externally mounted equipment and wheel skis, produced a negative rate of climb on one engine with 110% power on the other The aircraft did not pass. It would have been a bad day if we'd actually lost an engine after takeoff!

Don't knock poor performing aircraft, learn to deal with them the way the manufacturer intended (oh, I've just been told we're going to fly it again - see ya)

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Old 24th Oct 2008, 13:23
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I should have mentioned that the only time I ever flew a C150 was in Florida, and that the instructor who ended up in the field was flying in the summer. I could not comment on the hours on the engines, but none of the aircraft is new!
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Old 24th Oct 2008, 14:23
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Hours on an O-200 is fairly meaningless, compared to being sure of it's condition. I've flown high time O-200's (3600hrs since overhaul) which were fine, and when disassembled were still fine, and I've flown engines fresh out of overhaul, which were really pretty poor. Sometimes it's the devil you know verses the devil you don't. It's only after the first well done inspection in service you know what you've got.

That said, more than other engine types, O-200's have some tolerance for non-ideal condition, before you really begin to notice a loss of performance in the plane.

In good conditions, you can get a 150 (with 10 flap!) off the ground with 2200 RPM (about 75% power). Yes, it takes a lot more runway, and the climb is poor....
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Old 25th Oct 2008, 05:06
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Reduced power take-off

Pilot DAR. What purpose did the reduced power take-off serve? Seems like an exercise in futility to me.
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Old 25th Oct 2008, 05:38
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For me, a less than full power takeoff, when available space is not a concern, is a zero risk activity (you can always open the throttle to continue if you need to). The benifit for me of doing this in many aircraft types, is be more prepared for a partial power loss during a takeoff, when you are committed to make the best of it. One example of a 25% power loss during takeoff is a stuck exhaust valve on a four cylinder engine, which has happen to me three times. It also provides practice in handling finesse. I remind myself that the somewhat lighter cub I used to fly would get the same load airborne as my 150, and do it on 65 HP - do I need all of that mighty 100 HP? - It seems not! Where this is of the most value to me, is the real finesse required to get a floatplane or flying boat off the water. You can easily cook an engine dragging such an aircraft into the air after an excessive takeoff run. Much better to practice your technique partial power to hone you skills. It makes the availability of full power seem like JATO!

I could be guilty of complacency, if I did not do something to keep my skills up. Whenever I fly with an instructor by circumstance, I ask for a refresher, often I'm told "Oh, you're fine" after a circuit. A complement is nice, but not what I need, it's the challenge to my skills I need. So I gave up on getting it elsewhere, and do it for myself on a regular basis. The people whose aircraft I fly, and the companies who insure those aircraft expect me to keep my skills sharp, so I do.

I think that practice and training are only futile when they are unsafe, wrong, and encouraging poor technique, other than that, if it's safe, and you learn, go for it!

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Old 25th Oct 2008, 07:50
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I did a 'reduced power' takeoff once inadvertantly in a Cyclone AX3 microlight. It was a bit gusty 20 - 25 kt at 30 deg to the runway; I began opening the thottle slowly in case a gust lifted the wing, and as I moved forward I thought 'this seems smoother than I expected'.
It was smooth because I was already airborne on just over half throttle after a ground run of less than 50ft! This particular AX3 stalled at 28kt ias two up, so with a headwind of about 20kt, it didn't take much extra speed to get airborne!!
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Old 25th Oct 2008, 08:22
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Yes, I too became airborne at only about 65% power while on the step taking this photo:



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Old 25th Oct 2008, 08:25
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Flying skills

pilot DAR, if your explanation of why you conduct reduced power takeoff's in light aircraft was intended to impress I am afraid I find it somewhat confusing. Maybe it is because I am a retired professional flight engineer used to using approved procedures and just a recreational pilot. My understanding is that you conduct take-offs at reduced power regularly so that you will be better prepared to handle a partial power loss during takeoff. I fail to understand why, if you believe that you are honing your skills, you conduct the take-off in a non-standard and non-approved manner. I could better understand what you do if you were to use full power to become airborne and, after airborne, reduce power. I am always willing to learn, however I believe the lesson learned must be based on sound principles. You claim that it is easy to cook an engine after taking off from water after an extended takeoff run. I fail to understand how your reduced power "training" has any benefit in the scenario you mention. I have been involved in numerous "de-rated" thrust takeoffs. These were always an approved operation, within clear limits and properly authorised. I am unaware of any published data which covers reduced power takeoff in light piston engine powered aircraft. You mention getting a refresher if flying with an instructor. I would be interested to know what reaction you got from an instructor if and when you carried out a reduced power takeoff. My own personal pre-takeoff planning includes reinforcing my actions. If I were to suffer a partial power loss before airborne I would close the throttle and bring the aircraft to a stop. In almost all cases this course of action would, to me, be preferable to carrying a 'sick' engine airborne. Old fashioned and unadventurous I may be, but I do not believe intentional non-standard operations are justified.
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Old 25th Oct 2008, 12:01
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Wow, a lot to be responsible for... Fortunatately I have very little need to impress anyone here, because really, what does it matter anyway? I just try to offer a tiny bit of experience, which people may adopt as wisdom if they choose...

"non-standard" and "non-approved" have less meaning in the world of general aviation than they do for large aircraft. Indeed, I'm not sure that "standard" has much regulatory use at all in this realm. As for "approved", the regulatory authorities will generally decline "approving" procedures which differ from those required to show compliance with the requirements applicable to that particular aircraft design. Thus, there are many things which are have no status as "approved", only because nobody sought to approve them, because there was no need at the time. That simple fact does not make them unsafe or prohibited. If, during certification, a certain condition was found to be unsafe, yet did not cause a finding of non compliance with the design requirements, it would be "prohibited", thus obviously "non-approved". Spins being a good example. In some aircraft they are expressed as "Approved", in other aircraft, they are "Not Approved", and yet other aircraft they are "Prohibited". The same aircraft could have two of these conditions, depending upon configuration. So, are you legally permitted to spin an aircraft for which spins are stated as "Not Approved"?

Where the flight manual and placards are silent, air regulations otherwise do not prohibit, and it is not plainly unsafe, it is not forbidden to do it. Pilot's training and judgement must be applied. If training and judgement inadequate, get more!

My choosing to takeoff with less than full power on occasion, when conditions are favourable, is to, in other words, "reinforce my actions" for planning to fly the aircraft in unusual circumstances. It is very certainly my preference, to be safe, to set the power at the time of takeoff rather than as becoming airborne - that is the time a change in power could cause an unexpected loss of power, perhaps more than one sought! By the time I reach the altitude at which I would normally consider it safe to start reducing power, I'm already about the completion altitude for my self appointed excersise.

Reduced power practice on the water is as harmless as step taxiing. If the pilot's technique is such that consistanly good takeoffs are made with less than full power on the water (finding and feeling the step with more awareness) full power takeoffs will be accomplished with greater skill. You can force a waterborne aircraft into the air with power, or you can fly it off with power, and much less strain on the engine. You cannot force it off with reduced power. Therefore, if you got off the water with reduced power, obviously your technique was good, and that was the best way. If I have to check myself out in a floatplane or flying boat I have not flown before, I might do this if I have time.

Yes, if I can detect an engine problem, and abort, I would much rather have the sick engine on the ground. It's not always an option. Several times I have had engines turn sick just as I crossed the trees. If you manage the plane properly, and get it back around safely, the engine will be back on the ground, where it should be, for maintenance. If you forget to fly the sick airplane, you'll be in the trees. There are many reports of crashes after a partial power loss, where it is agreed that plan could have been flown to a safe landing.

I differ, in that I firmly believe that non-standard operations are justified, and indeed, vitally important when conducted safely with preplanning, and not in conflict with flight manual, or other regulatory material. In some cases, formal approval is appropriate. For those pilots who can imagine a non standard operation, which they know they have not training for, they can seek out the training. For operators who can imagine using the aircraft for a task which could require modifications, and might involve degraded performance, formal approval must be sought.

Is towing a glider a standard operation? You're sure flying the aircraft with effectively less than full power! Is flying with a draggy external load, which really affects the performance of the aircraft a standard operation? It can have the effect of reducing performance like having less power. I have approved both such types of operations as only two examples where an aircraft will be flying with less gusto than the "normal" version of that aircraft.

As a personal "check and balance" I like to practice out of the ordinary. It broadens the mind. When I test further out of the ordinary, I apply for a flight permit, that extra check and balance for safety.

Flight permit not required for a partial power takeoff in a 150...

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Old 25th Oct 2008, 23:43
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Reduced power takeoff's

pilot DAR, I guess you and I have fundamental differences in our approach to how we fly. If you are an approved test pilot with requirement to explore the boundaries I can see why you feel the way you do. Your profile states that you hold a PPL. No doubt, you have vast experience. I cannot fathom how you, as an instance, can say that "you can force a waterborne aircraft into the air with power, or fly it off with power, and much less strain on the engine". If the engine is operating at full power it makes no difference to the "strain" on the engine whether you "force" the aircraft airborne or whether you "fly it off". All the engine knows is that it is operating at full power. We will obviously continue to "do it our own way". As I said, old-fashioned and unadventurous for me. Happy landings. BTW, your photograph is very impressive.
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Old 26th Oct 2008, 00:23
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I have a few hours in an old Howard DGA-15P - and I'd expect the Beaver to behave the same - and takeoffs are always most impressive. You must open the throttle slowly, so not to run out of rudder authority (especially in a left crosswind!!!).

On a standard day, with a typical load (4100# TOGW), you will be off the ground within 5 seconds of reaching takeoff power (2300 rpm / 36"Hg). At this point, unless you have an obstacle to clear, you can start backing down to 30" and 2000 rpm to conserve engine life - you'll still climb over 1500 fpm @ 85 kt.

Treat yourself to a video!
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Old 26th Oct 2008, 08:35
  #38 (permalink)  
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Yes.

If the engine is operating at full power it makes no difference to the "strain" on the engine whether you "force" the aircraft airborne or whether you "fly it off". All the engine knows is that it is operating at full power.
All the engine knows is that it is operating at full power, and for how long, with poor cooling due to low airspeed. With unpracticed techinque, you can eventually succeed in draging the aircraft into the air, and keeping there because you kept forcing it up below flying speed, and eventually it stayed. I've done it, I'm not proud. Or, using a practiced technique, you can have the aircraft off the water a mile sooner, and speeding up in the air as intended, with the engine being properly cooled. It might still be operating at the strain of full power, but it is much happier being properly cooled. (and a lot less pounding on the airframe as a bonus)

When I have been asked by Transport Canada to evaluate an unproven float installation, ease of getting off the water (due to "deck angle", or choice of propeller) is one thing I'd be looking for. That goes to how long a pilot is likely to operate the engine at full power and below normal flying speed. From a proper step taxi (which would not be sustained at full power), if I can get airborne, I just did a partial power takeoff. If I did not, no harm done, add a bit more power, and try again.

Old Fella, I do appreciate that we might fly using techniques which occasionally differ, and as long as they are safe in each case, I am very happy to think that you are enjoying safe flying, as we all should. Nothing at all wrong with old fashioned and unadventurous, as long as the underlying skills remain sharp.

A small part of the service I perform relative to aviation, is to evaluate a change to an aircraft within my delegated scope, and recommend it for approval, if I find it meets the design requirement. It's a little adventerous sometimes, though I try to keep the adventure to a safe minimum. It has been the case so far, that all of the "adventure" I have experienced while doing such flying has been a failing of underlying maintenance, not the modification.

I'm pleased that you enjoy the photo. I was practicing glassy water landings to keep my skills sharp. As I step taxiied, I looked out, and thought "I want to remember this in my old age", so I shot a few pics. A moment later, things got very smooth. I was flying! I only had 65% power, and had no intention of leaving the water yet!

I salute your enjoying flying in your later years, after an aviation career, I hope that it continues to reward you for years to come!

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Old 27th Oct 2008, 00:31
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I'm a fairly low hours PPL (and only a recreational pilot.. for now), but have came to powered having flown gliders for a few years, and do aeros in both (i.e. I've spun, many times..). Let me throw in a thought, (maybe two) on a bit of a pet peeve of mine

Looking around me at my fellow PPL's (generally around the 100hour mark) they very 'by the numbers'; e.g. 1700rpm, 2 stages of flap on base, etc., etc., Ok, as someone pointed out, the numbers have a habbit of working out.. but they're only 1 solution of many, and a lot seem totally out of their depth with anything non-standard - there's no judgement factor.

That said a significant portion are also terrified of the low speed regime to the point they add 5-10kts to the numbers (speed is safety right?) - we're talking 70-80 knots before getting the nosewheel of a warrior off the ground, and 70+knots over the threshold. Fortunately we're blessed with miles of gorgeous smooth tarmac.

I'm of the opinion that both of the above are a problem - glide approaches, anything other than the 'standard' circuit is 'abnormal', to be feared, passed on the checkride, and forever avoided. We're taught to fear the edges of the envelope, the dreaded stall/spin, but have no idea where those edges really are (it's probably harder to spin than most think.. not that I suggest you go around pushing your luck of course!). I can't help but feel that one day each of us will need that judgement - and judgement is like experience, you get it by doing.

Just as a caveat, I do understand anecdotally, that large 'transport category' aircraft are necessarily by the numbers, not feel aeroplanes. I've only ever sat down the back of those, so I wouldn't know.

Last edited by Mark1234; 27th Oct 2008 at 05:31.
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Old 27th Oct 2008, 03:37
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SFCC, why? cpl4hire gave a good advice. You need to let the plane accelerate a little after leveling off, and then reduce power to around 2300-2400 rpm.
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