Ski's Flying Blog - December 2006
last updated 03 January 2007
This blog is an ongoing account of my flying career. The opinions expressed within do not necessarily represent those of Cabair, BCUC or OFT.
So with the previous day’s slot cancelled due to (unsurprisingly) the weather, I was a bit surprised to find that the weather at Old Sarum was acceptable today. A tad windy, but it was not out of crosswind limits. However, there was an ominous cloud formation growing on the horizon, so we cracked on after a pre-flight check of the aircraft & a quick re-cap briefing.
But after taxiing out (with a radio this time!), during the power checks, the left magento was showing a drop of 300 rpm – and since the max acceptable drop is 175rpm, we decided to taxi back in. Good taxi practice…and free….but I would have gladly paid to go flying instead! After the attentions of one of Old Sarum’s engineering staff, we tried again, but this time both mags produced drops of 300 rpm. Bugger!
The whole point of the mag drop check (as I understand it) is to make sure that the spark plug connected to the magneto is firing properly, and also that the engine would continue to function in the event of losing a mag in flight. So it's best not to risk things....however frustrating they may be.
Ah well, best to be down here and so on and so forth. Besides, the weather soon rolled in, and how. Anyway, the aeronautical topics of pleasant conversation in the clubhouse were worth the journey anyway. And I re-booked again, of course!
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So back at Old Sarum again for more taildragger training, this time with almost zero wind. Also….Santa turned up (in an aircraft)! As there was a Christmas do in the clubhouse, Santa was flown in via Bulldog, with his bag full of presents. After a quick circuit, beginning from a discreet part of the field, he arrived next to the clubhouse, got out with his bag & distributed the goodies! The children were very impressed. Although I at first didn’t know this was going to happen, and entertained the notion that I might be hallucinating, but my instructor set me straight.
As today’s flying consisted solely of circuits, the day’s training broadly resembled last time, with a few minor differences & improvements, with the major exception of my takeoff execution…For some reason as the day wore on, my technique increasingly resembled hard runway technique; that it to say when I was at flying speed, I merely hauled the aircraft off the strip (i.e. rotating at the appropriate speed); this provoked a) poor performance b) choice words from the back!
The correct technique, as patiently explained to me post-takeoff, is to lift the tailwheel, and then when the aircraft becomes buoyant (Were I not wary of using possibly clichéd phrases, I would have typed “when she’s ready to fly” there) gently lift off into ground effect, thus providing more acceleration (all the way to the best climb speed in fact, whilst still flying down the runway in GE) without the friction caused main gear/ground contact.
In fact – now as I type this I remember being taught this before! Strangely enough during my initial PPL training in the US, I was taught more or less the same method, except that this was taught for use as a shortfield takeoff technique. Whereas this applies all the time to the Cub on grass runways, I would assume. At this time of year the extra friction caused by grass strips (although Old Sarum is quite good for runway drainage, due to the geology of the local area) has the potential to slow aircraft down somewhat….plus flying down the airstrip in ground effect a few feet off the grass is quite fun.
Today the instructor also got me to fly a very steep powered approach, but not a glide approach. I was slow in adapting to this – initially I was consistently high or fast or both on the approach, but seemed to get used to this. Compared to last week (where I thought I was doing quite well!) it was a much steeper descent. This was eventually fine – save for the final 50ft or so! I got this licked by the end. At which point I decided to quit whilst I was ahead, ending on a high. The next time I’m back I shall be aiming to go solo by the end of the session. Back to Top
Second taildragger slot today at Old Sarum. As before, the first part of the lesson would be ground work; in this case high-speed taxis up and down the runway, accelerating to takeoff speed, lifting the tail up & then decelerating before actually leaving the ground. This teaches control of the aircraft at high ground speeds.
On my first try at this yesterday I didn’t do too badly; however today the crosswind component was more significant (the max demo’d crosswind limit in the Cub is 10kt) so I expected a harder time of it. I was right! I didn’t do too badly however, and after about 30min of ground practice I flew (increasingly on my own) 1 hour of circuits. I ended up re-learning the wing-down technique and a lot of small other points. However overall I was pleased with my progress, and so was my ex-RAF instructor. If he said it was satisfactory progress, then that’s good enough for me.
The high speed taxi runs (with a few more “wobbles” in them than yesterday) really brought home the importance of using rudder on the takeoff/landing runs – if you don’t correct immediately with rudder for any yaw that develops, the aircraft will swiftly leave the centerline. I was also taught to use reference points to either side of the nose, as you cannot see the end of the runway until you lift up the tail.
Also the importance of carb heat was again impressed on me – we used it continuously on the ground, and for the entire downwind & base leg in the circuit. The use of trim was also different – as opposed to a wheel, there was a handle you wind in a circular direction, very similar to old car window handles, mounted on the side of the cockpit. I actually found this a lot easier to use & trim effectively than the other system.
I also learned about the two types of landing – 3-pointers or wheelers. The former is the normal, preferred method – touching down in a nose up attitude so that all 3 wheels touch down at the same time, or maybe with the tailwheel slightly before the mains. The latter is used in crosswinds – touching down on the mainwheels and then lowering the nose, so as to present a flat surface to the crosswind rather than a high AoA one.
All in all a lot of hard work but fun too! I’ve booked a number of slots over the festive season – if past weather is anything to go by, I should get to fly at least one of them. I’m also hoping to do some hourbuilding on the PA-18 – don’t laugh – as it’s a fun aircraft to fly, more classier than your average spamcan in my opionon, will certainly improve landing skills, and is also cheaper than most. On the downside of course, there is a higher potential for accidents, less avionics to help you aviate & navigate (and communicate, but the radio is being re-installed I understand) and a less than average useful load/range.
But still it’s fun! Beats the pants off the Cessna 152….
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Today: Conversion course on the PA-18-135, based at Old Sarum, near Salisbury. Since this was now the 4th time I’ve booked a Tailwheel conversion at Old Sarum Flying Club, I was somewhat gratified that the conditions today were suitable, if not perfect. I must stress however the previous 3 times were cancelled to weather, not the club! In fact on one previous occasion I received groundschool instruction & taxiing practice, and then the weather closed in. Despite this, I wasn’t charged for about an hour of groundschool & use of the Cub for about 30 minutes on the ground.
Previously I’ve managed to get up to taxing up and down the airfield (which for the uninitiated is harder that it sounds on a tailwheel aircraft, especially given a nosewheel background & a fair crosswind). This is due to the fact that the nosewheel arrangement is stable in the turns, whereas the taildragger, plus the decreased visibility over the nose, added to the tendency for taildraggers to tip over nose first if too much brake is used, with a little bit of lag in the turns when using rudder….adds up to a much needed 5hr course before nosewheel PPL holders can be signed off to fly taildraggers. Most of this involves ground handling plus takeoffs and landings, as well as learning to taxi properly.
By taxiing properly I mean the need to keep the stick in the proper position to avoid being caught by the wind (this is more of an issue with taildraggers due to the higher angle of attack the surfaces are at on the ground) and weaving due to the poor visibility over the nose. This is in addition to the need to mind where exactly you are dragging your tail…During said takeoff runs & landings, any yaw must be quickly checked with rudder, or, due to the instability inherent in the taildragger configuration the aircraft will quickly try to swop nose for tail, ending in a groundloop. Depending on the speed/wind/etc this can either end in merely a bruised ego, or a complete writeoff.
Keeping clear of any potential groundloops requires steady, quick rudder control inputs to keep on the runway centreline; in addition to yaw from propeller torque & slipstream effect, taildraggers are also affected by gyroscopic precession & asymmetric blade effect. The former is where upon rotation the spinning disc of the propeller acts as a gyroscope & resists movement, thus producing a precession force to the left or right. The latter is where the downgoing propeller blade produces a different amount of lift from the upgoing blade, due to the nose-up attitude of the aircraft on the ground. Wind & pilot error (!) also affects the path of the aircraft.
The sum of all these effects, for an aircraft with a clockwise rotating prop, is for the aircraft to yaw mainly to the left, and the amount of yaw depends on power, wind & whether or not the aircraft has it’s tail on the ground, or is at the point in the ground roll where the tail has been lifted up to assume the horizontal attitude. This yaw requires a lot of rudder work by the pilot (trust me) to prevent the aircraft veering off course, which if left unchecked will rapidly produce undesirable results. This is also true during the landing run.
So, with all this in mind (especially the part about how to avoid embarrassing, or worse, groundloops and/or taxiing mishaps) after a quick refresher session of ground training, a walkaround the aircraft (which was incidentally missing it’s radio. This was not an issue, as we were only going to be in the circuit & on the ground) I proceeded to weave my way up & down the field. After adjusting my weave rate, and allowing more for the lag in the rudder pedals on the ground, my instructor pronounced himself satisfied with my progress so far. We therefore went round for a quick circuit before the weather closed in.
Overall impressions of the aircraft; a rugged, solidly built aircraft with simple avionics, which comprised ASI (in mph) compass, altimeter, RPM gauge, turn & slip, balance ball, oil Ts & Ps, alternator output & visual fuel gauges (i.e. float gauges built into the wing root, visible from the cockpit). No DI, no radio navaids, no stall warner, no VSI, no radio & no transponder!
The engine was also prone to carb icing, and also idled in a way which seemed (to me) that suggested that it was about to cut out. However my instructor assured me this was not the case and it didn’t, so there you go. Visibility was OK – better than most high wings such as Cessnas due to the roof cut-out panels, which were quite useful when turning. There were two bars in a V shape between the panel coaming & the front canopy; however these didn’t obstruct my vision noticeably.
Slow flight & stalling was relatively straightforward, the only proviso being to pay good attention to the balance ball. In fact the only thing I didn’t like was getting into the aircraft! The single step is set a fair distance back along the fuselage from the front seat; consequently getting in involves contorting your legs around the bracing, seat and stick to slide into place. Getting out also requires a spotter or luck to help you place your outgoing leg back onto the step safely. 30 December 06 - Supercub Magnetos
17 December 06 - The Supercub, Santa, & Steep Powered Approaches
10 December 06 - Further Supercub Training
09 December 06 - PA-18-135...At Last