Archive for the General Flight Category

Flying in California

Friday, June 1st, 2012 | Permalink

Before I started learning to fly, I’d go on holiday and do typical holiday excursion things.   Since starting to learn to fly – I’ve found myself looking almost permanently upwards (or at least once outside of LA).

This trip was to tour LA, Palm Springs, San Francisco and then drive back down the coast road via Santa Barbra back to LA.

Palm Springs – Blue Skies

Palm Springs and Blue Skies

Blue Sky over Palm Springs

I didn’t really think through the idea of going flying in the states before leaving, but once we hit Palm Springs, with its seemingly infinite blue skies – time to start emailing local flight instructors who could get me up there!

Having left it late to start asking around and with limited time, it was never going to be easy – Palm Springs was a no go, instructors were busy or I was busy.   Shame, I have to go back there to do some flying, you can’t imagine the vastness of the blue cloudless skies until you really experience it.   I’ve developed a new appreciation of deserts 🙂

San Francisco

It rains in the UK and they say we like nothing more then to talk about the weather, or at least I thought it rained in the UK.  Not like it does in San Francisco!!

At about 5am it must have started raining, not drizzle, the real deal full on soaking rain.  We were out doing tourist stuff all day and it didn’t let up until maybe gone 10pm – normally you get gaps, clearly when it wants to rain in San Francisco, it just rains!

The next day with the last of my emails to local flight instructors drawing blank and the weather not looking to improve.   I decided we should be spontaneous, hire a car for the day and just drive up to Napa and see what we find.

Over breakfast my wife found an advert for a vintage aircraft company.  Great we’ll aim for that and if it doesn’t pan out, we’ll be in Napa the weather was set to be good and we’d go try some wine – life could be worse 🙂

We found it easy enough, but pulling into the small airfield car park things didn’t look very promising.   There were no cars in the car park for a start and the place that looked to be the premises of ‘Vintage Aircraft Co.’ looked pretty silent.   After a stroll over to confirm nobody was home, it was back in the SUV to see if a last, slightly desperate attempt to give them a call yielded any success.

As the phone just rang out continuously and I began to accept fate, a camper van came out of the main hanger area of the airfield and pulled up alongside us.

“Hey, how’s it going……if you’re looking for…..I think they’ve packed up for the day”

“Oh really, I was hoping to go flying – I’m learning in the UK.”

“Wanna to see some cool stuff?? ………follow me.”

I had no idea who this guy was, but the offer of seeing some “cool stuff” sounded to tempting to pass up – especially as the hope of getting up in the air had just been shot down.

He spun his camper round and headed back into the airfield, we did similar and followed him up to the hangers.

At this point, when he was about to pull back the doors to the hanger I had expectations of seeing his plane, maybe it was a C172 he was proud of, or maybe something a bit more expensive like an SR22, or perhaps older like a Tiger Moth.

What I didn’t expect to see, was a replica, 1909 Bleriot!   But that’s what he had….

1909 Bleriot XI

1909 Bleriot XI

Ticks the box for something cool, especially as he built it in 29 days!   It turned out that I was talking to Eric Presten.   He’s got all the right stamps of approval for building and flying such stuff and probably best known for publishing Vintage Flyers photo book of almost every old and cool plane that has ever taken to the air.   It cost me the price of the book, but I did get my copy signed 🙂

Next to the Bleriot (see it run up its engine here) was his Cessna 182, sorry no pictures of that, Google has enough already if you want to see one.

The tour didn’t stop there though, following a motion of did I want to see some more cool stuff, we closed the hanger doors and headed off on foot round the corner.

As the hanger door opened a very shiny plane stood before me (1928, Stearman).

Stearman Fury

Stearman Fury, 1928

Ok, I hadn’t managed to get into the air, but this was turning out to be a pretty successful day none the less and Eric was a really nice guy to chat to about all things planes.

As he was closing up, I figured it was worth a punt and asked if he knew anyone in the area that might be able to get me up in the air today…..

“Oh yeah sure, follow me….”

We jumped in the SUV, drove out of the small (by UK standards, pretty random) airfield and up the road for about 3-6 miles – to yet another small, slightly random airfield.

Eric was telling me that there was a flight school here so there should be no problem getting up in a C172.   Great, I fly those here, so things were looking very much up.

The next thing I remember hearing was:   “Hey, Bob’s in town….”

I’m sure this was meant to mean something, of course Bob, everyone knows Bob.   Don’t they?

When the next sentence was “…..and he has a bi-plane.”   Bob quickly became someone I needed to know 🙂

It turned out that Bob didn’t just have any old bi-plane, he had a 1926 Travel Air 4000.   Believed to basically be the last one of its kind flying.

Travel Air 4000 (1926)

Travel Air 4000 (1926)

I was now presented with options and a bit of a dilemma.

Either go flying in a C172, which you can do pretty much anywhere and I do basically every other weekend or so – but get to fly the plane.

Or go up in a 1926 Travel Air 4000, last of its kind, very cool plane, probably once in a life time – but only get into the sky as a passenger.

Not that tough a decision, once in a life time Vs every other weekend…… It had to be a spin up in the Travel Air!

We did a deal with Bob, in his words “I like flying, not business….”   so I think we covered his costs of flying the plane and made him a bit of cash for the day – but we got a deal way better than what you’d get if you did an air tour in San Francisco (usually also sharing the experience with 6 others etc.)

View of Napa from a Travel Air 4000

View of Napa from a Travel Air 4000

Bob flew us out almost to the coast, over the wine valley’s and along the hills – we flew pretty low, if we were higher than 1200ft I’d be amazed. It was a really, really good trip up and the views were well, the only way to see Napa to be honest.   On the return leg he decided to have a bit of fun with it, pulled back on the stick and we were aiming for the gods…….before cutting the throttle yawing the plane 180 degrees to point back at the ground and then into a dive.   Brilliant!!   Bi-planes, fly slow and this maneuver in them always looks like (from the ground) they’re turning almost on the spot, mid-air.   To make sure we got our moneys worth, he did it again 🙂

Aviation People are Great People

Since I started learning to fly, I’ve met a lot of people who fly or are learning to fly.   It never ceases to amaze me how much they all seem to be willing to help you out, show you something cool they’ve got, take you 6 miles up the road to find someone who can take you flying or just buy you a beer.

I can’t thank Eric and Bob enough for helping sorting this trip out, it was just fantastic.

…….and the last thing to put a smile on my face.   When we landed, I was chatting to the guy who ran the flight school there, asking how much it cost.   $139/hour with an instructor!    Just to put that in perspective, it costs me £179/hour.    It makes the idea of going out there for 1-2 weeks and just building a stack of flight hours very tempting.

Happy new year!

Sunday, January 1st, 2012 | Permalink

Happy flying in 2012……

Revisiting Flaps

Saturday, September 3rd, 2011 | Permalink

In the previous post I made a correlation between lift and pitch, it’s been bugging me because it was a bit loose and there is a lot more to it, so perhaps an elaboration of the bullet points is in order.

A plane has a number of forces acting upon it.

Cue a diagram:

Cessna Centre of Gravity Forces

Aeroplane Forces

The position of the Centre of Gravity is key and any given aeroplane will have defined limits on how far forward or rearward it can be (outside of which the plane is illegal to fly!).

The reason for this is that the position of the Centre of Gravity impacts planes stability in pitch.   This is because the distance between the Centre of Gravity and the planes stabaliser  (seen above creating lift or downforce), defines the leverage the stabaliser has.

If the distance is very long (centre of gravity is very far forward), then the plane will be very stable in pitch.   However, too stable and the pilot will have no control of the plane.

If the distance is very short (centre of gravity very rearwards), then the plane will be unstable – highly manoeuvrable, but in the extreme it will make the plane tail heavy and the pilot will not be able to stop the plane from wanting to pitch nose up.

So using the diagram above, if the downforce generated by the stabliser increases and overcomes weight the plane will start to pitch nose up.   If the stabaliser starts to generate lift, the plane pitches nose down.

There is a couple around the CofG for thrust and drag, if thrust increases considerably this to will make the plane pitch up……but this is due to a secondary effect.  Increasing thrust will impact the lift/downforce forces – and they will dictate pitch.   Thrust/Drag alone do not make an object change its pitch, you can think of a plane as a car at this point…..but add wings to a car and it becomes a plane because now you have lift & downforce which will either push the thing into the ground or make it take off.

Pitch of an airplane is dictated by its centre of gravity and the forces acting forward or aft in a vertical direction around that lever.

Balance Lever

Balance Lever

If the net forces acting down on the right of the lever is greater than the net forces acting down on the left of the lever……the plane will be pitched nose up.   If it’s reversed, the plane will pitch nose down.

The first diagram shows that if extending flaps to 10 degrees just increased lift, the plane would pitch nose down – as it would pivot around the centre of gravity.  The fact the plane (high wing designs) doesn’t do this, tells us that the extended flap is also having an effect on the forces generated by the stabaliser, which is outweighing lift/weight pivot.

So what’s going on?

The extended flap changes the shape of the wing, this changes the airflow off the wings trailing edge.  On a high wing aeroplane design like on a Cessna, this  increases the downwash striking the stabaliser.   In turn this means the stabaliser generates more downforce.

We’re now back at the balance lever diagram, the increased downforce outweighs the lift/weight couple and causes the plane to pitch nose up.

Pitching nose up causes speed to reduce, reducing lift, causing the plane to pitch down and hey presto the plane is oscillating – until it balances itself out.

Most of the above has explained high wing designs, for low wing designs like the Piper Cherokee the principles are the same but the plane will pitch nose down.   This is because in low wing designs the main wing and the stabaliser are roughly level, so now changing the shape by extending flaps causes less downwash to strike the stabaliser.   The lift/weight couple has more effect because the stabalisers ability to produce lift is reduced.

Sennheiser Vs David Clark: Sennheiser Wins.

Friday, August 26th, 2011 | Permalink

Sennheiser HME-110 Side view

Sennheiser HME-110 Side view

They say the pub quiz rule is:

If in doubt, go with your instincts!

In the end that’s what I did to end the dilemma. My brain refused to accept that it could be possible anyone on this planet makes a better headset, at any relative level, than Sennheiser do.  So I bought myself a set of the HME-110.

A few people online recommended getting the replacement gel ear pads, so rather than risk having to pay postage twice, I thought I’d get some of those as well.

Today was my first flight using them (after many cancelled lessons due to rain!).

Verdict: The HME-110 is Absolutely stunning!

Anyone who reads my original post about the dilemma, go with all my pro’s…….forget any worries I had, they’re all nonsense.

Sennheiser HME-110 Special Edition Top View

Sennheiser HME-110 Top View

The weight difference is huge!

The HME-110’s are blissfully lightweight, yet feel rock solid in construction. In terms of weight I totally forgot I had them on in my flight.

Noise Reduction is fantastic and they don’t crush you’re head to achieve it either. I found the standard ear pads to be good, but I’m glad I got the gel one’s. Fit those and it’s another level of comfort. Add the gel ear pads to your order and you’ll still pay less than a set of H10-13.4.

I’d recommend them because they weigh so little and their noise reduction is excellent…….but why I’d really recommend them is because their sound reproduction is superb, I mean truly clear.

They are never going to match a set of studio monitors, let’s be honest about that, they’re impedance matched for an aircraft system so you won’t get the same raw volume if you tried. But in terms of frequency response, I’d believe the figures on the box any day, I tried them using some separate kit and their top and bottom end frequency response is sooo very good.

My worries about Microphone Boom Arm Radius:

Forget them, you can’t notice the boom arm in flight at all. It’s really just an optical illusion to some extent, once you’ve got them on, they’re lightweight the mic has enough reach to be perfectly positioned and the rest of the arm is outside your field of vision.

If you’re worrying about that boom arm, believe me, forget your worry just buy a set and when it arrives trust me you’ll go “What was I worrying about! How good are these!!”

Is it safe to fly in a General Aviation aircraft?

Sunday, August 21st, 2011 | Permalink

The probability of being in a fatal airline accident is ridiculously small, so small in fact that if you make it to the airport, the odds are well in your favour you’ll get to your destination airport (The chances you won’t are around 0.5 x 10^-6)*.

Airliners have lots and lots (and lots!) of redundancy in their systems and propulsion though, so you’d expect that even if they suffer a single failure, they could ride it out and land safely somewhere……..General Aviation aircraft, particularly your typical Cessna style Single Engine Piston powered machine, have somewhat less layers of redundancy (the lack of a second engine being the obvious one!).

Next to pilot error, engine failure is going to be the most likely cause of an emergency / accident.   It’s about 0.00315789% probable of occurring* (2006-2007 it happened just 24 times for 760,000 hours flown by GA aircraft, 4 of which were on the ground).

As a result, the rules for how low you can fly come from Rule 5 of the ‘Rules of the Air’, it’s goal is to ensure pilots are flying high enough at all times such that should they suffer an engine failure, the pilot has enough altitude to make an emergency landing without endangering those on the ground.

It defines three key provisions:

  1. 500ft :  An aircraft must not fly closer than 500ft to any person, vessel, vehicle or structure.
  2. 1000ft: When flying over the congested area of any city, town or settlement, an aircraft must fly high enough to land clear of the area without damage to people and property on the surface should an engine fail.  OR fly not less than 1000ft above the highest fixed object within 600m of the aircraft – whichever is higher.
  3. 1000 People:  When flying over an organised open air assembly of more than 1000 people, the aircraft must fly high enough to land clear of the assembly without danger to people and property on the surface should the engine fail.  OR fly not less than 1000ft above the assembly – whichever is higher

So how safe is it to fly in a single engine piston class general aviation aircraft?   EASA (European Aviation Safety Agency), have done some risk assessment work.

They found that the fatal accident rate in a single engine general aviation aircraft caused by engine failure, was 0.66 x 10^-6 per flight hour (0.00000066).    So statistically, you’d have to fly a little over 1.5 million hours before the accident would occur……I’m willing to bet most non-instructor GA pilots in the UK don’t clock more than 100 hours per year, so statistically it’s still an unbelievably safe way to travel.

* EASA Risk Assessment Report

Red Arrows Pilot Killed

Saturday, August 20th, 2011 | Permalink

This story was just breaking as I left for my subsequently cancelled lesson.   We had it on the TV at the aero club while waiting for the rain to clear.

The amateur video footage made me think it was highly unlikely anyone could have got out – but one of the guys there seemed to know more suggesting he’d ejected, a ray of hope at the time.

Sadly it has now been confirmed that the pilot (Flt Lt Jon Egging) died in the crash.

I’m no expert, but from the footage I find it hard to believe it could have been anything but a mechanical failure of the plane.   The pilot is unquestionably one of the best in the business.

All thoughts are with him and his family.

Headset Dilemma (Sennheiser Vs David Clark)

Wednesday, August 17th, 2011 | Permalink

Normally if you asked me about headsets, I’d tell you go directly to Sennheiser, when it comes to closed monitoring of sound, they’re the best.   Use a pair of HD-25’s and any definition you had of a good set of headphones for monitoring sound (particularly with VERY HIGH background noise) will be shattered.

If you look at commercial aviation (airliners), you can see much of the HD-25 in Sennheisers’ range of commercial aviation headsets (e.g. HMEC 26).

When it comes to General Aviation, I’ll admit to being a bit shocked.   At the General Aviation level, David Clark is pretty much the standard.

I’ve worn them, I’ve looked at their technical details  and generally done what I guess a lot of first time aviation headset buying people will go through:  Spending a lot of time trying to work out which way to go.

As you’d expect online lots of people have very polar views on who is best and why….but it’s vaguely fair to say the H10-13.4 or H10-60 are the Passive favourites of the David Clark camp.   For Sennheiser it’s the HME 110.

The HME 110 is the same as the 100, the difference is simply:  Black caps, softer pads and the head cushion has been made softer – so technically the same thing, but for the black caps alone I’m ignoring the HME 100’s.

David Clark:  The Pro’s.

  1. Largely the Industry Standard
  2. More compact design relative to the HME 110, with emphasis on the radius of the microphone arm is on & the size of the mic. wind screen
  3. A military product look of robustness.

…and to be honest, then I start to struggle.

Sennheiser: The Pro’s

  1. Arguably slightly better Noise Reduction Rating 24dB [David Clarks: 22-23dB]
  2. Much better headphone frequency response range (45 – 15,000Hz) [David Clarks typical response range of 200-5,500Hz]
  3. Better Microphone response range (200-5,500Hz) [David Clarks (H10-13.4) is 300Hz–3.5KHz]
  4. Lower Weight (350g), roughly 25% less than the David Clark models [DC’s 10-60: 623 grams / H10-13.4: 467 grams]
  5. Warranty…….I’ve heard a lot of people talk about spare parts for David Clarks, true.   Sennheiser’s response would appear to be:  “Spare parts?  You won’t be needing those, have a 10 year warranty on us”).

Human speech is 60-7,000Hz range, as such for best reproduction you want something that has a frequency response at least twice this range (Can you see where Sennheiser is going with it’s frequency responses yet).   Anything that can’t respond to this range will be dependant on picking up the harmonics of the original frequency…….so in theory if you put out a sound around 60Hz, the DC’s will only pickup the 4th harmonic of that sound.

That’s the theory anyway, I have v.good hearing – how good it is at top and low end frequencies while a Cessna’s engine is roaring in the background is another question.

Sennheiser size

I think the best video of the HME 110 in use I’ve seen is this, you can see what I mean about the radius of the mic boom arm, relative to other headsets.

The last bit is my only concern, but having watched a few other videos (and also the fact it’s not stopping the above video user operate  a massive camera), I’m starting to be less worried.

Other videos of Sennheiser & DC’s in use

HME 110, side view in use.

HME 110 & DC’s in use in the same plane

HME 400 or 460 and David Clarks in use in same plane

……next lesson is in a couple of days, so I’m gonna have to resolve this dilemma pretty soon and order one or the other!

The Extra 200 that didn’t want to fly.

Sunday, August 7th, 2011 | Permalink

The Extra 200 that did not want to start its engine!First flying lesson done and with my externals lesson on the horizon, this weekend it was all lined up to be a “fun flight” in an Extra 200 – somewhere between clocking up a bit more time in the air and just having fun doing some aerobatics.

Upon arrival to the airport I’d watched the Extra 200 land, blue skies and good visibility – the gods were seemingly being kind to us today.

Pre-flight briefings done, flight suit on, headset plugged in and canopy closed we were ready to go…….

That is we were ready to go, in the 20 minutes since it had landed the Extra had decided it was less happy about going back up.   The “Oh…” from the instructor in the back seat was a give away sound of ‘Hmmm the engine hasn’t started and this is not looking promising.’

While my instructor assured me the battery was not flat, as far as the Extra was concerned it was flat – perhaps a stuck solenoid was the running theory.  My instructor made calls to various people and tried a few things to bring it back to life, but there’s a limit to what you can do before you start needing CAA aviation mechanic approvals and we were reaching that point quickly.

So sadly, it was so close but not to be (at least not today).

Re-booked and my instructor pointed out that the silver lining to this story is that in a few weeks I’ll have had more lessons under my belt, some if not all of them with him, so when I next get to try the Extra I should be in a better place and be trusted to do a bit more with it!