Jump to content
Touring Motor Gliders Association (TMGA)

Most Excellent Wave Flight by Jim Lee


Recommended Posts

  • Registered
Eric Greenwell

Jim Lee flew his Phoenix out of Minden for a 500k wave flight yesterday (Nov 4). Check it out on the OLC, download the IGC to SKysight, select the 5K Wave parameter, and see the almost perfect jutaxposition of trace and wave lift (also in the attached image). I hope Jim will describe it a bit, and tell us if there was any problem starting the engine after a four hour flight at 18K.

Jim lee wave flight on Skysight.jpg

Link to post
Share on other sites
  • Registered
Eric Greenwell

I'm also wondering which wing tips he used, and if the ground winds (which can be severe at Minden during wave) were a problem. I often use the short tips for winter wave flying out RLD (Richland, WA), as the ground winds can be mild at the start of the flight, but can increase substantially as the day progresses.

Link to post
Share on other sites
  • 2 weeks later...
Jim Lee

Thanks Eric.  Long wings (for soaring - always!), normal small tires with wheel covers.  All seams taped, including cowlings, gear legs, wheel covers, drain holes, and wingtips. 

I almost always wait until descent to 2000'agl to let the air warm the engine before starting.  We also descend slowly without spoilers to be kind to the gel coat.  Best for plane and engine to warm up in the lower altitudes slowly.  I orbit the airport and wait for 120 degrees oil temp so that if I need to go around in the sporting conditions, the engine is ready to perform.  As I orbit the airport at 800-1000agl, I watch the windsock carefully and pick the best opportunity to land, then full spoilers and get it on final asap.  Minimum spoiler for 3 point touchdown, then full spoiler to keep it on the ground.  Sometimes I have had to wait over 30 minutes for the right conditions to land.  I am prepared to fly to another airport or land on a taxiway for better wind direction if forced.

I once started the mighty Rotax at 16,000msl over Bishop after a super wave day.  The engine started fine, but coughed, sputtered, shook, and told me never to do that again.  It took a very long time to warm up and it had to be bad for the engine, so I will never do that again.

My Phoenix has a car battery for long soaring flights and the smaller back up rear battery is always fully charged.  Have never had a problem starting the engine.

We had Skysight in the cockpit via Galaxy Note 4.  Only an Android phone will cache the images in flight without internet, the iPhone won't do it.  Skysight is scary accurate for wave forecasts, I don't know how they do that.

Last year the Phoenix and I were 1st in the World in OLC speed points such that this year the DAeC/OLC has increased the handicap by 32%, by far the largest sledgehammer handicap adjustment ever issued to any glider!  I guarantee you that they did not do any flight testing, just looked at the scores and said we have to do something about that Phoenix.

Champion Speed-OLC 2021 - Worldwide (onlinecontest.org)

Link to post
Share on other sites
  • Registered
Eric Greenwell

I only tape the wing root and tail junctions, just because there is so much stuff hanging out, I imagine the taping improvement is tiny, but I've never tried to measure the improvement.

I usually leave the engine running in winter wave, as it seems be some heat from it leaks in, even though it's idling at about at only 2400rpm/60 knots. The "full coverage" cowl flap really helps in the winter.

I extend the spoilers progressively on short final, so I have full spoiler just after flaring, hold it off until it's in a three point attitude, and just let it settle down. Full spoiler early gets it on the ground quicker, and there is less chance of bouncing or wind effect. The attitude is the most important, of course: it doesn't balloon if all three wheels touch at the same time, or if the tail wheel touches first. This technique works well with short or long tips.

Skysight would be nice in the cockpit, but my old ClearNav doesn't support it. I should find a way to get Skysight while flying. What program do you use on the Galaxy Note 4 to get Skysight, and do cache them on the ground? Can you get them in the air? I have an old Galaxy 5 that might work.

Don't take all the blame for the OLC handicap upgrade! They probably also took a look at some of Doug Levy's flights and said "We must fix that handicap!" It looked like you might still have been #1, even with the higher handicap.

Link to post
Share on other sites
Jim Lee

Eric, running any engine at idle is typically bad for the engine, with carbon buildups, fouling, incomplete combustion, and water not being burned off in the oil.  You should get a large battery and not be afraid to shut down the engine.  If you must run at idle, be sure to keep the oil temp as high as possible, 190 degrees will do it.

Your landing technique is fine.  However, for really challenging conditions with strong winds such as found in wave conditions, some things need to change.  The less spoiler that is used, the lower the stall speed.  In ground effect with less than 1/3 spoiler, the stall speed is 35kts.  After I touch down and go to full spoiler, the stall speed goes to 40kts, which gives me a 5kt buffer on getting gusted back into the air.  If you touch down with full spoilers, there is no buffer, and the plane is more easily gusted back into the air.  Getting the plane on the ground quicker should not be a goal.  There is always plenty of runway, and the goal is to keep it off the ground as long as possible, and touch down with the least amount of airspeed, and then quickly go to full spoiler to keep it on the ground.

Matthew Scutter of Skysight just posted this email to another Phoenix owner:

"I'm not able to control what your phone retains unfortunately, it's a limitation of being a web app rather than a 'real' app - we get intentionally crippled by Apple / Google, as they want us to make 'real' apps in their stores and give them 30% of revenue. I tell your device it to cache everything you click download on for 24 hours, but it decides of its own volition what it keeps and what it clears out. I don't advertise the feature too widely due to the variety in experience outside my control.

 
Not setting flight mode doesn't wipe anything, but your phone sits there for a very long time trying to download new maps before giving up and resorting to the saved ones.
 
What appears to help is:
1) Having lots of free storage space on your device - if it starts running low your phone starts deleting website storage
2) Using Chrome rather than other inbuilt browsers
3) Only downloading the minimum charts you need
4) Downloading the most important charts last
 
Some devices behave better than others.
 
One day I may have to end up making an app. The antitrust lawsuits are gathering steam so the App store fees are getting lower, but they might also just open up what they let websites do too..."
 
I use the Galaxy Note 4 because it is a large size, but other Galaxy (android) phones should work as well.  There are some tricks involved to fool the phone.
1)Select the little spinner button to load 10k altitude.
2)Do the same thing with 13k and 16k.
3)Double click the center phone button to "pause" Skysight.  Don't push the back button!
4)Go to settings and select airplane mode so Skysight won't try to reload when you return.  
5)Doubleclick the center button to pause settings.  Don't push the back button!
6)Select Skysight again on the home screen to return to the cached wave profiles.
7)You can push the side button to turn off the screen, or you can let it go to sleep if you are not needing Skysight at the moment.
8)Always push the side button or doubleclick the lower center button to return to Skysight, but never push the back button.  If you do, the phone will try to reconnect with Skysight online, and you will lose the cached data.
Link to post
Share on other sites
  • Registered
Eric Greenwell

I looked into the idling question several years ago, and concluded the harm to the engine was very minor at worst. I do keep the oil temperature at 190F while idling; the CHT temperatures also stay in the mid-range. I'd prefer to shut the engine off (it does glide better), but since I don't want to attempt a restart without being in gliding range of an airport, our typical weather and airport situation means I'm frequently heading to an airport to do a restart. It really diminishes the joy soaring, when a lot of the time is spent that way, so I've chosen to enjoy the soaring more and accept the additional maintenance (which has been small) for the engine.

I forgot to mention that I land in -4 flap in windy or gusty conditions, so I can touch down at a higher speed. That gives me better aerodynamic control during the flare, and makes the plane less sensitive to gusts once it's on the ground.

I'm not sure the stall speed varies significantly between 1/4 and full spoiler, but I plan to fly today, so I'll do some experimenting. If it does change as much as you say, your landing method would probably be better. The advantage of getting it the ground ASAP is spending less time close to ground, fighting the gusts.

Thanks for the info on using Skysight. I do have a Galaxy S5 phone just sitting around that will probably work as you described, so now I'm waiting for a new battery, as the old one runs only 20 minutes.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...