Getting a Self-Launching Sailplane?
Congratulations, but please fly safely!
by Bob Moore
Bob Moore has a DG-500M on order from DG and is one of the most experienced self-launching pilots in the USA.
This article was published in the ASA-Newsletter first.
I am an enthusiast for self launch!
I bought one of the first PIK2OE's to come into this country, and have now flown it for some 2500 hours (250 hours on the engine). Thanks to self launch independence from tow planes and tow pilots, I have been able to do a lot more soaring than I could have otherwise. And because of restart capability, I have been able to make almost every flight a cross country flight, knowing that I would get back and wouldn't put friends or family to a lot of inconvenience should I land out. All of this is great, but there are factors associated with a SLS (Self-Launching Sailplane) that pilots should be aware of. One might think that with an engine, SLS's would be a lot safer than "pure" sailplanes, and that they would have a lower accident rate. It isn't so! Repair stations report that they have a lot of SLS's in their shops for major repair. I applaud your getting an SLS, but feel impelled to share with you a few of the things I think I have learned along the way.
Engine Failure:
In the beginning, I vaguely assumed that engine failure-on-take-off would be no more serious than a rope break when launching a conventional sailplane. I also assumed that it was unlikely to ever happen to me. I was very wrong on both counts! Engine failure on take off with an SLS is serious. There are several reasons it is more serious than a rope break: The motorglider is heavier than a conventional sailplane, more like a competition glider with a full load of water ballast. And, the extended engine and wind milling propeller cause tremendous drag. In the PIK, the glide ratio drops from a claimed 40 to only 14 - about like a primary glider, or an airplane. There is also fuel on board, which can burn. So, engine failure on takeoff deserves a lot of respect. It certainly gets a pilot's full attention when it happens! How likely is it to happen? I don't know, however I have had this experience five times in my PIK, and twice with the Hummingbird. Two-cycle engines seem inherently less reliable than four-cycle, and most probably don't get the routine maintenance as they deserve.
What to do if the engine fails on take off?
At a motorglider safety session at an SSA Convention not long after I purchased my PIK, Captain Tug Willson (probably the World's most experienced motorglider pilot) gave us some emphatic directions. Tug said that we should immediately do a maneuver that could be described as "the last half of an outside loop", while simultaneously dropping the gear, extending the flaps, and opening the dive brakes. If there is any runway left, land on it! If not, take what is straight ahead. Don't try to turn back unless you are already plenty high. Tug's advice has saved me several times. After one such experience, I consulted a former military pilot friend. I had been sucking up the gear smartly right after lift off (just like the big boys), and throttle back to climb power shortly thereafter, and would simultaneously switch off the electric fuel pump - recommended in the flight manual to reduce fuel consumption (there is also a mechanical fuel pump). My friend said that an aircraft engine is most likely to fail when the pilot changes some setting. I now use maximum takeoff RPM till I near 1000 feet AGL, and then turn the electric fuel pump OFF.
I also leave the gear down till then - one fewer thing to possibly forget if there is an emergency. I also learned, early in the game, that the plugs in a two-cycle engine can "load up" easily - the day I learned this I had to taxi a long way (because of an unusual wind direction at Ephrata) and then hold a long time for other traffic. As I crossed the end of the runway, the engine faltered. I got it going again (there was no place ahead to land). I replaced the plugs and the fuel filter, and cleaned the breaker points. I now install new plugs every 8 hours of engine time (plugs are cheap!).
How high is high enough?
Remember that aircraft configured like the PIK , DG400, DG-505 and other retractable engine sailplanes there is lots of drag if the engine quits and you will come down rather quickly. After shutting off your engine (at a safe height) and before retracting it, you may want to experiment to see how much altitude you would lose turning back to the field. Remember if you are operating from a runway rather than from a large grassy field - you need to allow for more than just a 180 degree turn, actually for 360 degrees of turning. 180 degrees will put you alongside and parallel to the runway, and another 90 degrees will put you perpendicular to it. You then have to roll out and turn another 90 degrees in the opposite direction to line up for a downwind to the runway, i.e. 360 degrees of total turning. How much altitude this will use up will depend on your aircraft, airspeed and the steepness of the bank. I breathe easier after I see some 600 feet "on the clock".
Cowardly Patterns:
If there is a bit of cross wind, some recommend that you can allow it to drift you off to one side as you climb out. Only a 180 degree turn might then line you up for a downwind landing, i.e. half the amount of turning and half the altitude loss of crabbing to obstinately track straight out. Our Richland airport has two perpendicular runways. I take advantage of this fact with what I call my "cowardly pattern". Soon after crossing the end of the runway, I do a 90 degree climbing turn, say to the right. A couple hundred feet higher, I do another. This keeps me close to the airport (it has saved me twice). If all is going well, I continue climbing and wait till near pattern altitude before I depart for where I hope to find lift.
Restarts and Off-Field Landings:
When I first got my PlK, I thought that 500 feet was high enough to do an engine restart. One day I tried a restart while on downwind at a small airport out in the Columbia Basin. The engine didn't start and resisted all efforts to get it going (I may have flooded it). By the time I turned final it was evident that I wouldn't make the runway. I landed hard in a plowed field, and tore off the gear doors. I was lucky that there wasn't more damage. (I immediately retracted the engine - so anyone glancing over from the airport wouldn't realize that it was a motorglider. That would have been too embarrassing!). After that incident, I raised my decision altitude to 1 000 feet AGL. Since then, most of us long-time SLS pilots have increased our engine-restart altitude to 2000 feet AGL. At that altitude, if the engine doesn't start at once (possibly cold soaked or battery low), one can dive to get the prop wind milling, and that may do the trick. If all fails, one has time - before getting down to 1 000 feet to retract the engine and clean the sailplane up for a normal landing including a careful inspection of the selected field, and a pattern that includes downwind, base, and final legs.
Those of us who have been flying self-launching sailplanes for a while operate them exactly as we would a pure sailplane, i.e. make sure that we always have a good landing place within range, don't fly across unlandable terrain without plenty of altitude! Before doing a restart, I like to have the selected field (preferably an airport) directly underneath.
Check Out:
If you are an experienced power pilot with lots of time in complex aircraft, you should have no difficulty checking out in an SLS. If you are a high-time Diamond Badge soaring pilot, and have studied the operating manual carefully (everyone should study and restudy the manual for any aircraft they fly!), you should have no problem. But if you are a low-time glider pilot and transitioning from a training glider, a 1-26, or a simple Standard Class sailplane to an SLS, you should proceed with caution. First, study the flight manual very carefully and listen to experienced SLS pilots. Besides the engine - with its extension and retraction procedures, the aircraft will probably have retractable gear and flaps. Also, lots of switches, levers, cranks, controls and gauges associated with engine operation. One should get some cockpit time on the ground. (An airline captain friend said that when he transitioned from a 1-26 to a big open class sailplane, he put the fuselage into his garage and would sit in it for hours - till he could instantly touch any control or switch, with his eyes closed. Good advice!). I would strongly recommend next taking several high aero tows to check out the stall characteristics, get the "feel" of the sailplane, and to become familiar with the operation of the flaps and dive brakes, all without the distraction of dealing with the engine. Next, do some taxi tests somewhere where there is a big paved ramp. You may find that your SLS doesn't have as positive control on the ground as do most airplanes, and that it can be turned more easily in one direction than the other. On narrow taxi strips, you will have to taxi with the main wheel close to the side of the pavement and the wing tip wheel close to the other. I taxi slowly and with one hand always on the brake, so I can stop quickly if things get out of hand - or a wind gust tips the aircraft over onto the other wing. (One doesn't want to hit a runway light or taxi way marker!). Now, you should be ready to do some takeoffs under power, and to try air restarts (at a safe altitude).
Check Lists:
When I was flying a simple sailplane, I didn't always use a written check list. With the PIK2OE, I always use one. The Flight Manual for the PIK has pages of things one should check. I have boiled this down to a personal
14-item START AND TAKEOFF PROCEDURE,
plus a 4-item ENGINE RETRACT PROCEDURE,
a 7-item ENGINE RESTART,
a 5-item LANDING PROCEDURE
and finally a 5-item SHUT DOWN PROCEDURE.
I have typed all of this onto two sides of a 6"X8" card (protected with transparent shelf paper). I carry it in the map pocket and consult it frequently. Sometimes as a test I will run through the preflight check before looking at the printed list; it is surprising how often I find that I have overlooked something! A local pilot I know with lots of time in a standard class sailplane bought an SLS. Within a month, he had severely damaged it. He got low on a cross country flight, waited too long to try a restart, and landed very hard in a plowed field, apparently without sizing up the field or flying a pattern.
The aircraft was extensively damaged, and he was transported to a hospital complaining of back pains. The ignition switch was found to be in the OFF position. The several lessons are obvious. Another local pilot, this one a highly-experienced former National Soaring Champion, had also bought a self-launcher. Soon thereafter, the engine wouldn't retract. He was able to return safely to the airport and land with the engine extended. The cover on a crucial switch was found not fully closed, preventing its operation. Any of the other retractable-engine sailplanes could experience similar problems - if the pilot fails to follow the procedures specific to their particular sailplane. After my one (and only) gear-up landing, I discovered that the little battery that powers the gear warning system was dead. It is easily checked prior to flight, and doing so is now on my preflight checklist (as is a check of the engine door warning horn)!
Other Considerations:
The newer ships such as the ASH-26E, Nimbus 4DM, Ventus 2cM, LS-9 and DG-808B which extend only the propeller into the air stream, also suffer a degradation of glide angle should the engine fail. And the superb Stemme is in a class of its own. Still, none of these are forgiving training gliders and all need to be flown with care, and engine failure is a serious crisis. There are a few other things with which a new SLS pilot should be familiar. One is how to handle a cross-wind takeoff, or indeed whether to attempt one. Tail dragger SLS'S, such as the PlK, depend on a tail wheel for steering during the start of the takeoff run. Unfortunately, the forward tipping moment of the high-mounted engine removes most or all of the weight from the tail as soon as one opens the throttle fully and starts down the runway. Before reaching flying speed, a gust from the side may cause the aircraft to weather cock right off the runway! Various pilots have devised their own ways to try to handle this problem, such as starting from the down-wind side of a wide runway, advancing the throttle slowly, keeping the appropriate wing down, etc. - or simply not flying if the cross wind exceeds a critical value. It may also be prudent to swallow one's pride and take an aero tow; the pull of the tow line tends to keep the glider going straight. If pure sailplanes are not having a problem launching in a cross wind, you shouldn't either - if you take a tow.
A word also about engine maintenance. Unless you have these skills yourself, this can be a problem. Many A&P's are not familiar with the kind of engines that are used in most of today's SLS's, and really don't want to touch them. Your best bet may be, to try to find a young A&P who came up through Hang Gliding and the Ultra Light movement.
Members of your local EAA chapter may also be a lot of help.
Good luck!
Robert Lee Moore
One Note, please:
Bob tells that he had problems with the PIK 20E during take off - all together seven times!
I personally fly SLS`s since 1990, and I never had such a problem with the DG-400 or DG-808B. Maybe it was luck only!?
Some of the problems he described cannot happen with a DG-808B/C.
But nevertheless: Please fly safely!
- friedel weber -