Short Notes
Index: |
DG takes an interest in "Biological Aviation" |
Searching for Records with a DG-808C Competition
At April 21st Jean Marc Perrin from Bordeaux, France - owner of several world records - took over his new DG-808C Competition, 15m. His intention is, to search for several world records in Argentina next season.
We made some modifications in his glider, to use it in an optimal way for that purpose.
Jean Marc exactly knew the reasons for his decision for a DG-808C Competition:
It's great performance, the best designed motor system and the high reliability of the glider is ideal for his goals.
We like to express our best wishes for his new sailplane and hope that he will have a great success.
...and now in December Jean Marc Perrin with his DG-808C Competition 15m made the "Best Flight of the Year" with 1.600 OLC-Points. Here you can read the details under the date of Dec. 14th 2011:
http://www.onlinecontest.org/olc-2.0/segelflugszene/cmsnews.html?month=122011&news=436#436&mid=552
Congratulation from Bruchsal, although the year 2012 did just start!
Winglets for the LS7 / Increase of Service Time
DG Flugzeugbau restarted the production of winglets for the LS7, which are now accessible to all owners of the LS7. The prefabricated winglets can be ordered at DG Flugzeugbau, whereas the assembly can be executed at each certified repair shop. Hence, the LS7 does not have to be carried to Bruchsal for re-fitting of the winglets.
Attaching the winglets results in better flight characteristics, especially during circling in the thermals and, additionally, enhance the flight path angle.
Here you can find the Technical Note (TM 7008) for the re-fitting of the winglets.
If you process the re-fitting of the winglets, then you should accomplish the Technical Note 7009 (TM 7009), concerning the back hinge of the hood) together with the winglets. This fact is already mentioned in the TM 7008, but the complete description is found in the TM 7009.
Increase of Service Time up to12.000 hours:
The LS7 with Winglets is already certified for a service time of 12.000 hours. So it is not necessary, to make a special certification for the "normal" LS7. If you need to increase your service time up to 9.000 or 12.000 hours, you only have to retrofit winglets and then your can use suitable life extension programs.
Wave Flying in Argentina
Dear Webmaster,
Please find attached a photo I took that you may like to put onto the web page…
The Photo was taken during this year’s IX Wave Soaring Camp at Chos Malal, Argentina. The photo is of Vicky and Marcelo Martino next to their LS 7 with dramatic wave clouds produced by the volcano Tromen just near Chos Malal airfield.
Marcelo is an Argentinean champion mountain wave pilot, who just completed another record flight in his LS7 – “EM”. This day he did a pre-declared task of 1500km. Have a look at the Patagonian gliding web site for more details.
http://www.patagoniagliding.org.ar/Esp%20IX.htm
Chos Malal is the world’s best wave site for speed and distance records. This year alone resulted in over 22 national and world record flights from Chols Malal, including famous pilots such as Klaus and Sidonie Ohlmann, Kathrin Woetzel, Stefano Ghiorzo, Thomas Gostner, Hermann Trimmel, Wolfgang Janowitsch, Ghislaine Facon, Cholo Mirranda, Osvald Ferraro and others.
I also managed to set nine (9) new Australian records from Chos Malal this year (but in a Jantar) :-)))
I hope this of interest
Fly high, fly long, fly fast and fly safely
Kind regards
Dr Richard Agnew
VALUE for money
I read your question about photos of LS - airplanes.
This photo is not unusual, it shows that one can still have good fun, even with older aeroplanes.
Here is a photo of my LS1 over Barcelonnette.
This LS1-d had been flown originally by Mr. Schneider in various competitions and is still in outstanding condition.
I am able to keep up with more modern gliders in the speed range up to 130 km/h, only the payload is not enough for water ballast, unfortunately.
In my view, the different variants of the LS1 are absolute world champions in the class "VALUE for money"
Compliments
Michael Baumann
DG takes an interest in "Biological Aviation"
This photo, from an animal encyclopedia, shows what a healthy Barn Owl looks like.
It was quite cold in the beginning of December in Bruchsal . The thermometer fell during the nights to the upper teens. One day, when our people came to the factory in the dim light of early morning, a Barn Owl was found sitting in front of the glass door at the entrance to the office. How did he get there? Did he fly against the glass door during the night and thus the confused look on his face?
He sat right there while we opened the door and it was obvious that something was not right with him. The owl looked very weak and we wondered what to do with him.
"Unfortunately" our employee was such an animal-lover that she would not take a picture of him because the flash would certainly disturb him and she didn't want to risk that. Another employee called an animal service and they promised to come immediately. There was no problem capturing the owl. They just put a cloth over his head, and the owl was ready to be taken.
We called the next day to see how he was doing. We were told that he was a young owl that had not eaten enough during the cold weather and, exhausted, had sought the warmth of our front door. He had not flown against the door. In the meantime, he had eaten his fill and been take to an "Owl Clinic" in Mannheim where he could spend the rest of the winter.
In the spring, he will be released to the wild where he will share the skies with us even though he flies mostly at times when there are no sailplanes in the skies.
Things happen!
Watch your trim on aero tows
Planes are often towed up at speeds that require a constant push force on the stick. This is usually the only chance to prevent the glider from out climbing the towing plane. Assistance can be granted with the trim. That's the reason for moving the trim to the most forward position possible before the start.
A low time pilot did not think of the trim. He forgot to move it back and was confused that the plane started to dive downwards after the release. He had to use a lot of power to maintain the level of flight and keep the stick in the center position. He landed - frightened - and it took him quite a while to find the cause. Therefore - be aware:
Think of the trim settings! Move it back after the release of the towing cable. Planes equipped with a fast release trim setup make it easier. A click on the trim lever is enough. A DG-200 requires you to move the trim at the side.
Anyway it is a good exercise during a flight to move the trim knob into the most forward and most rearward position to learn the forces, you will need flying the glider with the correct speed.
Anti Collision Light for Gliders?
People occasionally ask us why we don't design an anti collision light for gliders to improve their visibility, as this would be a significant contribution to improving safety and avoiding mid-air collisions.
As early as 1997 we commissioned an engineer to design such a device. Our main concern was of course a minimal power consumption, as this would be the main problem to overcome. Even a solar panel does not generate more than approx. 1 Ampere of current.
The strobe light was mounted on the top of the fuselage and seemed to work fine when we tested it on the ground. Unfortunately the brightness of the flashes was more than inadequate:
When I flew very close to the glider I could see them but as soon as the distance was increased they became invisible and blended into the light appearance of the white glider in the sunlight.
What we need, however, is exactly the opposite:
One should be able to see the flashing strobe light before seeing the glider itself. Our strobe light did not meet this requirement at all. Even an increase of brightness by the factor 10 would probably not be sufficient - one would still not see the light before the glider.
For light aircraft there are strobe lights available with a power consumption of approx. 5 Ampere. For gliders, this is far too high. But even though these strobe lights would improve the visibility of the aircraft at dusk, they would not make any difference in bright sunlight or misty / hazy conditions.
So the result of all this:
Unfortunately it won't work...
Orange-colored Sunglasses
Have you ever tried orange-colored sunglasses instead of your regular sunglasses?
You should try it, the contrast is better, and especially clouds are easier to recognize.
Fuelling Advise
As far as we know a number of our customers wanted to be "good to the motor" and regularly used AVGAS. That is possible in principle, but actually does more damage than good.
AVGAS causes a harsher combustion than MOGAS, because of its high octane rating. One could see this with the Porsche Aircraft engine some time ago. This increases the vibrations of the engine, and that is critical in retractable motor gliders. This is why we want to recommend strongly to all customers: gas up with EURO Super of lead-free 95 and avoid AVGAS whenever possible.
In other countries this type of fuel is widely available, but may go under another name. For instance, in the USA the octane number is expressed as "ROZ" or "MOZ", so that regular fuel has an 82 octane rating. Super probably corresponds to our EURO 95, but please inquire first. (As far as I know, it is okay!)
Again the request, not to fill up out of canisters, but always to use a pump with a filter. It's hard to believe how many unwanted engine stops are cause by dirt getting into the carburetor.
And that once in a while the tank should be drained would not have to be repeated. One customer with a DG-400 was asked after an unscheduled motor stop if he had drained the tank. "Drained? I never drain the tank" he said. So he tore his gear out in an emergency out landing. And that really was not necessary.
A Tip for Starting a Hot Engine
At temperatures above 110 F (45 C) vapor-lock in the carburetor is unavoidable. The consequence of this is that when trying to restart the motor in the air or after landing, the motor catches but fails to run or runs rough. It take some time before it runs at full rpm.
If this happens in the DG-808C with automatic primer or the DG-505MB, press the starter button while the engine is running rough. The starter motor will not run (it's not supposed to) but the primer will inject fuel into the carburetor. Do this two or three times and the motor will begin to run smoothly because fresh fuel is now flowing into the carburetor.
Try it!
Safety Recommendation:
The automatic engine-stowing system must not lead to your forgetting how to use the manual system. To this end, we make the following suggestion:
Every so often at the end of a self launch, open the red cover of the automatic propeller stowage control and turn off the propeller brake. Then retract the engine using the hand brake and the emergency switch just as in the “good old days” of the DG-400. You will soon notice that this requires three hands.
In any case, it's a good exercise!
Can you fully retract the propeller without using the hand brake?
Using the following technique, it is possible:
Let the propeller windmill (or use the starter) to a position just before vertical. It has then passed the motor compartment doors. Use the emergency switch to lower the motor a little past half-way. Wait until the propeller rotates slowly and the LED goes out. That takes a bit longer because at this position, the windmill effect is very weak.
When the LED goes out, lower the propeller all the way down using the emergency switch.
This method is actually quite simple. Once you master this method, the use of the propeller brake that we have installed becomes unnecessary. You also no longer require a " Third hand".
You should practice this technique also from time to time.
Even airline pilots practice emergency procedures
even though they seldom happen.
What do you do if the motor won't retract no matter what the reason?
Extend the motor, start it and fly home or to the nearest airport under power!
Land with or without the engine running.
Windmill Starting the Motor:
Here is another safety recommendation. Every once in a while you should try raising the engine with the emergency switch and windmill starting at a safe, high altitude. Accelerate the glider to 90 knots and set the throttle control at idle. It may require a little courage to push the stick so far forward that the earth appears to be coming up fast. But the faster you accelerate, the sooner you reach the necessary speed to start the engine. After it starts and you pull up, you have lost only about 650 ft.
This also an important thing to practice occasionally!
Landing with the motor running:
In the flight manual of the DG-808B, landing with the motor running is expressly forbidden.
Have you tried it anyway? It's completely unspectacular.
Make the approach with the usual speed (yellow triangle on the ASI plus half the head-wind component) and
with the engine at idle.
The glide angle is a little worse as always because the thrust at idle rpm is a bit higher in comparison to the drag of the engine. Land quite normally while expecting the roll-out to be somewhat longer than usual unless you use a suitable amount of braking.
If it's so simple, why is it forbidden?
The reason is that there is no stall warning indicator.
Every aircraft begins to shake shortly before the laminar flow breaks away from the wing and turbulence bubbles are shed and begin to hit the elevator. This shaking is so noticeable that no stall warning indicator is needed as in airplanes. Modern laminar flow airfoils release very small turbulence bubbles so that the described effect is not so noticeable. If the motor in a motor glider is running, its vibration covers the shaking associated with the approach of stall.
The aircraft has, in effect, no stall warning indication and so landing with a running engine is forbidden by the LBA.
If you want to try it (at your own risk!) for instance at a controlled field, you will be able to follow the flight controller's instructions.
Avoid at all costs a wide, low pattern that could leave you short of the runway in case of engine failure.
Otherwise, a landing with operating engine is harmless!
Improvements for the DG-400
We have been offering improved noise reducing mufflers for the DG-400 series quite some time now. The engine noise is being reduced and felt more pleasantly by everybody thereafter.
It's also very effective additional to exchange the DG-400 propeller with the one of the DG-800A. The engine will gain about 10% more performance and the noise level is instantly changed as well. The tone of the engine will be felt to be more pleasant, too.
In addition the environment will be positively affected due to an increased height once you fly over the first houses after takeoff as a result of the improved power output of the engine.
We greatly recommend that improvement.
Improvement of the Canopy Fit:
New canopies on all new sailplanes are difficult to close because there is still stress in them. This cannot be avoided in production.
Interestingly enough, this characteristic disappears after a few months and the canopies close easily.
The reason for this is that the canopy material and the canopy rim need time to fully post harden and relieve the internal stress.
In order for the two to fit properly after ageing, they must be latched together as much as possible.
For this reason, here is an important suggestion:
When the glider is stored, always latch the canopy - especially with new gliders.
This is especially important if you store your glider in a trailer which stands in full sunlight.
Even if the canopy is difficult to latch, it will be okay latest after one year.
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Sometimes you just can’t close the canopy of a new glider.
That happens when you leave your glider standing in the sun with a closed canopy. The inside air temperature and canopy heat up to a very high temperature. Simply open the canopy for a few minutes in the wind and it will cool off enough to close without any problem.
But the canopy latching system can be modified to remedy this. Whether this is necessary or not can be determined by looking from the left side of fuselage diagonally back to the opening mechanism. Look at the black metal plate with the hole for the locking bolt and through this hole the mating hole on the fuselage. Both holes should more or less line up.
At higher temperatures the canopy expands and the hole on the fuselage side is misaligned with the hole in the locking metal piece. Loosen the 13 mm lock nut on the fuselage side and turn one turn inwards. In winter it can be turned back out again but probably by then the canopy has fitted itself.
Reduction of damage due to electric peaks:
As a student pilot of engine powered aircraft you will likely have learned to switch of all electronics prior to the engine start. That's being done in order to prevent the fragile electronics to be wrecked by electric peaks that are caused by the alternator. Well, radios have been equipped to withstand peaks of up to 600 Volts. Therefore that's not the problem any more, but be aware that on board computers and especially GPS loggers are still endangered by electric peak charges.
We had a DG-400 and a DG-600 in for repairs. Their on board computers were literally blown up by those peak charges. Get in contact with you computer manufacturer and attain information on your model. The only one who knows if his computer is capable of sustaining peak charges is it's manufacturer.
DG-800 pilots and owners are well off by the way. We control the starter motor not by a relay but with heavy duty transistors. That will reduce the mentioned problems and there is no need to worry.
Crumple zone beneath the pilot seat
There is approx. 15 mm of space between the seat and the fuselage in out single seat sailplanes. Only the Bowden cable for the release mechanism of the tow hook and the antenna is down there.
From now on we will fill that space with shock absorbent foam in our DG-800 series aircraft. A crumble zone of 1.5 cm doesn't do much good, but it might be the difference between a sprained and a broken spine. And that's worth more than a piece of foam and 1.5 cm......
"Engine Trouble with my DG-400"
It is correct, that we have not been notified about problems of that specific type before, but that does not hinder us to
suggest a check on the ventilation openings and valves of the gas tank.
The following article was published in the German magazine "Aero Intern" of the DAEC NRW.
There was written:
Our problem occurred during a take off:
The RPM dropped from approx. 6000 to approx. 5400 after around 6 or 7 minutes. The cylinder head temperature rose from 180 to 220 C. The engine was stopped and lowered into the fuselage.
In search for the cause of the mentioned malfunction we noticed that the vent, a small hole approx. 10 cm behind the main gear on the bottom of the fuselage was completely clogged up. Dirt got into the holes and was apparently pressed into the opening even more during the washing sessions. DG-400, 500 and 600 as well as DG-800 type aircraft are equipped with a small aluminum tube connecting the fuel intake to the fuselage bottom.
The engine resumed it's normal operation after the removal of the dirt at the end of the tube. The reduction in rpm was caused by a limited amount of fuel and a leaning out process of the engine resulting in increasing engine temperature. We contacted Mr. Dirks of DG Flugzeugbau and requested to inform all other owners of the possible problem due to the blocked tube.
DG Flugzeugbau denied our request on the basis that such occurrences were not known till then but admitted that the problem might occur on the mentioned aircraft types and advised to properly check the ventilation holes from time to time. The best way to complete that task is to insert a very slim metal wire through the ventilation hole in front of the fuel intake valve.
That wire should end up in the ventilation hole at the bottom of the fuselage when being pushed from the top.
I hope to prevent further problems of the described way.
Dieter Grosskinsky
Luftsportfreunde Dahlemer Binz e.V.
Major Overhaul or Repairs of Rotax Glider Motors
It has happened repeatedly that, after repair or major overhaul, the Rotax factory leaves the motor in a condition such that it requires much more work to reinstall. This is especially the case when Rotax removes the motor electric main plug and when the couplings of the two carburetors of the Rotax 505 are removed.
This is the reason we recommend sending the motors to the Binder Company.
Walter Binder
Motorenbau GmbH
Aulterfrickenhäuser Weg 15
97645 Ostheim v.d. Rhön
Germany
Tel. +4997779200
FAX +4997779201
Walter Binder knows the motor installation in the DG gliders exactly and this guarantees a reinstallation without problems.
Testing Windshields
In an issue of the American "Meat & Poultry" magazine the editor reprinted in "Feathers", the newsletter of the Californian poultry industry the following story:
The American Federal Aviation Administration (FAA) owns a unique in the world machine for testing aircraft windshields. It is a type of catapult which can throw a dead chicken at a speed approximating that of an aircraft in flight.
The theory behind this is the assumption that a windshield that can withstand the chicken's impact can also withstand a collision with a live bird in flight.
British engineers were very interested in this system to test the windshield in a newly designed high-speed locomotive. They borrowed the chicken throwing catapult, loaded it with a chicken, and fired.
The ballistic chicken smashed the windshield, went through the driver's seat, took out an instrument panel and embedded itself in the rear cabin wall.
The British were quite shaken up, and asked the FAA to check the test documentation, to see if they had used the correct methodology. The FAA engineers reviewed the data and sent the following instructions:
"Next time use a thawed chicken"
Experience with L’Hotellier Fittings
Every glider pilot who flies with control hook-ups using L’Hotellier fittings knows the potential danger of these connections.
The use of these damned things has caused the death of many pilots. I think it is absolutely correct that it is now required (in Germany, anyway) that these fittings be safetied every time they are used.
That’s what the little safety pins or so-called Wedekind Safeties are for even though it takes a lot of stupid fumbling to get them on. Even so, we can only repeat, never depend on the L’Hotellier locking ring.
The worst case is when the elevator is connected in this fashion because an undetected failure here is usually fatal.
A story has come to us from the US concerning a DG-400 in which a coupling came apart. In this case, it was an aileron coupling inside the wing. Such couplings are installed at the factory and safetied with safety wire intended to hold together for a long time. The L’Hotellier fitting did not become uncoupled, rather the ball came unscrewed from its place on the pushrod. This failure is just as bad as uncoupling!
The situation did not cause an accident and afterwards the pilot was surprised that the DG-400 flew “nearly normally” with only one working aileron. The roll rate was somewhat slower than usual as one can well imagine. The pilot suspected that the control had been disconnected for some time!
The ball end should be screwed on with "Loctite" and a safety washer installed. That is apparently the better attachment method.
But during a repair, the connection was taken apart and not properly reassembled. Perhaps old Loctite was used. Many mechanics don't know that Loctite can not be stored for more than two years or it becomes unusable. Thus the ball unscrews slowly and at preflight inspection it is noticed that the aileron deflection is wrong or completely uncoupled.
Next time you fly, check the ball joint connections on your L’Hotellier fittings. You only need to look closely at the joint between the ball end and the endplate to see if there is any space between them or if a safety washer is there.
Did you know there are two manufacturers that are still today making and selling gliders with a dozen L’Hotellier fittings in the wings? And those are expensive gliders!
Just thinking of this shakes me up!
Check your radiator water level!
Please check the radiator water level prior to starting the engine.
You do not necessarily need to check it every time if you carefully watch out for blue sediments, but it's better.
You'll notice the blue drops of radiator water in case there is a leakage. It's anti frost liquid and no hydraulic liquid.
It's always important to thoroughly tighten the lid! A customer has not done that and retracted the engine with the lid closed only slightly.
All radiator water leaked out and disappeared through the drainage in the bottom of the engine compartment. Well, the engine quit very fast after a restart.
So PLEASE check on the lid and your radiator water level!