What are the differences between the mounting adapters SUN, UN and UNG?
The mounting adapter SUN is approximately 20mm longer than adapter UN. That allows the use of inserts that open the opportunity to plug in either single probes of type ST1 30mm or dual probes of type ST2 without modification of the tubing. This gives you maximum flexibility in the selection of probes.
While using UN adapter in combination with a carbon shaft probe there will be a visible gap between the adapter and the probe, we offer a suitable spacer sleeve to fill the gap. The mounting adapter UNG is designed to hold bend probes, first choice for aircraft with front-mounted engines like FES or TMG.
Is it possible to keep the probe permanently mounted to the aircraft?
Especially the probes with an aluminum end piece are advised to be removed before dismantling and to store it safely. When transporting over uneven terrain, especially on grass fields or when transporting in trailers, the aluminum end piece can be damaged by vibrations and strong impacts. This can lead to the fact that it breaks in the future under the lowest stress. After removing the probe, always seal the mounting hole in the tail unit (tape, cap, etc.)!
Which esa systems probe or nozzle is recommended for my airplane?
Generally, the probe/nozzle has to be considered independent of the airplane type. A well-compensated probe or nozzle should deliver a pressure coefficient close to -1 (cp probe = (p stat – p total) / p dyn). This coefficient should be as independent of the airspeed as possible, and the probe/nozzle must be able to work in a wide range of yaw and pitch angles. Our probes meet these criteria to an exacting degree.
Another point to consider when searching for a suitable probe is the personal preferences of the pilot: But when there is a problem with the compensation, the first thing to check is the pressure integrity of the entire system. Instructions for checking the pressure tightness of the entire pressure system.
One exception may be cloud flying: in adverse conditions, clouds can temporarily block the TE conduits of most multi-probes due to the excessive amount of moisture. For flying in clouds, the right choice among the multi-probes is the type DN/Statek and StaTEK/Brözel probes because like in the single probes, the TE is fed through a wider shaft.
What should be consider when installing a new mounting adapter?
The installation should be carried out by experienced specialists.
The vertical stabilizer is the most suitable installation location as it offers a good compromise in terms of airflow and ground handling.
For optimal operation we recommend installing the adapter hose connectors upwards (function as a siphon), the horizontal orientation parallel to the longitudinal zero axis and the use of hard-walled pipes in the fuselage till under the seat pan. The TE pressure connection should be split here and the connection from this point to the instruments should be done using 8/4mm silicone tubes.
How to connect the instruments?
Unless otherwise advised by the airplane manufacturer, only the varios and the flight computer should be connected to a (multi-) probe.
In cases where both a mechanical and an electronic vario are to be connected, the split in the TE tube should be done as far from the instrument panel as possible. For example, under the seat pan. ASI and altimeter must be connected as described in the manufacturer’s manual!
Which type of tube should be used for the pressure system?
For the connection of the instruments, we recommend a high-quality, talcum-free silicone tube measuring 8/4mm (2mm wall thickness). This tube does not kink and remains flexible for years which is important for a secure, tight fit. The connection from underneath the seat pan to the fin should be done with 6/4mm or 6/2mm PE-LD pipe.
How should my esa-systems probe or nozzle be aligned?
Both in practice as well as in literature, one sees again and again probes and nozzles installed with the TE head in a downwards position, but the correct way is with the TE head pointing upwards!
The only two exceptions are esa-systems probes of type DN/: these probes have two TE measurement points pointing sideways and must be aligned parallel to the wings in order to return precise measurements. And in case the vertical stabilizer has two mounting adapters installed, the probes need to be oriented so that they may not influence each other.
Procedure for quickly checking the pressure tightness of a single TE probe
Warning: Testing should never be done using compressed air, this can quickly destroy the tubing. The TE probes /UN cannot reliable be checked through quick tests.
Depending on the model, 1-2 TE ports must be tightly sealed. A tightly fitting silicone tubing or “fingers” where tubing does not fit are more suitable for this purpose than duct tape!
After sealing, you must create a partial vacuum: this is done by sucking through your mouth on the open end of the tube and then covering the opening with your tongue to seal it off. If the O-rings are in optimal condition and the suction against your tongue remains for at least 20 seconds, then the probe itself can be considered sufficiently airtight. Should the probe prove to be leaky we can offer to repair it.
For a more thorough inspection please follow the section. 'Instructions for checking the pressure tightness of the entire system'.
Instructions for checking the pressure tightness of the entire pressure system
The tightness of the pressure system is fundamental to the proper operation of all instruments. This should be checked in regular intervals. For the tests you will need the following:
- the air speed indicator
- a medical syringe, approx. 60ml; for a tight fit, lubricate the plunger with some Vaseline
- a piece of silicone tube, approx. 40cm
- a suitable T-connector - See more here.
How should an electronical Vario be set if connected to a TE probe?
Recent electronic varios usually offer an option for either electronic or pressure probe compensation. For a good compensation it is usually necessary to select the probe compensation and set any correction filters to 0%.
How can I verify the quality of the compensation?
A prerequisite for checking is that the flights are carried out in calm air (first sunlight and wind still). Test flights require some practice, and the instruments should be recorded, if possible, by video camera. This helps to exclude emotional interpretations. In the normal case, esa systems probes and nozzles are well compensated and do not require any adjustment. The graphic helps to correctly interpret the vario readings. If the readings are not within the expected limits, please check the following recommendations to isolate and eliminate the cause 'The vario compensation is not satisfying; what can I do?'
The fit of the probe in the mounting adapter is very loose, what can I do?
Especially in the case of gliders with a year of manufacture before 1998, it may happen that an external adapter has been fitted which does not have the required interior dimensions. In such cases, the use of adhesive tape or, in extreme cases, the use of minimally thicker (+0,1mm) O-rings can help.
What is the purpose of the STOP sticker on the all-metal probes?
Straight, non-bent whole-metal probes usually have no stop sleeve. Therefore, the STOP sticker indicates how far the probe has to be inserted in order to function properly.
ATTENTION: The old mounting adapter type UN is 20mm shorter than the latest mounting adapter SUN. If a probe with a STOP sticker originally made for the length of an adapter UN is plugged into a 20mm longer SUN adapter, the STOP sticker is in the wrong position! The probe must then be inserted 20mm deeper than the STOP sticker indicates, otherwise the probe will fail. In such cases the sticker should be replaced, esa systems will provide you with a spare sticker. The function of all instruments connected to a probe must be checked before each take off!
What maintenance of the probe is sensible or required?
In principle, the whole pressure system is maintenance-free, if the end pieces of the probes are always greased before insertion, and the measuring heads are wiped from time to time with a clean cloth. Never use compressed air or pointed objects for cleaning / testing! If the heads have been cleaned under running water, please ensure that all water is removed from the tubing before takeoff - NOT BY USE OF COMPRESSED AIR! The O-rings of the probes with the end pieces ST1 and ST2 should be regularly inspected for wear / tears (magnifying glass!) and replaced if necessary.
The vario compensation is not satisfactory; what can I do?
Several sources of errors can cause an unsatisfactory compensation and must be examined to isolate and eliminate them. The possible errors in the order of the frequency known to us.
- Leakage in the system from probe to instrument
- Swapped connections of TEK and p-stat
- Probe is not inserted far enough
- Foreign bodies or insects in the adapter
- Flight computer misconnected
- Division of the TE instrument hose directly in front of the instruments (turbulence!)
- Incorrect configuration of the computer
- Leaking instruments
A concrete guide for step-by-step troubleshooting of the system can is listed under 'Instructions for checking the pressure tightness of the entire pressure system'.
When do the O-rings in the mounting adapter type SUN, UN and UNG need a replacement?
Non-greased end pieces can destroy the O-rings in the mounting adapters relatively quickly, in which case an exchange is necessary. In general, only the first two rings in the adapter are affected in such cases. Should an exchange be necessary, (leak test), we provide a replacement tool and replacement rings with which the O-rings can be exchanged. 'The O-rings in the mounting adapter are defective. Where can I find replacements and how do I change them?'
Can an esa systems mounting adapter be easily shortened?
This is only possible in a few exceptional cases. If this is necessary, please contact us beforehand, to minimize incompatibilities!
The O-rings in the mounting adapter are defective. How do I change them?
If the shaft of the probe / nozzle is kept clean and is smoothly treated with Vaseline or silicone grease, the rings hold almost unlimited (current long-term experience > 15 years). If the O-rings are not maintained the O-rings and here in particular the O-ring 1 can be easily destroyed by abrasion, which leads to leakage in the system and thus to useless readings. The exchange of the O-ring (s) is then mandatory.
The mounting adapters UN, SUN and UNG each have three internal O-rings for sealing the pressures applied via a multi probe. For the O-rings 1 and 2 we show here the possibility of the exchange while the mounting adapter is built in. The exchange of the 3rd O-ring in the built-in state is also possible but is not officially supported by us since a higher degree of craftsmanship is required for this exchange. Good to know: Compared to the first O-ring, the third O-ring is roughly 10x less affected by friction and is therefore very rarely defective. See more here.
The O-rings on an end piece are defective where do I get replacement?
On request ESA will send replacement. Please attach a photo of the end piece.
End piece ST1 requires 2 pie 5.5x1.5 or 5.0x1.5 FKM or NBR70
End piece ST2 requires 2 pie 5.5x1.5 or 5.0x1.5 + 1 pie 3.0x1.5 FKM or NBR70
End piece ST1-6mm requires 1 pie 3.1x1.6 or 3.0x1.5 FKM or NBR70
Adaptor cap AV 8 mm 1 pie 5.5x1.5 or 5.0x1.5 FKM or NBR70
Adaptor cap AV 6 mm 1 pie 3.1x1.6 or 3.0x1.5 FKM or NBR70
O-Ring Replacement Instructions
