F3B or F3J launch tension logging may be a demanding application for the Max1025 tension transducer.
Even if the transducer itself is rugged and well capable of withstanding the forces experienced
during launch, some extra precautions can be taken to ensure that linkages and connections
are protected and stay safe even when something goes wrong.
Francesco Meschia,helper of the Italian F3J team, has prepared an almost definitive article on F3J launch. Starting with theory, he developes a systematic method based on inflight measurements to optimise the parameters of the wire, hook position etc....
The result is great in terms of glider altitude improvement.
To complete this achievement, he systematically uses video and data logged on board during lauch phase. He highlights the importance of the pulling force measurement and uses for that purpose our Max1025 traction transducer as described in the Xerivision AN-002 - Zoom anatomy investigation.
Download here the complete Francesco's article in Italian "Dalla spanna al datalogger".
The concepts of design and use behind the Max 1401 transducer
It is well known that the aerodynamic efficiency of a model is degraded by its yaw behaviour during the turning manoeuvres. This degradation grows with the high wings aspect ratio values of performance and competition gliders. The pilot tries to counter balance this effect with 3 axis piloting, having only, as a feed back of his efforts, the global result of the model eventually climbing or not in the thermal. The Mle 1401 yaw transducer continuously measures the angle of attack of the fuselage of the model and, connected to a Xerivision Xerus system, transmits to the ground on a HUD and/or on board records the current measured values for future data processing. The benefit is twofold: first, with the Lynx HUD the pilot has in real time the yaw angle of his model in sight during the spiral and can improve his judgment and his piloting skill keeping in sight his model using this short feed-back loop. Second, the off line study of the records give precious and appropriate information on the dynamic behaviour of the model and leads to a design improvement and/or an assessment of the various theories in this domain which are numerous because the measurements are scarce. Read more....
Francesco Meschia from Asti has used successfully our Mle 1025 traction transducer for investigation of the wire tension during the zoom phase of an F3J Pike Perfekt flight. About 20 measurement flights have been achieved to date allowing Francesco
to begin to build up a good test data base for F3J. With few support and a specific adjustment of the transducer's offset from
our side and thank to his skills in electronics, he was able to interface our transducer to his Unilog data logger.Here are 2 sample plots. He plans to publish soon an exciting article in RCSD. Here is Francesco's website: http://ilgabbianorc.blogspot.com
Xerus 1.26 software release: This release introduces a new functionnality of 5Hz GPS data on board calculation and transmission to the ground on the HUD. The pilot can continuously monitor the distance of his airplane. He can switch at any time the display to altitude or speed. This allow a complete control of the flight and the flight manouvers are no more approximative: you exactly lower the flaps of your jet for landing at the right place. If the embedded system is a Xerus expert, which has a recording capacity, he can record the flight path and plot it in Flight Test Studio 1.2 (FTS) the flight data analysis software.
FTS is integrated with Google Earth and produces files that you can open directly in GE.
AN-0001 - The Lynx HUD concept
AN-0002 - F3B zoom anatomy investigation
AN-0003 Yaw behaviour investigation with Max 1400 transducers
Flight test reportsF3B High G measurement 27.2 G achieved during the zoom
Airspeed during F3B zoom : 71 m/s(255 km/h) peak airspeed achieved during the zoom
Aerodynamic, measurement, technical links
Access to the complete set of Matthieu Scherrer publications on his website
And Matthieu Scherrer's blog here
See the XFLR5 web site from André Deperrois.
Download this outstanding virtual windtunnel et learn how to play with it.
Interresting commecial linksSee also the
Marc Pujol new electric glider F3J Genoma
Here is the complete dossier : design & make of this wonderful cloud suppository.
A 1st document with the design process and philosophy of the model with all the details of the concept, the calculations with XFLR5.
A zip file with a complete set of CNC files under Galaad for easy and automated manufacturing of the Genoma' ribs
A 32Mbyte zip file presenting the tips of construction, the measurement of performances with Xerivion hardware and software.
Pujol's Article - Stabilité latérale
Is V - tail better that than X - tail ?
HUD : a
new concept in RC modelling
Improve your pilot skills. Interact in real time more precisely
See our video
XFLR5 results analysis
Results_vs_Prediction by André Deperrois
Which CL are you really flying?