|The Max II is second version of Max. It also
uses Os Max .46LA with pipe also mounted at 45 deg. and is also mounted directly by screws on
backplate to the firewall.
The model uses my new logaritmic device on flaps. It allows to move CG up to 15% MAC. It gives dead stable straight segments of maneuvers and lot of feedback to handle in round maneuvers, while still able to make standard corners, but definitely without waves.
The model is 1550g heavy. It uses 2 blade UCT BE prop 12x3.5. Aero products Brian Eather pipe at 400mm glow - first baffle. Carb: 7.2mm i.d. with 3.5mm cross spray bar. Lap time 5.2s at 10500 t.o. rpm.
Schema of logharitmic device on flaps
The main idea of the device is in its (almost) LOGARITHMIC function. It means decreasing character. The device is used on flaps unlike direct linkage to elevator.
Here is the elevator (x) to flap (y) ratio as used on this model with the pivot at 55%. Series 1 is 1:1 ratio, series 2 is Logarithmic device.
The picture shows that flaps go more in range up to 22 degrees, while little less in defleflection 30 degrees in corner (compared to the elevator). The feedback from flaps to handle is in same ratio, so it is clear how it works:
1/ Model has nice strong feedback in level and round loops
thanx to more flap deflection around neutral. It stabilizes the model in level
and straight flight. It also makes loops much smoother and pretty round. The
same function makes fly off from corners much better (suppress waves).
2/ 1:1 flap/elevator ratio is not optimal in sharp corners,
so logarithmic device goes till say 27deg in corner instead of 30 in 1:1 ratio.
So the model turns in corner easier itself. It allows to move CG much more to
nose and it gives extra stability. This model has CG at 10% of MAC unlike
similar Max at 19%.
3/ The device carries back much less feedback deflected
than in neutral thanx its function. Thus it needs much less line tension to make
the same corner than same model without it.
4/ The result of point 1/ 2/ and 3/ is model with better ratio between "turnability" in corner and stability in straight flight.
Yes, clear there are also disadvantages especially in
construction or life time, but the model has only few flights now, so we will
Some pictures from building
The foam win and bellcrank installation
Logarithmic device and its components
The device installed in fuselage
The engine mount
And some pictures
Table of dimmensions:
Send mail to email@example.com with questions or comments about
this web site.