One project has  got stuck in my mind .
Converting my multiplex Twin Star to VTOL. I can take the chance with this plane as it is really stable

Here is an article of the MULTIPLEX magister ( Elapor Version : MENTOR )  40 size aircraft
http://www.rcuniverse.com/magazine/article_display.cfm?article_id=1010

Here are  Photos of the Magister a  single Motor plane converted to twin for VTOL.
There are obvious advantages in such a conversion the Aileron's can be used  to counter the torque roll in Hover mode .

On thinking the only factor that bothers me is the position of the motors when transiting from Hover to flight mode and back  could affect CG   as in the case of Hover the Motors are  along the CG Line  but when transiting to flight mode the motors move forward hence should push the CG forward and make the plane's nose drop and possibly dive , converse is the case when transiting  back the CG  would move back thus pulling the nose up and a possible stall  . Have look at the Twin Photo to get a better understanding of what I mean

Looking for  some inputs if my above concern is valid  

Subu is the VTOL guy on the Forum looking for some  inputs from him as well.

Sai

hey sai uncle welcome to the vtol area.

the tilt wing concept i would say is a bit more easier to stabilize than the tilt rotor. as the ailerons can very very very effectively control yaw and pitch axis believe me i have tested it. for the roll it is mandatory to have a good gyro and i dont think ailerons will be able to handle roll. before that using counter rotating props shall give you less yaw issues and pitch is easy to control with a simple rate gyro i think the pg-03 which you have shall do. in osprey you have to tackle pitch and roll issues as you don't have use of ailerons. anyway for roll i would highly recommend use of gy401 which you i think you have in the store and if thee model is light please use vpp i repeat use vpp as the other method is a very complicated one and takes a lot of tweaking to stabilize and also as gyros were built to control servos not motors though they do it equally well. use you jr9 it will be a lot helpful for you i recommend that venkat should fly it as he has a bit more experience than you sai unlce. i wish i was there i would love to help u in this topic as here we have continuous rains. and finally for the tilt mechanism use two servos for each wing and y cable them. i will post some wiring details too if you need  but before that please use only metal gear servos as the plastic gears shall rip off many times it has happened to me.

aileron servos - vtail - ch1 and ch2 after
elevator servo - use y cable from elevator servo and ch2 of vtail mixer from aileron servo and after the y cable attach a cheap gyro and then back to ch2
for tilt servo just program a flip button and adjust accordingly with the jr9
for the motor - use vtail to ch3 and ch4 from ch4 connector in vtail connect gy series gyro and plug that in into the ch4 (in this case the roll in hover mode will be controlled by the left stick)
rudder will not be used but if you want mix it with aileron.

and you can add a cheap piezo gyro in ch1 to counter any nuisance created by gy gyro in airplane mode

for power connection remove lead of one red wire from esc's bec and feed both esc's with seperate batteries.
vtol with glow is easier as the speed of the engines is controlled by a servo but whats the fun without some prob.

i wish i had one of those twin star i would love to do it if i get a chance to come there i would definetly help out

until then

hail rc india

hope this helps


subbu

Thanks Subu ,  As I expected you were 1st of the Block  .
My concern of shifting CG still is unanswered.
I noticed one more thing in the Magister VTOL there is a 3rd Motor on the tail I guess it is for hover stabilisation , may be it cuts of in case of horizontal flight . If ailerons could control the torque roll then my assumption is the 3rd motor is only for lift and  pitch stability.
For the tilt mechanism , I a thinking of using a GWS retract Servo S136gm http://www.gwsus.com/english/product/servo/low.htm
Connected to the Landing gear Channel
I was also thinking of using the Flap channel to vary the speed of the 3rd Motor .

Any suggestions are welcome .
sai

Gave a little more thought to my concern and I think the  solution is there in the RCU article itself .

One way of addressing my concern is to use the  rear Motor ( 3rd Motor )  for  stability in transit ,my theory  :

The aircraft is made  slightly tail heavy in the hover mode and the rear motor compensates it by providing lift.
At the time of transit either way the rear motor speed is varied to maintain horizontal level of the plane .
Thus when the wings  get into flight mode position the CG shifts forward so is either balanced or slightly nose heavy.

This could be achieved by connecting the rear motor to the flap channel thus enabling variable speed like a throttle

Hey guys I need some inputs to see if I am right.


sai