David Germany Posted October 22, 2008 Share Posted October 22, 2008 I have aquired a second hand Art-Tech Mini Pred Helicopter which I understand has never flown, but has crashed !. I have replaced the main blades,boom, main gear, boom supports and tail rotor servo. I have run up the motor but have been unable to get the model to lift off into a stable hover, either the heli spins madly on the floor, or it lifts off and starts to bank over to one side, I have no details as to how to set up the rotor head / tail rotors and I'm sure that there must be a logical sequence to follow for this.Any help would be greatly apreciated. Quote Link to comment Share on other sites More sharing options...
Owen Hailey Posted October 22, 2008 Share Posted October 22, 2008 Hi DavidI can try to point you in the right derection, as this is the basic set up needed to get you started and in to a low hover, If you first look at the swash plate in the midel of the heli on the main shaft this is the thing that is conected to the servos, start by disconeting the motor so you can have the radio on and move all the controls in safty, now put the heli at eye level on a flat surfas with all the sticks on the tx at nutral, the swash plate should be level in all derections and square to the shaft in all derections, the throtle stick should then be able to be moved up and down, and all servos should move at the same time to gether, now check the tail servo this should be set so it has equal movement on the servo arm, and the tail blades should be in the nutral and flat possision when the ruder stick is in the midele, this is only the very basic things to look for, and we may need to try other thigs to solve your problems but try this first, and take it very slow and be very slow in your progress, and you will get there in the end.happy setup Owen. Quote Link to comment Share on other sites More sharing options...
David Germany Posted October 22, 2008 Author Share Posted October 22, 2008 Hi OwenHave levelled the swash plate in both directions , when you say all sticks at neutral does that mean the throttle stick in the lowest (off) position, or at mid travel. Also there seems to be a problem with the tail servo which has more travel in one direction than the other (with the pushrod removed), also it does not appear to centre correctly or smoothly. This is a new digital servo that I have replaced. I tried another servo on this chanel and the problem remains, could this be a rx problem?.Hope to try another hover tomorrow.David Quote Link to comment Share on other sites More sharing options...
YakMad Posted October 23, 2008 Share Posted October 23, 2008 David, Change the gyro and make sure you don't have any sub trim on the tail servo, I had similar problems with mine until i realised the gyro was the problem, changed it problem sorted. Also check that none of the servo gear are damaged as I crashed mine and after repairing it, it would not take off, turned out a gear was broken on the collective servo. Quote Link to comment Share on other sites More sharing options...
David Germany Posted October 23, 2008 Author Share Posted October 23, 2008 Thanks YakMadWill check out the servos. I'm sure the problem is at the tail end. The Tx that comes with the Mini Pred does not appear to have sub-trim adjustment as far as I can see, although the symptoms would suggest that this is part of the problem, ie more servo travel in one direction than the other. Maybe I'll try the servo on my DX6i to see what happens.David Quote Link to comment Share on other sites More sharing options...
YakMad Posted October 23, 2008 Share Posted October 23, 2008 David, Forgot to mention the last change I have done is to put the Mini-Pred onto my DX6i and 6100e rx as I suffered lots of glitchs with the rx and tx supplied withy the heli. Quote Link to comment Share on other sites More sharing options...
Owen Hailey Posted October 23, 2008 Share Posted October 23, 2008 Hi DavidYes I did mean the throttle at the lowest point and try the servo strate in the Rx with out the gyro just to check it works ok.good luck Owen. Quote Link to comment Share on other sites More sharing options...
David Germany Posted October 23, 2008 Author Share Posted October 23, 2008 Have checked servo direct from Rx and seems ok. Have noticed that if I throttle up to the point when it just begins to lift and then kill the throttle the heli spins quite violently clockwise until it settles back down ! , is this a normal torque reaction or the symtom of a fault ? Quote Link to comment Share on other sites More sharing options...
Owen Hailey Posted October 23, 2008 Share Posted October 23, 2008 Hi DavidThis is a nomal thing all ways drop the rota speed quite slowly. I get the same thing on both of my 3d helis.Happy hovering Owen. Quote Link to comment Share on other sites More sharing options...
David Germany Posted October 24, 2008 Author Share Posted October 24, 2008 Thanks OwenI'll have to discipline myself with the throttle, my natural reaction as soon as anything looks wrong is to kill the throttle. I'll stop trying to hover in the dining room and try and get outside on Saturday.David Quote Link to comment Share on other sites More sharing options...
David Germany Posted October 29, 2008 Author Share Posted October 29, 2008 Have now managed some short bunny hops but model always drifts. Broke a tail rotor linkage landing on gravel so grounded at the moment. I now feel much more confident that I will get there in the end.Thanks for all the tips.David Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.