Chris Dowell Posted October 23, 2019 Share Posted October 23, 2019 I think that my model fly's with about 4-5 deg back tilt. Be VERY careful not to pull back to get your model into the air Tilt head back fully to get head up to speed and as that happens slowly open throttle to get the model moving into the wind...so with head coming up to speed reduce back tilt and increase throttle so the model should be moving faster with head spinning fast . continue to increase throttle and when the model is ready it should lift by itself... and then you can apply back tilt if necessary. If your not happy at any time … pullout Pulling back on the head at low speed will only end in grief....been there done that. Happy landings Chris... Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted October 23, 2019 Share Posted October 23, 2019 https://www.youtube.com/watch?v=r3hVgcSCcY8 Quote Link to comment Share on other sites More sharing options...
Graham L Posted October 23, 2019 Share Posted October 23, 2019 Trevor Aim for a hang angle of around 16/17 degrees. That is a safe c of g at which it flies well. That is what it is on mine and I needed 5 clicks of up trim ( dx8) for it to fly level with the 5 degree backtilt. A heavier nose will need more backtilt on the head and it will not fly as well as it should as the blades will not be as efficient with a higher angle of attack Graham Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted October 23, 2019 Author Share Posted October 23, 2019 Nice one Trevor, It may be worth reducing the thickness of your shims on the blades as well as moving your battery back. More rearward tilt means more drag which requires extra power to push it forwards. Rich Quote Link to comment Share on other sites More sharing options...
Trevor Posted October 23, 2019 Share Posted October 23, 2019 Thanks Rich (and Chris and Graham too). The blades have no shims. This decision was based on experience with my Panther where it was vastly improved by removing the shims. I took care when shaping the blades to keep the leading edge low, which I suspect is the key to shimless operation. A quick play today established that moving the battery back by about four inches is enough to move the hang angle through the recommended range so I’ll put it somewhere in the middle for the next attempt. I’ll keep you posted! Trevor Quote Link to comment Share on other sites More sharing options...
Steve Jones 2 Posted October 24, 2019 Share Posted October 24, 2019 Looks great Trevor, I bet the blades look good in the air !! Both my models run 0.8mm shims. Getting the right amount of nose weigh was important... taking it high, into wind and cutting the throttle the model then drops its nose gently and comes down with a nose down attitude. Initially they did not and would 'sit up' when the power was cut... more nose weight sorted it Steve Quote Link to comment Share on other sites More sharing options...
Trevor Posted October 28, 2019 Share Posted October 28, 2019 Okay, this morning saw the second foray with the Revolver. With the battery re-located rearwards by a couple of inches the hang angle was reduced from 18 to 15 degrees. No other changes were made. The full flight report is in my updated online diary (scroll down to October entry): **LINK** Having just flown the Panther and the Revolver back to back, one clubmate remarked that, although the Revolver seemed to fly very nicely, it lacked the (to him pleasing) 'thwack, thwack' from the rotors. I must confess that the auditory side of things wasn't really commanding much of my limited mental capacity at the time so I can't corroborate this impression but can only imagine that, since the blades are very similar on the two models with the Revolver being a pound and a half lighter, the blades just aren't having to work so hard. I did get the impression that the head seemed to be a little 'lazy' - maybe I should put the RPM sensor on it some time and try to confirm this. If this is an indication that the blades have lift to spare, maybe there would be some merit in trying some thin shims after all, with a view to getting the head speed up a bit and aiding the initial spin up? Anyway, meanwhile, congratulations to the designer chappy on another winner! Trevor Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted October 28, 2019 Author Share Posted October 28, 2019 Congratulations Trevor, an enjoyable blog that is sure to encourage others to have a go at these fascinating flying machines. Rich Quote Link to comment Share on other sites More sharing options...
Trevor Posted November 17, 2019 Share Posted November 17, 2019 Okay, after another couple of flights today, right hand circuits are getting quite a bit better, albeit still not as comfortable as left handers. I have though ended up with quite a bit of left rudder trim and, since the nose still tends to drop a bit in right hand turns, it probably needs a bit more left trim yet. I’d appreciate any advice on adjusting the motor offset to reduce the amount of trim needed - I’m guessing that it needs more offset, but would like to be sure! TIA Trevor Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 17, 2019 Share Posted November 17, 2019 I don't believe that right hand circuits will be quite as good as left handers...although I'm sure ,many would not agree with me . As rule of thumb. I have found with this size model .the off set should be about 6mm to the right. Are you familiar with the hanging thrust test to check the thrust line? Chris... Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 17, 2019 Share Posted November 17, 2019 See if this works... o2czz2XPNM never can post you tube on this site. Chris... Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted November 19, 2019 Author Share Posted November 19, 2019 Chris, This explains how to add a video to a post. Trevor, Sounds like you need to move your motor further out to the right. As Chris suggests (and hopefully he will manage to upload the video ), tethering the model via a string on the rotor spindle and powering the model adjusting the motor until it sits stationary. Your model will fly ok as it is but you will get a slight left yaw as you bleed off the power and vice versa as you increase RPM. Right hand roll turns will almost certainly be effected as your set up stands but they will always require a little more control input than left handers due to the CCW blade rotation. Rich Quote Link to comment Share on other sites More sharing options...
Trevor Posted November 19, 2019 Share Posted November 19, 2019 Thanks for the responses. I had read about the suspension method of adjusting the thrust line but frankly didn't fancy the prospect and had enough confidence in Rich's recommended starting point to do the initial flight tests and hopefully fine tune the setup from there. Rich, thanks for confirming that I need more motor offset rather than less. The motor is fitted with Malcolm's adjustable motor mount so I can easily move it a bit, although the motor mount is already close to the edge of the bulkhead. I didn't notice any significant change in yaw trim with power so I don't think it can be too far out. With regard to the rudder trim, the irony is that when I first fitted the tail surfaces to the boom they were off square and I spent a fair bit of time fiddling around to square everything up. Had I not bothered, there would have been a bit of offset built into the fins from the outset! Anyway, I'll keep practising the right hand circuits. Cheers, Trevor Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted November 19, 2019 Author Share Posted November 19, 2019 Trevor, Everyone goes their own way which adds many variables, motor KV, prop diameter/pitch etc, these all effect the offset which is why it is necessary to 'fine tune' each particular model. Rich Quote Link to comment Share on other sites More sharing options...
Steve Jones 2 Posted November 19, 2019 Share Posted November 19, 2019 Both my revolvers have a left rudder offset. Quiet large and on the first Malc at coolwind provided a motor plate with a larger right offset . Almost 12mm it made little difference to the rudder offset so I ignore and just go fly does this offset affect flying trim with power , yes but who cares .. I just get on with it and fly it my go too models and great fun .. modelling is not an exact science and I would rather fly and have fun steve Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 20, 2019 Share Posted November 20, 2019 Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 20, 2019 Share Posted November 20, 2019 Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 20, 2019 Share Posted November 20, 2019 Thanks again Rich...just hope I can remember...thought I might show these also. Chris... Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 20, 2019 Share Posted November 20, 2019 Quote Link to comment Share on other sites More sharing options...
Graham L Posted November 20, 2019 Share Posted November 20, 2019 Hi Trevor You will need your motor as far to the right as you can and even with this you will still need rudder offset to compensate for the spiral slipstream on the fin and rudder. This is a fact of life with most short boom pushers both model and full size. On my Revolver the offset is only needed above 15-20% throttle and so I have programmed a throttle rudder mix in the tx to remove the offset below this. Using a Spektrum DX8 the activated mix screen reads- throttle rudder, rate 0, rate 9,offset -15, trim act and programmed on gear switch 1 giving the option to switch the mix off. Everyone’s set up is a bit different and would need fine tuning for each model but it certainly significantly reduces the tail yaw when throttling right back. As Steve says you could just manually compensate on the sticks but feel that having paid out for modern radio I might as well use its benefits. If you don’t get on with it then at least you can switch the mix off. Graham Quote Link to comment Share on other sites More sharing options...
Trevor Posted November 20, 2019 Share Posted November 20, 2019 Thanks Graham. I’ll offset the motor as much as possible without it looking silly and then take it from there. I do have the facility to program a throttle to rudder mix as you describe (Jeti radio) so will bear that in mind. Trevor Quote Link to comment Share on other sites More sharing options...
Richard Harris Posted November 21, 2019 Author Share Posted November 21, 2019 Chris, A rare event from Mr Hand launch! ,Glad you figured the video embedding out and thanks for posting them Rich Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 21, 2019 Share Posted November 21, 2019 Mr hand launch....I like that . Well I'm glad you can still see the video ..cos all I get is a black box must be a location thing...……. Chris... Quote Link to comment Share on other sites More sharing options...
Chris Dowell Posted November 21, 2019 Share Posted November 21, 2019 Don't panic...all fixed I can see.. Chris... Quote Link to comment Share on other sites More sharing options...
Trevor Posted November 24, 2019 Share Posted November 24, 2019 With a bit more motor offset, the rudder trim is reduced but not quite eliminated. I didn’t notice any throttle/yaw coupling and circuits both ways are now okay. Just as well really since today’s wind direction necessitated taking off straight into a right hand circuit. In spite of the gloomy conditions, clubmate Mike managed a few photos: They’re a bit blurry but do show off the coning angle rather well. Trevor Edited By Trevor on 24/11/2019 17:12:11 Quote Link to comment Share on other sites More sharing options...
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