extralite Posted July 8, 2021 Posted July 8, 2021 (edited) Had a first fly of a t300 with a 582 engine and bolly prop after putting the wings back on that had been removed for transport. It seems to pitch down as power increased that made the first take-offs interesting. Once power is reduced to idle it flies beautifully. Possible reasons i can think of are the thrust line pointed down but i can't think of why that would be. Also the thrust line being above the centre of gravity, but it looks like a normal Thruster. Lastly something to do with the tailplane. For example, if the angle of the attack of the tailplane is high, the extra slipstream over the tail causing a pitch down movement. Anyone else got any ideas? We should soon have 3 Thusters in the one shed (Thanks Old Koreelah) and its good fun climbing into them. Cold, noisy, breezy..old school feeling. Edited July 8, 2021 by extralite 1
Thruster88 Posted July 9, 2021 Posted July 9, 2021 Hello Craig, Graeme called me about this yesterday. I have never experienced this except in one thruster in the rudder, it would pull on the rudder pedals due to the skins not being tight. My thruster has the stick at 90° to floor with neutral elevator, it flies in this position. 582, B box and two blade bolly. You could also check C of G. You have an excellent selection of aircraft.
facthunter Posted July 9, 2021 Posted July 9, 2021 The thrust line is above the centre of drag and mass so some should/could be expected . Is the grass long at your drome.? You could check the thrust line Cof G and general rigging.. talk to the previous owner/operator. I've forgotten my first impressions. except that closing the throttle meant you were going down and you only had 300' to start with. Nev
extralite Posted July 9, 2021 Author Posted July 9, 2021 Hi Kirk..you will have to come out once we have them together. For Facthunter...it happens even when airborne. It is the 3rd thruster i have flown and while they all are heavy at the front, this one seems to be more so when powered up. Maybe it is a t300 thing with the bigger engine. Combined with it yawing a lot to the left at the moment at any time ( a rudder trim tab that has been fitted might be the wrong way) it made those first hops before we knew these things about it interesting. Another thing, the cables under the front main wing are quite slack on the ground compared to the t500.
FlyBoy1960 Posted July 9, 2021 Posted July 9, 2021 The Mudgee aeroclub brought a thruster that did exactly this, it would porpoise at different power settings, really aggressively. I know one of the guys down there and will see if they can remember the cure. It must be at least 30 years ago now that they got this aircraft and they crashed it on Boxing Day rolling it up into a ball but it did fly again. I have a vague memory it was something to do with the fabric on the tail feathers but I will have to ask them because I just don't remember.
facthunter Posted July 9, 2021 Posted July 9, 2021 The first one I flew was NEW. It flew pretty normally. I blame loose fabric for a lot of the control differences . The elevator is more responsive with power on .(Not an unusual thing with a lot of planes). Nev
Thruster88 Posted July 9, 2021 Posted July 9, 2021 2 hours ago, FlyBoy1960 said: The Mudgee aeroclub brought a thruster that did exactly this, it would porpoise at different power settings, really aggressively. I know one of the guys down there and will see if they can remember the cure. It must be at least 30 years ago now that they got this aircraft and they crashed it on Boxing Day rolling it up into a ball but it did fly again. I have a vague memory it was something to do with the fabric on the tail feathers but I will have to ask them because I just don't remember. That one was caused by loose skins on the horizontal stabilizer and or elevator. There was also talk of the exhaust muffler angle creating turbulence. The Y piece out of the engine should point down so the muffler is better oriented to the up flow over the wing.
tillmanr Posted July 9, 2021 Posted July 9, 2021 I recall a flyer who added a strip of aluminium angle about 12mm to the outside bottom edge of the doors to stiffen them. Amazingly it virtually cancelled any elevator control . The aeros on this supposedly simple aircraft should not be played with impulsively.
extralite Posted July 9, 2021 Author Posted July 9, 2021 Great, thanks for input. Skin are tight. Pretty new. Everything looks very good on it really. It flies okay other than the yaw, the pitch down was just a surprise. Will investigate further.
T300 Posted July 19, 2022 Posted July 19, 2022 Sorry I’m, a bit late to the party on this thread as I only found this forum today by accident when looking for something else. Did you ever get to the bottom of this issue at all? one possible cause for this can be the centre wing panel on the upper surface of the wing if the Velcro fasteners on its edges aren’t sealing so well any longer. The propwash at full power will suck some air out of the wings flattening the wing profile slightly and giving and aggressive pitch down with with power which is restored again when you close the throttle. All the other explanations given previously are definite possibilities, but I have seen this particular issue on a Thruster before caused by the centre panel not sealing well. regards, Simon 1 1
Thruster88 Posted July 20, 2022 Posted July 20, 2022 It was loose elevator skin, very strange to fly. https://www.facebook.com/groups/1611498805859763/permalink/1738826479793661/ 2
extralite Posted July 20, 2022 Author Posted July 20, 2022 (edited) The loose elevator skin solved most of it. Still pitches down a bit with power though (most noticeable when low flying). Love the thruster but balanced controls are not their strong suite. They all fly a bit different. Anyone know where I might be able to get the plastic inserts that fit into the back of the wing battons? Edited July 20, 2022 by extralite
facthunter Posted July 21, 2022 Posted July 21, 2022 Having the thrust line way above the centre of gravity AND centre of drag it's inevitable the effect will be as it is. After a while you'll anticipate it and hardly notice it. Nev
Siso Posted July 21, 2022 Posted July 21, 2022 The plastic plugs for the wing battens are available from Clark Rubber
Siso Posted July 21, 2022 Posted July 21, 2022 https://www.clarkrubber.com.au/products/6879p-round-plastic-internal-chair-tip-black
extralite Posted July 21, 2022 Author Posted July 21, 2022 Wow isnt this an amazing resource....I am not near the aircraft Siso, do you happen to know the size?
IBob Posted July 22, 2022 Posted July 22, 2022 On 21/07/2022 at 4:41 PM, extralite said: Wow isnt this an amazing resource....I am not near the aircraft Siso, do you happen to know the size? It is a wonderful resource, extralite..........would be even better if more folk actively shared their experiences here. We all get to benefit and learn.......) 2 2
BrendAn Posted July 25, 2022 Posted July 25, 2022 On 21/07/2022 at 2:41 PM, extralite said: Wow isnt this an amazing resource....I am not near the aircraft Siso, do you happen to know the size? What's going on with thruster rego. Have U transferred it. I also sent you the manuals and you haven't even let me if you got them
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