Hovering with a twin
02-10-2003, 11:33 PM
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Hovering with a twin
Gyros on Twins...The saga continues!!!!
Recently I attended the giant scale fly in at our field with my usual
complement of twin engine planes. (OK, so I had to repair all of them after
the fly in....another story)
The plane used for this experiment is an Ultra Sport 1000 (1002) with two ST 90's and 14x6 props.
Due to a slight power excess, I was able to climb straight up with the best of them. Maybe even do some of the maneuvers that the 3-D ships did. ( OK so they are a "Little" better at smoothness, control, Gee whiz, etc.)
The one feat that they could do well, that I have not mastered, with a twin, is the hover.
There is an inherent problem with conventional twins, in the hover, in that the rudder is not in the direct prop blast of the engines. This drastically reduces the rudder effectiveness. Yes, I have doubled the rudder in size to better control engine out situations, but the hover is a real problem if the
plane yaws to the side. The rudder is not effective enough to recover. As detailed in earlier sections of this series, the engines are already electrically mixed into the rudder to aid the inverted flat spin and hammer head, but the effect is a little bit too late and not effective enough for this maneuver to control.
It is said, in the good book, that jealousy is a sin......Off to the
preacher with me!!
It is also noted that necessity is the mother of invention. ( The definition of jealousy and necessity are so close, in the dictionary, as to be the same as "Obsession") I hate to admit I can't do something.
I have done some small experimenting with gyros in the past and reported to the club the results. This gives me an excess of these electronic wonders.
The plan was to risk my favorite plane, the converted Ultra Sport 1000, to once again go where fools know better. ( Of course my son was all for it as he likes a good crash)
As the engines were already mixed into the rudder on separate channels, there are two separate leads from the separate channels going to the throttle servos. Just what I need for the Hobbico Areo Gyro. (Now I hope that I am not yelled at for naming a brand that on of the moderators does not represent. I just don't have experience with other brands)
I installed the Hobbico Areo Gyro in series with the servo leads, to the engine servos, and positioned the gyro to react to yaw. It takes a lot of gain in the gyro to sense subtle movements on a large plane. It was positioned at approximately the CG.
The idea is to have the engine on the down side of the yaw increase rpm and the upper engine slow down to bring the plane back up to the vertical position. This dampens out the yaw enough to react with the coupled rudder and hold the vertical hover.
I put the gain control on an off on switch, The gain was set at 90%, while on, for maximum sensitivity. The gain setting was arrived (guessed) at by wiggling a 86" plane in my workshop while my son watches the engine reaction, and tries to avoid getting hit by the gyrating mass of plane in a small
confined room. It is necessary to turn the system off for other maneuvers such as flap spin, snap roll, hammer heads, and in case the whole idea "got out of hand."
I also was not so sure about take off and landing. In the above maneuvers, you can imagine the gyro would fight the necessary yaw dramatically.
To make a long story short, the idea WORKED !!!!
The plane is much easier to hover, and control yaw, using the gyro, to assist the hover via differential engine thrust.
Note, the plane is capable of hovering at one half throttle. This is
important, as the gyro needs to be able to add more thrust with additional servo movement on one engine and reduce the throttle on the other. Once again, reliability on a twin cannot be over emphasized.
Torque rolls are not a problem, as the ailerons are more in the prop blast than are normal single engine planes.
It was not a good idea to try a hammer head with the system on, as the plane went nuts !! I won't try that again!!!
Loops were easier and more symmetrical, as were square loops. I, on the second flight, I performed a landing with the gyro on, and it seemed to track smoother. I do not recommend, at least at this point, the take off with the gyro engaged. The individual should test the take off and landing on the individual plane. I now use it all the time with no problems.
Don't do twins.....They make you crazy.!!!!
Recently I attended the giant scale fly in at our field with my usual
complement of twin engine planes. (OK, so I had to repair all of them after
the fly in....another story)
The plane used for this experiment is an Ultra Sport 1000 (1002) with two ST 90's and 14x6 props.
Due to a slight power excess, I was able to climb straight up with the best of them. Maybe even do some of the maneuvers that the 3-D ships did. ( OK so they are a "Little" better at smoothness, control, Gee whiz, etc.)
The one feat that they could do well, that I have not mastered, with a twin, is the hover.
There is an inherent problem with conventional twins, in the hover, in that the rudder is not in the direct prop blast of the engines. This drastically reduces the rudder effectiveness. Yes, I have doubled the rudder in size to better control engine out situations, but the hover is a real problem if the
plane yaws to the side. The rudder is not effective enough to recover. As detailed in earlier sections of this series, the engines are already electrically mixed into the rudder to aid the inverted flat spin and hammer head, but the effect is a little bit too late and not effective enough for this maneuver to control.
It is said, in the good book, that jealousy is a sin......Off to the
preacher with me!!
It is also noted that necessity is the mother of invention. ( The definition of jealousy and necessity are so close, in the dictionary, as to be the same as "Obsession") I hate to admit I can't do something.
I have done some small experimenting with gyros in the past and reported to the club the results. This gives me an excess of these electronic wonders.
The plan was to risk my favorite plane, the converted Ultra Sport 1000, to once again go where fools know better. ( Of course my son was all for it as he likes a good crash)
As the engines were already mixed into the rudder on separate channels, there are two separate leads from the separate channels going to the throttle servos. Just what I need for the Hobbico Areo Gyro. (Now I hope that I am not yelled at for naming a brand that on of the moderators does not represent. I just don't have experience with other brands)
I installed the Hobbico Areo Gyro in series with the servo leads, to the engine servos, and positioned the gyro to react to yaw. It takes a lot of gain in the gyro to sense subtle movements on a large plane. It was positioned at approximately the CG.
The idea is to have the engine on the down side of the yaw increase rpm and the upper engine slow down to bring the plane back up to the vertical position. This dampens out the yaw enough to react with the coupled rudder and hold the vertical hover.
I put the gain control on an off on switch, The gain was set at 90%, while on, for maximum sensitivity. The gain setting was arrived (guessed) at by wiggling a 86" plane in my workshop while my son watches the engine reaction, and tries to avoid getting hit by the gyrating mass of plane in a small
confined room. It is necessary to turn the system off for other maneuvers such as flap spin, snap roll, hammer heads, and in case the whole idea "got out of hand."
I also was not so sure about take off and landing. In the above maneuvers, you can imagine the gyro would fight the necessary yaw dramatically.
To make a long story short, the idea WORKED !!!!
The plane is much easier to hover, and control yaw, using the gyro, to assist the hover via differential engine thrust.
Note, the plane is capable of hovering at one half throttle. This is
important, as the gyro needs to be able to add more thrust with additional servo movement on one engine and reduce the throttle on the other. Once again, reliability on a twin cannot be over emphasized.
Torque rolls are not a problem, as the ailerons are more in the prop blast than are normal single engine planes.
It was not a good idea to try a hammer head with the system on, as the plane went nuts !! I won't try that again!!!
Loops were easier and more symmetrical, as were square loops. I, on the second flight, I performed a landing with the gyro on, and it seemed to track smoother. I do not recommend, at least at this point, the take off with the gyro engaged. The individual should test the take off and landing on the individual plane. I now use it all the time with no problems.
Don't do twins.....They make you crazy.!!!!
02-11-2003, 01:12 AM
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Hovering with a twin
So now it sounds like it is necessary to have an experimental twin that is a quick build with a performance envelop wide enough to do radical experiments like this.
Ultra Sport? Bashed? Another project to add to the ever increasing list.
How about an untra sport with twin tails in addition to twin engines?
Edwin
Ultra Sport? Bashed? Another project to add to the ever increasing list.
How about an untra sport with twin tails in addition to twin engines?
Edwin
02-12-2003, 12:35 PM
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Hovering with a twin
Wouldnt that basically be an ugly stick on a diet? Been kicking around ideas for a twin beater plane. Something that builds quick and would use about .40's to .60's. Would probably set everything up at 0-0-0.
How was the Sequin swapmeet?
Edwin
How was the Sequin swapmeet?
Edwin
02-14-2003, 12:48 AM
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twin hover
Amish Warlord. Yes, I did see that video and decided to let others into how to do that. I liked it.
Edwin,
The Segin meet was pretty good. Blinked and missed a Royal B-17 with retracts and engines for $325...whine whimper!!
Edwin,
The Segin meet was pretty good. Blinked and missed a Royal B-17 with retracts and engines for $325...whine whimper!!
