Rotax 915 AR1 flight review.

[Vance]

My flight review in an American Ranger powered by a Rotax 915.

Tony is a good friend and a very good flight instructor.

He recently installed a Rotax 915 in his American Ranger.

The Lone Star Rotorcraft Club in Anahuac, TX was having a fly in and Tony offered to put me up in Katy, TX and give me a flight review in his AR1.

I have a primary student that is going to train in his aircraft for private pilot that is not quite ready to fly so I ducked out for a week while he works to make his gyroplane airworthy in my hangar. He was under the supervision of a good air frame and power plant mechanic.

I love any excuse for a road trip.

I had not flown anything powered by a Rotax 915 and I was excited about the opportunity.

I have flown four AR1s and instructed in one. I felt it was a good platform for the Rotax 915. In my opinion it is the nicest two place open tandem gyroplane available today in the USA.

We spent most of the morning doing a careful preflight and greeting friends at the event.

After lunch we spent some time getting me acquainted with the aircraft and planning the flight review.

Various takeoffs and landings, turns around a point, S turns over a road, recognition and recovery from low airspeed and a high rate of descent and various landings including what I refer to as the elevator descent to land.

I have a lot of hours in a lot of different gyroplanes and I find each one flies a little differently.

I prefer steam gages and have to take extra time to understand a flight display like Tony’s AR1 has.

I teach my clients to keep their eyes outside and use the flight instruments to calibrate their sight picture with a quick instrument sweep. To do this I must understand the displays and what I am looking for during the sweep.

Flying at an unfamiliar airport is also a challenge for me as all of my navigation and radio calls are based on the familiar landmarks around the familiar airport.

It would be safe to say most people feel I spend way too much time in pre-flight inspection and flight preparation.

One thing I particularly liked and plan to incorporate in my own flight instruction is in addition the normal three step exchange of controls. Tony also had me repeat back “follow me on the controls” for each maneuver he would demonstrate.

Tony demonstrated the first takeoff on the 60 foot wide 3005 foot long runway 12 and then gave me the flight controls as we climbed out with a departure to the south west.

I was pleased with how smooth the cyclic was and how light the control inputs were.

I immediately climbed two hundred feet too high and briefly struggled with airspeed as I became acquainted with the sight picture. Once I found my references airspeed became easy (plus or minus five miles per hour) and I had less trouble with altitude excursions.

I used Ross Sterling Avenue for my S turns over a road and a pump jack for my turns around a point.

Tony has no inflight adjustable trim on his AR1 and she requires a slight forward pressure to reach the target airspeed of sixty miles per hour.

When it was time to return to the airport I told Tony I was lost. East Texas is somewhat featureless and Anahuac is particularly flat. I had trouble finding the airport till I was nearly on top of it. We were not using a GPS and next time I will wear my prescription goggles as I had some tearing challenges.

After several different takeoffs and landings including a zero airspeed vertical descent I felt comfortable enough to give her full power on the takeoff roll and she leapt into the air without any drama and climbed out with alacrity with no required rudder input.

We lined up on the nineteen hundred foot long grass runway (17) for a stop and go with a considerable gusting cross wind. I went around the first time because I was a little high and not comfortable taking off in the distance that would have remained after a stop and go.

The next pass was a lovely, text book stop and go and it appears I could have managed the takeoff easily in the distance remaining on the first attempt despite the grass being a little wet. The AR1 has generous rudder authority.

There was no perceptible turbo lag; just smooth, steady power directly related to the throttle position.

I was not aware of any power-pitch-yaw coupling from full power to idle at any speed we flew.

Torque roll appeared absent to me and very little rudder was required to deal with the gusting wind on takeoff.

In short the American Ranger with a 915 is a delight to fly with no vices I could detect.

Tony is the 41st instructor I have flown with and in my opinion one of the best.

We have very different styles and Tony never once took the controls despite the divergence.

Only once did he even say anything as I mismanaged his aircraft. I had ballooned up on my flare and Tony felt I should use power to help manage the resulting aggressive descent. I was just more aggressive in the final flare and it worked out fine. I am not certain I would have stayed off the controls in a similar situation. Landing is an edgy time for me as a flight instructor.

Our de-brief went well and Tony went to fly with other clients while I enjoyed interacting with the many people who attended the event.

I am proud to have Tony’s name in my log book.

 

[Resasi]

Nice review Vance.

Informative, good style, concise.

 

[Abid]

Glad you enjoyed flying it Vance. Tony did his own installation and changed from 912 to 915. Not an easy task and did take him months but he re-did all the wiring, all the engine installation, rudder adjustment etc. with some advice from me. Kudos to him. Not all could have done it right.

I'd be so bold to say that the factory installation is very good as well and flies probably even better. We re-inforced the frame for 915 installation with more support for the heavier and 2 inch longer engine and most importantly we changed the tail with a shielded balancing horn on the rudder to lighten up the rudder pressures by 50% (roughly). It makes a big difference on the enclosed canopy version where you do indeed have to put a bit of rudder with power changes similar to open cockpit ELA, MTO or M16. On open AR-1, you can get spoiled and almost forget to use the rudder at all and get away with it. Tony did not install the electro-mechanical pitch trim on his AR-1? I thought he had. It's really handy.

We are seeing 1.8 GPH in smooth 60 deg. F conditions with a 190 pound pilot (one up) plus 3/4 fuel in the tank at 70 mph consistently at close to sea level with 915iS. That is 8.8 hours of endurance with 1 hour reserve left on AR-1 giving 660 miles range on economy cruise.

 

[Vance]

I feel the balance horn on the rudder will be a useful addition.

In a gusting cross wind the rudder pedals were a little heavy in Tony’s ARI just as they are on The Predator.

I have flown four AR1s and instructed in one and it is my favorite open tandem.

I did not find any challenges caused by the extra power that have been described in other gyroplanes with a 915.

If there was torque roll; I could not measure it despite my best efforts.

I did not encounter the yaw on takeoff described on some gyroplanes with the 915. It is just gossip and I have not flown any other 915 powered gyroplanes.

It appeared to me Tony was burning around four gallons an hour while training. I did not monitor it closely.

 

[DavePA11]

What is a balance horn?

 

[Abid]

What is a balance horn?

Short summary is, that its a balance (aerodynamic as well as physical weight) on the other/front side of the hinge line of a control surface that reduces hinge moment (F x d) of a control surface where F is the force acting on a control surface and d is the distance from the point the force F is acted upon to the hinge line.

It reduces the stick or pedal force required by the pilot to move the control surface (reduces hinge moment) when the control surface is large and/or at higher speeds. It also reduces the tendency for fluttering and floating of the control surface making the control surface more effective. A balanced horn combines a surface in front of the hinge line as well as weight in front of the hinge line as desired and computed and tested during engineering development. You do not want to do over-balance. That becomes very dangerous

May sound like a lot but it's fairly simple once you get the idea like everything else. Watch this video if you have 20 minutes and I am sure you'll get it

 

[Abid]

I feel the balance horn on the rudder will be a useful addition.

In a gusting cross wind the rudder pedals were a little heavy in Tony’s ARI just as they are on The Predator.

I have flown four AR1s and instructed in one and it is my favorite open tandem.

I did not find any challenges caused by the extra power that have been described in other gyroplanes with a 915.

If there was torque roll; I could not measure it despite my best efforts.

I did not encounter the yaw on takeoff described on some gyroplanes with the 915. It is just gossip and I have not flown any other 915 powered gyroplanes.

It appeared to me Tony was burning around four gallons an hour while training. I did not monitor it closely.

The torque roll and yaw on AR-1 is much less than most others that look in the same vein.

Tony has the smaller 8.4 meter rotors. We now standardise on 8.6 m and for altitude recommend 8.8 meter. I think those sizes are better. Tony is supposed to do some measurements of his fuel burn and give them to me hopefully sometime soon. You guys probably had 250 pounds more than my careful measurements one up with a 40 pounds extra bag in the back seat (since I am only 150 pounds) to simulate one up typical profile

 

[CGameProgrammer]

I can't believe he upgraded to the 915 but never bothered with the electric trim. I made numerous changes post-build but installing the electric trim was the most crucial and the factory released it three years ago! I think the 915 is wasted without it because then you have to use a lot of forward pressure even at fairly slow cruise speeds without it and it gets exhausting.

It's a surprisingly simple install too.

If I weren't preparing to sell my gyro then I would definitely want a balance horn retrofit too because the rudder pressure is high, but I basically don't use it in cruise flight except for putting pressure on both pedals to counteract the flutter.

 

[anthom]

I can't believe he upgraded to the 915 but never bothered with the electric trim. I made numerous changes post-build but installing the electric trim was the most crucial and the factory released it three years ago! I think the 915 is wasted without it because then you have to use a lot of forward pressure even at fairly slow cruise speeds without it and it gets exhausting.

It's a surprisingly simple install too.

If I weren't preparing to sell my gyro then I would definitely want a balance horn retrofit too because the rudder pressure is high, but I basically don't use it in cruise flight except for putting pressure on both pedals to counteract the flutter.

What is so unbelievable?

Which model gyro are you referring to?

The provision is there to install it in my AR1 with the Averso rotors, and I'm a bit behind as the existing actuator went defective, and I'm in the process to get a new one. Trim is on an as required basis. I do feel the need for some forward trim when I fly alone for speed above 70 mph. But the forces are well balanced with two on board, and one does not feel any adverse effects that necessitate the need for any trim.

Flew the Lama helicopter for a few thousand hours, and it was never equipped with trim or autopilot.

 

[CGameProgrammer]

I mean the AR1 of course. But most of my flights were by myself and I weigh only 160 lbs so I needed a lot of forward pressure.

 

[anthom]

I mean the AR1 of course. But most of my flights were by myself and I weigh only 160 lbs so I needed a lot of forward pressure.

Interestingly, after my change of engine from 912 ULS to 915is, the forward cyclic pressure requirement, which was not much originally, has not changed. I seldom fly alone and when I do, it is manageable for the flight for my weight of 160 lbs as well. In the past, I have done a lot of solo X country and I just got used to applying the forward pressure.

I'm not sure why the installation of the trim was "the most crucial" part of your installation. The trim requirement is more dependent on the rotor system IMHO. I train another pilot in the Magni M24, and without the trim it is very difficult to fly it.

Notwithstanding the present lack of the trim in my AR1, I find it real easy to control and maneuver the gyroplane. I'm glad that Vance had a great flight experience in my gyroplane.

 

[cessna.682]

I only recently got around to replacing my original AR1 trim with the newer system. With the previous design, and the 912ULS, when flying alone I needed a ton of forward pressure to build any significant speed. Interestingly, while flying with the trim system off, pending replacement, I found it flies better than ever. I can easily maintain speeds of 70 to 80 without much pressure. I have enjoyed flying the gyro more than ever. When I install the upgraded system it may be better still, but had I known how good it flew with no trim system, I may have not paid for the upgrade.

 

[CGameProgrammer]

That's interesting, so in your experience the original trim was constantly applying back pressure no matter what. I did not try to fly it with no trim but it definitely should not have been doing that.

For me, the gyro was always very easy to fly; it was only when doing 2+ hour cross-countries where my arm would get very tired from the constant forward pressure.

The new trim is great. The spring allows for plenty of flexibility so you're never fighting the trim (still very easy to maneuver) but you can dial in the trim such that you barely need to touch the cyclic.

The other major post-build upgrades I did were better seats and a constant-speed prop but the trim was definitely the most significant.

 

[DavePA11]

Where did you get the upgraded seats? Thanks!

 

[anthom]

That's interesting, so in your experience the original trim was constantly applying back pressure no matter what. I did not try to fly it with no trim but it definitely should not have been doing that.

For me, the gyro was always very easy to fly; it was only when doing 2+ hour cross-countries where my arm would get very tired from the constant forward pressure.

The new trim is great. The spring allows for plenty of flexibility so you're never fighting the trim (still very easy to maneuver) but you can dial in the trim such that you barely need to touch the cyclic.

The other major post-build upgrades I did were better seats and a constant-speed prop but the trim was definitely the most significant.

The first two production AR1s were the ones that came to Anahuac. Several improvements were incorporated by the manufacturer based on some of our feedback.

Most gyroplanes that I've flown have only got backward trim. The Tango gyro only has backward trim. So is the Dominator and the tandem Air Command that I had before the AR1.

The nose going up with the application of power is normal, and that will also depend on the thrust line offset. The modification was available from Silverlight to incorporate the bi-directional trim a few years ago. Danny was able to do a different kind of modification to offset the forward force application, and that did not need an actuator.

 

[Abid]

AR-1 electro-mechanical speed trim that was released about 3 years ago, trims both ways. Faster and slower than usual neutral around 60 mph. If the trim broke, AR-1 will naturally fly right around 60 mph give or take a few and should have positive but light pressures. So to go faster or to go slower AR-1 needs something to push it or pull it. This is unlike Magni or AutoGyro or ELA where if their trims broke off, you would dive to the ground at very fast speeds which you have to counter by holding stick back with your hands with quite a heavy dose of pressure. Basically they naturally trim at near Vne. AR-1 does not.

AR-1 trim system is a linear actuator but with a spring system that provides cushion and extension capability if the trim jammed (not broke) so the pilot can still override it by hand.

I think Tony and Danny did their own trim systems on the first two AR-1's in the US. Tony's also uses a linear actuator

 

[CGameProgrammer]

Where did you get the upgraded seats? Thanks!

Oregon Aero

 

[Abid]

Oregon Aero

Ed what was done by Oregon Aero for your new seats. I'd be interested in knowing. I am sure we could do similar upgrade options. A handful of people find standard seats on AR-1 not comfortable enough for long flights. I can't say I do but there are so many body types and each has a different tolerance

 

[DavePA11]

I flew to Oshkosh one year in my Cub with crappy seats, and could only manage about 2 hours before back of my legs really hurt from pressure on the metal frame. Ended up finding some foam from Walmart and stuffing it under the seat pad to help on way back from Oshkosh. My Husky has Oregon Aero seats. Would like to know what they did on the gyro too.

CGameProgram - can you post some photos? That would be great!

Dave

 

[CGameProgrammer]

I think the main difference is the foam they used ("Confor" memory foam). I don't ever get sore on long flights anymore, while my butt definitely did with the stock seats. I believe I had them make the bottom cushions thicker than stock too, and raised in front for more of a bucket shape.

The front backrest is thick as well but that was only done so I'd have an easier reach to the cyclic; it's not really a comfort thing.