Da Butterfly

A student of mine bought one of Larry Neal's 503 DC Butterfly gyros. I got to play with it a little yesterday.

Fit and finish are very nice. The all-steel pump-handle joystick is very similar to the original Bensen unit (which is a good one).

The Air Command ancestry is obvious in the airframe. The front end of the frame is pure Air Comm. The remainder of the craft uses the bolted U-bracket system seen in Air Command, Sport Copter, Soma and to some extent the Gyrobee. This system cuts labor cost and time, but drives structural engineers nuts.

Larry's Metro-launch prerotator is a sophisticated version of the "long belt" device sometimes seen on VW and Soob engines; a pulley on the front end of the crank drives a long belt that runs up the mast, takes a 90-deg turn aft and powers the rotor through a centrifugal clutch. This thing is extremely powerful. There are quite a number of moving parts, including a 12v air compressor that engages the device, six idler wheels, the clutch and (I think) a Bendix. One must keep a very close eye on all this hardware up on the mast; such stuff is always tempted to take a trip into the prop.

The integrity of the pressed-together Rotax crank is an issue when taking power straight off the crank (i.e. not through the gearbox, with its slip function). I imagine that's why this unit does not give the pilot the job of directly engaging or slipping the clutch. These functions are performed by robots: the air compressor and centrifugal clutch.

Most interesting to me was the flying. The machine flies much like a Dominator, but with less pitching of the nose upon throttle changes. The large HS in the center of the propwash makes for very solid pitch stability, even on a somewhat gusty day.

The vertical tail is "half height," not "tall tail," so there's some tendency to roll with engine torque upon takeoff. With practice, you'll know just where to point the stick to minimize this effect.

I landed conventionally and didn't try out the long-stroke gear. We've all the seen the videos.

Ground handling is childishly simple. There's direct nosewheel steering using the rudder pedals, with slack in the cables that lead to the wheel to allow for slip landings. We didn't have a crosswind that would have allowed me to try this out. Direct-linked steering systems tend to be bugged by a tendency to swerve upon setting the nose down when holding rudder against a crosswind. Slack cables, springs and cams have all been used in the past to minimize the problem.

It's always fun to fly a single-place gyro after driving the tandem limo. You do get spoiled by the higher cruise speed of the big machine.

Good report!
Thanks Doug.
Heron

Hello Mr Riley.

Thank You for the first hand info on the butterfly and its the Metro launch system. Now I know how its driven.

Would this set up be great for a prerotator set up, as you said, its powerful.

Best wishes.
Rehan

New Metro Launch Pre-Rotator

New Metro Launch Pre-Rotator

FYI - Because the assembly of pulleys at the top of the mast gets in the way of the fully enclosed cab Larry is developing for the Butterfly, he is in the process of re-designing the Metro Launch System. His new system will use a shaft to drive the same high power Pre-Rotator and give the same 325 RRPM but without all the moving parts and complexity of the current system. It will still use the robotic air compressor to initiate the process and to disengage the system. It sounds pretty exciting to me. I will let you all know more as I hear more about it.

Gyro Doug

The M-L system certainly is powerful. I didn't run it all the way up; just to 200 RRPM or so. Test-flying was tops on the agenda and we had a 4000 foot runway anyway. Also, the hydraulic brakes were getting soft and holding the the machine back was becoming difficult.

Dan LeCuyer, the owner, has run it up to 5000+ engine RPM, which apparently translated to RRPM in high 200's. He sent me a video and, while the camera tends to freeze the rotor, the soundtrack of rotor noise tells you how fast it's going.

This rig clearly capitalizes on some excess horsepower somewhere in the 503 DC's power curve -- excess relative to what's needed to spin the prop. The prop on Dan's machine is a 3-blade Powerfin that did not seem abnormally low-pitched; revs were where they should be for a "climb" prop.

Doug, it will be good to see a reduction in the amount of plunder sitting up there on the mast.

The remaining issue in my mind about this system is the protection of the crankshaft from misalignment caused by the novel power-takeoff mode. Obviously some work has gone into making this rig a "soft start" -- something that will be gentle on the crank. Whether it will shorten the 300 hr. TBO on the Rotax crank is a valid question.

I see Larry Neal just put up some new pictures of the sky cycle on his web page with the wheel fairings on it. It gives new meaning to the word fin!

Doug a very clear and informative report. With your knowledge of the Butterfly have you been able to examine the various changes made on the Carter copter test vehicle or feel able to comment on the prerotator used on that( or is it the same), rotor and drive prop?

I have become interested in autogyros through seeing this one and the big prototype, and am very keen to see what experts in the field have to say about his developments.

Update & Clarification on Metro Launch System

Update & Clarification on Metro Launch System

I need to add some more information to what I said earlier about Larry doing a re-design of the metro launch system. While it is true that he is in the process of re-designing the Metro Launch System for the Super Sky Cycle that I am building and the new system will use a shaft drive rather than the belt system, and a side benefit will be less complexity and more head room in the top of the fully enclosed cabin that will eventually go with the Super Sky Cycle, that was not the original reason for the design change. The original and main reason for the design change is that the Rotax 912 engine that the Super Sky Cycle will use, turns the opposite direction and the current Metro Launch System he has developed for the Monarch with a Rotax 503 will not work with the Rotax 912S.

So to not confuse the issue the Super Sky Cycle with the Rotax 912S will have the newly designed Metro Launch System with a shaft drive. All the other single place models that don't use the Rotax 912 engine will still come equipped with the current belt driven version of the Metro Launch System. Both systems will pre-rotate the rotors to over 300 RRPM and enable the Gyros to get off the ground in about 150 ft in calm no wind conditions.

There are some other projects that I am dieing to tell you all about that Larry has in the development stage but he has told me I talk too much and sworn me to secrecy on these issues until he has them finished and in production. Larry is a cautious person that likes to under promise and over deliver. He doesn't even like to talk about it until it is done and real , but I call him daily and pry things out of him and he lets me in on some of the projects. Anyway since I have been sworn to silence for now, you will have to be patient a little longer but I will tell you he has some incredibly innovative ideas that he is building into his machines and I can't wait to have them. It is going to be sooo... cool!!!!!

Keep your rotors up!!!

Gyro Doug

Resasi said:

Doug a very clear and informative report. With your knowledge of the Butterfly have you been able to examine the various changes made on the Carter copter test vehicle or feel able to comment on the prerotator used on that( or is it the same), rotor and drive prop?

I have become interested in autogyros through seeing this one and the big prototype, and am very keen to see what experts in the field have to say about his developments.

Click to expand...

Leigh,

Sorry I took so long to answer your question. I didn't see your post for some reason until today when I was adding an update to this thread anyway.

To answer your question the Carter Copter Prototype started out as a Monarch Butterfly but it has been greatly modified. They developed their own shaft drive pre-rotator, their own Rotor with weighted ends and a variable pitch capability, and their own propeller (also with changeable pitch). Those systems are all very high tech and proprietary to the Carter Aviation Company and were done in order to have Jump Capability (which it does very well) However there are some downsides to their approach and the high inertia rotors have some disadvantages when it comes to control feel and maneuverability.

Larry has taken a different approach and his machines are not capable of Jump takeoff. However they can get off the ground in under 150 feet so they have a really short takeoff (almost as good) without any of the sacrifices the Carter Company has had to make with fly ability. He uses a different approach to create the same landing capabilities that the Carter Company did with their smart strut and has made it available in a package that you can get today, rather than a promise that someday it may be available on the market.

All in all, even though they came from the same birth place, the Carter Aviation machine and the Butterfly Monarch are 2 very different machines.

Hope that is helpful!!!

Gyro Doug

G'Day Doug

Sworn to secrecy, very good.

The vid on the website 'takeoff mls' is 80 degree F with a 5 mph headwind. 325 rrpm at just over 6000 rpm on 582 Rotax Monarch fully dressed and optioned.

The Monarch is off the ground in the space of the Piano Keys, what's that 10 yards? Even nil wind 150 feet~45 yards approx.......150ft is conservative, must be referring to a grass strip there Eh!

Mitch.

Just trying to under promise.

Just trying to under promise.

Greg,

I know it can do better than I stated, but I'm trying to be more like Larry and be real conservative with what I state. It does make sense to under promise and over deliver. It makes people feel great when something exceeds their expectations so setting a reasonable set of expectations in the first place makes a lot of sense.

I'm glad we are on the same team. Isn't this a great world where we can pursue of own dreams and goals and share them with people half way around the world? I don't know if I will ever make it down under, but it feels great to know that if I did, I have mates there that I could stop and visit.

Keep the rotor side up!!!!

Gyro Doug

G'Day Doug,

Larry has a great group of people around him. You would always be welcome in this 'neck of the woods'.

I agree sometimes understating is good. However in this case Larry has definitive video footage, showing the true capability of MLS for the Fully Dressed Monarch.

Looking forward to more pics Doug.

Cheers.

Mitch.

Thanks for that reply Doug. As I mix more with the gyro crowd where I am learning I am beginning to get a feel for what is out there to fly what may be out there in a little while and what may be practical for me to get in terms of affordability. In the meantime having a blast learning how these things fly.
I have found out that sitting around waiting for decent weather is back, and that I can drive for a couple of hundred miles wait all day and still not get to fly. However when it comes it is great.