RE: Gyro with a Heli Head?
It's quite possible: http://www.rcuniverse.com/forum/m_2325673/tm.htm www.mickeynowell.com You will generally need much bigger blades than the heli had. For example on mine the original heli blades were about 12" and the gyrocopter blades are 16". You may want to make a longer flybar since the RPM is lower and you will want to get the control response back up. In any event it makes a very stable gyro. I tried collective pitch on one and it doesn't add a whole lot, but if it's easy to keep, leave it on and use it to fine tune the pitch settings. Good luck.
Posted on: 2/27/2009 10:55 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=8524231

RE: 4 Bladed Teeter Head
Someone already did this, but I can't find the link. Four bladed teetering is really hard to to because the two blade systems have to interlock but not touch each other. It doesn't really have any advantages as regular flapping hinges do the same thing on a 3 or 4 blade head. Teetering really only makes sense on two blades. Blade area is not that critical, I'm flying a 1 pound model with two little 1.5" x 16" blades and can fly fast and slow....
Posted on: 7/21/2008 7:57 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7756698

RE: Robbe Whopper
All accounts of the whopper was that it was fast, heavy, and needed a lot of power to even fly. My vote would be to make a nice display out of it and buy something that's being manufactured right now.
Posted on: 6/11/2008 4:56 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7608194

RE: "Dihedral" or preset coning effects on rotor
[quote]ORIGINAL: John235 Now you mention it, I can see that 90 degrees phase shift is the going to prevent coning from helping stability. That answers the question I wrote about. Thanks! [/quote] You're welcome. [quote]ORIGINAL: John235 After acknowledging the tendency for the path of the rotor blades to tilt backwards due to the incoming airstream, [/quote] This is the critical knowledge, once you get this, things make sense. [quote]ORIGINAL: John235 If I have my thinking straight, this roll-to-yaw coupling should allow the autogyro to make turns using rudder only, without the need for lateral cyclic control. [/quote] This is true in theory, but the rotor response to this takes a long time, longer than a human finds comfortable. This is why the jump from a two rotor to single rotor is so dramatic for the pilot, the dual rotor self corrects because the rotors are set with dihedral with respect to each other and correct. This single rotor does not and demands constant attention to stay level. What you effectively have is a very sluggish control system that works under ideal circumstances, but fails to provide emergency maneuvering power, resulting in a crash. Virtually all the yaw controlled single rotor gyros also have a significant lateral surface and turn by skidding rather than rolling. You get some roll but it's likely due to the vertical surface being above the CG causing a roll, not the rotor's response to the yaw. Keep in mind that due to aft tilt of the rotor, yaw causes a cyclic input to the wrong side. The inward tilt of dual rotor models corrects for this so that when the rotor is yawed it introduces nose up cyclic on the forward yawed rotor to make it provide more lift, thus generating the desired roll response. As an aside that rotor will also speed up and thus make the model overshoot in roll, thus producing the characteristic dutch roll like behavior of the dual rotor models.
Posted on: 6/6/2008 10:12 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7587400

RE: "Dihedral" or preset coning effects on rotor
[quote]ORIGINAL: John235 Where in the quote did Cierva refer to the coning of the autogyro? It appears to me that the quote refers to the use of flapping hinges, rather than coning. I haven't read Cierva's book, but I believe the flapping hinges were required to solve the problem of lift dissymmetry, not to deliberately increase coning. [/quote] He didn't. We hashed this to death on RCGroups. Coning has no advantages. It doesn't provide yaw/roll coupling, nor does it create any stability laterally or longitudinally. [quote]ORIGINAL: John235 My view of this issue is that flapping hinges have several advantages. Mainly it works as a type of stabiliser to regulate the dissymmetry of lift. Dissymmetry of lift can be solved with cyclic controls but I believe that some form of blade articulation (flexible blades, flapping hinge, head damping or teeter hinge etc) is still needed to for reasons such as stability, to reduce vibrations, and to reduce the control forces. I don't think there is really any dispute about these benefits. [/quote] This is all true, and as you point out it has nothing to do with coning. [quote]ORIGINAL: John235 The advantages of coning is where the disagreement seems to be. There are obviously some disadvantages, but there may also be advantages. One thing that is totally clear to me is that coning does not provide yaw-to-roll coupling in the same way that dihedral does on model aircraft without ailerons. The question in my mind is how coning affects longitudinal and lateral stability of rotorcraft. It occurs to me that coning will increase stability on these two axis, which is similar to the use of dihedral to increase lateral stability on full size aircraft. I think its possible that stability provided by coning could be a help with model autogyros that do not use cyclic control. I expect the mechanism for yaw-to-roll coupling in autogyros without cyclic control has a more involved explaination than what I would consider as common sense. [/quote] The disagreement is from those that don't understand how dihedral works on an airplane in the first place and that it works by virtue of yaw/roll coupling. Since the yaw/roll coupling on a rotor is 90 degrees out of phase it can't possibly work like dihedral.
Posted on: 6/6/2008 7:56 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7586992

RE: Ultra Micro Gyrocopters on You Tube
Umm... Where have you been? There are already many clones of this flying. all kinds of discussion, sources for radios, foam here: http://www.rcgroups.com/forums/showthread.php?t=781538
Posted on: 5/16/2008 10:51 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7503171

RE: Roll T/O question
I've had pre-rotators on my kits for years now. 100% reliable takeoffs, 10 to 20 feet with no hassle, max performance takeoff in 5 feet. Crosswinds or no wind not a problem. You can taxi out like everyone else and just takeoff, no walking on the runway, hand spinning, etc. I think everyone should do it. Videos of pre-rototated takeoffs here : www.mickeynowell.com
Posted on: 5/15/2008 5:32 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7500411

RE: Gyros for airplanes
Try posting this question in the 3D airplane forum. This forum is for gyrocopters not gyroscopes.
Posted on: 4/8/2008 9:29 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7353798

RE: LakeLand Autogyros
[quote]ORIGINAL: AeroBalsa Mike Jim, It would be great to come down next year and get a break from the c-c-c-c-c-cold weather up in Chicagoland this time of year. [/quote] Yea it got cold this weekend, I think it got down in the 50's.. Brrr...
Posted on: 3/17/2008 9:53 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7241252

RE: LakeLand Autogyros
Thanks to all. I had a good time. Thanks again Jim for arranging the event, we had plenty of time to fly. Phil's new creation really flies well. Jim did his duty by getting many models trimmed out. Let's do it again, maybe at a time when the crew from up north can come down and make it a real big event. Maybe we can build a trainer for newbies to try. mickey
Posted on: 3/17/2008 6:22 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=7237308

RE: March Autigyro's Lakeland, FL
i'm in. mickey
Posted on: 12/10/2007 9:33 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6740844

RE: Wind Tunnel Tests of Autogyro Rotors Article
Nice report. One consideration is the size of the model. Mine are smallish and the Re varies from about 50000 to 150000 root to tip, with the 2/3 radius Re being about 100K, depending on RPM. At this size I believe surface finish is as important, if not more important, than the differences in profile. The 6043 looks lousy at Re 100000 ( up until Cl 1.2) but at Re 200000 the 6043 has a better L/D above 1.0 than the rest. This may be important at a high load factor in a gyrocopter. When the other profiles are starting to develop high drag at high Cl this will cause the rotor speed to decay, whereas the 6043 would maintain rpm. This kind of behavior probably doesn't factor into a profile choice for a fixed wing aircraft but may be especially important in a autorotative state at a high load factor. As the load or AOA increases the 6043 L/D increases steadily out to a Cl of 1.2, the 7043 has a better max L/D but peaks at Cl = 0.5, so as the AOA increases above that point the rotor speed will tend to decay, not increase. Worse still, at Cl max the L/D of the 7043 is half the 6043. If you are building a UAV or piloted aircraft the profile selection may be driven more by rotor RPM margin than max L/D performance. I think in a high G situation you'd rather have the rotor speed remain constant or increase rather than decay. If the RPM decreases when you turn, you will of course have to add power to maintain altitude in the turn and because the rotor RPM lags, you will need to add power in advance of a turn to avoid a altitude dip entering the turn, then reduce power before exiting. If you design around the 7043 at optimum L/D of 0.5 for the cruise condition, then every time you execute a maneuver the rotor will decelerate. If what you are after is a long cruise, maximum duration then you may accept that side effect, but if you intend to maneuver, then having the rotor RPM decay for each turn may be annoying or dangerous. At the maneuvering limit (like an emergency situation) I'd rather have the 6043 any day. Since the lift is a function of velocity squared maintaining rotor rpm is a critical issue. If you establish the borderline auto-rotative state for all profiles at Cl = 0.5 any increase in load/AOA of the three "good" profiles will destroy the auto-rotative state, but the 6043 will maintain an auto-rotative state all the way out to Cl = 1.2. If its my A** in the seat I'd be more comfortable knowing the rotor will keep turning if I have to maneuver in an emergency. Essentially if the delta L/D wrt alpha of the profile is positive around the cruise point the rotor will accelerate when incrementally loaded and conversely if the delta is negative, the rotor will decelerate when incrementally loaded. Might be something to consider for a man carrying application or a stable sensor platform.
Posted on: 12/7/2007 9:02 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6725343

RE: Wind Tunnel Tests of Autogyro Rotors Article
I think I have hardcopy of the article. I think I also have a hardcopy of the actual windtunnel data as well. I'm an engineer as well, so I might be able to poke around and find a quick answer if you need it without having to copy the whole pile. Edit : I lied. I can't find the RCM article, but I did find the test report from Bill f. from April 1995 when they tested various rotors, but it doesn't mention the airfoil in question. Must have been a later study.
Posted on: 11/28/2007 8:08 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6687571

RE: Rule of Thumb for Gyro Electrics?
Bill, I think your numbers are a little aggressive. You can do pretty good 3D flying on 100 watts/pound. 50 watts/pound works for sport flying. I have a cub that flies scale like, including loops and rolls on about 55 watts per pound. My Gt17 flies fine at 19ounces with around 90-100 watts full throttle for loops, and 1/2-3/4 throttle for climb and cruise. My rule of thumb is about 75 watts/pound for small electric gyrocopters. mickey
Posted on: 11/5/2007 9:11 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6582867

RE: G3PO and BEGI parts questions
If it works then there is no reason not to use it. I don't know if it's long enough when you fit the pre-rotator. If you are using it in that case let me know. Basically any 3mm shaft with the 1mm hole in the proper place will work.
Posted on: 7/22/2007 12:51 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6141777

RE: G3PO and BEGI parts questions
I don't think it's long enough. Besides you have to cut the gear off.
Posted on: 7/21/2007 4:29 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6139013

RE: G3PO and BEGI parts questions
For main shaft I use these: http://www.bphobbies.com/view.asp?id=V019752&pid=NESKV029 You have to trim a few mm off the end so if will slide in far enough to have the hole line up. For a flybar use 2mm (0.078) music wire, 290 mm long. They fly about the same. G3PO has better ground handling and is better for rough/unimproved fields. mickey
Posted on: 7/21/2007 12:43 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=6138439

RE: Kellett to Pitcairn
Thats very cool Jim. I'll have to drive down and see it fly sometimes.
Posted on: 6/14/2007 11:41 AM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5986674

RE: Now flying successfully with a teetering head
Congratulations. How much blade weighting is used? Are they CG corrected? mickey
Posted on: 5/15/2007 3:49 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5858561

RE: AutoGyro's at SEFF
I know I had a good time. I was really impressed with Jim ripping GT17 around in that wind. Hippo had a rotorshape also, he was kind enough to let me make a flight (at dark!). Hippo's new design flew after we changed a few angles, but it looked good in the air. RL was there with his whopper as well. Doug brought a G3PO for me to check out as well, but it wasn't quite ready to fly. By my count we had 4 G3PO's, a BEGi, 2 GT17's, A rotorshape, a whopper and Hippo's new model. No hanger queens either, everthing flew at least once. Great fun, we need a bigger gyro contingent next year.
Posted on: 4/30/2007 11:10 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5794705

RE: New AutoGyro
Hacker A20-20L 20 amp speed control 3s lipo 2100's or 2070's
Posted on: 4/22/2007 7:20 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5754227

RE: Large Scale Helicopters-25Kg Payload
Yamaha RMAX is about the only game in town. http://www.yamaha-motor.co.jp/global/industrial/sky/index.html
Posted on: 4/22/2007 1:51 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5753056

RE: Prerotator devices
Here's my pre-rotator wiring diagram in anyone is interested. Might save some headscratching if you are experimenting. see you at SEFF mickey
Posted on: 4/19/2007 4:58 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5740807

RE: Prerotator devices
[quote]ORIGINAL: C-124 Flt Engr Micky- About full scale pre-rotate and jump takeoff: Don't overlook the Umbaugh U-18. I worked on the drafting board and was involved until Type Certification around 1960. It was my only, and no doubt the last, full scale Autogyro ride! Ron [/quote] Thanks. I knew there were others, like the Pegasus, just couldn't recall in the heat of the moment. I was just trying to make the point that the need for pre-rotation wasn't simply my idea but was fairly obvious to almost every autogyro designer. Didn't the the U-18 turn into some other name? Check out the pegasus. I wonder if they'll ever make some more.... http://www.pegasusrotorcraft.com/
Posted on: 4/17/2007 9:38 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5732085

RE: Prerotator devices
[quote]ORIGINAL: AeroBalsa Mike What I see as the ultimate challenge in model autogyros is to develop a jump takeoff feature... as in a real vertical takeoff. Now THAT would be something to see! [/quote] You will. Work in progress.
Posted on: 4/17/2007 12:31 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5729374

RE: Prerotator devices
Joel, Let me make sure I understand how you feel: You don't think we need pre-rotators at all. Putting a pre-rotator on is trying to make the autogyro into a helicopter. Autogyros are more fun than helicopters. Anyone that is interested in a pre-rotator is somehow trying to be like Me (instead of like for example : Cierva, Pitcairn, Kellet, Bensen, Brock, Rand, Wallis, Groen, Robbe, Micromold, Kalt, Air Command, Charyair, Little Wing, Magni and Carter Aviation which has jump takeoff as well as prespin) You think I have a "tender spot" because you make something bad out of wanting to be "like Mickey" and I step up to defend myself.. So i'm guessing that you want everyone to shun me like a leper so I'll wise up and quit working on this foolish pre-rotator enabled, swashplate controlled heresy.... Please let me know what I did to [b]personally[/b] offend [b]you[/b]. I'll gladly apologize. mickey
Posted on: 4/17/2007 12:21 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5729327

RE: Prerotator devices
Since being "like Mickey" seems to be part of this thread here's Mickey's opinion. 1) PT gyros are nice machines. I have no beef with FlyingBalsa. 2) The tilting head on the PT has the advantage that you can tilt the rotor head back while taxiing. This greatly aids spinup. 2) My swashplate controlled rigid head doesn't tilt so it is more difficult to spin up by taxiing. The pre-rotator makes up for this. 3) You still have to hand spin the PT, according to Joel and all my observations. This is no big deal but does deny you the ability to taxi downwind to the end of the runway turn around and takeoff. The pre-rotator allows this, just as Phil has mentioned. This improves the respect my gyrocopters get at the field and at airshows. Besides, it's fun. At my field they get all hinky if you walk out into the runway. 4) I developed the pre-rotator for BEGi which is a tall, short pusher. It can be challenging to takeoff in a crosswind or dead calm. The pre-rotator makes this model fun to takeoff in any situation. 5) With pre-rotation I can mix it up with the other models on the field and takeoff down the pavement without having to go directly into the wind. Not all of us have a big field all to ourselves. The wind is always cross at my field and the runway isn't that wide. 6) With pre-rotation I can fly indoors in a basketball court in dead calm. 7) In completely dead calm conditions I can clear a 6 foot obstacle 10 feet in front of the model. (there is video of this on my website) I can takeoff downwind with no problem. I can takeoff from a picnic table on a dead calm day. I don't care how fast your rotor spins up while taxiing it won't do these things without some kind of pre-spin. My pre-rotator brings the rotor up to essentially flight rpm. 8) Charlie has a point. The peak of autogyro development was with collective pitch, pre-spin and jump takeoff. There is a commercial gyrocopter now in development with jump takeoff with a video floating around. Don't blame me for pre-spin. I didn't invent it or the need for it. The full sized guys did. I just made it work reliably on my models. 9) Bensen developed pre-spin on his gyrocopters because it provided balance. The aircraft could takeoff anywhere it could land. Before pre-spin he could land in places that he couldn't take off from. This is very clear in his book. With pre-spin I can takeoff anywhere I can land. This does provide some flexibility in where you fly.Most of my kits get sold with pre-rotators, so somebody else sees the need. 10) With pre-rotation I can run flatter pitch and fly slower than I can without it. 11) With pre-spin I can hand launch in a rough field with no wind and no running. Try that without pre-spin. Finally I'm not advocating that you use pre-spin or don't or that you copy me to be "like Mickey" or not. You guys can hash that out amongst yourselves. I have pre-spin because it works, I don't mind it being more complicated and it provides performance that not having it can't match. By all means if you don't think you need pre-spin, don't use it. Phil is probably fired up about pre-spin because for two years in a row he's seen me at Spring Hill, taxi out, spin up and takeoff when everyone else is grounded because of crosswind. Like it or not the pre-spin lets you fly in more situations than without. That's why I like it.
Posted on: 4/16/2007 10:42 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5727185

RE: Prerotator devices
[quote]ORIGINAL: ottogiro58 Hey Phil, You're the man !!! Thanx for sharing the nice prerotator arrangement. Can you give me a ballpark figure for the complete unit, including the replacement spin-up motor and speed control, minus rotor head ?? Thanx !!! Charlie Anderson [/quote] I have kits that are $22, they include the bearing, the plywood mounts, the gear and hardware. You supply a motor ($13) and speed control (~ $25) and a GWS speed 400 gearbox ($1.25)
Posted on: 4/16/2007 10:03 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5726985

RE: Prerotator devices
[quote]ORIGINAL: JoelW Since these are autogyros and are more fun than any helicopter and fly much better, why should we try to be like a helicopter. I've watched many, many helicopters at model flying fields and for the most part unless the pilot is a real pro all they do is hover, hover, hover then wind up in a ball of twisted parts that are very expensive to replace. [/quote] You are certainly entitled to your opinion. However I have 3 gyrocopters and 3 helicopters. They are all fun to fly, none especially more fun than the other. If all the helicopter pilots do at your field is hover and crash then you have a bad sample of helicopter flyers. The ones I fly with, including myself, do rolls, loops, fly inverted and backwards. The neat little blade coax helicopter is really easy to fly and most people can master it in a short time. I don't think there is a need to bash on helicopters just because you like autogyros.
Posted on: 4/16/2007 9:59 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5726967

RE: PTGyro Conversion
[quote]ORIGINAL: floridagyro Once you get into the delta head with all the parts, I'm not sure there is that much difference in total parts count and or much difference in cost. For sure much less weight, due to the feather servos and mounting brackets. [/quote] or assembly time. There is $20 in servo savings alone. I think it comes down to whether or not you want to DIY your rotor head or not. It's pretty clear that some builders take great pride in making as much of the aircraft themselves. Ok for them, but sometimes advancement in the state of the art comes from some new enabling technology. I could have done a swashplate gyrocopter from heli parts a long time ago, it was the availability of inexpensive molded rotor head parts on the Feda/Hummingbird/Dragonfly that made making this kind of design economically possible. I thought that after I had G3PO sorted out that I would go back and make a tilting head design, but I lost interest. The three bladed tilting head design is pretty mature, basically unchanged in design since Emilio's ECDC. I can't see some radical new tilting head design coming down the line, just refinements of the current design. So I'll stick to swashplates, until I can do an electronic cyclic control with servo flaps or something. The electronics are there to do this, just need some tiny actuators.... [quote]ORIGINAL: floridagyro Mickey, what is the motor down thrust and rotor mast tilt back in the G3PO? [/quote] The mast is set at 110° from horizontal (20° from vertical). Downthrust is 0 or 5° depending on the builders choice. The 5° helps it stay level under power changes.
Posted on: 4/10/2007 1:29 PM by Author "mnowell129" in the forum "AutoGyros"
http://www.rcuniverse.com/forum/fb.asp?m=5694187