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Model Forum / Radio Controlled / Air Models / May 2004cant stop superstar ground looping
I have an electric superstar .. tail dragger when i try to launch, it just insists on turning one way or the other .. sharply anything that might help prevent this Keep enough up-elevator in it to keep the rear wheel steering until you have more airspeed. Many taildraggers hae this problem. -- Paul McIntosh http://www.rc-bearings.com > I have an electric superstar .. tail dragger > > when i try to launch, it just insists on turning one way or > the other .. sharply > > anything that might help prevent this >Keep enough up-elevator in it to keep the rear wheel steering until you have >more airspeed. Many taildraggers hae this problem. Also, do not apply full power all at once. Get the plane moving on low power so that the rudder is affective then continue to ad more power as the plane picks up speed.. You can then guide you plane streight down the runway good luck Gene. Also - check for "toe-out" on the main gear. Not alot - just a tiny bit. If you check - I'll bet you dollars to donuts you have toe-in. Regards, >Keep enough up-elevator in it to keep the rear wheel steering until you have >more airspeed. Many taildraggers hae this problem. >Also - check for "toe-out" on the main gear. Not alot - just a tiny >bit. If you check - I'll bet you dollars to donuts you have toe-in. >Regards, Don't you mean the other way around? A very slight Tow-In will get the plane to steer back into a straight line. Think of the plane rolling slightly to the left during take-off due to "P" factor, or torque. More weight is now on the left wheel than the right. Before you can get enough right rudder into the yaw it back on line, the plane will turn the direction the wheel is tracking. Tow in will automatically track the plane back on line. Contrary to what is said before, I like to not like to give up elevator to get the tail wheel to stay on the ground, as it doesn't do anything on the grass when the grass is much taller than the wheel. I get the tail up and steer with the rudder on roll-out. -Fritz No, the first post was right, you want toe-out! Only a small amount, about 1 degree is plenty once the slop in the wheel's axle is taken into account. You can check this with two straight edges placed against the rims of the wheels and extended out to the front of the aircraft. Twist the wheels so it takes up the slack and you should get a little more distance between the ends of the sticks compared to the distance between the wheels. This might give up to 5 degrees at the other extreme as the wheel is twisted the other way due to slop of the wheel on the axle. As long as it is toe-out all the way it will be easier to taxi and control. If the wheel centre is really sloppy change the wheels. Try a google search on rec.aviation.homebuilt and probably several other groups as this toe-in/toe-out has been done to death over the years. Once the wing starts to tilt, you want the wheel that has a little contact to pull the plane back to level. This will at least keep the plane flat on the ground rather than with the wings tilted over at a wild angle. There is no prop blast hitting the ailerons and they have almost no effect where the rudder and elevator have a bit of prop blast giving them some effectiveness. Don't give the motor fast changes in rpm, but let it wind up gradually. You don't need to do short field takeoffs on most of the strips that you will fly from until you have lots of experience. Remember you do not have independent wheel brakes which are a luxury on a real plane that allow much easier control on a taildragger. Most modern taildraggers that have a tailwheel instead of a skid have brakes on the main wheels, where the early models with skids could pull back on the elevator and slow the arse down by dragging the skid. Think back to the WW1 aircraft that took off from a paddock into the wind rather than modern runways that always have a bit of crosswind. The main reason for having a tailwheel is so you don't wear out the taxiway at the airport, rather than having to replace the end of the skid occasionally. They can also give a great shower of sparks when landing on a concrete runway.......... Just remember it takes a lot of praktis, praktis, praktis, beofre you get it rite! Hope this helps, Peter > >Also - check for "toe-out" on the main gear. Not alot - just a tiny > >bit. If you check - I'll bet you dollars to donuts you have toe-in. [quoted text clipped - 15 lines] > > -Fritz >when i try to launch, it just insists on turning one way or >the other .. sharply Use larger, softer tires. Move the LG back. Apply power slowly. Use the elevator yo keep the tail on the gorund until you build up plenty of speed. Dr.1 Driver "There's a Hun in the sun!" > when i try to launch, it just insists on turning one way or > the other .. sharply > > anything that might help prevent this Aply full power and full up elevator to get plenty of wash over the rudder and too keep te tail on the ground. Once you start moving, ease up on the elevator and throttle or you will, depending on model, end up in a vertical climb > > when i try to launch, it just insists on turning one way or > > the other .. sharply [quoted text clipped - 5 lines] > elevator and throttle or you will, depending on model, end up in a vertical > climb Welcome to the world of taildragging. Use some right rudder as you open the throttle. Got to be proactive, here, and anticipate that left-turning tendency when you open the throttle. Too much rudder will make it turn right. Taildraggers are inherently unstable on the ground and are a lousy way to learn to fly models and a great way to learn to fly full-scale. Dan > Taildraggers are inherently unstable on the ground and are a lousy >way to learn to fly models Nonsense! A properly set-up taildragger is easy and a joy to take off and land. You have no worries about digging the nosegear in and constantly realigning it. The linkage is usually much simpler to set up on a taildragger. I fly a Fokker Dr. 1 (considered to be one of the worst ground-handling planes), and have very few problems with it. Dr.1 Driver "There's a Hun in the sun!" >> Taildraggers are inherently unstable on the ground and are a lousy >>way to learn to fly models > >Nonsense! A properly set-up taildragger is easy and a joy to take off and >land. Although it is entirely possible to make a taildragger handle nicely, that does not change the fact that the design is inherently unstable. The main gear is located in front of the CG, which will cause a turn to generate forces that will want to tighten the turn. Have you EVER seen a nose-wheeled plane ground loop? I have not.  SignatureHelge Wunderlich Please remove obvious part of address to send mail >Have you EVER seen a nose-wheeled plane ground loop I never said I did. However, I HAVE seen a firewall torn out when the novice forgets to flare. There are positives and negatives to both systems. Neither is "better" than the other. It's all a matter of proper setup, practice and personal opinion. I strongly favor taildraggers myself. Dr.1 Driver "There's a Hun in the sun!" >>Have you EVER seen a nose-wheeled plane ground loop > >I never said I did. I never said you said you did ;-) >However, I HAVE seen a firewall torn out when the novice >forgets to flare. There are positives and negatives to both systems. Neither >is "better" than the other. It's all a matter of proper setup, practice and >personal opinion. I strongly favor taildraggers myself. Yes, it essentially boils down to personal taste. However, Dan said that the taildragger design is an inherently unstable design, and you called his statement nonsense. THAT is where I disagree with you. Dan is correct: The taildragger configuration IS inherently unstable, and needs proper setup and practice to even work at all. The nose gear design, on the other hand, is inherently stable. Just gun the throttle and steer where you want to go. No need to worry about rudder size, main gear location (within reason), toe in/toe out, gentle use of throttle, proper use of elevator or any other details. SignatureHelge Wunderlich Please remove obvious part of address to send mail >The main gear is located in front of the >CG, which will cause a turn to generate >forces that will want to tighten the turn. Think Corvair ! with the engine slung behind the rear axle, and the resulting oversteer is a tight turn. In a taildragger you want to keep as much inertial mass *ahead* of the axle as is practical. If the axle is too far forward, there's more inertal mass behind the axle, which increases proneness to groundloop. (Don't ask how i know.) Bill(oc) > From: Helge Wunderlich <helgeww.spamtrap@start.no> > Organization: Tele2 Norway AS Public Access [quoted text clipped - 3 lines] > > Have you EVER seen a nose-wheeled plane ground loop? I have not. I have seen "nose-wheeled planes" go all over the field trying to take off. Most never make a ground loop because the first sharp turn jams the prop into the runway and kills the engine. The same thing happens on rough landings with trikes. The nose wheel creates so much drag on a grass runway that much more power is required to attain to take off speed. This also makes the plane much harder to keep straight down the runway. Most novices show up with a trike because that's what the dealers sell. I guess the manufacturers really believe that most of us fly off of a nice smooth asphalt or concrete runway. That's certainly not the case around East Texas where most of us have to fly off grass and not too smooth at that. Almost everyone around here eventually converts to a tail dragger sooner or later. > > Taildraggers are inherently unstable on the ground and are a lousy > >way to learn to fly models [quoted text clipped - 7 lines] > Dr.1 Driver > "There's a Hun in the sun!" Agreed! Trikes are easy to take off but more difficult to land than a taildragger. That nosewheel hitting first... bounce, bounce, bounce... Every model I have is a taildragger (even some that were supposed to be trikes). Morris If you don't mind me butting in here, could you please explain what you mean by a tail dragger? That is, do you mean one that has a steerable tail wheel or just a skid? David PS Is there any inherant problem with a steerable tail wheel instead of a steerable front wheel? Or is that difference what this thread is about > Agreed! Trikes are easy to take off but more difficult to land than a > taildragger. That nosewheel hitting first... bounce, bounce, bounce... > Every model I have is a taildragger (even some that were supposed to be > trikes). > > Morris Yup. Nose draggers have the steering up front where it can get broken.. . > If you don't mind me butting in here, could you please explain what you mean by > a tail dragger? That is, do you mean one that has a steerable tail wheel or [quoted text clipped - 11 lines] > > > > Morris > what you mean by >a tail dragger? Taildragger is otherwise known as "conventional" gear. It can have a tailwheel, skid, or any other device at the rear of the fuselage. A plane with a nosewheel is a "tricycle" gear. Dr.1 Driver "There's a Hun in the sun!" I like tail draggers cause I'm lazy and don't want to hook up the nose wheel!!! Less trouble for me. Eddie Fulmer PS if you're landing on the nose wheel you ain't doing it right!! Taildraggers are inherently unstable on the ground and are a lousy > way to learn to fly models > > Dan Although it is entirely possible to make a taildragger handle nicely, that does not change the fact that the design is inherently unstable Since when?????? Dont blame the taildragger.......blame the operator. All my models are taildraggers and i love em. Never had a problem taxing or ROging. My simple advice for this: PRACTICE!!! > Welcome to the world of taildragging. Use some right rudder as > you open the throttle. Got to be proactive, here, and anticipate that [quoted text clipped - 4 lines] > > Dan Since When??????? Do not blame the taildragger.........but blame the operator operating the taildragger. All my models are taildraggers and I have no problems with them. So take some simple advice: PRACTICE!!!!! I agree!! They had taildraggers long before tricycle gear was commonplace. It's true that they have a tendency to ground loop since the cg is behind the landing gear. It just means that you have to be more careful when flying them. BB >> Welcome to the world of taildragging. Use some right rudder as >>you open the throttle. Got to be proactive, here, and anticipate that [quoted text clipped - 9 lines] > and I have no problems with them. So take some simple advice: > PRACTICE!!!!! > I agree!! They had taildraggers long before tricycle gear was > commonplace. It's true that they have a tendency to ground loop since > the cg is behind the landing gear. It just means that you have to be > more careful when flying them. > > BB Taildragging just make learning to fly models a bit harder. My son started out with a trike, and then converted it to a taildragger whan he got proficient with it. Now that's all he builds. Trikes have been around just about as long as taildraggers. The first airplane ever to fly in Canada was a trike, in 1909. Taildraggers were so popular for many years because of the rough airfields available to pilots; many nosegear airplanes don't do so well on such surfaces. Now we have stronger, better-designed nosewheels that can take more abuse and are resistant to noseover. But I still prefer to fly taildraggers in my work and play. I'm a flight instructor and aircraft mechanic; our students learn better in taildraggers than trikes, but then flying full-scale for the first time is easier than RCing for the first time, especially considering the extensive ground training that takes place first. And things happen more slowly. Dan > Taildragging just make learning to fly models a bit harder. My son > started out with a trike, and then converted it to a taildragger whan [quoted text clipped - 13 lines] > > Dan I started with taildraggers and tried out one trike.....but I find landing the trike in grass sucks. The front wheel will bite in the grass and a nice landing turns into a backflip.....on a hard surface its fine. My taildraggers I can ROG from grass with ease and land. As for my trike......it has floats now and makes a nice little "pond jumper" Mike > I started with taildraggers and tried out one trike.....but I find > landing the trike in grass sucks. The front wheel will bite in the [quoted text clipped - 4 lines] > > Mike We teach a technique in full-scale called "soft/rough" takeoffs and landings. I taught it to my son when he flew his RC trike, and he had no more grass drag problems. On takeoff, full up-elevator is applied as the throttle is opened. The nosewheel will come up if the airplane is set up properly, and the pilot adjusts the elevator to keep the nosewheel just off the surface as speed builds. This will require less and less elevator input. The airplane will fly off when it's ready, without further nose-up (or "rotation," as we call it) and climbout is normal. In some cases the airplane can lift off at very low speed, and after liftoff the airplane is held very low to the ground in ground effect to build speed for the climb. If the airplane has flaps, 10 or 20 degrees will aid greatly. A soft-field landing involves a low approach speed and a nose-high touchdown using some power, After touchdown, the nose is held off with the elevator while power is reduced gradually. The risk of noseover goes way down using these techniques, and you'll be surprised how short your airplane can take off using them. As I've said before, some private-pilot groundschool would make better RC pilots. There's a whole world of information out there, and it would be a great way to spend a few winter evenings. The applicable subjects would be Principles of Flight, Weight and Balance, a bit of Weather, and Maneuvers such as climbs, descents, turns, stalls, spins and the rest of it. You wouldn't need Air Law, Navigation or the rest of it. You can fly the airplane, but do you know WHY it behaves as it does sometimes? And how to avoid doing that again? Problem is to find a school that doesn't charge so much. Dan > Problem is to find a school that doesn't charge so much. For the price of an hour of rider-scale classroom time, one could take SWMBO out for dinner and have enough left to snag a copy of "Stick And Rudder". > I agree!! They had taildraggers long before tricycle gear was > commonplace. It's true that they have a tendency to ground loop since > the cg is behind the landing gear. It just means that you have to be > more careful when flying them. > > BB Take a trike and a taildragger and put them side by side....take away there nose gear and tailwheel and leave the main gear, what do you have???? A seesaw with the main gear acting as the fulcrum. So setup is very important to both. Anyway, ground handling is important but whats more important is the planes handling in the air. And that nose gear = drag compared to the little tailwheel. Mike If you have retracts.....its a different story ;-) > Taildraggers are inherently unstable on the ground and are a lousy > way to learn to fly models and a great way to learn to fly full-scale. > > Dan Although unstable on the ground, taildraggers are great fun and eminently controllable with practice. I trained on glow taildraggers (modified Tucano OS52 4-stroke?) and have only had 3 tricycle u/c planes (H/W Trainer and 2 lge Tucanos w 90 2-stroke) compared to 7+ 'draggers (H/W trainer, 4 mid-wing sports (46 2-strokes), 3 R.O.G'ing electric parkflyers: GWS Beaver, Kyosho Spree Sport, Wingdragon. Tricycle u/c is like driving a car - 'dragger is like flying a Spitfire (watch that swing!). You need a little toe-in for stability. A steerable tailwheel (attached to rudder) is nice but not always needed. Start with a little right rudder and up elevator (to avoid nose-over) as you overcome grass resistance. Throttle up gradually to minimise torque/swing effects. Let elevator go neutral as you build speed. Small timely corrections with rudder are important - so relax those thumbs. Big late overcorrections make ground loops. The plane may lift off with neutral elevator... otherwise apply gentle up. It's also very important to take off and land into the wind. http://www.pipercubforum.com/topcub.htm -the pros and cons "And then there is the dreaded TAILWHEEL! Can it be mastered? Will the airplane willfully ground loop the instant it is untied? Can only super-beings fly airplanes so equipped? What a crock! We forget that the nosedragger, taildragger controversy didn't even exist until the 152/172/Tri-Pacers became prevalent enough as trainers that a generation of pilots was born with dead feet. Every pilot before them just took the taildragger for granted. That's the way airplanes were, so that's the way they flew them. Today, there are enough tailwheel schools and instructors that getting training isn't that difficult. Depending on the individual, figure about six hours average to transition with another couple of hours of post-solo dual spent working in nasty crosswinds as insurance. There is no magic to the tailwheel. All it requires is some of the basic skills you were supposed to develop in the first place and, once you've become comfortable with the tailwheel, you'll discover an entire new world open to you." from http://www.airbum.com/articles/Article.BuyClassic.html SignatureMark Lee > > Taildraggers are inherently unstable on the ground and are a lousy > > way to learn to fly models and a great way to learn to fly full-scale. > > > > Dan > > > ... You need a little toe-in for stability. ... Toe-in will add instability in most taildraggers. As the swing begins, the weight will shift toward the outside wheel, and if it's toed inward the turn will tighten and increase the rate of swing. Toeing the wheels out a bit can help reduce the instability, but the best practice is no misalignment at all. I used to fly a Champ that had a misaligned left main. It was turned in a bit, and the net result was some overall toe-in. I had to touch down with the nose cocked left about three degrees to get the line of travel symmetrically between the wheel tracklines so it wouldn't leap to the right on touchdown and try to go squirreling off the pavement. Even then I had to pay special attention to prevent ANY swing. Grass was easier. Other Champs and Citabrias I have flown had their wheels properly aligned and didn't have the bad behavior. The wheel alignment on the old Champ oleo gear required bending the strut to straighten the wheel so it often was left alone and tolerated. The newer machines have spring gear and shims to adjust alignment. Misaligned gear on the big Cessna taildraggers can be exciting indeed. Models usually just require bending some wire, but the slop in the bearings and the easily-twisted wire can make the wheels do their own thing anyway during ground ops. Dan I've had two planes with this problem. One was a cub and I solved the problem by setting up a "dual rate" rudder with very little throw. The other was a three channel top flite elder. The rudder on this plane is so small that it has not authority at slow speeds. I doubled the size of the rudder and it did fine. It had problems landing because of the small rudder once the plane slowed down to landing speeds the rudder was useless. Again this was solved with the larger rudder. > From: not_today@nowhere.com (Mojo) > Organization: Your Company [quoted text clipped - 8 lines] > > anything that might help prevent this |
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