bgorham

Hi all .... very new to this whole thing so bare with me.

I have a ripmax nova 40 trainer, and have spent the past two months replacing my nosegear after snapping it off every weekend with my pitiful landings. Thanks for the landing tips I was following in earlier post.

My hobby shop guy talked me into switching it to a tail dragger, and I picked up all required parts. Question for the group ... how far forward should the main mount be in relation to the CG?

Thanks for your help .... Bo

MHawker

My Feedback: (16)

Unless you are very confident in your take-off skills, I would be wary about switching to a taildragger. They are much harder to take off than a nose wheel plane. I switched and wished I would have waited a little longer to develop my skills a little more. I had to make a few repairs that I probably wouldn't have had to, due to blown taxi- to- take off mistakes.

As far as where to mount the main gear, you may be able to leave it where it is, depending on the plane. Mount your tailwheel and see how your plane balances.

Mike

MHawker

My Feedback: (16)

oops, repeat post.

Sorry.

Dugster

Sorry MHawker, wrong answer. The mains MUST be in front of the CG. Otherwise the silly thing will keep nosing over looking for the front wheel. The accepted generic position for taildraggers is to have the axles for the main wheels at or slightly ahead of the leading edge of the wing. It doesn't need to be exact. In most cases close is, well, close enough.

TopShelf

My Feedback: (4)

For tail draggers, the wheels are generally set so that that they are even with the leading edge of the wing.

An easier solution is to purch a Fults strut nose gear. This unit will solve all of your problems. Your plan will handle better on the ground and can hold up to the mose severe abuse. I hade the same problem with my trainer and the Fults strut was a much easier solution than converting to a tail dragger and re-learning how to take off and ground handle.

Fults you should be available at your LHS. If not, Tower carries them also.

Billy Hell

My Feedback: (2)

I had the fults and it cured my daily rebuild of the front gear. I'm using a tail dragger now and I really like and didn't have much or any trouble switching.

MHawker

My Feedback: (16)

Dugster,

Thanks for the correction. I'll file that one away for future reference.

Mike

Graham-RCU

I too was getting very frustrated with the nose gear on my trainer.. more with the poor steering that constantly went out of wack.. I converted it (Hobbico Superstar 40) to a tail dragger...moved the gear inline with the leading edge.. and all of a sudden the frustraton was gone and the fun was back in the flying. No problem getting used to the tail dragger.. just listened to our instructors and I was ok in no time..

Good Luck

bgorham

Thanks for the info on the setup. I was playing around with where to put the mains, and was worried about it going nose over or the converse it being too far forward and banging the tail hard on landing.

My poor trainer is a miriad of patchwork already. My wife cringes every time I come home, as I have broken something every time I have flown, and put her in the ground twice! That's why it is a trainer though ... and I am a tough case for my instructor. I tell you what though, this sure is a fun hobby.

One of the best things is, it is a great way of meeting people. I am an American Ex-Pat living in the UK, and it has been tough getting excepted into social scenes. It has been great meeting new friends and socializing with the guys in the club. The only problem is I am being taught to learn to fly in the "proper" British way, and they give me a hard time about wanting to fly on the wrong side of the sky!

Thanks for the info ..... Bo

BingoFlyer

If you are beating the front gear on your trike it sounds to me as though your plane my be nose heavy, I know some say that trainers should be nose heavy but that is not right! Check the balance and remember that a nose heavy plane does not fly well but a tail heavy plane does not fly long!

Norm Nestie

bgorham, I"m sort of new ro RC flying as well and had same problems with nose gear. Switched a Seagull Arising Starto tail dragger and it became a much better plane. Have since converted my Eagle 2 and GP Easy Sport to tail draggers. Just keep CG the same as called for and mount a GOOD landing gear with LE of wing as suggested. I use fiberglass gear. Much better than aluminum. Sure take offs require using up elevator but that is easy to learn. I bolt the gear on with quarter-twenty plastic bolts which usually very nicely sheer off when they have to, saving the fuse. Try it, you'll like it FWIW

bgorham

Thanks everyone for the threads. I moved my mains so the axel is right at the leading edge and I am ready to go run it around on the ground and figure out how to control the thing. The isobars are far to close together to fly this weekend, things are blowing pretty hard out here.

On the question of it being nose heavy, I have the cg right where the mfg sez to put it. My landing problems are 100% me!

Another question, I was browsing through some flight instruction sites and they were talking about mixing the rudder and ailerons for trainers to help coordinate turns. What is the advise on this, is it something that I should consider? My futaba does not have this function, and they were recommending using a y-cable setup in my case. Has anyone tried this?

Again, thanks for everyone's help.

Bo

HarryC

My Feedback: (1)

Bo, two of the people I am teaching at the moment are having the same problem as you, bashing the model in nosewheel first every time. I keep demonstrating how the model should be nose high on landing, how and when to pull back on the stick. When they are landing I tell them "pull back now, NOW" but they still don't do it and whack the noseleg in again. Changing to a taildragger will not solve this because if you are not pulling the nose up, where the wheel is will have no effect. In frustration I have tried a new flying exercise on them which seems to be helping them become more comfortable with pulling hard back to land as trainers need, and their final flare-outs have improved quickly. Fly around at safe height, slow speed at full up elevator - their Thunder Tiger trainer flies quite happily like this without stalling out. It has got them used to and comfy with holding on lots of up elevator and still steering the model, so when they come to the final flare for landing they are used to how it feels to pull hard back on the stick.

Ignore anything about mixing aileron to rudder for co-ordinated turns because it is mostly wrong. Your trainer should not need co-ordinating and if it does need a bit, who cares anyway, there is no-one on board to feel ill. Mixing aileron to rudder only works while you are holding on some aileron and unless your trainer is so ridiculously stable that it keeps trying to roll upright immediately, you will not be holding on any appreciable amount of aileron in the turn. Ailerons can cause an affect called adverse yaw, where you roll one way but the plane yaws the other way, this is worst in gliders which have long spans and hence plenty of leverage to cause the yaw. The effect only happens whilst some aileron is applied, once you achieve the desired bank angle and neutralise the ailerons, the adverse yaw disappears. In this case a small amount of rudder mixed from the aileron can counter the adverse yaw, but this only works during the roll into and roll out of the turn. It can have no effect during the turn where the ailerons are at neutral. It is simply impossible for aileron to rudder mixing to balance a turn since you don't hold on a big enough amount of aileron in the turn to make the rudder move! Should the plane be obviously out of balance during the turn, and you really feel the need to correct it, you will need to use your rudder thumb. Frankly it is not something you need to bother about at this stage.

An aircraft may yaw slightly out of or into the turn, this is called respectively slipping and skidding. Which it does depends upon the speed, the angle of bank, the power setting, the design and so on. In one turn it may slip, in a different turn it may skid. The first needs rudder into the turn, the latter needs rudder out of the turn. Since mixing will only give rudder one way, it can not be of use since it may move the rudder the wrong way for that turn! Only model fliers believe that rudder must be the same way as the turn, full size pilots have a slip ball instrument that shows them which way to move the rudder and they are used to pressing it in opposition to the turn if the slip ball says to. Anyway unless you are holding on an awful lot of aileron during the turn, sufficient for the low % mix to actually move the rudder, you will not get rudder from aileron in the turn.

Welcome to the British weather, don't forget to take your flask of tea to the airfield!

Harry

bgorham

Thanks for the info Harry. I will try the deal about flying with full up elevator, that sounds like very good advise. Thanks also about the flap and rudder mixing. I was looking at www.goflightschool.com and they were making a pretty big deal about doing that especially for a trainer.

Where are you located? I am flying at Langor airfield with the Nottingham remote control society.

Bo

HarryC

My Feedback: (1)

Chedworth R/C Club in Gloucestershire, and fly full size from Staverton Airport next to Cheltenham.

I took a look at that site, it's their opinion but certainly not a common opinion here. They do say it is just to counter adverse yaw, well if you don't suffer from adverse yaw there is no need, and most people that I know find that if they get into the habit of ground steering with the aileron stick they have to unlearn it to ground steer correctly with the rudder.

Harry

Dugster

Bo,

Just had another thought while re-reading this thread. How much elevator throw do you have set up? If you're set at the minimum try adding a 1/4 in. more in both directions. I discovered this when learning myself. As I got more confident I started adding more control movements on everything. The one I really noticed was adding more elevator made MUCH easier to flare the plane at touch down. All of a sudden I was doing picture perfect landings.

bgorham

Thanks Harry and Dugster for your responses. Harry, I will stay away from mixing the ailerons and elevator, just thought that was an interesting article, and something that no one had mentioned.

Dugster, I hear what you are saying on the throws. Mine are set up to the instructions that came with my airplane.

I just wish the winds would calm down a little bit so that I can practice some of these tips. Will let you know how things go.

Bo

MinnFlyer

My Feedback: (4)

Thanks Harry, It's nice to hear someone use a little "Modeling Sense" for a change. Many times I've heard fliers talk about co-ordinating turns, and the plain fact of the matter is: You don't need to! Unless you're flying a huge plane and the adverse yaw is so bad that it's noticeable from the ground and you want your turns to LOOK nicer, or it's SO bad that the plane is unstable in turns, in which case you may just have a bad design on your hands. But it really ticks me off when some "INSTRUCTOR" is trying to impress his student with how knowledgeable he is about flying so he fills the students head with information he doesn't need. I would like to know how many of these people actually co-ordinate THEIR turns.
A few notes back on topic... Bo, did you ever stop to think that what you save in nose gear, you'll spend in props now? But since you've made the change already, keep this in mind... on a tail dragger, you want your main wheels to "toe in" just a little. That is, the wheels should point (very slightly) in toward the nose. This will help reduce a tail dragger's tendency to "Ground Loop" while taxiing.

bgorham

Hey MikeB, Thanks for the note. Yes, I understand my basic problem, and that is failure to flair the plane properly while landing, thus comming in hard in a nose down attitude. I have read the threads on landing properly and now feel I have a good understanding of the theory, but unfortunately have not had a chance to test it out in practice. Unfortunately the guys training with me didn't talk me through the up elevator bit, and have me play around with the angle of attack and nose attitudes. Hopefully I will have a chance to get out this weekend and give her a go.

On the toe-in thing, I was practicing taxing the plane in an empty parking lot near me the other evening, and noticed two things ...
one was the plane ground looping extremely easily, and the other that it always wants to push hard to one side ( I can't remember which side for sure ... probably left?). So the ground looping can be helped by toeing in the wheels (a couple degrees ... around five or so?)

Overall control and steering with the tail wheel wasn't that bad, I noticed the looping only at taxi speeds, when I ran it up faster it tracked pretty well. Is the pushing to one side caused by the effect of the prop pushing the plane? or is my setup way off?

On a plus note, I like the tail dragger look of the boxy old trainer ... makes it look kinda cool! Well anyway that's what my daughter sez.

Again thanks everyone for the help!

Bo

HarryC

My Feedback: (1)

Bo, a taildragger is inherently unstable on its wheels whereas a trike is inherently stable, that's why trainers full size and model prefer trikes. In the full-size world there are flying schools that offer specific taildragger conversion courses. Converting from trike to taildragger is not a solution, it is another extra problem you do not need! A plane is like a dart, no matter which way it starts off there is only one way it is stable and it will flip itself to point in that direction. A trike is like a dart pointing forward, a taildragger is like a dart being thrown backwards and it does its damndest to flip itself the "right" way around. At low speeds where the tailfin has not enough airflow to control the direction, the plane is dominated by the drag of the 2 main wheels. If these are behind the CG as per trike then it will stay that way, if they are ahead of the CG as per taildragger, the drag tries to get behind the weight just like a dart. At flying speed on take off or landing the tailfin and rudder have enough power to overcome this, but at lower speeds the wheels win, especially on landing where the momentum of the weight is trying to overtake the drag of the wheels and the braking effect of the prop is pushing the nose backwards instead of pulling it forwards.

If you are not raising the nose enough on landing, then by removing the noseleg you are asking the prop to hit the ground for you, this is not good for the prop, the engine or the bulkhead!

Flying a model plane is not easy, they are not toys, they are real aeroplanes and there is no magic cure! Practice practice practice!

Perhaps I can help by explaining the landing procedure? The aircraft should be on a steady shallow descent towards the landing point, probably at a lower speed than the one you have been taught to fly around at. Now comes the thing that model fliers seem to find hardest to understand, full size fliers have no problem since the instruments make it starkly clear - a plane's speed is controlled by elevator not throttle. A plane's up or down is controlled by throttle not elevator. There is clearly a cross-over interaction between throttle and speed, and elevator and up/down, but to control the speed you use elevator and to control whether or not you are going up or down at that speed you use the throttle. So to slow the plane a little for landing you have to gently ease on a touch of up elevator, and adjust the throttle to make a gentle descent. At about 1 foot off the ground you start to arrest the descent by using elevator to slowly slowly raise the nose so that the plane flies a gentle curve to be flying level to the ground say 2 or 3 inches above it, at the same time you are closing the throttle. By now you should be slightly nose high, flying along the ground, throttle closed. If the model now touches down, ok, you have already got the nose up a bit. Ideally what happens is that as the speed bleeds off and the model starts to drop you gradually and smoothly pull in more and more elevator to hold it off until it just will not stay up any longer and the main wheels kiss the tarmac. The basis of this is: flare to arrest the descent and fly the plane parallel to the ground, as it slows keep pulling back to hold it off until it stops flying. Don't do this 2 feet up as when it stops flying it will drop 2 feet!

On calm days or evenings it really can be that good, every landing.

Harry

rc-sport

My Feedback: (12)

Bo, 2 things about tail draggers that I didn't see mentioned. First when you convert a plane from a trike to a tail dragger make sure you have good anchor plate for the front gear. I use a plate made from1/4" ply and triangular stock epoxied to the plate and the fuse sides. Use 1/4" nylon bolts to secure the gear, they will break off in hard landing with damaging the fuse. Second the angle of the wings when the tail is on the ground is close to stall angle, let the tail rise as your taxi speed increases before you take off. If you don't the plane will jump in the air and without enough air speed it will tip stall and crash. Good luck.
Robert

MinnFlyer

My Feedback: (4)

Good explanation Harry. Yes Bgor, towing in the wheels a few degrees will help prevent ground looping. As far as the pulling to one side, are both of your wheels turning freely? also, check to see if maybe while they are rolling, maybe one of them is being force to the inside, or outside of the Axel and rubbing on something causing it to seize up.