Too much line tension

Ok trimming experts how does one reduce the amount of line tension without sacrificing performance in wind and overhead? I put 3 flights on my 64 ounce Legacy/Stalker.61 yesterday and it about pulled my right shoulder out of the socket. I had to take a couple of aspirins to kill the soreness so I could sleep last night.

The center of the leadouts are about 1/2 inch behind the CG, the forward leadout is almost right on the CG. It has a Rabe rudder but in level flight it is straight with the fin and just enough engine offset to make sure it wasn't pointing in. I was flying roughly 5.4 second laps on 64 foot lines.

Can I safely move the leadouts forward or should I just start lifting weights? I would guess it's pulling a good 15 to 20 pounds in level flight.

>I put 3 flights on my 64 ounce Legacy/Stalker.61
>yesterday and it about pulled my right shoulder out of the
>socket. I had to take a couple of aspirins to kill the
>soreness so I could sleep last night.
>
>The center of the leadouts are about 1/2 inch behind the CG,
>the forward leadout is almost right on the CG. I was flying roughly 5.4 second laps on 64 foot lines.
>
>Can I safely move the leadouts forward or should I just
>start lifting weights? I would guess it's pulling a good 15
>to 20 pounds in level flight.

May I introduce you to a B-17 which weighs a mere 102 ounces that flies at 5.0 seconds.

My guess here is that your lines are too short. Make sure they are 70' center to center for a plane of that power and weight.

What Bob doesn't mention is that while his Legacy is 64 ounces, Bob weighs 60 ounces soaking wet.

Bob,
I suggest a high protein, high carb, high fat, high quantity diet.

Ya Paul, I was thinking of the B-17 when I posted this, remembering a mad 3000 mile trip to Clovis just to see it fly

Thanks for the info.

>Ya Paul, I was thinking of the B-17 when I posted this,
>remembering a mad 3000 mile trip to Clovis just to see it
>fly
>

You came to Clovis that year? Maybe senility is seeping in, or the tumor is growing, but I can't recall that.

Yep, I was there. This was just after I returned to the hobby, didn't fly and was a little shy as I didn't know anybody.

>Yep, I was there. This was just after I returned to the
>hobby, didn't fly and was a little shy as I didn't know
>anybody.

Then you got rained on.

Brett

Bob,

My Intrepid weights 63.6 ounces and I fly on 65 foot lines at 5.45 laps and have no problems with too much tension. Of course when the engine leans out a little at the end the tension goes up a lot but thats after the pattern and doesn't matter.

Right, and you are not a runt. With my size and your plane I would have a problem with line tension in spite of all the lead in my @ss.

There are several possibilities:

Along with your leadout shift, you might check to see that the engine is pointing straight ahead.

However, most of the pull (I think) is probably "centrifugal" force. This pull is going as

mass*(velocity^2)/radius.

If I calculate this using your "raw" numbers (64 oz->1.8kg, 64 feet->19.5m, velocity=22.7m/s=43mph), I find that the centrifugal force that you are experiencing is "only" ~10.4 lbs (~48N)!

I may be using too short a distance (64 feet) for the radius, since that ignores your arm length, and half the wingspan. (so the force might be somewhat less). So either your estimated pull is off, or you really have a lot of yaw on this plane.

Since the mass of your plane is fixed (I assume!), you can play with line length (radius) or plane speed. So from Paul W's comment, going from 64 foot lines to 70 foot would reduce the pull by 91% (so 10 lbs->~9 lbs). I am not sure if this is actually possible since the radius actually includes your line length+1/2 the wingspan, + arm length, whereas does the 70 foot max length include the wingspan plus arm length( ??).

If you slow the plane down to lets say 5.8 second laps, the velocity would decrease by 93%, but since it enters as the square, your pull would decrease by a 87% factor (so 10 lbs ->8.7lbs.

If you do both (increase line length, and decrease velocity, you might get to 8 lbs of pull or so.

Maybe the weight training is a good idea!

I just picked up a 10 pound bolt for comparison, you are probably closer to reality than my 15 to 20 estimate, from observing the wheels it isn't yawed out a significant amount which somewhat confirms your calculations.

This is my first ever 60 powered ship and Catdaddy is somewhat correct in that I only weigh 145 lbs and am 6 foot tall, maybe I just need to get use to it.

Where is the CG on this model? If it is significantly nose heavy it will pull very hard.

My "Golden Falcon" weighed 71 oz and balanced on the leading edge at the root. It pulled like a freight train. Last October I added an additional 3 oz to the tail and reduced the pull by a third. The model weighs more but pulls less. My "Copperhead V-10" weighs 64 oz but pulls very little, it balances pretty far aft. It pulls the same everywhere though, over head and level. I am no trim expert but I do think that is what one looks for, a steady pull that provides the necessary line tension all over but no extremes like too much level and not enough on top.

With a model of this mass, I don't think any out thrust is necessary, and might contribute to some undesirable yaw in manuevers, most noticeable as you get more used to the model and try trimming it. Any of the inside/outside reversals like in the eights and especially the square eights will show this, so look critically here for yaw.

Big models pull hard, so it will take some adjustment. Practice will make it better. I'm envious of your lean condition, I'm on my way to 165 and am 5'9", currently 180. I noticed that things were pulling me around as I lost weight. I found very little weight training to go a long way.

Nice model,
Chris...

Here's a pic of Bob running in the motor on the new Legacy.

Bob,

I'm betting that in a couple months, when it is far too late to do anything about it, you will truly regret initiating this thread.

My hope is that Bill Jacklin picks up on it, featuring a reference to your girlie comments in his Stunt News column.

Hey, tell ya what. You think the Legacy pulls hard? Go fly your Flite Streak right after the PA model. You'll think it's a 1/2A-powered trainer of some sort.

So you want Bill to tell the world I'm a wimp.. Thanks allot...

just for Dan...

Dan: "My hope is that Bill Jacklin picks up on it, featuring a reference to your girlie comments in his Stunt News column."

Bob: "So you want Bill to tell the world I'm a wimp.. Thanks allot..."

No danger. I'm pretty careful about being the pot that calls the kettle black. I have in the past flown a 60-sized ship (that belonged to someone else), and I was very impressed with the line tension. It convinced me that the smaller, cheaper stuff was for me.

The Speed and Rat guys often used a little "in thrust" to kill excess line tension. Since the model is already built, I'd suspect you are stuck with what you have. Nice looking ship Bob and you're a really wirey puppy ain't ya?!

When I got married, I weighed 148 lbs. At 6'2", that was painfully thin. Right after that, my .65 speed model (37 oz) turned its best ever speed of 171 mph, not even very competitive around here. Hanging on wasn't a problem, it was the xxxx wedding ring, cutting into my finger (it seemed). I toughed it out. I think you can too, Bob. A bit of a workout will be good for you, especially 16oz curls and the fabulously effective Pizza Lift. Stop smoking. Eat some Nachos before bed, two baked potatoes with that steak. I am living proof that there is hope for you, at around 225, still 6'2". I really liked the tug of my 2Star .60 powered Lancer. Line tension isn't the problem you make it out to be. If all else fails, and you just can't deal with the outrageous pull of that flaming Legacy, send it to me. I'll pay postage. Steve

I would suggest going to 70 ft lines, center of airplane to center of handle as allowed by the rules. After that I would try adjusting your Rabe rudder to give a little "in" in level flight.

Pauls Plane pulls at 23 stones. That's alot of BEEF at the end of .018 lines.

hey bob i know what you can do just bring it to brodak and give to me i weigh 250 i like planes that pull hard lets me know there out there. it is a sharp looking plane i lkike the flames.

Bob,

Keep sneaking the LOs forward. Also check your tip weight. You may have to much in there. Keep rmoving TW until you get adverse reactions.

CG is a huge factor. The further forward the harder it pulls.

Let us know how it turns out.

Is this plane nose Heavy?

>Can I safely move the leadouts forward or should I just
>start lifting weights? I would guess it's pulling a good 15
>to 20 pounds in level flight.

I bet it's not. 20 lbs is A LOT.

If it flys like it's in trim, then the easiest way to reduce the pull is to fly slower. If I wanted to reduce the tension via trim, I would start with tip weight, not the leadouts. Most people wind up with more than necessary. When you have a lot too much, then the "wing level" test is pretty good. But to really get it right, you have to feel it in the corners. Take it out a little at a time until the airplane begins to "flow" through the corners. If you go too far, it will start getting light in the corners. By "a little", I mean something like 1/8 oz. at a time.

But, if you don't have experience with this sort of model, you might find that this is just the way they pull when they are working. To me, in heavy winds, they are near the limit for pull on both the lines and my shoulder - and I've got about 50 lbs on you!

I think you all are missing the point. Bob, while he may be rather thin, ain't a wimp. He's wiry and stronger than most. He flew my Saito-powered RC ARF-C/L project, which was 89 ounces of 5.2-lap-speed beef with no complaints. He's flow many other of my sadistic projects without a whimper. If he asks for advice on this, there is most likely an answer, and it isn't "walk it off..."
Thanks, Mitch

>I think you all are missing the point. Bob, while he may
>be rather thin, ain't a wimp. He's wiry and stronger than
>most. He flew my Saito-powered RC ARF-C/L project, which
>was 89 ounces of 5.2-lap-speed beef with no complaints.
>He's flow many other of my sadistic projects without a
>whimper. If he asks for advice on this, there is most
>likely an answer, and it isn't "walk it off..."

I didn't say it was more than he could handle - I said it was more than he might expect.

If it's pulling too hard at 5.4, fly it at 5.8.

I am going to fly it today and try to slow it down a little. It seems to be in trim, for sure not nose heavy but I am not refined enough to be able to pick up on the small trim details of wiggles and such that you guys seem to be able to.

Hoping I can go to Texarkana and get a few tips from Richard and Windy at the clinic on Friday before the contest.

Bob it is my experience in windy conditions with a 64 oz. airplane that stump pulling line tension goes with the territory! Assuming your airplane is in trim you simply brace your self and mentally be prepared. I use two hands on the handle during the level laps between maneuvers. I have also noted that early in the season the old arm is not in quite the shape it is in say August after lots of flying has been done over a period of weeks or months.

> But, if you don't have experience with this sort of
>model, you might find that this is just the way they pull
>when they are working. To me, in heavy winds, they are near
>the limit for pull on both the lines and my shoulder - and
>I've got about 50 lbs on you!
>
> Brett

>Bob it is my experience in windy conditions with a 64 oz.
>airplane that stump pulling line tension goes with the
>territory! Assuming your airplane is in trim you simply
>brace your self and mentally be prepared. I use two hands on
>the handle during the level laps between maneuvers. I have
>also noted that early in the season the old arm is not in
>quite the shape it is in say August after lots of flying has
>been done over a period of weeks or months.
>
>John Sunderland

This is one reason why some are switching to smaller, lighter models however it is not always a "Win-Win" switch. Larger models are more forgiving and can present better, while smaller lighter models tend to not pull your arm off in the wind. Smaller models require a little more attention but are much more comfortable to fly, especially in the wind.

I find I spend more time "flying" my Satona rather than just "holding on" when flying a larger model. They both work well, pick what suits your style the best.

>I find I spend more time "flying" my Satona rather than just
>"holding on" when flying a larger model. They both work
>well, pick what suits your style the best.

But I don't see a lot of movement to make them any bigger. Hence my position on the irrelevance of the ".92 two-stroke" rule.

>
>>I find I spend more time "flying" my Satona rather than just
>>"holding on" when flying a larger model. They both work
>>well, pick what suits your style the best.
>
>
> But I don't see a lot of movement to make them any
>bigger. Hence my position on the irrelevance of the ".92
>two-stroke" rule.
>
> Brett

EXACTLY! I think we could simplify it a bit and remove the whole limit rule all together. As long as the lines will pass the pull test put it up!

I had a new airplane last summer that pulled with too much line tension it turned out to be a wing warp problem. The combat airplane wt. 8.4 ounces the engine wt 6.6 oz 60 ft lines 75 mph pulled like I was holding a concret block up with the control handle. I had to fly with both hands on the control handle. I noticed the outside wing tip was flying 4" below the inside wing tip straight level flight. I twisted the wing and reheated the monocoat did a test flight twisted the wing a 2nd time and 3rd time finally got it fixed.

Today's flights we pretty uninformative except a trim issue I need to deal with. First flight was at 6.5 second laps, line tension wasn't a problem but power was, ended up flying the tank out level.

2nd flight was a little better at 6 second laps but noticed a bad tendency for the nose to come in on inside corners. Decided to disconnect the Rabe Rudder before proceeding any further, get it trimmed as best I can with a fixed rudder then make the decision on whether to hook it back up or not.

The Legacy continues.......

with us folkes getting older the joints get more tender. A little weight lifting might be in order. Nothing heavy, but try working up to 12-15lbs. for some free weight shoulder exercises. I'd been developing some shoulder pain, maybe bursitis or an old rotator cuff injury. A good set of weight exercises has gone a long way towards making flying heavy/fast planes more pleasurable and easier. Now the lines will break long before the pull gets too much.

Bob:
I'll be glad to let you have 50 lbs or so of beautiful fat.

When I first started flying my Legacy(60 oz/ST 60)I was uncomfortable with the tension but eventually got used to it. Longer lines will help for sure. I think I wound up at 67'.

Unless the wind was really up, my Legacy didn't seem to notice winds of up to 15 or so. Makes me want to come up with another 60 size airplane in a way but I want to stick with the classic designs and there are not a lot of them out there. This leads to another thread I am fixing to start.