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Post by pnevai on Apr 5, 2005 9:53:40 GMT -7
Alrighty then. News has it that .91 engines are now going to be accepted in FAI comps. Heck why not 10 cui.
Heck why have a limit at all?
We could tether full scale Citabrias to the ground with 3/4 inch steel cable and then the pilot can sit int the thing and do the AMA pattern.
Is this move towards bigger and bigger CL stunt planes indicate that the level of skill of the pilots is slowly dropping?
Bigger airplanes mean bigger patterns and bigger patterns hide mistakes better. If your manuevers are over large then a bigger airplane will make them look smaller.
Lets look at some history here stunt was for a long time flown mainly with 35 to 45 powered airplanes. the pilots of the time were still able to routinely post 450+ point flights with smaller, lighter airplanes.
In wind or not. Many say that the little airplanes are inferior. Does that mean the top guys who flew them were light years ahead in the skill level, to be able to post those high scores?
In my oppinion we are bordering on safety issues here. A .91 engine is 30% bigger than a 60. and 60 engines are pretty large hunks of metal.
Flown the way CL is flown, should one crash and the engine be ripped from the airframe a .91 engine is a substantial hunk of metal rocketing through the air at 55 mph +. Heck a 40 size motor is scary now imagine something almost 3 times as big.
Also is it still fair letting these monsters fly in competition against the 35 to 40 size aircraft?
I am leaning to the belief that we should now create different size classes to PA competitions.
Three catagories in each displacement class
Beginner
Intermediate
Expert
In
.020 to .075
.09 to .20
.25 to .35
.40 to .46
.51 to .65
.70 +
In special situations where there are not enough competitors to fill out the individual classes. The event director could combine say the .25 to 46 classes and the .51 and above classes.
I do believe thais would give more opprotunities for people to advance and even have hopes of winning which inturn would boost participation.
My rant for the day
Peter
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Post by jehold66203 on Apr 5, 2005 11:06:09 GMT -7
I myself could care less if the guys/gals want to fly big engines. But, what are they going to do when the circle has a limit of 65' max? I am flying 40's on 65 foot lines and have no room for wandering. I am getting ready to fly the Jumbo at the casino which is a bigger site that is Fox 46 powered. Will not be able to fly it at Shawnee Mission Park. Of course the book says max line length 70 feet center of handle to center of airplane. Later, DOC Holliday
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Post by pnevai on Apr 5, 2005 12:11:05 GMT -7
Oh I don't care if guys want to fly beasts with .91 engines. I just wonder why one would feel it would be an advantage. Also fairness in competition plus the safety factor makes me wonder if it is a good thing.
I get pretty worried when I see the RC guys with some of the giant 3D planes weaving and hovering about close to the flight line. Just on freak gust of wind or interference or mistake and the recipe for disaster is right there.
In CL the plane is never more than 70ft away. And traveling at 55 or better, not just hovering on the prop. It does not take a stretch of imagination to see what could happen when a 91. sized ship smacks the ground at the bottom of a manuever.
Also is it really fair to expect identical judging of the pattern when there could be a huge difference in the size of the model doing it?
Or is everyone just going to have to start running larger and larger models because that is what the judges are used to seeing.
I can Imagine being a judge and first seeing a 700 or 800 sq plane do the pattern and the very next guy gets up flying something with 460 sq. The perception and the dyanamics are hugely different. How could one expect equal judging?
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wmiii
New arrival
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Post by wmiii on Apr 5, 2005 17:03:28 GMT -7
I'm not in favor, but it's in the rules. Question they have
to fly the beasts on 21thousant lines, right?
Walter
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Post by downunder on Apr 5, 2005 19:57:08 GMT -7
I'm having a hard time finding the justification for the bigger engines too. I just don't see the point to it. Pnevai mentioned the 700-800 size models but I'm already flying 800 (and a bit) size with only a G51 and that's got more than enough power for 59 ounces in a steady 4 stroke. The intent when I designed it was to have a very low wing loading but throw in a .91 weighing another 8 ounces or more and the wing loading goes out the window. Not only that, but it's accepted that it only takes about 1/3rd HP for level flight and (considering that I run a continuous 4 stroke with no detectable change in revs) it must still only be producing about that same 1/3rd HP through all manoeuvres.
What the proponents of the larger engines seem to be saying is that it then gives them the capability to build heavier models (not necessarily larger) and then rely on the larger prop giving more thrust when speed drops off in a corner to drag the model around by brute force rather than actually flying through the turn.
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Post by pnevai on Apr 5, 2005 21:02:13 GMT -7
Ok Bigger prop heavier airplane. But just how big a prop does one need to spin? Then with the bigger prop you get more torque effect on the airplane. So you have to compensate for this somehow. What put a lead brick on the wing tip? Else you will need to build bigger.
What prop size is ball park for a .91? 16 inches? That means you need to have over 8 inches of ground clearance. Current size planes are going to start looking pretty goofy with landing gear that long. Or are 5 blade CF props that will cost around $200 a pop be necessary.
Why on earth would you want to build a heavier airplane? Weight like drag is counter to good performance. I've built my fair share of lead sleds and found that they pretty much flew like one. Since then any stunter I've built could launch combat style. "Hold it vertical and just let go" Airplanes with nothing more than a OS35 Max S to the LA40.
Had a sig magnum with a ST51 in it that could do the same but boy the tension on that plane was a ton. Two handed flying that one was. Sadly it was lost on the highway when returning from the flying field one day.
So I never got to trim out the humongous line tension.
So I really don't get it. In this day and age with new adhesives and materials it is easier to build light than ever before. Yet the trend seems to be towards heavier and heavier stunt planes.
This makes me ask what the big fuss is over hand selected prime contest balsa stock. Or the aversion to cored foam wings or those elaborate procedures for glueing sheeting to foam wings that bleed almost every trace of adhesive away from the bonding surface.
Or are those concours finishes getting so heavy that larger motors are required.
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Post by jimthomerson on Apr 6, 2005 19:49:56 GMT -7
1/2A stunt used to be flown quite regularly in the midwest as a separate event. In the early '50's when the Fox 35, and other larger engines, started to be available to British fliers, there was a move to set up two stunt classes, one for the 2.5 diesels and another for the 35 glows. Given good flying conditions, a good 1/2A can fly an excellent pattern. 5 feet off the ground is way high  with a 1/2A on say 40 ft lines. On the other hand, the more powerful airplanes handle wind better. I think that is the advantage of the high-powered heavier airplane. Jim |
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GCB
New arrival
Posts: 22
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Post by GCB on Apr 7, 2005 6:13:10 GMT -7
Those large planes may be OK for us larger guys with dunlop, but what about small guys? Are they going to have a helper to hold them in place?
George (a .15 kind of guy)
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Post by jehold66203 on Apr 9, 2005 8:01:20 GMT -7
Where were you guys when the rule proposal was put in? I am new to the contest board so did not have a hand in the new rules. The board is supposed to vote according to the input it gets from the members of AMA. I for one do not like the over size airplanes. But, the rule has passed along with the line sizes and all other pertinent references. Now is the time to put in proposal to change or limit sizes. DOC Holliday
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Post by jimthomerson on Apr 9, 2005 9:06:58 GMT -7
I think this mirrors a change in the FAI rules over which we have some, but not complete, control. I think the general idea is to keep our rules somewhat in line with FAI rules so our fliers do not compete internationally at a disadvantage.
Jim
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Post by downunder on Apr 9, 2005 21:17:26 GMT -7
If engine size was a criteria for advantage then your AMA rules used to give an advantage over FAI in that your old max engine size was .65 compared to the .60 (10cc) limit for FAI. I don't know why the FAI decided to increase it to .91 but I'd take a bet that the AMA will adopt it as well (if they haven't already).
Come to think of it, maybe the AMA has because of the mention of increased line size. Line size (diameter, not length) isn't part of the FAI rules, only pull test. That means anyone can use a .91 with whatever line diameter they like so long as it passes the pull test.
Actually AFAIK the USA is the only country that doesn't fly to FAI rules. The AMA seems to pick and choose which FAI rules they want to use and add some of their own. Then your competitors have to make changes if they want to fly in any FAI contest.
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Post by pnevai on Apr 10, 2005 1:13:04 GMT -7
I'm not so much against the increased engine / model size, as so much as the increase has been made, perhaps it is time for subdeviding classes into displacement classes as well as pilot ability gatagories.
It is not realistic to expect a judge to be able to score aircraft that vary greatly in size back to back and come up with a good score.
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Post by jimthomerson on Apr 10, 2005 6:00:23 GMT -7
Peter, I judge and it does not seem to me to be as great a problem as you think. I've never judged a 60 piped airplane followed by a 1/2A so I've not had the complete experience.  I have judged airplanes flying on varying length lines, from @ 60 to 70 ft. Clearly the judge has to do some adjustment as to where 45 degrees is, etc. , Again, we know this and as far as I can tell do it pretty well. Maybe some one will do the trig and show us the difference in actual height for an airplane flying at 45 degrees on 60 and 60 foot lines as seen from the judges perspecitve 100 feet from the center of the circle on the upwind side. My guess is that the difference is smaller than this judge's ability to discriminate.  Jim |
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Post by 50PLUSAIRYEARS on Apr 19, 2005 16:50:15 GMT -7
Big Engines, higher HP, heavier planes? I remember a buddy of mine, 6' 3", 240 lbs, college football, built a thing for 4 Greenhead .35s. One flight, 1 month with a back brace.
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Post by pnevai on Apr 19, 2005 19:38:15 GMT -7
I'm not so much against the increased engine / model size, as so much as the increase has been made, perhaps it is time for subdeviding classes into displacement classes as well as pilot ability gatagories. It is not realistic to expect a judge to be able to score aircraft that vary greatly in size back to back and come up with a good score. I don't think that you need as big a difference as 60 vs 1/2 a. just have to see say 3 800 or more sq planes flying on 70 ft lines and then one 460 500 sq 40 sized plane like say a vector 40 flying on 62 ft lines. With the 40 things happen faster less time to view the manuever, having a far smaller airplane to track has to induce perception error. your eyes and internal rythem set to the 3 or 4 large airplanes prior, especially if they were close in flight performance would make the 40 size airplane seem very different. You can relate this phenomenon to the one after getting off of the highway after a long drive at 70 + mph. For a while 30 mph street driving feels like you are literally crawling. As the trend has been to ever bigger and heavier CLPA models I wonder if there is now a distinct disadvantage flying a 35 to 40 sized airplanes due to judging bias caused by the predominance of 60 to now 90 sized airplanes. |
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Post by ferocious on May 30, 2005 11:08:20 GMT -7
I've done a good bit of judging. The size of the plane really makes no difference to me. A good, effective judge can easily ignore the difference. But I have seen PLENTY of judges who bring a whole load of prejudices to the job who would be easily snowed by a big, impressive plane. They are easily over-awed by the big growl, fancy paint schemes, and maybe two engines, or whatever. Has happened many times at the NATS, and at countless local contests.
If you fly CLPA to WIN, you will follow the crowd.
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Post by persistant on May 30, 2005 13:12:18 GMT -7
Wasn't there an argument in the last Stunt News (maybe in Flying Models?) that smaller airplanes present better than large airplanes? Anyway, I'm having fun with a Shark 15 with TD09.
Jim Thomerson
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Post by jehold66203 on May 31, 2005 8:54:07 GMT -7
Go look at the score board. The bigger planes will be at the top of the list. DOC Holliday
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Post by jjramjett on Jun 3, 2005 7:12:42 GMT -7
I think I am insulted. After many many years of judging I thought I knew how. Now I find that I am so stupid as to not be able to differentiate between a big airplane and a small one. Why should anyone complain of a problem that has not manifested itself yet but only just might: then again it probably will not unless you just dont agree with the judges as to how good you are.
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Post by jehold66203 on Jun 3, 2005 7:57:32 GMT -7
Do not feel insulted. I have watched many flights in which I thought the pilot put in a barn burner with a profile to lose out to a built up plane. I have also seen the same with 60 size over the 35 size. It takes someone like Dave F., Ted F, Bob H. or Billy W. to really impress. DOC Holliday
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with a 1/2A on say 40 ft lines. On the other hand, the more powerful airplanes handle wind better. I think that is the advantage of the high-powered heavier airplane. 
I have judged airplanes flying on varying length lines, from @ 60 to 70 ft. Clearly the judge has to do some adjustment as to where 45 degrees is, etc. , Again, we know this and as far as I can tell do it pretty well. Maybe some one will do the trig and show us the difference in actual height for an airplane flying at 45 degrees on 60 and 60 foot lines as seen from the judges perspecitve 100 feet from the center of the circle on the upwind side. My guess is that the difference is smaller than this judge's ability to discriminate. 