Author Topic: The ultimate stunt machine? (Read 23449 times)

Andrew Tinsley · « **on:** February 20, 2013, 04:03:07 AM »

I have been reading back issues of the aeromodelling press from the 40s to the current times. It was fascinating to watch the evolution of the control line stunt aircraft to what we have today.
Reading some of the topics by the top flyers, it seems that power trains have been developed to such an extent that there isn't really too much of an improvement to be had.
Similarly the evolution of the modern stunter has more or less been quantified to the extent of a handful of design parameters that are now more or less standard.
Does this mean that stunt development has reached its ultimate? If so, then we are unlikely to see much significant improvement. Does this mean that when we all drop off our perches and the curtains fall on control line stunt, today's designs will be the best that are possible.
It is more than likely that aircraft designed for the current stunt schedule are indeed the best possible ........or are they? Can anyone envisage a quantum leap in design or powerplants or should the schedule be changed, in some unspecified way, to present a fresh challenge to designers?
What do people feel? Is there room for significant improvements in our favourite toys, or is this the end of the development road?

Andrew.

Peter Germann · « **Reply #1 on:** February 20, 2013, 06:49:03 AM »

Without really knowing so, I doubt that our miniature aircraft are even close to being the "ultimate" tools to manoeuvre on the surface of a hemisphere. Perhaps, if we would allow our "models" no longer looking like airplanes, a device designed for the sole purpose of travelling along the track of the FAI (or AMA) manoevres could be thought of...
Peter G.

Joseph Lijoi · « **Reply #2 on:** February 20, 2013, 07:21:28 AM »

You are living in it. Electric power will change everything. Rick Sawicki has a vectored thrust stunter out here, but I've never seen it fly The question is will there be anyone doing this in twenty years.

Brett Buck · « **Reply #3 on:** February 20, 2013, 07:59:45 AM »

Quote from: Joseph Lijoi on February 20, 2013, 07:21:28 AM

You are living in it. Electric power will change everything.

It will nudge the system on a bit, by removing that last bit of uncertainty about getting the engine to perform exactly the same way. It's not a transformation in terms of performance, but it makes it easier to get what we have struggled to get up till now.

Brett

Avaiojet · « **Reply #4 on:** February 20, 2013, 08:16:25 AM »

Quote from: Joseph Lijoi on February 20, 2013, 07:21:28 AM

You are living in it. Electric power will change everything. Rick Sawicki has a vectored thrust stunter out here, but I've never seen it fly The question is will there be anyone doing this in twenty years.

Joe,

What is a "vectored thrust stunter?"

Charles

Joseph Lijoi · « **Reply #5 on:** February 20, 2013, 11:01:18 AM »

Quote from: Avaiojet on February 20, 2013, 08:16:25 AM

Joe,

What is a "vectored thrust stunter?"

Charles

Charles

Vectored thrust is where the thrust of the engine pivots like a control surface. In jet fighters and VTO there are ducts to deflect or vector the thrust in a chosen direction. You can buy an electric motor mount that pivots for a few bucks. I'm sure it would create a ton of issues with Gyroscopic Procession and I'm sure you wouldn't want to deflect the thrust as much as an elevator but hey.....it's a concept.

I can see Bretts point of view. I guess beyond other advantages electric power will make other configurations possible, which might lead to some other changes. Not necessarily mind blowing but definte changes. Keep in mind that the peripheral technology around electric power is changing pretty fast as well. Maybe the airplanes won't change that much but the sport will. Igor Bergers indoor stunter is a definite breakthrough.

Chris Wilson · « **Reply #6 on:** February 20, 2013, 02:24:00 PM »

Quote from: Andrew Tinsley on February 20, 2013, 04:03:07 AM

Can anyone envisage a quantum leap in design or powerplants or should the schedule be changed, in some unspecified way, to present a fresh challenge to designers?
What do people feel? Is there room for significant improvements in our favourite toys, or is this the end of the development road?

Andrew.

Hi Andrew,
what I see is advancements in engine management regardless of what that engine is.
And I can't wait to see if miniaturized fuel injection, spark ignition and computer mapping etc actually makes inroads into the world of model engines. (EVO 60 sparky looks interesting!)

Just imagine how useless electric power would without its management systems and to me the real debate is how far do flyers allow their systems to do the thinking for them.

The evolution curve seems to predict that power trains will react to changing situations beyond passive presets. - so who exactly is doing the 'flying?'

We seem to be on a collision course with perfection and how boring would that be?

Cheers.

rustler · « **Reply #7 on:** February 21, 2013, 02:22:34 PM »

Quote from: Chris Wilson on February 20, 2013, 02:24:00 PM

..to me the real debate is how far do flyers allow their systems to do the thinking for them.

Exactly. Such things reduce the skill needed. As for the ultimate stunt machine - I think I'm getting there.

Tim Wescott · « **Reply #8 on:** February 21, 2013, 02:58:17 PM »

Quote from: Chris Wilson on February 20, 2013, 02:24:00 PM

The evolution curve seems to predict that power trains will react to changing situations beyond passive presets. - so who exactly is doing the 'flying?'

We seem to be on a collision course with perfection and how boring would that be?

I think that as long as you only allow a mechanical connection between pilot and control surfaces (i.e., no automatic nuthin' on the flaps or elevator, and no aileron or rudder, either), then there will always be a need for considerable pilot skill.

Who's doing the "flying" when the engine speed is regulated by a pipe? I think it's the guy holding the handle, myself.

Bill Little · « **Reply #9 on:** February 21, 2013, 03:24:16 PM »

Regardless of the powertrain, winning will come down to the person on the handle. Model design is not as "pure" as it might could be, maybe, but I do not know what else would work any better. It will still come down to talent and practice. The person doing the flying will always be the key ingredient whether it be with electric power, IC power or something else that we don't know of.

My main concern is that there will be enough new fliers to come along and keep the event alive once we have all "left the circle". I do believe the most constant members as far as contest flying are slowly aging out, although it can be done for many years. I believe the models will not change all that much, but what will the event look like in 30 years as far as numbers of competitors?

BIG Bear
RNMM/AMM

Tim Wescott · « **Reply #10 on:** February 21, 2013, 03:37:20 PM »

Quote from: Bill Little on February 21, 2013, 03:24:16 PM

My main concern is that there will be enough new fliers to come along and keep the event alive once we have all "left the circle". I do believe the most constant members as far as contest flying are slowly aging out, although it can be done for many years. I believe the models will not change all that much, but what will the event look like in 30 years as far as numbers of competitors?

I see a constant attrition due to age. But I see a constant replenishment from the other end of people who's kids are grown up enough to not be so time consuming, who are getting into (or back into) the sport after a hiatus.

I think the best things that we can do to keep the number of competitors up over the decades is twofold: one, do what we can to recruit guys from the RC fraternity, and two, give kids early experiences in control line. Even if they don't do anything with control line until they're in their 40's, giving someone an experience that'll have them saying "I'm going to do that someday" will rope them in years down the road.

Brett Buck · « **Reply #11 on:** February 21, 2013, 04:18:35 PM »

Quote from: Chris Wilson on February 20, 2013, 02:24:00 PM

The evolution curve seems to predict that power trains will react to changing situations beyond passive presets. - so who exactly is doing the 'flying?'

They have been doing that since 1949. That's what a Fox 35 does.

Brett

Chris Wilson · « **Reply #12 on:** February 21, 2013, 04:43:53 PM »

Tim and Brett,
I think that you both know what I am trying to get at here.
And despite my struggle to explain myself any better I will say that I am against 'active' systems and for 'passive' ones in the search for who actually is the pilot.

Thanks

proparc · « **Reply #13 on:** February 24, 2013, 05:45:57 PM »

Quote from: Bill Little on February 21, 2013, 03:24:16 PM

My main concern is that there will be enough new fliers to come along and keep the event alive once we have all "left the circle". I do believe the most constant members as far as contest flying are slowly aging out, although it can be done for many years.

BIG Bear
RNMM/AMM

That's the issue we should ALL be really worried about. 2 stroke, 4 stroke, pipe, electric, IMHO just doesn't make much difference because we all still fly at 55MPH, and we still do the same pattern. It's whose going to replace us when were gone-thats the issue.

phil c · « **Reply #14 on:** February 27, 2013, 01:33:55 PM »

Quote from: Andrew Tinsley on February 20, 2013, 04:03:07 AM

....Similarly the evolution of the modern stunter has more or less been quantified to the extent of a handful of design parameters that are now more or less standard.
Does this mean that stunt development has reached its ultimate? If so, then we are unlikely to see much significant improvement. .......or should the schedule be changed, in some unspecified way, to present a fresh challenge to designers?.....
Andrew.

Given that the current planes can put up a flight that the judges routinely give high scores to, and a good flyer(Chip Hyde) can impress quite a few folks after a limited amount of pattern practice, barring changes to the pattern the current equipment probably is as good as it needs to be. This does not mean that the event will die. Tennis has used basically the same equipment for a century, but it still is a challenge for even the best players. Stunt has a rather low bar to entry, as tennis does, so a prospective flyer can get just a little help and easily learn enough to start having fun. The PAMPA classes give them a good venue to practice their mistakes and they can easily graduate up the competition ladder if they choose.

Brett Buck · « **Reply #15 on:** February 27, 2013, 03:02:40 PM »

Quote from: Chris Wilson on February 21, 2013, 04:43:53 PM

Tim and Brett,
I think that you both know what I am trying to get at here.

I actually don't know what you are getting at. To me, there's not a lot of difference from a competitive standpoint between having feedback that is a function of the engine compression, nitro, prop, and having it part of an electronic feedback loop. Both can be adjusted to have the desired characteristics (if one knows what one is doing), both provide significant competition benefit, and either is commonly available to all competitors and inexpensive.

This appears to be the same sort of argument that was made when we started using tuned pipes and carbon or fiberglass props, end of the world is nigh sort of stuff. When in fact that, just like this, was a better and more reliable way of doing the things we were trying to do anyway. It made quality engine runs available to everyone, brought many more people to a competitive level, which could be interpreted as making it "easier", but we have a whole lot more people flying in the decade of the 00s than we did in the decade of the 90s.

A lot of the other stuff mentioned in this thread is either non-existent or pointless (vectored thrust? The airplanes can already corner far tighter than you can reliably control them, so why?). It's not the same sort of thing as allowing buy-and-flies that IS a fundamental change.

So, not to be argumentative, but I really don't see your point.

Brett

Howard Rush · « **Reply #16 on:** February 27, 2013, 03:52:08 PM »

Quote from: Chris Wilson on February 20, 2013, 02:24:00 PM

The evolution curve seems to predict that power trains will react to changing situations beyond passive presets.

As do the autothrottles of the first three places at the last F2B world champs.

Chris Wilson · « **Reply #17 on:** February 27, 2013, 05:10:57 PM »

Quote from: Brett Buck on February 27, 2013, 03:02:40 PM

I actually don't know what you are getting at.

I was running under the assumption that you may have remembered my point of view from previous replies on this forum also - I have been consistent about my views on this, as have you. If I remember correctly I used the parallel of electric drag cars in the States being banned for being too effective.

Quote from: Brett Buck on February 27, 2013, 03:02:40 PM

To me, there's not a lot of difference from a competitive standpoint between having feedback that is a function of the engine compression, nitro, prop, and having it part of an electronic feedback loop. Both can be adjusted to have the desired characteristics (if one knows what one is doing), both provide significant competition benefit, and either is commonly available to all competitors and inexpensive.

The difference between resonant and chemical management systems(and that is the point here, not a hybrid of the two) as opposed to electrical ones is that the first is virtually at an evolutionary standstill and the other on the rise.
One is totally stuck in the realm of pilot presets and reacts passively according to those presets, and the other has the potential to dynamically make up its mind on the fly according to presets determined by what ever software designer deemed plausible to write. So who is making the inflight decisions with an active system?

Quote from: Brett Buck on February 27, 2013, 03:02:40 PM

This appears to be the same sort of argument that was made when we started using tuned pipes and carbon or fiberglass props, end of the world is nigh sort of stuff. When in fact that, just like this, was a better and more reliable way of doing the things we were trying to do anyway. It made quality engine runs available to everyone, brought many more people to a competitive level, which could be interpreted as making it "easier", but we have a whole lot more people flying in the decade of the 00s than we did in the decade of the 90s.

Again, I am not against resonant and chemical systems in any way so why say that 'this' sort of argument is end of the world stuff?
But I am against the elimination of human error and its deduction from perfection - and is that not how the pattern is scored anyway?

Quote from: Brett Buck on February 27, 2013, 03:02:40 PM

So, not to be argumentative, but I really don't see your point.
Brett

Hopefully I have been lucid enough this time around for you to see my point and ultimately, my opinion.

Thanks.

(F2B, got an app for that - urrgh!)

Trostle · « **Reply #18 on:** February 27, 2013, 05:50:38 PM »

Quote from: Andrew Tinsley on February 20, 2013, 04:03:07 AM

(Clip)

Can anyone envisage a quantum leap in design or powerplants or should the schedule be changed, in some unspecified way, to present a fresh challenge to designers?
(Clip)

Andrew.

Almost on a regular six to twelve month schedule, the idea comes up to change "the schedule". This time, it is an open suggestion to change the pattern "in some unspecified way". Interesting idea but some thought needs to be given to it.

First, let's remember that the pattern was recently changed to eliminate the specified turn radius of the corners in those maneuvers that required a 5-foot minimum turn radius. These corners are now all specified "to be of a tight radius". In my own humble opinion, I think this was a change for the good of the event. No CLPA stunt ship is capable of even coming close to the proverbial 5-foot corners unless the stunt world is ready to accept the freakish design excursions like Rich Porter's "Ridiculous" in 1985 (aptly named) and some other ideas from him. Time has shown that the CLPA community is not ready to accept that design approach as a norm for our event. However, tight corners are still important. With proper judging, two flights which are similar regarding size, overall shape, intersections, and bottoms, the pattern with the tighter corners will still get a higher score because not only are the corners tighter, the shapes of those maneuvers with tighter corners will be closer to the rulebook criteria. And my experience as a judge over the past several years, I think it is easier to judge and assign a score with the new "of a tight radius" requirement.

Next, consider what makes up our pattern. It is a series of inside and outside loops in various combinations and locations, plus various square inside and outside loops with something resembling right angle turns in various combinations and locations, and a couple of maneuvers that require something that resemble (but actually less than) 120^o turns.

So, what could be added to our pattern that in one form or another is not already incorporated in our pattern? Yes, for example, we could maybe use "outside triangles", but they are still triangles requiring no new technology to perform well. And yes, we could put together any number of imaginative maneuvers (and I can provide a list of dozens) including the ideas used many years ago in the New York Mirror meets (and recently resurrected by the Tulsa Glue Dobbers if not others), but all of those are still various combinations of loops and "tight" corners. The only thing that would really start to push the performance envelope of our CLPA models would be to make these maneuvers that consist of combinations of loops and "tight" corners all smaller. Instead of the specifications for the current maneuvers where most are defined to be performed within 45^o and 90^o parameters, put that series of loops and tight corners within 30^o and 60^o parameters. That would be a real challenge for most designs and pilots today where a true 45^o/90^o pattern is seldom seen except at the highest level of competition and when good judges are used.

What I am saying is if there is to be a "fresh challenge to designers" as well as a "fresh challenge" to pilots, the first step would be to have a universal understanding of how a true 45^o/90^o pattern is to be flown and judged.

We have had this set of AMA maneuvers for over 50 years. Has there been improvements in our equipment over that time? The answer is a resounding YES!, albeit rather slow. Much of this evolutionary process can be mapped with the improvements in readily available power plants and how to operate them. We have materials and construction techniques available now not even dreamed of 50 years ago. The trial and error process over that 60 years has pretty much evolved to a set of design parameters that work better than designs that venture beyond that sphere of influence (the Ridiculous notwithstanding). Knowledge of how to trim these models has also been a significant influence on how well our models can be flown, (though again in my humble opinion, there are only a handfull of true golden arms that can quickly and accurately diagnose and correct trim problems, though those procedures are known and published for all to learn.)

Unless I am missing something here, I do not see that there would be much interest or need to seriously change our pattern unless we truly want to require our models to perform maneuvers much smaller than what is now required. But before we do that, I would suggest (in my humble opinion) that more emphasis should be given to fly our maneuvers to the current requirements.

Keith

Brett Buck · « **Reply #19 on:** February 27, 2013, 06:19:48 PM »

Quote from: Trostle on February 27, 2013, 05:50:38 PM

First, let's remember that the pattern was recently changed to eliminate the specified turn radius of the corners in those maneuvers that required a 5-foot minimum turn radius. These corners are now all specified "to be of a tight radius". In my own humble opinion, I think this was a change for the good of the event. No CLPA stunt ship is capable of even coming close to the proverbial 5-foot corners unless the stunt world is ready to accept the freakish design excursions like Rich Porter's "Ridiculous" in 1985 (aptly named) and some other ideas from him. Time has shown that the CLPA community is not ready to accept that design approach as a norm for our event. However, tight corners are still important. With proper judging, two flights which are similar regarding size, overall shape, intersections, and bottoms, the pattern with the tighter corners will still get a higher score because not only are the corners tighter, the shapes of those maneuvers with tighter corners will be closer to the rulebook criteria. And my experience as a judge over the past several years, I think it is easier to judge and assign a score with the new "of a tight radius" requirement.

Thank you!

The idea, of course, was to merely change it so that it matched up with what a judge was going to do anyway. No one is sitting out there with a measuring device to determine the radius. What happens with top-rank judges in big contests with top competitors is that those that make the least number of mistakes win, and a tight-appearing corner is less of a mistake than a soft-appearing corner. Boils down to, in the best competition, the appearance of tighter corner radii is typically a huge factor in who wins the contest. That's what was happening anyway, it didn't matter if I had changed it to "tight" corner or changed the specified radius to 0.

Changing it to something else, like 20 feet (which can be done, although it usually isn't) makes it *harder* to judge because you still can't measure it on the fly during a flight and now you have 7 people all with a different idea of what constitutes "soft", "just right", and "too tight" (since that would also be a possibility).

The other reason was psychological and the reasoning is exhibited in this thread (and lots of others). 5 feet looks like an engineering requirement and a HUGE number of people, myself included for a while, homed in on this to the exclusion of the other 5000 or so words also used to describe the event. This resulted in people going off on tangents trying to do 5 foot corners without regard for everything else, and then not understanding why their results were not as expected. Swell, you did 9 foot corners but couldn't fly the airplane level, your mistakes in the rest of the maneuver far outweighed the reduction in the turn radius. This also led to many of the same people and other straphangers going on endlessly about how "stunt is fraud and everybody ignores the rules", when in fact, the "5 feet" people were only looking at one of the rules and ignoring the others, then whining about it afterwards. Can't do that now.

Aldrich knew that 5 feet wasn't right within weeks of putting it in the rule book. They just never bothered to go back and change it.

Brett

Chris Wilson · « **Reply #20 on:** February 27, 2013, 07:07:40 PM »

One opinion.

Brett Buck · « **Reply #21 on:** February 27, 2013, 07:32:28 PM »

Quote from: Chris Wilson on February 27, 2013, 07:07:40 PM

One opinion.

. That was Rich Porter in the "Ridiculous" construction article. His airplane turned corners that were measured to be somewhat tighter than normal (something around 7 feet vice 13), appeared only a little tighter than normal (a combination of the "windup" being nothing exceptional, and the short lines which made the corner dimensions a larger fraction of the maneuver sides), but didn't repeatedly hit 90 degree corners, 120 degree corners, fly in straight lines reliably, and did not track well in rounds. That, and some other errors that were similar to what everybody else does, was why the results did not come out the way he wanted them to.

I told him that in person, did not register, and he showed up with his "stunt ball" around his neck like a necklace the next morning at the pilots meeting. Paul Walker's airplane appeared to turn *much* tighter than Rich's (due to much longer lines, no appearance of "windup" at all), whether it did or not, and Paul's corner angles, resultant shapes, and straight lines were *vastly* superior. Paul won the contest, Rich was properly placed at about 10th. This was at one of the Northwest Regionals, maybe 1994.

I had no real issues with Rich and he's amiable enough in person but he is the prototypical example of what I was talking about.

Brett

Igor Burger · « **Reply #22 on:** March 01, 2013, 02:39:34 AM »

Those active timers we use are simulatig 4-2-4 switch of IC engines (well little improved simulation

). It is almost identical, so I do not see any "thinking instead of pilot". The "nose up" power gain is natural to IC engines, so why not to have it on electric? The only difference is, that proper setting is not black magic of playing with prop, venturi, pipe nitro etc, it is simply numeric parameter, means it allows people simply set and forget type of use. I know that some people do not like it, because it cuts the knowledge advantage gained passed 50 years of using IC engines but that is the life ...

Air Ministry . · « **Reply #23 on:** March 01, 2013, 06:37:54 PM »

We could have a Electronic Pilot next .

So the ' Aeromodeler ' could sit there and enjoy a few beers , while the model flys itself .

phil c · « **Reply #24 on:** March 03, 2013, 09:16:30 PM »

With the current pattern, from what I've seen, is that flyers of similar skill levels all make all sorts of mistakes of greater or lesser degree on every flight. On normal days that prevails in all the events and the scores tend to be very close, or perhaps in 2-3 separate but close bunches.

On a few really good days, or perhaps a few flyers who are right on, put in flights where they make 2 or 3 maneuvers that are noticeably better than the average. Good judges will notice that immediately and give them scores that stand out also. It is very hard to pick up 10 pts by convincing the judges your flight was 1 pt better on some maneuvers and 1 pt less bad on a few others. Everybody is making one point mistakes all over the place. Show them 2 or 3 manuevers that standout and good judges will gladly hand out an extra 10 pts.

One thing about electric that I haven't seen anyone comment on is the lack of a smoke trail. Most engine powered stunters leave a pretty thick smoke trail. This can give the judges either a very hard to ignore reference for something like tracking in loops, or a very serious optical illusion where the flaps kick the smoke trail in a sharp corner and make the it look like the plane bobbles, even though it sails smoothly through.

I've got one video showing a reverse wingover. I happend to watch the flight in person and the smoke trail made it appear very clearly that the plane overshot the turn and then corrected back to a straight path. Later, looking at the video, it was clear that the plane actually did a somewhat soft third turn where the fuselage overturned, the smoke trail kicked out, and then fuselage straightened out, but the path of the plane was a smooth, sharp turn with no overshoot or bobble of any kind.

Maybe we need some special glasses for the judges to fuzz up the center if their field of view a bit so they are less distracted by what is going on around the model and can keep focussed on the big picture.

Trostle · « **Reply #25 on:** March 04, 2013, 12:30:58 AM »

Quote from: phil c on March 03, 2013, 09:16:30 PM

One thing about electric that I haven't seen anyone comment on is the lack of a smoke trail. Most engine powered stunters leave a pretty thick smoke trail. This can give the judges either a very hard to ignore reference ...

Phil,

You brought up a subject here that is not often discussed and it should be. At judges' clinics I have conducted, I have been asked about using the exhaust trail to help judge/score how well any particular maneuver is flown. My recommendation is to try to ignore the exhaust trail as much as possible. One of the reasons to ignore that exhaust trail is as you have described. Another is that the wind will affect that exhaust trail in different ways depending on the position of the different maneuvers relative to the wind. Another reason is that depending on the models/engines involved and the atmospherics at any given time, there will be times where the exhaust trail will vary from very noticeable to barely perceptible, and now with the electrics, non existant. So, under all of these conditions, there is absolutely no consistent appearance of the exhaust trail to give a consistent basis to compare and score a maneuver.

Keith

Dennis Moritz · « **Reply #26 on:** March 07, 2013, 11:34:59 PM »

People of ability and inspiration can arrive on the scene and push through a break through. Never know when. Electric for instance. Adopted successfully for stunt a few years back. Even after a second at the NATs in Advanced, more naysayers than advocates. Now considered a revolution by many if not most. The "modern" stunt pattern dates from 1953. Sixty years and counting. Given the time line, the approaches to design were configured by a comparatively few individuals. A number of whom have spanned most of the currently in vogue approaches. Perhaps active technology, like that used in RC Helicopters, will work here. Or something else. I know some of us think of stunt as an constantly innovative sport. Doesn't look like that to me. More like tennis. Tennis still uses a racket that looks something like the original racket. I like our rituals and slowly progressing technologies. Always feels like I'm getting deeper into this. But. Who knows. Someone new may show up and turn our traditions on edge. Or an old dog might in a moment of original thinking, think up a new trick.

Howard Rush · « **Reply #27 on:** March 08, 2013, 12:45:01 AM »

Quote from: Dennis Moritz on March 07, 2013, 11:34:59 PM

P

Sure, that could indicate a low pullout, but, as with smoke, just watch the airplane's track as Keith says.

Dennis Moritz · « **Reply #28 on:** March 08, 2013, 07:31:26 AM »

My iphone deleted my previous post, only left a P. Howard intuited most of the paragraph. However, for the rest, I wrote something out that might be analogous to what I was thinking last night. The muddle feels similar. Yes. I did try to @#$% some people off. I remember that. But the jabs are very mild and carefully cloaked. Easily overlooked.

phil c · « **Reply #29 on:** March 10, 2013, 10:17:26 PM »

Quote from: Brett Buck on February 27, 2013, 07:32:28 PM

.........(Rich Porter) His airplane turned corners that were measured to be somewhat tighter than normal (something around 7 feet vice 13), appeared only a little tighter than normal (a combination of the "windup" being nothing exceptional, and the short lines which made the corner dimensions a larger fraction of the maneuver sides), but didn't .......

Brett

An interesting observation Brett. I did a little figureing awhile back. It appeared to me that a Rich style plane, with a highly tapered wing, ala' the Firecracker, gobs of power, 1000sq.in. weighing about 45 oz.(flapless) or 55 oz(flapped) and probably a lot of outthrust to keep it out on 70 ft. lines could make some very significant inroads in a "corner of tight radius". It would probably take several design interations to work out the balance point/tail volume/flaps ratios to make it stable. It would also have to fly at about 45 mph. Much faster and the corner is too fast for the pilot to react to.

From what I saw of Rich's planes he definitely got a tight corner, but sacrificed everything else, including precision to do it.

steven yampolsky · « **Reply #30 on:** March 11, 2013, 12:08:23 PM »

Quote from: Joseph Lijoi on February 20, 2013, 07:21:28 AM

You are living in it. Electric power will change everything.

Hmm. 2011 WC winning model was powered by a 40 year old motor that is no longer in production. No pipes or no electrics. 2009 WC model had a .75 on a pipe. Electrics is an evolution, not a revolution. Although....................

EVERYTONE LISTEN TO ME! Electrics is the future! IC motors are destined to become paper weights! Sell your IC motors now before they become worthless!!! I will buy all your RoJett, PA and AeroTiger motors for a fair and honest price of $50 per motor as long as they are in good working order! There is no limit on how many motors you can sell! Hurry before your PA 75 becomes worthless hunk of metal!

Brett Buck · « **Reply #31 on:** March 12, 2013, 10:34:36 PM »

Quote from: Steven Yampolsky on March 11, 2013, 12:08:23 PM

EVERYTONE LISTEN TO ME! Electrics is the future! IC motors are destined to become paper weights! Sell your IC motors now before they become worthless!!! I will buy all your RoJett, PA and AeroTiger motors for a fair and honest price of $50 per motor as long as they are in good working order! There is no limit on how many motors you can sell! Hurry before your PA 75 becomes worthless hunk of metal!

See, now there's a guy who is just looking out for our collective best interest. Selflessly willing to take a huge personal loss just to help everyone else ditch their old junk. Kudos, sir, kudos!

Brett

FLOYD CARTER · « **Reply #32 on:** March 20, 2013, 11:19:40 AM »

No matter how well you fly, the judges must be even better flyers! Otherwise, they will miss your small mistakes, giving you a bogus score (larger or smaller).

Selection of really qualified and experienced judges is a crucial choice that the average CD often ignores, or else gives insufficient weight to.

If you hold a contest using just anybody who will volunteer for judging, the end result is that most contestants will feel that their scores have little relationship to their actual flight performance.

Brett Buck · « **Reply #33 on:** March 20, 2013, 12:23:22 PM »

Quote from: FLOYD CARTER on March 20, 2013, 11:19:40 AM

No matter how well you fly, the judges must be even better flyers! Otherwise, they will miss your small mistakes, giving you a bogus score (larger or smaller).

Selection of really qualified and experienced judges is a crucial choice that the average CD often ignores, or else gives insufficient weight to.

Absolutely. We have done very well at the larger contests over the years but competent judges are a critical resource. The one thing guaranteed to get most top competitors blood boiling is people complaining about it. You take a NATs or TT, the pilots generally never have a significant complaint about it any more, and when you do hear it, it's an instant argument/fight. Most of the infighting people have seen over the years in PAMPA, for example, was ultimately over the topic of judges getting attacked for their scores. I am personally amazed at how well the various errors are picked up and weighted, and how consistent it all is. Then consider that the judges volunteer for these contests, and spend their entire vacations in some cases standing out on the hot blacktop so the rest of us can whine about having to fly for 16 minutes a day and generally act (mostly politely) like prima donnas.

Brett

Bill Little · « **Reply #34 on:** March 20, 2013, 12:40:56 PM »

Hi Brett,

I remember the last NATS that I actually flew at. The Judges I had were brutally honest (which I appreciated!) and got the scores on our circle right. I don't really care about the number of points I get, just whether or not the judges get the order of best to last correctly. I felt that at that time, the job was done correctly.

BIG Bear
RNMM/AMM

Andrew Tinsley · « **Reply #35 on:** May 07, 2013, 07:53:14 AM »

Thanks for all the input. Amazing how off topic people can get! Apologies to you Keith, the "add in bit" about maybe change the schedule was probably designed to ignite your ire. That was off topic. What I was really looking at was the evolution of the stunt aeroplane. Power train is somewhat academic, as IC and electric probably have little to choose between them, despite the entrenched opposite camps!
It seems that most people think that there isn't really much further to go in terms of evolution. If control line is still being flown in 50 years time, it would be interesting to come back and see if this conclusion was correct. I suspect it will be so, simply because no one will be left to do any more development!

Thanks everyone

Joseph Lijoi · « **Reply #36 on:** May 07, 2013, 03:29:14 PM »

Quote from: Andrew Tinsley on May 07, 2013, 07:53:14 AM

Power train is somewhat academic, as IC and electric probably have little to choose between them, despite the entrenched opposite camps!

I guess you must be talking whip control. Bill Werwage once said in (the Juno article) that the power train was 3/4 of a stunt ship.

Your question is academic. You are not asking what is the largest stunt machine, or what is the fastest stunt machine, you are asking what is the "ultimate" stunt machine.

The obvious answer is that the ultimate stunt machine is the one that wins.

Brett Buck · « **Reply #37 on:** May 07, 2013, 07:22:59 PM »

Quote from: Andrew Tinsley on May 07, 2013, 07:53:14 AM

. What I was really looking at was the evolution of the stunt aeroplane. Power train is somewhat academic, as IC and electric probably have little to choose between them, despite the entrenched opposite camps!

I see far less sectarian activity on Electric VS IC among the competitors than most other "revolutions". Certainly nothing like "ST60 vs Tuned Pipe", which was clearly the worst example, not even like the mild divisions over "Tuned Pipe VS 4-stroke". The big difference is that it's obviously an improvement in reliability, but it's not a huge leap in performance like Tuned Pipes were in 1988. Then, you pretty much had to do it to be competitive. 4-strokes and Electric are decent working alternatives but not mandatory.

I predict that Electric will not raise the peak performance or score capability consequentially, and TP and "modern ST60" like the Retro will still be perfectly competitive at the highest levels. But, just like Tuned Pipe and semi-custom engines, it will raise the average flight tremendously, and make many more people competitive than were before. Because the propulsion has always been a deciding factor, and now literally anyone can reproduce a perfect run at any time.

We have gone from a complete crap-shoot as far as engines go (ringed and semi-slag 4-2 break motors) to what amounts to a no-brainer (TP, 4-stroke and now Electric) in the space of less than 30 years. ANYONE can get any run they want with very little effort and arbitrary amounts of power at any time.

This is not a problem, it's a fantastic advance that we should all be very happy about!

Brett

Andrew Tinsley · « **Reply #38 on:** May 08, 2013, 05:18:07 AM »

Hi Joseph.
I am not sure your point is correct. This started with me reading past Aeromodeller Annuals and watching the evolution of stunt ships over the past 65 years or so. After that long period of development we now seem to have some standard numbers around which "new" designs are drawn up. The rate of change of innovation is slowing right down. This is what got me wondering if we had reached a final design approach for stunt models. I couldn't really see any direction in which the design aspect of our planes could go, hence the question.
I muddied the waters a little by asking about a change of schedule. Big mistake and apologies to Keith. Motive power development seems to have reached a plateau whichever form you prefer, so the question was not intended to drag in power trains. Just design of planes was the object of the question.
If "the last plane that won a contest" is the answer that satisfies you, then fine. It certainly doesn't satisfy me! Design evolution is NOT academic, it is something that is real and affects us all. The difference between a top F2b design of today and a Jim Walker Firebaby (hope this is correct as I am not a US modeller!) is hardly academic.
All I intended by the question was to see if anyone could see an approach that would improve the performance of the airframe. Hope that clarifies my thinking.

Regards,

Andrew

Air Ministry . · « **Reply #39 on:** May 09, 2013, 01:14:58 AM »

MORE Modified Noblerts with flash paint jobs .

Arrgghh .

In ' design ' once you set a few parameters , the rest start to dictate themselves .

Typical of this is ' Light Engines ' . if someone uses on that isnt light , the formular starts shifting .

anyone used a old O.S. max 80 for F2B .

Howard Rush · « **Reply #40 on:** May 09, 2013, 09:04:17 AM »

Quote from: Andrew Tinsley on May 08, 2013, 05:18:07 AM

The rate of change of innovation is slowing right down. This is what got me wondering if we had reached a final design approach for stunt models. I couldn't really see any direction in which the design aspect of our planes could go, hence the question.

My impression is the opposite. Read Igor's article in Stunt News. MEMS sensors are enabling sophisticated autothrottles-- even autopilots unless we keep electronics out of the pitch axis. Now we're messing with the boundary layer on the wing and tail.

Brett Buck · « **Reply #41 on:** May 09, 2013, 09:30:14 AM »

Quote from: Howard Rush on May 09, 2013, 09:04:17 AM

My impression is the opposite. Read Igor's article in Stunt News. MEMS sensors are enabling sophisticated autothrottles-- even autopilots unless we keep electronics out of the pitch axis. Now we're messing with the boundary layer on the wing and tail.

The factor you are missing is that most everyone *doesn't actually realize what Igor is doing* or how incredibly sophisticated it is (and could be). Unless we start sprouting canards or triplane tails, it might as well be Green Box Noblers/

Brett

Andrew Tinsley · « **Reply #42 on:** May 09, 2013, 11:17:27 AM »

I am afraid being an overseas member of the forum, I don't get to read Stunt News. I have only the slightest knowledge of Igor's activity, but autothrottles are really a power train issue. Boundary layer stuff sounds interesting and doubtless I will catch up with that work! So is it really Green Box Noblers that still reign supreme!?

Andrew.

Jim Thomerson · « **Reply #43 on:** May 09, 2013, 01:42:12 PM »

The original Nobler was designed to fly the OTS pattern. That it is still competitive at a high level with the right person on the handle (and perhaps the right engine) suggests that the two factors of flier and power are, in fact, the principle components of a successful stunt airplane.

I judged Classic at the VSC last year. I was amazed at the quality of the patterns I saw flown with classic era airplanes.

Trostle · « **Reply #44 on:** May 09, 2013, 03:00:25 PM »

Quote from: Matt Spencer on May 09, 2013, 01:14:58 AM

MORE Modified Noblerts with flash paint jobs . Arrgghh .

In ' design ' once you set a few parameters , the rest start to dictate themselves .

Typical of this is ' Light Engines ' . if someone uses on that isnt light , the formular starts shifting .

anyone used a old O.S. max 80 for F2B .

Matt,

At the time that OS 80H was in vogue, primarily for RC scale, the displacement limit for F2B was 10cc. That OS 80 is about 13.1cc.

The OS 60H appeared in the early-mid 70's and was also used for RC scale. The OS 80 came out a few years after their 60H. But that was at the time when, at least in the U.S., the ST 46 was being used extensively and the ST 60 had not yet been "discovered" by the CL stunt community. So, these OS H engines did not really get any atention at least here in the U.S. by the CL people. Those OS H engines were not known for overwheming power compared to the later schnuerle engines, but they could carry heavy scale airplanes and were dependable.

Keith

Lauri Malila · « **Reply #45 on:** May 09, 2013, 05:03:15 PM »

Hi.

Yep, even when electrics are going to dominate, there is still stupid ones who choose to waste their time with old technology. The problem in IC development (and so many other things in stunt) is that very few really has balls to do serious, fearless development work. To go to unknown. There is so many fixations about what works and what doesn't, mostly based on findings from old or otherwise not perfected stuff. Metallurgy is one thing, and another thing is general understanding of basic thermodynamic principles in 2-stroke engines.
I don't really undestand the fame of so many modern stunt engines, I mean the PA's, Jett's ad such. Sure, they usually run well, but to me (but I can be wrong) they are just mildly timed Schnuerles. They have so much potential, especially now when the rules allow the big displacement. Well, allready for quite a few years but anyway.
I feel that the development has stopped in halfway. I still dont understand the equation: shitloads of power and lots of noise. Today people should be more interested in reducing the noise, actually that should be the main objective in the development of them big engines. And less noise does not mean a too restrictive exhaust system. Reactivity is a stupid way, absorption is better. With some knowledge of acoustics, it is possible to build an efficient silencer that is about neutral to the engine. Usually one ends up with a silencer that has too LITTLE resistance. It's a good starting point, though.
Also, I'm quite convinced now that piston ring technology is the ideal way to go. But it has a bad reputation because of so many bad experiences with Engines that have a questionnable metallurgy and design. If the ring gets stuck in an ST, it doesn't mean that the whole idea is crap. (But it seems that a classical stunt engine needs to be crap, many horrible things working together in harmony. I mean bad burning efficiency, inefficient scavenging, bad thermal flow etc.) The price you have to pay is an occasional need of cleaning, not a big deal if you know what you are doing, but enough to ruin the reputation of one approach.
Like this for example, our 12,6cc (.77) engine: weight of engine is 9,5oz, plus muffler which is about 1,5oz. It turns an 14,2x5,5" 3-blade prop at about 6800rpm. I just came from flying, the engine was still a bit on rich side but fuel consumption in pouring rain weather was only 3,4oz/6 1/2 minute flight. And I know that the run gets even better in higher temperature. Power is absolutely not an issue, and hey, no nitro!
Also, I use quite a lot of castor oil, 10% in total of 20% oil mix. After about 800 flights there is no sign of burn residue inside the engine, thanks to Robbie's out-of-box thinking, piston scavenging and monolithic construction. And of course the top-notch tribology.
But it's lots and lots of work, most people don't understand it when everything must be available as ready-to-go. I go out just a few times for some unsuccesfull experiments and to eyewitnesses that don't know much the project is doomed to fail.

Sorry. L

Keith Renecle · « **Reply #46 on:** May 10, 2013, 01:57:14 AM »

Hi Lauri,

Thanks for posting such a good opinion.....as always! What a clever chap Rob Metkemeijer is as well. I got to fly his Shark with one of his prototype engines a few years ago when Rob flew at our Nats here in Darkest Africa. If I remember correctly it only used about 3 oz of low nitro fuel at our altitude of 5000 ft. The power and control was fantastic with the 3-bladed 14" prop, and so quiet as well. I saw your Shark fly in Bulgaria and it looked very good, so I would agree with you about the fact that a lot more can still be done on engine development...... IF people like Rob get support. Yuri Yatsenko is another good example of someone putting years of development into stunt engines.

On the issue of Andrew's question, the development since the Nobler has been significant, but this was not due, in my opinion, to radically different aircraft design changes, but mainly as others have said, due to the materials that are readily available. Even just the control systems, as simple and basic as they are, have been improved a lot through the years, and combined with good reliable power plants, have certainly allowed many more pilots to fly a lot better than just the few top experts. I did get to fly Igor's winning model in Bulgaria, and having been most impressed by the Yatsenko Shark with Rob's engine before, I have to say that Igor's Max Bee was a little easier to fly and more tolerant of my "not-so-great" flying ability. Igor's Max design and now the Max Bee have a few really good design innovations that allow this, so although these may appear to be minute points, there have been some good innovative design changes in recent times that do certainly make that minute difference between the top 10 fliers in the world champs.

Keith R

t michael jennings · « **Reply #47 on:** May 13, 2013, 08:38:34 AM »

Gentlemen,

Maybe a good place to look for potential Control Line aircraft design improvements would be the new model aircraft flying technologies.

For instance, check the cover of the current Model Aviation (April 2013).
See the attached scan.

Note the following design measurements of the ParkZone VisionAir aircraft on the cover of Model Aviation.
My measurements may not be exact, but they are reasonable accurate.

1) at wing root; the flap is 32% of the wing cord,
2) at wing tip; the flap is 26% of the wing cord,
3) the wing taper ratio is 68%,
4) the stabilizer area is 34% while the elevator area is 66%,
5) the taper ratio of the stabilizer/elevator is approximate 50%.

Question: Why would a Control Line designer consider a Park Zone aircraft?
Answer: The Park Zone aircraft are similar to the Ultra Light aircraft or full size aircraft. They address the basics of flying technologies.

Is there a designer out there that would design a Control Line model with similar measurements?

These comments are my opinions.
Feel free to disagree.

T Michael Jennings

Knoxville, TN

Howard Rush · « **Reply #48 on:** May 13, 2013, 12:32:09 PM »

In summary, RC planes have electric servos to react the hinge moment. CL airplanes have line length difference at the end of long springs.

Dave_Trible · « **Reply #49 on:** May 27, 2013, 07:35:38 PM »

Quote from: Ty Marcucci on May 27, 2013, 04:35:58 PM

The question, "What is the ultimate stunt machine?" does not seem to have been answered. I think the answer would be the machine that won the last Nats and or World Champs. Ultimate machines always get better along with the pilot. There is NO ultimate, just some that were or are for the moment.

Its a lot like asking who the most beautiful woman is... Everyone has there own tastes and ideas. What turns one on is a dud to another. Then, as Ty said 'some that were or are for the moment'.

Dave

Howard Rush · « **Reply #50 on:** May 28, 2013, 02:38:23 PM »

Quote from: Dave_Trible on May 27, 2013, 07:35:38 PM

Its a lot like asking who the most beautiful woman is.

Except in stunt you won't get in trouble posting the scores.

david w bahm · « **Reply #51 on:** July 09, 2013, 09:06:15 AM »

I am no stunt expert by any means and if I flew in competition you'd have to tunnel to find out where I finished when the scores were tallied. But in spite of all that I will say in being obsessed with the 5 ft radius corner the rest of my pattern (what I can fly of it) suffers accordingly. Every airplane I set up to try to fly the corner to the letter of the rule book wound up being too much to handle as to control input. I had one ship which would practically pivot on the end of the lines but once the turn was established it was to quick to stop. This resulted in many powered inverted landings and much subsequent damage. The model would also not track reliably in level flight and I was constantly "getting behind the airplane" in normal flight regime. Made for some pretty wild rides. While alot of it was attributed to both a far aft CG (in order to achieve the rule book 5 ft radius) and my less than expert flying skills, once the CG was brought back to a range within bounds to where it could be controlled, the turn radius did open but a much more definitive and consistent pattern was achieved. I think Keith's point is right on the money as the term tight allows a little leeway for the pilot to establish a flow to his/her pattern that lends itself to the flight parameters of the equipment resulting in a more consistent pattern that flows together. Kinda like a figure skating routine if you will.

Brett Buck · « **Reply #52 on:** July 09, 2013, 05:14:37 PM »

Quote from: Ty Marcucci on July 09, 2013, 10:24:31 AM

From what I have gathered, Shapes, Intersections and Size of the maneuver is more important than a very sharp unobtainable corner.

They are more-or-less equally important. The problem has always been that people would home in on one aspect (like the corners) and disregard the others.

Brett

Bill Little · « **Reply #53 on:** July 13, 2013, 05:26:23 PM »

In the past, when I was flying the Spacehound, I was told it presented very well in the pattern. This model has an uber tiny tail and as such does not have a really good "square" corner. It does do excellent rounds, though! By using a good ST.46 in an otherwise .35-.40 size plane did help in keeping the model flying when I tried to bang a corner. Compared to a T-Bird II that I had about the same time which seemed to just rotate 90* and change direction. The T-Bird II does have a much thicker airfoil, but otherwise about the same wing area, etc.. Wish I knew a lot more about why these planes do the things they do, but I will just go on by stealing the designs from the top guys!

BIG Bear
RNMM/AMM

Jim Carter · « **Reply #54 on:** July 13, 2013, 07:32:39 PM »

Quote from: Matt Spencer on May 09, 2013, 01:14:58 AM

".... anyone used a old O.S. max 80 for F2B .

Wow! That would be kool on my Ringmaster!! How soon can I borrow it?? Think I'll need a muffler??

Andrew Tinsley · « **Reply #55 on:** July 18, 2013, 08:50:37 AM »

Hello Ty,
With respect, the question was NOT "what is the ultimate stunt machine". I was watching the development of control line stunt from the late 1940s to the present. My question was really intended to see where people thought that stunt design was heading for. There will be an ultimate stunt design, as I suspect when we all fall off our perches, then control line stunt will probably die too!
Some of the answers have already provided some illuminating example. Lauri was being quite provocative and I suspect making some people think! Other views were very interesting too. I would reckon we have another 20 years or so before stunt becomes virtually extinct. I can't believe that the planes in stunt's "Winter Days" will just be rehashes of current design thinking. Hence the initial question.
If I am still able to fly in 20 years time, I will still be flying IC, as electric is plug and play and doesn't really present many challenges. I was devleloping chopped multiphase electric systems over 30 years ago and found the technology as inelegant then as I do today. That ISN'T a challenge to the electric fraternity. I shall probably be on my own at that stage and classed a dinosaur to boot.
What really interests me is how model design will have changed. is there likely to be any out of the box thinking that revolutionises stunt design, or will it be small improvements along the way?

Regards,

Andrew.

phil c · « **Reply #56 on:** July 22, 2013, 09:59:46 PM »

Quote from: Andrew Tinsley on July 18, 2013, 08:50:37 AM

If I am still able to fly in 20 years time, I will still be flying IC, as electric is plug and play and doesn't really present many challenges. I was devleloping chopped multiphase electric systems over 30 years ago and found the technology as inelegant then as I do today. That ISN'T a challenge to the electric fraternity.
Regards,

Andrew.

Andrew, any thoughts about designing a true, 3 phase ESC that uses the same frequency control used for industrial motors?

Andrew Tinsley · « **Reply #57 on:** July 23, 2013, 03:34:46 PM »

Hello Phil,
My brief interlude in designing industrial chopped "3 phase systems" was purgatory! I certainly don't want to revisit that era! I do take your point however.......no I don't want to go there!

Regards,

Andrew

Author Topic: The ultimate stunt machine? (Read 23449 times)

steven yampolsky