5-foot radius turns.

If you have a tight turning airplane, try this experiment and tell us what you observe.

I'm sure that specialized planes can be made to make the 5' radius corner specified in the PA rules. However, unless it was a plane that could be made to do this 5' corner at an acceptably slow speed, so that the pilot could actually control the corner, I doubt it would catch on. For now, we just try giving an illusion of doing a 5' corner with larger aircraft. The modern PA aircraft are closer to the 5' radius than before, but I beleive they are still in the 13-17' range. As to why the 5' corner is still in the rule book, I don't know. I guess there isn't anyone brave enough to propose a change to it! I don't think a change would be beneficial or needed however.

I don't disagree, but why have it in the rule book since 1957 (thats 44 years now Guys, and we still can't!) if you can't do it? (Generic "you" there).
A Combat model with no flaps will probably turn it without any sweat, a PA model won't. The difference is in the wing loading/power/weight ratio. Of course models FAR exceed full-size aircraft in any respect on this (power to weight to area ratio), but a good Combat ship will beat any full house PA ship any day when it comes to tight corners.If we wanted to adhere to the rule book, we'd all fly ultra-light, adequately powered, tight cornering models, and to heck with appearence points.
Anyone for putting a trike gear on a Russian Combat ship???

All just for grins,

JK

But a combat type plane can't even fly straight and level (constant 5 foot height for two consecutive laps) much less stay on track during maneuvers. That's why we are flying two different types of planes.

I probably couldn't fly a good fast combat plane well. And even a lot of good combat flyers couldn't fly a precision stunt pattern well. (Some like Howard we won't talk about.)

But, when you are talking precision stunt, and you want a plane that will track straight AND turn tight, then you are most likely talking flaps. Even the rules makers in old time stunt give a bonus to non-flapped planes, acknowledging that even with the limited amount of square maneuvers, the flapped plane should have an edge.

A properly designed and built coupled flap plan will give you a sharp, crisp corner, while, also, giving you that steadiness and smoothness needed to perform ALL of the maneuvers in the precision patter (which is a lot more than just square corners). In order to be able to turn the sharp corners with a non coupled-flap plane, you will need to give up too much stability (or fly to fast, or...)

As I said, that doesn't mean that for just a general all-round sport plane a person can't have fun with a plane without flaps. But your aren't going to worm your way into the top 5 at the Nats with a Flite Streak or the latest Kwick Kutter Kombat Kitten.

Leonard,

That is not necessarily so. Bill Netzeband filmed and measured all this stuff many years ago. It demonstrated what I was already aware of; that a properly trimmed Combat ship with low wing loading will turn circles inside the best stunter AND groove also, properly balanced, no flaps required. If you have one that is "twitchey" it isn't dialed in right. His "Barecat" was an attempt to get as close to a 5' radius corner with a Stunt type model as one can get, and Bill was something of a Combat/Stunt designer of merit himself as I recall.
I note that GMA's favorite demo airplane for really showing off how C/L can be done was a Flite Streak with an Ollie .15 diesel, 15 degrees motor offset, light, and no flaps.
Point is, it doesn't seem to me that we are really interested in "Precision Aerobatics", just in what "appears to be" or "looks like" it is "close enough" to the judges. If that really is the case, why don't we just go back to calling it Stunt, and just enjoy it and each other's companionship, as is done at VSC?

The way the rules are, and I support those rules, those 20 appearance points are important. The last contest Matt attended, he came in second with a 532. But with "real" judges doing the scoring (Art Adamisin being one) there were only something like 6 points separating the 2nd through 7th competitor in expert that day (11 total contestants.) I don't know where Matt scored in appearance points compared to the others, but you can bet they were important to someone in the final placement. And it was appearance points that kept Todd out of the top 5 this year. If Todd had had a few more (he only received 10) Windy would have finally broken his 5th place jinx.

But a concours finish on a 650 square inch plane can be done from bare wood to final polished clear coats in 7 ounces. That's not a lot considering the size. It would take very little to do that on one of your combat planes. That's not the point. In Precision Aeronautics the combat plane would not be competitive even in the hands of an expert flyer. And an expert combat flyer would certainly not be competitive with a PA plane.

A combat plane (this is not to say a flapless plane) is not stable and capable of tracking a precision maneuver (and, yes, that word is repeatedly used for a purpose) needed to score properly in our event. And Bill Netzeband's flapless designs were (are) not fully competitive, either. Bob Baron tried one just a couple of years before he won the Nats with a heavy (yes, overweight) coupled flap design. The year he flew with the flapless design he made the top 20 and flew some beautiful round maneuvers. The squares were not.

Bill Netzband always claimed that if he had developed it, he could have come up with a competitive flapless design. Maybe. But, in my opinion, it would have taken something radical.

There isn't a lot of value in arguing a point that "my design is better than your design." The comabat plane is a purpose built plane as is the precision aerobatics entry with coupled flaps. And you can be certain that if there were a better (simpler, easier to build) design that were fully competitive, it would be out there flying at the highest levels of competition. I await you or anyone else to bring it to our attention by flying it before the judges at the Nats (or FAI competition, or some other regional competition where true competition exists and the judges will have reasonable competance.) Then we shall see.

Leonard, I never once said I didn't like Precision Aerobatics, or Stunt flying. I said I didn't like competition flying, and that is a whole different ball game to me. The airplanes and all are great, I have a bunch of Stunt kits sitting in my kit stash. By the way, I am still going to try to get to that Stuka 630 (Stuka 2000?) this year, I have to order the wood for it yet.
I think Bob Hunt was looking at unconventional designs with his "Klingon" that he mentioned in FM several years ago. I don't know if he ever developed it further or not.
As to this:

"A combat plane (this is not to say a flapless plane) is not stable and capable of tracking a precision maneuver"

That one I will have to disagree with you absolutely on. It depends on what model, and how it is trimmed. I have seen and flown Combat models that went around like they were on rails, and tracked where you pointed them. It all depends on what it is, and the pilot's reflexes and flying style.

See ya!

John K.

Whoops! got a double post in there somehow, sorry!

See ya!

John k.

Flaps provide two things: direct lift control and high max lift coefficient. DLC makes it much easier to fly accurately and to align the body with the flight path. The three truly world-class (with the record to prove it) stunters I've flown were also the easiest control line airplanes to fly that I've ever flown. They'd make excellent trainers. High CLmax makes an airplane turn tight, but it also provides relative immunity to gust inputs compared to wings with the same lift, but lighter wing loading. As for the ability to turn a five-foot corner, I have seen one of these planes level out from a wingover at five feet after initiating the turn from what appeared to be six. It was a very convincing illusion.

If you think a combat plane can turn a 5-foot corner, calculate the lift coefficient required and show me an airfoil that will do it. Should combat planes have flaps? Maybe. Marvin Denny and John Carr both had success with flaps in combat. From Wortmann airfoil data, I calculated in 1976 that to break even in drag on a given size loop (not counting the DLC and CLmax benefits mentioned above), I could afford 1 1/4 oz. for the flaps. I decided that it wasn't worth the bother for planes that don't really last that long.

The way Howard flies squares with his IMPACT is with minimal rad turns usually without a bobble (I like it like that:) Howard's test/practise flight at C.O.L.D. 2000 during lunch break just knocked my socks off. I could not see any radius! I think this is the "eye deception" that Jim T. is referring to, but it's likely the pilot will see more radius than observers. I'd love to see a video of Howard's corner run fairly slow with a 1' grid just outside the circle or superimposed by computer somehow. Let me know if you need me to push a button or something! Steve

OK, Howard, now you have got my curiosity up. If you learned that everything you knew before was wrong, then you must have learned a lot of new stuff that you could share with us. Share, please. Since the trimming process is NEVER done, I am willing to learn new tricks along with the rest of the forum people here.

". . . align the body with the flight path." Rather the alignment of the body creates the perceived flight path. The body of the plane will be pointing straight up long before the turn is completed. This is what I observed. See why an unflapped airplane can appear to turn tighter than a flapped airplane? When you almost make a decending square corner near the ground, you can scrape the rudder or break the tail off because the airplane is not alligned with the flight path (been there, done that).

It seems to me that what has to happen in making a 5-ft radius turn from horizontal to vertical is this. The wing (and rest of the airplane) has to generate enough lift/drag horizontal component to slow the airplane's horizontal motion from flight speed to 0 in 5 feet. While doing so, it has to generate enough vertical lift component to get the airplane back to flying speed within 5-feet vertically. Is this the case? If so, what sort of lift/drag numbers does the wing have to generate for a stunt ship or a combat model? Do any present day stunt or combat models accomplish this? It is beyond my capability to do more than ask.

It's in absolutely front row concourse shape still, and is in perfect trim, if there is such a thing. I have tons of power with the typical Supertigre in the front.

When I compare it to my current PA ship, an SV-11, there is no doubt which will corner tighter, the Humbug wins, hands down.

Now, do I like the way it turns? I'm not 100% sold. Minus the flaps, it tends to corner more like a Smoothie than a Nobler, if that gives you any thing to relate to.

It was mentioned before that to do a 5ft radius, perhaps you needed to slow the plane down and accelerate back out of the corner to achieve it. Well, without flaps, the Humbug does not slow down much, but it sure does accelerate out of the turn. This can be difficult to control, and is a testament to Bob's flying abilities to do as well as he did.

I have noticed that the Humbug does wonderful rounds, and even I can make it do very nice squares, but the 120 degree turn of the triangle and the hourglass are more difficult for the plane. Don't get me wrong, the plane will do them, I just don't think they look as pretty, even when you do them correctly.

I guess that's what it comes down to really. What ship gives the best appearing flight to you, all other things being assumed done correctly, like intersections,45 degree, 5ft bottoms, overlapping, no bobbles and so on... you would think two flights with different air ships done correctly should bring the same score, but I think this is still a very subjective event. The judges still have to perceive a certain flow or precision to a stunt that they like.

I'll give you an example... Get in the wayback machine and turn the clock to 1985??? I saw Tom Dixon fly his Big Tbird 60 at the KOI. It was the smoothest, accurate, most graceful thing I can remember. Almost everything about that flight looked great to me. When I said this to another observer he said, " Yeah, it was good, but something didn't look right, either the plane looked to big on the lines, or he was flying too big, or something, it just didn't look right."

The difference was, even though Tom flew great, this fellow had a set idea in his mind of how a stunt plane in flight should look, and this wasn't it. Now if he had been a judge.... do you think it would (or should?) have effected Tom's score?

Anyways, those are a few thoughts and I've blathered on long enough here,
EricV

We should be very carefull of what we wish for. The day that happens, we may lose more than could ever be gained.

How would most people like a computer juding a Pie or Cake at a Bake Off??? It might be technically a great pie, but would it really taste good??? Then we all get stuck eating crappy pie cause the computer liked it!

As to the problem Bear is trying to address, I think there will alway's, in any event, be people that are near a "profesional" level and will have more resources (said money) and time to invest.

To placate myself, I just go into it with an adjusted attitude...
I tell myself:
"I'm a busy guy with limited time and resources that happens to like PA, I only get to fly weekends, and if I go to a contest and place even remotely near the "top dogs", I should be pleased. Heck, more like shocked!"

I guess the problem arises at the next level. Say I invest more time and effort into climbing the ranks, and I loose 1st place by a whisker to one of the "top dogs". Probably will be harder to swallow, and leave me wondering where I lost that 1/2 of a point that cost me 1st place.

Can anyone who flew "waybackwhen" remember any of these issues coming up when flying in front of the Navy judges???

I agree with Bare. Eventually, like it or not technology and change will arrive, as they do in all things. The task ahead is to try and make any change positive and beneficial.

The first published version of the Humbug had a Veco .19bb, and the second published version had an OS .28 if I remember correctly. What "typical Super Tigre" does the '92 version have, how big is it, etc? Interesting design series! Steve

To answer Tim's question, I only chose the Smoothie as a rough comparison. I could have said a Voodoo compared to a Ringmaster.

In my opinion, since I've had both, the Smoothie is a better Fox 35 airplane for the sport flyer. Chances are, if you get into trouble at the bottom of a vertical eight, the Smoothie may save you, where the Nobler (they can be a little heavy and underpowered with a Fox 35 for those new to building a light stunt ship) might have you pulling the wheels out of the wing. Something I used to do regularly as a kid with my Ringmaster. In hindsight, I guess it was a porker.

Something Commander McBragg would never admit!
EricV

Eric,

I've been lurking on this thread, and reading with great interest, since I have nothing to contribute to this topic (I can't yet even do a loop properly), but now you've piqued my interest. Please elaborate on the difference between a Smoothie and a Nobler in terms of the way they corner. I'll be building a Smoothie this winter, and maybe a Nobler the following year, so I'd love to know what the difference is.

>
>I'll give you an example... Get
>in the wayback machine and
>turn the clock to 1985???

The Wayback Machine?!?!? WOW! Talk about taking me back! "Now, Sherman, don't get your knickers in a twist..." "But Mr. Peabody!"

LOL!