I don't think you consciously move the handle, you just think "loop", and the model does it!   Well, thats how it seems with me. And then I think "that was crap"! and try again 

Cheers        Neville

Brian Gardner and Brian Hampton did some tests independently some years ago and the deflections were quite small but I can't remember the numbers.

Perhpas they will tell us how they measured and their results.

Chers, Geoff

I'm setting up airplanes with @ 25 degrees either way.  There is an exposition in one of the Frank Zaic books about stalling the elevator with too much deflection, which actually opens up the turn.  I had an airplane where I could try this, and Zaic was right. 

A couple of years ago, maybe more, Bob Reeves attached a video cam to his plane to watch the flaps and elevator.  It was quite interesting how little movement was needed to fly the pattern.  He also done another with the cam focused on the plastic fuel tank showing what fuel does while in flight.  Wish I still had the link to post.
Lee TGD

Found the image, went through the square corner frame by frame and pulled out the one with max deflection. Not sure you can tell how much it was deflected but here it is.

Years ago I heard that Denny Adamisin did a study using a pencil lead attached to the elevator to mark the fuselage to show max deflection....   As I recall, the max deflection they saw was about 20 degrees....   Maybe Denny or Dave will chime in with the real story...?
I've set my planes up to give about 25 - 30 deg max at the elevator and that seems to work out ok....   FWIW and your results may vary!!
Jim

Sorry Jim, I did not do that kind of study BUT I believe that 20 deg is pretty accurate based on just trying to duplicate how far my hand moves while flying and then back checking after the flight - not terribly scientific I'm afraid.  Like you I want to set the elev for about 30 deg at full crank throw, that seems to result in about the best control speed for me. 

Brian Gardner and Brian Hampton did some tests independently some years ago and the deflections were quite small but I can't remember the numbers.

Perhpas they will tell us how they measured and their results.

Chers, Geoff

Actually I didn't do tests to find out how little elevator movement was needed as such. What I did was to slowly decrease the total travel until I felt comfortable with how it responded to hand movement and how easy it was to keep level, in other words I was just decreasing sensitivity. The rate of hard turns didn't seem to change at all and when I was happy with how it handled I then checked total travel just for interest's sake and found it was 17 degrees up and down. Square turns were still just as sharp as with larger deflections so I'm sure I could have gone even further but I'd achieved what I was looking for.

Then I did the same with flaps to overcome a slight stall on the bottom corner of the triangle and hourglass (I'd had the flaps set for zero movement until then). That only needed 5 degrees either way. What took me by surprise was the extra effort needed with just 5 degrees of flap.

Most builders set up for about 25 deg elevator and flap.  For round loops, very little control is needed.  Many flyers use too much control input and loops turn out egg-shaped after correcting for too much input.  Corners, on the other hand, require almost full deflection but only for a split-second.  The trick is knowing when to back off!

Floyd

Donaldo:
Interesting quandry - Al & Bob - you described.  I do not remember the Humbug(s) as fondly as you do but I do remember they semed to fly much better than anyone expected - just looked awful doing it!

However, look where Al Rabe went after that - 180 degrees out of phase with the flapless concept.  Al's designs evolved to have ever larger flaps with extremely stiff flap structure to maximize their effectiveness.  He also used a large EZ Just that was further extended (wider line spacing) and a smallish 3" bellcrank that maximized his control input ratios.  I remember Al's body language - he seemed to hit the handle hard to max out the control inputs.  I also recall he had a fair abmunt of success (!!!) with his approach.  It would be interesting if we could find similar in-flight pix of some of his birds.

BTW, Al WAS doing well at that NATs and had to miss the finals cuz of work.  That was also the NATs where the Event Director left and my Dad ran the finals...

Yes! Al also took a TON OF RAZZ N' MAAATAZZZ from that line up of traditional Nobler and jet style canopy on the nose folks....
When Al was here in Seattle...I too had the chance to fly that amazing Bear-Cat of his...AND YES..
THAT MODEL GROOVED BEAUTIFULLY, not only that but that model tracked soooo accurately through the rounds...HOWEVER!!!  
YES!
When doing square and hard corners...I almost did a touch n' go...on my first square loop with his beautiful BearCat!!! It didn't take me long to note that I NEEDED A WHOLE LOT MORE HANDLE INPUT...when performing square corners...(IF YOU ARE LURKING AL!...I almost lost bladder control until I found out just how precise and predictable that Bear Cat turned hard corners when you get used to needing more movement from the handle. Speaking his handle. In those days, he used a small HOT ROCK...but open up the spacing open to the max by using a small file and carefully filing the slot to the top and bottom of the exit holes. Then after opening would insert and expoxy inserts to fill the orignial position. From that point on...I followed that advice and all my HOT ROCKS were modified this way also. Sounds  a tad...suspect but never had a handle failure with those insert modifications that allowed a little more leverage to the small spacing of the smaller HOT ROCK.

I will never forget my first take off with that Cat....those long shock absorbing main landing gears...was amazing, as the tail would rise off on the smoooooooooothest and most realistic take off I had ever felt.
And then the landing...WOW! Imagine just how beautiful that Cat of Al's would look from the handle...at the moment of touch down....and then to watch that tail slowly drop down  as it coasts to a stop.
IT JUST DOESN'T GET PURTIER THAN THAT...when watching  Captain ACE AL RABE fly those beautiful scale CLPA models.  With all his exceptional flying skill....then stir in that scale formula appearance...NO WONDER HE HAS WON SO MANY DESERVING AND HARD EARNED AWARDS OVER THE YEARS.
Bottom Line:
As beautiful as Baron's Hummmbugga flew...As far as visual impact??? NEED WE SAY MORE?
After all these years...I still can almost feel and see that Dark Blue & White Al Rabe Bear Cat...still imbedded in my demented damaged old brain cells.  

Thanks for diggin up those beautiful old Humbug photos....Bob Baron was truly an amazingly gifted soul...gone too soon.

The "71 Humbug" is a N30 legal plane.  Are there any plans available for it?    The "regular" Humbug plans are, as well as a kit. It too is N30 legal......BUT the 71 looks , to me , nicer. 

Yep, gotta say it looks better than the original!

I seem to remember that a Veco .19BB was used in the original Humbug, but does anyone remember what engine Bob used in '71?

Big Bear

71' Humbug

Got my plans from Tom Dixon.
BEWARE! This IS NOT the 19 powered Humbug that many are familiar with.
This is a whopping 700 sq"!!!!

The following is a quote from the July/Aug 1998 Stunt News, page 81.
Page also contains three (3) B&W pics of Bob's 71' Humbug.

QUOTE: "Bob Baron placed 4th at the 1971 Nats with this flapless stunter named "'71 (Hum) Bug". It had 700 square inches, 59" span, powered by a McCoy series 21 .40 with a 10 X 6 EW Rev-Up prop. The plane was covered in Monokote, and received very few appearance points. Tom Dixon has plans." END Quote

"Tight Lines!" & HAPPY NEW YEAR!

Wes

Well, I have a Magician with a stationary flap glued in place and it is overpowered by the standards of yesterday. It is the lightest I have ever seen. It turns on a dime and we have in flight shots of wrinkles in my wing covering during square inside corners...outboard tips flexed up to make this happen given the direction of the wrinkles on film.

Personally, I think someone else said it but, we have been over flapped and under powered for years. Speed was not what we were after either. Controlled thrust was given all the lift we were generating and could do nothing with. 3D RC proves this all day long!

High RPM low pitch set-up with controlled revs allows this to be more of a reality. We still have more flap than we need in many if not most cases in my opinion. Evidently the French do too! Im not implying that their minimalist approach is totally correct as it is in the right direction. I dont think I am alone in the belief that our classic era, nominally flapped 3/4 length configuration works better under the best available power than fully flapped to the tip.

The less vortecies we create, the less we have to deal with. Mother nature takes care of the rest by not being AS disturbed. Blow a puff of good cigar smoke through a still room with the blinds open. Take the corner of one blind and gently blow smoke across it to see what I am saying. Pretend you are flying through water at normal speeds and imagine what effect your control inputs given a vector, or current in this case is doing to the air/water.

The squarest corner....is flown by the shortest coupled models flying surfaces. Not so important here.The best definition of a flight path for a given average lap time, flown in a circumference with a steady prevailing wind, and controlled power is the last unknown variable or is it.

Surely we can recreate this scenario of current capabilities in a program. HMMMM.....HOWARD!

Put a 4" bellcrank in a barndoor wing of 20% cord and light wing loading. Say 36 oz. wet and 500 sq." . Give it the additional stationary lift quotient of a stationary flap as drawn and see what you can do in any and all conditions...or most of them. Its like a good profile on steroids....the short coupling does reduce the loads at the handle, and the difference of assymetry now eliminated with an additional half panel out board and nominal tip weight.......well...here we go!

My guess is a mechanical solution to a mechanical problem will solve itself under electric power......on the nose!

Well, I have a Magician with a stationary flap glued in place and it is overpowered by the standards of yesterday. It is the lightest I have ever seen. It turns on a dime and we have in flight shots of wrinkles in my wing covering during square inside corners...outboard tips flexed up to make this happen given the direction of the wrinkles on film.

Personally, I think someone else said it but, we have been over flapped and under powered for years. Speed was not what we were after either. Controlled thrust was given all the lift we were generating and could do nothing with. 3D RC proves this all day long!

High RPM low pitch set-up with controlled revs allows this to be more of a reality. We still have more flap than we need in many if not most cases in my opinion. Evidently the French do too! Im not implying that their minimalist approach is totally correct as it is in the right direction. I dont think I am alone in the belief that our classic era, nominally flapped 3/4 length configuration works better under the best available power than fully flapped to the tip.

The less vortecies we create, the less we have to deal with. Mother nature takes care of the rest by not being AS disturbed. Blow a puff of good cigar smoke through a still room with the blinds open. Take the corner of one blind and gently blow smoke across it to see what I am saying. Pretend you are flying through water at normal speeds and imagine what effect your control inputs given a vector, or current in this case is doing to the air/water.

The squarest corner....is flown by the shortest coupled models flying surfaces. Not so important here.The best definition of a flight path for a given average lap time, flown in a circumference with a steady prevailing wind, and controlled power is the last unknown variable or is it.

Surely we can recreate this scenario of current capabilities in a program. HMMMM.....HOWARD!

Put a 4" bellcrank in a barndoor wing of 20% cord and light wing loading. Say 36 oz. wet and 500 sq." . Give it the additional stationary lift quotient of a stationary flap as drawn and see what you can do in any and all conditions...or most of them. Its like a good profile on steroids....the short coupling does reduce the loads at the handle, and the difference of assymetry now eliminated with an additional half panel out board and nominal tip weight.......well...here we go!

My guess is a mechanical solution to a mechanical problem will solve itself under electric power......on the nose!

I don't understand most of that.  What do you mean by "short coupling"? 

I don't think that Brad's notion of short flaps having less vorticity than long flaps is correct.  To a first approximation, for a given speed and loop radius, power that goes into making vortices is proportional to the square of wing span loading.  It could be that there is something subtler happening, but I couldn't get Brad to show any math.  If you can explain it, please do. 

Your 36-ounce 500-square-inch stunter, unless it has a really low aspect ratio, will have a lot less induced drag (drag due to vortices) than my Impact, regardless of its flap configuration.  The big bellcrank will reduce the loads at the handle, too.  My guess is that its gust response and the absence of direct lift control from flaps will hurt your score, but it will be interesting to see how it works.

I don't understand most of that.  What do you mean by "short coupling"? 

I don't think that Brad's notion of short flaps having less vorticity than long flaps is correct.  To a first approximation, for a given speed and loop radius, power that goes into making vortices is proportional to the square of wing span loading.  It could be that there is something subtler happening, but I couldn't get Brad to show any math.  If you can explain it, please do. 

Your 36-ounce 500-square-inch stunter, unless it has a really low aspect ratio, will have a lot less induced drag (drag due to vortices) than my Impact, regardless of its flap configuration.  The big bellcrank will reduce the loads at the handle, too.  My guess is that its gust response and the absence of direct lift control from flaps will hurt your score, but it will be interesting to see how it works.

By short coupling I mean tail moment. Been flying this thing in profile and classic events for the most part of ten years....not as often as I used to compete and Im not real serious with this either but I have either won or placed 2nd or 3rd in every competition I have flown it. I beat Jim Lynch with his Super Ares at Paducah, Ky a few years ago just a week or so after he won classic at the Nats. He was not happy. Also Kenny Stevens and his very nice Caprice a time or two. It may suffer some but there are a few folks who know it will do the job.

XFOIL and a couple others' experiences seem to indicate that flat, stationary, flaps make a bit better lift than a completely airfoiled section of the same size/shape. At least on these, wouldn't there be more down wash directly behind the wing, which would lower the stab/elevator a.o.a. and therefore add to it's down force, say, in an inside turn? I'm also thinking of all your very sharp-turning combat types. Is it just wing lower loading that sharpens their turns, or is there another reason for the short tail arms? I asume too, as has been remarked, that corners benefit from the quickness in initiating the turns.

Serge, what I posted above was kinda superficial.  I'll add to that, but still keep it superficial, because real numbers require some work. The more lift, the more downwash.  Downwash is destabilizing: you put in a little up elevator, and the downwash acts as even more up elevator.  You could get the same effect from widening the handle spacing.  

Stuff affecting cornering as tail length changes includes:

1. The effect of downwash, stated in the first paragraph above.  Longer tails make this better.

2. Pitching moment due to pitch rate.  This is caused by the change of angle of attack on the tail because of the air being round in a loop, rather than flat in level flight and maybe from the change in direction of the wind on the tail from airplane rotation.  The longer the tail, the more negative pitching moment due to pitch rate is, hence the more stable the airplane is.  Longer tails make this better.

3. Pitching moment due to rate of change of angle of attack.  The tail contribution to this is maybe (according to Etkin) due to the time between when the wing starts making downwash and the downwash gets to the tail.  I would reckon that this effect would make the airplane worse as tail length increases, but I don't know.  

4. Contribution of pressure distribution on the tail to pressure distribution on the wing.  An elevator hinged at the trailing edge of the wing acts as a flap going the wrong way, limiting the lift capability of the wing.  Longer tails make this better, but may not have to be very long to make this evil go away.  Maybe that's why the later, balanced-elevator Fierce Arrows fly better than the original.

5. Tail lift fighting wing lift.  The longer the tail, the less it has to push down to rotate the airplane to the requisite angle of attack, hence the higher net airplane lift capability.  Also, given the stabilizing effects of a longer tail, a longer tail lets you get away with a farther aft CG, hence even less force required of the tail.  Longer tails make this better.

6. Structure and pushrod weight.  Weight goes up fast as tails get longer, particularly if the airplane is designed to withstand indignities such as hitting the ground.  Pushrods get fatter to maintain stiffness.  Longer tails make this worse.

7. Pitch moment of inertial (barbell effect).  Longer tails make this worse, although the leverage of longer tails helps them get the airplane rotating.

8. Ground handling (fitting into cars and shipping boxes). Longer tails make this worse.

9. Reduction in dynamic pressure at the tail due to wing "wake".  If this exists, I wouldn't know how to avoid it without doing some work.  

10. Sensitivity to CG position.  The stabilizing effect of a longer (and larger) tail let you get away with a wider CG range.  Longer tails make this better.

I had some of this stuff in mind when I came up with the Nemesis II combat plane as a kid.  It had a way-longer tail than its contemporaries.  I think the main things I had in mind were items 1., 4., 5.,  and 10. above.  I found 1. in a library.  I knew about 4. and 10. from a flying wing I made, which sucked.

I persisted in having longer-tailed combat planes than most.  A Dane was teasing me about my Snort having a long, vulnerable tail at the 1990 world champs.  He said he would cut it off.  I thought that would be difficult for him to do with the Snort behind his plane nibbling his streamer.