hourglass ,help..........

Aside from weight issues, and/or power issues, given the model is straight etc, what are the biggest factors in a model not perfoming a rule book "hourglass"????
I have a Vector that is within its weight boundary, powered by Aero 36, turns well concerning squares etc. However, the "hourglass" will show all of the model's innate defencies...I have flown models that were overweight etc, and you learn how to fly within the planes weaknesses/limitations; but this Vector seems to be above that issue and I am interested in hearing other peoples thoughts/insights..Of all the tricks, the hourglass will always highlight a planes inadequacies..When you are flying in expert, you cannot afford to present an airplane that will not pull off an hourglass--"Time" is "running out"....thanks DAVID

I can't answer your question but do need to ask just what the airplane is doing (or not doing) in the hourglass.

This might be an interesting thread.

Randy,
Well, Randy, it is the typical not being able to execute a turn that reflects what the plane is capable of turning a corner lets say at 45 degrees or below.
I believe that a plane has to present itself, or be trimmed to exeute an "hourglass" as well as executing a "triangle" etc.., even though the "hourgalss" will tax an airplane to its limit, more so than performing a "triangle".etc...The plane "should" be able corner in front of you, not behind you, at the top of the glass, come down the final leg, with "tension" and hit final corner, with "tension"--the on "rails look" should reflect the whole "trick"..My Vector does not do this...Excellent corner conerning other tricks, except the glass, and above 45 degrees...I am now messing with rudder off-set-Vector has that "airfoiled" vertical fin, no real hook in it..Line rake, etc..motor off-set etc...line length etc...I am experimenting in these areas...Watching Jim Armors' Nobler execute the hourglass is eye-pleasing, the turn on top is bueatiful..However, it seems the compromise here is that the model does not track well--Indicating this:, so in order to get it to turn well above 45, he has a built in "tail" heavy model, which will corner extremely well, but lose in other areas..I have talked to Jim about this, he recognizes this factor, and is willing to live with it...I want to capture this Vector's capacity in all realms...Over the years I have watched "Windy's" planes execute "hourglasses" I believe it is his signiture "trick" and reflects his ability to trim a model around the hourglass maneuver..Knowing, that everything else will fall into place..Just some thoughts.....Thanks David

The hourglass and Vertical eights are the two most consistantly mis-flown maneuvers in the pattern, in my opinion......

The hourglass gets sort of ugly when it is flown correctly....with the horizonal top equal length as the bottom..... it seems to me that even at National (or World) levels, very, very few do either of these at a level that merits more than 30 points.....the eights get to looking like snowmen, and the top triangle is much, much smaller than the bottom....pretty, yes, rulebook, not.

See Ya

>The hourglass and Vertical eights are the two most
>consistently mis-flown maneuvers in the pattern, in my
>opinion......
>
>The hourglass gets sort of ugly when it is flown
>correctly....with the horizontal top equal length as the
>bottom..... it seems to me that even at National (or World)
>levels, very, very few do either of these at a level that
>merits more than 30 points.....the eights get to looking
>like snowmen, and the top triangle is much, much smaller
>than the bottom....pretty, yes, rulebook, not.
>
>See Ya
>
>Peabody

From my research I would say this is correct.

From watching the CL Pattern simulator, not only should the top be as large as the bottom, it should actually appear slightly larger than the bottom due to the fact that it is some 70 feet closer to the judges.

From looking at Nats tapes from several different years, the only pattern hourglass I saw that came close to the simulator would be Bob Baron in 1996 (I know I keep harping on this). His hourglass was the only one that appeared to be not only symmetrical, but sized correctly at the top. The only exceptions would be Al Rabe, (amazing hourglass this man can do--I wish more people could see it) and at times Ted Fancher. This is certainly not to say there have not been others, I am sure there have. I saw one tape with Paul Walker, Fitz, Ted and Hunt. I think it was 1994? The taping was from the wrong angle, but the manuevers all appeared to be very good (those guys were all flying very well at that time, fun to watch). Baron's just happened to be the best I have seen from my own library. In fact, that pattern matches the simulator the best of all the ones that I have seen. There are some great patterns out there from lots of people.

As far as improving the hourglass, let's not blame the airplane so fast. I have been working to improve my own hourglass. I have found, even beyond power, prop, and trim, that moving the manuever ever so slightly to the right increases the ability to turn the second corner, as the airplane is being pushed down into the corner instead of having to fly into the wind, which would result from being to far left. Many people are tempted to get left in the wind to use the boost from the wind to fly the first leg, nice at the bottom, bad at the top.

Could you please tell my about the CL pattern simulator ? I live in the Netherlands and I am looking for any sort of simulator CL to
analyse the FAI pattern. I would like to have one on my computer.

Gerben Wassenaar

Yes..I'de like to hear what prop, fuel, line length, lap time.

I flew an SV-40 (vector) into the top twenty in Advanced at the nats this year and hadn't seen anything that wasn't pilot induced to destroy the hourglass.

And Chris Rudd flew his MUCH better yet.

It is a power manuever tho..and if you hit the first top corner too hard, it can spell trouble.

What IS the weight?

Mine was about 48 oz with the ROJett BSE 40.

This "other" Vector pilot was having issues with plane going soft on top until he realized he was flying the tops way past the vertical.
Another contributing factor was leadout position. It turned out be be too far forward. After he rechecked the CG and moved the leadouts accortingly(I think it was 1/4 behind the CG), the hourglass came to life!

Steven Yampolsky

Paul Smith

Don't feel like the Lone Ranger.

Take some drafting tools and try to draw an hourglass to scale, using realistic radii. It won't look like much the rule book.

LAST EDITED ON Oct-11-04 AT 05:07 PM (CDT)
 
This is where the view from the pilot's perspective changes at the outside of the circle. From the pilot's view point the figures look (should) like perfectly symetrical shapes. From the judges perspective the triangle and hourglass can look very distorted if they are not directly upwind of the maneuver. For example, as the tri or hour move to the right of the pilot (from the judges perspective) both up and down legs appear to get more vertical, but the down leg is most pronounced. I realize that this is not within the question asked, but wanted to note it.

As far as the hourglass goes I can only comment from myown experience. While flying with Curt (CaptCurt) a few weeks ago I had fallen into a trend where I could not fly the hourglass, the downward leg was a long snake wondering off to the right and the last corner was more of a half loop. No my Gladiator is pretty well trimmed and I've flown the hourglass well, so I know it was me. As I studied the manuver I discovered that the problem was at the first corner. I was making the anlge too shallow (turning too far) and when I reached the top I was out of position. In order to make the second turn I had to turn late or I wasn't at the top. This of course made the top leg too long and in order to get back to the correct laft corner point I'd have to fly at about a 30 degree angle inverted or make the last corner way early and the symetry was nonexistant. When I realised what I was doing I began to concentrate on making the first corner correctly and the rest of the maneuver "fell" into place. I proved this later at the Dayton contest where I flew Hourglasses of 32 and 34 points in front of John Sunderland and Joe Rienhardt.

I've never noticed a trim problem in only that maneuver that wasn't also evident in others, particularly the triangle and the cloverleaf, where most trim baddies show their ugly heads.

I currently fly a Tempest 40 and had the same problems. It was really soft at the top and great at the bottom. For me it was three things to get the plane the way I like it. I added 1/4 oz of tip weight, moved the lead outs forward, and worked with props until I got the best drive/feel at all attitudes. This took several flights to get where I wanted. I made the changes in the order listed and was pleased with the results. Good luck.

>Aside from weight issues, and/or power issues, given the
>model is straight etc, what are the biggest factors in a
>model not perfoming a rule book "hourglass"????
>I have a Vector that is within its weight boundary, powered
>by Aero 36, turns well concerning squares etc. However, the
>"hourglass" will show all of the model's innate
>defencies...I have flown models that were overweight etc,
>and you learn how to fly within the planes
>weaknesses/limitations; but this Vector seems to be above
>that issue and I am interested in hearing other peoples
>thoughts/insights..Of all the tricks, the hourglass will
>always highlight a planes inadequacies..When you are flying
>in expert, you cannot afford to present an airplane that
>will not pull off an hourglass

There are many possibilities as to what the problem might be, so I wouldn't even venture a guess. I would strongly recommend seeking out a trim expert and having him take a look.

--"Time" is "running
>out".

It is? What's the deadline?

Deadline is the ground, Brett!!

Clovis?
Chris...

Chris
Yes, I believe so---I do not feel comfortable right now W/equipment..I think I will go and help out etc...I'm going to fly on friday, w/stooge at Whittier in the morning--I have made many changes to the model--Off-set-(rudder)--Randy told me to change fuel to 5%-I'm going to change lead-out rake, also going to take some nose weight out, which will move the CG some.."Wish you were here"--Windy somebody--LOL--Dave Midge or Rick Campbell....I have got some good advice from Rick C...Are you going??? I heard you were not? Work is in the way..The Sepulveda contest was nice--I had 4.6 lap times, insane--Felt like Jimmy Casale-LOL.....He used to fly 4.9 laps, not to bad I must say....
Thanks David

>Yes, I believe so---I do not feel comfortable right now
>W/equipment..I think I will go and help out etc...I'm going
>to fly on friday, w/stooge at Whittier in the morning--I
>have made many changes to the model--

Well, do as you wish, but I would heartily recommend bringing the airplane to Clovis and entering. I'm more-or-less free on Saturday, and I'd be happy to provide whatever assistance might be necessary in trimming it.

Brett

Brett,
Thanks for the interest, I am planning to go on Saturday, and I would appreciate your trim assistance..I think I have some things sorted out, maybe as far as I can go with it.
Brett, it has been a long time since I really went out all out regarding flying/trimming etc...I have the time now in my personal life, I live a very boring existence-LOL--Anyhow, I would really enjoy your help, I hope to see you on Sat. I think it is a 4-5 hour trip for me-I will try and time it so I can put a few flights in on Sat...
Thanks David

Hey Dave & Brett,

How about a play-by-play next week so we get a look at the process? Don't know about the others but I'd like to know about this one.

Thanks,

Ditto for me. I'm very curious.

Steven Yampolsky

>Ditto for me. I'm very curious.
>

Guess it's going to be pretty embarassing when we can't figure out how to fix it, huh?

>Hey Dave & Brett,
>
>How about a play-by-play next week so we get a look at the
>process? Don't know about the others but I'd like to know
>about this one.

Well, guess I staved off embarassment, this time, at least.

David and I met up on Saturday. The airplane was neatly built and reasonably straight. David was running it on very short lines - well under 60, maybe as short as 57. He had also cut the rudder loose from the fin and added about 15 degrees of offset. The leadouts were way far forward. And it was rather heavy, although "power" was certainly not an issue. He flew it and it didn't, surprisingly, look obviously yawed or rolled, nor did it grossly yaw in maneuvers. His hourglass was, as he had mentioned, not great, going way back behind his head and looking somewhat out of control. I figured that it had the "kit Twister disease", where a tremendous amount of offset, with the nose dragged back to tangent with the leadouts, was masking inadequate tipweight.

Then I flew it. Amazingly, no severe problem with yaw motion, and hinging indicating too much tipweright, pretty much the opposite of what I expected. It was very hard to fly level, as well. But, and this was the key, the cable handle with very narrow spacing was resulting in extremely "lagged" response to control input. I could nurse it around the pattern, but my hourglass wound up way beyond my head, too. It was a little hinky in inside/outside and straight/corner transitions, but the controls were so soft around neutral that it was being masked somewhat by the filtering action.

I figured that the problem was misdiagnosed as a line tension problem, when in fact it was a pitch control and stability issue. So we cut the rudder off and put it back straight again, took out about 3/8-1/2 oz of tipweight, put the leadouts pretty close to the center of travel. I also got the 60' eyelet-to-eyelet lines I use on the Skyray, and a solid contact handle. When I flew it again, it was *way* too sensitive for me, and cartainly vastly more sensitive than it had been when David was flying it.

But it was much better in terms of being able to make the maneuvers the right size, and it turned *right now* as opposed to "well, OK, I'll take your input under advisement, and get back to you later" like it had been before. It also wanted to hop in corners pretty signficantly. I figured this was the result of inadequate flap motion for the heavier-than-designed-for airplane, so I took a page out of Al's "Bearcat" article and added and ounce and a half of nose weight. And also narrowed the handle spacing a bit. Flew it again, and it tracked fine, went were it was pointed, and could do consecutive hourglasses as narrow as you would reasonably want. In short, we put the airplane back more-or-less as intended, got the pitch axis right, and fixed a mechanical control compliance issue. And sold a few handles for Carl Schoup!

On this topic, the controls were fairly slow inside the airplane, and the handle was also set to very narrow spacing. The result was that you couldn't get close to full control throws with the handle set. And, the very narrow spacing greatly exacerbated the compliance issue. The wider you set the handle, the less small amounts of "give" in the cable, and the lines, effect the response. If you are going to use a cable handle, make the controls slow in the airplane, and then make up for it with a wide handle spacing. This minimized the effects of compliance. The airplane was significantly tail-heavy, presumably in an attempt to get the response back. But that didn't do much in that regard, but did make it pretty unstable, and sometimes a little "wafty" on the line tension. It was plenty enough for me, but it wouldn't inspire a lot of confidence in the less-experienced.

I'll let David put in his observations on the topic, but I think he was happy with the changes. It was *much* more solid than it was when we started, to my hand.

A few more things I would do, given some time to practice. First, get a smaller venturi and/or more nitro, to minimize the super-aggressive breaking in the maneuvers*. Work up to longer lines, maybe as much as 64 feet, and adjust the leadouts accordingly. These were good ideas yesterday, as well, but with less than 4 hours of daylight left, it was just too much to try all at once. And refine the tipweight and leadouts. It was pretty close when we stopped fiddling with it, but it takes probably a half-dozen flights to make sure the tipweight is just right so that it "flows" through corners. If it was mine, I would also cut the fin off entirely, and put a new one on, straight, and with no airfoil, and the rudder hinged for fine adjustment purposes.

Pretty prosaic stuff, but simple things generally work out well.

Brett

*yes, you could drop the nitro and throw in some head shims, but that kills the overall "power" too much for my tastes.And this airplane is fairly heavy. A smaller venturi and enough nitro to get the "power" back would be much more effective.

Thanks Brett, great commentary. I was most interested in you acessment of the control system. I fought "hoppy" corners until I reduced the flap throw. The Glad only weighs 54 oz at 720 sq in so I could even use a little less flap yet. Still, the airplane is now pleasureable to fly and does a pretty good pattern inspite of the guy holding the handle. One thing I've determined about myself is that way back I picked up the bad habit of flying with my wrist and slamming the corners. I haven't been able to completely cure that (old dog new trick syndrome) so I've decided that on my new ship I'm going to a 4 1/2 bellcrank and again making the rest of the control system adjustable.

Thanks again, good stuff,

Great overview...thanks Brett.

Just a comment on the line length issue. I started my SV-40 on 61' lines and I like to fly no faster than 5.0--better at 5.2-5.3 if the plane will do it. I found that, the SV, slightly overweight, really liked to fly a little faster than I could go on the short lines. I went in steps out to 64' eye to eye. Kept flying at about 5-5.2 laps and the plane came alive--everything got alot better since that response v. speed curve, in that area, is not linear.

Mine had no problem with tension even out to 65.5' as long as I flew at anything faster than about 5.4 sec/lap.

Don't know what Davids plane weighed--mine was 46-48 oz depending on prop and gear combo--I never changed the 1:1 flap ratio. The controls were exactly to plan and I flew with the handle spacing very close to 1:1 with the crank spread. About 3.75:4.0.

Just FYI

Thanks again for the diagnostic analysis.

>Don't know what Davids plane weighed--mine was 46-48 oz
>depending on prop and gear combo--I never changed the 1:1
>flap ratio.

Perhaps I said it incorrectly. The problem was not with the flap/elevator ratio, it was with the ratio of pitch rate to amount of lift available. This can happen with the CG too aft - because with the CG aft, it only takes a little bit of control deflection to get a good pitch rate. With fixed-ratio controls (of any ratio) this means the flaps are also not deflecting very much, so you don't get as much camber in the airfoil, meaning not very much lift. Meaning the airplane has to fly at a higher angle of attack, meaning it has to "recover" exiting the corners - i.e. hop.

Move the CG forward, and the elevator becomes less effective at creating pitch rate, meaning you deflect it more, meaning the flap deflects more, and you get a different ratio of pitch rate to lift.

Of course, you can create these situations with a fixed CG by altering the flap/elevator ratio. But the model was also marginally unstable, and instability is more-or-less unaffected by the flap/elevator ratio - so moving the CG and leaving the flap/elevator ratio alone was a better plan. Maybe. And in fact, it would have been impossible with the stock handle setup (cable handle with very narrow spacing)- because the higher control loads would have made the compliance problem even worse.

This was all explained long ago (1969? maybe), in Al's Bearcat article. We did something similar on Ted "Special Edition" at the W/C. I think we discovered that in that case, it was better off with the aft CG and a higher flap/elevator ratio, but it got whacked before I would say we determined anything about "optimum". The difference in the tails (very high aspect ratio on the Vector, and moderately low on the Special Edition) might be a contributing factor, but more likely, that's pretty speculative.

When I received the airplane from a local flyer, he had given up on it after 5 flights..At least that is what it appeared. The plane would not track, the lines were 62 ft, w/a Bolly 3 3/4 pitched prop. The plane was everywhere but where it was suppose to be..I immediately focused on getting it to track. Nose weight, nose weight, etc--changing props etc.etc...(Also handle spacing) which Brett commented on. The spacing was very narrow..I was trained on hot rock handles I also flew W/Windy handles on the East Coast in the 80's..Windy saw me fly in the late 90's, and immediately took my handle from me (one of those bar jobs, many sliders, etc..)and he gave me one of his personal "spitfire" handle's as a free gift..Immedaitely, I noticed the difference..Short memory I have..
i just want to touch on the critical importance of the handle, and its relationship to percise flying..When Brett mentioned, "Dave, I think most of it is in the handle". Bingo, when he handed me the airplane with his handle-(Fancher type) plus the trim adjustments that were made, Brett mentioned, rudder went back to stock configurations, longer lines, 1 oz of nose weight, remove 1/4 oz tip weight, the plane flew with the responsiveness it is capable of..Handle, Handle, Handle, literally changed the way that plane flew..The side effect of making several changes, especially, concerning line length, slowing the plane down-(I had done that w/prop change-needle adjustment-1 week prior, after experiencing 4.6 lap times) is the fuel economy shifted, and I was unable to fly a
complete pattern which reared its head during offical flight...I proably would have stuck W/that handle not knowing how it was impairing my flying style and ability. One factor was because I had acheived better tracking and some sense percision with it. I had already made handle changes, this was the 2nd different handle. I was searching,almost in the right direction.. The thing to remember is both handles I had used were "bar type"-multiple adjuster knobs etc...These handles may work for some, I just experience far better flight characteristics/percision with "Hot Rock" type handles, I guess I had forgot that. Brett's stunt knowledge base was able to hone right in on the weakness of the imparied set-up, which I believe was primarily the handle..Windy had told me years prior not to use the type of handle I was using.
I have much more to do, to be competitive in stunt the whole package is needed..The lessons learned on Sat have forced me to re-evaluate this reality..
David

>
>>Yes, I believe so---I do not feel comfortable right now
>>W/equipment..I think I will go and help out etc...I'm going
>>to fly on friday, w/stooge at Whittier in the morning--I
>>have made many changes to the model--
>
> Well, do as you wish, but I would heartily recommend
>bringing the airplane to Clovis and entering. I'm
>more-or-less free on Saturday, and I'd be happy to provide
>whatever assistance might be necessary in trimming it.
>
> Brett

Lucky dog!

Brett, when are you visiting Texas. We have Windy and his crew making a yearly trip these days, thanks to RO. It is a blast talking to the guys. Everyone got to fly Misss Ashley BUT ME!!! Argh!

LAST EDITED ON Oct-12-04 AT 10:11 PM (CDT)
 
Good thread.

I've seen a couple of things I'd like to comment on.

First is the reality that this is a horsepower maneuver. (by the way I wrote a couple of long two part articles on flying the pattern a number of years ago that discusse the design and trim of airplanes to fly the pattern. I think they were called the Design and trim of CL Stunt Models or something similar and "Fly Like A Champion" which was published in Stunt News sometime later and s hould be available from PAMPA Products) The subject of trim and flying of the hourglass are discussed in both.

Anyhow, the description of a "horsepower maneuver" must be thought of in two ways. First, you need a power train capable of getting you where you want to go (the simplest) and, second, you have to conserve ... or, at least not throw away ... the energy you've got stored in a four pound airplane going 55 or 60 MPH.

If all the numbers (weight, engine, prop. etc.) say power isn't a problem you need to look at how you're wasting energy. In this case all the energy you're interested in is coming from thrust. Part of this thrust is the energy stored in the vehicle and part is that available from the power train. What is the enemy of thrust? The simple (and correct) answer is "drag". These are the opposing forces at work.

Drag is generally of two forms. "Form drag" which is produced by the shape of the object you're trying to haul through the air and "induced drag" which is the result of producing lift. Increase either unnecessarily and you've thrown away energy that must be replaced by the power train while you're in an inverted climb.

Don't do that!

How do you maximize the energy in the vehicle and minimize the loss thereof. You have to minimize the drag in level flight and use no more lift than necessary to enter the climbing portion of the 'glass than necessary to convince the judges you have, indeed, entered the maneuver.

This means in the first case your airplane has to flying as cleanly in level flight as possible. A straight airplane flying as tangent to the circle as possible. For good info on this read pretty much any of Brett Bucks posts regaring yaw trim, leadout position, rudder offset, etc. If any of that is wrong you are throwing away thrust/energy you could otherwise use to fly that hourglass.

In David's case I'm not real enthusiastic about the leadouts being just 1/4" aft of the CG. Theoretically on a conventional stunt ship in good trim this is too far forward. It is likely masking some other trim deficiency in the airplane and I'll bet bucks on Buck figuring that one out. He's a genius on that stuff.

To control the other form of drag, induced, we want to minimize the drag buildup in the entry to the 'glass. High "g's" mean high drag. Tight corners mean high "g's". If you hammer the entry you're going to throw away energy that even the strongest powertrains might have trouble returning to you given the fact that you've just pulled the airplane into a past vertical climb (the angles of which tell you you've maintained that high g high drag configuration for a comparatively long duration).

Ergo (pontificatorese for "therefore), fly that first corner no more aggressively than you can do without obviously depleting your energy...and certainly no more than experience tells you you can throw at the engine and hope to get back by the top of the maneuver.

Here's a trick, if you're ship is obesity challenged and you don't want to make the entry look like a big bagel, add some energy during your entry. You can do this easily by starting with your arm extended to its fullest and, as you start the entry move your arm toward your body and simultaneously take a step back while giving a control input appropriate to the corner you hope to fly. Both of these motions would get you a "foul" call from a team race official because in that venue what you are doing is called "whipping". Whipping is nothing more than racing talk for "adding energy to the airplane or, making it fly faster". In our case, of course, what you are doing is minimizing the loss of airspeed from our sustained high "g" induced drag.

At the top of the circle when flying the second and third corners be very aware of the same risks of throwing away energy. Too many people "hit" the second or third corners which throws away energy at a really difficult point because the wing lift is acting horizontally and gravity is sucking the airplane down. You've got to keep it flying. Think of "flying" into and out of these corners, not banging them.

Finally, the worst mistakes I see in hourglasses is poor shapes and vertical lines plus the top is seldom parallel to the bottom. This is usually the result of overturning the first corner which makes the climb too flat and makes the top impossibly long (usually resulting in an early third corner overhead instead of to the pilot's left). If they get the climb right all too often the second corner is not held long enough, the airplane flies behind the pilot and he finds himself making one huge split ess to get back to remotely where he started without crashing).

This is almost always because the pilot loses (or never thought of having) any reference to help him define where the corners should be and where the straight lines should head.

I suggest using your body as a reference. Plant your fit facing directly downwind (the center of the maneuver). Start the maneuver by pulling up at your left toe, climb in a straight line to your right shoulder, fly into and out of a 120degree turn to fly directly toward your left shoulder and, when you get there, fly into and out of another 120 degree turn toward your right toe. Finally fly a nice straight line toward that toe and casually pull out of the resulting inverted dive at four to six feet...without a bobble, of course.

The secret to this is to never turn your shoulders while performing the maneuver and to minimize any turning of the head. You must keep your body in theproper relationship to the desired maneuver in order to use the body as a reference. Make sense?

By the way, the more vertical you make you hourglass (most turn the entry way too far and flatten the resulting manevuer to the point that the dive is nearly inverted flight) the easier you'll find that fourth corner (you know, the one the judges are just waiting for you to screw up)to fly with precision.

So, what you need is a "properly" trimmed airplane sucking the least possible energy out of an adequate or better powertrain flying the maneuver in such a way as to waste as little energy as possible while still flying the precise shape by using your body as a reference and, if you need a little "oomph" toss it in at the entry with a gentle but positive "human invigoration" of the energy equation.

Wow, it's a good thing computers don't use ink, huh.

Ted

Thanks, That sounds helpful. Now to put words into action.

Thanks Ted.
Chris...

Ted,

Thanks for validating my diagnosis, I was quite surprized to read your discription of what I was doing. Good to know I get it right sometimes.

My statement:

"I was making the angle too shallow (turning too far) and when I reached the top I was out of position. In order to make the second turn I had to turn late or I wasn't at the top. This of course made the top leg too long and in order to get back to the correct left corner point I'd have to fly at about a 30 degree angle inverted or make the last corner way early and the symetry was nonexistant. When I realised what I was doing I began to concentrate on making the first corner correctly and the rest of the maneuver "fell" into place."

Ted's statement:

"Finally, the worst mistakes I see in hourglasses is poor shapes and vertical lines plus the top is seldom parallel to the bottom. This is usually the result of overturning the first corner which makes the climb too flat and makes the top impossibly long (usually resulting in an early third corner overhead instead of to the pilot's left). If they get the climb right all too often the second corner is not held long enough, the airplane flies behind the pilot and he finds himself making one huge split ess to get back to remotely where he started without crashing)."

YEah Randy:

I felt the same...I kind of mentioned the energy problems of hitting the corners too hard ealy on.

For the original questions tho..we never have gotten a feel for what the basics are with this plane. No all up weight, no speeds, no prop or powertrain info.

Hope Brett can sort it out. It will be intersting to hear what he finds.

Thanks Ted. I got ALOT out of reading your series and also Bob Hunt's on flying the individual manuevers.

Curt,

As we found out though power wasn't my problem it was purely pilot error (incompetence?). Once I got the first corner in the right place at the right angle the 'glass was there. There was never any lightening tension or "loose" turning.

Yep..

Your plane has plenty of poop. My reference was to the question posed in the original post. You were right on in your self-analysis of the trouble you were having.

David wrote
""However, the "hourglass" will show all of the model's innate defencies."""

HI David

The model has no such deficiencies. I have flown many of these and they do all the manovoures including the Hourglass.
The model just seem to me to need trimmning, You said it i s light and straight, so I see no reason yours will not fly well
The Vector 40 has won dozens of championships all over the world including about 5 or 6 U.S NATs titles. I would suggest that you take advantage o f Brett's offer to help you get the plane in trim. I am sure you will not have much problem with it flying the way you want after that.
If I can help in any way , as I told you, please just ask. However there is nothing like being in person when trimming planes

I think David meant that any model that is out of trim will show it in this manuever. Everyone knows Randy's designs are great.

What I know about Daves model is that it is straight, in a good weight range and is powered by an Aero Tiger 36. Dave did some tank work and prop selection and got it to work well enough to fly the pattern. This is the extent of my knowledge of it from phone conversations, but I hope to get to help with it before the Clovis contest.

HI Chris

Thanks for the reply, Its very hard to trim these in email or on the phone
David is a great guy and I hope you and Brett can help him with the trimming before the contest. It really helps to have someone else outside the circle watching trim issues.

Regards

>HI Chris
>
>Thanks for the reply, Its very hard to trim these in email
>or on the phone
>David is a great guy and I hope you and Brett can help him
>with the trimming before the contest. It really helps to
>have someone else outside the circle watching trim issues.

Well, we'll see! Let's just say that experts will be in abundant supply - I would guess we will have 5-6 NATs winners* hanging around without much of anything else. If I can't manage it, I'm sure some of them can.

Brett

* Fancher, Fitzgerald, Walker, Trostle, Whitely, maybe Hunt.

Randy,
I just wanted to clarify something,,Randy the Vector is a great airplane--So is the motor-(Top notch)---I will find out what the issue is on Sat I hope..I would safely say that the majority of the problem is me--I have not flown competetively for some time..I want you to know that i have nothing but positive things to say about your motors or airplanes, and have for a "long" time..I used your motors/ on the East coast back in the 80's and won some top notch advanced contest's---Some great flyers who still fly today. I just wanted to clarify this..This is not something new...Thanks David

>
>Thanks Ted. I got ALOT out of reading your series and also
>Bob Hunt's on flying the individual manuevers.
>
>Curt

Curt,

Thanks for the nice words.

I've had several private messages asking about my articles, including those in Stunt News. I'm unable to provide copies since I'm not a digital file keeper. Would you be good enough to research whether PAMPA products can supply my articles called (as I recall) So You Want to Win, Huh" and "Fly Like a Champion". One of them might have been in my Model Aviation Columns back in the '80s but, again, I don't have any resources to review.

I know several readers would like to obtain copies and if PAMPA products could provide them they'd be very appreciative.

Ted

p.s. Also in my MA columns there was a series called the Design and Trim of C/L Stunt Models that ran for about four of five issues that would be of interest to many as well.

As long as I'm advertising, others might also enjoy reading my articles on the "IMITATION, EXCITATION and TRIVIAL PURSUIT, as well as the more fundamental construction article on the DOCTOR. All of these articles were (typically, too) lengthy and included a lot of my thoughts on stunt aero, trim and so forth. Again, these were all either in Model Aviation or STUNT NEWS.

All of those are available in the archive..

I always thought that your series and a copule of others should be offered as a compendium regarding certain areas of our "game".

I can put the collection together and see how it looks.

Do it Curt, now!!

WOW!

I copied this to read with care.

Great posting, Ted!!!!

Thanks,

>WOW!
>
>I copied this to read with care.
>
>Great posting, Ted!!!!
>
>Thanks,
>
>Ion

You're welcome.

Better yet,

I copied it into the Tips section of the PAMPA website for everyone's benefit.

Steven Yampolsky