Slow Flight in a Gyro??????

[C. Beaty]

In fairness to CFIs, Dean, the PTS (practical test standards) must be taught for anyone intending to go for PPL. No mortal can move the FAA.

A more useful way of improving quality of instruction would be for gyro CFIs to take a knowledge test in order to obtain PRA certification.

It would require someone to write an instructional booklet that outlines such things as CG/rotor thrustline relationship and its effect on stability. Just think how many CFIs have stated a gyro can’t be tailheavy if the dangle angle is within limits.

 

[Gyro_Kai]

In Germany slow flight is an essential part of the training. Flying at 60km/h (37mph) at 3 ft height over the runway, sliding the plane from left to right, nose straight at all times. Preferably with cross wind.
It was the most frightening thing of my training and I still hate doing it but do practice it once in a while.

Kai.

 

[Dean_Dolph]

In fairness to CFIs, Dean, the PTS (practical test standards) must be taught for anyone intending to go for PPL. No mortal can move the FAA.

Well, from the sounds of things the FAA is close to the edge on gyros so may be all they need is a little shove!

A more useful way of improving quality of instruction would be for gyro CFIs to take a knowledge test in order to obtain PRA certification.

Unfortunately since the 5209 went away it doesn't look like the PRA has much leverage.

It would require someone to write an instructional booklet that outlines such things as CG/rotor thrustline relationship and its effect on stability.....

Uh, yeah; you volunteering or willing to assume at least a consulting/editing role? I could see a team of you, Doug R., Greg G. and possibly others, including Al Hammer and his graphics, dividing the considerable work load and putting somthing together. All of you guys are well respected and carry mucho weight in the community.

Just an aside, what happened to all the articles that you were working on for the PRA magazine? I'm talking about the list you posted way back when. An effort to compile your past articles into one document was started but like a bunch of other good intentions it stalled. That effort needs to shift into another gear!

 

[Joe Pires]

It was part of my training too. I am finding it pretty handing at my new field. I now come in high to keep peace with neigbors and slowfly to no fly into a vertical descent till i am at a good height to make my approach.

 

[dragonflyerthom]

O.K.

Some really good answers. One of the problems I have encountered in my ASI is that it doesn't read the air speed correctly. I have figured that mine is about 10 mph too high. So with this in mind I have adjusted everything up a few mph ie Approach is at 70 instead of 60 ASI. This gives me a better safety margin when I am landing. I haven't found vertical descent a problem but I still haven't done any slow flying. I have a heavy gyro so at the present I don't want to be near the runway until I get back with my instructor. To me slow flying would entail flying behind the power curve with slow airspeed and high ERPM. I will try it one day at altitude. Right now I am trying to trace down a 2 per shake. I replaced the magic bushing Saturday. Mine had melted and cracked in the mast. I will keep ya'll posted.

 

[Doug Riley]

Chuck B., Harry and others: you remember when we learned to fly using towed gyrogliders. This method had its charms and advantages.

One DISadvantage of it was that the available thrust (from the tow car) was for all practical purposes infinite. There was no "back side of the power curve." You could gyroglide all day at 30 mph -- in fact, you might as well stay slow, since you got a longer flight on each pass that way.

This habit of slowness often resulted in a mush-in when pilots converted to power. There are many accounts of "backside" mush-ins in old issues of the PRA mag from this era.

Granted, these accidents (unlike PPOs) usually didn't result in serious injury. They were discouraging and made our activity look bad, though.

I still worry about my former dual students getting into their single-place machines and forgetting to monitor airspeed. I think practice entering and recovering from slow flight is essential. Slow flight has a sound and feel that, once familiar, tells you to speed up even if you forget to monitor the ASI. You can tell you're slow with your eyes closed -- once you know what to listen and feel for.

 

[C. Beaty]

The only critical aspect of slow flight is the fact that below the speed where level flight is possible at wide-open throttle, there is no recovery other than by dropping the nose and picking up airspeed. Insufficient altitude and a splat is inevitable. It is impossible to power out of a sink at an airspeed of less than ~15 mph for a lightweight to perhaps ~25 mph for a hawg. Instructors ought to spend some time drilling this in.

It is silly and a waste of time and money to spend time with an instructor practicing flying on the backside of the power curve.

Below the speed for minimum power, in order to fly slower, more power is required. This is an unstable slope and requires considerable skill to master, balancing pitch attitude against throttle. But proficiency requires practice, not instruction.

Bensen says it much better than I; here’s an OCR from a 1967 flight training manual:


15. APPENDIX I

TO GYROCOPTER FLYING INSTRUCTIONS


The first plot shows two curves, the solid one being power required to maintain steady-state level flight at a fixed gross weight, and the dashed curve shows engine horsepower available at any given forward airspeed. Several points are worth studying here. Observe first that even when turning at full throttle, engine power is zero at zero airspeed insofar as forward propulsion is concerned. This horsepower rises rapidly to the point where at 15 mph it can maintain level flight. Beyond this point the pilot must reduce the throttle to maintain level flight. If he chooses not to do so, the craft will either rapidly accelerate to higher airspeeds, or will climb, or both, depending on what he does with the longitudinal stick control. Maximum excess horsepower occurs at 40-45 mph. Finally, at approximately 85 mph the “power required” curve crosses again the “power available” curve, which means that the gyrocopter here reaches its “top speed” in level flight. Higher speeds beyond this point therefore can be obtained only at the expense of losing altitude, or diving.
The second plot illustrates this situation further by comparing it with an airplane of approximately equivalent horsepower and performance. It can be seen that the Gyrocopter performs
. best in the very area where an airplane quits flying because of stall, at about 40 mph. Further- more, the Gyrocopter never really “quits flying” even below its “minimum level” speed of 15 mph, but continues to fly at a finite rate of descent. Even at zero forward speed this rate of descent is comparable to that of a parachute.

One lesson a new Gyro pilot must learn after studying these curves is this: whenever he finds himself slowing down accidentally or on purpose to 15 mph (or if banked in a turn, to 20-25 mph) , the only way he can check his descent, or initiate a climb, is to dive momentarily to 40-45 mph while opening the throttle wide open. If in a turn, also flatten out the bank as soon as possible. This may seem like an odd thing to do, especially if you are already close to the ground, nevertheless, if you want Mother Nature to cooperate, that is the proper thing to do. Your effort in will power will be richly rewarded by the gyrocopter possessing at 45 mph the rate of climb of ‘a homesick angel”, pulling you out of tightest spots as it heads for the sky.
Also obvious from these curves is the “negative drag slope” below 45 mph, which means that, at a given power setting, the machine will constantly try to either speed up or slow down. To maintain constant airspeed below 45 mph then the pilot must constantly manipulate the throttle up and down to imitate governor action.

Other clarifications of the relationship between the horsepower and the airspeed will become apparent to you at length, if you take time to memorize and study the attached curves. Please note that the curves were drawn purposely not to scale to allow for the variation of performance between individual gyrocopters.

 

[C. Beaty]

Doug, you upper crust folk, driving 450 in³ Buicks and Cadillacs might have thought you had unlimited power but we commoners driving rinky dink tin boxes knew better.

I had a Datsun 510 and my partner had a Fiat 1100 and neither one of us could stay airborne in a Gyroglider at less than 15 mph. The Datsun pulled a lot better than the Fiat.

 

[Doug Riley]

Chuck, I was 16 and 17 when I did my gyrogliding. My tow driver was 15 and didn't have his driver's license yet, but he was -- and still is -- a naturalborn mechanic. He'd been driving since he was 11 or so. He did a great job.

We towed with my mother's (then) new 302 V8-powered Mustang. Yes, it had lots of power. It didn't even feel the drag of a gyroglider that had one 130-pound kid aboard.

At the same time, Ron Menzie was using a low-powered econo car for towing his 2-place glider. It had a standard gearbox with "three on the tree." I don't recall that the glider slowed this car down much, either. The towline would go slack momentarily when Sandy (Ron's wife) shifted up.

80 hp propelling a vehicle by means of gears and tires on pavement is much more efficient than a prop flailing at thin air. Low-powered tow cars worked better than one might think. There was, I think, a possibility of getting spoiled by the relatively greater thrust that you got gyrogliding behind a tow car... even a wimpy one.

With powered dual training, the risk is different. The new pilot may get behind the power curve simply through inattention. He's apt to be distracted by the excitement of transitioning to his own craft. He may also be misled by the lighter control pressures if his gyro is a single place machine.

 

[C. Beaty]

I imagine most of the low airspeed, back side of the power curve splats result from flying by ground reference and turning downwind.

We ground bound creatures simply don’t have the instincts of birds.

Airspeed awareness is an important part of training.

 

[dragonflyerthom]

CB and Doug

This is what the student pilot needs. Please digress more.. If I study this to memory I might remember it

 

[Harry_S.]

Chuck B., Harry and others: you remember when we learned to fly using towed gyrogliders. This method had its charms and advantages.

One DISadvantage of it was that the available thrust (from the tow car) was for all practical purposes infinite. There was no "back side of the power curve." You could gyroglide all day at 30 mph -- in fact, you might as well stay slow, since you got a longer flight on each pass that way.

SO TRUE, DOUG. WE HAD PERMISSION TO USE A MILE AND A HALF OF BRAND NEW CONCRETE, DIVIDED HI-WAY THAT WAS NOT OPEN FOR TRAFFIC. THE ONLY "OBSTRUCTION" WAS THE HIGH POWER LINES THAT INTERSECTED THE HI-WAY ABOUT 1/4 MILE FROM THE NORTH END. YOU WOULD BE DOWN LOW FOR A TOUCHDOWN ANYWAY. THE THINGS I DID IN THAT GLIDER WHILE SOLO, UGH... IF THAT ROPE WOULD HAVE SNAPPED...

TALK ABOUT LONG FLIGHTS...I TESTED THIS FELLA'S PONTOON GLIDER ON A RATHER LARGE LAKE AND I WAS AIRBORNE FOR MAYBE 25 OR 30 MIN. AND WAS HAVIN' A BALL; ONLY ONE OTHER BOAT IN THE WATER. WE HAD NO COMM. AND THE OWNER WANTED TO TRY IT OUT HIMSELF SO, HE STARTED A STEADY SLOWDOWN TO GIVE ME THE MESSAGE THAT HE WANTED ME TO SET 'ER DOWN.




This habit of slowness often resulted in a mush-in when pilots converted to power. There are many accounts of "backside" mush-ins in old issues of the PRA mag from this era.

MY FIRST POWERED FLIGHT WAS IN A USED B7 I BOUGHT. IT WAS NOT DEMO'ED, BUT I DID FLY IT UNDER TOW FOR ABOUT AN HOUR BEFORE I DECIDED TO FLY WITH POWER. AS I'VE SAID BEFORE...I DIDN'T NEED TO READ NO STINKIN' BENSEN MANUALS, RIGHT?!

ANYWAY, I CRANKED 'ER UP AND TAXIIED THE FULL LENGTH OF THE RUNWAY, FACED INTO THE WIND, USED THE "ARMSTRONG" SPINUP, SAT IN AND STARTED SLOWLY ROLLIN'. WITH THE STICK FULL BACK AND FULL THROTTLE, RRPM LOOKIN' GOOD, SHE LIFTED OFF. GOT ABOUT 5-6 FT. OFF THE GRASS AND MUSHED BACK TO THE GROUND. WHAT'S GOIN' ON?!

TAXIIED BACK FOR ANOTHER TRY. IDENTICALLY THE SAME AS THE FIRST ATTEMPT. TRIED ONE MORE TIME...THE SAME RESULT. NOW I'M PISSED. I'M THINKIN' THIS BABY DON'T HAVE ENOUGH POWER TO FLY. I'M STANDING AT THE END OF THE STRIP WHEN IT HITS ME. :boink: THE GLIDER HAD ROCK STEADY PULLING POWER WITH FULL AFT STICK FOR CLIMBING...I DIDN'T.

ON THE NEXT TRY, WHEN I WAS ROLLING AND BROKE GROUND...FORWARD WITH THE STICK...NOSE CAME LEVEL...PICKED UP SPEED AND AWAY WE WENT WITH A SHAKE OF THE HEAD AND A BIG SMILE. LEARNED A HEAP RIGHT THEN AND IT STUCK WITH ME.

Have never had a "mush in" landing...after those first mushy takeoffs and landings. Those were the days.

I do believe every newbee should try to get 10-12 hrs. experience in a towed glider, if only to have fun while learning the basics of rotor control.


Cheers

 

[dragonflyerthom]

The tow glider reminds me of water skiing. Then transitioning to jet skis. Similar but different. I bet it is fun tho.

 

[C. Beaty]

The Bensen flight training manual has a wealth of information for those that take the trouble to read it.

Here’s the sort of stuff that Thom needs to know and reprints are available somewhere:

 

[Timchick]

Chuck,
Do you know where we can find copies of the Bensen flight training manual?

 

[Fl90]

Tim, I have one. PM for details.

Phil.

 

[dragonflyerthom]

Tim, I have one. PM for details.

Phil.

Phil

I would like a copy also. Tell me how I may get it also.

 

[DanielM]

Couldn't someone scan it to a pdf file so it would be easily available to everybody. I'm sure the copyright has expired by now.

 

[Fl90]

I will check on the copyrigt. I was staying private, to keep from stiring the pot. I didn't realize the interest. I'll seewhat I can do about getting it on electronic media.

Thanks, Phil.

 

[kc0iv]

Couldn't someone scan it to a pdf file so it would be easily available to everybody. I'm sure the copyright has expired by now.

Some information on copyrights

Works Originally Created on or after January 1, 1978

A work that was created (fixed in tangible form for the first time) on or after January 1, 1978, is automatically protected from the moment of its creation and is ordinarily given a term enduring for the author’s life plus an additional 70 years after the author’s death. In the case of “a joint work prepared by two or more authors who did not work for hire,” the term lasts for 70 years after the last surviving author’s death. For works made for hire, and for anonymous and pseudonymous works (unless the author’s identity is revealed in Copyright Office records), the duration of copyright will be 95 years from publication or 120 years from creation, whichever is shorter.

Works Originally Created before January 1, 1978, But Not Published or Registered by That Date

These works have been automatically brought under the statute and are now given federal copyright protection. The duration of copyright in these works is generally computed in the same way as for works created on or after January 1, 1978: the life-plus-70 or 95/120-year terms apply to them as well. The law provides that in no case would the term of copyright for works in this category expire before December 31, 2002, and for works published on or before December 31, 2002, the term of copyright will not expire before December 31, 2047.

Works Originally Created and Published or Registered before January 1, 1978

Under the law in effect before 1978, copyright was secured either on the date a work was published with a copyright notice or on the date of registration if the work was registered in unpublished form. In either case, the copyright endured for a first term of 28 years from the date it was secured. During the last (28th) year of the first term, the copyright was eligible for renewal. The Copyright Act of 1976 extended the renewal term from 28 to 47 years for copyrights that were subsisting on January 1, 1978, or for pre-1978 copyrights restored under the Uruguay Round Agreements Act (URAA), making these works eligible for a total term of protection of 75 years. Public Law 105-298, enacted on October 27, 1998, further extended the renewal term of copyrights still subsisting on that date by an additional 20 years, providing for a renewal term of 67 years and a total term of protection of 95 years.

Public Law 102-307, enacted on June 26, 1992, amended the 1976 Copyright Act to provide for automatic renewal of the term of copyrights secured between January 1, 1964, and December 31, 1977. Although the renewal term is automatically provided, the Copyright Office does not issue a renewal certificate for these works unless a renewal application and fee are received and registered in the Copyright Office.

Public Law 102-307 makes renewal registration optional. Thus, filing for renewal registration is no longer required to extend the original 28-year copyright term to the full 95 years. However, some benefits accrue to renewal registrations that were made during the 28th year.

Leon
(kc0iv)