CarterCopter Back In The Air

[Rando]

The CarterCopter folks, who have been grounded since their one-and-only flying technology demonstrator crashed last June, were back at the show yesterday with some new ideas. They showed off a new design for a smaller version of the gyroplane, which they hope will fulfill the dream of a Personal Air Vehicle. "This aircraft will allow true point-to-point travel," said company president Jay Carter Jr. It will have four seats and cruise at about 200 mph, and pilots can land in hotel parking lots and fuel up at automotive gas stations. To test their theories, the company flew to the show in a small one-seat gyroplane, stopping at several parking lots along the way. That aircraft was built from a stock gyroplane with Carter's own prop and landing gear added. The new four-seat PAV design is already under construction and should be flying within the year, and ready to show about a year after that. The company plans to build three copies at once to avoid the lengthy delays that plagued their prior research anytime their one and only demonstrator was down for repair or refit.

[Rehan K.Janjua]

Hello Randy.

Carter copter is definatly nice, but they have taken so long to come up with an practical aircraft.

Is Mr Larry Neal still there test pilot? May be he should give some of his wonderful ideas to Mr Jay Carter Jr.

It would make lots of difference.......just my 2 cents.........

Thank you for the info.

Best wishes.
Rehan

[PW_Plack]

Rehan,

I'd bet the small single-seat gyroplane they describe, with Carter's prop and landing gear technology, is probably one of Larry's Monarch machines.

[Hognose]

Rehan, and Randy

One reason that the programme has taken so long (12 years of CCTD, 7 years of flying) was with only one ship, every time the engine blew (many) or the ship pranged (a couple) or Jay Carter got a wild new idea (practically every day), the machine needed rebuilding and the flight test program stopped. Multiple machines might help but right now the plans seem to involve a different powerplant in each machine!

Carter Aviation Technologies is flying a gyro they call the CarterGyro Demonstrator/Trainer. It is essentially a Monarch with some radical changes:

1. 23' Dragon Wings replaced by 26' DWs (for now).

2. Prop replaced by Carter composite scimitar with two positions (zero thrust and full). The position toggles at 3500 RPM, the zero thrust position is used during prerotation.

3. Strong mechanical prerotator. The aircraft can jump t/o or VVSTOL take off (VERY VERY STOL).

4. Larry's landing gear replaced by Carter version, incorporating Carter's patented SmartStrut in a simpler gear for the mains. The nose fork is made of bicycle parts from a BMX and a mountain bike. the aircraft can make vertical landings from arbitrary heights, and has demonstrated absorption of 3.5 G on impact.

5. Larger (and somewhat odd-looking) seat tank.

Carter continues to work with Larry Neal on some projects. I thought five or six pilots flew the CCTD including Larry, Brad King, and Don Farrington (RIP). George D. Mitchell is the test pilot for the CarterGyro program.

Contact! Magazine's April/May 2006 issue is full of technical details about Carter's programs. I'm working on a news story but it will not have as much detail as the mag does -- hats off to Pat Panzera for a great job. Carter's folks wrote most of the articles, but Pat had the sense to ask for them, and then edit and run them.

cheers

-=K=-

[Aussie_Paul]

Good news.

Aussie Paul.:)

[Jens]

http://www.cartercopters.com/ctd-t_flight_testing_2006-01-15.html

Very convincing gyro - look like that rotor can take the gyrocopter to new and another level.

As I have understood it, they use only a prerotator (on ground) - no power on rotor in the air?

But their landings and slow flights looks to me, as if they have power on the rotor.

[Brent Drake]

it does appear to have a rotor power, looks like a drive shaft of some sort

[Chuck Roberg]

I watched all the videos. I'm impressed.

[Wilson]

Their Demo machine seems to get it's short take off distance from a strong prerotator and an interesting looking, adjustable pitch propeller to kill the thrust during spin up.

[Hognose]

Just came from Choppertown where the CarterGyro is on display and (by now has been) flying. George was catching a nap when I went by the booth.

Jens -- power to the rotor only in prerotation, no power inflight. This is not like DeGraw's rotorsystems (as used on LFINO) where they have fulltime partial power.

Brent -- the shaft is a prerotator, the rotors are unpowered in flight.

Woody -- you're right. The prop has two pitch positions, flat (used during prerotation) and full (inflight). With the prop flat the rotax can deliver 35% of its power to the main rotor.

cheers

-=K=-

[Jens]

Jens -- power to the rotor only in prerotation, no power inflight. This is not like DeGraw's rotorsystems (as used on LFINO) where they have fulltime partial power.
cheers
-=K=-
That is and was also my understanding.
And the beautifull landings, are they just due to head wind?
Or do they speed up the rotor and use that energi at landing?

[Luc De Keyser]

Jens,

From what I heard, there was some light headwind when shooting the video's. However its speed was not measured.
The rotor is not accelerated by the shaft before TD; just your classic landing techniques for rotor speed management.

Luc

[Mike G]

So what is the trick to this very short take off?

Is it

a very strong head wind?
a very high speed pre rotator?
a very high thrust from the prop after pre rotation?
a very light machine?
an over powered engine?

Surely this is what we are all looking for, a virtually zero roll take off without all the complications of variable pitch rotors and jump take offs.

Before joining the forum, I always thought that the missing link was a very powerful pre rotator but this seems to have been rejected by the more experienced members.

What is the secret?

Mike G

[Jens]

So what is the trick to this very short take off?
Mike G

As I understand it, there are tipweights, 2 position variable pitch, high rpm's by prerotating at 0 dg. pitch and then you give it full pitch - and 'upps' your are flying :)

Rather simpel - I think.

[Mike G]

Jens
From the rest of the thread it doesn't look as if there is a variable pitch rotor, so the concept of pre rotating at 0 pitch wasn't used. There is a variable pitch prop.
Nobody in the thread mentioned tip weights before but I don't see how they would make such a difference. In the film the gyro takes off so quickly after releasing the brakes that the rotor doesn't have much time to slow down.

Is the answer a very powerful pre rotator and a high pitch angle?
The high pitch angle would allow the gyro to fly slower and hence take off in a shorter distance but would require a very powerful pre rotator to get it up to speed. Tip weights may help keep the speed after releasing the pre rotator since the high pitch setting would tend to slow the rotor down more than a "normal" setting.
This could explain the need for a zero pitch prop that would be required simply to get enough power available for the pre rotation.

What do the experts think?
Mike G

[brett s]

A good prerotator with that neat two-pitch prop allowing the engine to send more power to the rotor, plus very light disk loading + highly efficient blades & a slight breeze.

[Mike G]

Brett
If it's that simple why doesn't everybody do it?

MikeG

[Jens]

I have copied the following from the Carter Home Page

http://www.cartercopters.com/faq-general.html#question8b


"It is spun to an rpm much higher than the rpm the rotor will be operating at in flight (for exapmle, the rotor on the CTD-T will need to spin at about 300 rpm in flight, but will be prerotated to 600 rpm for a jump takeoff). This extra rpm stores quite a bit of energy, and with the tip weights of the Carter rotor, makes for a very good flywheel. During prerotation, the rotor is set to a flat pitch, both to keep it from producing a force to lift the aircraft, and to reduce the induced horsepower, to allow it to be spun to the highest rpm possible. To be able to put the most power into the rotor as possible, it also helps to have a variable pitch propeller, so that during prerotation, the prop can be set to a flat pitch where it doesn't absorb much of the engine power. When the rotor is at the desired rpm, the pilot will disengage the prerotator, increase the pitch of the propeller, and then increase the pitch of the rotor. The lift created from increasing the pitch on the rotor causes the aircraft to jump into the air,........"

I think I have understood something correct - this time.. :)

Again, it surely looks good on those videos.

[brett s]

The one we're talking about here doesn't have adjustable rotor pitch in those videos. They do state that the winds were 8-10 mph, combine that with the light disk loading & the ability to prerotate to almost flight rpm - that's all you need.

[Jens]

Okay Brett, you are right - I think.
This is also copied from Carter Homepage:

"In this case, we were demonstrating our landing gear and our propeller which will be integrated into the PAV. Originally, we had hoped to have our new rotor on the CarterGyro to show our jump take-off capability, as well."

That should mean, they can do jump take-off even better!

Don't look like variable pitch on this CarterGyro - I must admit:
20996

[C. Beaty]

The one we're talking about here doesn't have adjustable rotor pitch in those videos. They do state that the winds were 8-10 mph, combine that with the light disk loading & the ability to prerotate to almost flight rpm - that's all you need.
You overlooked the most important ingredient, Brett: Pilot skill.

[C. Beaty]

The Autogiros of the 1930s could apply 20-30 HP to the rotor without the need for a feathering propeller; unlike highly tuned 2-stroke engines, the old radial engines had a considerable surplus of power beyond that required for driving the propeller at speeds just above idle.

The torque reaction of the rotor drive passes through the rotorhead gimbal pivots on its journey to the ground so that anything beyond 5 or so HP requires either a rotorhead lock or a stick lock during prerotation.

The residual force in the control system of a tilting head rotor is equal to the tangent of ½ the tilt angle times driving torque.

[Hognose]

Chuck,

it's ten to four in the morning, and I hope that's why I'm not understanding you completely.

I agree totally on the surplus of power in the old radials or the Kellett-Pitcairn era. Also on the display of skill by George.

However, I did not observe a stick lock on the CarterGyro, and am quite clear that they said the machine could deliver ~35 % power to the rotor for prerotation. The 582 makes 65 HP for takeoff.

To all, the light disk loading Brett refers to is a product of longer DWs.

Jens had been working with the description of what is planned, not what flew at SnF. However, the team's intention was to install the Carter rotors immediately on RTB.

My understanding is, the Carter rotors will be lower mass than the DWs but significantly higher inertia. That's because a lot of the mass will be concentrated at the tips.

cheers

-=K=-

[Mike G]

Chuck
I'm glad you've joined this thread I need your experience.
Surely the take off in this film isn't just pilot skill!!
I understand this is a pretty standard butterfly with a different pre rotator and a variable pitch prop.
My understanding is that if you pre rotate to near flying RRPM the rotor develops enough lift to lighten the weight on the wheels and allow either the prop thrust (if fixed pitch) to push the gyro forward or the counter torque from the pre rotator to start the gyro rotating in the opposite direction or a combination of both causing the gyro to become "skittish" as Aussie Paul called it in a previous thread.
We can see in the film that the gyro becomes light on its wheels as the rotor is powered up so I suppose the rotor was spinning very fast and developing a lot of lift.
My question is still how was this take off done and why can't we do it on any other gyro by adding a variable pitch prop and powerful pre rotator?

When you talk about "tilt angle" which angle are you referring to? Could you please make a sketch to explain your trigonometry?

Mike G

[Mike G]

Kevin
I must have missed something, what is the length of a standard Butterfly blade and what is the length of the blade used for the take off in the film? To put it another way what is the reduction in disc loading between the standard rotor and the rotor used in the film.
I'd still like to know what rotor blade pitch was used.

Personally I don't see the need for going to the complication, cost and pilot training necessary for a jump take off if I could make take offs like the one in the film by fitting a variable pitch prop a more powerful pre rotator and longer blades. Unless this sort of take off requires more skill than a jump take off.

Mike G

[C. Beaty]

When being prerotated, the torque applied to the rotor is resisted by the friction of the tires resting on the surface. This torque runs through the rotorhead gimbal pivots on its way to the tires.

If the rotorhead gimbal has an angle, a component of this torque must be resisted by the cyclic control system.

Most people with strong prerotators have observed that when the prerotator is abruptly engaged, the stick is snatched to one side or the other, depending upon gimbal angle.

All the 1930s Autogiros had stick or rotorhead locks that had to be engaged during prerotation.

It’s the very same reason that one doesn’t find tilt head helicopters except in the special case of co-axial rotors where there is torque cancellation.

[Mike G]

Chuck
I'm not sure I follow your trig, I get T*sin (tilt angle) but I'm probably missing something.
Anyhow this doesn't answer the question of how this gyro takes off in such a short distance. If it is just a matter of a beefed up pre rotator and a variable pitch prop (plus a skilled pilot) why hasn't it been done before?

Mike G

[C. Beaty]

I neglected to say Ø/2 is caused by the non-uniform velocity/torque of a Hookes joint. You would be quite correct if dealing with a CV joint.

If the mast was tall enough that the rotor could be tilted flatside to the wind, 8-10 mph would get it to flight rpm without a prerototor.

Many skilled pilots make the kinds of spectacular takeoffs pictured here with sufficient wind and in gyros with high power to weight ratios.

I imagine this kind of takeoff is all in a day’s work for Birdy in Oz when he has a good breeze.

[Mike G]

Thanks for the clarification re Hookes joint.
So for you this was just a party trick with a high power to weight ratio and good pilot, the fancy prop and pre rotator being smoke and mirrors?
Thanks for keeping me straight, looks like I'll just have to get some experience.
Mike G

[C. Beaty]

A compelling argument can be made for strong prerotators and the only way of obtaining more than a few HP from a tuned pipe 2-stroke is to remove the propeller load via a clutch or feathering prop.

There is no substitute for high power/weight ratios.

The kinds of scramble takeoffs depicted in the film clips require considerable pilot skill; keeping the thing under control on the backside of the power curve.

The average Joe Klutz pilot would roll things up in a ball attempting this sort of takeoff.

[Hognose]

Ah, some things start to come clear in my mind.

The head on the A&S 18 and the Pegasus do not gimbal. Neither Dick DeGraw's rotorheads. Describing how he does a jump takeoff in LFINO, Dick makes it sound easy... but Dick is so relaxed, he makes everything sound easy. Of course, LFINO does the reverse, it unloads the rotor to spin it up and then loads it w/collective to jump. The aircraft is powered by Soob and uses a differential to power the rotor with a fixed percentage of engine power at all times. (Chuck has explained how this works in Rotorcraft. Chuck, I sure wish I had really studied that article before talking to Dick at BDs).

if you have seen many of the jump takeoffs of the late, lamented CCTD (and I think, Chuck, you have) you have certainly seen one or two where the pilot had his work cut out for him. It did *not* look easy. And everyone who flew that was a pretty damn good and highly-experienced pilot.

Mike, the two-position Carter prop is really a clever idea on a lot of levels. Get the issue of Contact that talks about the Carter technology, well worth it.

The Monarch comes standard with 23' Dragon Wings, the CarterGyro is flying with 26' DWs. Longer rotors = more lift + more drag + lower rrpm + more vibration. They'll also weigh a bit more. Those rotors were a stopgap measure and they should have the new rotors installed now.

cheers

-=K=-

[C. Beaty]

Wallow flight is not easy.

When doing a scramble takeoff as depicted in the Carter film clips, the gyro is initially wallowing on the backside of the power curve where everything is mushy and the cyclic feels like it’s stirring a tub of molasses.

The same is true of a jump takeoff.

Pilots like Dick DeGraw and the Carter pilot make it look easy but it’s not.

Ken Brock was a master of wallow flight as is Dave Prater.

[gyroplanes]

It’s the very same reason that one doesn’t find tilt head helicopters except in the special case of co-axial rotors where there is torque cancellation.
Chuck,
Wasn't the Scheutzow (sp?) Bee a tilting rotor helicopter with a tail rotor?

It's been a while but didn't Webb Schutezow(sp?) sucessfully fly a tilt head helicopter 25 years or so ago? and wasn't the design sold to someone in the famous "Hunts" catsup family, Bucky Hunt perhaps?

I'm sure you'd remember this one Chuck.

[C. Beaty]

Afraid not, Tom. The Scheutzow B was a conventional helicopter with some novel features. Reduction drive was via a gang of Vee belts at the rotorhead and engine driveshaft coupling used Plymouth pot style “U” joints. The tail rotor drive used a Corvair type fanbelt arrangement rather than a right angle gearbox.

One of the prototypes stood in Ernie Boyette’s front yard in West Palm Beach for quite a while but that’s another story.

I chatted with Webb Scheutzow at Sun-N-Fun shortly before he was struck down by a fatal heart attack; I suppose about 20 years ago. I recall he looked flushed and was complaining about the heat.

Webb had been a long time rotorcraft engineer, having worked for Kellett during the development of their syncopters.

[gyroplanes]

Thanks for the clarification Chuck.
When you have time you'll have to tell us about the "B" in Ernie's WPB "compound" and how about the Umbaugh in the Florida sink hole, or the tip jet helicopter in the used car lot.

I recall hearing of a Mcculloch J-2 in a used car lot in Minnesota (but that's all I remember of that story)

[Mike G]

Going from a 23' to a 26' rotor is a 27% increase in disc area, that plus a little head wind, a powerful pre rotator and a good pilot taking off behind the power curve all makes this a potentially deceiving bit of film for those of us who are new to this and think these guys are breaking new ground.
Thanks Chuck and others for the insight into how this was done.

Mike G

[Brad_King]

Actually, they put the 26' rotors on just for SnF. A 23 gal seat tank was custom built for a long range PR stunt.

The setup in the video had the 23' rotor and the really strong prerotator spun the rotor up til the mains started bouncing. The prerotator was released and the prop went to flight pitch and as Chuck said it jumped up behind the power curve and it was up to the pilot to take it from there.

Not sure where they will go from here. The new rotor is somewhere in the neighborhood of 30' with a 8" or 8.5" chord with the big tip weights. Way too much rotor for the modified Monarch.

But, what ever they put it on the rotor will be like the prop. 2 settings flat pitch and flight pitch. Then, we will see some true jump takeoffs and speaking from experience those can get real interesting.

Brad King
N6372K
Mad Max II LTC

[Robert G. Stark]

To say Carter Copter back in the air is misleading. This aircraft is not the origional Carter Copter. That aircraft accomplished its goals before it was destroyed. Jay Carter did a brilliant design and set new records. Now he is working to use some of what they learned for apratical aircraft.

[Hognose]

Bob, you're correct that this is not the original Carter Copter Technology Demonstrator. That is substantially damaged and is being preserved for possible future restoration for a museum.

Carter Aviation Technologies has two projects in the works now. One is to continue to develop (and market) its technology, and they are using the CarterGyro Demonstrator/Trainer, a modified Monarch, for that. The other is the 2+2 Personal Air Vehicle which is also a demonstrator, of which they plan to build three. The PAV will more closely resemble the original CCTD, but it will be smaller and lighter, and lower powered (the three models will have three different aero engines -- thank God, no more automotive derived problems. First one up will have a Rotax 914). When I say smaller and lighter, that's in reference to the CCTD, we're still talking about a big gyro.

They are working on a 45' rotor for a larger version of it, initial rotor is 34'. BIG Gyro.

cheers

-=K=-

[Robert G. Stark]

Sounds good to me.