Low cost jump takeoff vehicle

[Dave Jackson]

http://www.synchrolite.com/JumpTakeoff2.gif :D

[ 05 November 2001: Message edited by: Dave Jackson ]

[baranfin]

I had one when i was younger, it was too hard to learn without the stability augmentation device or dual controls :p

[Capn Notarious]

I understand that they are VFR type rated.
VERY FIRM RIDE! :D

[Lu Zuckerman]

To: Dave Jackson

It is my understanding that in the process of going up and down and the operator exceeds 18-degrees from the vertical he will fall over.

[Capn Notarious]

Are but due to Gyroscopic precession, if he makes input changes 90 degrees earlier will that prevent such a failure.
Best not to discuss Hookes Joint effect, as it alludes to smoking an alternative product. :D

[The Nr Fairy]

Lu :

That's actually funny !!

[rotorque]

Use to operate an 'F' model, not a bad machine but no matter how hard I milked it I couldn't get it out of ground effect.

[Lu Zuckerman]

To: Capain Notarious

In order for gyroscopic forces to come into play there must be some level of rotation. It would be difficult for the operator to maintain any degree of rotation without mechanical help. If he had a set of deployable weights attached to the control arms he could establish the rotation and then while he is doing that he could deploy the weights adding momentum. Once he had established his initial rotational speed he could retract the weights (ice skater analogy) thus increasing his speed to the point of establishing gyroscopic rigidity maintaining a vertical attitude at all times.

There are several problems. If the operator shifts his weight or leans in any direction he will encounter gyroscopic precession forcing him into an unusual attitude, which will further perturb the gyro effect and cause him to nutate and end up rotating in a conical pattern. Another problem is dizziness from the constant rotation but this can be overcome by practice much like the figure skaters. There is another problem of a mechanical nature but it is solvable. If you note on the technical view of the craft you will notice that the bottom of the shaft there is a crutch tip which provides both friction and a minor amount of shock absorbing. It is the friction that causes the problem. Because of the high frictional coefficient of the crutch tip the bottom shaft will be constantly reacting high cyclical torsional loading. This could eventually result in a torsional fracture of the shaft causing the craft to fall and the likelihood of serious injury to the operator. I mentioned that this condition is solvable by the inclusion of an isolating bearing that has a low frictional coefficient and is capable of absorbing repetitive axial loading.

I believe with this configuration and sufficient operator training the craft may gain certification. However the certification authority and most likely the manufacturer will require that the operator attend a safety course.

[Cyclic Hotline]

This vehicle is easily controlled and suffers from no inherent design flaws!

I have considerable time on these and can recommend them without hesitation.


This picture is of the well known "Blue Angels" performing at an airshow! :)
http://www.volunteeringireland.com/Images/Photos/102-0204_IMG.jpg

[Lu Zuckerman]

To: Cyclic Hotline

It is true that these devices are operationally simple and can be operated by untrained individuals. The basic design is inherently reliable but that reliability is totally dependent upon the surfaces that the device is operated on. This limits its’ operational deployment. Although it is an extremely simple device it will require a high degree of inspection to assure the operational condition of the lower surfaces of the device. This high level of maintenance will equate to high operational expenses, which will negatively influence any high volume civil or military acquisition programs.

One means of preventing deterioration of the lower surface is to install a device similar to the skid shoes used on Bell Helicopters. The increase in reliability might be offset by the increase of the Mean Up Weight of the device as well as increasing its acquisition and operational costs because of the increased spares requirement.

:rolleyes:

[ 06 November 2001: Message edited by: Lu Zuckerman ]

[Capn Notarious]

As has been demonstrated in many a slow motion film: it is the cat; that from any angle will descend and land on all fours, due to its inbuilt gyros. Thus Lu can therefore be the only one suitably trained to command as P1, in such a vehicle. We await the visual evidence, displayed here.
Now to reflect on the subject of spinning: ask ROOFUS! :D

[Lu Zuckerman]

To: The Captain

At age 70 soon to be 71 I have difficulty in walking up and down the stairs. I don't fancy myself hopping or bouncing up and down.

But thanks for considering me as P1.

I could possibly perform the R&M analysis and / or act as service engineer.

[Lu Zuckerman]

To: Helidrvr

The spherical air vehicle presents a constant sail area no matter which way it moves and the aerodynamics are constant thus it can move in any direction and still be in trim. This does not take into consideration the cross section of the operator, which may perturb the aerodynamics of the vehicle. If the vehicle can be operated autonomously such as a UAV there would be no problem however the vehicle requires some type of energy source to make it operational. To maintain the aerodynamic characteristics that energy source must be mounted inside of the vehicle. If the vehicle can be made large enough the operator can also be contained inside of the vehicle.

The other vehicle constitutes a major problem. Even though it is spinning the cross section of the operator is constantly changing which in turn alters the aerodynamic characteristics of the vehicle. This can be countered by containing the operator in a cylindrical housing with a constant diameter. This too leads to another problem. As the vehicle passes through the air it generates vortices. The shedding of these vortices can lead to aerodynamic instability resulting in high lateral side forces that alternate from left to right. This vibratory level coupled with the high spin rate might result in G LOC resulting in the crashing of the vehicle.

In summary, the spherical vehicle can be made to perform any aerodynamic maneuver to include sideslip and out of trim flight. Actually, due to its’ shape out of trim does not come into play. The other cylindrical vehicle has major design problems that require significant engineering effort to make it fully operational.
:rolleyes:

[Cyclic Hotline]

I have no time on these, so cannot vouch for their safety.

Common sense would dictate a very reticent use of this device - but when did that ever influence anyone? ;)
http://totallyabsurd.com/pogoshoes.htm

But these. Now they look pretty cool to me;
http://www.kenguru.de/Bilder/Powerskip_pics/powersk ip_pics.html (http://www.kenguru.de/Bilder/Powerskip_pics/powerskip_pics.html)

But then, this is what I do for a living!
http://www.bestoffrederick.com/colebros/cannon.jpg
Well, I work at a Circus anyway. :)

[ 07 November 2001: Message edited by: Cyclic Hotline ]

[Capn Notarious]

One idea comes to my mind. Dissymmetry of lift. Now consider this one rotorheads: if the well paid pilot of this machine; has a heavy wallet in one trouser pocket. Would all the corrective ideas of Lu come to no avail :D

[Lu Zuckerman]

To: The Capn

“One idea comes to my mind. Dissymmetry of lift. Now consider this one rotorheads: if the well paid pilot of this machine; has a heavy wallet in one trouser pocket. Would all the corrective ideas of Lu come to no avail”.

This condition could never manifest itself. You prove it in your own words. “well paid pilot of this machine; has a heavy wallet”. How many pilots in this industry are well paid and have a heavy wallet?

[ 08 November 2001: Message edited by: Lu Zuckerman ]