Jump Jet FAQs

Q What is Jump Jet?

A Jump Jet is a vertical take-off, hovering aircraft which uses a combination of 3-axis solid-state gyro sensors and special aerodynamics to produce stable yet highly manoeuvrable flight. It is optimised for a living room environment, where we believe that many hobbyists would like to be able to fly. So it is lightweight, durable and it has no whirling rotor blades to take out the knick-knacks on the mantelpiece. It can fly forwards and steer like an aeroplane, but its speed is self-governed to a rate suitable for a domestic space. Of course it can hover about like a helicopter, and can be landed on the palm of an outstretched hand. It can also be flown all around the house!

Q Is Jump Jet suitable for learning to fly?

A Definitely yes. Unlike a radio controlled helicopter, Jump Jet is aerodynamically self-righting, which means that it tends to bring itself back to a horizontal, stationary hover if it is tilted or moving. This makes it a lot easier for a new pilot to get it into the air and begin developing a feel for it. However, unlike many "super stable" hovering novelty products, Jump Jet has a full set of effective flight controls, so it can be flown with similar precision to a true RC helicopter. Additionally, it is very safe to operate, with no large whirling rotor blades.

Q Does Jump Jet have proportional controls?

A Yes. It has four, fully proportional channels of control.

Q Are spares available?

A Four spare props are included with every Jump Jet. We stock propellers and other spares, the range of which will increase as further parts become available.

Q: Can several batteries be used so that the Jump Jet can be flown more than once without re-charging?

A: We offer spare batteries as replacements for worn-out units. Use of multiple batteries is not recommended because the Jump Jet's battery socket is not designed for frequent re-connection. Additionally, back-to-back flights will cause excessive wear of the motors, because they will not have the usual time in which to cool down.

Q What is the benefit of infrared control?

A Infrared control has one huge advantage over radio-based communication: It works by line-of-sight, so it cannot suffer interference originating from outside the immediate environment. Jump Jet is intended to be operated indoors in a confined space, amongst people of all ages. It is therefore crucial that it doesn’t pick up interference from another nearby transmitter, potentially causing erratic or violent movements. Infrared control is immune to interference coming from outside the room it is operating in.

Q Can the Jump Jet be trimmed?

A The Jump Jet has no trims on the handset. That’s because the electrical values of both the TX signal and the on-board gyros are automatically zeroed at the aircraft each time the TX is switched on. If the handset had trims and these were offset from centre, the aircraft would re-zero to these trim positions at the next power-up, negating their effect.

However, the automatic trim is not always 100% perfect because it cannot correct for small differences in performance between the motors and propellers, or a centre-of-gravity imbalance. The best way to correct these errors is by adding one or two small blobs of Blu Tack to the extremities of the aircraft as necessary to bring it into balance.

Q Can Jump Jet be enhanced in any way?

A Performance can be "souped-up" considerably compared with the stock product, by removing unnecessary weight. In order to qualify for mass-marketing, Jump Jet includes a number of parts whose purpose is to make the aircraft pass various stringent safety tests, which go way beyond the requirements of hobby aircraft. A typical model helicopter is after all, a self-assembled, flying power scythe, with hot parts, noxious fumes etc. It is up to the operator to use it safely.

If you are such a responsible hobbyist then there is no reason not to pare down your Jump Jet to obtain the best possible performance…the performance it was always meant to have! But do treat it with respect.

These two measures will save a total of 7g – more than 10% of the aircraft’s weight! Climb-out speed will be greatly increased, and up to a minute may be added to the flight time. One note of caution: At its stock weight, the aircraft is designed to have insufficient lift to fly when nearing the end of the battery’s discharge, so that it is safely landed before the power cut-off point is reached. With reduced weight there is a good chance that it will still be airborne when the power quits, so be careful!

Experienced pilots might like to consider flying with the foam body removed altogether. The four-rotor "flight engine" is perfectly flyable by itself, and is very fast and manoeuvrable. It will no longer be self-righting however, so take care! RC helicopter pilots should have no trouble flying it. It would be a good idea to re-fit the propeller guard rings, and to add a conspicuous marker to indicate the aircraft’s orientation.

Q Why do all the propellers turn in the same direction, instead of in counter-rotating pairs?

A Jump Jet belongs to a class of aircraft known as "quadrotors", and traditionally these have used four horizontal propellers with diagonal pairs turning in opposite directions. On such a machine there is no net torque reaction, and yaw forces have to be generated entirely by differential torques from changing the propeller speeds. Jump Jet has small, direct drive propellers which do not generate much torque reaction, and the aircraft has the outboard foam body which has a large moment of yaw drag. As a result, differential torques alone are not enough to provide adequate yaw authority. To boost this, we could have tilted the counter rotating pairs of propellers equally in opposite directions, making a small portion of their thrust available for yaw control. However, having once decided to tilt the propellers, it was a small additional step to tilt the pairs by different amounts so that all the propellers could turn the same way. The resulting net torque reaction is compensated by the differential tilts.

The benefit of this is simplicity....only one propeller to make and no worries about which is which.

Q What is the control range?

A Infrared range varies depending upon the environment. Although IR works in straight lines (rather like a torch beam), it provides good omni-directional coverage of a room because it reflects and re-reflects from the walls and ceiling, filling the available space with energy travelling in all directions. A torch beam can illuminate a whole room in the same way.

However this only works well if the room is not too large, and the ceiling is not too high. Generally a domestic room with 8 – 10 foot white ceilings is ideal, when range will be 20 – 25 feet. This allows full freedom within the great majority of home spaces.

Range will be reduced outdoors or within a large indoor space such as a sports hall. Also, some types of lighting can disrupt IR reception and reduce range, especially high powered discharge lamps and some types of fluorescent tube. Domestic lighting usually causes no problems, unless the Jump Jet is flown very close to the lamps.

Q How can the IR control strength be maximized?

A The Jump Jet’s infrared control is very robust in most domestic environments. However in larger rooms and at longer ranges, it is necessary to keep in mind the transmission medium being used. The following tips can make a real difference:

3) Avoid direct sunlight, which will reduce range dramatically if it hits the aircraft.

4) Jump Jet will not tolerate other infrared devices operating in the same room.

5) Use fresh, alkaline batteries in the handset.

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