recent change: 2016-02-24
This kit was designed for the skilled modeller. The manual contains more than 150 pages including 400 images. It can be downloaded for free! Take Your time and have a close look into this booklet so You will be able to reliably decide if You will be able to master this extraordinary rc model. Although the model´s structure can be managed in only a few days due to the perfect fit of its parts, finishing the aircraft will need a certain amount of steadiness anyway. In the end the pride of what You reached and the easy flying of the machine will make You really happy!

In order to shorten the time-consuming work of sheeting
3D-designed CNC-milled sheeting elements for fuselage and cowlings
are available for the Comet.

The aileron servos are located in frames that can be dismantled, e. g. to replace  a faulty servo.

Filling pieces are provided at the wing´s side for fixing the hinges.

For safety reasons the fibre glass control horns are connected with the frontal (balsa) part of the rudder at its full sectional area.

At RC-Network You will find a thread illustrating the (hi)story of the prototype (nickname: chris-67).

The thin tip bows are still designed robust. With a sanding block their levelling towards the trailing edge is to be worked out.

All spar boxes are realized as "comb spar boxes", i. e. comparable to a comb the spar box element is plugged into the wing along the spar crossing up to a dozen spars at once. This results in a significant time saving.

The motor- and gear cowlings´ load-bearing formers and frames are simply plugged in prepared ribs channels after the aircraft middle section was taken from the mounting frame. Distortions are hardly possible.

The two plastic straws close to the leading edge contain 2.5 mm2 high power cables. The remaining tubes contain the conductors to speed controllers (drive and gear), gear power supply, limit switches, ailerons and wing position lights.

Seven screws keep the integral main landing gear device in place, so installation or removal is possible within minutes.

Screw jack drive and electronical speed controller can still be applied quite easily through the opening. By dispensing with a removable fibreglass cowling much weight could be saved.

The landing gear and a microcontroller can be puchsed in the SHOP (Set H), auxiliary frames for grinding and hard-soldering included!

Pine spars are used as the wings´ leading edges, their frontal edges being a bit broken before sheeting.

The wing lock is done by a plywood pin held in a corresponding box by a nylon screw.

The two contacting wing ribs are provided with milled cut-outs so that standard plugs/sockets can easiliy be installed in their related plastic adaptors (Set E).

The prototype under construction.

The nose was cutted off the fuselage past the balsa sheeting.

Two doubled and boxed spar pairs run across the large aircraft midsection guaranteeing the demanded stability and strength of the wing construction. They furthermore follow two plywood formers, which are in turn resinned to the plug-in mounts (Strongal/Fa. Petrausch, Set D).

It hardly goes stronger and lighter at the same time!

The flap servos can be either moved and mounted through the flaps openings themselves or the canopy´s opening. The rudder crosses or disks can still be fixed to the mounted servo drives through the flaps openings.

Unlike the Comet original from 1934 that came with a dragged skid the glattCAD model got a simple wheel for reason of a better practicality. Its final design is left to the modeller, depending on his/her intended scale level.

The steering is done by two steel wires. Fibreglass control horn, spring steel, wheel, adjusting collars und wires are included in Sets A and E.

The ducting of the bowden cables through the frames were determined by construction, so the tubes follow a perfect curve from the servo to the control horns. The friction in the tubes and the rudder backlashes are minimized.

A mounting frame for the servos is provided. There is space for up to four standard servos (e. g. 2x elevator, rudder, tail weel).

The glattCAD prototype got the shiny black finish of G-ACSP Black Magic with the golden decals.

Additionally an only 23 µm  thin EASYPLOT ® decal sheet complete by transfer film (Set F) can be purchased.
You can choose the identification of G-ACSS (red), G-ACSP (black) or G-ACSR (green).

On 24th of June 2012 the glattCAD DH-88 Comet had successfully completed her maiden flight. The model flies very neutral, without tendency to kern or changes of its in-flight attitude.
Further flight confirmed the machine´s perfect aerodynamic design. The Comet can be landed slowly at effectively acting flaps. This is amazing, with regard to the strongly tapered wing tips!

> Video of the second flight <-

The tube frame, canopy and cockpit tub are removable in one piece.

On the backside two small fibreglass pins grab into the fuselage.

To securely fix the canopy a bowden cable with 0.8 mm steel core grabs into a piece of balsa under the glare shield.

The cable´s tube ranges forward to the removable nose, from where the canopy can be "remote controlled". Here the bowden, angled by 90°, lies in a milled nut in the frame. Accidental slipping-out of the cable is preveted by the applied nose. No device of the canopy locking is externally visible.

In order to replicate the canopy´s typical tube frame its devices, milled from glassfibre boards, are resinated. This yields a stable framework, to be glued with a transparent canopy from VIVAK ®.

The glare shield in the cockpit, an area for the instruments panel and a cockpit tub are prepared for the further design. Balsa is used in a hard gradation.

Only five machines of the Comet were built. The red G-ACSS Grosvenor House is regularly presented on Shuttleworth Collection´s taxiway - and even flying! The black G-ACSP Black Magic is restored at great expense.

With the glattCAD model in 5th scale these harmonious lines had to be preserved by all means. The wing´s outline was not modified thus a geometrical twist had to be provided.

Span and fuselage length of the glattCAD Comet amount to 106", resp. 70". It is powered electrically best.

Following the complete revision of the prototype the take off weight of the model  - depending on the "scalefactor" - is about 7.3 to 8.0 kg.
In order to save weight with the redesign certain selected pine spars were changed by balsa ones.

Both the original as well as the Comet model are almost entirely built of wood. The glattCAD prototype made its successful maiden flight on 24th of June 2012.

Hence this model has no further fibreglass parts except the weel pants. The two brushless outrunners (Ø 50 mm/length 65 mm class, weight 400..450 gr, 250 - 300 rpm/V) can be mounted and demounted through the engine nacelles´ openings. It is fully sheeted with balsa.

The fuselage nose can be removed. It is secured by four guided pen magnets in turn adhering to four flat magnets. They are glued to four pieces of balsa (light yellow in the screenshot).

Together with the strong adhesive force of the rare earth magnets this linear conduction prevents the nose from bidding farewell on the fly.

The battery pack - fixed on an fibreglass carrier - is inserted into the fuselage from the front.

Of course it is recommended to install a powerful landing light to the glattCAD D. H. 88. Modern LED technology is best suited.

The prototype has been equipped with CREE MC-E emitters on "starplatine", being installed to a suitable Fraen reflector (beam angle 32°). The power is more than 10W.
The lighting is not included in the Comet Sets.

De Havilland DH-88 Comet

Especially constructed for the MacRobertson Air Race in 1934 this airplane enjoys a cult status among us modellers. Her smooth outlines still convince, 80 years old, as if the designer had created them only yesterday.
You can order the milled short kit here in the SHOP!

-> Full Manual (German) <-

As can be seen in one of the pictures above, fuselage, vertical fin, elevators and all rudders are built up on special mounting frames. This procedure guarantees a twist-free construction.

For weight reasons the spars in the fuselage, wings and tail are partly made of pine or balsa, depending on the load. The thin balsa spars assure precise gradients of the sheeting whereas strength and stiffness are provided by the pine spars.

The battery slot is delicate and of high strength at the same time.  It allows the fibre carrier to be locked in different defined positions. For this pupose small holes were milled centrally. This concept offers the inestimable advantage of being able to adjust the center of gravity precisely at any time easily.

In the front, beneath the slot, batteries for reciever and landing gear can be stored. A small platform was provided especially for this purpose.

Further back in the battery slot a slidable abutment can be seen. The removable vertical pin in the middle allows to displace the abutment.

5.5 mm gold contacts are glued into it. While the carrier being inserted into the slot they automatically make both an electrical connection and a safe mechanical fixation. Additionally the battery is secured from falling out in the front.

The cad screenshot to the right shows the battery carrier abutment with the 5.5 mm contacts and an aluminium locking pin from a different perspective.

Unintentional rotation of the abutment is prevented by constructive means: A pine rod is running loose in a related channel but enabling the abutment to slide fore- and backward. It can be reached through the canopy opening.

Each lead or cable to be conducted over a longer distance in the model is embedded in a thin-walled tube. For this puropse "sangria" drinking straws are used. The part positions where the straws are to be glued had constructively been prepared.

At the rear a high-power led can be installed (e. g. Seoul emitter, 3.5 W) as a position light. Because of the high junction temperatures these electronical items must be connected to a heatsink using thermal adhesive. Typically they are bar-shaped aluminium at a diameter of 8 mm.
The frames are prepared for installation. The leds and heatsinks are not part of one of the Sets offered in the SHOP.

Another "sangria straw" through the frames is provided for ducting the related pair of conductors.

Rudder, elevator and ailerons move in channels.

They are controlled by the using classical pin hinges (part of Set E). All rudder horns are milled from glassfibre boards. They are fully integrated and glued to the frontal balsa area in the rudders thus obtaining a reliable steering.

The elevator unit is built up on a mounting frame in one piece. It is installed in an intricate construction to the fuselage without any chance for mounting failure. The rudder and all ruder blades are prepared on mounting frames and the upper side is even sheeted there.

All mounting frames can be taken from the build table (nearly) at any time and be reinstalled without the fear of distortion!