Build

All change.........again...........

Rebuild is underway (see the 'testing' page for the reason why) and the scale is now 1:9 with the AUW rising to 10lb (estimated). So now onto structure number 7 with 48 cells now powering the beast. Thats 3 packs of 16 x 1700mAh cells, matched and zapped. Pictures will follow, including scale home built landing gear.

There are loads of detailed pictures on this page so be patient while they load, its worth it!

OK...some of the kit thats going in the model, all the electronics are shown together with the Spring-Air retract units, the two rear motors and Shultz ESC's.

The next build picture shows how the two WeMoTec HW620 fans are joined together. You can also see the bearings on each side and the spur gear used for rotating the unit. Notice also the 2mm carbon fibre rod used to pin the bearing blocks into place. The left bearing block is a modified carbon/plastic RC car drive component, as is the right spur gear. The main shaft is 5mm solid carbon rod.

The body is started with two formers running down each side, the photo below shows the port former which also locates the HS-77BB servo used to rotate the rear fans. You can also just see the potentiometer from the servo which has been removed to allow the servo to rotate the correct number of turns for 90 degree rear fan rotation. You can also see the bearing seat, split to allow the rear fan assembly to be removed from the model. This part took a long time to setup as the location of the bearing face and servo gear is critical for smooth rotation of the rear fans. The 4 screws are locating the HS-77 to the former, one is inset as the rotation assembly gear sits there.

Hear is a mid-build of the rotation assembly, you can see the servo and the new location of the potentiometer which is linked to the rear fan assembly shaft. Also shown in this shot is an initial set-up of the speed brake assembly which is also driven from the rear fan assembly.

A view of the rear fans (the body is upsidedown, and the fans are shown at about 80 degrees from horizontal i.e. not quite hovering). Those linkages for the speed brakes were a nightmare to setup but once the geometry was sorted the speedbrakes moved very smoothly. I wanted them to be directly moved by the fan assembly as they will take quite a bit of loading if deployed at speed, got to slow the model down quickly right? its all scale. You can also just see the battery bay which allows the cells to be removed from the belly of the model.

Another view of the rotation assembly with the fans in 'conventional' mode, i.e. 'normal' flight.

A montage of the rear fans rotating from conventional flight to hover mode. Note the addition of linkages on the inside of the speed brakes, I really dont want them to fold when they are deployed.

A close up of the routing of the motor wires through the fan assembly. Also shows the inner speed brake linkages, and yes I know the nuts on the speed brakes are not tight. Its getting 'busy' in there and theres more to add to this area.

A view of the body, from below showing the formers (theres 22 in all) all hand cut in 1/8 balsa. You can clearly see the battery location which is infront of the speed brakes. The cells will be held in position by 'velcro' strips which feed through the slotted holes cut in the side of the battery bay.

The front end from above. The front lower section is sheeted with 1/16 balsa. You can see to location of the front fan clearly, and the efflux area.

A view of the back from above showing the rear formers in postion. The balsa strips are where the rear transition doors open to allow the jetpipe to rotate down. Also shown are the rear fan ducts which will be cut to allow rotation, made using an oak former and some plastic bottles which are heated to shrink around the former. The former is also used to make the front fan efflux duct, shown later.

The lower nose, sheeted in 1/16 balsa, 25g weight, the balsa was attached in 2 inch strips, each piece individually cut to fit, those curves were fun....