SAB Goblin based mechanics

When we first saw a Goblin being flown by Bert Kamerrer at Daytona in 2012, I thought it was an interesting helicopter, but when he took the canopy off to change the batteries, we immediately saw the potential for the mechanics to sit inside a scale helicopters doghouse and be completely invisible through any side openings. cartier replica sale The problem was that the output drive, being a belt drive, was too high to go directly to the tail rotor. Over the next 12 months I developed a system which allowed the drive to be dropped down lower, and while I was doing this design we decided we would optimize it for as many different combinations as we could. hublot replica So now the drive height is completely variable, and can be for a belt drive or a shaft drive.

By making the side plates clamp onto the Goblin chassis, the whole assembly is completely rigid, and these side plates can be cut down and made shorter as they have been designed with a deep recess. cheap replica watches The horizontal bearing plates can be placed in any or all of the slots in the side plates. As long as one is at the bottom, the whole assembly is totally rigid.

By changing the Kv the rating of the motor and the pinion a large number of different head speeds can be accommodated, and by changing the final drive pulley, the tail rotor speed can be increased if required. We have supplied an 18 tooth pinion which will give the lowest head speed, but we have many options on different pinions both for 5 mm and 8mm motor shafts, and you can of course, change the KV of the motor to get the head speed that you want.

We can supply the complete system including the goblin mechanics or we can supply just the drop down gearbox system as you desire. If you buy the complete system then you will need to specify a main shaft length, and also purchase a swash plate, locking collar, swash lock, and rotor head parts. rolex replica If you specify the torque tube option, then you will need to decide the type of coupling you need from our mechanics. The output shaft is a 6 mm diameter shaft.

Will it fit? Here are dimensioned pictures so you can check so see if it will fit in your fuselage. I have them in a 600 size EC145 which has a wide doghouse. rolex replica uk It will not fit a 700 size Long Ranger which has a narrower doghouse so check carefully before you order. If you need to lower the mechanics in the fuselage to clear the motor or servos, we make a raise up gearbox adapter as well. This protudes 40mm below the bottom of the chassis and 70mm above the BOTTOM of the chassis.

Calculations!

To help you decide which motor and battery combination you need for your application, here are the gear reduction ratios to the rotor head from the motor

H0015-16-S 16T pinion = ratio 13:1

H0015-18-S 18T pinion = ratio 11.9:1

H0015-19-S 19T pinion = ratio 11.3:1

H0015-20-S 20T pinion = ratio 10.7:1

H0015-21-S 21T pinion = ratio 10.2:1

H0015-22-S 22T pinion = ratio 9.7:1

H0015-23-S 23T pinion = ratio 9.3:1

H0015-24-S 24T pinion = ratio 8.9:1

H0015-26-S 26T pinion = ratio 8.2:1

The tail drive pulley is sped up by 3.58:1 (68:19)

The SAB supplied tail drive pulley is now upgraded to 37 teeth. We supply a 26 tooth pulley which will give a tail rotor shaft speed of 5.08:1 over head speed.

If you bought a Goblin kit, it normally comes with a 27 tooth tail pulley so you will need a 26 tooth one.

At a head speed of 1200 the tail rotor shaft will turn at 6106 rpm. You can reduce this on a belt drive system by fitting the larger 27 tooth input pulley to the vertical shaft, a smaller output pulley and a larger pulley on the tail rotor gearbox. Reverse all that to increase the tail speed. To increase it for shaft drive via the two gears we can supply, you can fit a 24 or 25 or 26 tooth pulley on the drop down shaft but the belt will need to changed to suit.

We will only supply the 27 tooth pulley and the correct belt.

To help you decide what to buy if you want to change pulleys and belts, here is a list of options

First pulley size, then belt length closest loose fit and then closest tight fit.

27 tooth pulley 387 is loose 386 tight

25 tooth pulley 384 is loose 383 tight

24 tooth pulley 382 is loose 381 tight

Tolerances can probably be taken out by moving the side rails back or forwards in the slots, but you will have to drill out the mounting holes in the middle bearing holder to allow that to move also. Your choice.

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