rchelicopterhub.com / rchelicopter.hu
16 January 2023

SAB Kraken is not for scale helicopters. Really?

"Hold my beer" Glen said, and he made it. And he repeated it not only once, instead, multiple times. If you think, the well designed and nice SAB Goblin helicopters cannot be converted to a scale helicopter, well: you are wrong, and Glen Scalemale provides the evidences.

An average scale RC helicopter pilot would think of anything else rather than SAB Goblin as a base for a scale helicopter. Obviously the best option is the fine scale mechanics, but they are so expensive, most of us willing to build a semi scale helicopter would consider something from the performance range, which can be fit into a scale fuselage. And the SAB helicopters would be the last in the line.

But before you get to this conclusion, maybe you want to contact Glen Scalemale from Brisbane in Australia. Glen has a different view about it, and there's a story behind. Glen is a fixed wing RC pilot, but as he said, he has always had a love for helicopters. This is why he has been building and flying scale helicopters for about ten years now. 

Around the time when the Roban 800 Airwolf was released, he could have one with original Roban mechanics from the early release. Glen was satisfied with it by his experience, then by the time passed, he has made more improvements and changes for a better reliability. As it's known building and flying scale helicopters require huge time and even more money, therefore reliability is one of the key aspects, if it's not the most important factor.

Initially Glen wasn't a fan of belt drive systems,  later on he found that the Kraken mechanics is very efficient as well as reliable, therefore he can achieve up to 10-15 minutes flying times, when the Kraken is coupled with his another favourite, the Kontronik power system. Finally this combination ended up as the "KrakenWolf".

The original SAB Goblin Kraken mechanics had to be modified, some of the front of the battery frames was removed to fit in the Airwolf fuselage.

I made custom carbon tail frames to stretch it to 800 size, and found another original Goblin belt to suit.

The original main shaft of Kraken wasn't good for this purpose either, therefore it has been replaced with a Synergy 766 main shaft which also had to be cut down, this way the Kraken has got a longer main shaft to suit this fuselage. 

Then there was the next big problem: The rotor on the Airwolf is rotating counter-clockwise, but Glen could manage to reverse the one-way bearing. Finally one major problem left: the tail rotor of the Airwolf is located on the left, consequently, the tail block had to be turned from the right to the left side. This created the necessity of modifying the whole tail servo mount, and this is why the tail servo mount is located over the boom.

Glen said:

The whole mechanics can be removed without too much work, and then flown as a typical pod and boom helicopter, albeit the stretched version.

"I have also done a similar conversion on the Roban Bell 429, which required a lot more engineering, including custom carbon side frames and custom tail shaft extender to lower the tail boom. Both the B429 and the Airwolf fit a full Kraken tail boom inside the fuselage."

Glen is planning to convert a Roban Bell 412 and a Fun-RC Bell 407 to SAB mechanics, just these projects obviously long-term plans, as neither his time nor his funding are unlimited.

If you think about a similar project, it's recommended to listen his opinion:

It does take some though end engineering to adapt the SAB mechanics, but to me they are ideal with their compact and modular design and very reliable, with ample spare parts available, so I would recommend this as an ideal platform for anyone to consider when building a custom scale helicopter.

Glen told that, if a scale cabin is planned, the SAB Goblin Kraken gearbox is helping a lot, as it allows more room for a full scale interior.

What about newer SAB models? He told that's not experienced yet, although it's very likely, the SAB Goblin Raw may make an even better option is particular applications.

SAB Kraken is not for scale helicopters. Really?