Written by Ashley Davis Friday, 13 May 2005 00:00
The following is a review of the Heliup Tail Gear Case and Tail Pitch Slider.
Initially let's take a look at the tail gear case....
The tail gear case is a beautifully made piece of equipment and as anyone can see from the pictures it is truly at the top of it's class when it comes to bling factor. The question is why would you want to put this onto your T-Rex in the first place? There are several elements to this design that are attractive. Firstly it is an open case design, which means maintenance is easy and wear on gears and the tail belt can easily be identified. It also does not act as a dirt trap as there is nowhere for the dirt to settle and cause wear on your moving components and bearings. The case uses a clamping system using 2mm allen bolts to secure itself onto the tail boom. This is extremely effective and the whole system feels like it is welded to the tail boom once tightened up. This avoids problems of the gearbox twisting in flight which I have now seen on several T-Rex due to the difficulties of tightening up the stock case that uses screws into plastic (which can strip very easily). The last and by far the most significant reason for getting this case is that it provides a rock solid mounting platform for the heliup tail pitch slider. Initially I was going to review the tail gear case and tail pitch slider separately but it is very evident that these two upgrades are designed to work together. The bottom right picture above shows the mounting platform for the tail pitch control horn.
So, onto the second part of this review, the tail pitch slider ....
The tail pitch slider is designed around a cup and ball type approach with the normal ball link screwing onto the control horn at the opposite end to the plastic cup. The servo control rod attaches to this ball as per the stock slider. On the supplied slider the ball was extremely tight in the cup. I had to spend a little time with some fine grain sand paper just taking the edges off of the plastic in the cup to make the ball a much smoother fit. This was really very easy and not a difficult problem to resolve. The slider uses the balls and ball links from the stock pitch slider control horn, this is just a straight forward swap over. The bearings in the slider are of sufficient quality for the job they are required to do and are of a higher quality than those in the stock slider.
So let's have a look at the build up of these components ......
Once built up the advantages of having both the CNC slider and CNC tail case are evident. The control system from control horn to pitch slider is not only very smooth it is totally without slop of any kind. This is the advantage of mounting the control horn onto another CNC part. If mounted onto plastic it would not be as tight tolerance and some slop would creep back into the system. The only area where some unwanted movement can occur is on the rotating ball links screwed onto the slider itself. This can be mostly eliminated in making sure that the links are tightened down as far as possible without causing any binding or obstruction to their ability to rotate.
So having completed the build on to flight testing.
It has been a considerable time since I have had any issues with tail wag. Using a good gyro (in my case the CSM SL420) and a fast servo (HS50) I have not seen any tail wag despite various changes to the tail control system. The Heliup system certainly didn't introduce any wagging and if anything I was able to eek out a tiny bit more gain on the gyro before inducing some tail wag from having too much gain. The CSM gyro was up around 85% gain so I wouldn't have wanted anymore than this. Some small adjustment of the tail control rod was required to get good steady tail control without using heading hold. This is to expected with the size of change made to the tail control system. Switching to heading hold the tail locked on immediately and the benefit of that rock solid control system could be felt in the tail response. This is using the standard tail which has some slop in the tail grips. I should be able to remove the final elements of slop when I install he MicroHeli unit which still has some testing required. This should produce a very finely tuned tail system for anyone keen on upgrades to the tail end of their T-Rex.
Overall I very much like this upgrade, apart from having to sand the cup on the tail pitch slider very slightly it all went together without any hitches or problems. There is no binding in the system and the whole unit operates together extremely well. If I was to pick an upgrade to use for the tail system then based on the reviews done so far I would pick the Heliup combination. Having said that there are at least two other contenders in this particular upgrade area. It will be interesting in future weeks to see how these compare. For now Heliup has the top spot.
Just for the weight sensitive people this upgrade doesn't offer any weight advantages over the stock system.
For the image conscious, it should get the odd 'ooh and ahhh' from bystanders and fellow fliers.
For the financally sensitive this upgrade is more aimed at the experienced flier than the beginner. However it is unlikely in a mishap that any of these components would get damaged. The tail sits out and away from the components that most often get bent or broken. The plastic blades and blade grips will break long before these CNC parts take damage, so it should last through the majority of mistreatment.
According to the US Distributor (www.RCHover.com) this part will be available from 16/5 as well as the Heliup Carbon Fibre Frame.
For anybody looking to really fine tune their tail system I would recommend taking a look at this combined system.
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