Archive

Archive for the ‘Modifications’ Category

GForce Upgrade – Aurora Metal Tail Grips

April 7th, 2010 3 comments

GForce LogoThe other weekend I had one of the plastic tail grips fail on my Avant Aurora, which is essentially the first flight failure I’ve had with the Aurora. The arm on the tail blade grip which holds the ball fatigued, cracked and the ball pulled out. Fortunately I was able to get the heli down with minimal damage.

(broken plastic tail grip)
aurora-broken-grip

Needless to say I’m now looking for a metal tail grip solution to replace the stock Avant plastic ones (which perform fine… they are just not durable enough IMHO). After digging around it turns out GForce maybe able to offer a solution if there is enough demand for an initial run of replacement grips. Hence a show of hand is required to get and indication of how many people would be seriously interested in a set. (yes I know Avant have some in the pipe line, but there is no indication of when that will be)

If you are interested in a set of quality metal tail grips specifically designed for the Avant Aurora please contact Garf at GForce to express your interest, his email can be found in the following thread on RunRyder: http://rc.runryder.com/helicopter/t579394p1/

 
 
 

Trex 500 Canopy Mount Modification

November 6th, 2009 No comments

Trex500 – Standoff Mod – Side2During the recent build of my newly acquired Trex 500, there was one small concern that jump out at me and that was the rear canopy standoff’s…and how shit they are (that aside the Trex 500 is great quality and value). And it’s not just because the canopy mounts are plastic, as plastic mounts will often save your frame in a crash. The issue is the canopy mounts don’t seem to sit far enough in the canopy lug holes and/or with enough tension for my liking (I normally upgrade the canopy mounts to “thumb-screw mounts”). Also there have been a few reports of Trex 500’s loosing canopies in-flight, either way something needed to be done and there are no thumb-screw upgrades currently available.

It turns out you can fit a pair of Trex 700 canopy mounts with a small amount of modification and as luck would have it, I had some lying around as I upgraded my 700 mounts to QuickUK thumb-screw mounts.

The main modification is to the plastic swash guide, the main frame is essentially untouched. One concern with the modification is in a crash the metal mounts will transfer more energy to the frame (rather than bending/snapping like the plastic counterpart), my solution to this was to cut 2 small sections of carbon fiber and bolt them to the frame using existing frame holes. This effectively doubles the frame width around the canopy mount point and hence reinforces the frame.

The Modification

The Trex 700 standoffs uses M3 bolts (into steel) and the Trex 500 uses M2.5 bolts (self tapping into plastic). So you will need to enlarge the canopy standoff holes in the frame just enough to accommodate an M3 bolt, which should easily be done in a few seconds by rubbing a small drill bit inside the canopy standoff holes.

The swash-guide also needs its bolt holes enlarged enough to accommodate a M3 bolt (you need to source 2x M3 bolts), note that the M3 bolt will not be tapping and held by the plastic (although it will be a tight fit). The trick with this is there is not a huge amount of meat on the plastic so you need to drill very straight and not make the hole to large. That said, if you make the holes too small the plastic will crack when you push/screw the M3 bolt through. When you have drilled through to the end you will notice the center support pin start to fall away…which is fine cause we don’t want it any way :) Finally cut away any protruding plastic in order to allow the M3 bolt head to sit snug against the inside of the plastic bolt hole. Bottom line is if you stuff up the plastic swash-guide modification it’s only a couple of £ to replace. I brought a spare, however I manage to get the modification right the first time. Installing the swash-guide and bolts back into the frame is simple, a ball-end hex driver is a requirement though.

Frame bracing around the bolt hole is optional but recommended and if you’re like me you probably have an old broken frame you can use for carbon. I wont go into detail you just need to cut some carbon to match the frame around the bolt hole (see below) and drill some holes in the brace to match the location of the rear bearing bock bolt hole and canopy mount hole. You will need to also source 2 slightly longer M3 bolts, that’s it.

Installed Trex 700 Canopy mounts on Trex 500

Trex500 - Standoff Mod - Back

M3 bolt snug against modified swash-guide (need ball-end hex to gain access)

Trex500 – Standoff Mod – Side3

Installed carbon brace for canopy mount/standoff

Trex500 – Standoff Mod – Side

Trex 600 6s-8s Scorpion 890KV Modification

October 14th, 2009 3 comments

Scorpion HK-4025 890kv - BoxI recently burnt out my Align 650L 1220KV motor on my Trex 600 and decided it was time for an upgrade (as a side note the 650L was a pretty good motor as far as Align goes it lasted over a year). One of my main goals was to allow me to initially continue to use my current configuration of 6s batteries and 100A Align speed controller. But at the same time allowing myself an upgrade path to an 8s setup once my current set of 6s batteries die (that also implies an upgrade to a high voltage speed controller).

 

Scorpion HK4025-890KVScorpion HK-4025 890kv

I finally decided on a motor, the Scorpion HK4025-890KV, which actually comes in slightly cheaper and lighter than a replacement 650L 1220KV with similar power consumption. The one main difference however is the KV rating, a difference if 330KV. The way to compensate for the lower KV was to use a larger pinion, as it turns out Mikado do a 20t pinion which fits a 5mm output shaft, which addresses the problem nicely (on the 650L 1220KV I was using a 15t pinion)

Mikado 20t Pinion

The Scorpion motor whilst shorter in length than the Align 650L is slightly wider, and the 650L was a very tight fit, hence a simple frame modification is required to get this badboy in. A small section of carbon just below the motor mount needs to be removed on both sides of the frame, nothing a couple of minutes of dremeling wont fix :)

Before Frame modificationTrex 600 Frame Mod

After Frame modificationTrex 600 Frame Mod

Once the frame has been modified the motor slides sideways into the frame easily, the next thing you will notice is the Mikado 20t pinion is so big it doesn’t clear the main gear (and if you took the main gear off it’s likely to be too tight or not fit at all).
Another small modification is needed, this time to the Align motor mount, again very simple, all that is required is the bolt holes need to be enlarged lengthwise towards the front of the model which can be done with a drill and 4mm bit. You don’t need much, I drilled one hole at the end of each bolt hole to enlarge it, which allows the motor to slide forward more on the mounting bolts.

Align motor mount after modificationTrex 600 Motor Mount Modification

Installed Mikado 20t pinion and modified Align motor mountMikado 20t Pinion Installed

All things considered this modification was very easy and other than the Mikado 20t pinion no other non Align parts are required. No one likes modifying frames but this was truely very quick and simple with the dremel and doesn’t compromise the frame at all in my opinion. Also as it turns out I came up 70g lighter which is always a bonus.

Scorpion 890kv Modification Complete

Flight testing on 6s with the Align 100A speed controller went very well, I don’t think I’ve gained or lost any flight time I’m still at 4mins hard 3D. The motor seems have good torque and be very resilient to bogging, the ESC and motor temperatures are also healthy. Overall performance with my setup is slightly above the 650L (…and I had good results with the 650L). Obviously with any 6s setup when flown aggressively will push the batteries limits in terms of heat, current draw and performance which is why in the future I will be moving towards 8s, which the Scorpion HK-4025 890kv should handle nicely.

DX7 Gimbal Stick Upgrade

August 31st, 2009 No comments

JRPA143 Gimbal Stickends (DSX12)Whilst there is nothing specifically wrong with the standard DX7 gimbal sticks, they are not as sharp as I would like them, particulary after some use. I had a look around online and found some DSX12 Standard length Stick Ends (JRPA143), which are in fact the same length as the standard DX7 sticks. They were also recommended as being a stick upgrade specifically for the DX7.

I just got around to screwing the new stickends on (DX7 is not my primary radio now) and found a little bit of a problem, they don’t screw all the way down on the gimbal thread (the standard DX7 sticks do) so you end up with a stick 7mm longer than planned. Which for me is a problem as I  like my sticks ends short.

The JR sticks do come with a replacement gimbal sticks, which should be tension fitted in the plastic gimbal which is not something I really want to attempt because before you can put them in you have to “bash” the old ones out of the DX7.

The new JR stick ends are threaded from one end to the other, unlike the DX7 sticks which are thread 3/4 of the way from the top down, which allows the stick to be wound all the way down. The solution is to get a 4mm drill bit and drill approximarely 7mm out of the bottom of the stick end which will remove the thread that prevents the stick end being wound all the way down. After drilling use a M4 screw and screw from the top down to ensure the start of the remaining thread is clean, this will also help avoid cross threading. When screwing the modified stick ends on make sure there are no loose thread shavings as they will get stuck in the gimbal which is a pain.

JR stick end with new gimbal shaft inserted (this gimbal shaft was not used)

JRPA143 (DSX12 Stickend)

DX7 with new JR Stick ends

DX7 with JRPA143 (DSX12 Stick-ends)

All things considered they are great quality stick-ends and after modification they are perfect. I wouldn’t however market them as DX7 compatible unless you don’t mind really long sticks or modifying your DX7. Had I known I had to modify them first I probably wouldn’t have purchased them.

3D Retractable Landing Gear

August 5th, 2009 2 comments

Very cool idea, retracting the landing gear (this could be easily hooked up to the flight mode switch) would improve the COG, but is it worth the extra weight? Either way 10 points for style :)