Century/Funkey .30 Jet Ranger & TRx550 build

[npomeroy]

This won't be too detailed step by step. My intention is to give details on components used, and modifications I made, and later hopefully flight data and electronics settings.

- Fun-Key .30 Jetranger and T550 (no electrics or blades) from century-rc.com in Hong Kong. 550 comes with flybar - replaced with Align 550 FBL head (not DFC)
- Align DS615 swash, DS650 tail, servos.
- Scorpion 4025 - 1100kv motor
- CC ICE 75 ESC
- Western Robotics Hercules Super Mini BEC
- SK720 FBL gyro
- Spinblades semi-symmetrical 550mm blades

Thanks to "Keyrigger" for initial suggestions for 550 mods. I will be replacing the main shaft with the longer (201mm) 600E shaft.

I intend to run low head speeds (below 2000), and opted for a 1100 kv motor (Stock 550 is 1220kv) which gives me additional lee way to use smaller (or larger) pinions.

First issue:
The Scorpion motor is nearly 1mm wider than the frame spacing. I cut the frame as shown to accommodate it. While I was cutting I opened the space mid-frame for potential access to the SK720. A rear mounted gyro is inaccessible in a scale body, and in my previous models I have made a custom platform on top behind the lipo, but this fuse opens well back so I should be able to access the gyro from inside the frame at that position. (SK720 likes to be near the C of G).

[Keyrigger]

Hi:

I mounted my 720 on a low plate at the rear of the heli and I have a permanently installed USB cable that sits beside the frame. You can see it here in this picture. It now has a CC Quik-Link to access the ICE esc. I did crash mine yesterday and it is back in the air this afternoon, but the repair of the paint will have to wait for winter. Take care.

Don



PS: I also had to remove some of the frame to install the 890 kV motor. Not a bg deal but I forgot to mention that. MB.

[npomeroy]

I like to be a able to physically access my 720 to check cables. I will be using the SK power buss.

Latest issue:
I thought I would be getting the 170T straight cut main gear and already ordered a range of matching pinions from Ready-heli with the 5mm shaft hole (Align motor is 6mm shaft). BUT the kit has the 112T slant gear, and I can't find anywhere a pinion with those teeth and 5mm hole. (I thought the H60060 which has the correct hole would do but the teeth are finer). I MIGHT find a way to bush out the motor shaft but it sounds messy and there would still probably not be any smaller pinion available than the stock 11T. So I have on order:

H60019A Main Drive Gear/170T (H60019A)
HN6064 New Main Gear Case Set (HN6064)

My understanding is these are compatible with the newer OWB and associated tail drive gear. I will tell all when they arrive.

Don do you care to say what caused your crash?

[Keyrigger]

The premise of practising auto-rotations in mid air needs the rotor to spool-up as soon as practical after you abort the auto. When I set up my scale helicopters, I set the esc for a slow spool-up for scale appearance hence it started to spool up but since I had a long auto, it reset and the spool-up started from the beginning. It was slow, the descent was fast, and the ground got in the way. It landed in very tall grass on fairly soft ground but it bounced on its roof and the broken chassis mount didn't help things much. The gear broke, collapsing the right side to the ground and that also caused some extra breakage of the paint and gel coat. Oh well, the gear was replaced in minutes and the lightweight chassis mount was replaced with 5 ply aircraft grade wood. I would suggest you do the same with any plywood parts in your mounting kit to pre-empt any future breakage. Also, I would replace the two washers in the front with a similar thickness ply pad, drill the mounting holes and forget the washers as they are a pain to position. On the back, forget the nylok nuts and go with blind nuts in the adaptor plate. Take care.

Don

[npomeroy]

The replacement gear set arrived - the correct case set was HN6064BA - the store checked and put the correct one in. It matched the stock tail drive gear nicely.

I need to adapt the tail servo drive rod for the fuselage. The kit has a carbon fibre rod, and I have obtained the wire rod for a Compass Atom 5.5. It's a little bit short but I wasn't counting on getting an exact fit. There will be some bending and I may even fit the carbon rod at the servo end, and attach it to to wire nearer the tail. I've yet to receive the fuselage so I cant plan that aspect more exactly yet.

[npomeroy]

I've already bought a set of Align DS615 servos (and a DS650 on order) and on testing on of them one seems locked quite often when I try to move it and makes a different noise from the others (I asked about this in the electrics forum https://www.helifreak.com/showthread.php?t=458541 but no responses). The servos seem to work normally when connected to a signal.

I'm thinking I'll keep the 615's and check them out on the pod&boom, especially looking for any changes post flight. I even calculated that to replace them with MKS or Futaba servos would cost about the same as another whole fuselage, although I'd get some money back if I could sell the 615's.

Just "thinking aloud" here.

[npomeroy]

Here are some more images.
Because I'll want extra weight up front I made a platform for the ESC.
Mounted the tail servo under rather than on top of the bracket so the ball could point up - the SK720 uses very short serlo throws for rudder and the "correct" way tends to bind abainst the servo case.
I've also shown the SK720 bracket inside the frame.

[npomeroy]

Well, six weeks after ordering the fuselage it finally arrived (supplier was carrying version 1 and order in version 2 for me - holiday in China - holiday in NZ - parcel "held" for 2 weeks in transit). The TRex550 from the same supplier took less than 1 week!
I like it!
I could never figure out how the panel lines lines were done from looking at photos, but I see they are filled with a glossy black tape which looks odd in some lights but is overall very striking.
I have a lighting system but I don't think I'll install it: I had one in my AS350 and in daylight, even cloudy-dull, it was hard to see, and I don't think I'll be flying in very dim light. Also the existing dummy "lights" built in look good and I don't want to make extra holes for wiring.
I'm planning to fabricate my own landing skids, using T700 skid pipes (9mm OD) cut to about 300 mm long, with the upright parts probably bent from stock 6mm aluminium tube.
I've replaced the 4025-1100 motor (which is for sale http://www.trademe.co.nz/Browse/List...x?id=529581570) with a Hyperion 4025-890, with 170T 0.7M main gear and currently a 14T pinion.
I'll post fitting details as I get to them.

[npomeroy]

I've started trimming the fuselage as per the instructions to do some trial fitting. Like Don (Keyrigger) I'd rather keep the rudder control rod concealed. But I don't like the idea of a flexible cable so am looking at other ways to keep the control rod closer to the boom. If I re-position the link ball on the top, rather than bottom, side of the tail control arm, and dremel away some of the casing metal, and bend the arm out a bit to make room for the ball, then the control wire will be quite close to the boom. Hopefully the images below will show where I am referring to.

[Keyrigger]

Just like this and you will be fine. Remember to shorten the guides as shown in the instructions. They do not supply the screw and nut for the job but the head bolt and nut from a Blade CP work perfectly.



Take care.

Don

[npomeroy]

Originally Posted by Keyrigger

Just like this and you will be fine. Remember to shorten the guides as shown in the instructions. They do not supply the screw and nut for the job but the head bolt and nut from a Blade CP work perfectly.

Take care.

Don

Yes, I bent the lever first to give more clearance and fitted the link ball without needing to mill anything away from the tail casing.

Mine has the carbon tail control rod so the guide is different. I intend to replace it (at the tail end) with a wire pushrod from an Atom 500 and make my own guides from plastic tube held on to the boom the appropriate space blocks and tape of some sort. The wire rod is a bit short so I was going to keep the first 100 mm or so of the carbon rod at the front end and join the.

I note that the space inside the scale boom seems too tight to include the vertical stabiliser mount (see drawing) whose main purpose is to align and lock the tail casing in position. I may be able to round the top and bottom to fit. The instructions say to attach bolts from outside the fuse but it seems these would distort the fibreglass when tightened so I'm thinking of making the bolt holes in the fibreglass big enough so the bolt head (use socket or round head not flat like they say) disappears inside.

[Keyrigger]

Do not use the backing for the vertical tail unless you take a significant amount off. I didn't bother using it at all and used the supplied domed head socket screws to tighten the tail housing onto the boom. The top hole will be too close to the boom to allow both the modified vertical stab mount and the screw to be there at the same time, but stranger things have happened. The hole locations they give you are for the belt tail and the shaft drive is further out with the screw locations. Measure many times before drilling the holes. Even then, I still had to enlargen them so that it was really easy to insert the Allen Key into the screw head. Yes, I am aware of the change and forgot to take that into account about the carbon fibre vs wire pushrod, and mine is the wire. You can buy a boom for the 550E as a spare and it will come with the rod and extra rod guide. I used two only, and did not add any extras, yet it could be done to keep the rod from flexing much at all. The tail pitch lever on mine was the stock plastic version and did not need to be bent. You can see in the circled area the metal I removed from the tail housing side and see the ball mounted in the pitch lever. Hope this helps.

Don

[npomeroy]

Thanks for the comments Don. My push rod sems to be going OK with careful bending keeping it close to the boom at the tail end. I'm using plastic tube guides supported inside 1cm lengths of thick fuel tubing strapped to the boom.
For the tail housing I think I'll cut away most of the plastic vertical backing to keep the positioning lug, and poke it in from the back just to fix the position, and just screw the bolts in through the metal parts only, via holes in the fibreglass as you say just to admit the hex key.

[npomeroy]

So here is the "test bed" version ready for the fuselage. The hardwood slab underneath nearly matches the weight of the fuselage, the silver duct tape is holding on some bolts to correct the weight and c/g.





This is the rudder pushrod support - to keep the rod close enough to the boom to be inside the fuselage.



Here are the skids. They have distorted slightly in a minor ground bump and I am looking at off-the shelf alternatives. Please see http://www.scalerchelis.com/phpBB2/v...p?f=20&t=14871 for more detail of my queries in this regard if you are able to provide dimensions or more options. Don what skids are you using: They look like the "Tuf" gear?



So far I'm fairly happy with the flight. The CC ESC is governed to 1450 rpm with an 890 kV motor, 14T pinion, 170T gear. I did change the swash servos over to Futaba BLS252 for greater reliability - one of the original Align 615s was always a bit different from the others.

[Keyrigger]

I'm sorry to hear that the gear is not holding up. My original gear is the very old 600 3D set, H60040T. They are wider than the standard new gear that bears the 700 number. If you really get stuck, let me know as I have spares for those. I can't help with the Tuff Gear and I see that you have the dimensions of the gear from JestRR. Would a slight change in material be in order and weld or braze them rather than use the current method? Take care.

Don

[npomeroy]

Thanks Don. I'll see how the existing gear holds up. Scale landings should always be geeentle anyway and if something more unplanned happens even JestRRs gear may bend. I think the weak point is the boundary between the fibreglass (wetted with resin and pulled through with string a bit like cleaning a rifle barrel) and the CF tube (actually spare cut off from the stock 550 tail control rod). The fibreglass went round the curve into the straight region, but the last 3 cm or so towards the centreline was CF tube that joined the two sides together.

Edit: Actually looking up the H60040T set - it looks about perfect (only 1 cm narrower than my present gear). They seem to be in stock a few places so I may just order some. (Save you going through postage rigmarole). I presume they take the same diameter skid pipe as the later 600/700 gear?.

Originally Posted by Keyrigger

I'm sorry to hear that the gear is not holding up. My original gear is the very old 600 3D set, H60040T. They are wider than the standard new gear that bears the 700 number. If you really get stuck, let me know as I have spares for those. I can't help with the Tuff Gear and I see that you have the dimensions of the gear from JestRR. Would a slight change in material be in order and weld or braze them rather than use the current method? Take care.

Don

[Keyrigger]

I actually used the stock 550 skids with those gear. The 700 skids are longer if you want to trim them to a scale size. I have been told by JestRR that his skids will bend but only in a very hard landing. For the most part he said that all he needed to do was take the bend out and continue using them. I have not even flown my Ranger with the new shoes on it, sigh. I have got to hope for warmer temps in the next few weeks, I am getting a bad case of cabin fever, lol. At least the electronics change-over in my MD500 is keeping me really occupied for the time being. Take care.

Don

[npomeroy]

Yes I have used the 700 skids and shortened them slightly. I attached the cut off piece to the front end for shaping to get the horizontal "step" appearance. I really want to get this yhing flying again in the next few days so have modified 4 stock skid struts to make a wider version. I've also ordered the older wider ones you mentioned AND am on the verge of ordering a set from JestRR as well. My ones actually broke completely at the soldered T joint when I was trying to straighten a twist.

The images below show the alloy skids before painting, and the stock modified skids as attached after the alloy skids were destroyed. I spent hours making them but don't fret over the breaking (at least it did not damage the helicopter) as it is a learning corve and I learned new techniques from my mistakes.

I'll be making a few posts now as I get closer to the final fuselage installation.

Originally Posted by Keyrigger

I actually used the stock 550 skids with those gear. The 700 skids are longer if you want to trim them to a scale size. I have been told by JestRR that his skids will bend but only in a very hard landing. For the most part he said that all he needed to do was take the bend out and continue using them. I have not even flown my Ranger with the new shoes on it, sigh. I have got to hope for warmer temps in the next few weeks, I am getting a bad case of cabin fever, lol. At least the electronics change-over in my MD500 is keeping me really occupied for the time being. Take care.

Don

[npomeroy]

So here is what I did for internal strengthening: I laminated 4 layers of 1/32" ply to make two curved sections which are glued to the floor of the fuselage with silicone sealant (this stuff really grips the fibreglass, gap fills, and is resilient). the idea is that the landing gear is firmly bolted to the ply strengthening, with an added slab of 2mm CF to prevent the ply being crushed by the nuts. Four of the bolts are much longer and attach to the bottom plate of the mechanics, vis a rubber grommet for some shock and vibration absorption.

The stock fuselage kit includes ply pieces to extend the CF bottom plate to take the landing gear bolts. But I completely replaced the bottom plate with a thicker 2mm one and cut it to include lugs for landing gear attachment. Here is the stock and modified bottom plate.

[Keyrigger]

That's a really nice job on that bottom plate. Right about now, I am wishing I had a scroll saw at my disposal. I used to have one but either gave it to my father and now it may have been ruined in one of the many floods, or I sold it for next to nothing when I got out of RC many years ago. Sigh.

Don