Thunder Tiger UH-1Y Build

[kennethw]

I'm pretty new to RC Heli's, but like all new hobbies, one goes a little overboard. Although I have put a few Pod-and-Booms into fuselages, this is the first time I'm spending more time to make it 'nicer'. Don't mind all the messy epoxy and other unslightly things, still learning.

I'll break the build down into sections, but to start, this is my present fleet after selling nearly all my Beams except for one.


I'll be using a second hand Raptor 50 (don't know which model but definitely not the SE, but it's a V2 I think) that has been converted to electric.


Motor: Scorpion 4035-400
ESC: Kontronics Jive 80+HV
Cyclic Servos: Align DS610
Stablization: Skookum SK360
Tail Gyro: CYB Solid G
Tail Servo: JR8900
4-Blade Head: Century
4-Blade Tail: Century
Battery Power: 10S or 12S (still testing)

Main rotor will spin CCW and tail will be on the left.

[kiratime]

I'm pretty new to RC Heli's, but like all new hobbies, one goes a little overboard. Although I have put a few Pod-and-Booms into fuselages, this is the first time I'm spending more time to make it 'nicer'. Don't mind all the messy epoxy and other unslightly things, still learning.

I'll break the build down into sections, but to start, this is my present fleet after selling nearly all my Beams except for one.


I'll be using a second hand Raptor 50 (don't know which model but definitely not the SE, but it's a V2 I think) that has been converted to electric.


Motor: Scorpion 4035-400
ESC: Kontronics Jive 80+HV
Cyclic Servos: Align DS610
Stablization: Skookum SK360
Tail Gyro: CYB Solid G
Tail Servo: JR8900
4-Blade Head: Century
4-Blade Tail: Century
Battery Power: 10S or 12S (still testing)

Main rotor will spin CCW and tail will be on the left.

Hi
Don't mind im interested in the E conversion,mind if you take pic post it??
Thanks

[kennethw]

Electric Conversion

The conversion to electric was with an old Hacker conversion kit. I've seen more elegent conversions, but am too lazy to do it. My limitation now is the gearing which is a potential challenge yet to be confirmed. As such, I'm stuck with the R50 gearing of 8.5 or 8.6 or R30 gearing of 9.5.


I had to build a platform for the ESC and also to hold batteries on either side of the mechanics.



The rest of the electronics were mounted all the way to the front.

[kennethw]

Century 4-Blade Head

I received my Century 4-Blade Head on Monday. Although the quality seems to be quite good, the flaw that I have found is that the ball links are too close to the rotational axis and therefore very little swash movement gives alot of blade pitch.


If one goes my other 'standards' and as recommended by GyroBot, there should be at least 25mm, the Century ones is only 20mm. My other 50-sized FBL head is 40mm.

To try an increase resolution of the Servo, I had to remove the Pitch Push Pull Lever and do a direct connection.


Servo movement is good, but for -/+ 10 degrees blade pitch movement, the swash only travels 40% of what it used to do with the Flybarred Head or my RJX FBL Head on the Raptor.

Servo resolution for Aileron and Elevator is also very small which I hope will not pose a problem.

To make it rotate CCW, I had to punch out the One-Way Bearing and reverse it. This initially was a little of a chore because I was too gentle. Just had to hit it really hard.

To make it work for the Raptor 50, I had to mill down the main shaft by 2mm and bore out the Jesus Bolt hole to 4mm.

[kennethw]

Century 4-Blade Tail

Also received the Tail on Monday, and was very disappointed.

Firstly, the Ball Links that they supplied was for a 2.5mm screwthread, but the screws that were to be used are only 2mm. So, I had to go out and buy some which wasted a day.

The instructions mention that there is a Steel Spacer, this did not exist in the kit. The Century Grips are held with only 1 bearing which had a tremendous amount of play. I ended up putting a second bearing and using the Raptor 50 Tail Grips. Which was a trip to another Hobby Store and more expense.

To make the R50 Tail Grips work, I needed to cut down the linkage point and put new Linkage Balls (more expense).

When putting the Ball Links to the Slider 'star', you must not tighten too much as you need a little play for the distance difference when the grips pitch. Therefore, the Ball Links need to be cut down accurately to the same length otherwise the pitch of the grips will be different.

The Slider Star and the nut that holds the slider sheath is a little too large and rubs against the plastic slider case. These needed to be tapered by angle milling so that they only touch the Bearings.




I have built Cascading Tails with existing stock bits-and-pieces that work better than the Century one.

Putting the Tail on the left using the stock parts was also a challenge. Some cutting into the Tail Holder was necessary. But it works fine.

[kennethw]

Fuselage Lighting

For the lighting, I put 2 sets controlled seperately by the Tx. One for the marker lights and one for the landing lights. Unfortunately, I couldn't program 2 seperate switchs on my JR-DSX9 the way I wanted it and therefore ended up using a single 3 way switch:

Position One: All Off
Position Two: Only Marker Lights
Position Three: All On

Side Marker Lights:





Nose Lights:



Tail Light:



Light Switch:


Cockpit Light:


Top Light:

[kennethw]

Nose and Cockpit

6" 'dolls' fit perfectly. Unfortunatly, I stole my son's Power Rangers and torched them to bend their legs. I was looking for McFarlane toys, but the distributor here in Singapore stopped bringing them in awhile ago.



Cockpit Details:


Flooring:
Built a floor to add Collective, Peddles, Sticks and other things later.


Wipers and 'Railing':





Tinted Sun-Shade:


Door Handle:


Will be adding overhead consul.

[kennethw]

Test Flight of the Mechanics

The rain finally stopped after 2 weeks, but there will be more to come due to the monsoons.

Went to the popular site which was like a marsh on 5th November 2009. Decided to put on 550mm blades because the Century Head is pretty big and when the 600mm blades were on, we flexed it to see if it touched the tail blades and it did. On the actual UH-1Y, I'll try the 600mm blades because according to my measurements, the tail will be moved about 70mm backwards, so there should be enough space.

Found a reasonably dry spot and started to throttle up, but no headspeed even at 100%. Then the Kontronics gave me 8 flashes: "Extreme Overload Error" and locked me out. So, that was a real bummer.

After running all my 'chores' for the day, I reset the Kontronics and went to the little open area at my apartment a little larger than the size of my Living Room (5m x 8m - the space that is) to try hover the mechanics.

I was a little worried because when I spooled up the mechanics without blades the night before, I noticed that the head was not 100% 'straight'. I believe that there have been others who have complained about this of the Century Heads.

My worries were realized. The head is definitely not straight and if you made all the links 100% identical in length, you will see the wobble and non-tracking of all the blades. Honestly, this is the first time that I have seen this in any of my Flybarless or Multi-Blade Heads; I usually just make the links identical in length and the tracking would be perfect.

The mechanics were flyable, but control was not 100% as expected due to incorrect pitching of the blades for the different inputs.

I have since individually checked for zero pitch difference in the blades by using one as reference and will go fly again tomorrow.

However, tomorrow I shall be trying a get of 10S. Today, I was using 12S and at 1400RPM the throttle was at 30%, at 1500RPM it was 36%. At 1400RPM, flying was a little difficult due to the incorrect pitching of the blades and slower reaction when input was given.

Since re-doing the head setup, I'll try to go down to 1350RPM the next day.

[kennethw]

Test Flight of the Mechanics ... cont.

Tried out the 10S batteries on 7th November 2009. At 1500RPM, the Throttle was still only 57%. As such, I shall be swaping out the R50 pinion and gear to the R30 one to give me a 9.5 ratio.

The flying was a little 'interesting' today. When giving forward elevator, the heli would tilt forward and left; mirrored for backward elevator. Needless to say, right and left Aileron input was not 'correct' either. To correct this, I had to give the SK360 an additional 10+ degrees advanced phasing.

I've just placed an order at Hobby City for 6 x 5S batteries, so there will be no more test flights for the next few day. Hopefully the batteries will come by the end of the week.

Meanwhile, I'm going to source for longer Linkage Balls to replace those in the Century Main Blade grips so that I get better resolution.

[kennethw]

Test Flight of the Mechanics ... cont.

The 5S batteries arrived from Hobby City 11th November 2009. Deans have been soldered to them, Balanced and Charged. Whilst waiting for the batteries, some other 'modifications' have been done to the mechanics.

The Pinion and Main Gear has been changed to the Raptor 30 to give a 9.5 ratio. Now, at 1500RPM, the throttle setting is at 77%. Hopefully the ESC will run much more efficiently than at 57%. Someone in another sub-section of RunRyder mentioned that JR's maximum throttle is actually realized at 86%, therefore the 'true' setting would be about 90% on the ESC which should be in the efficient range.

Another modification made was the linkage lengths on the Swash and Grips. I could only find SWIFT16 swash links at my LHS which are longer than the stock Linkage Balls on the Multi-Blade Grip, but shorter than the ones that came with the 4-Blade Swash. So, I put the longer Linkage Balls from the 4-Blade Swash onto the Blade Grips, and used the SWIFT16 Linkage Balls on the 4-Blade Swash.



Now, I get +/- 100% resolution for Collective Pitch, and +/- 70% on Cyclics. This is better than +/- 60% for Collective and +/- 55% on Cyclics.

As an aside, it is truely puzzling that Century shipped only 4 Linkage Balls with their 4-Blade Swash when it is obvious that you need 5. I guess it is their ploy to make one buy a set of the Steel Balls to use only 1. Anyway ....

Took the mechanics out for test flight and adjustments this morning. The mechanics was also weighed down with a 2 Pearl weight (dive lead) to simulate the weight of the fuselage. The whole setup including the weight and batteries is running about 5.3kg or 11.7lbs.

After 2 flights of swash and phasing adjustments, the mechanics can be hovered hands free for about 10 seconds before it starts to drift slowly (probably more due to the wind). However, 1 blade was very obviously not tracking, but I did not have anything on me to stick on the blades to find out which one it was.

3rd flight was to run large fast figure 8's and to see how much punch I have to pull up when the heli looses speed when slowing down. Must say that it does drop like a rock with that weight. To pull out of a 'fall', I think I was using about 8 degrees collective pitch. The heli is set to 10 degrees at the present time.

More test flights in a few days time to correct the tracking 'problem' and to do full pitch punches. Can't go the next because the wife revoked my 'permit'.

[kennethw]

Installing Mechanics into Fuselage

As of 16th November, I have made about 15 successful simple flights of the mechanics and getting impatient, so started to fit the whole thing together. So far, everything is going quite smooth, but hit a few snags.

Since I'm rotating the main blades CCW, the tail pulley mechanism need to be reversed to allow the tail to continue to spin upwards. First thing I noticed was that the bearing in the tail mechanism are not 'centred'.


Interestingly the instructions do not mention which plate to use on which side. Since they are flanged bearings, I assumed that the flange was on the inside so the bearing can't be pushed out and fall out of the mechanism.

To make it work on a CCW head, I needed to reverse the bearings so that the pulleys will mesh correctly. Luckily, the bearings came out with some light tapping.


The tail mechanism all in one piece.


Since everthing was reversed for the tail, including the tail being on the left, all the internal tail braces had to be reversed too.

After fitting everything into the fuselage, I know that I shall need to do further adjustments to the SK360. The original place that I put it did not allow me to access the switch or the connector. More importantly, I would not be able to see the light to see if the SK360 had initialized properly. As such, I added a small platform to the wooden frame and placed the SK360 there. I also cut away the front portion of the Raptor mechanics to make space for some Cockpit work. Now, I am able to easily see the SK360 light from the side window.


Made a rather large blunder while fitting the tail sections all together. I 'furtigued' the Tail push rod at the servo end a little without noticing it. When the entire tail was put together (everything including the covers and all), I noticed that the servo was able to pull but not push because it would bend right at the link joint. I also noticed that there is a lot of 'flex' in the wooden frame that holds the tail servo.

As someone else had mentioned in their build, once you put it together, it is nearly impossible to take it apart.

I managed to slide my hand in and pull the link off the servo and pulled the entire push rod out. Reversed it and put it back in and it seems to work because the bent part is now at the tail end and still inside the guide, so it doesn't bend. However, I'm going to get another push rod, better safe than sorry. I am also going to find a threaded metal rod that is about 10cm to link the servo link to the push rod connecting just inside the guide; this should give it more strength as this is the weak point due to lack of bracing.

Another blunder that I have made is that the last tail belt is a little tight, but can't do anything about that now, all epoxied together. On spool up (without blades), the rear belt housing gets warm, and typical of over tensed belts, the whole mechanism slows down very quickly on power down.

Hopefully this will not affect the Heli other than reduced flight time due to more power needed to drive the entire thing.

There was additional butchering of the mechanism because the Aileron Levers were a little wide and rubbed against the fuselage. The top Elevator push-pull ball and linkage was removed because that also rubbed; so, now there is only one control arm pushing the Elevator Lever. Hope this works.

I've fitted the 4-blade head back on and it sits really low. I have about 6mm to the top of the marker beacon, and 10mm to the top of the fuselage. On spin up, nothing seems to contact, so I'm taking the risk. I'll post some pictures.

[kennethw]

Installing Mechanics into the Fuselage ... cont.

Since Power Rangers are not really 'scale', I managed to find a couple of figures that just about fit: one is from Battlestar Galactica and the other from Resident Evil. It would be nice if I could get another one from Battlestar Galactica because they have helmets and all and make it look a little more 'real'. Unfortunately after combing many shops in Singapore, I could not find any.


Not a great job (I'll blame it on being the first time), but added some 'detail' to the cockpit. Stick and collective were made from wire, grommets and some wood.






'Kat' is pointing and looking upwards because I made poor attempt at making an overhead consoul of which she is supposed to be pushing a button or something. I could not find usable pictures of the overhead consoul that I could print and stick.


A better picture of the windshield.


I needed the doors to work, but don't know how to make a real slider. So, I ended up using magnets spaced evenly and put corresponding magnets inside the body so that the door will hold well. Now, I have 3 positions that I can have the door placed during flight.





I mentioned in my last post that the Head was very low. The following picture is with the blade holder over the light. I have spun it up and there is no contact, so hopefully it'll be OK.


The tail was by far the most difficult part of the build especially when the Head rotates CCW and the tail is on the left. Here are the results.





The whole thing put together.





Now, do I dare fly it. I'll have to wait for it to stop raining first ...

Hopefully my last post on this thread will be pictures of it flying (as opposed to crashing) ...

Oh, total weight is now 6.3kg or 13.9lbs.

[kennethw]

It seems some can't see the images. The images are actually on RunRyder. I don't seem to have edit rights to edit the links as I can load them onto DaddyHobby otherwise. hmmmm ...

[Super-Hornet]

BTW, u cannot put RunRyder link just like that. We will not able to see the pictures.

SH

[kennethw]

BTW, u cannot put RunRyder link just like that. We will not able to see the pictures.

SH

Oooops, just realized that. I spoke to Mike not too long ago and he'll be giving me Edit Own Post function, so I'll upload the images into DaddyHobby and redo the image links.