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Old Jul 11, 2012, 11:00 PM
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Century AS350 Military

It's been a very long time coming but I am finally in preparation for building the military version of the Century AS350 (been a while since I posted much of anything, lol). I ordered the body, three blade head, two sets of blades (looking for best balanced set), complete interior, all external bits, and the basket for external stores. I had (note the word "had") great expectations of converting a 550 to a 600 but that was a pipe dream as in a very hard verticle crash, the heli caught on fire and was a complete loss, less a few bits including the Skookum. I then passed on building another 550 and chose a 600 Pro E along with a new SK720 and a flybarless head setup (with a few more bits) that I already had as spare parts from the Jet Ranger.

Tonight, after a slight rebuild from a very hard landing, I did an experiment of running the 600 Pro on 6S rather than 12S. I reset the Castle ESC to allow a maxium head speed of 1120 (actual 1100 via an optical tach) in preparation for the three blade head. Not only does it work but it works better than I had anticipated so there may not be the need for another motor/gear combo to achieve a scale head speed. The lift will be stronger with the three blade head but it is workable right now and the current draws are rediculously low. A 6 minute flight only took 1300 mAH from a 3300 battery BUT that was without the weight of the body and extra battery to allow more current draw for the heavier system.

The body is backordered and I am now waiting for the Vancouver based supplier to ship the mechanical parts out as he finishes getting the parts together. I may be barking up the wrong tree with the stock 510 kv motor but the quietness is astounding. The main gear is the loudest component of the bird right now, lol. I have an idea that I will be making up a riser or modifying the ones that come with the kit to install the slightly lower mechanics of the Pro. I hope I have enough room to mount the batteries beside the frame rather than use the existing tray system (nice but limits the battery size to 3300 or smaller). I can hardly wait........

Don
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Old Jul 13, 2012, 10:34 PM
Love my scale Whirlybirds
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Mississauga, Ont., Can.
Joined Sep 2009
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As an update, I did some fairly agressive flying last evening (Thursday, as the post was very early Thursday morning) and the results are not as good as I had thought from the first flight. There is absolutely NO margin of error so if you end up in dirty air, it is entirely possible to loose lift and crash. It can happen to full powered models, yes, but you really need to be careless to get into that condition, whereas this setup does not have the torque to get the blades digging air hard enough to get out of that condition. I will go with the 890kv motor, running 6s with an 11 tooth pinion and the 112 tooth main gear. I will post pics as the project comes about as the chassis is just a stock 600 Pro. Take care.

Don
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Old Jul 14, 2012, 02:54 PM
Redjestird Youser
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Sounds good, I look forward to seeing this as a preview...I'm thinking of stuffing a stretched T500 into one of those AS350's (I have a 3 blade head that will take 12mm blades w/8mm shaft...so that's the catalyst).

With the 600 Pro...does that still have the ~4.5:1 tail ratio or does it have the new slowed down tail ratio to compensate for ballistic headspeeds? Might be an issue with lower speeds/weight/etc.
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Old Jul 14, 2012, 06:07 PM
Love my scale Whirlybirds
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The 600 Pro has the slowed down ratio, 3.85 to 1. I will most likely have a head speed in and around the 1300 rpm mark, when I put the AS350 together, which should give more than enough thrust to compensate for the torque and weight. At one point, I ran full all out rpm at 6s by running the esc still setup for the 12s pack. The results were 1390 rpm at the head, in the air under load, which proved to be more than enough to hold the tail solid as I did a full collective ascent. I do agree that the tail is not fast enough to hold at 1100 rpm doing the same maneuver. I tried it, which is one of the reasons I will not be using the 510kv motor. Take care.

Don
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Old Jul 16, 2012, 11:53 AM
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Originally Posted by Keyrigger View Post
The 600 Pro has the slowed down ratio, 3.85 to 1. I will most likely have a head speed in and around the 1300 rpm mark, when I put the AS350 together, which should give more than enough thrust to compensate for the torque and weight. At one point, I ran full all out rpm at 6s by running the esc still setup for the 12s pack. The results were 1390 rpm at the head, in the air under load, which proved to be more than enough to hold the tail solid as I did a full collective ascent. I do agree that the tail is not fast enough to hold at 1100 rpm doing the same maneuver. I tried it, which is one of the reasons I will not be using the 510kv motor. Take care.

Don
That is one of the disadvantages to using mechanics that were designed for 3D, which today are designed around very high rotor speeds (in excess of 2200). Consequently the tail rotor rato will have to be dialed down. Unfortunatly, for lower head speeds, that means the tail rotor speed may be too low for accurate precision and tail power for scale flying.

If you can change the T/R ratio to a higher one (e.g. 4.7 to 5.2), all the better.
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Last edited by Cyclick; Jul 31, 2012 at 11:57 PM. Reason: spelling
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Old Jul 24, 2012, 02:29 PM
Love my scale Whirlybirds
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Just a quick update. I spent the better part of an hour on the phone with the distributor about what my goals are with the AS350. With his past experience in FAI and F3C, the goal is to get the best lift to drag ratio you can achieve which also gives you the best battery life possible. If you look at the current blades used by the guys at the top, you will see some interesting blades being used, as opposed to the current crop of high performance 3D or FBL offerings. I am going to experiment with some 570 mm symmetrical blades as well as the originally ordered 600 mm semi-symmetrical blades. I am going for a head speed in and around 1400 rpm or as low as 1300, if the mechanics have the torque to lift the mechanics and body at a very good rate. The flight performance of the heli with the Skookum is fantastic and the battery draw is seldom more than 2200 out of a 3300 45C battery. Yesterday, I got my DX18 and spent the better part of 6 hours programming it and binding it to 8 of my heli's. If you did not know this, the settings from your DX8 will work perfectly, item to item, on the DX18 but you cannot transfer any models directly from your present group of aircraft. That is why I was so long getting it ready to fly this evening (if the weather co-operates, lol). I might see some parts this week!! Take care.

Don
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Old Jul 24, 2012, 06:56 PM
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DX18...nice. Any nice added features from the DX8 that stand out for you?
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Old Jul 24, 2012, 10:00 PM
Love my scale Whirlybirds
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Mississauga, Ont., Can.
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To be truely able to assign any function to any available switch, lever, or button, is worth the price of admission. I will most likely never use half of the computer wizardry inside it but the chance in the future to take advantage of it will keep it in my field kit for a very long time. The screen has a finer resolution allowing more to be shown per page but it requires me to use my glasses, whereas I could get by without them working with the DX8.

This evening, I went to the field for some easy going flying, and the 600 Pro was flawless with the DX18. My Jet Ranger was the spoil-sport and required me to set the end points of the CC ESC from scratch. That's not too much trouble, but when sunset has just occured, powering up the heli and getting no throttle response was not what I wanted with only 20 minutes or less to fly. I still got in two flights and the lights really make it stand out so I am really looking forward to installing them in the AS350. Take care.

Don
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Old Jul 25, 2012, 11:47 AM
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To be truely able to assign any function to any available switch, lever, or button, is worth the price of admission....Don
It was that feature that made me switch from JR10SXII to Futaba 9ZH over 10 years ago! And I have never looked back since.
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Old Jul 29, 2012, 09:54 PM
Love my scale Whirlybirds
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Mississauga, Ont., Can.
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Some pictures of the donor helicopter before. A bit subdued in colour as it was done after sunset and the light level was dropping fast. Take care.

Don







PS: The two lights on top of the tail boom mount are the Spektrum remote and the Skookum indicator.
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Old Jul 30, 2012, 11:52 AM
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I like that new full-coverage Align canopy...looks cool! (First I looked at a photo of these)
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Old Jul 31, 2012, 08:56 PM
Love my scale Whirlybirds
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The landing gear is also from the F3C variant of the 700, so it is a bit shorter in height and a bit narrower. Because of the angled gear, it does not sound like it is turning at 2150 (in those photos) and when it is reduced to 1700, it really is quiet, almost too quiet. The battery and electronics really do fill out the nose of that canopy.Take care.

Don
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Old Aug 01, 2012, 02:01 PM
Love my scale Whirlybirds
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The head, follower, head button, and scale 600 mm blades found their way to my doorstep this morning. The swashplate and a replacement blade grip (ball link hole was stripped) are on their way at the end of the week or early next week. I am getting ready to take out the 12s 510 kv motor and install the 6s 890kv motor as soon as the outstanding items arrive. I am sure that I will need to install either the 600E mainshaft or get the 600N shaft if the E version is still not high enough. There is quite a difference in head dimensions above the Jesus bolt hole with the Century head being the lowest of all of them. Only time and the arrival of the scale body will tell. Take care.

Don
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Old Aug 07, 2012, 08:53 PM
Love my scale Whirlybirds
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The swashplate arrived today with the blade grip which is now installed and awaiting the body. That should be in stock this week and out to me by next week sometime. There is a ton of small bits and pieces that I ordered to complete the exterior and interior so I hope they also make it in with the body. This is going to be a major job as the body has been spaced for the much larger 600N frame and even that is not as tall as some that fit in this body. The one thing that I want to get on the money is the relationship between the body, swashplate, and head. Painting the head will help bring its looks a bit more scale as I just cannot bring myself around to buying that work of art from Scalemodels.de. WoW, is it on the money but there are not enough events around here to make it worthwhile. If I win the lottery, ok. I need to start taking pics of this and need to get my card reader from work as my camera is so old that it can't be used to connect to my computer. Canon completely dropped all support for older cameras and Win7. I have some choice words for them and they are not printable here or anywhere else, for that matter. Take care, lol.

Don
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Old Aug 08, 2012, 09:27 AM
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Originally Posted by Keyrigger View Post
. as I just cannot bring myself around to buying that work of art from Scalemodels.de.
This one? Yeah, that is real cool looking for sure
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