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Post by wolveslayr on Sept 27, 2011 13:10:46 GMT -5
Greetings all, glad to find you. My name is Todd and I need advice. I bought a plastic 425 when I realized starting with a 450 would make it more difficult to learn CP. I have years of sim, some B400 and CX2 experience.
I thought the 425 would provide more stability but immediately recognized the 550 would give me a better chance at success. I have a Turnigy 1300kv and 430 woodies.
So my question (piggy bank budget). What is the largest blade length I can fly with the original 425 boom. I guess not much bigger than the 430's
That aside I would like to stretch it. Many have said they like their 500's best. Does that mean 500mm blades on a 500 boom? or 500 blades on a 550 boom?
Being on a strict budget I have to make good choices. So I concluded: get the 550 boom, the 500 blades and since I have a 1300kv motor w/15T pinion I would need a 42T up front and a 20 T OWB. Gives me HS of 2632 w/ 15T or 2457 w/14T.
I used 75% efficency as it is a turnigy motor. Which may be a correct assumption. Yet a higher efficiency the hs gets too high. I can't afford a $100 motor now or I would look at 550mm blades.
Am I thinking along the right path? I have read most of HK and read most of your posts.
I want a super stable platform to give me stick time and not break the bank.
Any thoughts appreciated.
Todd
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Post by dunkonu23 on Sept 27, 2011 14:04:21 GMT -5
Todd, Welcome! I would go with this: rcdumbthumbs.com/G-204662.aspx for your boom conversion. Add in 500mm blades. One thing I'm not certain of... if you were converting to a 550, I'd be dead on certain, but since you're looking at 500mm, I'm not too certain if your headspeed is going to necessitate getting a CNC Head assembly. Jerry? Scott
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Post by wolveslayr on Sept 27, 2011 14:22:48 GMT -5
I guess in the 100's of posts I've read I see them talking about their 550's only to learn later they are flying 500mm blades.
I'd be nice to know which blades they fly with their 550's. From what I have learned, if I went 550mm blades right away I'd have to get a motor 980kv to 1100kv. Which I can't this month.
So a 1300kv hk motor (said to be ~1400kv) with a 15T 42-61-20 gives me 2400-2500 HS on 500mm woodies.
Is that to much HS for 500mm woodies? Should I keep above gearing and go to 13T or some other combination.
TIA
Todd
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Post by ptcaflyer on Sept 27, 2011 23:49:02 GMT -5
On my "500" (Plastic 425 frame, MID BOOM, 980kv Z-Powermotor, 100a Hobbywing Platinum Pro ESC) I run that head speed with the Gaui 500 wood blades...No problems at all...i would rather they be CF, but I'm on a budget too and cannot afford them...for 15.00 a set, I can buy a lot of them and still have cash for other things... my 550 is the plastic fantastic also with 550 GF blades and the stock 850 Gaui motor...turning around 1900 HS...sometimes you can find bargain Align 520 blades that will work on the 500. PT
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Post by Jerrymac on Sept 28, 2011 1:01:44 GMT -5
Welcome Todd. Hope you don't mind my late response, but, I don't get home from work till midnight every night. I will try to do my best to help answer some of your questions also. As for the boom length, I use the medium length boom that Scott linked to on my 500mm bladed Hurri. I have heard of people running the long boom with 500's also, but I have never done it so don't know if it has much affect on flying characteristics. I believe the 500mm woodies are rated at a max of 1900 rpm if I remember right. I had done many test flights on my medium-boomed, HeadHunter framed Hurri with 500mm woodies, running a head speed of around 2300 to 2400 with no problems, however, that doesn't mean I would recommend that others use them at over their max rated rpm. Just sayin... If stability is what you want, you can't beat the long boom and 550's. Keep in mind that you could use that motor with a 14T pinion and a 60T primary gear and get a head speed of about 1800 to 1900 and run 550's, but the motor will likely bog with quick collective pitch stick inputs. If running 550's is your goal, you could try that till you are able to get a more suitable kv motor. Here are links to some decent low cost 550mm FRP and CF blades. helidirect.com/550mm-pro-3d-frp-fiberglass-main-blade-p-11215.hdxhelidirect.com/550mm-pro-3d-cf-carbon-fiber-main-blade-p-11214.hdxOn the Turnigy motor, I doubt the efficiency rating is that low. Probably more like 85% or 90% would be my guess, so running 500mm blades you would need something like a 14 or 15T pinion and 50T primary gear to get a decent head speed. One upgrade I would recommend is the CNC swash plate guide. I just don't trust the plastic elevator arm to hold the swash plate in place. Scott also mentioned the CNC head assembly. The entire CNC head assembly is $300, so that can get quite expensive. The 'performance upgrade kit' includes CNC head block and main blade grips and is a nice upgrade. I have the entire CNC head on my HeadHunter framed '500' and the performance upgrade kits on my other Hurri's. Not sure how much head speed the plastic grips can handle, but, I will let you know this weekend, lol. I am going to maiden my new "low cost" 425 build running 2900rpm and all plastic head and tail. Hope this helps more than it confuses. Keep us updated on your new build, and if you need help, just ask. Jerry
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Post by wolveslayr on Sept 28, 2011 19:58:56 GMT -5
Thanks to Jerrymac and all the others who took the time to try and help me make good decisions. I don't think there are many helis where you have so many variables to consider.
I'm looking for stability with my first big bird. Since I will have to upgrade over time. I think I will get the long boom and a couple pairs of 500 woodies along with shafts and spindles. Then continue to plug numbers into nexgen's spread sheet to get the proper HS at a higher efficiency than I was using and buying proper gearing.
I've made to many mistakes in 15 years of RC to be guessing and throwing money away on the wrong parts. Now I like to ask twice and buy once. ;D
Thanks again.
Todd
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Post by wolveslayr on Sept 29, 2011 6:51:09 GMT -5
Jerrymac, I've owned several heli's none approaching this size but the last thing I would have thought is a recommendation to upgrade the swash guide. Obviously I can't ride it to see the forces it takes. Yet I totally believe you! The CNC head assembly is out until work starts again ;( but I need my hobbies to stay active and sharp. So I took the Gaui path putting a HK450 on hold to get my CP thumbs trained first. So I'm thinking the the 1300kv Turnigy which I rounded up to 1350 since many say it is closer to 1400. I'll do a 14-15T pinion, then 60-20-61. I'll put the 20 OWB in there just because of problems I read with the 19 OWB. The 550 FRP's which shouldn't have the HS limitation of the woodies.....OR I could get the mid-boom and fly it with my pair of 430 woodies and take my chances with a squirrelier bird. Naa, I thing long boom with 500 woods or 550 FPR with proper gearing will do more to make me a better pilot, not a better builder. Lastly I have maybe 10 pair of blades, 325 Align woods, HK 325 CF, more 330 woods and 2 pair 430 Gaui woods. That said I don't think I've ever seen a HS limit on any of them unless I stop reading at 4 lines of Chinese. lol Thanks for letting me think out loud...it helps
Todd
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Post by wolveslayr on Sept 29, 2011 6:56:07 GMT -5
Oh, and I am ordering the X5 tail hub and grips as I've heard people say the larger disk provides more authority, bigger blades w/bigger fin. Also the X5 flybar (400mm)
T
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Post by dunkonu23 on Sept 29, 2011 8:09:23 GMT -5
I used to use a T-rex 600 flybar with T-rex 600 paddles on my Flybar'ed 550. The X5 tail hub is probably a great choice. Just make sure you get gains right. What gyro are you using?
Scott
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Post by wolveslayr on Sept 29, 2011 17:09:59 GMT -5
I've got an Assan mems and a HK 401b. A B400 which probably stay in the parts bin.
I found an owners manual for a 550 today and it has so much more information than the 425.
Was thinking I could put thrust bearings between the two ball bearings but the grips I think would be different.
Todd
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Post by wolveslayr on Sept 29, 2011 17:18:00 GMT -5
Ino-lab 261 on the tail.
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Post by dunkonu23 on Sept 29, 2011 17:49:11 GMT -5
I don't know anything about the gyro you're using, but I think the servo would work if you were to keep it at a 425, but larger? It looks like a mini-servo. So, I'm thinking you would need a bigger servo.
Scott
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Post by wolveslayr on Sept 29, 2011 18:48:33 GMT -5
Yup, this all started in the middle of a HK450 build when I learned something bigger would be better. I found the Gaui, bought it and then after shipping learned about stretching. It's the ino-lab D261HB and is about 5mm shorter than my cyclics. Re-reading the description it says for 400-500 heli. So now I see in retrospect I didn't understand sizing. This may delay any boom lengthening. It was for me an expensive tail servo. www.heliflightcenter.com/INO_LAB_HG_D261HB_DIGITAL_TAIL_SERVO_p/hg-d261hb.htmI guess the Trex fly bar, X5 (Trex600 ?) tail hub and grips might be it for a while. Heck the Align fly bar is 440mm and mains are 430 so that's probably not a great idea. I do have Trex 600 skids. So for a 550 boom besides speed what kind of torque do you want? This one is 3kg/cm TIA Todd
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Post by Jerrymac on Sept 30, 2011 2:27:41 GMT -5
Well, a few more thoughts. I am not familiar with those gyros, so can't comment on them. Although I would agree with Scott that a mini servo might be too small for the 550, I did some checking on servo specs and found that the JR DS890G on my 550 is rated at less than 3kg/cm and works great, so, I dunno. I do use a mini on my first 425 build though, a JR DS3500 and works well on the 425. I have full size Hyperion's on my other 425 and HH 500 though, DS 20 GMD's.
If you are just doing some hovering and starting out in forward flight, that tail servo will probably do the job for you for now. A decent quality gyro will go a long way toward keeping the helicopter pointed straight, so, you might want to consider that your first upgrade if the ones you have are not up to the job. I run JR G770 gyros on 3 of my Hurri's and they work great. I recently picked up 2 used Spartan gyros from Scott as these were his favorite, but I haven't flown my new 425 with the Spartan DS760 on it yet, although I am sure it will work great too.
Often times you can pick up good used electronics for a decent price ( see my low cost 425 build thread ). Since I have a hunch that you are "wookiedumplin" (or something like that, lol) over on Freak, you might want to check out the classifieds there for future upgrades.
On the blade thing, I have a new package of Gaui 500mm woodies and their is actually a note in there that says "max recommended head speed" 1900, although as I mentioned in an earlier post, I have run them at 2400 with no problems, but don't recommend that others do it.
I have also heard that the X5 tail assembly is much better than the stock Hurricane one, but I haven't tried it yet, although I got one for my HeadHunter.
Jerry
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Post by wolveslayr on Sept 30, 2011 9:48:56 GMT -5
Thanks Jerry, I think I'll be fine with the servo. At least with 500mm blades. Haven't seen any Hurri's with the Chinese weight mod, which would help the servo. The gyros are pretty widely used but admittedly of the cheaper quality than one would desire. So that and a better motor will be next. At this point my goals are hovering in all directions and some fff. Years on the sim and a couple with much less of a bird has got my thumb memory very natural along with the small inputs required. Yes, I am wookiedumpling, lol. I have NO idea where I came up with that 3+ years ago when I visited HF for CX2 chat occasionally. Wish I could change it. So off to RCDumbthumbs for parts. I actually had the 8x12x3.5 bearing slip from its cradle while tightening the frame and the bearing just fell apart completely. No warning or noise or resistance. I'll take more care as that surprised me. Never in 15 yrs. seen a bearing just explode like that. Thanks again, Todd
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Post by dunkonu23 on Sept 30, 2011 17:26:27 GMT -5
Never had a bearing do that, either. I have had a bearing go to shreds, but that was after a really hard crash. Wow.
Scott
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Post by wolveslayr on Sept 30, 2011 22:44:01 GMT -5
Will a fiberglass 550 blade weigh more than a 550 woodie? Or although drawing more amps will the fiberglass 550 give me more control and stability at the price of flight time. I think I've got the gearing down, the implications. Not sure about the relative stresses these blades put on the motor, battery
Will I have a better flying with bird with a 550 frp blade or is wisdom on the side of lighter woodies with less stress, heat on the motor battery?
I'll quit asking questions now. I've probably overstayed my welcome. I promise my mind is almost made up. ; ) re: component choices.
Todd
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Post by Jerrymac on Oct 1, 2011 0:56:06 GMT -5
That is strange with the bearing, I have never seen that happen either. I don't have any actual 'facts' on the blades but I believe the woodies are lighter, which would be easier to spin, and should be fine for gentle sport flying. Wood blades are not nearly as strong as FRP or CF blades though, and could break with hard collective inputs. I have had wood blades break at the root with hard flying on my BH 450 before. I ran woodies on my 550 when I first built it and they seemed to fly OK, but as I got better at flying I replaced them with CF blades. One bad thing with wood blades is that they will not survive even a very minor blade strike as they will shatter, whereas FRP or CF blades can sometimes take a minor strike and still be useable. Don't worry about asking questions. That is exactly what we are all here for, to help others, and to share our enjoyment of the hobby. Soon you will be answering other peoples questions. Good luck with your new build, and let us know how it goes. BTW, nobody 'overstays' their welcome here. I enjoy hearing from our members every day. Most of us don't fly much during the winter, so we talk about snow. I have seen a few members over on Freak change their user names, so you might want to send Will a PM and ask him if he will change it for you if you don't like the one you originally chose. I don't think you can change it on your own, but, I think one of the staff members can. Jerry
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Post by dunkonu23 on Oct 1, 2011 1:22:02 GMT -5
In addition to Jerry's lucid and illuminating post on woodies, I'd like to add that FRP or CF blades will track better and be easier to set tracking.
Jerry would have to mention snow... Turned the furnace on for the first time since the end of April. UGH.
Scott
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Post by Jerrymac on Oct 1, 2011 2:02:36 GMT -5
Ah, Scott is right, I forgot to mention that. When I set up my helicopters with wood blades, and both blades at 0 pitch at mid stick, I ALWAYS ended up re-adjusting the links to get the blade tracking right. When I set up a new build with FRP or CF blades at 0 pitch at mid stick, I have NEVER yet had to adjust the blade tracking as they were spot on. The wood blades seem to flex more under load and track differently when loaded. Scott, I had to turn the furnace on tonight too. Gotta fire up the ol home made log splitter this weekend and get some fire wood split and stacked up in the basement. When I have a fire in the WoodChuck, the furnace never runs. I plumbed it right into the heat and return air ducts in the basement, so it is very efficient.
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