Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopter Support > 250 Class Electric Helicopters


250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


View Poll Results: What is the weight of your 250?
less than 320g 58 18.18%
320g to 340g 104 32.60%
340g to 360g 92 28.84%
More than 360g 67 21.00%
Multiple Choice Poll. Voters: 319. You may not vote on this poll

Reply
 
LinkBack Thread Tools Display Modes
Old 05-06-2016, 04:38 PM   #201 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

Quote:
Originally Posted by arcsnsparks View Post
I was wondering if the lynx 180 servos would fit the 250
It's definitely not a bolt-up mod. The bolt holes are different (more narrow) and I plan to make some adapters for them. The length and height of the servo arms is a concern. The height I can probably modify with adapters, but the length of the arms is going to be the length of the arms. I'm hoping 2/3 the torque of the stock servos is adequate, it should be but don't know for sure how well things will work until I try it.

Also the wires on the Lynx servos are very light gauge and use JST 1.5mm connectors. I plan to change those out with heavier wires using the typical JR connectors. So it's a pretty involved mod all in all.

The 250 is really a pig in its stock form. It has to lose a lot of weight to get into a proper range for the size of the blades. Consider my next heli size down has 115mm blades and a quarter the weight. The next heli size up has twice the blade length and less than twice the weight. The relationship between ideal weight and blade length is not linear, but still the 250 is much heavier in ratio between blade length and weight.
Krager is offline        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 05-06-2016, 06:29 PM   #202 (permalink)
Registered Users
 

Join Date: Jan 2015
Default

Yeah I've had a few of the same thoughts about the 250's weight as well. I am not sure of the exact 180 cfx weight ready to fly but I seem to remember that it was around the 200g mark.

Basically I have figured up a 250 based on the lynx servos and a few other refinements that would get a build down to around a 225g build. It however would require a considerable amount of work and expense to get it there.

Consider after you make adapters and change out for heavier servo wiring what you are saving or gaining at that point. The servos are $125 and I can see adding a gram or more after wire, adapter and associated hardware. That has been what has kept me from going further than where I have gone but I do think it's doable. It will be interesting to see what shakes out and if it's worth it though.

Certainly if you are considering a build like that and need a few ideas hit me up as I may also be interested and have done a considerable amount of planning and prep towards that end.
__________________
Helis: Trex 250, Oxy3 +, 450 se v2, 450 pro, 470, 480N, 500 ESP, 600N, 700N
HeliLust is offline        Reply With Quote Quick reply to this message
Old 05-06-2016, 10:34 PM   #203 (permalink)
Registered Users
 

Join Date: Jun 2015
Location: KC MO
Default

I just don't think it's worth the hassle of trying to get it that light. 270g is PLENTY light for 210mm blades. Trying to make it lighter really makes you cut down on stuff and make stuff weaker, more likely to break, and more overloaded. It flies perfect on 210s without being 225g. Unless you plan to never crash ever, I'm just not convinced all the extra effort is worth it.

btw, using the 180 CFX for a weight comparison is not a very good idea - that thing is heavy as hell out of the box for the disc size.

Fly it at ~270-290g first with Zeal 210s and then make your judgement if you want to go further. I know I don't.

Just know at 225g with that big of blades, it's not going to handle wind well at all. Even at 290g mine gets blown around pretty good.
__________________
Keith - MSH Brain2 Beta Team
Synergy N556 | LOGO 480 XXtreme | T-REX 470LP | Blade Nano S2
FrSky Horus X10S Github Repository
https://kc3dprint.com - 3D Printing on Demand and 3D Printed RC Helicopter Parts and Upgrades
Number is online now        Reply With Quote Quick reply to this message
Old 05-07-2016, 12:30 AM   #204 (permalink)
Registered Users
 
Posts: 1,563
 

Join Date: Feb 2015
Location: Melbourne
Default

On windy days the 250 really gets blown around no matter the weight, having longer blades may help a bit.

I think the aim is to cut on the weight so that they can cut down on the HS.
gimbleguy is online now        Reply With Quote Quick reply to this message
Old 05-07-2016, 02:52 AM   #205 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

There's no substitute for weight in wind. The more weight the better. Of course there's a limit to where it costs too much in performance. It just kills off thrust ratio too much. I'll be happy to get mine down to my target which is relatively high compared to 270g. I don't see the benefit at some point as your digging into power and durability. There are places I'm willing to take on some weight, motor for one. Another one is metal bearing blocks. I want the power and strength those offer even with the weight penalty.
Krager is offline        Reply With Quote Quick reply to this message
Old 05-07-2016, 12:30 PM   #206 (permalink)
Registered Users
 

Join Date: Jun 2015
Location: KC MO
Default

Quote:
Originally Posted by gimbleguy View Post
On windy days the 250 really gets blown around no matter the weight, having longer blades may help a bit.

I think the aim is to cut on the weight so that they can cut down on the HS.
bigger blades without increasing weight would only making it worse, because the extra disc size would give even more area for the wind to blow on.

At 210mm, I think anywhere from 270-290g is perfect. Mine's at 292g with Zeal 210 and a (heavy) Pulse 860mAh 35C (16AWG wire!) and it flies AWESOME. It has shloads of power and is rock solid. I am comfortable flying in around 10mph with it as long as it's not super gusty. Having also flown a 350g Trex 250, while it does fly like shit, it handles wind like a champ
__________________
Keith - MSH Brain2 Beta Team
Synergy N556 | LOGO 480 XXtreme | T-REX 470LP | Blade Nano S2
FrSky Horus X10S Github Repository
https://kc3dprint.com - 3D Printing on Demand and 3D Printed RC Helicopter Parts and Upgrades
Number is online now        Reply With Quote Quick reply to this message
Old 05-07-2016, 01:32 PM   #207 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

Where do find that much weight to trim to get it down to 292g? I feel like I'm digging deep with mine and I'll be happy to get it to 325g.
Krager is offline        Reply With Quote Quick reply to this message
Old 05-07-2016, 01:52 PM   #208 (permalink)
Registered Users
 

Join Date: Jan 2015
Default

Talon 15 eSC , decased kbar and sat weigh as much as the stock align esc alone. I think the belted tail helps too. Just with the stock servos, talon esc, and kbar sat setup I was at 300g
__________________
Helis: Trex 250, Oxy3 +, 450 se v2, 450 pro, 470, 480N, 500 ESP, 600N, 700N
HeliLust is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 06:45 AM   #209 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

Just finished swapping out all the servos on mine with Lynx 180 servos. Lops off a big chunk of weight. Haven't tried it yet since I just finished it. There's a chance there may be an issue with torque output, but they have 2/3 the torque rating of the stock ones which are actually 450 servos. The Lynx servos are also a lot faster both rudder and cyclic.

It's a big mod to switch out those servos for smaller ones. Took me some time. Changed out wires with longer ones having JR connectors. Had to make adapters to fit the servos in the existing servo mounts. Needed to reinforce servo horns with CF. An odd problem I ran into is the Lynx servos in the plastic version doesn't have a very good thread bite on the screws (they have a version with metal case ends). A lot of them stripped so I had to repair threads with CA. Big design ding on that. Probably worth using the metal case ends just for that reason, but I'm sticking with the plastic for now since they're lighter.

Otherwise the servos are no issue with the BeastX controller I'm using. Everything went fine with controller setup. I didn't have to change any servo directions. Was happy about that since I wasn't sure servo directions would be the same. Another nice thing about these Lynx servos is they have better pots and less slop than the stock ones. Action is noticeably smoother and tighter. Generally my feeling is that Align (Savox) servos pretty much suck. I won't be using them ever again.

The heli is at 329g now all up weight. That's using a 75g 850mAh battery. There's some some weight I added running a heavier motor and some metal parts like bearing blocks and rudder servo mounts. Less those additions it would probably weigh in around 310g.

I found out the hard way the belted tail saves 3g. I bought the parts I thought I would need to switch it over, but was not happy to find the pitch slider mount on the tail shaft case is different. I'd have to switch over to the old style pitch slider which I don't want to do since the Pro DFC one is a lot nicer.

Here's how it looks;
Attached Thumbnails
Click image for larger version

Name:	P6220533.jpg
Views:	60
Size:	110.5 KB
ID:	658515   Click image for larger version

Name:	P6220535.jpg
Views:	1281
Size:	127.7 KB
ID:	658516  

Last edited by Krager; 06-22-2016 at 07:59 AM..
Krager is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 07:03 AM   #210 (permalink)
Registered Users
 

Join Date: Apr 2013
Default

Shouldn't be a problem with 2/3 of the torque, the 250 is still using the same size servo as 360mm or even 380mm machines. The servos are massively overpowered on this model.
__________________
Helis: Oxy2 FE, Oxy2 Sport, Protos 380, Oxy 4 Max, Gaui X3 stretched
Electronics: Spartan Vortex, MSH Brain, Jeti DS-14
Sims: RealFlight & AccuRC
Other: Team rep for Lynx/Oxy, Founder of NightWave Systems
myxiplx is online now        Reply With Quote Quick reply to this message
Old 06-22-2016, 08:00 AM   #211 (permalink)
Registered Users
 

Join Date: Jan 2015
Default

Nicely done, I was considering doing the same thing to mine but opted not because the cost of the servos. I'm now sure what mine weighs right now, I've made so many changes trying to get it all sorted out.

My tail is being so difficult to get dialed in its not even funny. It's getting better slowly but still leaves a lot to be desired. Right now I'm fighting with tail kick on hard pitch changes. I'm making progress though and think it will be sorted out soon. Other than my tail issues it feels great in the air.
__________________
Helis: Trex 250, Oxy3 +, 450 se v2, 450 pro, 470, 480N, 500 ESP, 600N, 700N
HeliLust is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 08:11 AM   #212 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

Quote:
Originally Posted by myxiplx View Post
Shouldn't be a problem with 2/3 of the torque, the 250 is still using the same size servo as 360mm or even 380mm machines. The servos are massively overpowered on this model.
That's good to hear. I don't know when I'll get to try out these much lighter servos. The weather has not been cooperating here lately, too windy.

Yeah the T-Rex 250 is a bit of an odd duck the way it's built. It's pretty much a scaled down 450 which is good for durability, but bad for loading having such a smaller disk.
Krager is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 08:25 AM   #213 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

Quote:
Originally Posted by arcsnsparks View Post
My tail is being so difficult to get dialed in its not even funny. It's getting better slowly but still leaves a lot to be desired. Right now I'm fighting with tail kick on hard pitch changes. I'm making progress though and think it will be sorted out soon. Other than my tail issues it feels great in the air.
I was having some trouble with the tail holding perfectly on mine, but after putting a bigger, higher Kv motor in it and upping the head speed to 4500 rpm governed it solved the problem. I also went to a slightly longer KBDD tail blade.

I really did not get very satisfying flight performance out of mine until I went to a more generous head speed. The lower weight should make it even more impressive. I like it when my helis move out like crazy when you pin the collective. There's something I find really satisfying about that. There's a video of a guy running 5500 rpm on a trex 250 and that heli punches out like nothing I've seen. No way to get that with 3S though, maybe 4S, but probably 6S.
Krager is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 08:38 AM   #214 (permalink)
Registered Users
 

Join Date: Jan 2015
Default

I've switched out to larger tail blades and it got rid of the blowouts I was having with the 37's, I now run wide cord 42's that I've made from 300 cfx blades. I still can't get rid of the kick on hard collective though. Head speed doesn't really help much either.

It's getting better slowly though. I think it's just a matter of getting it all balanced and dialed in now. The biggest problem is the kick isn't allways consistent , sometimes it's 20* others it can be 45* or better.
__________________
Helis: Trex 250, Oxy3 +, 450 se v2, 450 pro, 470, 480N, 500 ESP, 600N, 700N
HeliLust is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 09:15 AM   #215 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

That sounds like a good way to go on the tail blades. Mine are okay now, but if I change something where I need more out of the tail I'll keep those blades in mind.

I actually would like to run a somewhat longer main blade on mine. I think there's room for another 20mm. Though it's not like there's much option there. You need parts for a stretch and I've not seen there's anything available. Generally you don't see a lot of aftermarket parts specifically for the 250. It's just not a popular size. It's good for me though. There's a field across from my house just right for that size heli.
Krager is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 02:09 PM   #216 (permalink)
Registered Users
 
Posts: 1,812
 

Join Date: Jun 2009
Default

Quote:
Originally Posted by CraigHB View Post
There's a video of a guy running 5500 rpm on a trex 250 and that heli punches out like nothing I've seen. No way to get that with 3S though, maybe 4S, but probably 6S.
You can get over 5500rpm if you use a 16T pinion on 3s battery.

I run my 250 at 4700rpm in IU2 and itís a little monster. I have tried running it at 4900rpm but it was just a waste of energy as 4700rpm was enough.
I was running the 16T pinion before but I found I did not need more than 4700rpm, which I got from using 15T pinion. I switched back to the 15T pinion.
__________________
T-Rex 550E V2 Spartan VX1n, T-Rex 250 PRO DFC Spartan VX1n, Blade 130X. Futaba T8FG Super

Toocool4 is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 02:36 PM   #217 (permalink)
Registered Users
 

Join Date: Dec 2014
Location: Seal Beach, CA
Default

Quote:
Originally Posted by Toocool4 View Post
You can get over 5500rpm if you use a 16T pinion on 3s battery.

I run my 250 at 4700rpm in IU2 and it’s a little monster. I have tried running it at 4900rpm but it was just a waste of energy as 4700rpm was enough.
I was running the 16T pinion before but I found I did not need more than 4700rpm, which I got from using 15T pinion. I switched back to the 15T pinion.
I guess if you say it's possible, but I have issue with current demand. As it is mine peaks 20A with 3S at 4500 rpm. I have a 25A ESC and the battery can probably handle it, but I'd rather not load it any harder. Taller gearing would further increase current demand. If I was going to run it that hard (5500 rpm), I'd try do 4S at least, probably 6S just to minimize currents.

This damn wind I'm getting here is really starting to annoy me. It's been windy for like a month straight. I wanted to see how the heli does with the new servos even though it was really too windy to fly. Mainly wanted to see if it had any major problems. So I managed to run a pack through it today, but it was just a hover with some pitch pumps since the wind was really too strong to do much else. I need some calm weather to get things tuned up. The dynamics are a bit different with these servos. The horns are a bit shorter and the Align servos had more travel. It's enough that it throws things out of tune a bit. Once I get things dialed-in I'll be able to tell a lot better how these servos work, but so far they seem to work well. The heli seems more precise as far as I could tell between gusts of wind. And I really noticed the drop in weight.
Krager is offline        Reply With Quote Quick reply to this message
Old 06-22-2016, 02:45 PM   #218 (permalink)
Registered Users
 

Join Date: Apr 2013
Default

Fwiw, I'm running the 16t pinion with 3S packs and a Talon 15, and 4200 to 4500rpm. It'll handle an entire flight of tic-tocks with no problem. :-D
__________________
Helis: Oxy2 FE, Oxy2 Sport, Protos 380, Oxy 4 Max, Gaui X3 stretched
Electronics: Spartan Vortex, MSH Brain, Jeti DS-14
Sims: RealFlight & AccuRC
Other: Team rep for Lynx/Oxy, Founder of NightWave Systems
myxiplx is online now        Reply With Quote Quick reply to this message
Old 06-22-2016, 03:07 PM   #219 (permalink)
Registered Users
 
Posts: 1,812
 

Join Date: Jun 2009
Default

I am also running Talon 15's on 3s, and the 15T pinion without issues. So your Talon 25 will handle it no problem. To be honest i am in IU1 4300rpm most of the time and it does everything i need, just go into IU2 4700rpm for crazy stuff. If i ran IU2 all the time it would be a waste of power most of the time and the flight time would be very short.
__________________
T-Rex 550E V2 Spartan VX1n, T-Rex 250 PRO DFC Spartan VX1n, Blade 130X. Futaba T8FG Super

Toocool4 is offline        Reply With Quote Quick reply to this message
Old 06-23-2016, 11:35 AM   #220 (permalink)
Registered Users
 

Join Date: Jun 2015
Location: KC MO
Default

I am running the Talon 15 on 3s with 16T Align 250MX.

I've over-temped it at least a few times with back to back flying in around 30+C weather.

Never over-currented.
__________________
Keith - MSH Brain2 Beta Team
Synergy N556 | LOGO 480 XXtreme | T-REX 470LP | Blade Nano S2
FrSky Horus X10S Github Repository
https://kc3dprint.com - 3D Printing on Demand and 3D Printed RC Helicopter Parts and Upgrades
Number is online now        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in


Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © Website Acquisitions Inc. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

SEO by vBSEO 3.6.1