RunRyder RC
WATCH
 1 page 1470 views POST REPLY
HomeContestAircraftHelicopterAerobatic 3D Contest › What makes a good 3D machine. Engineers out there?
02-04-2008 01:06 PM  10 years agoPost 1
devin120

rrVeteran

Canada

My Posts: All  Forum  Topic

Im sure theres alot out who are who look over a heli and say, why dont you do this or that. I was wondering for the sake of it, if you guys out there with a good engineering background or a good foundation of physics, what is it that would make a .90 size or any heli for that fact more snappy. What made me start this thread is a video of bobby watts and his stratus. Iv been looking, and right now id buy the BW stratus. Ive never seen anything snappier.... But what could make it snappier? Are we being confined by power right now? bogging down on maneuvers?

To me, obviously weight is a MAJOR factor, but i look at alot of 90's and they seem very tall, wouldn't roll increase if you could get that things is small as possible from top to bottom getting it to rotate around a tighter CG? Once again, i have no foundation of engineer and i thought some of you would like to help out and let me know what are the restricting factors that make all helis fairly the same.(aesthetically at least)

Are we at the peak performance and physical shape of the 3D competition model heli and mechanics setup?

Have fun with this. I'm looking forward to some good conversation.

Also could someone correct me but MA stratus are saying on their site they have the lightest 90 around? True?

PM  EMAIL  GALLERY  Attn:RR  Quote
02-10-2008 01:19 AM  10 years agoPost 2
Yug

rrMaster

UK. Herts

My Posts: All  Forum  Topic

A good 3D heli is one that is not overly heavy, rigid frames so control inputs are precise and don't suffer from flexing or slop, and it offers predictable response to given inputs. However most modern helis are pretty good provided they are setup well. Obviously having a bigger disc to mass ratio is better so as to achieve more axial rolls etc, but now with the advent of helis like the trex 600, this class is now just about as light as it can get 3.2Kg is very hard to better. Same can be said for 90 size where the 4.7Kg is about as good as it gets. Along with weight reductions, manufacturers are also taking the obvious step of keeping the battery mounting high to keep the CG up for better axial rolls etc.
Much of heli design is a materials issue where one should use the correct materials for the job in hand; CF where strength and stiffness is required, plastic where some flexability is useful in absorbing vibration and aluminium alloy for making inflexaible, light and strong components. These are becoming well understood.
New developments in flybarless systems is having a substantial impact on the 3D heli scene, with it's advantages of simplified mechanics (& consequent weight saving) and removal of the power required to drive the flybar system which can be upto 25%.
Another area that manufacturers are beginning to recognise are the design of tail grips which incorporate chinese weights. These dramatically reduce the tail pushrod forces and hence workload experienced by the tail servo, so it can perform with greater ease.
Most manufactureres now recognise the advantages of eCCPM and so have concentrated in developing helis offering good geometry, mechanical simplicity and the frame design to appropriately maintain accurate mechanical linkage from the servo to the swash. Thankfully, servo manufacturers are responding well with the new requirements with the introduction of servos such as the 8717s. Equally, due to the power requirements of these, this is being reflected in the available batteries, regulators, connectors and heavy duty cables.

Vegetable rights and Peace

PM  EMAIL  GALLERY  Attn:RR  Quote
06-05-2008 07:19 PM  10 years agoPost 3
w.pasman

rrElite Veteran

Netherlands

My Posts: All  Forum  Topic

wouldn't roll increase if you could get that things is small as possible from top to bottom getting it to rotate around a tighter CG?
Yes smaller can roll much faster. But smaller are very bad at doing large figures and more wind sensitive so it's a trade-off.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
06-05-2008 08:01 PM  10 years agoPost 4
wlfk

rrVeteran

uk

My Posts: All  Forum  Topic

3.2Kg is very hard to better.
Hmmm. I could get my logo 600 well below 3 if I went for the standard T-Rex 600 battery option.

Just stirring.

K

A bit like a kite, but 500 times more expensive

PM  EMAIL  Attn:RR  Quote
WATCH
 1 page 1470 views POST REPLY
HomeContestAircraftHelicopterAerobatic 3D Contest › What makes a good 3D machine. Engineers out there?
 Print TOPIC  Make Suggestion 

 3  Topic Subscribe

Wednesday, December 19 - 3:18 am - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

The RC discussion world needs to consolidate. RR is now one choice for that. Its software is cutting edge. It hosts on-topic advertising. Help RR increase traffic buy making suggestions, posting in RR's new areas (sites) and by spreading the word.

The RunRyder Difference

• Category system to allow Rep/Vendor postings.
• Classifieds with sold (hidden) category.
• Classifieds with separate view new.
• Answer PMs offsite via email reply.
• Member gallery photos with advanced scripting.
• Gallery photo viewer integrated into postings.
• Highly refined search with advanced back end.
• Hosts its own high end fast response servers.
• Hosts thousands of HD event coverage videos.
• Rewrote entire code base with latest technology.
• No off-topic (annoying) click bait advertising.
Login Here
 New Subscriptions 
 Buddies Online