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Sep 12, 2021, 05:19 PM
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Discussion

swivel device


https://www.rcgroups.com/forums/show...e#post47806523

this is a cross-reference.
The objective is to operate a swash plate, with limited access above and below.
This device transfers pushrod motion out and forward by 46mm.
It is similar to rockers and double-end rings underneath the swash plate.

A source and name for the double-end rings would be good, too.
Has anyone seen an in-line swivel used in this way? What is it called, so I can find it?
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Sep 12, 2021, 07:52 PM
Flying helis since 1978
rotorist's Avatar
You are kidding, right ??????


Sep 12, 2021, 08:19 PM
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Quote:
Originally Posted by rotorist
You are kidding, right ??????


Some designs use rocker and double-rings.
This does the same thing- it does use more pieces.

The rocker units are on 550+ sized copters- looks like a version of the bell HU-1.

There is a picture on one of the heli threads.
I now believe it is called a trunnion joint.

- that is also the name of the servo pushrod ends- why the same name for 2 different things?
A steering front wheel works in the same way.
Sep 12, 2021, 09:55 PM
CŠ bhfuil MicheŠl?
spykez's Avatar
Mate, please consider visiting your doc with my concerns.

You won’t want to. I get that. But you might thank me later.
Sep 13, 2021, 02:12 AM
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Quote:
Originally Posted by spykez
Mate, please consider visiting your doc with my concerns.

You wonít want to. I get that. But you might thank me later.
You are some kind of mental health professional?

Why does my rocker design elicit your concerns?

It is perfectly legitimate.

I have ideas on revising it to use a central top ball pivot, and reduce the number of parts.
I just piled a heap of components together to obtain the correct restraining conditions.
The use of ball-races is to reduce slop and make side restraint easier.

I can glue the inner and outer rings in place. I have done this before-Don't use the really runny CA-
it wicks inside the bearing- it gets crushed up, but is a bit gritty.
I have had some seized bearings which I managed to free up.

Freeing up doesn't work on Needle hinges, though (a different model) - use lots of 3-in-one oil, several applications if needed.


The only other unusual point is creating sub-threads in different areas.
I believe they have different audiences.
Not everybody follows every single forum and model build thread.

You may see I don't directly address your comments, which may be a "sign", but I got side-tracked here justifying my design.

The "sign" may be of scattered thinking processes, but there is no underlying medication shortfall causing the symptoms-
at least not to a clinical level.

I think my overall goal-seeking and goal-fulfilment activity is still working OK.

My underlying condition has been diagnosed and treated as "Depression".

Symptoms were excessive anxiety and reduced thinking and communication capability, tendency to sleep more,
getting a "cold chill" easily.

Having minor symptoms of several other disorders is not a cause for concern.
Some may be a rebound side effect of the medication.
Sep 13, 2021, 05:22 AM
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ref for new layout.
https://www.rcgroups.com/forums/show...5#post47808979
Sep 13, 2021, 08:39 AM
RBW's sock puppet account.
RaisedByWolves's Avatar
Quote:
Originally Posted by spykez
Mate, please consider visiting your doc with my concerns.

You wonít want to. I get that. But you might thank me later.
Iíve read your posts on this and while I can see where youíre coming from, Iím a lot like Owen.


Davinci, Galileo, Tesla, all great men plagued with erratic thought processes who managed the condition and made it work for them.

Iím betting Owen, much like me has trouble getting to sleep with racing thoughts and inventions going through his head.

For me last night was a renewed interest in my 3D printer that I hadnít touched in two years.

Needed a tail fin for a 130x, which I printed a couple of until I got good results, then it was off to find files for my newest obsession, the E160.

I found files to print out E160 tail fins and had to get up at midnight to go print one off so I could stop thinking about it.

Itís not fun at times, but itís not a bad problem to have either in some ways.
Sep 13, 2021, 10:20 AM
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Cyclone 7's Avatar
I am all for anything that keeps people busy, happy and out of trouble
Sep 13, 2021, 04:16 PM
Flying helis since 1978
rotorist's Avatar
The reason I asked if you were kidding is the picture of that monstrosity has at least seven points of failure/ potential slop.
Helicopters require fine motor control inputs to even keep them hovering.
Every joint, bearing point, linkage connection must be absolutely immaculate or you will be chasing that thing all over gods creation.
The least number of pivot points, the better.

You are not building a self stabilizing multirotor. Helicopters are inherently the most unstable creations ever invented. Your linkage pictures are way over complicated.

I do not know your skill level of flying. If you have never attempted to fly even a trainer type helicopter, I suggest getting a simulator and try to get a pre programmed model in the air.
I would bet money that you will have trouble.

Again my two Euros.

rotorist.
Sep 13, 2021, 05:08 PM
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Thread OP
Quote:
Originally Posted by rotorist
The reason I asked if you were kidding is the picture of that monstrosity has at least seven points of failure/ potential slop.
Helicopters require fine motor control inputs to even keep them hovering.
Every joint, bearing point, linkage connection must be absolutely immaculate or you will be chasing that thing all over gods creation.
The least number of pivot points, the better.

You are not building a self stabilizing multirotor. Helicopters are inherently the most unstable creations ever invented. Your linkage pictures are way over complicated.

I do not know your skill level of flying. If you have never attempted to fly even a trainer type helicopter, I suggest getting a simulator and try to get a pre programmed model in the air.
I would bet money that you will have trouble.

Again my two Euros.

rotorist.
1) See the revised version. 2 less joints.
2) There should be very little slop in this system.
Radial clearance in ballraces is quite small.

Sideways stiffness of the center stand may need beefing up,

I think the stiction levels in the ring-and-ball connectors is quite low.
You can get coated aluminium balls which have even less friction.

3) I am planning on having a lot of gyro assist.

The Multiwii control software will need a bit of feedback tuning.

Probably initial hover tests should be done with long ground arms, to prevent rotor strike.

4) There are a lot of other links and axles with arms involved.
I have not drawn then all up yet.

All will be fully tested on the ground for accurate motion, and sufficient servo torque.
I may have to go up a few sizes with the servos.
They are 2bb, metal gear units, but only mg90 sized.- maybe 2.5 kgf-cm.

5) I have seen videos of people trying to fly helicopters without knowing what they are doing, and promptly tipping them over.
I will get a specifically helicopter sim, to try out.
Sep 13, 2021, 07:34 PM
Flying helis since 1978
rotorist's Avatar
https://rc.runryder.com/t787277p1/
Sep 13, 2021, 08:48 PM
Registered User
both are being very carefully flown by folks who must have had years of rc helicopter experience and it looks like they have had more than a few self-midairs with the rotors and are being careful not to have more by not subjecting the rotors to abrupt forces, something no raw beginner is able to do

takes years and countless hours flying easier types, the flight reminds me of dragonflies and man-powered aircraft, beautifully delicate

2x Giant Kaman K-Max Rotex double Rotor R/C turbine Helicopter without Tailrotor (8 min 16 sec)
Sep 14, 2021, 03:33 AM
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Quote:
Originally Posted by rotorist
I will have a read.
Sep 14, 2021, 03:43 AM
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Thread OP
Quote:
Originally Posted by Pile It
both are being very carefully flown by folks who must have had years of rc helicopter experience and it looks like they have had more than a few self-midairs with the rotors and are being careful not to have more by not subjecting the rotors to abrupt forces, something no raw beginner is able to do

takes years and countless hours flying easier types, the flight reminds me of dragonflies and man-powered aircraft, beautifully delicate

https://www.youtube.com/watch?v=dfG7GEopWYk&t=283s
what do you mean, self-midairs?

The rotors are quite well apart where they cross over, and 450- size blades are very stiff, with no springing.
The 700-size blade may be more flexible.

Cross-over is at the 45 degree angles.

I think with mine , at 3500 + rpm, you may not be able to see the blades at all.
that is 58 rotations per second!- a slight flickering effect...
Sep 14, 2021, 05:34 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Did not know this, from
Kaman_K-MAX#Development (Wikipedia)

Quote:
Originally Posted by wikipedia
... The K-MAX relies on two primary advantages of synchropters over conventional helicopters: The increased efficiency compared to conventional rotor-lift technology; and the synchropter's natural tendency to hover. This increases stability, especially for precision work in placing suspended loads. At the same time, the synchropter is more responsive to pilot control inputs, making it possible to easily swing a load, or to scatter seed, chemicals, or water over a larger area. ...

Vriendelijke groeten Ron
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