HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 19, 2012, 01:48 PM
Registered User
Joined Oct 2012
14 Posts
Quote:
Originally Posted by BThirsk View Post
It might. At 8gms, you could run several in parallel.
What is the power requirement for the RX and Camera.
The heli runs at 7.4v.
Both the camera and transmitter I've spotted here both run at 12v.
The camera is 8g, the transmitter is about 30g (without the casing).
solarcow is offline Find More Posts by solarcow
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 19, 2012, 01:52 PM
Fly Fast, Fly Hard, Fly Fun
rexless's Avatar
Canada, BC
Joined Apr 2012
1,370 Posts
It's a nice day, no wind. My new blades arrived early. I'm lying in bed sick... go figure.

I was thinking about how wobbly the F45 can be and was wondering what causes this behavior. Is it the play from the links between the fly bar, swash plate and servos?
rexless is offline Find More Posts by rexless
RCG Plus Member
Old Oct 19, 2012, 02:19 PM
Brent 黑雁
BThirsk's Avatar
Canada, AB, Ponoka
Joined Jan 2012
1,711 Posts
Quote:
Originally Posted by rexless View Post
It's a nice day, no wind. My new blades arrived early. I'm lying in bed sick... go figure.

I was thinking about how wobbly the F45 can be and was wondering what causes this behavior. Is it the play from the links between the fly bar, swash plate and servos?
I personally think it is the flybar bobbing a little up and down trying to find the point 90 degrees to the main shaft.
That is one of the things I have noticed is different with my new flybar.
The wings do not want to change position and are more stable in their own flight path, so if they are pushed 10 degrees off the plain that is 90 degrees to the main shaft, they will slowly return to the 90 degree plain instead of bouncing back and forth. In theory, because they are the same total weight as the original flybar weights, the should react the same. This is the only explanation I have for why they are some much different.
Although the stock fkybar makes this heli extremely stable at lower speeds, I think it is what creates issues at high speed with the heli becoming unstable and lack or response.
BThirsk is offline Find More Posts by BThirsk
Reply With Quote
Old Oct 19, 2012, 02:33 PM
Registered User
The Netherlands, UT, Nieuwegein
Joined Sep 2012
78 Posts
Quote:
Originally Posted by BThirsk View Post
I personally think it is the flybar bobbing a little up and down trying to find the point 90 degrees to the main shaft.
That is one of the things I have noticed is different with my new flybar.
The wings do not want to change position and are more stable in their own flight path, so if they are pushed 10 degrees off the plain that is 90 degrees to the main shaft, they will slowly return to the 90 degree plain instead of bouncing back and forth. In theory, because they are the same total weight as the original flybar weights, the should react the same. This is the only explanation I have for why they are some much different.
Although the stock fkybar makes this heli extremely stable at lower speeds, I think it is what creates issues at high speed with the heli becoming unstable and lack or response.
I still hope MJX will make a new F45 flybarless but now i see the F47 is allso with flybar i am not sure anymore...
eminemin is offline Find More Posts by eminemin
Reply With Quote
Old Oct 19, 2012, 03:18 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
542 Posts
Interesting that others find problems with 'bouncing' in flight.
I thought that this was just due to some of my more extreme mods, but still was hesitant to personally recommend the F45 to Solarcow for FPV because of this. For anything else, the F45 is tops.
But in view of previous experience with the F39 (very stable as a camera platform in very LIGHT winds) and now the Trex 450 (sits like a rock in attitude, though trying to dash off without constant attention like all flybar CP) - just don't know.
I guess BThirsk may have hit the nail on the head. Alas, no real solution suggests itself.

Rexless - Get better soon!
OldOz is offline Find More Posts by OldOz
RCG Plus Member
Old Oct 19, 2012, 03:41 PM
Cranky old fart
Balr14's Avatar
Germantown, WI.
Joined Oct 2007
20,743 Posts
The bobbing of the flybar is simple air resistance against those round weights. That head design was meant for 7" helis that weigh 2oz. Scaling it up to 2 feet will have undesirable side effects. Using paddles instead of weights gives the flybar a lot more authority to resist change in it's plane of rotation. Regardless of weights or paddles, it doesn't want to change. All objects will resist changes in their plane of rotation; that's simple physics you can easily verify. The 45 flybar follows the head in gyroscopic precession and lags the swashplate movement by a lot. So it's always late and reduces head movement by up to 50% for every rotation.

Imagine you and your brother are Siamese twins and you share a leg. You are walking down the street and decide to turn left, but your brother doesn't know it and keeps going straight. That should give you a basic idea of the principles involved.
Balr14 is online now Find More Posts by Balr14
Reply With Quote
Old Oct 19, 2012, 04:02 PM
Different fly 4 different guy
gordonzo's Avatar
Canada, BC, Salmon Arm
Joined Jan 2011
1,892 Posts
Quote:
Originally Posted by Balr14 View Post
. . . Imagine you and your brother are Siamese twins and you share a leg. You are walking down the street and decide to turn left, but your brother doesn't know it and keeps going straight. That should give you a basic idea of the principles involved. . .
I have to admit - that is a pretty good analogy of how the stock F45 handles.

My mostly stock F45 does not have the bobbing effect but when I tried HBFP blades, the head speed went up, handling improved, flight times dropped, and significant bobbing came with it.

But I always thought the sliding effect was simply a combination of slow head speed and momentum?

regards . . . g
gordonzo is offline Find More Posts by gordonzo
Reply With Quote
Old Oct 19, 2012, 04:04 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
542 Posts
If I understand then, Balr14, the problems are rather those of scale, and may have no solution short of FBL?
Understandable, as - after all - the F45 was designed as a 'toy', and easy intro to the world of FP: and not really for the heavy modding we're carrying out on this thread. Reminds me of my valiant efforts to improve the F39 with the addition of a tail rotor - a good try, but simply wasn't going to get me where I wanted to go.
Still, within its job description, feel the F45 has to be the best value for money out there.
OldOz is offline Find More Posts by OldOz
RCG Plus Member
Old Oct 19, 2012, 04:14 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
542 Posts
Gordonzo -
See you're online!
In answer to your earlier question, the 30g nose weight is to ensure I can get the heli nose DOWN in the fairly high prevailing winds in my area. Sadly, some months ago had to watch an F45 drift out of sight (despite everything I could do) in a strong gust/ updraft.
Hasn't happened since.
Regards
John.
PS - I remember your own first open field crash - my experience was the reverse. I guess these helis do vary a lot (as we've noted).
OldOz is offline Find More Posts by OldOz
RCG Plus Member
Old Oct 19, 2012, 04:30 PM
Registered User
The Netherlands, UT, Nieuwegein
Joined Sep 2012
78 Posts
Quote:
Originally Posted by Balr14 View Post
The bobbing of the flybar is simple air resistance against those round weights. That head design was meant for 7" helis that weigh 2oz. Scaling it up to 2 feet will have undesirable side effects. Using paddles instead of weights gives the flybar a lot more authority to resist change in it's plane of rotation. Regardless of weights or paddles, it doesn't want to change. All objects will resist changes in their plane of rotation; that's simple physics you can easily verify. The 45 flybar follows the head in gyroscopic precession and lags the swashplate movement by a lot. So it's always late and reduces head movement by up to 50% for every rotation.

Imagine you and your brother are Siamese twins and you share a leg. You are walking down the street and decide to turn left, but your brother doesn't know it and keeps going straight. That should give you a basic idea of the principles involved.
So in this sense the coaxial setup is in advance cause the opposite movements of the blades handle better changes in gravity.
eminemin is offline Find More Posts by eminemin
Reply With Quote
Old Oct 19, 2012, 04:36 PM
Brent 黑雁
BThirsk's Avatar
Canada, AB, Ponoka
Joined Jan 2012
1,711 Posts
Quote:
Originally Posted by Balr14 View Post
The bobbing of the flybar is simple air resistance against those round weights. That head design was meant for 7" helis that weigh 2oz. Scaling it up to 2 feet will have undesirable side effects. Using paddles instead of weights gives the flybar a lot more authority to resist change in it's plane of rotation. Regardless of weights or paddles, it doesn't want to change. All objects will resist changes in their plane of rotation; that's simple physics you can easily verify. The 45 flybar follows the head in gyroscopic precession and lags the swashplate movement by a lot. So it's always late and reduces head movement by up to 50% for every rotation.

Imagine you and your brother are Siamese twins and you share a leg. You are walking down the street and decide to turn left, but your brother doesn't know it and keeps going straight. That should give you a basic idea of the principles involved.
I am a little confused. I though gyroscopic precession was the process of where the force(pitch) was applied related to where it actually affects flight as in if your forward elevator force was created at the extreme right point fo the rotor disc travel, the actual force would be exterted 90 degrees later, at the rear of the heli causing you to move forward.

Quote:
Originally Posted by OldOz
If I understand then, Balr14, the problems are rather those of scale, and may have no solution short of FBL?
Understandable, as - after all - the F45 was designed as a 'toy', and easy intro to the world of FP: and not really for the heavy modding we're carrying out on this thread. Reminds me of my valiant efforts to improve the F39 with the addition of a tail rotor - a good try, but simply wasn't going to get me where I wanted to go.
Still, within its job description, feel the F45 has to be the best value for money out there.
That's not necessarily correct. Even though there is a difference between the 90 and 45 degree reaction on the pitch by the flybar, fixing the flybar bobbing and keeping it in the plain you moved it too by the swash plate creates a completely different effect.
Think of it like this. If you move the swash plate 9 degrees and it move the flybar 9 degrees, this is what creates the pictch on the proper place to cause you heli to move. The way it is now, you have pushed the flybar off it's desired plain which is 90 degrees to the main shaft caused by centrifical force. With only the weight, the flybar wants to return to that centre point at 90 degree as fast as possible. Paddles help to keep the flybar in the new plain you have moved it to which gives you the reaction you desire.
A good example is a flybar 450 heli. It has paddles and this reaction is very sharp. I know it has a 90 degree flybar and the F45 is 45 degree, but the main difference is the mechanical advantage the the range of movement the 90 degree exerts over the 45 degree flybar. If you have both, move the flybar by hand and what what it does.
As I said, I have only have my F45 out twice due to bad weather, but at 80% ELV/ALI settings, it is very close to the response as my 450 for normal flying. At full power, of course, the 450 will change drastically. I have no more sliding effect.
BThirsk is offline Find More Posts by BThirsk
Reply With Quote
Old Oct 19, 2012, 04:48 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
542 Posts
An awful lot to think about in your post, BThirsk!
But thanks to your picture of the modded F45 flybar, decided to put weights on my Trex 450 paddles (it didn't come with any).
Reduced the heli from a real challenge to a vaguely cantankerous F45 (in normal mode). Getting there!
OldOz is offline Find More Posts by OldOz
RCG Plus Member
Old Oct 19, 2012, 05:06 PM
Brent 黑雁
BThirsk's Avatar
Canada, AB, Ponoka
Joined Jan 2012
1,711 Posts
Quote:
Originally Posted by OldOz View Post
An awful lot to think about in your post, BThirsk!
But thanks to your picture of the modded F45 flybar, decided to put weights on my Trex 450 paddles (it didn't come with any).
Reduced the heli from a real challenge to a vaguely cantankerous F45 (in normal mode). Getting there!
I put 2 weights on my 450 to tame it a little. It is a piece of sh*t heli with poor servos and excessive slop in the head as well as the tail so it does not handle as well as I would like. I also added weights to my 250 and it is now also very manageable because of the extra weights and head and tail are all align CNC parts with no slop.
It gets hard to move from the 4 flybarless CP helis to flybar. The response and reaction on the flybarless is instant and it goes where you point it.
That has been my issue with the F45. I needed it to have similar response the the CP helis or quit flying it like I did with the DH9116 which I gave away.
BThirsk is offline Find More Posts by BThirsk
Reply With Quote
Old Oct 19, 2012, 06:17 PM
John
Australia, QLD, Brisbane
Joined Aug 2012
542 Posts
Original quote BThirsk -
Quote:
I put 2 weights on my 450 to tame it a little. It is a piece of sh*t heli with poor servos and excessive slop in the head as well as the tail so it does not handle as well as I would like. I also added weights to my 250 and it is now also very manageable because of the extra weights and head and tail are all align CNC parts with no slop.
It gets hard to move from the 4 flybarless CP helis to flybar. The response and reaction on the flybarless is instant and it goes where you point it.
That has been my issue with the F45. I needed it to have similar response the the CP helis or quit flying it like I did with the DH9116 which I gave away.
As you know, the Trex FB was a very kind thought, but not my first choice.
However, when the dust settles a bit - and when (and if) I get reasonably competent with this CP, what next?
I really like the 450 size. Can see it a long way off, and it does already seem pretty immune to the local wind. The choice would seem to be between the Blade 450X, and the Align 450 plus DFC.
I'm told the best would be the Align with the BeastX - but obviously an expensive road to travel.
Any input appreciated!

PS - Only crash so far has been as a result of a feathering shaft bolt coming adrift (no thread locker). Even Align RTF can goof! (or really, the motto is - check EVERYTHING). $30 repairs, F45 would have laughed at the 4' drop!
OldOz is offline Find More Posts by OldOz
RCG Plus Member
Old Oct 19, 2012, 09:09 PM
Registered User
Malaysia, Federal Territory of Kuala Lumpur, Kuala Lumpur
Joined Jul 2012
90 Posts
Quote:
Originally Posted by eminemin View Post
I still hope MJX will make a new F45 flybarless but now i see the F47 is allso with flybar i am not sure anymore...
Seems that nobody from MJX is listening to us here. I wish there is...
juang1430 is offline Find More Posts by juang1430
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion On self stabilising single-rotor helis (FP/CP) and comparison to quadcopters and coax LMF5000 Electric Heli Talk 10 Apr 13, 2014 02:59 PM
Discussion UAV systems Single Rotor vs Multi Rotor iskoos UAV - Unmanned Aerial Vehicles 2 Jan 06, 2012 10:51 PM
Question Upgrading from Co-Axial to FP Single Rotor Judo JoNny Electric Heli Talk 57 Sep 20, 2010 12:10 PM
Discussion Best FP single rotor 4 CH Heli? helinewbie617 Micro Helis 76 Oct 31, 2009 07:16 PM
For Sale will trade my orbiter coaxial for a fp or cp single rotor heli micro heli Aircraft - Electric - Helis (FS/W) 3 Sep 05, 2007 01:36 PM