Fixed Pitch 450 VOL 2…Featuring the Flybarless FP450

[retroman]

Jburg, Boy can I relate to the everytime I try to fly I break something. I have been fiddling with my completed 450fp mod for about 2 months and it seems like it is one thing after another. Kind of like frankenstiens monsters body parts falling off every time he terroizes a village. I can say a FP does not have much of a reputation for hovering anyway.
Well let me go awaken the monster and see if I can fry another servo.

[icecycler]

jburg, there is a solution for that. I just added a front antirotation bracket. I am also using a 90 deg swash. Check out the first picture of #571 of this thread, I did the same for my other 450FP and it tighten up the slack a bit more. It did help some.

Ice

[jburg]

Well I haven't crashed it to hard in the last few attempts to fly this thing. Before I zip it around I like to hover it to get a feel for how it responds. But in my last attempt I was able to take it up and put it down without a crash. Still seems sluggish to respond thus I tend to over correct. But it seems a little more stable (was hoping it would be like my other FPs and hover without much input). I have been working on the flybar to get it as loose as possible, that does seem to help. I have also been re-reading the original thread by HH and JC to find any clues. All the videos I watch this thing seems pretty stable, but maybe its just my inexperience with birds of this size. Its only money.....but it is frustrating.

[HELIHANKSTER]

Yes the first thing I notice when I built the FP450 was how sluggish the response was. For me this was the primary reason for doing the flybarless mod as there’s not much to be done to the stock FC head to increase response. Honestly I haven’t flown my FP450 in a while and it’s been ages since I had the flybar on, but I do remember removing both the long bolts that run through the ends of the flybar. If I remember right, the response was a little better with the bolts off. On a typical flybar head the flybar weights work by adding weight to the flybar which in turn increases the gyroscopic effect of the flybar and paddles when in motion. This means a much larger force is required to move the helicopter in any direction to overcome the gyroscopic effect. Adding weights to the flybar slows down the responsiveness of the helicopter, so removing the weighted bolts on the FC Auxiliary rotor (flybar) should in theory increase responsiveness. I know the FC rotor head is not a typical head designed but its worth trying.

[jburg]

My question is should this machine with the flybar hover hands free or almost? My MCPX even being a CP, will hover for a few secs without corrective inputs. I was thinking the bolts at the end of the flybar would add to the stability and make it hover on its own. Certainly can understand these would make it sluggish to quick stick commands. I figured once I learned to fly this one, then I would move on to trying your flybarless design.

[HELIHANKSTER]

Like I said, it’s been a long time since I had a flybar on my FP450...I don’t remember it being unstable. If its dialed in right, I don’t see why it wouldn’t hover hands free for a couple of seconds. I wish Hyd and Onguard were still around as they both ran flybar setups on their FP450s and could give better feed back. Their birds always looked smooth in their videos. Like you have already mention, maybe you have too much slop/play in your swash plate. Have you tried switching it out with a different one? You really can’t compare the McpX to the fixed pitch 450. Not only is the head speed higher on the Mcpx, it’s also running a 3axis setup.

Trust me, I know how frustrating it can be. Honestly I don’t want you spending anymore money because of me, but what you’re looking for is the flybarless version of this helicopter. I can only give you my experience with the fbl version. The response is way faster than the flybar version and in my opinion it’s also very stable.

I decide to get the dust off the green goblin and give it a spin around the yard. I tried once before to show some hands off flight and fail miserable…well this time was no different. Even though the video sucks, I still think it shows that the fbl version will hover hands off for a few seconds. Lately I’ve only been flying cp birds so was just rusty enough flying the FP450 to almost crash it into the flag pole. I’ll post the video later tonight when I get a chance.

[ame]http://www.youtube.com/watch?v=lWwO1jl8sxE[/ame]

[jburg]

Very much appreciate your responses HH. And thanks for the video. Even tho I'm a noobie at this, I should be able to hover this and I can't.....yet. I have the swash the JohnnyCat had found. The 90 degree. Swash itself seems solid, but since its only held in place by the Elev and Ail servo, the opposite side is floppy. As it sits on the table, me moving the flybar moves the swash up and down (the unpinned side). Also the blade grip (long piece on the head) also has some play. The Z-links and swash to flybar links are not tight either.....have some play in that connection (wire thru hole). What would happen if the unused balls on the swash (front Elv and opposite side Ail) where held in place? A linkage to a solid tie point.

[icecycler]

jburg
I added another anti rotation bracket trimed down to quiet down the swash. it works really well. You might want to try that.



hope this helps, keep practicing you'll get it.

Ice

[HELIHANKSTER]

Nice Ice
That’s a lot of shiny bling…good thinking on the front ARB.

[HELIHANKSTER]

Jburg, what radio do you have again? If it’s programmable why not give the 120 swash setup a try. There’s two ways to stop the swash from moving up and down. Set your pitch curve in all flight modes to 50-50-50-50-50 or go in to your swash menu and set pitch value to zero. Use servo reversing to change servo direction if needed.

[icecycler]

Thanks HH, Thats my latest FP450 Custom. The entire head has been redone, allot of custom made components, new aluminum base plate and custom tail drive gear assembly. Bumped her up to a 12 tooth drive "pulley". Tail sticks like it's in cow poddy.

Ice

[OnGuard]

I am still around.

My FP 450 is still going, with the only failure being a tail servo. The only characteristic I am not happy with is the tendency for it to pitch up in forward flight.

Here are my thoughts on the FP 450 built using just a T-Rex 450 clone kit and the Multiplex Funcopter head.

The Funcopter weighs alot more than the FP 450, some were around 500-700 grams more. This means the head speed on the FP 450 is way lower because it is so much more lighter than what the funcopter head was designed for. This lower head speed also means the tail speed is lower, much lower than what the t-Rex 450 tail was designed for. So low that it is just barely adequate and will blow out very easily with any aggressive flight.

So how do you increase the head speed on a fp helicopter. Either add weight which we don't want to do or reduce lift. The only way we can easily reduce lift on the FP 450 it to trim the Funcopters blades. There are posts and pictures in the FP 450 threads on how this was done.

With the trimmed blades the head speed and tail speed will increase. The cyclic authority will should also be better because of the increase in head speed. The tail authority will be better, but still probably not good enough.

To finish correcting the poor tail authority larger tail blades have to be used. We were using 68mm 450 tail blades from x-heli , but these don't seem to be available anymore. This leaves an unresolved problem for fixing the tail authority which I think is a must. I don't know what the answer is to the lack of 68mm 450 tail blades being available, but something may be able to be done with cut down 500 tail blades and larger mounting bolts or a sleeve in the 500 tail blades?

I think there is an advantage to using a pro or sport clone vs. a v2 clone. The pro and sport clones have larger swash plates than the v2. This is why I used a 450 sport clone

Unless a computer radio isn't available I would recommend using the 120 deg swash setup and a flat pitch curve. This seems to be the easiest to do because all you need are the the 3 servos for cyclic and results in a very slop free setup, vs. getting a 90 deg swash and going through the trouble of making some sort of solution for a complete anti-rotation setup.

Just build the Funcopter head as it comes out of the package, I don't think anything will be gained with trying to tweak it and get extreme free movement out of it. It will wear in on it own.

Don't forget when setting up the tail that the Funcopter head rotates counterclockwise vs. the normal clockwise for a CP 450.

Build the helicopter up and then work on getting the weight balance right. It should balance on the main shaft or be just a little nose heavy. I think I have 10-15 grams of weight in the nose of my canopy to get the balance right.

Radio setup I have 120 deg swash mix with flat pitch curve, linear throttle curve, no dual rates set, 25% expo on the cyclic and rudder, and 110% endpoints on the Cyclic. Adjust the swash link to get the helicopter to hover with as little input as possible. You will never get it perfect it will always be a little sticky and the swash will probably not be level when you are done trimming. You should be able to get it to hover hands off for a few seconds, but that's all you can expect. It will not self stabilize like a 45 deg flybar setup.

Use a motor and pinion combination that will hover at around 50-60% throttle. Around 3550kv on the motor and I think a 11 tooth pinion.

Watch the Finless build videos for the 450 Pro a lot of them are very help full and still apply to the FP 450.

To summarize I think the main thing to make the FP 450 build successful are trimming the main blades and getting larger tail blades.

[jburg]

I am tempted to try the 120 swash. I have a DX7 radio, so I can program it up. I might try Ice's idea of the double ARB first since I have a spare. Weather is getting better finally, time to get out there and take my lumps.

[HELIHANKSTER]

Originally Posted by OnGuard

I am still around.

My FP 450 is still going, with the only failure being a tail servo. The only characteristic I am not happy with is the tendency for it to pitch up in forward flight.

Here are my thoughts on the FP 450 built using just a T-Rex 450 clone kit and the Multiplex Funcopter head.

The Funcopter weighs alot more than the FP 450, some were around 500-700 grams more. This means the head speed on the FP 450 is way lower because it is so much more lighter than what the funcopter head was designed for. This lower head speed also means the tail speed is lower, much lower than what the t-Rex 450 tail was designed for. So low that it is just barely adequate and will blow out very easily with any aggressive flight.

So how do you increase the head speed on a fp helicopter. Either add weight which we don't want to do or reduce lift. The only way we can easily reduce lift on the FP 450 it to trim the Funcopters blades. There are posts and pictures in the FP 450 threads on how this was done.

With the trimmed blades the head speed and tail speed will increase. The cyclic authority will should also be better because of the increase in head speed. The tail authority will be better, but still probably not good enough.

To finish correcting the poor tail authority larger tail blades have to be used. We were using 68mm 450 tail blades from x-heli , but these don't seem to be available anymore. This leaves an unresolved problem for fixing the tail authority which I think is a must. I don't know what the answer is to the lack of 68mm 450 tail blades being available, but something may be able to be done with cut down 500 tail blades and larger mounting bolts or a sleeve in the 500 tail blades?

I think there is an advantage to using a pro or sport clone vs. a v2 clone. The pro and sport clones have larger swash plates than the v2. This is why I used a 450 sport clone

Unless a computer radio isn't available I would recommend using the 120 deg swash setup and a flat pitch curve. This seems to be the easiest to do because all you need are the the 3 servos for cyclic and results in a very slop free setup, vs. getting a 90 deg swash and going through the trouble of making some sort of solution for a complete anti-rotation setup.

Just build the Funcopter head as it comes out of the package, I don't think anything will be gained with trying to tweak it and get extreme free movement out of it. It will wear in on it own.

Don't forget when setting up the tail that the Funcopter head rotates counterclockwise vs. the normal clockwise for a CP 450.

Build the helicopter up and then work on getting the weight balance right. It should balance on the main shaft or be just a little nose heavy. I think I have 10-15 grams of weight in the nose of my canopy to get the balance right.

Radio setup I have 120 deg swash mix with flat pitch curve, linear throttle curve, no dual rates set, 25% expo on the cyclic and rudder, and 110% endpoints on the Cyclic. Adjust the swash link to get the helicopter to hover with as little input as possible. You will never get it perfect it will always be a little sticky and the swash will probably not be level when you are done trimming. You should be able to get it to hover hands off for a few seconds, but that's all you can expect. It will not self stabilize like a 45 deg flybar setup.

Use a motor and pinion combination that will hover at around 50-60% throttle. Around 3550kv on the motor and I think a 10 tooth pinion.

Watch the Finless build videos for the 450 Pro a lot of them are very help full and still apply to the FP 450.

To summarize I think the main thing to make the FP 450 build successful are trimming the main blades and getting larger tail blades.

Most excellent post my brother! Great run down and spot on.

Good to hear from you bud, hope you’re doing well.
It’s a bummer Xheli doesn’t carry the 68mm blades anymore. For me, I’ve worked around this issue by using the 480 Pro tail rotor set. It’s a little longer than the stock plastic rotor set, about 42mm bolt to bolt. It’s just long enough to get away with using stock V2 tail blades. Of coarse this is in conjunction with trimming the main blades.

http://www.infinity-hobby.com/main/p...oducts_id=7023

[icecycler]

HH, You can still get them from HK and cheep!

http://www.hobbyking.com/hobbyking/s...il_Blade_.html

I know the wait takes some time, thats the only disadvantage.

Ice

[jburg]

Originally Posted by HELIHANKSTER

Jburg, what radio do you have again? If it’s programmable why not give the 120 swash setup a try. There’s two ways to stop the swash from moving up and down. Set your pitch curve in all flight modes to 50-50-50-50-50 or go in to your swash menu and set pitch value to zero. Use servo reversing to change servo direction if needed.

HH, I decided to go the 120 deg swash route. I have the heli rebuilt and the head/swash setup is definitely more solid.......lot less slop. I have a DX7 TX, reprogrammed it for the 120 swash, set pitch to zero both on the swash page and the pitch page (50% across), but I have something strange going on that I can't figure out. When I actuate my Elev, I have some Aile movement. I have mixing inhibited, so I'm at a loss to what is causing that. I can also see it on my switch position screen....shows the movement of all channels. I have no servo movement with throttle (which is good).
I know you don't use Spektrum, but maybe you have run into this or there another freak that uses this system.
Thanks for any help.

[jburg]

I believe I figured out my issue with the Elev to Aile mixing......I changed from a 120 deg 3 server swash to a 90 deg 3 servo in the TX setup. Still works the same without the added mix. Hope this is what folks would be advising.

[jburg]

OK..success. She is airborne. Big difference the swash change made. Still have some tweaking today as it wants to tip as it gets light, but once in the air its fairly stable. Still need to get use to it.....but I'm feeling better now. Just a matter of dialing it in....
Thanks all!

[HELIHANKSTER]

Originally Posted by icecycler

HH, You can still get them from HK and cheep!

http://www.hobbyking.com/hobbyking/s...il_Blade_.html

I know the wait takes some time, thats the only disadvantage.

Ice

Sweet Ice, It’s good to know there’s still 68mm blades available. Next time I make a order with the King, will add a set to my order just to have.

[HELIHANKSTER]

@jburg
Ummm…that is strange. Neither running a flat pitch curve or reducing the pitch value in the swash menu to 0 should cause what you’re describing. No matter as it sound like you got it figured out…sweetness!