Shaft driven tail rotor repair help needed

[arquitron]

Hello fellow UFLYS pilots,

I had a crash with my UFLYS and wrecked the tail shaft, now the tail rotor does not spin. Does anyone have experience repairing this part? The shaft pinion that makes contact with the main rotor gear is bent All repairing tips are welcome.

Thx

[ERRATIC]

The shaft is made from carbon fiber, you will have to get a replacement for it is broken. Wow hobbies should have them is stock.

Just checked, they do.
http://www.wowhobbies.com/hm-ufly-z-...1-1-1-1-1.aspx

While your at it replace the pinion gear on the end of the shaft.
http://www.wowhobbies.com/hm-ufly-z-...1-1-1-1-1.aspx

Also check the boom for straightness, in a crash it is easily bent.

I however have made my own drive shafts on my lathe.from 3mm carbon rod i buy from a hobby store.

Some guys on the forum have made a simple slip shaft that helps solve the breakage problem. Perhaps one of them will chime in on this


Steve

[tkerins]

I solved my tail drive shaft issues with 2mm piano wire(steel). No more broken shafts anymore, ever! Did the clutch mod for the gear at the same time. So far so good.

And just FYI, anyone thinking they can't replace the shaft with steel because it will make an already tail heavy bird even worse.....it added less than 5 grams of weight to my tail and my balance was still perfect from the weight I already had installed in the canopy.
The hardest part was creating spacers for the bearings so they stay in place on the shaft.

[magicmarty]

Originally Posted by tkerins

I solved my tail drive shaft issues with 2mm piano wire(steel). No more broken shafts anymore, ever! Did the clutch mod for the gear at the same time. So far so good.

And just FYI, anyone thinking they can't replace the shaft with steel because it will make an already tail heavy bird even worse.....it added less than 5 grams of weight to my tail and my balance was still perfect from the weight I already had installed in the canopy.
The hardest part was creating spacers for the bearings so they stay in place on the shaft.

just curious when you say clutch mod for the gear are you talking about the gears on the rear ? i did a mod on mine to allow it to slip without stripping the front bevel gear off the main...a bit curious on how you did your clutch mod to see if its basically the same way i did mine...


thanks and happy flying....

[tkerins]

I thought about doing it the way you did yours. I got a 2mm collar but thought it would be too difficult to grind it down without throwing off the balance. Also that method requires putting pressure against the gear in the opposite direction of "mesh" with the mating gear.
What I did was took the final gear(on the metal shaft) off and replaced it with the other gear with the "D" hole. I ground out the "D" hole just enough to allow the gear to slip on the shaft and I had to sand down the collar that goes through the bearing so the "pin" in the metal rotor shaft rests at the same place as on the original gear. Some people mention removing the "pin" but doing that would allow the shaft to shift to the side under load. So now friction is the only thing transferring motion from the gear to the rotor shaft. This doesn't have the adjustment of your method but it looks completely stock and was quick and easy to do and didn't require any additional parts.

[tkerins]

Originally Posted by magicmarty

just curious when you say clutch mod for the gear are you talking about the gears on the rear ? i did a mod on mine to allow it to slip without stripping the front bevel gear off the main...a bit curious on how you did your clutch mod to see if its basically the same way i did mine...


thanks and happy flying....

Here are some pics of mine;
You can see the end of the new steel drive shaft on the rear tail gear.


Here you can see the front end of the steel drive shaft.


Here is my o-ring mod which saves the blades from breaking.

[tkerins]

Here is the strap keeping the stabilizer from moving too far since the glue won't hold.


I saw someone show this as a mod but wasn't sure why they did it. I did it to get clearance under the receiver so I could use the rubber bands to secure the battery.

[magicmarty]

Originally Posted by tkerins

I thought about doing it the way you did yours. I got a 2mm collar but thought it would be too difficult to grind it down without throwing off the balance. Also that method requires putting pressure against the gear in the opposite direction of "mesh" with the mating gear.
What I did was took the final gear(on the metal shaft) off and replaced it with the other gear with the "D" hole. I ground out the "D" hole just enough to allow the gear to slip on the shaft and I had to sand down the collar that goes through the bearing so the "pin" in the metal rotor shaft rests at the same place as on the original gear. Some people mention removing the "pin" but doing that would allow the shaft to shift to the side under load. So now friction is the only thing transferring motion from the gear to the rotor shaft. This doesn't have the adjustment of your method but it looks completely stock and was quick and easy to do and didn't require any additional parts.

Thanks for sharing it sounds nice, i might try it the way you did yours to compare the 2 and make a final decision on which i like best...mine has to checked often cause it sometimes it comes a little loose and slips a bit to easily...i have 3 extra gear sets so i have plenty to experiment with...

just a thought on how you sanded the collar down on the gear where it sits against the pin...what if instead of sanding it flat , sand it to where its just a tiny bit long and then take a small drill bit spinning and hold the gear against it on its side and put small humps for the pin to kind of lock into but under pressure it will slip to out , then reset back into a hump when the pressure resides...

[tkerins]

Originally Posted by magicmarty

Thanks for sharing it sounds nice, i might try it the way you did yours to compare the 2 and make a final decision on which i like best...mine has to checked often cause it sometimes it comes a little loose and slips a bit to easily...i have 3 extra gear sets so i have plenty to experiment with...

just a thought on how you sanded the collar down on the gear where it sits against the pin...what if instead of sanding it flat , sand it to where its just a tiny bit long and then take a small drill bit spinning and hold the gear against it on its side and put small humps for the pin to kind of lock into but under pressure it will slip to out , then reset back into a hump when the pressure resides...

I actually thought about doing exactly what you said. I was going to make grooves in the collar to allow the gear to grab a bit. I ended up not doing this for two reasons. One, it might grab too well and allow the gear to strip. Two, for it to work the gear has to be able to shift to the side to slip past the grooves and I really don't want the gear to move side to side causing "mesh" issues. I was concerned that my method of just reaming out the gear might allow it to slip too easy so I also lightly sanded the steel rotor shaft around the circumference where the gear rests. I sanded "lengthwise" on the shaft to create more friction against the gear. So far it does not appear to be too loose. It has not lost the tail under normal operation but then I don't know for sure if it will slip when it needs to either. I have had a couple of hard landings and thought for sure the gear would have stripped prior to the mod but no signs of it happening yet.

[magicmarty]

I took mine apart and did the mod like yours and i have to say i like yours better for a couple of reason...it looks like stock and on mine it sets the tail shaft and rotor out to the left about 2mm and it was causing the servo to bottom out cause the pitch balls on the tail rotor grips would close all the way and pinch the shaft...your way the shaft is in its original position....

what i did a bit different was i used the gear with the slot for the pin and sanded it down where there was only a little bit of the slot left, then i rounded the corners on the slot so the pin could slip out under pressure...when i put it back together it didn't take much pressure to get it to slip so i found another E clip that goes on the out side of the shaft and placed it between the original E clip and bearing to increase the tension and it feels good and snug but will slip when i hold the main gear and turn the tail rotor blades...i thought about the gear mesh slipping with the extra clip there but when i slipped it and watched it only the shaft moved out not the gear it stayed the same, i think cause the bearing is holding it nicely meshed with the outer boom gear...so if yours comes loose or you want to increase the tension a bit try placing a second E clip between the bearing and other clip...i used one from a rc car and gently squeezed it to fit nicely on the shaft...

I really appreciate you sharing your method of the gear clutch , soon as i get some decent weather i am looking forward to test flying it...

Have you did the flybar less conversion on your uflys ? it really is nice and a lot more stable and responsive with the Henge 922 servos....i turned up the ext on the rx a bit and last time i flew i did a back flip in forward flight it was very impressive...i know for sure it would have never did it with the flybar head on...

Thanks again and happy flying....

[magicmarty]

oh i forgot to mention i replaced the tiny pin that goes thru the shaft because it is not long enough...its only 2.7 mm so i made a new one at 2.99 mm and it fits perfect inside the bearing and makes full contact across the plastic collar on the gear...

[tkerins]

I bought a 20 pack of those e-clips so i'm set there. I checked me clutch yesterday and it definitely is slipping under load so I know it works. The next time I take it out I have to make sure it is not slipping too easily. Thats the only problem with this kind of mod is that it may get more loose as it is used. I don't know if I will try this but just FYI. One of the things others have done to keep the gear from turning too easily was to put Elmers glue on the shaft where the gear sits. I guess it creates the friction needed to keep the gear in place. They may just be putting it right where the gear meets the shaft, I'm not certain. This to has to be re-added every so often.

No flybarless for me yet. I wasn't too keen on the expense of all the things that need to be replaced. I would rather buy a different heli and sell my ufly. I thought about the bell-hiller mod though. That is inexpensive but I am concerned that it will get damaged by the blades in an impact. (it sits right in the "strike zone").
I am actually getting used to the response of it stock. I am starting some minor forward flight but need to go to a larger open area to practice more. I will wait until I have gotten much better with it before I make a determination of whether I like it stock or not. Hey, its more of a challenge this way.

[magicmarty]

when i did the flybar less conversion it cost me less the 20 dollars for the parts...accept for the upgraded servos they were like 10 each...i just took the 2 unused inner swash plate balls and placed them on the blade grips and used the stock uflys shaft and placed the v370 head on it , then all i needed was the v370 links and i shortened the uflys servo links cause the swash sets a little lower and it was finished...really easy to do conversion...

i read about the white glue being used for the clutch and its supposed to hold and break loose when the tail rotors strike something...if i see it is slipping perhaps i will give it a try just have to careful around the bearing i guess...

if yours gets loose you could try putting a extra clip to tighten it up as i did but its tuff to get in there cause you have to squeeze the plastic ends to make room for it to fit between the bearing and the stock clip...

to much wind and its stormy here today so i wont get to do any test flying today, but soon as i get the chance i will give it a good testing to see if the tail holds good...

thanks and good luck...

[tkerins]

To go flybarless, my understanding was that you also had to replace the reciever because the rx2435 is NOT a flybarless RX. I thought you had to change it to a flybarless compatible RX like the rx2437v? How does yours fly? I'm sure the rx2435 was not meant to compensate for no flybar.

[ERRATIC]

Just turn off the gyros on the 2435?

Steve

[tkerins]

Someone correct if if i'm wrong but if I have no flybar AND no gyro to compensate for a lack of a flybar, then I also have NO stability and would probably crash quickly.

[ERRATIC]

Good question. I don't know I fly a fly-bar with the aileron and elevator gyros off.

Steve

[magicmarty]

if yours is the uflys with the rx 2435 it has the 3 axis gyro needed for the flybar less setup..only the older ufly with the older rx that does not have the 3 axis will not support the flybar less head....mine flies better as flybar less and is more precise to stick inputs its like your thumb is directly attached to the head if that makes sense...

[magicmarty]

read thru this posting and it gives good info on doing the conversion , everybody that has did the conversion is running the rx 2435 and they all say it works great and is really stable...you could switch the rx but its not necessary cause the 2435 works flawless with the conversion...but i would never try to fly mine with the 3 axis turned off it would be very difficult...at first i had the wrong length link balls set on mine and switched it back and posted on there and they helped me get it set up the rite way and i love it ...

https://www.helifreak.com/showthread.php?t=277657