direct drive motor 450 pro cp / fp

[icecycler]

HH Everything that I have read shows that the urethane belts are the best as far as abrasion and strenght. check this out.

http://www.gatesmectrol.com/mectrol/...cation_id=5322

The question for you is how much tension do you have on the belt, Is it like a banjo string or is there some deflection between the pulleys? There will be some initial stretching, but once its done it should be good to go. Normal defection should be at least 1/64th per inch of span. thats the formula we use on our timing belts. Hope this helps.

Ice

[HELIHANKSTER]

Well, so here was my plan…with the new belt on, take a quick nothing fancy flight around this yard to show the belt-to-TT mod does work. Had a bad feeling something might go wrong so left the canopy off just in case…glad I did. Once in the air, right away I notice a tail kick that wasn’t present yesterday, but being me I keep flying away. After a little bit, I landed to adjust a few setting in the radio. At this time I should of keep the heli on the ground, but again being me…took back to the air. It wasn’t long after lift off that I hear something not right and tried to bring it in. Well this time I wasn’t fast enough and my poor stretched DD bird started spinning out of control. Man I hate the feeling of loosing control, but on a brighter side did manage to keep it of hitting the drive way…that would of done some serious damage. As you will see in the video the drive belt was completely sheared in half. Wasn’t expecting that at all…I guess the belt was so loose it jump the main pulley, but honestly I don’t know.

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


At the end of the day I only have me to blame. I got one free pass using the junk belt, so should of known I wasn’t going to get another. Anyways, it’s been fun messing around with the DD motor concept and I think JC did a excellent job making the frames, but I’m going to bow out for now and go back to the gear drive machines.

[HELIHANKSTER]

Originally Posted by icecycler

HH Everything that I have read shows that the urethane belts are the best as far as abrasion and strenght. check this out.

http://www.gatesmectrol.com/mectrol/...cation_id=5322

The question for you is how much tension do you have on the belt, Is it like a banjo string or is there some deflection between the pulleys? There will be some initial stretching, but once its done it should be good to go. Normal defection should be at least 1/64th per inch of span. thats the formula we use on our timing belts. Hope this helps.

Ice

Thanks for the information Ice
There was defection between the pulleys. On the first belt tension was set just right I think. On the second belt (smaller by one groove) it was a little tighter than I like, but still had some defection and there was no binding at all. I figured it would stretch out a little once I got a flight in and be just right for at least a flight or two. I think something is going on that I’m not seeing. Maybe at high rpm the belt is rubbing up against the frame. I tell ya, I’m still dumb founded over the second belt splitting in half. O well, if the urethane belt is the strongest then I would say the belt to TT mod is a epic fail…at least it was for me.

[icecycler]

Wow bummer HH. It did not take that long to shred that belt. It must have really been going through some stress periods to do that. Were there any tail tail signs of rubbing on the frame? How about alignment from pulley to pulley? Or maybe, there is just too much stress on that MXL belt. Overloaded. Still a bummer when you put all that work into something and #$% happens.

Ice

[hochoco]

Originally Posted by HELIHANKSTER

... Anyways, it’s been fun messing around with the DD motor concept and I think JC did a excellent job making the frames, but I’m going to bow out for now and go back to the gear drive machines.

Helihankster,

I'm sorry to learn about the unfortunate incident.
It was good to see when it was in the air. How was the tail authority with that setup?

Hopefully your creative juices will start flowing to have you back with some good ideas to fine-tune the design and make it work better :-)

Good luck and best regards,

HAROLD

[johnnycat500]

Man HH I know that feeling. That quad I built with the modded 450 frame did not work out. When you build from scratch it's an experiment. I think the dd450 frame is best as a fp sport flyer . If someone wants to get really crazy you need the geared stock setup. The dd 450 cp I have ,I am going to put the fc head back on it and just keep it fp. Looking forward to seeing your next build with that new FBL setup you have.

[HELIHANKSTER]

First off I want to tell you guys how much I appreciate the support. Knowing you guys have been there and know what it’s like really mean something to me.

Originally Posted by icecycler

Wow bummer HH. It did not take that long to shred that belt. It must have really been going through some stress periods to do that. Were there any tail tail signs of rubbing on the frame? How about alignment from pulley to pulley? Or maybe, there is just too much stress on that MXL belt. Overloaded. Still a bummer when you put all that work into something and #$% happens.

Ice

I didn’t see any signs of rubbing on the frame, but the alignment between pulleys wasn’t perfect. I couldn’t get the pulley attached to the boom mount TT drive shaft any lower so the belt was touching the top flange of the drive pulley. I didn’t think this touching would affect the belt so much, but maybe at high speed it does. Do you think this could have been my problem?

Originally Posted by hochoco

Helihankster,

I'm sorry to learn about the unfortunate incident.
It was good to see when it was in the air. How was the tail authority with that setup?

Hopefully your creative juices will start flowing to have you back with some good ideas to fine-tune the design and make it work better :-)

Good luck and best regards,

HAROLD

Tail authority was real good on the first few flights as far as I could tell. I was able to do hard pitch pumps and turns with no problems. Even yesterdays with the mysterious tail kick ( which I’m sure was belt related) the tail over all was holding well. I have read that you can loose up to 10% efficiency running the tail blades down into the rotor wash and this may be true, but I saw no negative effects. Which makes me a believer that the tails blades can successfully run either way.

The juices are already flowing my friend, check the bottom of this post. I can’t stop even if I tried

Originally Posted by johnnycat500

Man HH I know that feeling. That quad I built with the modded 450 frame did not work out. When you build from scratch it's an experiment. I think the dd450 frame is best as a fp sport flyer . If someone wants to get really crazy you need the geared stock setup. The dd 450 cp I have ,I am going to put the fc head back on it and just keep it fp. Looking forward to seeing your next build with that new FBL setup you have.

Sorry to hear the 450 frame quad didn’t work out. I really liked the looks of it and how unique it was. I think as tinkers we live for the experiments, especially when the experiment work…just hard to remember that when it doesn’t. Totally agree with you bud, I had zero issues with my dd fp450 and just yesterday after the crash my first thought was…screw it, I’m putting this bird back together as a fixed pitch and be done with it. But after I cool down I started thinking…with my luck these days with aftermarket belts what could I do to eliminate belts all together and still use the DD motor and frames as a cp helicopter. Then bang, out of nowhere it hits me! What if I replace the main tail drive pulley with the stock Pro anti-rotation drive gear. I’m already using the stock Pro boom mount, so should just need to swap out the modified TT tail drive gear with a stock one that has the lower gear on it. So last night with this idea in my head, I completely tore down the crashed bird and cut the side frames to accommodate the anti-rotation gear. Then did a quick test fit (it was getting past my bed time) and spin up to see if all was good. Here’s a couple of pictures, hopefully I will get a chance to put the bird back together in the next couple of days as I think this setup might just be a winner for me.

[icecycler]

HH, with the pulleys misaligned, and being that the both pulleys being so close to each other didn't help the cause. If the centers were 5 inches apart it could have been tolerable, but on these birds thats impossible. I think when you got the tail kick, the belt actually rode up on the pulley flange and the inital damage was done. Then it might have done it again on the second flight and thats when it shredded the belt. Through my experiences i've seen larger timing belts shred like that, the most common cause is a jammed up pulley, otherwise it's from misalignment, now mind you this scenrio is over time, only because the my applications are not spinning that fast. Still an bummer man, but knowing you, the gears are turning for your next ideas already.

Ice

[hochoco]

Originally Posted by HELIHANKSTER

First off I want to tell you guys how much I appreciate the support. Knowing you guys have been there and know what it’s like really mean something to me.
...
The juices are already flowing my friend, check the bottom of this post. I can’t stop even if I tried

... Then bang, out of nowhere it hits me! What if I replace the main tail drive pulley with the stock Pro anti-rotation drive gear. I’m already using the stock Pro boom mount, so should just need to swap out the modified TT tail drive gear with a stock one that has the lower gear on it. So last night with this idea in my head, I completely tore down the crashed bird and cut the side frames to accommodate the anti-rotation gear. Then did a quick test fit (it was getting past my bed time) and spin up to see if all was good. Here’s a couple of pictures, hopefully I will get a chance to put the bird back together in the next couple of days as I think this setup might just be a winner for me.

Another excellent idea! Ingenuity at work :-)
Did you have to drill a hole in the main shaft to accomodate the the anti-rotation gear?

Looking forward to your test flight. I have high confidence that it will work well this time.
Thanks for sharing.

HAROLD

[johnnycat500]

I knew it would not take you long to have another brain storm . This is pure genius HH.Now you will get the tail RPM you want.

[HELIHANKSTER]

Originally Posted by icecycler

HH, with the pulleys misaligned, and being that the both pulleys being so close to each other didn't help the cause. If the centers were 5 inches apart it could have been tolerable, but on these birds thats impossible. I think when you got the tail kick, the belt actually rode up on the pulley flange and the inital damage was done. Then it might have done it again on the second flight and thats when it shredded the belt. Through my experiences i've seen larger timing belts shred like that, the most common cause is a jammed up pulley, otherwise it's from misalignment, now mind you this scenrio is over time, only because the my applications are not spinning that fast. Still an bummer man, but knowing you, the gears are turning for your next ideas already.

Ice

I think you are right on the money with the belt riding the flange scenario Ice. So for future reference do you think 5inches center to center at this high of rpm is the safest minimal distance one should go, or do you think I could get away with say 4inches. I’m just bouncing this information around in my head a little. Has Harold did with his extensions, I see no reason why the boom mount location only on the DD frame could be move back a couple of inches. With the boom mount extended back and with the use of idler pulleys, I definitely think 4inches center to center is doable. And has Harold pointed out, having the frame itself extended back there’s no need for a special length boom, belt or TT shaft to get the distance needed to run longer blades.

[HELIHANKSTER]

Originally Posted by hochoco

Another excellent idea! Ingenuity at work :-)
Did you have to drill a hole in the main shaft to accomodate the the anti-rotation gear?

Looking forward to your test flight. I have high confidence that it will work well this time.
Thanks for sharing.

HAROLD

Using a solid Esky King 2 shaft on this bird that has the pulley hole pre-drilled so I was good to go. I also think the Beam and Black Angel shafts that have the pulley hole pre-drilled will work also if using the DFC flybarless style head .

[HELIHANKSTER]

Originally Posted by johnnycat500

I knew it would not take you long to have another brain storm . This is pure genius HH.Now you will get the tail RPM you want.

Yeah Brother I think this setup might be the ticket. I know it’s going back to the land of gears, which none of us wanted, but I hoping this setup allows me to run 4 and 5s with no tail issues.

[icecycler]

Originally Posted by HELIHANKSTER

I think you are right on the money with the belt riding the flange scenario Ice. So for future reference do you think 5inches center to center at this high of rpm is the safest minimal distance one should go, or do you think I could get away with say 4inches. I’m just bouncing this information around in my head a little. Has Harold did with his extensions, I see no reason why the boom mount location only on the DD frame could be move back a couple of inches. With the boom mount extended back and with the use of idler pulleys, I definitely think 4inches center to center is doable. And has Harold pointed out, having the frame itself extended back there’s no need for a special length boom, belt or TT shaft to get the distance needed to run longer blades.

HH, The longer the distance between centers is a plus. But 4" could be doable also. As long as belt covers at least half the pulley diameter. The more critical part of the build is to make sure the pulleys are parallel to eachother and on the same plane so there is less risk of the belt trying to climb up onto the flange.With the MXL belt, even a 16th out will cause enough havac that could be catostrophic.

Ice

[HELIHANKSTER]

Originally Posted by icecycler

HH, The longer the distance between centers is a plus. But 4" could be doable also. As long as belt covers at least half the pulley diameter. The more critical part of the build is to make sure the pulleys are parallel to eachother and on the same plane so there is less risk of the belt trying to climb up onto the flange.With the MXL belt, even a 16th out will cause enough havac that could be catostrophic.

Ice

Okay I know I keep reducing the length on you, but do you think 3 ¼ +/- inches will be enough for the belt to cover half the pulleys? This would give me enough clearance to run 360mm blades with the stock Pro boom length. Wouldn’t want to go crazy extending the frame if I don’t have to. If I was to try a belt setup again, this configuration is what I would try.

[icecycler]

HH, the two idlers are going to give it the contact on the driven pulley if you keep them close to the outside diameter of the driven pulley, maybe 1 inch on centers if you can. The other benefit that the idlers will do is to help track the belt better also. For the entire assembly to work properly you have to have every pulley / idler on the same plane, no twists, no nothing. Lay a straight edge on the top of the big pulley and line everything up to that. If you can spool it up on a test stand and watch the belt track, you should be good to go. I think you'll have the winning ticket there man.

Ice

[HELIHANKSTER]

Originally Posted by icecycler

HH, the two idlers are going to give it the contact on the driven pulley if you keep them close to the outside diameter of the driven pulley, maybe 1 inch on centers if you can. The other benefit that the idlers will do is to help track the belt better also. For the entire assembly to work properly you have to have every pulley / idler on the same plane, no twists, no nothing. Lay a straight edge on the top of the big pulley and line everything up to that. If you can spool it up on a test stand and watch the belt track, you should be good to go. I think you'll have the winning ticket there man.

Ice

Thanks for the information Ice, much appreciated. I will keep all this in mind if I decide to build another belt driven DD Bird. Finally got the parts in to re-build the head on my yellow stretched DD CP450 and while I’m at it, going to add a external BEC. Still don’t know why it shut down in flight, but hopefully adding the BEC might just solve the issue. And this is where I’m at with the tail gear drive DD bird. It’s still a mess, but I’m hoping to get it finish today as I don’t have to go in to work.

[icecycler]

Lucky Guy, off on a Friday, nice to get to play with your stuff. The weather here in the midwest is just awesome, wish I was off today.

Ice

[HELIHANKSTER]

Weather was excellent here to and it was nice to be off on Friday, but unfortunately I wasn’t as lucky as you might think. I had a huge honey do list and my enforcer…I mean my wife was making sure I got a yearly start. I was still able to sneak in to the mancave here and there through out the day and finish up the bird. Was also able to get in two test hops and as I think I’m making progress with this helicopter, there are still issues to over come. I was worried this was going to happen, the tail now doesn’t hold for $h!t. I’m going to mess around with the throttle and pitch curves and see if that helps, but now that the tail rpm are back down near normal operating range, I’m sure it’s just a classic case of the tail not being able to handle the increase torque the larger 360mm main blades are producing. I’ll try all the normal stuff to fix this, but I think the easiest thing to do will be to replace the stock tail hub and blades with the microheli three or four blade setup.







I know my videos suck, but I think you can easily see how easy the tail blows out when I go to give it any kind of real power.
[ame]http://www.youtube.com/watch?v=dDdVM-VgQDk[/ame]

[hochoco]

Originally Posted by HELIHANKSTER

... I was worried this was going to happen, the tail now doesn’t hold for $h!t. I’m going to mess around with the throttle and pitch curves and see if that helps, but now that the tail rpm are back down near normal operating range, I’m sure it’s just a classic case of the tail not being able to handle the increase torque the larger 360mm main blades are producing. I’ll try all the normal stuff to fix this, but I think the easiest thing to do will be to replace the stock tail hub and blades with the microheli three or four blade setup.

Great job, Helihankster! I'm happy that you did not give up on this heli :-)

Regarding the tail authority issue, I wonder how it will perform on a 4S setup.

Also, another thing to try is using the mCPX main blades for the tail as described in this post at the other forum:
http://www.rcgroups.com/forums/showt...9#post21640086
I have used this on mine and so far I'm having a good experience. My setup is different though since I am using a DDVP tail.

HAROLD