direct drive motor 450 pro cp / fp

[AtTheCross]

i think it will be a kewl exercise, but it's going to be noisey

[johnnycat500]

If I remember right HH, the problem with the fp frame and shaft was because we were using the beam drive gear and the shaft needed a hole thru it for that gear. You should be able to use a longer 450 shaft and just use a collar on top since it now has a set screw drive gear.We can mod the frame if you want to give TT a go. All the work is done with making the original cnc file. I copy the file,make the changes and save as DD 450 pro cp/fp/tt ..LOL My DD 450 fp is apart so I will drill out the motor so it will take the 5mm shaft. Also a good time to stretch the boom as a counter balance to run 4s on it.

[HELIHANKSTER]

Originally Posted by AtTheCross

i think it will be a kewl exercise, but it's going to be noisey

Yeah, noise would be the downside and trust me, I’m really digging how quiet the DD is. Yelper, how quiet the DD is definitely part of its cool factor. My main reason for thinking about trying the TT mod is the darn super long 505T belt I got from SDP to stretch this puppy just wont stop stretching. lol! I even mark the boom to make sure it wasn’t moving. I know it will get to the point where it doesn’t stretch much and all should be good…well I hope so. But right now it annoying…before a flight, good belt tension, after the flight, loose as a goose. I’m telling ya, 4s really puts a hurting on the DD drive train. This is why I was thinking of trying TT on the next build and figured only having a small belt between the two pulleys would be less maintenance. I don’t have many if any tail strikes, so not worry about stripping the TT gears…You know me, when I crash, I go big and there’s usually nothing left. lol!

[HELIHANKSTER]

Originally Posted by johnnycat500

If I remember right HH, the problem with the fp frame and shaft was because we were using the beam drive gear and the shaft needed a hole thru it for that gear. You should be able to use a longer 450 shaft and just use a collar on top since it now has a set screw drive gear.

Okay, now I remember JC.
I’ve checked on cnchelicopter website a couple times and I think they are not going to re-stock the 50T set screw pulley. I want to leave the current DD stretch alone, so I think I will try to make the beam shaft and 46T pulley work on the next build. I’m thinking the 46T pulley would be better suited for a 4s setup anyway and this DFC head should solve the problem with the beam shaft being shorter.
http://www.infinity-hobby.com/main/p...oducts_id=8115

Originally Posted by johnnycat500

We can mod the frame if you want to give TT a go. All the work is done with making the original cnc file. I copy the file,make the changes and save as DD 450 pro cp/fp/tt ..LOL

Awesome brother!
Too cool, but before I get up with you on the TT frame design, let me order some torque tube front drive gears and make sure I can actually mod the front TT gears with the 11T pulley. Wouldn’t want to go through all the trouble and find out it’s not going to work.

Originally Posted by johnnycat500

My DD 450 fp is apart so I will drill out the motor so it will take the 5mm shaft. Also a good time to stretch the boom as a counter balance to run 4s on it.

Sweet, let us know how it goes. If I get a chance this weekend, will go ahead and drill out my spare motor. Bro you should love the stretch version, I know I do. I’m so glad I stretched my DD bird, not just because it needed it for performance, but because it’s amazing how a little extra blade and tail makes it feel so much more stable and smooth…well compared to my stock HK Pro it feels more stable. lol!

[ScotY]

I have an idea...no idea if it's workable though. How about a second motor for the tail? It could sit just in front of the tail boom mount so you could use stock length boom and belt yet still have enough clearance for long blades, frame would have to be extended but you could do away with all the pulleys and stuff. Of course, you'd have to source an appropriate motor but it would remain a quiet helicopter.

[icecycler]

HH, What I did on my latest 450FP (see your Flybarless thread for pictures) was take a 12 toothe MXL sheave and replaced the stock tail drive sheave. With the 68mm tail rotors it really made a difference on stability for this bird. Bringing up the tail rotor speed makes a huge difference.


ice

[HELIHANKSTER]

Originally Posted by ScotY

I have an idea...no idea if it's workable though. How about a second motor for the tail? It could sit just in front of the tail boom mount so you could use stock length boom and belt yet still have enough clearance for long blades, frame would have to be extended but you could do away with all the pulleys and stuff. Of course, you'd have to source an appropriate motor but it would remain a quiet helicopter.

Hi ScotY, how’s it going

Is this what you had in mind, if so I think it’s totally doable? I’ve built a few DDVP setups on my small fixed pitch bird and have had good success with them. My only issue with my DDVP tails was, in a crash the modified tail shaft would bend like butter and it became a big pain in the butt to keep having to make custom shafts. I do like your mod idea for a couple reasons. Being able to keep the stock tail configuration, so changing bent shafts would be a breeze and having the bl motor driving the tail in the frame, not on the tail box would really help with CofG issue the standard DDVP is famous for. My only concern is, on a standard DDVP setup the tail rotor is directly attached to the motor shaft, on this mod the motor will have to handle the increased drag of the belt and I do wonder how big the bl motor would have to be to get the job done.



I hope though I haven’t given anyone the impression that the belt drive setup on the DD CP450 or in this case the stretched CP version is bad. Because it’s not, the issue is the belt itself and really it’s not an issue. I thinking the material use to make the belt I ordered for the stretch just has a tenancy to stretch more in the beginning than a standard tail belt. It’s already getting better.

[HELIHANKSTER]

Originally Posted by icecycler

HH, What I did on my latest 450FP (see your Flybarless thread for pictures) was take a 12 toothe MXL sheave and replaced the stock tail drive sheave. With the 68mm tail rotors it really made a difference on stability for this bird. Bringing up the tail rotor speed makes a huge difference.


ice

Okay Ice you got me with the word “sheave”. I’m thinking it an old school word for “pulley”. lol!

Definitely Bro, increasing tail rpm on the FP450 is a must. I found the easiest way to do that on the FP450 was to trim down the FC main blades. That way there’s no real need to mess with the tail gear ratio.

On the DD CP450 there’s no issue with having enough tail rotor rpm…well actually I think the DD CP450 on 4s has a little too much tail rotor rpm.

On the standard 450 the avg. tail is around 11500 rpm.
On the DD CP450 running 4s I come up with an avg. tail rotor rpm of 13000 +.

This high rpm is why I want to use the beam 46T drive pulley on my next build.

[johnnycat500]

HH. The last HF member I sold a frame to sent me a pic with the motor parallel to the tt shaft. Use a stock tt tail case gears and shaft and a coupler to connect motor to shaft. It would be direct drive You could use the stock pro motor mount and drill 4 holes in the frame. You would have to use the alum boom blocks as the stock one will be to big. I will find HF member's name to give him credit.

[HELIHANKSTER]

That setup sounds pretty darn sweet Johnny. Do you still have the picture he sent you? Would love to see how he made the coupler.

[johnnycat500]

I will try and find it when I get home. He did not do it he just sent the pic. He wanted to know if I could cut a frame to do it.

[HELIHANKSTER]

Ah, okay it was just a mock up picture. Definitely sound like a cool idea, pretty much the same inline DD setup that in our robocopter right?

Hey bud could you check and tell me if this is right.
Distance between center of pulley to center of pulley is 39mm
11T =7mm diameter
46T =33mm diameter
I’m thinking a 81 to 83T belt should do it.

[johnnycat500]

The pic was of a 500 or 600 with it installed

[HELIHANKSTER]

Wow, a 500 or 600...that would be a serious motor.

[johnnycat500]

I found them. It was hochoco that sent me these. His build is page 17 # 164 in this thread.

[HELIHANKSTER]

That is seriously bad a$$!
Sucks, you can’t see the coupler in the pictures.

JCAT, think you can make a coupler that would work on the front Pro TT setup? That inline tail is totally sick…We got to try it one day.

[johnnycat500]

Of course LOL .The coupler will be easy. Diameter of tt shaft, diameter of motor shaft and 2 set screws. If the motor you pick will go on stock pro motor mount will just have to cut rectangles in frame for motor.

[ScotY]

Hey HH,

Yeah, that's pretty much what I had in mind...looks like it would work. I'd assume if you found a motor that would swing a prop about the same size as the tail rotor at the rpm you want, that ought to be a good starting point.

The problem with extended booms is finding a good belt. Not sure what makes them better, but Japanese made belts don't stretch as much yet are still supple. The other thing is the boom ID is a little small...the longer the belt, the more it sags in the middle which, I would assume equals more friction from drag/rubbing. The 450 has been using the same ID boom from back when blades were quite short.

The torque tube drive is neat, but you can't beat the simplicity, durability, and quietness of a belt. Life is always a compromise! :-)

[HELIHANKSTER]

Originally Posted by johnnycat500

Of course LOL .The coupler will be easy. Diameter of tt shaft, diameter of motor shaft and 2 set screws. If the motor you pick will go on stock pro motor mount will just have to cut rectangles in frame for motor.

Sweet!!!
Ummm…so picking the right motor would be the only hard part.



I thinking a 1000kv motor with a diameter of no more than 28mm might do it.
14.8 x 1000 = 14800rpm 80% rule = 11840rpm…should be about right I guess.

[HELIHANKSTER]

Originally Posted by ScotY

Hey HH,Yeah, that's pretty much what I had in mind...looks like it would work. I'd assume if you found a motor that would swing a prop about the same size as the tail rotor at the rpm you want, that ought to be a good starting point.

Again finding the right motor…not my strong suit. lol

As for the tail motor mod itself, I think it would be fairly easy to do. Use the stock Pro motor mount, find a motor with a 3mm shaft. Change out the upper and lower bearings in the tail boom mount to ones with 3mm ID. Cut down a 3mm main shaft (like a fp honey bee main shaft) to fit the motor and boom mount. Put a Trex 11T Tail pulley on the 3mm shaft and lock it to the shaft with green loctite. Done…sweet!

Originally Posted by ScotY

The problem with extended booms is finding a good belt. Not sure what makes them better, but Japanese made belts don't stretch as much yet are still supple. The other thing is the boom ID is a little small...the longer the belt, the more it sags in the middle which, I would assume equals more friction from drag/rubbing. The 450 has been using the same ID boom from back when blades were quite short.

These are definitely the issues I’m seeing with the custom belt and stretched boom. That’s why I want to try and do the belt to TT Mod. Heck, if this belt to pulley to TT gear design works good on the Mikado Logo Xxtreme, it should be fine on the DD CP450...well I hope it will.

Originally Posted by ScotY

The torque tube drive is neat, but you can't beat the simplicity, durability, and quietness of a belt. Life is always a compromise! :-)

True that Brother, belt is the way to go as long as there no issues with said belt. Wish I could get a kevlar belt like the one on my 250 custom made for the stretch DD. Thinking that would fix me right up.