alright. lets get to work.

edit: a sort of update for this is here:
https://www.rcgroups.com/forums/show...postcount=1140

edit: UPDATE: a lighter plastic V2 ddvp is described using the HK450 V1 plastic tail box HERE, and in posts #1340 through #1342 below, parts list in post #1350


7 testers and myself are in the air, There are not any more test units available from me, however, i will set up and execute group buys for components at cost.

the second version of the DDVP has been constructed and flown.
altho i am not sending out test units, Version 2 is also trivially constructed, requiring no special tools or skills.

DDVPV1

DDVPV2

DDVPV2 with other motors

the DDVPV2 arrangement is appropriate for several motors, including the C2226, the C20Pro, and the AX-1806C, as seen above.

currently my favorite is the Turnigy C2226 .

edit: use modified blind nuts available from HC that sit inside the motor case. use loctite on the bolt thru the tail plates and spacers

see photo instructions here and here



These are not for sale, i am NOT developing a product, just trying to get people to consider another possibility for the 450 tail, and ultimately to make it better. and it is already very very good.

You do NOT have to structurally modify your heli in any way.you can return your heli to it's original tail system easily at any time.

THE BASIC UNIT: the tail case, motor, motor mount installed in the tail case, and one mounted erod shaft.
this is it: https://www.rcgroups.com/forums/show...8&d=1259794795


WHAT ADDITIONALY YOU WILL NEED:
YOU will need to provide an ESC (10-20A),possibly a servo Y cable depending on how you set up(no Y necessary for 7 ch radio), wire and connectors, the slider, rotor, and servo arm from your current tail( they just bolt right on, no mods).

the only thing you need to do to use the tail, besides bolting it on and wiring it up, is to remove
either the lower main gear(sufficient), and/or the front tail drive gear assembly(harder, but makes more room for wires)

use the Comments or Reply link above to ask a question or talk to us

OR.......

BUILD YOUR OWN!!!! IT'S TRIVIAL!

https://www.rcgroups.com/forums/show...38&postcount=6

Our Team

i haven't formally introduced the people participating in the test so i will.

we are (in approx order of involvement):

frac, rocketscience, sonicj, telemachus, estarter, fpainter3,T3beatz,melnic,DoctorAudio,dze

already one tester is bitching about the quality of the hextronic 2730-1500 motor, which is not really so bad esp considering the price

but,

THE HUNT IS ON FOR BETTER MOTORS

i just ordered these motors to try out. i'm willing to go a little higher on the kv if i can get better motor quality.

http://www.unitedhobbies.com/hobbyci...idProduct=5433

http://www.unitedhobbies.com/hobbyci...idProduct=6633

http://www.unitedhobbies.com/hobbyci...idProduct=6634

http://www.unitedhobbies.com/hobbyci...idProduct=5423


they are all reasonably priced, 3mm shaft motors and at least 2 of them
appear usable with the current mount.

What's wrong with the motor? The first thing I want to to is dissect this thing and figure out exactly what you've done here. Where was that post with the list of parts you used?

Unfortunately, the Trex I'm gunna put it on is in need of a major overhaul, so I probably won't get to this mod till the weekend.

i wasn't b****in', lol! i thought you wanted feedback? ohhh.... just the good kind of feedback, ok.

how about this one?

Gunna post some stuff from the other (long) thread for my own reference:

Originally Posted by frac

you do not have to wait for me to make you one, the DDVP final design has reduced construction to a triviality.


when you receive the HK tail, disassemble it and remove the spacers, the idler and it's supports, the shaft and gear and belt.

push out and remove the flange bearings in the side plates.

this is all you need of the tail, the side plates and the servo arm support(don't even unscrew it), and the boom hub.

the motor has a shaft on it's case that is about 1.5" long. at that end of the motor is a C clip which you remove. there is a brass ring on the shaft ...save it.

pull out the shaft by gripping the rotor but not squeezing it. undo the 2 grub screws on the rotor and remove the shaft. replace with the erod shaft and tighten the grub screws. make sure the rotor bell is perpendicular to the shaft so there is no wobble.

the motor comes with a mount that is extremely strong and very light.
it has 2 grub screws to hold the shaft on the motor case(stator).but it has 4 arms on it that you will need to cut off with a hacksaw(hold it in a vise). use a grinder or file to remove the tab remains
and round the spacer.

then grind or file the height of the mount until it is the same as the spacer's width that came with the tail. this way the side plates don't bend and have no stress.

thus you are left with a cylindrical spacer for the stator between the side plates that locks and stops the stator from moving.

to assemble the tail,put a M2 20mm screw through the tail left plate
most rear screw hole, head facing left, put the wires of the motor though the hole in the left side plate, and then push the plate bearing hole on to the stator shaft. place the motor mount on the stator shaft and tighten the grub screws, and then the right side plate over the stator shaft and the rear most screw. use remaining screws and nuts to secure the motor/sideplate spacer assembly to the tail boom hub and hold the sandwich together.

erod is the ONLY rod stock i have ever bought where 3mm rod actually
fit 3mm parts(eg bearings, sliders etc).

so the only thing left to do is put the brass ring you saved on the shaft push the shaft through the motor and then mount your tail components and boom.

that's it. the most important thing is to balance the tail rotor and not run it too fast if you are unsure of your rotor screws/hub.

i wish it were not raining because the wind is just right to show the DDVP's capabilities.

with the battery mounted(almost any of my batteries) and no additional weighting or adjusting, the DDVP heli balances back to front while holding it by the flybar

Originally Posted by frac

tail unit $8.29 + $0.60 orig shipping cost from HC
motor $8.59 +$0.60
(2) erod shafts $2
bolts,nuts,set screws $2

lets make it $23 + paypal fee.i will send all the unused tail and motor parts that come with them.

the vertical fin is $2.79+.$0.60 but you can usually clamp something else on. i am reluctant to part with these



frac

Originally Posted by frac

these are the components of the DDVP:

http://www.unitedhobbies.com/hobbyci...idProduct=9209
http://www.unitedhobbies.com/hobbyci...idProduct=4859

note that there is a turnigy version of this motor, DO NOT USE IT.
the turnigy version has the cutouts on the rotor expanded for better cooling but in the process they weakened the rotor case and it will bend when you are working with it, unless you take special precautions.it does however come ith bullets and heat shrink, unlike the hextronic.
the price is almost the same for both.

(4) M2x20mm screws
(8)M2 nuts
(2)M3x6 set screws
(1) EROD shaft with flat.

for the vertical fin the HK FG upgrade is perfect because you can trim it so that it screws on without any trouble:

http://www.unitedhobbies.com/hobbyci...Upgrade_(HK450)

any 15+ A ESC will do, i'm using this:

http://www.unitedhobbies.com/hobbyci...d_programmable)

note that a 10A should do, but i blew one when the tail rotor hit the ground. i do not know if the fault was low quality of the esc or a current surge. if the latter a fuse should protect the esc.
eventually we will have some current usage logs of the tail.

you add your current tail control arm, slider and rotor, and an ESC and wiring.

no mods to your heli except removal of the front belt drive gear and shaft (NOT the one on the main shaft) if you run the wires inside the boom.

no more boom strike! and you're done for the day.

just bend the boom back and keep flying.

erod for making tail shafts is available here:

http://www.plastixs.com/ep07.html

Yet another Frac quote:

I used the HC super flexible silicone 20 gauge wire, directly wired to the motor leads and 2mm
bullets at the esc. don't put bullets on the motor end, they come apart. the wires are run inside the boom and then to the esc which is under the base plate directly under the main shaft. there is no electrical weirdness with this arrangement.

as to radio programming,not so hard but depends on your radio, how many chs you have on the rx (7 is nice), and the esc, specifically whether it has a working gov. the problem is how to get throttle hold

1) you have a governor that works on the esc.
parallel with throttle via y connector, set gov for desired speed. TH is automatically available as is normally. this is the ideal solution.

2)put tail on own channel.controlled by a pot.this way you can tune the speed any way you want.getting TH can be a problem, unless you can link it to this channel.

3)straight parallel with throttle without gov. you would have to do this with a 6ch rx unless you sacrificed the gyro gain channel. i was not able to use this because the tail speed at low throttle was not high enough for the tail to function, so i had to use

4)a mix from throttle to ch7 where the tail is with pot bias to get the speed up at low throttle. in order to get TH i had to use the radio modes in this way: normal mode has throttle curve set to zero all across(this is the TH) and ch 7 was biased with a bias mix to be off in this mode.
IDUP1 becomes normal mode (with a pot mixed into ch7 to bring the speed up for low throttle and is adjustable).IDUP2 becomes IDUP.
curves for normal and idup set as desired.

i think that the problem i had with paralleling throttle and the tail may be something with my radio and you or others might not have that problem with yours, we will have to see.

since i do not have futaba/jr/spektrum/hitec/airtronics etc experience i expect that ppl will find stuff on them that can be used to make this work easily and cleanly, and there will probably be discussion about that. i am using the flysky 9X and it works
nicely but i did have to sacrifice idup2.

5) the crazy option. i bought a small pcb servo tester that can be used to drive the esc, it is available from helidirect for $9 and was available at HC for 4 or 5 dollars but is no longer there.
it has a pot on it that you i can use to set the speed. no TH with this one, unless you use something like the turnigy rc controllable switch available at HC to turn the power to the pcb off

instructions for the washers:

when you receive it you will find 2 brass washers on the rotor shaft, a thin and a thick one.

the three tails i made for you guys came out better than my own in that the rotor is square to the shaft. apparently i got better at not bending the rotor case, which you will also have to take care not to do.

thus you will all be able initially to use the thin washer on the shaft between the rotor and the stator bearing.

get a good punch set with a smaller than 3mm punch and use it. don't bang on the end of a shaft with a hammer or you will flatten it and have to file it to remove it, or damage the rotor case.

the thick washer is used if/when you change the shaft and cannot get the rotor case perfectly square to the shaft,it moves the rotor a bit away from the stator .

try to not hit the tail on the ground because at this tail speed you will probably bend the shaft, which can be straightened.

governed constant speed is best, mixed from throttle with bias is fine too.

you can use any rod material you like for replacement shafts but erod is best, available here:

http://www.plastixs.com/ep07.html. they only charged me $4 and change for shipping for 3 250mm rods.it is not expensive.

you are not committed to the shaft length i used.

a diamond file can be used to put a flat on the shaft and is recommended.

the blades (and grips if you can) MUST be balanced or you will have vibration.coloring them brightly will help finding a blade grip if one should get thrown.

replace the screws on your rotor hub if you have any kind of tail strike or you *will* throw a grip
eventually.

you might want to loctite the nuts on the bolts, but i haven't.

you should remove the front tail drive shaft and gears and put the holders back into the frame.

getting the tail servo as close to the boom holder as possible is best, so if you have longer tail servo rods, use them.


vertical fin:
because i used 20mm bolts to clamp the tail together, and the motor also gets in the way, you will have to make another arrangement.

1)http://www.unitedhobbies.com/hobbyci...Upgrade_(HK450)
cutting the circle in a way i will show allows this
to be mounted in the normal way,no other mods
2) use a horizontal fin clamp on boom to hold a tail fin
3) use piece of vertical fin mounted in normal tail holes as a clamp over over some other fin that won't otherwise fit.this allows moving it forward way from the motor and bolts without having to use a horiz fin clamp

The key to the motor Frac is using is that the bearing mount on the motor is going all the way through the tail (cool that its the right length).

http://www.unitedhobbies.com/hobbyci...XM27301300.jpg

What is the ground-down collar holding the motor on?

Originally Posted by sonicj

i wasn't b****in', lol! i thought you wanted feedback? ohhh.... just the good kind of feedback, ok.

how about this one?

yes it was bitchin!! i bitch too or haven't you noticed

but i've already said that i'm not thrilled with the hextronic 2730 because the rotor case can bend, and i had problems with mine getting the shaft square to the rotor, which btw didn't happen with all of yours,
and this results in a serious vibration problem.in fact, one 1700kv motor i was using had the whole flat part of the rotor pop off.

but in your case i must have dinged it. if you look at the hobbycity
and other sellers pix of this type of "pancake" motor, the windings are typical in all brands

but you're a hotshot/fusspot who winds his own! see, i knew we needed you

i like this first motor in the list above....looks nice and solid.

i was also looking at the DF300 at hobbypartz but it's $28, and that is getting un-economical.

going to have to start thinking about a simple mount for the motors without that extended case piece.

i assume you guys will try some other motors if you can, i don't have infinite financial resources

looking at your link i see it's the same as this one:
http://www.unitedhobbies.com/hobbyci..._19g_Outrunner

which i have already tried on my cp2....and i really wrecked it trying to get a shaft in and mounting it. which is not to say you won't do better especially since the 3mm erod fits the bearings unlike freaking 3mm drill rod. it is 19g and that's why i bought it.

i've been at this thing for a while now......the cp2 inspires crazed fanaticism about the tail, ask gino

Originally Posted by Telemachus

The key to the motor Frac is using is that the bearing mount on the motor is going all the way through the tail (cool that its the right length).

JUST the right length. great serendipity.

this was originally the motor used by EQMOD on his cp2 tail, and he used a cp2 blade grip to clampi it and mount on the tail "stick" ( it doesn't deserve being called a boom )

http://www.unitedhobbies.com/hobbyci...XM27301300.jpg

What is the ground-down collar holding the motor on?

this is the 1500kv btw not the 1300 but they have the same dimensions, as does the 1700 also.
i have one or 2 of the 1700kv i might send out to you guys

the setscrews hold the extended round piece on the stator, and the collar is held compressed between the tail plates. you can put another screw or 2 in the tail plates if you want but i haven't seen the need.

without the collar/spacer, the motor will rotate. if it rotates, the wires are wrecked.

it's more important not to stress(bend) the tail plates or they will fracture, as i showed in a pix in the BR thread.

i must admit that i am a bit unhappy about the way yours came out
the grinding wheel needed dressing and it is not as flat as i would like.
i can send you another one and you can try your hand.

this mount i converted is very interesting metal, nice and light, easily filed and ground, but i found it impossible to cut with a hacksaw without a lot of effort

What is your source for the metal for the mount? Did you have to cut the 8mm hole in the middle and tap the hex screw holes?

I also don't understand why you would be any more likely to throw a blade grip with this as a regular belted tail. Are you running this thing at 100% throttle? If so, then at 12 volts, you are hitting about 16000 RPM!! Most people run their 450's with a main head speed of 2600 to 2700 RPM, and with a 4.3 to 1 tail to main ratio, the tail should be in the 11000 RPM range. That would mean governing your 1500kv motor to run at about 70% throttle.

Lest any un-initiated are following this thread, below are the pics of the Frac DDVP tail components

https://www.rcgroups.com/forums/show....php?t=1035211

towards the end i have a post with 2 links in it, the first is to PhilR's
very clean and elegant motor mount design, which i think will work well for scale.

the second is beer-man's home-made frankenheli, which he loves.

Originally Posted by Telemachus

What is your source for the metal for the mount? Did you have to cut the 8mm hole in the middle and tap the hex screw holes?

this is the mount that comes with the motor. originally it has four "arms" on it that i hacksawed off and then rounded on a grinder. I also had to drill through the mount with a 5/16 drill to get rid of a lip on one side that prevents the motor from going all the way thru the mount.

it comes with the tapped holes for the setscrews on it. i replaced the small grubs that came with it with the larger so they could be kept track of more easily.

this is the best thing about this design, it is very easy to make, no machining, no special tools, no weird mods on the heli.

I also don't understand why you would be any more likely to throw a blade grip with this as a regular belted tail. Are you running this thing at 100% throttle? If so, then at 12 volts, you are hitting about 16000 RPM!! Most people run their 450's with a main head speed of 2600 to 2700 RPM, and with a 4.3 to 1 tail to main ratio, the tail should be in the 11000 RPM range. That would mean governing your 1500kv motor to run at about 70% throttle.

yeah if speed were the issue a heli in idup would be throwing grips too,
which i think mrmitch did a few times.

when i switched to erod from drill rod the problem stopped.

also hitting the tail on the ground at hi tail speed will weaken the rotor hub screws.....all the thrown grips' bolts broke in the tail hub, and once the threads were ripped out.

so i'm thinking crappy bolts and/or shaft flex, alto the latter above suggests hi rpm

as i said in my pm, my esc, altho it doesn't govern, does seem to limit and i don't think i get much beyond 13-14K....i think that's what i logged with the eagletree.

and altho the theoretical calc shows a high speed, under load i think it is much less

btw watch that rear bolt it looks too close to the stator coil. i usually set it so that the motor bearing on the other side is flush with the plate and then there is adequate clearance, you have it pushed thru a bit more. i also rotate the motor slightly so that the bolt head sits over the "valley" in the winding giving additional clearance.

the cap on that bolt is too tall and the next time i place a screw order i will be getting some with the lo profile rounded head which will give us much more room . if you have any, replace that bolt.

edit: actually it occurs to me that you could just grind/file the head down a bit.i'm going to do that on mine

however, once tightened up, i have not had the motor or tail components move after many flights.
except for the nuts. the outer of the pair loosened.

looking through some of the older threads,i see that they recommend using CF tail blades prolly for the rigidity, if you have them, use em.

rocket was concerned about the shaft moving since only the magnets are holding it in place. i have not had any problems with this except when i was bending drill rod shafts which would push it a bit when pitch was changed, but if you are concerned, use a diamond file to make a notch in the erod on the rotor side and put a C clip on to hold it. i haven't found this necessary at all

these tiny little magnets are unbelievably strong. there are 16 in the rotor (16 poles for eagletree users)

older DDVP discussion threads. dieselracer of the edzinator video is in this one and defends the concept along with Reflex1, another strong supporter
https://www.rcgroups.com/forums/show...drive+450+tail

and 2 more:

https://www.rcgroups.com/forums/showthread.php?t=492675

https://www.rcgroups.com/forums/showthread.php?t=288487



as i find more of the old threads i will post links, each of the threads above have additional links within them