The 'Speed WARP' build thread!

[jp0160]

I'm a bit out of the loop here... Can someone explain "dual stage" to me? Is it kinda like a 2-speed transmission?

[BaconRaygun]

Originally Posted by jp0160

I'm a bit out of the loop here... Can someone explain "dual stage" to me? Is it kinda like a 2-speed transmission?

No, not at all. Duel stage means using two sets of gears (or in this case pulleys) to transmit power to the main shaft. Stock only uses one set of pulleys, the 'pinion' and the main pulley.

I already wrote the point of going two stage in my main post, but to reiterate, the point is to make the heli narrower and to allow a greater range of gear ratios.

If you are just after 3D or not looking to stretch the heli, then there is no point in doing it as it just adds complexity, however, if you are looking to stretch the heli, or if you are looking to build a narrow speed fuselage, then it is almost a necessity.

Notable helis with a two stage drive train are the Goblin, TDR, Diabolo, Banshee and I think some older ThunderTiger helis. I'm sure there are others too...

[velocity90]

Voodoo :p

[Luvmyhelis]

I like it! Well done! As a side note, My two sets of Edge 473s just showed up this afternoon. That with this dual stage may be my ticket here. This is gonna be a great winter project again.

[BaconRaygun]

Just got my shipping confirmation, so next week it will be time to drill the frames! I think I figured out my tentioner solution too, but not going to order anything till I have the belts.

[BaconRaygun]

UPS man came today, delivered me my belts so that I can continue the design and build.

The S1 belt ended up a little on the large side, so I went ahead and ordered a smaller 90mm belt. I realize now that I made a small mistake when measuring, but no big deal, that belt cost me $4.

I figured out the tension mechanisms and ordered the parts needed.

S1 tension will be provided in a similar fashion to stock, except a little differently. I sized out the bearings and nothing worked with the 3M bolt, so I went snooping around on Misumi and realized that I can have them grind me a shaft to my liking. The idea here is to use a 6mm shaft, threaded on one side, and drilled/tapped on the top. The threaded end will go through the tension block so that I can mount the belt-guide just like stock, however, the shank will be 6mm, so that I can choose the correct diameter bearings to provide proper tension.

Since the belt angle in relation to the pinion pulley has become much more acute due to the dual stage, the stock tensioner will not work. I figured this is the lightest and simplest solution. I will use two stacked 6 x 13 x 4.5mm bearings as the tension roller.

S2 tension will be provided by a loaded radius arm. Originally I tried to size a part already made by other manufacturers, but this proved to be a futile effort. Solution? I ordered a delrin block and I will mill it by hand, its just an arm with a hole for two bearings and two holes for 3M bolts. One bolt will get a spacer and bearings for tension, the other a spring or rubber band which will be mounter to a point on the frame.

Now I wait another week and a half to receive my parts!

[NevErSn0w]

Ahh, I'm keen to see the turnout

Trex 500 esp, Compass Warp 360, Spektrum dx7s

[Luvmyhelis]

Hey, any further progress?

[BaconRaygun]

Yes, I am at the stage where I drill the holes in the chassis. Lots of hand filing, I am going to post images as soon as I'm finished with this step... And once its done, I will have a better idea of which bearings I need to order for the tensioners.

I only got one hour of work in since I received my last parts order which contained the 90mm belt, shafts and a delrin block. Need a few more hours.

[BaconRaygun]

Ok, here is where I am. I just finished the top mount for the two-stage, this basically required drilling two holes in the stock motor mount and elongating them with hand files to allow the tension to be set as well as provide a solid mount for the upper block without drilling into the narrow strip of CF available on the frame.

The cool part about this is that once you set the tension for S1, the whole mount (motor and the S1/S2 pulley-shaft) move in unison.

I'm in a hurry because I have a Halloween party to go to, so I only snapped a few pictures. All those wondering, when I do the final build, I will take pictures of each step and explain what has been done and how to do it yourself.

...and obviously, this is not going to be an easy part to assemble. You thought getting the washer between the main pulley and lower block was a PITA? Well, getting all of this into a tight space is even more tricky.

[Luvmyhelis]

That, is some very cool work bro!

[Bob O]

Wow Igor..........I'm impressed with your implementation of the existing parts.

[BaconRaygun]

Thanks guys!

Today I've got all day to work on it, so I'm gonna get the frames drilled and start on the belt tensioners.

Stay tuned!

[Luigi_tuga]

Originally Posted by Bob O

Wow Igor..........I'm impressed with your implementation of the existing parts.

+1

Very efficient approach

[BaconRaygun]

I encountered a little dilemma today regarding the S2 tensioner.

The problem is, regardless of how I do it, the bolt holding the tension bearing will interfere with the tail belt... the solution? Easy, extend the tension bearings so that the smooth side of the tail belt also rolls on the tensioner. Since both S2 and the tail belt will be moving at the same speed, there is no issue with the roller needing to be split.

Here is the dilemma, with this configuration the stock belt may be too short without further mods.

I ordered a slightly longer belt @ 1196mm, stock is 1064mm.

With the larger tail pulley, and two sets of tensioners, the 1196mm belt should be perfect, but if it is too long I will have to slightly shorten the boom.

As for the tensioners, I am taking a different (simpler) approach from my original idea of using a radius arm. Its brutally simple, I'm going to stack a few 3 x 8 x ?mm(tbd) bearings on dual shanked 3M bolts and bolt them into the lower block... it already has two tapped 3M holes.

This portion of the project should be complete and ready for a test flight in about a week.

[BaconRaygun]

Another update, here are the bearing-dimensions I will be using.

S1 (motor belt) tensioner: 3 x 10 x 4mm Flanged, X2. I've seen people machine special guide rollers, just like Compass does stock... but that's just not necessary when you can just take two flanged bearings and stick them on a bolt with the flanges opposite of each other. Bigger bearings which will last longer AND no special tools needed.

S2 tensioner: 3 x 9 x 4mm x3 and one 3 x 9 x 5mm Flanged. The flanged bearing may or may not be used as a partial guide.

Bearing Blocks: 4 x 8 x 2mm Flanged, x4. I chose NOT to use bearings of the same dimensions as stock (4 x 8 x 3mm Flanged) but you can if you want. My reasoning is that four races supporting a shaft which is handling opposing forces is better than two, so I'm gonna use two bearings per block. The flanges are .5mm thick, leaving me a combined 3mm of un-flanged bearing, perfectly filling each block.

...and that's it. The test flight is pending the delivery of the above bearings as well as another 18T pinion, 4mm id washers, 2.5M washers and a main gear to hack up as a shim.

[Luigi_tuga]

Cool!
Will you be using your Scorpion, or have you geared with the 1880 kv in mind?

[BaconRaygun]

Both! Simply swapping the S2 pinion to the 18T gears the heli very close to what you get with a 17T pinion stock. Swapping the S2 pulley to a 16T gears you at 9.609:1, perfect for the 1880kv motor.

With this mod, you have the option of swapping both pinion and S2 pulleys to fine tune your final ratio.

I'll post a list of ratios at another time.

[BaconRaygun]

Available ratios with a 30T pulley.

[BaconRaygun]

Yesterday I got the main gear in the mail from 203killer1 and today I got to work on the spacer. Here is what I did.


It's pretty straight forward, all you need is the stock main gear, some dyke cutters, a main shaft, your one-way assembly, some sand paper (I used 100 and 220 grit), tape and a drill.


I took the pulley, mounted it to the OWB assembly and cut off the outside portion as follows.


I then trimmed it down as much as I could.


I then inserted the main shaft and added some tape behind the assembly so that it would not slide off while 'milling'. I then attached it to my drill.


At this point I very carefully milled it down using the 100 grit sand paper. It was a bit tricky because it did not grind down evenly so I had to stop and do some sanding by hand. Once I did that, I lightly touched the hacked pulley to the 100 grit as I spun the drill so that only the high spot would touch... eventually it was satisfactory and I finished with 220 grit.

It's not perfect like a CNC job, but its no worse than any molded gear! Spinning it by hand, it spins truer than the pulley which is mounted below it.

Here is the final product.









My bearings should be in tomorrow or Tuesday, then its final assembly and testing time!