RunRyder - TSK My Star 30 conversion

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e-Electric Conversions > TSK My Star 30 conversion

watersteps
Senior Heliman
Location: Manchester Pa. USA

Hi Shadowfox,

Well I want to stay with the main gear and it is a 77 tooth mod 1, because it drives the cog that drives the rear rotor belt. With all the help you guys have offered I now know that I want a 300 to 500 KV motor with a 9 to 12 tooth pinion. I want to keep the top bearing block from the old clutch bell pinion so the pinion will rest in the bearing in the bearing block so it will not be totally dependent on the motor bearing. For this reason the pinion must be long. Even if I don't use the bearing block I will still need a long pinion. That would be between .750 to 1.00 inch long and that would be the length of the splines, and I can't find one as of yet. The motor will have a 5 or 6 mm shaft so the pinion will have to match that size. I have spent hours and hours on line trying to get drawings of pinion gears like JR, no luck, Losi, no luck, Hobby Products, no luck, Kimbrough Products, no luck, and others. The problem is the motor must be mounted just below the frame and that means it must be long. If I could find the long pinions I would purchase several, 9,10,11,12,13,14 tooth. Then I can purchase the motor and mount it.
Then I will move on to what Gyro I need.

watersteps

06-19-2007 Over year old.

Shadowfox
Senior Heliman
Location: ABQ,NM

tppacks.com makes rappy pinions similar to what ya asking. Call Gary he will set ya up.

06-19-2007 Over year old.

Ben-T-Spindle
Elite Veteran
Location: Central Illinois

I have noticed that the Raptor E-series pinions are wider than most. You should check to see if they would fit.

... BTS

06-19-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

Thanks Shadowfox and BenT,

I will check them out today. After laying out the frame and main gear on paper I believe I can use a pinion with a minimum spline length of .500 inch if the motor I choose to use has a .750 to .875 shaft length. OK, now I have to sort through my notes and find the motor.

Finally some progress, I love it, I could build these helis 24-7 if I won the lottery. Guess ya gotta play first!

By the way guys, do you know of any RC company that prints a large catalog? I think TowerHobbies does, anyone else??

watersteps

06-20-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

Well guys I found an Hyperion Z4025-16 with a 6 mm by 30 mm long shaft and 368 KV. Now I need the 6 mm pinions, got any ideas? I could not find any Raptor pinions.

watersteps

06-21-2007 Over year old.

Ben-T-Spindle
Elite Veteran
Location: Central Illinois

I have seen others try to use Hyperion motors on helicopters and they usually run very hot and burn out in a few flights. You really need to get one of the proven brands that work in helicopters like Z-Power, Neu Motors, or Hacker outrunners.

... BTS

06-21-2007 Over year old.

Shadowfox
Senior Heliman
Location: ABQ,NM

dont pull the trigger on that hyperion just yet. What we are sying is that ya need a spacer on the motor shaft to get it up to the main gear. I know MA might have what ya need also. Search Stratus conversion on here and see what I mean.

Id go with the Z30A previously mentioned or the Z50A-600 motor and 8T pinion. Not sure what the #'s look like on that but the Z50A is generally a 600mm blade motor!

06-21-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

Thanks guys, I'm working on sizing up a Z50 right now.

watersteps

06-22-2007 Over year old.

Ben-T-Spindle
Elite Veteran
Location: Central Illinois

The Z50 is a very powerful motor – you won’t be disappointed. A Z50 has more power than an OS 50 Hyper so it should really make that helicopter jump.

... BTS

06-22-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

I have a concern about using the Z50! When I do the math, 77 teeth main gear, 8 tooth pinion, 8s lipo, 565kv on the Z50 = 1685 at 29.6 and 1572 at 26.22 and 1458 at 25.6. That all sounds good but will the 8s with the 8 tooth pinion run OK or will it heat up? Also if the 8s has 2000ma should I double up on the 8s's to make it 4000ma??

watersteps

06-23-2007 Over year old.

Ben-T-Spindle
Elite Veteran
Location: Central Illinois

Your math is NO good.

Motor RPM = Kv * (V – (Rm * I))
Where Kv and Rm are the motor constants.
I is the current at full collective load.
V is the voltage at the motor (you have to subtract internal resistance losses of the battery, ESC, and wiring.

You can estimate RPM by taking 80% of Kv * battery voltage.

So for an 8s LiPo and 565 Kv motor you get.
29.6v * 565 = 16724
take 80% of that and you get 13379.
With an 8t pinion your gear ratio is 77/8 = 9.625
You will get a headspeed of 13379 / 9.625 = 1390 (a bit on the low side)

You will probably need a 9 to 10t pinion to get a reasonable in-flight headspeed.

A 2000 MAH battery would be good for few minutes of hovering. A 4000 would give you a more reasonable flight time and power enough for aerobatics.

Another good solution would be a 800 Kv motor and a 5000 MAH 6s battery – that combination has mad the Trex600 a 3D winner.

.

... BTS

06-23-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

Well OK my math is no good huh? Well thank you for telling me the correct method of siffering these here numbers! Now I feel better about the Z-Power motors. I checked the sizes and they are great, I will now lay it out on paper and if looks good I'll order one tonight or tomorrow. Well I guess I better go study my math so you don't yell at me anymore!

Thanks a bunch BenT I understand, now.

watersteps

06-23-2007 Over year old.

helinutz
Senior Heliman
Location: Bournemouth, Dorset, UK

Ben-T
Nice calculations, but you are using 3.7V per cell to work them out.
surely this should be at least 4 volts per cell as this is the fully charged figure (well, 4.15 to 4.2 realistically).
At 3.7 volts, most are finishing their flight.
Based on 4 volts per cell, that would increase the headspeed to 1500, which is a bit more realistic (although still too low in my opinion)
Using a 10 tooth pinion and 4 volts, my calculations are -
8 X 4 (V) = 32 X 585(kv) X 10 (Pinion) / 77 (maingear) = 2431
2431 X 80% (efficiency) = 1944 rpm
Should suit the mystar down to the ground on a 10 tooth in my opinion

P.S. It doesnt matter if you work out the 80% at the end, as the calculation comes out the same

Think of how stupid the average person is, and realize half of them are stupider than that

06-23-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

Thank you helinutz,
I will lay out the different motor sizes and see which ones will fit in the heli.

watersteps

06-24-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

As I stated before I wanted to check the physical size of Z50 motor to see if it would fit in the heli. To accomplish this I had to disassemble the heli.

While I was doing this I found out that my first motor mount was not wide enough to permit me to utilize all 4 motor mounting holes.
Given the size of this Z 50 motor I wanted to make sure it was bolted securely in place.

So now I need to make another motor mount. The new wider mount will fit up inside the frame. This will require some cutting of the side frames. In order to lay this out and make sure both sides are cut the same I seperated the left and right frame.

I made a drawing of the mount and now I will start laying it out on some .250 by 2 inch by 2.500 inch aluminum bar stock.

watersteps

06-24-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

As I mentioned in my last post, I wanted to make another mount that would allow me to use all 4 mounting holes on the motor. So here is the new blank before I start drilling and tapping holes.

Here the frame has been cut out to allow the wide motor mount to fit up in the frame so the motor shaft with pinion will match up to the main gear. I marked the area where the frame was cut out with a black marker on tape.

Here the tape has been removed to show just the cut out.

These pictures show the new mount in the frame, I now have to drill and tap the mount so I can pre-fit it in the frame. More pic's as I get time to work on this conversion.

07-01-2007 Over year old.

Shadowfox
Senior Heliman
Location: ABQ,NM

nice work Water!!

I know my work wouldnt be near as nice! Never in my life have I got holes to line up or pieces to fit the times I have got it in my head to do mods like this.

I cant wait to see ya fly this beast!

07-01-2007 Over year old.

helinutz
Senior Heliman
Location: Bournemouth, Dorset, UK

I have a Z50-800 mounted in a sweet 16 and a Tango 45-7 in a 3DMP.
Both are only held in with 2 bolts.
Also the T-rex 600 only uses 2 bolts to secure the motor, so I am wondering if you really need to go to a 4 bolt system for this size heli.
Whats your thinking?

Think of how stupid the average person is, and realize half of them are stupider than that

07-01-2007 Over year old.

watersteps
Senior Heliman
Location: Manchester Pa. USA

Thanks shadowfox, I would not be able to build this baby without help from guys like you.

Hi helinutz, I think you are correct, after I cut the new blank I saw several heli's with just 2 mounting screws. Since the frame is cut out I must continue with the wide mount. My problem Is I try to build everything "bullet proof". Thanks for the info. How does that Z50 run? Any heat problems, what pinion are you using?

watersteps,

If you're gona be dumb, ya gotta be tough!

07-01-2007 Over year old.

helinutz
Senior Heliman
Location: Bournemouth, Dorset, UK

Will update about the motor on the Henseleit section soon. 10 tooth pinion has just arrived for the 3DMP, and going to fit it to that to test.
Ran it briefly in the sweet 16 , but the Kv is a gbit too high, so swapping it out for a Tango 45-07.
First impressions are it certainly feels a wwell built motor, so fingers crossed.

Think of how stupid the average person is, and realize half of them are stupider than that

07-01-2007 Over year old.

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e-Electric Conversions > TSK My Star 30 conversion

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