Design - Leviathan Gas Goblin - Generator Mounting

[carey shurley]

watch this space and provide your feedback for adding a generator system to the Leviathan Gas Goblin!

[jc23cl]

Ok, like Carey said

And as a humble request from Raja, I'll try and talk you through it.

For those that may want the Gen option, I have roughed out a light weight setup.

It is essentially a torque arm motor mount configuration (standard Industrial style).

The motor is mounted to a G10 or Carbon plate, the shaft has a rigid mount/sleeve, this allow the motor to spin concentric. The torque is countered by the standoff, and cusioned with a standard grommet. There is a little clearance b/w grommet and standoff post, maybe 0.5mm, to allow a bit of compliance or float.

The assembly is topped off with a standard SAB tail washer. The post can be aluminium, the coupling steel ( note: it is only slightly larger than a starter coupling, and just replaces the starter coupling) and as mentioned the torque arm can be 2-3mm G10 or Carbon. The screw is a 50mm M3 to hold the post stack down.

Parts for this are easily made and therefore should be cheap as well.

Anyways, happy to do a rigid platform with a compliant coupling, but I thought I'd run this past the Gurus first













Note that this will obviously eliminate top start, and the one-way bearing in the starter yolk, will need to be flipped over.

Note also for scale, from the top plate to the bottom of the motor is 30mm, fairly compact.

Also, if there is a call for it, to maintain the top start, I can easily design a small 6mm belt and pulley arrangement, more parts therefore more $$. Let me know.

Regards Joey.

[carey shurley]

as you know, my major complaint with this setup is the loss of the top start option. So I'd certainly favor an offset belt drive. A little more complicated but hey this whole thing adds complexity anyway.

[brw0513]

That torque reaction arm would work well and, in my mind, is a much better arrangement than a rigid mount and flexible coupling. But there should be an elegant solution to provide for a generator and keep the top start ability.

Can the drive belt be double sided and have the generator's pulley driven from the "off" side?

Can the generator be driven directly off the main gear somehow?

[Sowa]

I would only consider a generator for my goblin if it was lightweight and still allowed for top start.

[Azalin]

Originally Posted by brw0513

Can the generator be driven directly off the main gear somehow?

Like this one? I made it for my HelixHeli 600. Works perfect.

[R_Lefebvre]

Too bad you can't get a suitable motor with a hollow shaft. They have them for brushless gimbals. The starter shaft could pass through.

Alternatively, if the motor shaft were large enough, you could put a starter hex on the other end (top of motor), and pass the torque through the generator shaft.

[LoveToFly1]

Originally Posted by R_Lefebvre

Too bad you can't get a suitable motor with a hollow shaft. They have them for brushless gimbals. The starter shaft could pass through.

Alternatively, if the motor shaft were large enough, you could put a starter hex on the other end (top of motor), and pass the torque through the generator shaft.

it would spin the wrong direction then....unless you totally eliminated the OWB on the start shaft, and relied only on a OWB in the starter, which I am not sure I would be comfortable with.

[Rudy]

I have never used that top start on either of the gassers I own, and dont feel I ever will.

That said I would be willing to try the top option due to the lower parts/cost. Also it would keep it simple.

Raja and I looked at this a couple of weeks back and one area that we were worried about was the height of the generator. I have not desire to cut a hold in the top of the canopy to make room for the generator.

[rbort]

I'm afraid that the single bolt on the stud is going to shear over time due to vibrations and cause the generator to get damaged. Also looks to be "weak", any mishap from a crash will cause more damage to the generator system.

The mount I have for my designs comes up from the side frames to a top mount plate and should work perfect just the same on the goblin. I believe there is enough room in there to fit it, and use the existing 4 holes in the frames on top of the bell. The one I have on my Whiplash is trouble free, with the spider coupler its been on there with the same generator since day 1, now at 742 flights or about 210 hours use. The goblin uses the same start shaft adapter as the whiplash does, and I got the adapter supplied with the one way reversed in it, so it can be included in the kit to make it easy for the user to just swap out their stock unit, and/or just include the start shaft too in the generator kit as some people with the goblin don't even have the start shaft in there -- its optional through Carey.

I gave Joey coupler dimensions, so I believe he can make sure the generator sits low enough not to interfere with the canopy. The most important thing about this mount design is that the start shaft and the motor have to be dead nuts centered with each other, but this is easy for Joey to do with his equipment hence why I asked to see if he could get it done for you guys.

-=>Raja.

[R_Lefebvre]

Well, the design presented is basically a torque arm mount, which is actually pretty common in industrial applications. So, the idea is valid, as long as the details are right, it should work fine and be perfectly reliable.

[rcnut]

I have never used that top start on either of the gassers I own, and dont feel I ever will.

That said I would be willing to try the top option due to the lower parts/cost. Also it would keep it simple.

I've used the top start a couple of times, but prefer the pull start.

I too would be willing to try this type of generator mount! It looks solid…and very simple.

[jc23cl]

Okay : )

Lets try another option.

2mm G10 support plate, 4x aluminium standoff posts.

The thin clutch nut is replaced with a pulley, threaded to the required M15x1. And another pulley on the Gens output shaft.

These are 2M GT3, timing pulleys/belt and should have no problem driving the Gen.

The slots allow the belt to be tensioned. The standoffs are 11mm high and diamter 8mm.

Of course we can do the standard coupling mount, but its Iportant to explore other options first.

Anyway here it is.

P.S. Azalin, love that configuration, the canopy of the Goblin would be too tight to fit a Gen next to the main gear I'm afraid. Great solution on the Rex tho !!!

[rcnut]

Ooh, ooh!!! Pick me, pick me! ...I'll try that design. Looks like it will work rather well.

[Azalin]

Much better.

[brw0513]

Originally Posted by Azalin

Much better.

Agreed.

[Rudy]

I would call that over engineering. You just took a $10-15 mount and turned it in to $50 - 75 mount.


Lets keep it simple.

[fastflyer20]

I like the new concept allowing for a top start.

To experienced generator users - is it an issue that the generator will only turn when the clutch is engaged?

[petercp4e]

Very nice. Keeps the "top start" guys happy, the pull start guys carry on as usual and everyone gets a generator. Looks like a win win to me!!!
Pete <:-}

[carey shurley]

To experienced generator users - is it an issue that the generator will only turn when the clutch is engaged?

this gets to the heart of the "evil" side of generators.

some folks who use them just stop paying attention to the flight packs all together. Don't bother checking them or charging them because they know that if the engine is running, they have power. Used in this way, its just a serious incident waiting to happen.

It is true that you can run a smaller, lighter air pack, but then the extra weight of the charging system pretty much offsets that. Plus you can just buy several flight pack batteries for much less and swap them out between flights.

its purpose should be to keep the pack charge fairly consistent for long flights and/or multiple flights. If you're running an EI system on a shared pack, this becomes pretty important. Since the point is for the model to be flying, don't see why it would be an issue.

as to the cost, you're right this would be a more expensive mount.........BUT....a jewel generator setup itself currently costs more than a stock Zenoah engine does and it is purely an optional item. So I don't think cost is so much of an issue here.