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Thunder Power RC . Mikado Modellhubschrauber . GrandRC

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Gohbee Aviation Stinger 30-90 > Gear ratio for Stinger 90
 
 
Dino17
Heliman
Location: Kalamazoo,MI ,USA

Hi ,can anyone tell me what gear ratio does Stinger 90 heve? And what gear raio is possible to be used on Stinger 90 .Is there way to have something lower than 7:1 or around 7:1?
05-29-2007 Over year old.
 
 
Portblock
Veteran
Location: Van Nuys, CA

There is a 10 tooth and an 11 tooth pinion, and for main gears you have 90, 91, 93,95

Your ratio range is from 8.19 to 9.5

7.1 is realy low, and would put your engine outside its powerband witht he YS and OS engines. At 1800 head speed would put the engine at 12,780

.....
05-29-2007 Over year old.
HOMEPAGE  
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

The 90 ships with a 8.27:1 gear ratio installed for the OS 91's and comes with an extra 93 tooth gear to get you to 8.45:1 for the YS 91.

7:1 is in the ballpark if you are looking to convert to a gasser.
There is a 12 tooth available from Gohbee and will get you down to a 7.5.
I am working on a gasser conversion at the moment and have a 13 and 14 tooth gear to test with. These two gears are the only ones on the planet at the moment that I know of so don't ask where to get one, I made them in my basement and it was not fun or cheap to do.


Jeff Borowski
Gohbee Field Rep
0133TD
05-29-2007 Over year old.
HOMEPAGE  
 
 
Dino17
Heliman
Location: Kalamazoo,MI ,USA

Yes ,I am going to do gasser and looking way to get lower gear ratio.You disappointed me .Can't be used pinion from other brand heli?I know that Predator has 14 teeth pinion ,but somebody told me that predator's main shaft is 8 mm .Can you give me more information about your "home made" pinions? How did you make them?
05-30-2007 Over year old.
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

For the 14 tooth gear I was able to purchase a piece of gear stock from Stock Drive Products search for part number A 1C29MY10014 and then it was just a matter of turning the new pinion out of that on my lathe.

Making the 13 tooth pinion is not as easy.
I could not find a source for 13 tooth, module 1.0 gear stock.
Sooo, I just "had" to go out and buy a horizontal milling machine, an indexing head, and the correct cutter for the 13 tooth gear and make mine from scratch.

The pinion gear in the Stinger 90 is the same as the pinion gear in the Raptor 90, so if you can find a source for 13 or 14 tooth Raptor gears, they will fit the Stinger. I do not know of a source, that is why I made my own.


Jeff Borowski
Gohbee Field Rep
0133TD
05-30-2007 Over year old.
HOMEPAGE  
 
 
Dino17
Heliman
Location: Kalamazoo,MI ,USA

Your 13 tooth pinion is very expensive .I think 14 tooth can work for me . 91/14 = 6.5 gear ratio ,this sould be good for 231 engine.Unfortunatly i can't make even this one.Don't have any machines for that purpose.I tried to find 13 and 14 tooth but could not. Thunder Tiger doesn't make any like that.Thank's
06-01-2007 Over year old.
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

Yes the 13 tooth was expensive, but I got a lot of new toys out of the deal so that makes it worth it.

If this Stinger Gasser project of mine works out, It will be available as a kit from Gohbee, Including whatever gears I settle on.
Do not hold your breath waiting for this as it is not the top project happening right now, the gasser kit is at least a year out yet.

There was a thread a couple of years ago of a Raptor 90 gasser conversion.
http://www.runryder.com/helicopter/...top=1180704178.
You may get some useful info here.


Jeff Borowski
Gohbee Field Rep
0133TD
06-01-2007 Over year old.
HOMEPAGE  
 
 
Dino17
Heliman
Location: Kalamazoo,MI ,USA

Too long time -year and more.I chekted everything in RR .There are a few projects.Some guys tryed Webra and BME engins but they have bad performance.Only Zenoah is reliable.It is heavy but good .There is way this engin to be put on Rapter ( Stinger ) heli .The only problem is gear ratio. Nobody make low ratio gears.Honesly if I can decide this ,I could try to make a gasser. How long do you need to complite your project ? Can put some pictures.
06-01-2007 Over year old.
 
 
wheelman
Senior Heliman
Location: Kirkfield, (Coboconk), Ontario, Canada

Quote 
Sooo, I just "had" to go out and buy a horizontal milling machine, an indexing head, and the correct cutter for the 13 tooth gear and make mine from scratch
Ok Jeff now I KNOW you're not completely sane! I previously had my doubts, but this pretty much confirms it! I've thought of this gasser idea myself from time to time. I just assumed there was some type of gear out there somewhere that could be made to fit. Somehow though I doubt you'd have gone through all that trouble if there were. Best of luck with the project! I'm looking forward to saving the $$ on fuel.
06-02-2007 Over year old.
HOMEPAGE  
 
 
Dino17
Heliman
Location: Kalamazoo,MI ,USA

Tell us about these gears .What ideas do you have?
06-02-2007 Over year old.
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

Quote 
Ok Jeff now I KNOW you're not completely sane! I previously had my doubts, but this pretty much confirms it!

You are only first confirming this now? You should hear what my GF has to say about this hobby and my "needs".

In the link that I posted above there is info including gears that will work to make a one off conversion for yourself. I am working on this more as a potential kit for Gohbee to produce. So I obviously can not just use parts from Bergen and Century, but you can.


Jeff Borowski
Gohbee Field Rep
0133TD
06-04-2007 Over year old.
HOMEPAGE  
 
 
wheelman
Senior Heliman
Location: Kirkfield, (Coboconk), Ontario, Canada

Quote 
. I am working on this more as a potential kit for Gohbee to produce. So I obviously can not just use parts from Bergen and Century, but you can.
Yes, I hadn't even thought about that aspect of it! I think I'll do some more reading, and take a more serious look into exactly what it takes to get into this. I would really like to experience the economy of "pump" gas. From what I've seen a decently set up gasser has more potential than I know how to use, so it would be a great way to get tons of stick time in, for a fraction of what it would have cost for the same stick time on a nitro .90. I fly my .30 a lot right now just for the economy factor. I'm getting at least 30 min. on a tank using an OS .32 but at the cost of a lower power to weight ratio The .50 has great power but a fairly short flight time. I LOVE the power of the .90 but man can it EVER suck back the fuel, and a much shorter flight time too. For me the most important issue currently is stick time. I need as much time in as I can get to improve my skills. With a Gasser I'd be getting a good amount of power to weight, cheap fuel, AND long flight times. Sounds like a winner to me!
06-04-2007 Over year old.
HOMEPAGE  
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

You will be pleasantly surprised to find that a gasser has a lot more power than a 90 on 30%. Check out the link that I posted above, he lists sources for all of the parts from various manufacturers that he used to build a R90 into a gasser. The exact same setup should work for the Stinger 90.

I really liked flying my gasser and want to get this new Stinger gasser done, there are just to many other priorities in the way right now.
I may even resurrect my old xcell gasser (since no one is interested in buying it cuz it was to low of a price, go figure) just to be back to flying a gasser.
A gasser flies somewhat different from a nitro ship due to the extra weight.
It is very smooth and solid feeling in the air. Yet with the right setup it will still rock and roll. It just takes a little longer to get up to speed or stop and change directions, but has a higher top speed.
It is kind of hard to explain.


Jeff Borowski
Gohbee Field Rep
0133TD
06-04-2007 Over year old.
HOMEPAGE  
 
 
wheelman
Senior Heliman
Location: Kirkfield, (Coboconk), Ontario, Canada

I found some vids a while back of gassers flying. I was very surprised by the forward speed! They seem really fast. I understand what you're talking about regarding the extra weight. I'm partial to heavier machines due to the extra stability, and they do seem to feel more "solid". I'm sure the gassers will perform "stops & starts" , flips & rolls slower than the nitro birds. I think this may help me hone the precision of my flying. I sometimes like watching 3D performed at a slower rate. It makes it easier to see what is going on. More time to "take it in". When the manouvers are performed at blistering speeds, the speed helps to mask errors. The next manouver is already beginning before you get a chance to analize the error that just occured. Now instead of analizing the error, you're watching the next manouver being performed. I'd like to try slower manouvering. The gassers should do that "naturally" evan at it's full cyclic ability.
Funny thing though I suppose I never really gave it much thought, but thinking about it now I guess I figured they did not have a lot of power. After giving it some thought, that's ridiculous! Those motors are very capable of much, much more power than a good .90. The more I ponder this, the more I want to convert!
06-04-2007 Over year old.
HOMEPAGE  
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

Depends on how big of a gasoline engine we are talking about. Anything under 40cc gasoline has a equivlent or superior nitro counterpart. Gassers do have better torque but have lower RPM and are alot heavier. That is just my experience in the airplane world. Wich is why most people say that if you are going to go gas, go 50cc and above. I am not sure how these figures pertain to helis since i have only done nitro helis.
06-05-2007 Over year old.
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

True anything under 40cc has an equivalent nitro size.
On a plank that is very easy to accommodate since all engines mount to a flat firewall with the addition of the appropriate engine mount. bigger glow engines also turn lower rpm requiring all of the same mods as a gasser.

To put a nitro engine that is bigger than a 90 into a heli will require the same amount of redesign work as putting in a gas engine. You still have to make your own engine mount but now you will need to make a fan, gears, clutch, cooling shroud, etc.
The gasser engines used in helies are either a 23 or 26 cc engine, a 91 is 15cc.

The BIG nitro engine will also suck lot of fuel. Plan to get a quart of fuel on there to get a 10 minute flight or get used to 3-4 minutes from the stock tank. a gasser will run for 15-20 minutes on an 8oz tank, or a half hour + on the stock tank.
One of the stated goals is lower cost flight time, a big glow will not get you there at just 4 flights per gallon of expensive fuel.

On my project list is stuffing a 23cc (1.40 CID) glow engine into a 90 size ship. (why? because I can) These are the same issues I am running into with a bigger engine whether gas or glow.

I say do some more research into how to do it and then if you feel that the mods required are within your capability, then go for it, I think you will like it.

Feel free to ask questions, I'll be glad to help you out with any info or ideas I can give.


Jeff Borowski
Gohbee Field Rep
0133TD
06-05-2007 Over year old.
HOMEPAGE  
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

I have hear about the insane fuel economy with gasoline engines. Interesting because you could subtract the 8oz or so of fuel you take away from the total net weight. I bet it narrows that gap alot. I have been told buy many people in the airplane world that once you get above 120 size glow, fuel costs are just rediculous. Plus, i have been facinated in the differences in the relationshipes between"weight/power" on heli's than on planes. While a 25cc gasoline can not compete with a 15cc glow in the airplane world because of weight, they seem to be very competetive in the heli world from the videos i have seen.
06-06-2007 Over year old.
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

Not only are you carrying less fuel but it is a lighter fuel as well.
30% glow fuel is around 9lbs / gal and gas is around 6 lbs / gal.


Here is a comparison I did a while back while bored at work


Jeff Borowski
Gohbee Field Rep
0133TD
06-06-2007 Over year old.
HOMEPAGE  
 
 
Dino17
Heliman
Location: Kalamazoo,MI ,USA

FLYINHOOL, how is your project going .Did you have some test flies ?
06-16-2007 Over year old.
 
 
FLYINFOOL
Veteran
Location: Cudahy, WI

My Gasser project is not a top priority so it only gets a little done here and there. Unfortunatly it is a long way from flying.


Jeff Borowski
Gohbee Field Rep
0133TD
06-17-2007 Over year old.
HOMEPAGE  
 
 
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Gohbee Aviation Stinger 30-90 > Gear ratio for Stinger 90
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