Raptor 50 Upgrade questions

[jakesvdm]

I am in the process of upgrading my 30 to a 50. I have compared the two manuals and wrote down all the differences. My question is related to the gear ratio. The 30 has a 9 tooth pinion and 86 tooth main gear, which gives us a 9.56:1 gear ratio. The 50 has a 10 tooth pinion and 85 tooth main, which gives us a 8.5:1 ratio.

Before we go further. Lets discuss my skills a bit. I have just moved in to forward flight and can do circuits. I have also started with stall turns. I can also do auto's. And that is basically what I can do. My next step is to try rolls and loops. With this in mind.

Why do I need to change the gear ratio ? I'm using a OS 50 engine (with TT performance pipe), which produces 1.8 hp @ 18000 rpm with a maximum usable rpm range of 20000 rpm (according to the manual). With a gear ratio of 9.56 (using the 30 main and pinion), with an engine speed of 18000 rpm the head speed will be 1882 rpm (calculated). And with an engine speed of 20000 rpm, the head speed will be 2092 rpm.

Can I fly the heli like this for a while ? or is it absolutely necessary to change the gear ratio to 8.5:1 (the 50 pinion and main) - considering my skills ? I.e., if I fly like this will I blow the motor or damage the heli in any way ?

Inexperienced as I am, it sounds like it could work. All I have to do is watch the throttle and pitch curve closely.

[vandelescrow]

My first Raptor is a 30 with the 50 upgrade. I have this heli in a scale fuselage (funky 50 airwolf). I flew with the 30 gear ratio for some time but started to have over heating issues (os50 hyper). I figured if I switched to the 50 gear ratio, the engine can run at a lower rpm while maintaining the same headspeed, thus reducing engine temp. It worked.

Yes you can use the 30 gear ratio, I would say plan on changing them eventualy, as your skills get better you will want a higher head speed to push you through the more advanced maneuvers. Also, If your head is spinning a higher rpm when initiating an auto, they are much easier.

[BarracudaHockey]

Will it work? Yes.

Would I change the gears? Yes.

[Ah Clem]

I went from a Raptor 30 to a 50 via the conversion kit.

The kit came with 8.5:1 gearing.

Based on recommendations from this forum, I have changed gear ratios again to the optional 8.7:1.

I prefer this ratio, the ship is pretty much unboggable (bearing in mind I am more a an aerobatic flyer and not a hard 3D flyer).

[awr]

It will work if you use a governor but your engine won't be running in the power band it was designed for as the 9.56:1 gearing in the R30 v2 was set up to allow a .30 class engine to turn 550mm blades with minimal head bog. When you use a .50 class engine to turn
550 blades at that gear ratio you're going to have problems with your engine over-reving every time you unload the head.

If you do nothing else, change the gearing to either 8.5:1 jor 8.7:1. This will put your engine in the proper power band and will also give you a constant driven tail for autos as
the R30 v2 does not have a constant driven tail.

The instructions that come with the conversion kit suggest several setups, one of which is keeping the R30 v2 tail-boom and blades while changing everything else.

Hope that helps.


Wayne