Hi!

I'm almost finishing a Aviomodelli Cessna Skymaster, and I'm now installing the engines.

The plane is not heavy, in fact, it's very light. So, I 'll flight test it with a OS 46 FX in the front and a OS 46 FX-Heli in the back.

How may I install both engines, due to the torque? How much anti-torque would I need?

Thanks

Eduardo

if you view the engines from either directly in front, or directly behing the Skymaster, they are rotating in opposite directions and will cancel the torque from each other...the heli engine may develope a tad more, but it probably won't be noticeable....

Yes... I know the engines cancel the torque from each other, but if one of them shuts off??
Shouldn't I give the engines a little anti-torque, so the plane could still fly safely with only one engine?

Thanks

Eduardo

Hello enogueira
As far as I know, in the USA what you describe as "anti torque" is not used. What do you adjust, and how, for anti torque for the front engine? I flew a pusher/puller SPAD plane of my own design, equipt with two .28 Magnum engines. Like your plane, one engine was in front of the wing and one was in back of the wing, with a pusher prop. There was an interesting gyroscopic effect from the engines running in different directions. The plane would not spin very well because of this, nor make a hammerhead stall. I never saw a peoblem when one engine stopped and frequently did not know which engine stopped. Buena suerte con su avion. No se Portugues.

With centerline thrust, I doubt it would be anything to worry about....

Hello enogueira
I now believe that by anti torque you mean right/left engine angular offset. That is only used on a conventional twin or multi engine plane. When the engines are mounted in-line, like on your plane, no side thrust is needed. Do you have photographs of your plane that you could post here? I always liked taking off with only one engine running on my pusher/puller. Here is a photo of it:

I was talking exactly of the engine angular offset. A little to one side and a little down.

The engines are allready isntalled and they are both at 0º. Hope this will work fine.


Here are some pics. I willl take a few more now, with the lights and engines installed.
The test flight will be tomorow... If all works fine, then it will be time to paint and add interiors and antennas, and all the scale details.

Hope you like it!

Hello enogueira
Nice photos. I recall now that the rear engine easily overheats when running on the ground. I tried to get into the air withing 30 seconds of starting the rear engine. If I had to adjust the rear engine I uaully changed that prop to a standard but identical prop so the engine would not overheat.

Hey Enogueira,
That skymaster is sweet! The torque effect that I believe you are referring to is not torque. Airplane engines torque in the axial or roll axis. The effect that I think you are referring to is "P" factor. That is handled by side thrust. I agree with Wayne that side thrust will be a minimal concern for you. However you might benefit from a little down thrust on the forward engine. Again, that is a sweet airplane. Good luck.
Skip D

Hello!

I'm happy you like my new plane!

The flight test is waiting for better weather... It's raining almost for a week...[]

But this way I've some time to be in the workshop, and so, the interiors are almost done! Then it's time for a finishing paint and up to air...

Eduardo

Eduardo, You are a TRUE CRAFTSMAN!!!!! I think I am a good pilot. If I had your building skills I'd be set. Can't wait to see the final pictures and hopefully video. Good luck. Skip D

As long as we are talking about Skymasters, here is a couple pic's of my Hostetler 337. I am jus finishing up with the trim on the midsection and wings. Using two DA-50's........

Hi!

The flight test was done!

The plane is wonderful! Now it's time to re-think the engines. Maybe a 61FX in the front... let's see...

Here is a nice video. Hope you like it.
[link=http://www.youtube.com/watch?v=x8wYw4X2VFM]Skymaster video[/link]

Eduardo