flyby50

Hello, a plane that i have ,has the engine mounted 1/4 inch to the right, when the guy built it he had the cross lines perfect on the firewall but when he mounted the engine mounts for some reason they ended up 1/4 inch off to the right, can i fly it the way it is or should i redrill the firewall with a new mount, any info would be helpful, thanks.

RCKen

My Feedback: (9)

Most planes are built like this. It helps counteract the torque of the engine. It's perfectly normal and there is nothing to worry about.

Ken

flyby50

Ken, thanks for the reply, i'm not talking about right thrust, if you stand in front of the plane the spinner is not centered in the cowl its off to the right, thanks... i guess the engine is not centered with the center thrust line of the fuse, i hope this helps...

RCKen

My Feedback: (9)

Hmm, ok. What plane is this??

Ken

tstotts

that is a common method in mid sized planes. it does effect thrust.

flyby50

Ken this is a older sig skybolt, thanks.

flyby50

Troy, i never saw this before, it threw me off. The plane is a sig skybolt, bi-plane, maybe someone had one and can let me know if this is set-up right, thanks for the reply...

CoosBayLumber

My Feedback: (1)

Many of the older model aircraft used a combo of engine offset and angled engine thrust. Was discovered about 1962, and used on the larger aerobatic types. It did little benefit for every day fliers. Perhaps the previous owner was using the Skybolt for aerobatic purposes and thus did the simple modification.

But yes. It was used. A now obsolete concept.

Wm.

flyby50

Wm, thanks for the info, i'm glad i asked before drilling more holes in the firewall, so i guess its ok to fly, thanks to all who could help, good information is priceless..... flyby50

ArCeeFlyer

My Feedback: (1)

I have a Great Planes Combat Mustang and they have the engine mounted to the right (plane's left side) just a bit in order to help put the tip of the spinner close to center with the built in right thrust. This also helps with the lateral balance.

Edit: Oops, scratch the lateral balance help, since this engine is inverted, and the muffler is on the plane's left side, it actually makes it a little worse, as I did end up adding a little lead to the right wingtip. If it was upright with the muffler on the plane's right side, it would help in this case. It all depends how heavy the muffler is verses how much weight of the engine is angled to the right whether it helps much or not.

CoosBayLumber

My Feedback: (1)

My old F.A.I. airplane has an 1/8 inch Port side offset, two degrees down thrust, and one degree to right. According to original designer, this wasn't something just thought about, but had to be experimented with in order to get optimum.

The offset engine concept was discussed a good two years ago at teh Aero forum.

The old timers used to build one wing half a bit longer (1/4" to 1/2") to the opposite side to correct some of the turning tendencies under full power. Another obsolete concept.

Wm.

flyby50

Wm, my skybolt has its engine mounted about 1/4 of an inch to the right--the planes passenger side, i'm not that good of a flyer to know what this is going to do, is this something i have to worry about, thanks again to all....

Tired Old Man

My Feedback: (1)

Just go fly it. It won't matter enough to bother with. If it really bugs you then remove the engine and fill the original holes with a wood dowel of the same diameter as the hole. If needed drill out the hole until you have a size that fits a standard sized dowel. Glue them in and re-drill for the new location. Same number of holes as before and the old ones are as strong as a solid firewall.

flyby50

Thanks for the tip, i'm going to leave it alone and see how she flies, thanks to all, flyby50....