Engine swap - wing sweep

[GuppyWN]

If you swap from a Lycoming to a Rotax do you take the 1 degree of forward sweep out of the wings?

[PapuaPilot]

I believe you would need to change the sweep on the wing due to the significant change of weight.

I'm not sure what needs to be done to accomplish this. When the sweep is initially setup you drill through the fuselage and wing spar, which has a doubler inside. I would guess that you would leave the fuselage hole as is and redo the hole in the wing spar. Most likely you are going to have to install a new inner doubler on the spar.

It would be best to call the factory, unless someone else has already done so.

[peanut]

I’m reviving this thread from the depths. I too would like to know.

[jmodguy]

I would say that you would need a new set of doubters and those would have to be match drilled to the existing holes in the spar for the rivets. The bolt holes would be drilled in the new location on the new doublers to remove the sweep. Not sure if it would be advisable to weld the outer edge of the hole in the spar.
Once that is done, recheck all the rigging per the manual.
There may be other options but this seems most straight forward to me. Your mileage may vary!

[avidflyer]

Before I started to remodel the wings, I would get the calculator out and start doing weight and balance calculations. Maybe some weight in the tail would take care of it. JImChuk

[peanut]

No for sure. I’m just trying to learn as much about these birds as I can.

[av8rps]

I recall an experienced Kitfox builder once sweeping the wings forward on a Rotax 912s powered Model 6 just so he could make best use of the 150 lb baggage capability. So I agree with a previous poster to check weight and balance numbers to find out how that wing sweep really affects things. Changing the sweep back to stock could be a big project that you may not even need to do.

[Planesmaker]

Sweeping the wings forward is so more weight is balanced at the front not in the rear! So forward swept wings with rotax will have less baggage capacity.

[Flyboy66]

I see a couple problems here, BUT I am not an expert, so I would recommend what a previous poster said and contact the factory. By simply changing the engine, the CG is going to move aft. If attempting to redrill the hole and mount new doublers, the hole will move closer to the end of the spar, maybe too close. Not sure how the old doublers could be removed along with the hysol. Adding weight in the engine compartment might be a possibility, but the arm is so short (even shorter than the arm of the old engine) that it would take more weight than the difference in weight of the old engine and the Rotax.

Anyone who sweeps wings forward is going to reduce baggage capacity, not increase it.

The wings are swept forward with the Lycoming engines because they are heavier and the weight of the engine moves the CG forward near, or outside the forward limit.

Perhaps there is someone out there that went (or wants to go) the other way and has a set of wings that you could trade for.

[jmodguy]

To remove the doublers is relatively simple. Drill out the rivets and heat up the parts with a high temp heat gun. The hysol will break down and you can pull it off with pliers etc.

[av8rps]

Oops! I guess I had a brain fart. It was John Kings Model 6 that I was thinking of. But after re-reading his Kitfox of the month write up, he swept the wings back, not forward, in order to increase baggage capability.

If interested, he explains what he did in detail at:

http:// http://www.teamkitfox.com/Forums/showthread.php?t=355