Wing Extensions

[bobthebowler]

Hi everybody,

I would like to know the effects of MTOW is with adding wingtip extensions onto a light aircraft.

Not winglets, not fences, just an add-on extension of about a foot or so to make the wing longer.

[John Farley]

I would suggest that will depend on what determines the MTOW of the unmodified aeroplane.

For example if that was determined by wing structural strength in bending then it could reduce it. On the other hand if it was to keep the stall speed below some certification limit then it would improve. The question is not as easy as it sounds - but you may know that already!

[rigpiggy]

look here
Wing-X Stol (http://www.wingxstol.com/)

I think any upgross has to be fuel in the tiptanks though I maybe mistaken though

[barit1]

An aftermarket kit did this for the old Republic SeaBee; but I'm sure a thorough structural relook at the whole wing and strut was part of the job.

[Engineer_aus]

I did a wingtip extension on a 182 to increase the MTOW 100kg

[barit1]

That indicates, of course, that the basic 182 has plenty of structural margin. You have increased the loading, AND moved the spanwise center of lift outboard, and still met structural requirements. Impressive work by Cessna!

[Jamesel]

Yes, it depends on who is making what assumptions. The Beech 18 had a STC to increase gross weight by clipping the wingtips to reduce the wing bending moments, and there were many more which allowed you to increase the gross weight by - among other things - putting bigger wingtips on to increase the wing area for more lift! :hmm:

[jackharr]

Many gliders have choice of wingtips depending on the category under which they fly.

Eg the very popular LS8 can be flown in 15 metre mode (small wingrtips) for 15 metre competitions or in 18 metre mode (larger wingtips) for 18 metre and Open class competitions. Different max weight limits apply.

Jack

[Tinstaafl]

PA60 Aerostar has a mod that increases MTOW with a wingtip extension.

[Trolltuner]

That indicates, of course, that the basic 182 has plenty of structural margin. You have increased the loading, AND moved the spanwise center of lift outboard, and still met structural requirements. Impressive work by Cessna!


Impressive indeed! Now, having said that, they could have done their customers better in some cases. By that I mean Cessna increased the 182's gross on several occasions (strictly by analysis) but didn't allow "already sold" 182s the benefit. An example: For the 1981 182R model, MGTOW went from 2950 to 3100 pounds (1340 to 1409 kg). There were NO structural changes made to allow this, just engineering paperwork. But there was no opportunity for over 4000 owners of STRUCTURALLY IDENTICAL 182P and 182Q (1972 - 1980) models to benefit. :ugh:

Today there is, only because an aftermarket STC (paperwork only) does for the 182P/Q what Cessna did for the 182R. Don't ask me how I know this. :)

The Wing-X wing extension mentioned earlier is certainly a great STC for some of the earlier airplanes, but it requires structural mods and costs money.

Can the 182 GW go beyond 3100 lbs? From a true certification standpoint, probably not. I believe it has to do with a requirement regarding asymetrical wing loading. (Float equipped 182s are a special case). On a "Special Flight Permit" they are indeed allowed up to 130% of 3100 with certain operating limitations, but that's a special case.

So, as barit1 correctly points out:

...the basic 182 has plenty of structural margin.


Cheers,

Tom