Found another one

[coosbaylumber]

Found another one

I had brought this up quite some time ago, and I am wondering....

I am re-doing the plan for an old-timer model A/C again, it is a Big free flight, powered by a Brown Jr. that had originally been drawn and flown circa 1940.

Again, this one has un-equal wingspan. The right wing is a bit bigger than the left one. Only by 1/4 inch to 5/16" this time.

But, was this one of the theories in 1940 that allowed the Brown Jr. (a notoriously under-powered engine) to be installed with zero right thrust and no downthrust?

Seems that if a Model was introduced in 1940, it had a Brown Jr. and one bigger wing.


Wm.

[nmasters]

I don't know about models but some Italian WWII fighters had one long wing

[coosbaylumber]

I never heard about the Italians before.

But was informed some time ago, that the German's were altering a few of their gliders in the 1930's. Perhaps to releive stick pressures?


Wm.

[JetPlaneFlyer]

If the difference is only 1/4" then could it just be down to distortion in printing the plan?... It's not unusual on older plans that are second, third or later generation copies to see considerable distortion.

Personally I'd build them the same length anyway. for me there is something that would just not feel 'right' in having asymmetric wings.

Regarding the comment about German gliders.....why would you want one wing longer on a glider where there is no torque to worry about?

Steve

[Brandano]

Some Italian planes had uneven wings to balance out the prop torque effects. It might not look right, but they trimmed better that way. One thing to consider is that while the WW2 Italian planes were generally underpowered and undergunned, they were usually extremely well behaved in flight.
[edit:]
here's some example: the Macchi C200 C202 and C205. This is a page about the C202, check out the 3 views:
http://www.aviastar.org/air/italy/macchi_c-202.php

[JetPlaneFlyer]

The link to the Macchi fighters backs up something i was thinking about earlier... Which wing should be longer?

The prop rotation on the Macchi is anti-clockwise when viewed from front, this is the same as conventional model plane props.. Yet the Macchi has the left wing longer wheareas Wm said his model plan had a longer right wing :confused:

I think logic is on the side of Macchi; i.e. the extra lift of the longer left wing would help counter prop torque. Rudder offset would look after any left yaw tendancy.

Not sure if this reinforces my suggestion that the wing panel length difference on the model plan is down to distortion?.. Or maybe the model designer got a bit mixed up as to which wing to make longer?

Steve

[Brandano]

or the plans are made to build the wing over it upside-down? What shape do the ribs have in the plan?

[BMatthews]

Old timers generally flew right hand circles in the glide. It could be argued that a longer inside panel would help provide a bit more lift to counter any tendency to fall into a spiral dive. However on a big Brown Jr powered model a difference of only a 1/4 to 5/16 inch is so small as to be insignificant. Any effect would be lost in a host of other typical building inaccuracies.

Nope, I'm voting for paper or printing distortion along with JPF. Depending on the origin of the plan you've got the distortion may be large scale photocopier related (a very typical issue even on the flat bed style copiers) or some moisture or humidity related distortion of the original print that you either have or that was used to make copy.

Either way unless you're designing this to be a free flight model then you'lll want equal sized panels in any event.