The International Cessna 170 Association

Naa.... it has a stabilator!

mrpibb wrote:Yeah but the piper was trimmed for slow flight. As for the calender might have to wait for the paint, and wings to come back.

That's fine. As long as I can get the pic before mid-September we'll be fine.

That's fine. As long as I can get the pic before mid-September we'll be fine

You know how them newenglander are, min's are hours, hours are day's and days could be weeks. But to be honest my buddy's been getting slammed with work ever since moving his shop to Hampton airfield. Ironic enough they are 170's.

I'll see if I can get some pics of '49V at some of the summer fly ins this year.

T.

Thanks Tom! Photos of '48s always seem to be in short supply.

For what it's worth, belatedly, here is mine cruising at 110 MPH true; ~1950 lbs; CG ~ 43.3. I sometimes wondered about this also but the plane is rigged correctly so I wrote it off to design.

[img][img]http://img53.imageshack.us/img53/613/11 ... eftmn4.jpg[/img][/img]

Steve

I really respect WD Thompson. Can never hope to have the experience and knowlege he had acquired about this (and other) Cessnas. But I think his description of the tail-rigging on the 170 was an unfortunate choice of words.

The tail of conventional airplanes provides "downward" lift. (It makes a downward force on the fuselage to offset the CG which is forward of the Center of Lift (CL) of the airplane. The Cessna 170 was a development out of the 140...except with a heavier engine and a longer cabin to accomodate a rear seat and baggage compartment. A CG farther forward was anticipated for this airplane....and therefore a greater downward force was anticipated as being required of the tail. (Remember, the early tail had slightly less area than the later tail....and the metal wing was anticipated as being heavier than the ragwing....and with a still further forward CG resulting. On top of that the metal wing got more fuel as well. And...the L-19 was already well in development and it shared common components with the B model tail.... so making an incidence change became an issue of economics.)
The metal wing turned out to be almost 20 lbs lighter than the rag wing (due to no need for internal bracing.) And the CL of the NACA 2400 series airfoil was further aft than the ragwing.
The angle of incidence of the horiz. stabilizer was already set...for the L-19.... it was slightly negative for the 170A/B... and the easy fix was to adjust the elevator rigging.
It may have been that the negative angle of incidence was helpful to the landing of the lighter 170 (as opposed to the wider envelope of the L-19). But I believe it more correct to blame the simple economics of using common production jigs, than to conjecture that a drag-inducing design-change was deliberately and consciously made in order to overcome a fwd CG when lightly loaded.

Man, all you need is a set of wheel pants and that Piper would be eating dust.