View Single Post
  #99  
Old March 15th 09, 02:56 PM posted to rec.aviation.soaring
ZL
external usenet poster
 
Posts: 51
Default motorgliders as towplanes

Mike the Strike wrote:
To clarify some more - we tow behind a Pawnee using a 120-foot rope
and my Discus 2 has a nose hook. On tow, the Discus has a notable
nose-up attitude, so the 20 degrees I report is the apparent angle
from my seat. I am positioned immediately behind the towplane just
above the wake. I did have one tow last year in which I was unable to
maintain low tow and had to release.

The pull of the towrope can exert a moment if the force vector is not
aligned with the center of mass of the glider.

The catenary depends on the weight of the rope, but is very notable.

Mike

I would bet you are in the top of the wake, not just above it. Matches
the symptoms. I have done the same thing since I like to fly very close
to the top of the wake. If you fly to put the towplane the same place on
the canopy (not uncommon in mountainous areas with no well defined
horizon), a slower tow speed will have you riding low and in the wake.
Guess how I know. Flaps really help here.

By all the reports I've read on the D2, seeing the towplane from normal
high tow position below about 65 kts is a problem. So going to a little
higher tow position may not be a sane option.

Your shortish tow rope may exacerbate this since you will need to be
higher to be above the wake, the wake will be stronger and the angles
will all be exaggerated compared to a longer rope you may well be used to.

The best option may indeed be more speed on tow. Or get some stinking
flaps

-Dave