Rumor has it that it was called a "Trauma-hawk" because it was "spin friendly". :-)
-----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Dave Arbogast, CISSP Sent: Tuesday, February 20, 2007 11:46 AM To: KRnet Subject: Re: KR> Thrust Line issues Funny, my instructor called them the "Trauma - hawk" because of the T tail being less responsive to prop wash when you need it the most - stall recovery. Raising the trust-line I would think increases the loads on the upper half of the firewall. Maybe not enough to worry about, but I sure like the idea of more ground clearance for the prop. -dave Colin Rainey wrote: >Don and netters >Something else came to mind the other day when considering the effects of >raised or lowered thrust line. During flight training to become CFI's we >were always told that the reason the Piper Seminole was made with a high "T" >tail as compared to its sister plane the Piper Seneca which had a >traditional tail (and 2 more seats, but that is another story) is because >the Seminole was really ear marked for the training market, and so Piper >wanted the tail in "clean air". This was supposed to make it safer to flight >train in. I am told that the same designer, later worked for Beech and >designed the Duchess, which is why so much of the configuration resembles >the Seminole. > >My point for this post is this: while in most cases planes are designed with >the empennage "in the prop wash", some very successful designs are not. >These planes seem to experience less pitch change due to the change in the >amount of prop thrust over the elevator/stabilator, and the change is more a >function of airspeed/airflow. If by raising the thrust line, one lessens the >amount of prop wash over the elevator of a particular KR2 or S, that builder >may find a nice softening of the effectiveness, without becoming dangerous. >Then again it may favor one side only, causing good nose up authority, but >lose some nose down authority. > >I would also think that if the builder then used a longer prop taking >advantage of the greater ground clearance, he might not have any change in >the behavior of the plane to speak of at all. > >Just some ideas for thought. I was once considering a PSRU or re-drive as >some call them, for my 1915 cc VW original engine. Had I installed that, I >would have been 4 to 5 inches higher. This may be an issue many builders >have contemplated or evaluated. > >Colin Rainey >brokerpi...@bellsouth.net > >_______________________________________ >Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp >to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >Post photos, introductions, and For Sale items to <A HREF=http://www.kr2forum.com/phpBB2/index.php >please see other KRnet info at http://www.krnet.org/info.html > > _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net Post photos, introductions, and For Sale items to <A HREF=http://www.kr2forum.com/phpBB2/index.php please see other KRnet info at http://www.krnet.org/info.html -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.441 / Virus Database: 268.18.3/693 - Release Date: 2/19/2007 5:01 PM
