---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Sun 03/26/17: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:32 AM - Re: Twisted Yak 52 Airframe (Jean-Philippe Martel) ________________________________ Message 1 _____________________________________ Time: 06:32:35 AM PST US From: Jean-Philippe Martel Subject: Re: Yak-List: Twisted Yak 52 Airframe =F0=9F=98=82=F0=9F=98=8A Le 26 mars 2017 01:54, "William Geipel" a =C3=A9crit : > Pull 10g in the other direction. It will probably twist back. All good. > Tape the charts to the windshield; keeps the sun out and they don =99t blow > away as often. Slide the chart into the crack. > > OR buy a CJ. They have so many issues that you won=99t notice that you=99re > twisted and flying sideways. > > Just a thought. > > On Mar 25, 2017, at 18:09, Roger Kemp wrote: > > Paddles, > You are doing better than me on paper charts. With the canopy cracked I > can't keep them in the cockpit. > Doc > > Sent from my iPad > > On Mar 25, 2017, at 9:47 AM, Mark Davis wrote: > > I don't know if you can twist a YAK52 airframe without running over it > with a Russian tractor, mine has more rivets on it than the USS Missouri. > I've been told two things about YAK 52 airframes, but I can't verify > their accuracy. One, there has never been an inflight failure of a YAK 5 2 > airframe. Two, that the Soviets/Russians design their aircraft such that > airframe failure shouldn't occur before twice the G limit of the aircraft > vs. 1.5 times the G limit for U.S. certified aircraft. Therefore, even a > +5/-3 airframe wouldn't fail before +10 g's, most will stall long before > that or the pilot will be GLOC'd and not know the difference. Early in > their history the YAK Design Bureau obviously saw an issue with the > airframes and performed the modification to raise the limits to +7/-5 g's .. > There are others who watch this list who may chime in the specifics. > > You may be onto something if one aileron has the fabric holes uncovered, > but any drag would more likely be fixed by tweaking the rudder trim tab a nd > putting the ball in the center. Any airflow disruption would more likely > cause a change in the effectiveness of aileron itself by disturbing the > boundary layer. But, that big chunk of wood on the front of the YAK that > the Russians call a V530 propeller creates so much P factor that any chan ge > in power settings or RPM noticeably changes roll trim on my YAK. So I tr y > to trim mine for a typical 70% rpm 125-130 KTAS cruising speed for cross > country flights and live with the slightly out of trim one way or the oth er > aileron control pressures the rest of the time. Otherwise, seek out a > cheap electric trim system or do what I do and make my wife take the stic k > for a few minutes if I'm trying to refold a sectional on a cross country. > I may be the last dinosaur out there without ForeFlight that still keeps a > paper sectional in the airplane....and everywhere I go I have to either > flip the chart or refold as I go from seam to seam.... : ) > > Mark Davis > N44YK > > > *From:* owner-yak-list-server@matronics.com [mailto:owner- > yak-list-server@matronics.com ] *On > Behalf Of *Phillip Salter > *Sent:* Saturday, March 25, 2017 7:36 AM > *To:* yak-list@matronics.com > *Subject:* Re: Yak-List: Twisted Yak 52 Airframe > > Mark, > > You peaked my interest in twisted airframes. I have contacted a few Yak > folks and the common answer, spoke to how aircraft are set up during > assembly, rather than a twist. Of course anything is possible, but twisti ng > a Yak airframe would take serious abuse, and most likely over G. The Yaks > only have 4 deg of dihedral and are neutrally stable for aerobatic purpos es > so it does not take much to change from stabile flight to a slight roll o ne > way or the other. I talked with Yak owner who is an aeronautical engineer > and his suggestion for my plane is to cover the lighting holes behind the > right aileron first. This plane flew mostly hands off when I got it but i t > changed. The fabric covering the lightning holes came off which may be > causing drag on the right wing from turbulence. My aircraft was not an > aerobatic club plane, it was Romanian Military which I was told is a > better or less aggressive service for the Yaks. > > Do you by chance know what actually twists on the Yak airframe? > Measurements may be the answer to find a twist. > > Regards, > > > Phil > > -----Original Message----- > From: Mark Davis > To: yak-list > Sent: Fri, Mar 24, 2017 7:11 pm > Subject: Re: Yak-List: Twisted Yak 52 Airframe > > > With 4 degrees of dihedral, bending one a little might help with > stability! I can tweak trim tabs and get close, but power changes due to > fuel or passenger weight will change it enough that a wing is always goin g > to drop. The Soviets must have stolen the stability characteristics of an > A-4 and applied them at the Yakovlev Design Bureau. They forgot to steal Mr > Heinemann's electric trim system design for the Scooter.... > > Fly Navy, > Mark Davis > > Sent from my iPhone > > > On Mar 24, 2017, at 5:29 PM, PS wrote: > > > > > > Many of the Yaks that came out of Russia after the fall had been twiste d > by the aerobatics clubs. If you can get it to fly straight and level in > cruise, let me know. > > > > I received the above email concerning my Yak. I have been involved and > owned Yaks over 17 years, and never heard anyone mention a "twisted" Yak. > Is there any validity to this? Being an nearly 0 deg dihedral aircraft, i s > a Yak 52 ever totally stable? My aircraft flies great but has a slight ro ll > to the right, so minor I never worry about it. > > > > Regards, > > > > Phil > > > > -------- > > Phil > > > > > > > > > > Read this topic online here: > > > > http://forums.matronics.com/viewtopic.php?p=467584#467584 > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.