logo
Thread Tools
Old 10-22-2019, 04:15 PM
JCFLYR is offline
Find More Posts by JCFLYR
Team Chaos
JCFLYR's Avatar
United States, MI, Mason
Joined Apr 2011
816 Posts
Quote:
Originally Posted by tciranni View Post
I only have two flights on my plane and the CG was fine. I used the Pilot recommended CG. I have not heard of anyone else complaining of CG problems and many others have a lot of flights on their planes. You must have done something different.
I've actually had another guy tell me of the same issue! The only changes were to a lighter spinner and I used J-tec mufflers. Nothing that would have caused such a drastic change. The initial maiden was done with the airframe quite nose heavy, according to specs, and the airplane was extremely tail heavy. If I were actually able to get the plane to the published specs on the maiden this would have been a disaster! I know from these threads that guys have noticed differences in airframes from scheme to scheme. I have been flying for over 40 years and I can tell you with the utmost of confidence, if you fly this airplane at the recommended CG, be ready for a handful!
JCFLYR is offline Find More Posts by JCFLYR
Reply With Quote Quick reply to this message
Sign up now
to remove ads between posts
Old 10-22-2019, 04:39 PM
Mr Cessna is offline
Find More Posts by Mr Cessna
Registered User
Mr Cessna's Avatar
Japan, Saitama, Kawajima
Joined Jun 2019
29 Posts
I’ve read about the elevators needing to be aligned just right, could this been the problem?
Mr Cessna is offline Find More Posts by Mr Cessna
Reply With Quote Quick reply to this message
Old 10-22-2019, 06:17 PM
JCFLYR is offline
Find More Posts by JCFLYR
Team Chaos
JCFLYR's Avatar
United States, MI, Mason
Joined Apr 2011
816 Posts
Quote:
Originally Posted by Mr Cessna View Post
Iíve read about the elevators needing to be aligned just right, could this been the problem?
I'm not sure that would contribute to CG problems. I did not have any elevator issues other than having to cut the rudder control horns down after installation because they restricted elevator movement during deflection.
JCFLYR is offline Find More Posts by JCFLYR
Reply With Quote Quick reply to this message
Old 10-23-2019, 07:37 AM
jharkin is online now
Find More Posts by jharkin
Registered User
jharkin's Avatar
United States, MA, Holliston
Joined Jul 2007
652 Posts
If you measure the wings and calculate the %MAC that Pilots suggested CG comes out at, what did you get?

Maybe they calculated wrong... I wouldn't be surprised if there are builders out there who just install the same components that Pilot did and assume the CG will be right without actually weighing/measuring, and just got lucky that they ended up more nose heavy than the prototype.

As far as the stabs, I agree misalignment wont cause the same symptoms as a bad CG... if they are off side to side it will act like the aircraft is out of aileron trim and if they have +/- incidence it will act like it needs a lot of elevator trim.



... BTW, this discussion prompted me to go searching for it, and surprisingly somebody resurrected the old Geistware online CG calculator!! To figure for a bipe you need to calculate both wings and average them


http://www.willingtons.com/aircraft_...vity_calcu.htm
jharkin is online now Find More Posts by jharkin
Reply With Quote Quick reply to this message
Old 10-23-2019, 10:24 AM
JCFLYR is offline
Find More Posts by JCFLYR
Team Chaos
JCFLYR's Avatar
United States, MI, Mason
Joined Apr 2011
816 Posts
Quote:
Originally Posted by jharkin View Post
If you measure the wings and calculate the %MAC that Pilots suggested CG comes out at, what did you get?

Maybe they calculated wrong... I wouldn't be surprised if there are builders out there who just install the same components that Pilot did and assume the CG will be right without actually weighing/measuring, and just got lucky that they ended up more nose heavy than the prototype.

As far as the stabs, I agree misalignment wont cause the same symptoms as a bad CG... if they are off side to side it will act like the aircraft is out of aileron trim and if they have +/- incidence it will act like it needs a lot of elevator trim.



... BTW, this discussion prompted me to go searching for it, and surprisingly somebody resurrected the old Geistware online CG calculator!! To figure for a bipe you need to calculate both wings and average them


http://www.willingtons.com/aircraft_...vity_calcu.htm
Yes sir that is correct calculating the CG for a biplane is different then with a mono-wing. I just want people to be aware of a possible problem with all or some of the 40% bulldogs. Pilot RC has been notorious for mismarking CGs in their airfames. I have the PRC 31% edge 540 V3 and there are two laser marked center of gravity marks in the airframe and both are wrong. There was an entire thread dedicated to it and fortunately I was able to get some good information from other folks as to where the correct CG actually was before flying the aircraft. there were a couple of guys that actually lost the airframe because they used the laser marks.
JCFLYR is offline Find More Posts by JCFLYR
Reply With Quote Quick reply to this message
Old 11-17-2019, 10:00 AM
cbcalhoun is offline
Find More Posts by cbcalhoun
Registered User
United States, OH, Newark
Joined Oct 2011
45 Posts
Has anyone 3D Printed some custom baffles?
cbcalhoun is offline Find More Posts by cbcalhoun
Reply With Quote Quick reply to this message


Quick Reply
Message:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools