Pull Vs Size

[Motorman]

How much does your plane pull? I have a 575 sq in ThunderGazer that has good line tension but doesn't really pull. I can fly it all day. I have a 630 sq in Humongous that pulls kind'a hard and it's a bit distracting. After a few flights it starts to wear down my forearm. I want to build a full size Thundergazer but I'm worried that I will have trouble flying it if it pulls too much. I want to go full size because I think there will be some performance advantage but my smaller plane flys pretty good. Just wondering if it's worth it to build a bigger heavier plane and deal with the extra pull.

Thanks,
MM

[Randy Cuberly]

How much does your plane pull? I have a 575 sq in ThunderGazer that has good line tension but doesn't really pull. I can fly it all day. I have a 630 sq in Humongous that pulls kind'a hard and it's a bit distracting. After a few flights it starts to wear down my forearm. I want to build a full size Thundergazer but I'm worried that I will have trouble flying it if it pulls too much. I want to go full size because I think there will be some performance advantage but my smaller plane flys pretty good. Just wondering if it's worth it to build a bigger heavier plane and deal with the extra pull.

Thanks,
MM

There are a number of factors that determine how hard a CL airplane pulls.  Size really isn't one of them except that larger airplanes tend to weigh more.
The main determinants to how hard the plane pulls is weight, speed, and line length.  There can be other factors like CG location (a nose heavy airplane will pull harder than one that is properly balanced) but they typically do not affect pull as much as those.
Fuselage side area can also affect how much pull is felt at the handle particularly downwind.
Line rake also affects pull but can easily be adjusted to mitigate that  which is unwanted.

A full size stunter like the Thundergazer should weigh somewhere between 55 oz and 62 oz.  Anything in that weight range on 65 to 67 ft lines at about 5.2 second laps will have significant pull but not enough to cause concern on a properly trimmed airplane.

Randy Cuberly

[Gary Dowler]

A friend who is a highly educated engineer and well known C/L flyer since the 50's has built a 75" Lystrander with a Enya 91 for power. Yeah, it's big. He calculated based on speed, weight, etc, that line pull at full throttle to be about 13 lbs.

Anyway, there are a myriad of factors that determine line pull. This was mentioned already. Speed, c/g, rudder offset, leadout position, plane weight, thrust offset, etc.   Just build it and fly it. If it's uncomfortable then sell it.

[Motorman]

But does extra pull effect your flying?


MM

[Steve Helmick]

It'll be good, you'll like it. It won't affect your flying if you keep your elbow bent and let your biceps take the pull instead of letting your arm be pulled straight (tendons taking the load). David isn't a large guy, but he looks to be very fit. I'm large and old, but not very fit.    I don't think you'll have a problem.    Steve

[Randy Cuberly]

But does extra pull effect your flying?


MM

It's difficult to say what "extra" pull really is.  Obviously, some people are stronger and in better physical condition than others.

Many years ago I built and flew a Trivial Pursuit that weighed 74 oz, it pulled a lot even when properly trimmed (which it was).  It flew very well and was easy to fly accurately even though it required a strong arm in the wind.

The only detriment that I noticed at the time was that I could only fly about 6 flights or so in a morning without getting tired and wanting to STOP!  I was younger then (about 12 years younger) and stronger and in better condition. 

Several years later I built and flew a 53 oz Geo XL and could fly 12 to 15 flights in a day without undue tiring.  So in my opinion it does make a difference but not really in one's ability to fly the airplane well!

The real key is having a well trimmed airplane that does what YOU want it to do and is reliable.  If you ever feel like you have to really "work" to make corrections during maneuvers, then the airplane is not "There".  This is much more important than how much the airplane weighs!

Randy Cuberly

[john e. holliday]

It is not only the pull, but you need to take into consideration your balance.   With my health I have balance issues, especially on a rough grass field.   It only bothers me a little if I don't get out within a week or so.   I have had several planes in the 60+ ounce range and it is work to fly them and stay in the circle.   I only put up one flight on the B-25 the other night as I'm still not used to it and it needed some alignment done to the surfaces.  Flew my little Chupim 20 one flight and amazing how well it flew and the pull it has lets you know its there for a small plane.  Of course on 52 X .015 lines felt good to me.