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-   -   plane size? (https://www.rcuniverse.com/forum/questions-answers-154/10005274-plane-size.html)

rye 09-15-2010 08:32 PM

plane size?
 
hi i am flying the gaint scale rv-4 and this winter i like to build this plane https://www.balsausa.com/store/produ...?id_product=41 it has a bigger wing and is a high wing but a short body do they fly better or wroths then a plane with a longer body? thanks rye

abaser 09-15-2010 09:11 PM

RE: plane size?
 
Im just a relatively new guy here but from everything that Ive been told, and read, the longer the body, the better. Currently I only have a coulpe .40 size planes with short fuses and they are very twitchy in the air. My recently departed hog bipe had a much loger body and it flew great.

huck1199 09-15-2010 09:13 PM

RE: plane size?
 
Generally, planes with longer tail moments are easier to control.

rye 09-15-2010 09:17 PM

RE: plane size?
 
hi
ok this is a kit so can i extend the body i dont mind replaceing the hardward and i am going to make the rudder a pull -pull any way thanks rye

Charlie P. 09-15-2010 09:31 PM

RE: plane size?
 
If you extend the fuselage you should move the firewall/engine forward a bit as well. Otherwise you'll have to add nose weight.

The Citabria is a great flying model (and full-size aircraft). Personally, I woudn't second guess the designer. Toss some exponential in the radio and you'll have the best of both worlds.

Remember "easier to control" means "less maneuverable".

Gray Beard 09-15-2010 09:38 PM

RE: plane size?
 
1 Attachment(s)
Photos of two planes, one is a pattern plane and the other is an IMAC plane. Both planes will do everything you can think of plus some. The long moments on the pattern plane make it smoother and tracks better for more presision flying. The Extra 260 has much different moments and does everything the pattern plane will do but it does them quicker. That's the simple way to say it I guess. The PRO your looking at is one very outstanding stunt plane, very smooth and will do it all. I always tell people when they are building it's there plane and they can do anything they want with it. I know no one that has ever changed the moments on the PRO, why would they, it does everything the plane was designed to do and it does it very well. If you want a pattern plane maybe you should look at the Blue Jay web site for some of Joe Bridi's designs for some of the old school pattern planes instead of a stunt trainer. The prices are right and there is a good selection of designs. I just finished one of there Dirty Birdy kits last week, nice build.

da Rock 09-16-2010 09:17 AM

RE: plane size?
 
If the only thing that mattered was the length of the tail, every airplane, fullscale or mode, would have long tails. Maybe. Maybe not.

Problem is that length is not even the most important detail (pun intended).

Take the P40 Warhawk for example. Remember that most airplanes have both a horizontal and vertical tail. Length and area matter for both.

The Warhawk as it was designed, approved, and produced originally had a problem. It was unstable in yaw. They solved the problem two ways. First solution was to add area aft. That worked. There is a strong argument about length being the only solution. They started extending the fuselage in the middle of the P40F series run and didn't need the extra area. And they didn't move the horizontal tail back when they moved the rudder back.

Had the vertical tail had enough area, none of that would have happened. The Warhawk would have been just as smooth with a shorter tail.

Balance, weight, strength, durability and a few more things go along with aerodynamics when designers are juggling the numbers trying to fit the mission requirements. If you've ever used and studied the CG applications you can see how there are way more than one thing that matters. The Warhawk horizontal tail could have been moved aft too but if it hadn't been downsized could have upset the balance. But why change something that was working ok.

TomCrump 09-17-2010 07:10 AM

RE: plane size?
 


ORIGINAL: rye

hi
ok this is a kit so can i extend the body i dont mind replaceing the hardward and i am going to make the rudder a pull -pull any way thanks rye

This is a scale design. By extending the fuselage, you will be changing the scale looks. Is that what you want ?

This kit has been produced for years. It's a successful design. Why mess with it ?

Augie11 09-17-2010 07:55 AM

RE: plane size?
 


ORIGINAL: TomCrump



ORIGINAL: rye

hi
ok this is a kit so can i extend the body i dont mind replaceing the hardward and i am going to make the rudder a pull -pull any way thanks rye

This is a scale design. By extending the fuselage, you will be changing the scale looks. Is that what you want ?

This kit has been produced for years. It's a successful design. Why mess with it ?
Planes with 'short bodies' are called short coupled. It really depends on the ratio of lengths of all the parts. In general, they are somewhat more 'touchy' on the ground during takeoff. And consider that you'll be moving from a trike to a taildragger.

I'd leave the design alone-it's been successful for years. You need to learn to handle the aircraft as designed before you attempt modifications to compensate for the way it handles. Just my personal opinion.


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