Dean_Dolph
09-18-2004, 09:57 AM
Brian, I'm posting this here because (drum roll and pats on the back!) being the nice and thoughtful guy I am I didn't want to hijack the thread that you posted in the General Discussion forum about keel flex. It is a good and valid question and you gave the reason for it by saying that you are thinking about a composite tall tail for your Bee.
I guess you know that Ralph's Bee design is very, very close to the ultralight weight limit so by doing this you will put your Bee in jeopardy of breaking out of the ultralight class. If you are not concerned about that then there is no problem.
People tend to think that composite construction is lighter than other forms when in fact it can be heavier. While the foam used is relatively light, by the time you add in the mounting hardware, the fibre and the resin it can get heavy in a hurry.
In my mind the appeal of composites is the that sexy compound curves can be made easier than with metal, the surface is smoother and it is easier to build a structure with less seams which all add up to less drag. But for most people that isn't a factor since a gyro is so draggy in the first place.
Personally, if I ever get around to working on the 1 1/2 Bee kits I have, I will stick pretty close to the Watson tail design but will think about modifying it where there is a little more vertical fin and rudder area and move the horz stab up so that it is a little more immersed in the prop wash. It has been explained, and is understandable, that a horz stab in the prop wash performs like a tall tail. Doug R. has already mentioned doing this which, for me, verified my thinking. But by doing this I will also be making things heavier so I'll have to think seriously before making any mods since I do want to stay ultralight if at all possible.
I guess you know that Ralph's Bee design is very, very close to the ultralight weight limit so by doing this you will put your Bee in jeopardy of breaking out of the ultralight class. If you are not concerned about that then there is no problem.
People tend to think that composite construction is lighter than other forms when in fact it can be heavier. While the foam used is relatively light, by the time you add in the mounting hardware, the fibre and the resin it can get heavy in a hurry.
In my mind the appeal of composites is the that sexy compound curves can be made easier than with metal, the surface is smoother and it is easier to build a structure with less seams which all add up to less drag. But for most people that isn't a factor since a gyro is so draggy in the first place.
Personally, if I ever get around to working on the 1 1/2 Bee kits I have, I will stick pretty close to the Watson tail design but will think about modifying it where there is a little more vertical fin and rudder area and move the horz stab up so that it is a little more immersed in the prop wash. It has been explained, and is understandable, that a horz stab in the prop wash performs like a tall tail. Doug R. has already mentioned doing this which, for me, verified my thinking. But by doing this I will also be making things heavier so I'll have to think seriously before making any mods since I do want to stay ultralight if at all possible.