General Motocalc Questions...

[Aregorn1]

I am rather new to RC flying and I am trying to figure out a few things about the Motocalc program. I think I have an idea about how to read the results that the program generates, I will know for sure later once I start using it for actual models instead of just using data from store plains. But my main question is about a real basic issue. "Specifying the Level of Performance" I understand what the program wants but I am not sure what to select they describe what each covers but it is not in a form I really understand. For example what would I select if I have a foamie that I am going to fly normally, like just flying around in circles and fig 8s, with maybe a few loops, rolls, and spins, and maybe try a knife edge or two.

Any help would be great. Here is what the program lists as choices. If anyone would like to maybe expand on these descriptions it would be great.

Sedate − low power and a very low wing loading.
Trainer − moderate power and a low wing loading.
Sport − moderately high power, and a moderate wing loading.
Pylon − moderately high power, high wing loading, high pitch speed.
Aerobatic − high power, moderately high wing loading.
3D Aerobatic − very high power, very low wing loading, very high static thrust, low pitch speed.
Sailplane − moderately high power, very low wing loading, low pitch speed.
Hotliner − very high power, moderately high wing loading, high static thrust.

Thanks for the Help.
Michael

 

[corsair_pilot]

Hi Michael,
having a look at the options, I would be looking at either trainer or sport.
I consider myself relatively new, and I currently fly what they call a trainer, and it is a foamy. I am able to do what you've said you want to do with it.

 

[Aregorn1]

Almost forgot one other item I am having a hard time figuring out. using one of the KF-airfoils what would be the right selections to make in airfoil type and thickness, I wonder because my understanding of the KF-airfoils is that while the shape itself is flat, the airflow over the wing moves like there was an actual airfoil due to what I think of in my head as phantom surfaces. (I think its something to do with ahhh a vortex or something like that. LOL yes you can see how technical I am.)
Thanks for the help.
Michael

 

[corsair_pilot]

Ah ok... airfoils is going to be someone elses domain at the moment.
What are the options that you have to choose from with the airfoil shapes?

 

[Aregorn1]

HA HA that is the big question. from what I have seen in the list of actual airfoils that you can use I wouldn't even try to put that up here. WAY to big a list. but using the moto wizard there are 6 main choices. more like categories really to choose from with 4 levels of thickness on the next page. and there is also the option to enter the wing specs. Now I can measure the wing dimensions and get a result but like I say the KF type airfoils rely on that vortex effect from the wind passing over the surfaces to "I guess you could say" change the way the wind sees the wing. hence the problem. from what I understand there are still different studies being done on the KF type foil. I keep looking for someone to say ( a KF2 type foil that has a chord of XXX preforms like a NACA 6-8-15) and NO I have no idea what that is i just picked it from the list of airfoils. LOL I know that in the long run the differences are tiny in many cases, specially with the way I fly. (5 min flight, 10 min. repair. another 12 min of light then more repairs. LMBO But I like to have an idea that I can expand on later.
under-cambered,
flat bottomed,
semi−symmetrical,
symmetrical.
Flat Plate
Curved Plate

Thanks
Mike

 

[Lee]

Looking at the various Kfm foils.
I would say the Kfm1 is an under camber.
Kfm2 & 3 are flat bottom.
Kfm4 is a symmetrical.
Thats just my thoughts.

 

[corsair_pilot]

For the purpose of what you're wanting to do, I'd be looking at more of a flat bottomed wing section.
I'd be looking at using something like the clark-y profile

- - - Updated - - -

Here is a bit of good reading, and gives a bit of explanation in aerofoil suggestions
http://airfieldmodels.com/information_source/math_and_science_of_model_aircraft/rc_aircraft_design/plotting_airfoils/about_airfoils.htm

 

[Aregorn1]

Thank you Lee, that helps a-lot. it covers many of the airfoils that I am likely to use and points me toward the similar traditional airfoils, Motocalc will hopefully take away or should I say help me understand the electronics involved. After all a foamy without a motor is just a glider, (no offense to the glider pilots out there). Like I said I am rather new to RC and since almost all of my birds are built from plane old Dollar Tree foam. I love the hobby but a-lot of it is rather expensive. So I thought about it and came to the decision that in the long run I would get more enjoyment for my money if I bought mostly parts, motors, servos, etc.. than planes. Plus I really like the build and modify of scratch built. Then I hit the not so fun side, (electronics) LOL but you have to take the good with the bad.

Thanks Jonathan, you narrowed the field more. Would you say that the Clark-Y is close to a KFm 2, that is what it looks like to me? also thanks for the link, I only leafed through it so far but it looks good to me.

Thanks all
Michael

 

[corsair_pilot]

Clarke-y is a more traditional shape, and has a more "typical" shape about it.
I probably should ask a few other questions at this point.
Are you wanting to build you're own plane?
You aren't purchasing a kit?
If you're building you're own wings I would proably run with the KF foils, simply for ease of creation.
I'm building a balsa one and am using the clarke-y shape rather than the KF foils

 

[Aregorn1]

Right now all of the planes that I am working on are all made from Foam Board since that is the cheapest material to work with. I have two other birds that are store bought, a Cessna 182 from RedCat and a Dynam HawkSky. That is more than enough for me right now. I bought like 7 or 8 motor sets and maybe 10 each of 4 different servos mostly cheep ones that were sold in bulk. and I think 2 each 6,6,and 8 ch receivers then some odds and ends tools. Just about all I need to build them and keep me busy for a while. That is the reason that I am using the KFm airfoils they are the easiest to work with.

 

[corsair_pilot]

Certainly on the foam board planes, kfm seems very hard to go past, and that's what I would run with!
I would look at the other types if you're doing something with balsa.
the store bought ones are going to use some sort of clark type wing pattern.
Sounds like you're on top of it though!!
Can't wait to see pics and hear about the flights