slowstang88

After a couple years of trainers, then a sturdy birdy that I put ailerons on (and built a new set of wings for twice.. lol..) I decided to scratch build an EP park slowflyer. Its just 3 channel (rudder, elevator, throttle) until I can assure it's gonna be light enuf to fly first. Well the dimensions are L-20" span- 27" cord- 4" with hitec hs55 servos, gutted old 6 channel Futaba reciever, C-10 ESC, Electrifly GRU with 370 motor and 10x4.5 prop. The wings are hot wire cut from high density white styro with about 15* dihedral. Whats a good weight to aim for? I am trying to keep it as light as possible. I will post some pics of this flying POS in a while lol..

slowstang88

As promised, heres the crappy pics.

slowstang88

Nothing at all? Not even a "Your plane sucks and won't fly so you might as well crush it"?

slowstang88

Ok, nevermind then..

slowstang88

This website has gone straight down the crapper, and it parallels society. People arent building for themselves anymore, they wait for a company to make what they want. Not even 5 years ago this site was completely different, a lot of people building what they wanted and taking pride in it and the pros could tell you if your build was done right or not, but not anymore...

Iron Bottom

Here's the best info I could dig up, slowstang. The info was taken from an old "Design and build your own r/c aircraft" authored by Kenneth L. Smith. I have built several with the info from this publication and they all flew well.

Wing area 140 - 250 sq in. is in the .049 engine range.

There is no info for a wing in the 100 sg in. range, but suggests a weight of 20 oz. for a wing of 250 sq in.. Wing loading on this 250 sq in. wing carrying a weight of 20 oz. is 11.5 0z/sq ft. for a high wing rainer. A200 sq/in wing carrying 20 oz. will have a wing loading of 14 oz sq/ft, this figure is for a shoulder wing sport.

6-8 degrees total dihedral for a high wing 3 channel trainer is recommended.

I am just guessing here, but 8 oz. all up weight should be good.

Your dimensions look good, but I can't really be sure from the pictures. Good luck and remember: the first one is only a stepping stone to a really great flying model.

slowstang88

Thank you for your reply! I'm gonna do some glide testing after its all balanced out and decide if I need to make a new wing with more span and chord. The more I look at it, the more I think the wing loading will be too high. I also have no way of weighing this thing accurately (to the ounce/gram) and theres a lot I could have done to make it lighter but what I got is what I got! Live and learn from the experienced guys I guess!

Iron Bottom

I forget to mention something, Slowstang. Google RCM Plans. Go to requested articles. The Chuck Cunningham and Ken Williard aryicles will be a big help. Print those articles. A lot of older and valuable info has been taken off the web.

So, how did it fly?

guitardude

Not bad "slowstang88", if you'd like to build a kit next time you might want to look at the Herr Engineering Star Lite, Its supose to be a three channel, throttle, aelirons and rudder but I decide I couldn't live with out aelirons so I modified the wings.

Here's a link to my thread www.rcuniverse.com/forum/m_11179008/tm.htm

If you get bored, let me know what you think. Give me a shout if you have any questions.

siberianhusky

The articles on rcm really take me back, I actually remember reading some of those articles in print back in the day, thanks for the trip down memory lane!