Thrust needed for a parkflyer

[andyg]

The plane specs: span = 40in. length = 28in.
weight = 30 oz. wingloading = 15 oz/sq ft. chord = 7in. aspect ratio = 5.5
airfoil = Clark Y

This is a high wing trainer so it doesn't need to be fast just be able to climb nicely.

I plan to use a Lipo. The actual plane doesn't weigh 30 oz. it is just an estimate for when all of the UAV equipment is in it.

The equipment for the initial rc flying is around 4 oz. including a motor estimated at .88 oz. I am making it out of blucor foam so it should not be to heavy. I'm guessing it would really turn out to be around 15-20oz. with radio gear. Which would bring the wing loading to around 7-10oz./sq ft. I just want to have a little extra power in case I want to put a few ounces of electronics on it.

Do you think I need more wing area? Do you think 15 oz. /sq ft. is a lot. What do your foam parkflyers usually come out to? Thanks for your help

P.S. I have a 1300 mah 2s Lipo and a 1100 mah 3s lipo but if these end up I think they are rated at 8c and 10c respectively. But if these won't work I'm willing to buy a new one for my new plane.

Does anyone have a suggestion about the amount of thrust I'll need to get this plane flying? Any help would be greatly appreciated. THANKS

Andy Goessling
andy@riddlehill.net

[Sparky Paul]

15 oz/sq.ft. IS a lot for a parkflier.
These typically run to half that or less.
Your thrust is dependent on the motor, prop, gearbox and battery, not any one of these alone.
You might look thru catalogs to see what equivalent sized planes use for power.

[andyg]

I'm going to build a Diy brushless kit so I just need to know the thrust needed. Thanks for the posts.

[vintage1]

You will need an efficint 100W or so to fly that plane.

30oz at 40" span unless its a very low aspect ratio will be quite a fast plane too..so you will need pitch speed on it.

Thriust is not so much an issue at all. Not stastic thrust. Youu want a pitch speed that will give you at least 6-7oz thrust at 30mph I reckon.

[adam_one]

The plane specs: span = 40in. length = 28in.
weight = 30 oz. wingloading = 15 oz/sq ft. chord = 7in. aspect ratio = 5.5
airfoil = Clark Y
Does anyone have a suggestion about the amount of thrust I'll need to get this plane flying? Any help would be greatly appreciated. THANKSYour parkflyer has a cubic wingloading of 10.2 oz/cubic ft., which is above the average 4 to 7 oz/cu. ft. for parkflyers.
As a rule of thumb the stall speed in mph is approximately equal to four times the square root of the wingloading in ounces per square foot.
So, the calculation resulted in a stall speed of 16 mph.
Unless it's a glider, the static pitch speed should be above 2 times the stall speed.
The thrust should be at least about 1/3 of the planes' weight in order to get reasonable climb and acceleration ability after aborted landings.