New Flight: Pitts -Skelton Aerobatic model (page 9)

Thanks Brad for your time! Here are the screenshots.

Kim wrote:Looking Great, Mauricio !!!!!!!!!!!!

Kim, it is an honor for me that you are here too! ... Sincerely!

What is the all up weight and total square inches of the combined wings?

1/2A Nut wrote:What is the all up weight and total square inches of the combined wings?

Comparison between PITTS and BI-HAWK

PITTS
Wingspan: 29.8 inches (top wing)
Wingspan: 21.02 inches (bottom wing)
Fuselage length: 19.88 inches (including rudder)
Engine: Norvel .061 r / c
Radio: 4 channels (engine, spoilers, rudder, depth)
Weight: 630 grs = 22.2226 zz

BI-HAWK
Wingspan: 30.11 inches (top wing)
Wingspan: 25.98 inches (bottom wing)
Fuselage length: 21.65 inches (including rudder)
Engine: Cox Medallion .049 r / c
Radio: 4 channels (engine, spoilers (lower wing only), rudder, depth)
Weight: 554 grs = 19.54 oz


Wing load PITTS S-1:

Bi-Hawk
A1 = 765 mm x 120 mm = 91800 mm2
A2 = 660 mm x 120mm = 79200 mm2
A1 + A2 = AT = 91800 mm2 + 79200 mm2 = 171000 mm2
171000 mm2 to in2 = 265,05053 in2
Alar Load = Weight / Total Area = 554 grs / 265,050 = 2,090 grs / in2

Thank you Mauricio

1/2A Nut wrote:Thank you Mauricio  

 

You have taught me a lot of friend, it is a pleasure to share information here!
What do you think? .... do you like the wing loading of the Pitts ??

Yes will be faster with more acro ability / will act like a Pitts.
Needs a .074 to hover on the prop but the .061 should make
it dance well.

Thanks Brad !, I think the Norvel .061 r / c will take it very well, I think it is a more similar relationship to the real flight, but anyway everything is to see what happens at the time of the flight.
I will be measuring the pulling force of the motor shortly.
Due to the restrictions in my city (Covid 19), I must wait for the appropriate moment to go flying ...

APC 6x4 Sport Propeller is a very good 1/2A prop for thrust and reasonable pitch speed:


The Norvel AME .061 should make around 17.5 oz thrust/ 65 mph pitch speed



AP .061 RC / APC 6x4 gas sport prop / 16,795 rpm / 17oz thrust
Static: 64 mph pitch speed / .176 hp - 131.3w
25% nitro / 20% castor oil.

Thanks friend for this valuable contribution, I do not have the possibility to get the APC 6x4, here everything seems to get a little more complicated .
Here are my tests with my available propellers:

Lovely data

 

Umm... Am I reading this right?

The APC 6x3 ran 17790 RPM, and has a pitch speed of 40
The MA 6x3 ran 15930 RPM, yet outran the APC with a pitch speed of 60.3?

Fixed thank you.

Very Impressive my Friend !!

1/2A Nut wrote:APC 6x4 Sport Propeller is a very good 1/2A prop for thrust and reasonable pitch speed:

Just curious, but that looks like an "E" (electric) prop. Is it? Is the prop strong enough to withstand the impulses of a nitro glow motor?

It is a glow sport prop perfect for 1/2A

I have ran it with a AP .061 / Norvel .074 /  TT GP .07 and SH .07  

https://www.apcprop.com/product/6x4/

- on the site scroll down for related props.



Note during testing the most static load to date put on APC 6x4 sport
Norvel .074 Kamtechnik Turbo Plug  
19,864 rpm / 23.3oz thrust / .292hp - 214w / 75.2 mph pitch speed
+ 1,211 rpm
Vs
Norvel's upgraded Turbo Plug adapter / APC 6x4
18,653 rpm / 21oz thrust / .242hp - 181w / 71 mph

And yes friends! The great moment has arrived!
After several attempts to take off, I had to make the following corrections:
1) propeller change, needed more traction.
2) minimization of controls on all controls.
3) Incidence of the upper wing 1 degree, lower wing 0 degrees, stabilizer 0 degrees.
4) Let it run for many meters, the grass track slows it down a lot, so there is no need to rush, just let it go and touch the elevator gently.
5) The Norvel .061 motor takes it very well, although it fits perfectly, maybe a .074 or more motor, you could have fun doing crazy things.
Conclusion: I AM HAPPY! nothing more to add!
To my brothers, especially José Emilio, Lucio and all of you my love and gratitude, for being there, for being part of this, God bless you!

I E-kiA!! Great flight !! Very Happy for you to go fly with the new bird and come home all in one piece !! Love the sound with the full cowling / engine Very happy for you Friend!! Large Hug!! and enjoyed the build thread !! What prop did you decide on ?

Congratulations Mauricio very nice flight and model. I am glad you could finally do the maiden flight despite Covid!

So happy to see the plane has made it through the trim flights MauricioO!

Looks like the mighty APC 6x3 by design proved to be a fast rev / top thrust prop.
Low drag prop tips to get the bird up and away.

What size wheels are those?

Can you go up a bit in diameter to reduce take off distance and
allow other props to get it in the air.

Modified APC 7x4.1SF prop to 6.75x4.1N / 14,600 rpm 567g / 20oz thrust / 57 mph pitch speed.  


         

FANTASTIC !!! Really enjoyed the build and video of the flights .  

                            Mike1494

THANKS GUYS!!!        
Well, I am experimenting with new propellers, this time a Master 7 x 4 G3, it seems to go very well in static, the engine reaches 11500 rpm with a force of 410 grams. It will be a matter of testing in flight.
I have also changed the anchors of the upper wing, the material used before is very hard, but brittle at the same time, so I made all that new with MIDWEST wood that will certainly last forever.
I will continue to share the progress.
Brad, what do you think about cutting the propeller? APC I don't have in STOCK





Another good news is that Mary from Outerzone (  https://outerzone.co.uk )has updated the page with the images and data of my Pitts, so maybe more friends want to make one! : https://outerzone.co.uk/plan_details.asp?ID=6495
I'll keep up with the news!