PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

4.3g for the Rx with combined servos and brushed esc
6.1g for the motor and gearbox
1.1g for the prop
4.2g for the lipo
Total 15.7g

Thats not so bad Martyn

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

TAKE TWO...........

Three views are scaled and positioned in a matrix, alligning major dimensions in all three views, using a 45 degree line to reflect the dimensions. All old stuff, that i am sure you know.....

This wont be so bad as I am faster with the tools, and I have it worked out in my head what I am doing..... makes you really appreciate and respect the designers!

Cheers
Danny

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Please Log in or Create an account to join the conversation.

Please Log in or Create an account to join the conversation.

Replied by Quorneng on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

Third angle orthographic projection as used in the States (Europe tend to use first angle) but then it is an American plane.
Very nice but it is almost cheating using CAD!

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

Cheating! :woohoo: I need all the help I can get I tell you

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

Okay we have a new wing, this time I have added the riblets. Interesting that the rib spacing is totally different to the flapped variant.

Better see about the ribs and riblets, you will notice there is a step in this new wing which means the spars have to change course, deep joy.......

still it would be no fun if it was easy....

Cheers
Danny

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Replied by Quorneng on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

Sceptic
Is there really a 'step' in the front spar on the full size?
I would be surprised if there was.
This picture of an uncovered wing suggests it is only the leading edge covering that is cut back outboard of the wing strut location. The spar continues to the tip - but I could be wrong.

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

I have some factory drawings I will take a look. As you say the sheeting steps and the riblets can be seen to be the same length. if the spar is continuous then it is a long way forward in the structure. I took my spars from the cabin ceiling beams, expecting to comtinue them right out to the tips.

I have finished the ribs (apart from the tip rib)

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

You are quite right, the spar continues Well spotted.

Cheers
Danny

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

I will leave all the maths to those that do them without a blinding headache. I need a button in cad that will give me the wing area I can do the straight bits the tips I struggle with, I believe Andy that the area includes the tailplane?? does it also include the fuselage underside in the calculations for wing loading?

Re-worked the wing layout following from the spar revelation this morning from Thanks for your help guys

Right need to do some real work, maybe squeese more in later....

Cheers
Danny

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

A quick Google and there is a way to measure the area within Turbocad, should have guessed really :whistle:

So the wing alone is 120.86 sq ins

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.

Please Log in or Create an account to join the conversation.

Replied by Septic on topic PA-18 Super Cub for the BMFA R/C Scale Indoor Nats

Thanks Andy, according to my calcs the total area of the wings, plus centre section and tailplane is 151.29 sq ins
this is 97606.26mm² which is 9.7606 dm²

so times 9.7606 by 15 to give max legal weight............. drum roll........

146.409g

My head hurts time for a lie down.....

---

tap - tap.......rivet

Please Log in or Create an account to join the conversation.