Build: Kimball-Somenzini Python 100

[Reza]

I am a little disappointed in the amount of deflection of ailerons! I doubt I can keep up with the roll rate of 700 degree per second at full deflection

[Reza]

Now question for all of you:

When I wrote the Yak-54 manual I did not use Dubro nuts and washers because especially on ailerons they may not sit flush, most modelers over tighten them and crush the aileron, so I epoxied the bolt or threaded rod and it worked great. Which way would you rather do or see the manual done on that matter? Cut the head of the bolt with dremel and epoxy or use complete Dubro hardware. I will show you a method that you can use Dubro without crushing the balsa. I also know about using CA and making balsa harder but generally which way would you prefer doing this?

[MikeC3D]

epoxy bolt in wing , cut bolt head off......nice looking bird, I love my 102" yak.

[Eury]

Can you tell us what the dimensions are on it? I sent an email to the contact on QQaircraft, and got the ridiculous answer that they didn't know the wingspan or length until the production planes came in.

[Reza]

Nick,

Wing Span 85"
Length including 4.5 P-51 spinner 90"
Wing area 2,380 Square-Inch

[Eury]

Thank you, sir.

[JeremyHolt]

	Quote: Originally Posted by Reza
	Now question for all of you: When I wrote the Yak-54 manual I did not use Dubro nuts and washers because especially on ailerons they may not sit flush, most modelers over tighten them and crush the aileron, so I epoxied the bolt or threaded rod and it worked great. Which way would you rather do or see the manual done on that matter? Cut the head of the bolt with dremel and epoxy or use complete Dubro hardware. I will show you a method that you can use Dubro without crushing the balsa. I also know about using CA and making balsa harder but generally which way would you prefer doing this?

Epoxy I believe is the strongest and cleaner install of the two. I guess you could leave it up to the builder with both options...

[Reza]

I will show both method in the manual but would like to get a taste of what most of modelers would prefer. I am doing epoxy on my own plane. Think about all the weight you can save by eliminating those aluminum nuts

One thing that is a little different on this plane than the Yak is the control horn holes are already burnt so either you need to cover it with a small piece of ultracote from top or just leave it as the bolt is going to be flush anyway.

	Quote: Originally Posted by JeremyHolt
	Epoxy I believe is the strongest and cleaner install of the two. I guess you could leave it up to the builder with both options...

[Reza]

You are very welcome!

	Quote: Originally Posted by Eury
	Thank you, sir.

[airriley]

Couple of weeks ago at an IMAC contest a guy had one of those aileron bolts break on him. He went with the cut head off and epoxy bolt in option. Had a heck of a time getting that bolt out. For me personally I would still go with the weight savings.

[Reza]

When you go with the bolt without the nut, your moment arm increases, I will show this in the next pics. Weight saving is 1.2 oz minus whatever the weight of the glue is, I would say 1 OZ savings total. I was really kidding about the weight saving but 1 oz is a Digi-Switch for your ignition so it does count!

I will look up the material property and do a calculation tomorrow but to me it takes a lot to break it in bending unless his bolt was very long and I assume it was a 40% somehow there was an excessive force applied to the point control horn and bolt are connected. Basically it is a cantilever beam and bending is Maximum at the root where it is glued to the aileron.

Getting the bolt out is very easy if you have a soldering iron that heats up to 800F or so. I had to pull mine out on my Yak due to scraping the aileron in a low rolling harrier circle and I managed to bend one of these bolt, didn't break but got bent! Anyway, you heat it up to 800F for 30 seconds or so and twist the bolt, it comes right out! In fact you smell epoxy being burnt!

The nut set up is certainly a stronger set up and give an extra support to the bolt but I still don't think it is really necessary. I leave it up to you guys.

If you look at the attached pictures, you will see that your moment arm is 0.5 shorter so if let's say we apply a force of 20lbs at the tip of the bolt, moment induced with the nut is 10 lb-in and without 20 lb-in if we consider the length extruding off of the aileron to be 1".

Thanks for sharing this with us,
Reza

	Quote: Originally Posted by airriley
	Couple of weeks ago at an IMAC contest a guy had one of those aileron bolts break on him. He went with the cut head off and epoxy bolt in option. Had a heck of a time getting that bolt out. For me personally I would still go with the weight savings.

[Reza]

And here is the weight saving pics LOL