Krill Spark Build questions

[rmarsden]

I am putting together a Krill SPark F3A airplane. This is designed explicitly for electric flight, so Ill be using a Neu 1515/3D or Neu F3A motor. Now for the questions:

1. Is it better to use a bellcrank like the MK bellcrank and locate the elevator servo forward near the wing spar or preferable to use two smaller servos mounted in the horizontal stabs? It seems that the bellcrank option is preferable for matching the elevator throws and for reducing weight in the tail.

2. What servos do you recommended for the ailerons, stabs, rudder? And why?

Thanks!

[jonigira]

preferable to use two smaller servos mounted in the horizontal stabs.
Servos s9650 Futaba digital

YouTube - Spark F3A - Jonathan Girabel - Krill...

regards-

[Temptation]

I have flown my pattern planes with just about every combination of elevator control out there. I am currently using two servos mounted in the stabs. I like this the best out of everything I have used in the past. If you use JR then use the DS3421sa servos. They are perfect for pattern elevators.

[joenella]

I have flown the Krill spark now for my 3 rd season, I have tried 3 different options and must say the one with I like best with less CG issues is the one where you use 1 std size servo with pull-pull, I mount my servo just behind the sudder servo.

[rmarsden]

	Quote: Originally Posted by joenella
	I have flown the Krill spark now for my 3 rd season, I have tried 3 different options and must say the one with I like best with less CG issues is the one where you use 1 std size servo with pull-pull, I mount my servo just behind the sudder servo.

Can you post a picture of your pull-pull setup or PM a picture to me? I would like to see this. Thank you!

[sideways]

Have you considered the D.E.P.S system from Central Hobbies?

	Quote: Originally Posted by rmarsden
	I am putting together a Krill SPark F3A airplane. This is designed explicitly for electric flight, so Ill be using a Neu 1515/3D or Neu F3A motor. Now for the questions: 1. Is it better to use a bellcrank like the MK bellcrank and locate the elevator servo forward near the wing spar or preferable to use two smaller servos mounted in the horizontal stabs? It seems that the bellcrank option is preferable for matching the elevator throws and for reducing weight in the tail. 2. What servos do you recommended for the ailerons, stabs, rudder? And why? Thanks!

[rmarsden]

	Quote: Originally Posted by sideways
	Have you considered the D.E.P.S system from Central Hobbies?

Definitely another good option.

The D.E.P.S. looks like it would accomplish the same elevator matching goals as the KM bellcrank but: require larger penetrations through the fuselage, be more work to install, and not save any weight compared to the bellcrank setup. It probably does move the CG slightly furter forward than the bellcrank.

[RV-8]

I am running two futaba 9650 servos in the stab, and futaba brushless servos for the rudder and ailerons. Even with the two servos in the stab my battery sits over the landing gear. The C/G posted on the web site is far too nose heavy and after my test flight I had too move the batterys back.

You will love the Spark one of the best pattern ships I have flown

[joenella]

	Quote: Originally Posted by rmarsden
	Can you post a picture of your pull-pull setup or PM a picture to me? I would like to see this. Thank you!

Here you go.


For power I use Mega ACn F3A motor with 22x12 prop, controller YGE 80HV which is THE best controller tried ever.

[rmarsden]

	Quote: Originally Posted by RV-8
	I am running two futaba 9650 servos in the stab, and futaba brushless servos for the rudder and ailerons. Even with the two servos in the stab my battery sits over the landing gear. The C/G posted on the web site is far too nose heavy and after my test flight I had too move the batterys back. You will love the Spark one of the best pattern ships I have flown

Thanks RV-8. So, where is your CG now, relative to the wing tube?

This is my first pattern plane. I have 25% and 35% IMAC planes and am in the process of building a 40% ZN-Line Extra in addition to a 'few' smaller planes.

My new Spark does not have a counter balance on the rudder as shown in most pictures of the Spark. Does your have counter-balance on the rudder?

[rmarsden]

	Quote: Originally Posted by joenella
	Here you go. For power I use Mega ACn F3A motor with 22x12 prop, controller YGE 80HV which is THE best controller tried ever.

Joenella, thanks for the pics! I'll look into the Mega ACn as an alternative - always fun to try something new. I already have a couple of spare Castle Creations HV-85 ESCs so I'll use one of those.

[1bwana1]

Randy,
That thing is not done yet??? If you want to see a live D.E.P.S system, my Passport is set up this way.

[rmarsden]

	Quote: Originally Posted by 1bwana1
	Randy, That thing is not done yet??? If you want to see a live D.E.P.S system, my Passport is set up this way.

Steve,

The research is as much fun as the build. Plus I need to work on the ZN too.

[joenella]

	Quote: Originally Posted by rmarsden
	Thanks RV-8. So, where is your CG now, relative to the wing tube? This is my first pattern plane. I have 25% and 35% IMAC planes and am in the process of building a 40% ZN-Line Extra in addition to a 'few' smaller planes. My new Spark does not have a counter balance on the rudder as shown in most pictures of the Spark. Does your have counter-balance on the rudder?

Spark version 2009 DOES not have the counter balance on the rudder, so you got the newest version

I fly both version 2008 and 2009 and the 2009 flies a few percent better.

My CG i just 15 mm ahead og wingtube center.

[RV-8]

	Quote: Originally Posted by joenella
	Spark version 2009 DOES not have the counter balance on the rudder, so you got the newest version I fly both version 2008 and 2009 and the 2009 flies a few percent better. My CG i just 15 mm ahead og wingtube center.

Hi Guys

Sorry I have not posted in a while but I was called out on a flight and have been away for 6 days. The plans on the net show the C/G 30 mm forward of the wing tube. When I first built my Spark I had the batterys all the way forward just behind the motor and the lipo for the rx also right at the front, even then I could not get the plane to ballance, ie I was still tail heavy. I thought I would fly it and then take the two elevator servos out of the tail and replace them with a single servo in the fuz. The C/G just did not look right it was about 10 to 15% MAC most pattern ships are 25 to 30% MAC. Well my first test flight confirmed my fear, the plane was WAY nose heavy. On an inverted 45' up line the plane would immediatly pull to the canopy. I then on subsequent flights just added more and more lead on the tail until I got a C/G that I was happy with. It it quite a bit further aft than the plans. I then had to cut out my bat tray and relocate the motor batts to more or less over the landing gear. I aslo moved the receiver bat rearwards and placed it next to the rx.

At the moment if I leave the wings and canopy OFF the fuselage and every thing else on (stabs, batts, prop, spinner, ie ready to go) and pick it up by the wing tube the fuselage hangs slightly tail down. This will be a good place for you guys to start and you can fine tune it from there. Next time i go practise I will balance it with the wings on and let you know.

I have included some photos for you guys of my set up. hope it helps