RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Any thoughts on the performance of the RASA 20.5, and can you speak to the quality of the Spark kit? What would you say are the highlights/lowlights so far?


By the way what's a Kookaburra, and doesn't it bother you that you live in a place where some of the deadliest critters roam [X(] I don't think I could sleep at night. I guess it's all in what you're used to, heh? ;)


Joe

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Yes, it's what you're used to for sure.

Last week I stepped off the back veranda and a snake was slithering up the side of the house about 2 feet from me. I didn't have shoes on either! The snake stopped in its tracks, looked at me and then disappeared under the house.[&:]

A kookaburra is a native bird. They have a big beak. http://www.kidcyber.com.au/topics/kookaburra.htm

The RASA 20.5 x 14 was ok but to be honest I didn't notice a whole lot of difference between it and the RASA 20 x 13. I think more time is needed with it to make a fair assessment. Perhaps I was expecting too much?

The Spark is a nice model. The quality is pretty good although the finish is not to an Oxai standard. I think the instructions are a little weak. They don't cut the holes for the control horns so you have to work out their location yourself. It wouldn't be hard for Krill to cut the holes in the correct position. The flight characteristics are pretty good though. The weight is ok but if I was using the AXI 5330/F3A i'd be very close to the 5050 gram limit. Still under though.

I must say that my Spark is the 2008 version so the new one may be of better finish/quality not that the 2008 version is bad.

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Hi guys, moving slowly with my Spark, indoor season keep distracting me from finishing this nice plane...;) So one question about colling holes in back of fuselage. On gas ore glow engines colling is important for long life of motor, in electric we have ESC motor and battery and all of them require some colling. Because of spark shape its quite hard to make allot of intake holes in front, so i suspect exit holes are also not that big. Let me know what size are ok, and do you get problems with overheating something in hot summer days.

Thank you in advance,
Donatas

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Donatas,

I don't have a Spark, but I can help you with your question. You need to have more area for the air to exit than you have for air to enter. If you have more entry area, then the air will stay locked up in the fuselage and will stay too warm. You need twice (at least) the cooling exit as you do the entry to suck the air out.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Don,

What motor are you going to use?

The type of motor will determine what type of cooling holes you need to cut.

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Ryan thanks for tips, i had same understanding, this just show that i was on right way.

Jason i will use outrunner AXI 5325, any pictures how this should be done.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Sounds like you'll be using the same motor as me then...:D

Krill make a firewall for the AXI and this is what I used. It will need some trimming to get fitted correctly.

I found that with the standard cut-outs as per the pictures on the CD, the motor ran too hot here in Australia. I have since made four holes between the firewall and nose ring that are 6mm wide x 20mm long. They are positioned top, bottom, left and right hand side. This small modification makes a huge difference as it allows air to flow through the firewall and then through the motor.

I'll try to get some pictures for you tomorrow.

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Here are some pictures

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

As promised, a couple of pictures showing my cooling holes. The small ones aft the spinner backplate made the biggest difference.

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

This picture shows the outlet holes in the sides. I cut these before doing the ones aft of the spinner and they made no difference whatsoever.

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Thank you guys for pictures and advices, i will get back on Spark, in end of April when i get back from ETOC and Dortmund intermodelbau;)

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

very nice pics...good job guys !!!!.. we wish to look any videos, too !!!!!..

cheer, from Spain

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

G'day Andres,

Unfortunately I don't have any videos of the Spark. We all have yours to look at instead ;).

Would you happen to have the component weights of your 2009 Spark i.e. wings, stabs, fuse, canopy etc?

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

G’day Joe,

I have been using the RASA 20 x 13 for sometime now on the Spark. This has given me a chance to get used to it’s performance. Last Sunday I put the RASA 20.5 x 14 back on. Wow, what a difference! While the bigger prop uses about 200-300 mAh more per flight, the performance is far superior. When I initially tried the 20.5 x 14 I could not tell much difference. I suspect it’s like when you put new tires on your car, you get used to a certain performance and when the new tires go on you wonder how you drove with the old ones… Hope that make some sense.

Some good news too.. I got my last promotion point the weekend before last. Now I’m in Expert class. It’s been a long time coming….

http://www.nswpattern.org.au/Home.html The Spark is now front page news! :D

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Spark update...

During the winter I was talking with Mark Atwood and Dave Snow about the Sparks, we all agreed it was a great flying airplane but had a bit of coupling we wanted to get rid of in knife edge, mainly pitch to the belly. I have tried to move the CG all around to correct the problem but with it to far forward I lost the feel of the airplane. I talked Dave into making a set of Anhedral stabs for the plane. I didn't want it to be to noticable, but I wanted it to be effective. We came up with 4 degrees of anhedral and it took my mixing from 7 percent in knife edge down to 2 percent. I can live with that with out a problem. Plus when I put the wood wings and stabs on there my spark with a 10s5000 mah pack now weighs right at 10 pounds.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Im curious if you tried the new stabs with the stock wing....before putting the new wings on...,and if you had the same result..

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Yes the plane has been flown with the stock wings and anhedral stabs, It was the same result. The wood wings are the same as stock wings just a bit lighter.

Andrew

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

G'day Andrew,

Did you try more +Ve incidence on the wings with the forward CG?

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

I did try moving the wing incidence and found I didnt like the look of the airplane where it flew at. I got a few PM's asking if I thought this was necessary for the airplane. It is far from it, I just wanted to take an awesome airplane and make it even better. I flew this model completely stock at the Nationals and worlds and am very happy with it. As you know how pattern guys are we cant leave good enough alone and thats what these mods are.

Andrew

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Good point Andrew. The IMAC guys at our field and they are growing are always telling me that pattern guys change designs too often. It's just that were always looking for something a touch better. Something that will improve us and give us that little advantage. It's one of the things that I like about pattern. It's a little like Formula One racing .
Mike

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Andrew, Since you have set up several SPARKS...could you give me an idea of what you are doing for mounting the C50 hacker?...Are you using a dampened mount like the Budd mount which is similar to the one Krill makes?, whats your opinion of theses? are you doing any extra reinforcement in the nose area?..do you like to use the hacker fiberglass ring?
Thanks, George

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

G'day George,

Take a look at post #53 on this thread. Looks like Andrew uses a Hyde mount to me.

Cheers
Jason.

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Jason..
The rear of the mount is clearly visible....I was curious what is up front..
What did you use?
Geo

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Geo,

On my new Sparks they have a rubber isolated mount in the front. It is similar to a buddy mount except that it only uses 2 points of attachment to the nose of the airplane instead of 4. Basically its a piece of carbon fiber that has the hole cut for the hacker to fit through. Then it has a tab off to the side of each. Drill a hole in the tab and put a rubber grommet with an aluminum spacer in there so it can only squish so far. That is the front mounting, the back is just a piece of carbon as well that uses fuel tubing around the motor to support the back of the motor.

Andrew

RE: Spark F3A, from Krill Models - SPAIN TEAM
 

Andrew,How is the Q-80 mounting coming along?