computermonkey

My Feedback: (90)

Cool let us know how the engine combo works out.

[email protected]

My Feedback: (2)

just checking back after a few years. I still have my KK and it is my hangar Queen! It fly's straight and true, I just want to keep it beautiful.
But I am curious as to the one that Experimental Aviator was building. Anyone know what has become of this?
If anyone is interested I have been building a 1/4 scale Globe Swift and just finished. Not flown yet. Here is the link http://www.rcgroups.com/forums/showt...561963&page=45

[email protected]

My Feedback: (2)

Started yet another KK build just the other day on RCgroups is the thread.
https://www.rcgroups.com/forums/show...SIG-King-Kobra

Twin_Flyer

My Feedback: (4)

Where are you guys balancing your KK?

i got one from a club member that moved across the country and didn't want to ship it and his one compliant was that it was hard to land (didn't slow down).

After going through the pumped OS 61 SF and replacing the rings in the carb so it would idle, the one flight i have on it showed exactly that.

According to Sig, the CG range is 5" to 5 5/16". As it is now, mine is definitely on the nose heavy side with the battery and RX as far back as i can get them so looks like I will have to add dead weight to the tail.

For my first flight i had an APC 12 x 6 prop but will try an APC 12 x 8 (had read on another forum that this engine liked big props for breaking, 12 x8 or a 12 x 10) next, besides adding some tail weight.

Thanks

[email protected]

My Feedback: (2)

That balance point sounds right. Slowing down for a landing should not be a big deal unless you have no experience with this type of aircraft before. It's not a really hard aircraft to fly. For the prop, I think for that OS a 11 X 7 is ideal. Even with a tuned pipe. You need to be cranking around 13K to get the power from that motor.

coleboom

I have to fes up... I just got done building mine.. My intent was to build it to fly fast ad be sturdy... I covered the entire thing with 3/4 oz glass then painted with Latex and then clear POLY

I enlarged the bottoms of the landing gear openings and pored epoxy in and pushed the gear into thatll

Looks good (there are brush lines.

Long short with the 75ax and heady MG servos... All up weight is 9.5 lbs

It is of course winter here so I have not Maidened and likely won't till may or so...

Who has an opinion as to if this is Just too heavy... Too late to fix it but just curious... Win cubed puts it at 14 range so... heavy scale catagory

opinions wanted...

Hydro Junkie

Might be a bit heavy. I would have gone with a lighter fabric but, without having done a maiden, it's hard to say

Red7fifty

My Feedback: (73)

I bit heavy...but I think it would probably be okay....just don't let it slow down too much.
Will have to wait for your report.
In the meantime, I've been contemplating, getting back to work on mine. lol.

Red7fifty

My Feedback: (73)

If you need to take weight off, you could change out the wheels to either foam, or Kavan wheels from SIG.
The Kavan wheels look like Dubro's, with a chrome hub, but really light, like foam. If you have Rubber wheels on it now, that would probably shave off 6~8 oz.
Your receiver battery.....could that be lightened up?

Those are some easy changes.

If you needed to pull more weight off, you could hole saw some cutout in the fuse sides, and even core out a few spots from the wing......there is a lot of material that could come off. If you core out the wing.....possibly, drill from the bottom, but don't break the top skin. That way, you only have to patch the bottom.....just a thought.

dhal22

My painted KK was heavy enough that I paid the price bringing it around for it's maiden landing too slow. A quick stall on the final turn and in it went.

dhal22

Like all planes roll to an inverted 45 with reasonable throttle and let go of the sticks.

Red7fifty

My Feedback: (73)

Crap....how bad is the damage?
I built a Kobra over 20 years ago...it was my "trainer".
I hit a pole on landing, sheared the wing in half. Rebuilt the missing part of the wing, flew next weekend, sheared the other half of the wing. Rinse repeat this 3 times.
Then, I was able to avoid the pole on landing.
lol
I still have the plane, and I fly in once a decade.......

Quikturn

My Feedback: (12)

Long ago, I learned that my Kobra does not land like a trainer. It had an O.S. Max 35 and was monokoted. If I didn’t carry some power & extra speed to the runway it would just drop before I expected it to.

The King Kobra’s pictured here look awesome all glassed and painted up but with the extra weight they need to be flown more like jets.

coleboom

Update I still haven't flown this BUT this is the ugliest build I have ever done.. The clear Poly has yellowed and there is no consistancy in thickness therefore... yellowed areas and NOT yellowed areas... It looks horrible... Still I will fly it as is rather than sanding it all off. I also took the time to balance it... it took way more lead in the nose than I would have liked... I did actually weigh it though and it is just under 9 lbs. So..... Thinking I will just fly it fast. I don't really like coming in like a bullet. but I can... also thinking I will keep the CB back thus aiding me in keeping the nose up

Hydro Junkie

If I'm right, your initials CB means center of balance. IF that is the case, YOU DO NOT WANT IT TO BE TOWARD THE BACK!!!!!!!!!!!!
The center of gravity needs to be set so the plane will be slightly "nose down" when on a balancer. This is for several reasons:
1) It will help in recovering from a stall. A plane set tail heavy will normally roll to one side where a plane that is slightly nose heavy will normally just drop the nose to recover
2) It will make the plane more sensitive to control throws. With a tail heavy condition, the plane will be be be more apt to try to climb with the slightest of up-elevator and be resistant to diving. This can be fatal to the plane if you get to slow on your landing approach
As you've already said, you built the plane heavy. This means it's going to be harder to land to begin with and, if you only plan to fly it fast, slowing to land is likely to cause it to stall and cartwheel into the ground.
I'm sure others will come up with other issues as well

Red7fifty

My Feedback: (73)

My hunch is the same, balance with C.G. neutral, and drag it in under power if you want to keep the nose up. Balance, holding Throttle, and Elevator (like a Ducted Fan), if you want to drag it in......the wing washout, should allow it to come in nose high.
Looking forward to Maiden report....I love Maidens.........they are fun to me!

Red7fifty

My Feedback: (73)

When I finally get around to finishing mine....I guess I'll go with my Ultracote, instead of the 3/4 oz glass......I had planned to glass and paint for a smoother finish...but, if it's going to add the weight (which I think it will handle fine...it's a thick wing)...it will save me the hassle and mess.

coleboom

I am not a novice so I get what you were saying I meant CG and just typed the wrong thing... b and g one key apart.
the manual talks about a pretty wide cg range and also says that these are all nose heavy.. I prefer my models less nose heavy and don't mind if they are a little touchy attitude wise... here is a pic of my latest build to prove I actually do have some skills

Red7fifty

My Feedback: (73)

Looking at the photo again.....reminds me of how clean of a design this airplane is......helps motivate me to finish mine.
In the air.....no one will notice the yellowing......especially when it zips past at 95 mph.

Hydro Junkie

Many of the people that read these forums are either building or total novices so I tend to make my posts with that in mind. That being said, I'm looking forward to seeing a picture or two of your plane in the air.
Happy Flying

coleboom

I didn't add the pic this is of a Balsa USA smoothie XL I just finished

Anyone have any advice for me on prop selection on the King Kobra with os 75ax and Jett muffler... I want it to go fast


alsa USA Smoothie XL just finished

coleboom

I think mine came out this heavy because I used Glass and Polycrylic. I put the 1st coat of polycrylic on at the same time as the glass... so wound up using a lot to get it to stick... It sunk in to the balsa..... if you do glass I would recommend you seal 1st. coat and wait 24 hrs or so Then glass

do335a

Your left hand is improperly placed.

Photoshop can fix that in a jiffy.

coleboom

Your left hand is improperly placed.

Photoshop can fix that in a jiffy

This was done for me by a friend... If you look closely you will see he put in a shadow, so he is not trying to represent me touching the plane

jollyroger

My Feedback: (6)

I came across a King Kobra kit at the Toledo Show for $85.00 ....should bought it. A couple hours later it was gone. Found it down the hall of the mezzanine for $125.00. You can buy a new one for just under $130.00