dhal22

thx, no need to respond after a long day at work. and excellent point about the final shape of the aileron. i was attempting to replicate the sanding method that 8178 uses in his blue angel build in the classic pattern forum. he temporarily glues the aileron to the wing and sands both parts to perfection before beveling. i think buying aileron stock is still a good idea though, i could just by it unbeveled.

thanks again. david

btw, beautiful work on your KK.

kelldog

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put a .90 in her! If you want it "and you will" it's there. Better then a ultra sport AND CAN BE VERY FAST with slow and stable landings and flight. No weight gain with a 90. TT 91 with a 12x8 prop on my bird. Kelldog

ExperimentalAviator

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David,

I didn't think about the temp. glue and sand before beveling, but I like that idea.

Thanks for the kind words.

I didn't work today, just spent all day at our new R/C field! http://www.waam.us/

Mike

mobileraptor

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First Off Mike ( ExperimentalAviator)

I want to thank you for doing this build and taking the time and the effort to post it in such a professional manor.

I am returning to the hobby after a three year absence due to a move/relocation. I am currently putting the finishing touches on my new shop and am getting very close to being ready to put something one the building table. Here a picture of my shop, I'm pretty proud of it.



I have been considering several planes to build for my first project, I've looked at several pattern planes and other project and then I thought about my old Kouger with was one of the best flying planes I ever owned until it was taken out in a mid-air.

One of my considerations is my local flying field is a grass runway, I do want a plane with retracts. So I started a search on the Kougers & King Kobras and found this thread. I decided on a King Kobra due to the larger tire size plus the plane will much easier accept retract over the Kouger.

I found the Sig site and it appears that the kit is still available and will call Monday and get one on order.

I don't have a engine in mind yet but I do have a YS-61 sitting in a box doing nothing.

Thanks again for doing the thread and keep up the good work.

John

ExperimentalAviator

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John,

You do have a shop to be proud of, and I’m sure that you are especially motivated now to get that new project underway!

The YS63 will be a good fit on the King Kobra. I also set up my KK for a Satio 91 but will probably never go that route. Take measurements and make sure that you have plenty of prop clearance for the YS63. I set my airframe up to get another half inch of prop clearance over the original design, and in doing so used Spring Air retracts with 3/16� gear legs.

I want get back to working on the KK for several weeks, maybe a month. Between having a new club flying site to have fun at, helping several members with their projects, and doing some preventative maintenance on several of my models, the KK got put on the back burner for the umpteenth time.

I’ll be posting again as soon as I get the project back underway.

Thanks for the positive comments.

Mike

mobileraptor

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Mike

I did have a question about you wing sheeting, I noted that you used Sorghum for you wing sheeting. I also noted the you stated that you had recently started using Gorilla glue and you used it in some of you construction steps.

I have used Gorilla glue for sheeting several foam core wings with outstanding results, mostly on Carden wings. I am wondering why you didn't use the gorilla glue for your wing sheeting.

The only reason I can think of, is the possible migration of the glue into the already constructed landing gear and servo bays.

Also, you noted the use of a YS-63. I mentioned a YS-61 While I love the YS-63 I don't think it would be enough motor for a King Kobra

John

ExperimentalAviator

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John,

I used the Sorghum because I had an unopened container on the shelf. However, I will never use it again now that I have discovered Gorilla Glue. Since sheeting my KK wings I have visited the Carden site and was impressed with the wing sheeting techniques using the Gorilla Glue and will copy that from now on.

As for the Gorilla Glue migration I would be willing to live with that possibility since the overall results would be worth the minor inconvenience of having to clean up a few spots here and there.

Well, I should have read your post with a little more detail! For some reason whenever I hear YS I just assume four stroke engine. A very bad habit for sure, especially since YS has some very powerful two stroke engines as well.

I found this quote on a YS fourm, "I ran the 12X12 and 12X13 props on 10% nitro for nearly two years. I never saw a reason for more nitro. The engine turned these props at nearly 9500 RPM all day long and the performance was outstanding with excellent transistion." If the YS61 will turn a 12x12 prop at that RPM then your KK performance will be really SWEET!



Mike

mobileraptor

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I had a 40 size shrike that I kit bashed to fit a YS-61 rear exhaust on a tuned pipe , running on 30% helicopter fuel it was turning a 12 x 12 prop slightly over 12,000 on the ground. I could hear the engine un-load in the air in a slight dive. It had limited vertical, there reason I say limited vertical is after pulling straight up you only had a few seconds before it got very small.

I still have a rear exhaust YS-61 but a tuned pipe would mess up the looks of a Kink Kobra, I Think[sm=eek.gif]



P.S. I see your from Tuscaloosa, AL, I bet you watching the Iron bowl and routing for Auburn

dhal22

hey mike,

any updates on the KK build?

david

ExperimentalAviator

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David,

I'm sorry to say that very little work has been done on the KK since my last building post in late October. I had hoped to get back on the project in about 3 or 4 weeks but that has not been the case.

I had several weeks’ worth of preventative maintenance to take care of on the rest of my models and after getting most of that done I ended up selling my Yak. Afterwards I spent a good bit of time getting the new owner of the Yak set up with a different engine and radio installation.

Let’s see, the Christmas holidays were approaching and then my daughter decided that she wanted an airplane for Christmas; Yeehaa! It was a last minute rush to find an ARF trainer that was available to purchase in the area, and that was not easy since I’m hard headed and wanted it to be a Sig product. We ended up with a Sig Kadet Senior and are in the process of putting that together with a YS-63 for power. We hope to have that ready soon!

After the Kadet Senior gets airborne, and my daughters flight training begins, I will get back on the KK project. I did finalize the nose gear installation so the worst is behind me. I should be able to get the KK ready for cover in short order once I can refocus on the project.

Mike

Tango Juliet

That's so nice. I couldn't get either one of my kids interested when they were younger. I hope she developes a lifelong affiliation with the hobby. We need more girls!

dhal22

glassing and applying polycrilic is where i'm at right now on mine. i should have primer photos in a week or so.

david

Tommygun

My Feedback: (2)

This has become my favorite plane. You'll love it. I bought this one prebuilt in a 70's orange and black color scheme. After flying it for a while with a .61 FX, I shoehorned in an OS .91 FX with a tuned pipe. It hauls pretty good. The unlimited vertical is awesome; goes until I yank the throttle back. The only problem is it has a voracious appetite for fuel- I can go through a gallon in a day easy. I was thinking about building one, or possibly redoing this one with a painted fuse and retracts. Are you going to use some kind of polyester resin and fiberglass cloth to cover the fuse? Can that stuff go over the plastic turtledeck?

ExperimentalAviator

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Tommygun,

You can safely use epoxy resin on the plastic turtle deck.

Epoxy is my preferred resin due to the long work times available with slow cure hardeners and the smell is generally not too offensive. I don't use polyester due to the harsh smell and short work time before the resin cures. Also, polyester will eat the white foam in the wing, so you would have to make sure that the resin did not soak into the balsa fibers too deep and attack the foam.

A ¾ or 1.0 ounce weight fiberglass cloth should be more than sufficient to give the airframe a durable surface.

Look in the RCU Composite Forum for a lot of good information.

Mike

ExperimentalAviator

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After a long delay I had some time to work on the King Kobra project.

Mike

ExperimentalAviator

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More pictures.

dhal22

glad to see the project is back on track. i wondered if i would see a progress update someday. i also have mothballed my KK. it is essentially ready for paint. the wing is primed and sanded to perfection. the fuse is awaiting my decision on whether to paint, dye or leave the canopy clear. i also want to get some more painting practice elsewhere 1st.

looks good, please keep us posted on additional progress.

david

David B

Glad to see you back at it, ExperimentialAviator. Your photos & documentation are second to none. Great job, we appreciate your efforts! This plane is definitely on my list.

SPLIT S

Here's a couple of pics of mine before her maiden. I took the ST G75 out and installed an OS 75AX before the maiden. Great flyer and really looks sweet in the air. Only wish I would have put retracts in mine !!!!! Nice job with yours........

Dan

I don't know why the pics remain small, you can see the full size in my gallery.

David B

Mike,

How are the wing halves joined? Are they simply butt glued & a fiberglass strip used at the joint? I didn't see a spar & I'm sure you would have included a photo of it's installation.

David B

Flyboy76

My Feedback: (14)

Your detail in explaining this build is incredible. The section on the foam cores could be used as a tutorial. I will be attempting to build a CT-114 Tudor from RCM plans this winter and seeing how you did yours was invaluable. Please keep up the progress updates!! your attention to detail is amazing.

cheers

geoff

dhal22

my wing halves were butt joined with polyurethane glue and glassed afterwards with the provided fiberglass strip. then again my whole wing is glassed. but to avoid hijacking this thread my building work can be seen on my thread "anyone building a king kobra".

heavy blue paint tape will stretch if you pull hard enough during the assembling and gluing of the wing halves. this is great for preventing the expanding glue from pushing the wings apart.

david

ExperimentalAviator

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Thanks for all the positive comments. It's good to be carving and sanding balsa again!

Dan, you did an OUTSTANDING job on your KK! How is the performance with the OS 75 AX? I have been keeping up with your project and glad to hear that your KK test flight was a success! I just ordered a new batch of Aeropoxy resin from Aircraft Spruce and ordered cloth from Aerospace Composite's. I still have to order the UPOL High 5 Gray Primer. I hope to get my KK glassed and primed before winter sets in!

If I had this to do over again I would have built my KK with fixed gear. I don't mind retract installations in built up wood wings but working these into a foam wing was a chore that I could have done without! But, as is, I'm looking forward to the high speed fly-by's with the gear tucked away and the engine screaming with the MAC's tuned pipe.

David B, the wing halves are butt glued as David (dhal22) described. I used 30 minute epoxy. I have not applied the center strip of fiberglass at this time. I have to remove a section of the wing leading edge for the nose gear, then fiberglass the center section, then line the wheel cut-out with wood. After that the wing will be ready for covering.

Don't worry about hijacking the thread! As I said at the beginning, anyone should be welcome to chim in.

Mike

ExperimentalAviator

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More pics.

ExperimentalAviator

My Feedback: (15)

More pics.