Sacrificial Wen-Mac Kingcobra

Thanks for that link Eric, I see a few of my pictures there. Also some of Mark's.

That must be one reason for the removable landing gear George, flatter boxing. The early models as I mentioned had fixed inside the fuselage gear. Good price on the one you linked, NIB and including the ejecting pilot.

Bob

getback wrote:Just got around to reading this one and Bob you're doing a really good job on repair for a salvaged old beat up plastic plane , it's looking nicer as it goes ! Looks like all these planes have the landing gear swept back like that ? https://www.google.com/search?q=wen+mac+king+cobra&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwijrLiz9oXTAhXJOiYKHbo6BPcQsAQIJg&biw=1600&bih=770#imgrc=K3d_JbULdBGUSM:  

Ditto.. I just got round' to reading this thread this morning too. My gawwwd Robert.. you have the patience of a SAINT. I wouldn't/couldn't have repaired that elevator. Good job man! I was reading from your first post.. and thinking; this ain't gonna' be an easy fix.

This post has been an "on and off" afternoon's work. It's a beautiful mild and sunny day here in N. Smithfield, RI.. so I've been "in and out" doing some lawn clean-up and putting the Winter away.. hopefully until next..

I probably would have tried to re-make the whole stab/elev. assembly from balsa and hinging-it together conventionally.. but then there's that centrally-located horn, which would require making a new horn from brass-sheet, and soldering it onto a u-bent music-wire elevator-joiner.



I admire your replicating the original-design.

I'd personally discard the old fuel tank though. No telling the crap that's in there that could clog-up the feed-line or foul the needle. Maybe you could use your moto-tool with a "cutting-disc" to slice-through just the top of the tank to open it up. I'm surprised that the engine can draw fuel reliably from the original set-up. If the tank looks reasonably clean inside.. you could just cut another top-plate of sheet styrene and re-plumb it as the original with plastic tubes.

This made me think of an idea for fuel-tank flushing.. but I'll post that in a separate thread.

I've never had a model airplane with a tricycle-gear. I can understand your concerns with the main-wheels being so close to the wing's T/E. The model appears to sit "tail-low" That's not necessarily a bad thing. It will assist in lift when you're launching R.O.G. If the nose-gear is angled.. you could adjust the entire gear-angle to raise the model up a bit.. and still maintain the model's angle of attack. Lock the mains in a vise.. and bend both legs so that they clear the wing by a safer-margain. Use a protractor before/after to check/record the angle. Try to match the "stance" when adjusting the nose-gear.

You mentioned wanting to try a launching-stooge. That's something that needs some thought.. for the best application to "this" model. Although I've not built one yet.. a "U-type" stooge that cradle's the fuse; just forward of stabilizer's L/E would be the way to go .. I think. You'd need to study these photos, to understand it's function/construction. You could easily build it.. or buy it from "Brodak" if still available.







Well-worth the effort to build/expense to purchase; as it would serve to launch many a conventional C/L model without the need of a pitman.

My models are all "tail-draggers" that utilize a "pin-link" in some fashion. I've drilled a hole in a tailskid.. added a tailskid with a hole for a pin.. and also clipped a safety-pin or made a music-wire link to fit onto my tail-wheel's gear-strut to engage a stooge-pin.

My Rare-Bear's tail-gear music-wire pin-link..




My Cox PT-19's pin-stooge link..



My Cox Cosmic Wind's tail-skid.. shown with an optional fiberglass window-screen "tab" that can be attached/glued onto the tail. (I used a paper hole-punch to make the hole.. a super-simple link for a tail-dragger..)



Here's Eric's adaptation of the Brodak type.. (I want to make one of these..)




Hopefully.. you'll have a pitman, but I never had one when I was flying regularly years ago. I had to be inventive. Necessity has always been the mother on invention. I'm not claiming to have invented the launch-stooge.. but I hadn't known about them.. prior to making my own.

I like that engine! It cleaned-up beautifully! I'm sure that you'll find an easy-fix for the NVA. You should run that one IMO. Better that the old/brittle prop broke when it fell. That was an accident waiting to happen. Do you have any newer props that are close the diameter/pitch of the original? Maybe a Cox 5d x 3p? You can always ream the hub if the engine's prop-screw is bigger.

Bench-run a few tanks of fuel. Use a graduated syringe to gage the fuel-tank's capacity. Time the runs.. and adjust the fuel-amount to a preferred-duration of flight; taking into consideration "cold-starting/tuning".. and the time taken to actually release the model for roll-out.

I hope that the maiden goes well. What's the recommended line-length? It's advisable to stay within that spec. Make sure that "all" three gear-wheels are free-spinning.. and treat the axles with a drop of light oil. Make that part of your pre-flight.. as well as smooth-operating controls with equal up/down elevator throws.

Short-tank it for the first few flights. You'll feel more comfortable knowing that you won't be committed to keeping the model in the air for an extended-time.. until the engine shuts-down. Just a couple of laps will give you the initial feel of the controls. Increase the fuel-volume as you get more comfortable turning-circles.

It's helpful to focus on the background.. rather than the model. You'll still see the model enough to control it. Your eye-focus is what can bring-on dizziness. Remember this. It will help you.

GallopingGhostler wrote:Seems unnatural, Bob, that the rear wheels would be angled so far back. I think it was probably designed such the fuselage was level when resting on wheels. Perhaps a move by the manufacturer, temporarily binding the plane to the box bottom so a thinner profile was obtained by the box to lessen box costs? And over a very long period of time being box kept with model bound by string or tying wire, the landing gear metal wire creped and deformed to a backward position? A key hint may be in catalog photos of the plane.

Not understanding the reddie George, nothing untoward there, maybe someone made a mistake. I hit the + mitigating the reddie. I'm not understanding the need for this feature here!

Bob

roddie, you read my mind on several points. One was the propeller, I have new Cox grays at the ready.

More later, been a long day.

Bob

Yea.. the "red/minus" on George's post must have been a mistake. I personally don't use those buttons.. although I should have given MANY "greenies" over the course of time.   There's still functions/buttons on this forum that I've never explored.

Bob, grain of salt.. I tend to give WAY more advice than can be digested in a single reading.   When I comment; I feel like I'm there with you.. chewing the fat over a good cup of coffee in the workshop!  

I saw that one George, but being used I thought it overpriced. But it is complete and even has the gunsight.

Bid on this one instead:

http://www.ebay.com/itm/used-WEN-MAC-gas-airplane-034-WHITE-BELL-COBRA-034-SELLING-AS-IS-not-COX-or-TESTORS-/112351220053?_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40130%26meid%3D2f64fedc70f2442db10ae0d03f584ecd%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D112351231007&_trksid=p2047675.l2557&nma=true&si=yBzxwTK%252FbFbo%252FMeC0iXaxXtu8Dg%253D&orig_cvip=true&rt=nc

It was $25 to start and I bid $46. Someone nibbled me up to my max and won it for $47. I surely didn't need another, I'm thinking parts, but what made it attractive was that shipping was free.

I read your "fuel tank flushing" thread roddie. It's something I will try, but not on this repaired tank. I'm afraid it's to fragile to sustain much handling. I managed to glue (red tube plastic) the feed nipple back on and replace the fill and vent tubes with brass heated and plunged into the plastic and sealed with more plastic glue.



The heat method works great as the hot plastic molds and adheres to the brass. But I'm not sure about the feed nipple, necessary as the feed tube goes all the way to the bottom of the tank to ensure most of the fuel is picked up. The heat method just dislodges that feed tube, ok for fill and vent though.

Oldenginerod wrote:Hey Bob, it's more than a year since your last post on the Airacobra rebuild.  Did you go any further?

Rod.

Hi Rod,

Yes, I finished it some time ago and posted about it in a thread that has now vanished into cyberspace.

I had to paint it due to the half balsa repaired elevator. Turned out pretty good. I did not use the plastic paint pictured, I painted it with Krylon gray.





And Victor, I have tried to reduce the yellow tint on a couple of my plastic models without much success. I think the only cure is to paint them.

ticomareado wrote:Thanks. Your experience at failure to make it shiny factory white again will probably save me the effort and frustration of trying. maybe some other readers willtell us something we don't know. Now, regarding canopy-- who can vacu-form them for a reasonable price?

Jim and others here have had reasonable luck forming their own using clear plastic from a bottle or other container, making a mold and using a heat gun. I have yet to master the technique.

Bob