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Bought a Comanche, but as it is 50 years old, needs a little TLC

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Help! Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Thu Nov 09, 2017 8:49 pm

Just as the thread title says, I need to reglue the fuselage studs, and wonder how to have the screws bite into the plastic without freezing on.
I need a rear elevator as the one on it is missing a tab, possibly can make one and glue it on the same way Jay Mendoza suggests.
New tires, as the ones on are fossilized, and a nice clean up of the plane. What products are best? It has a lovely patina, so that stays.
The engine is frozen with the piston on the UP position. Tips?
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Marleysky on Thu Nov 09, 2017 10:04 pm

Tips on the tight engine. Just heard about this one, less messey than the green anti freeze soak. they said to put engine in a plastic zip-lock bad and put it in a pot of boiling water to heat up the old castor. I guess you would  remove the baggie and carefully remove the engine (USE GLOVES) and squirt a few drops of Nitro Fuel on the cylinder slots and see if  it loosens up.  I'd use the antifreeze soak if the engine is really covered in old castor( ran hard and put away wet)   I have, on a mildly castor coated engine, just used a Hair dryer (monocoat gun). Hold the engine in a gloved hand, hold nozzle of hairdryer right on the cylinder, rotating back and forth under High heat until you smell the castor, then set the dryer down and attempt to rotate the prop, very very carefully. If there is resistance, go back and add some oil or fuel to cylinder slots and heat it up again. Once it "breaks free" splash more fuel or oil on piston and flip or spin prop till its smooth. ( My 2 Cents) If you want to get it to run, you really need to clean it up, inside and out, you'll be surprised at the gunk inside an old engine

Larry Renger wrote a very good article on the care and feeding of 049's, located here:   http://www.mccookfieldfac.com/helpful-info/cox-engines.pdf

it is the linc at the very bottom of the page for "Instruction Sheets" on the Left hand column.


Last edited by Marleysky on Thu Nov 09, 2017 10:07 pm; edited 1 time in total (Reason for editing : linc location)
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Fri Nov 10, 2017 9:42 pm

Great tips! The engine loosened up with the hair dryer. Has very nice compression.
I am having a bit of difficulty opening the rear of the crankcase Huh...
Don't want to force and damage...Once open, how is the inside cleaned?
Thank you.

Regards, Alberto
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Oldenginerod on Sat Nov 11, 2017 12:30 am

swift53 wrote:
I am having a bit of difficulty opening the rear of the crankcase Huh...
Alberto

There shouldn't be any problems getting the rear open.  Should just be a matter of removing the four screws and it should come right off, either tank or backplate.  Will probably just be stuck on the gasket.  As for cleaning, if it doesn't look too bad just flush it with a little fuel or alcohol.  Automotive carb cleaner is good too, although a little harsh, expecially if used in place of the alcohol. lol!
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Sat Nov 11, 2017 8:15 am

It is not held by four screws, it is screwed on just like the cylinder...it's a 1.5
Hair dryer?

Regards, Alberto
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Oldenginerod on Sat Nov 11, 2017 2:58 pm

Ah, so you have the Comanche .15. That's a Sportsman 15 engine isn't it? I was thinking of the .049 version.
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Sat Nov 11, 2017 3:38 pm

Yes, it is a Sportsman 1.5.
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Marleysky on Sat Nov 11, 2017 7:02 pm

Sometimes referred to as the “Big Comanche “

Yes, it has the Sportsman 15

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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Marleysky on Sat Nov 11, 2017 7:10 pm

[quote="swift53"]It is not held by four screws, it is screwed on just like the cylinder...it's a 1.5
Hair dryer?

Regards, Alberto[/quote

Here’s the instruction sheet: https://dbabd7f0-a-62cb3a1a-s-sites.googlegroups.com/site/nitroengine/Cox%20Sportsman%2015.PDF?attachauth=ANoY7cqt77vvlaEp0kajTuK2NTpL7M-wtXMySYAD_DGwDlombhWEIxqa5GiJc9DoZzawY-CrdcTlv1Ivz9jHLpkjXQ7rvi_uP3mbfGYnQQyZ5wP9tFswgaBeI8-OfzbAK0WklVUFTW7nbKz4_HQm7Zo0lALgslPXOPoYHmSmhJbKZnoTKFT85LqUFpW8P9tlv6in8Nkw_rJWRanrnmbKLdYVBisa6AbZKQ%3D%3D&attredirects=0


Looks to me like that “rear intake” cover is threaded into the crankcase. So, yes, a little heat will help loosen any built up castor oil varnish.
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Sat Nov 11, 2017 7:25 pm

Great instruction sheet!

Thank you This Site Rocks!

Regards, Alberto
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Help! Big Comanche tips

Post  Madguns on Thu Nov 16, 2017 8:25 pm

I just scored one on Ebay myself. My engine was frozen up as well.

I dismantled the engine the best I could. The hardest part is removing the reed valve assembly. If you don't have a cox spanner for this you will end up nicking the aluminum as I did. No big deal if you do, as you cant see it once installed in the plane.

I got mine off by clamping the engine mounting lug very tightly in a bench vise to secure the engine from moving. I then too channel locks to the reed valve assembly and squeezed very hard while slowly applying torque to remove the assembly. Lefty Loosy.

Couldnt hurt to heat up the engine with a heat gun or liberal use of a torch.

Once you have that off its all down hill.

You can then submerge the engine in Lacquer Thinner over night. Once its had a good soak I then used some penetration oil on the cylinder (glow head off) and let that sit over night. After that was complete I installed an old propeller and turned it by hand to free up the cylinder. It worked.

The other parts need to soak in the thinner for a while to break up the oil. Use a sewing pin to clear the fuel jets on the venturi. I just test ran mine yesterday. It is LOUD. Also bit my finger. I can see why they stayed with the smaller engines after this guy.

My plane has a broken / missing vertical stabilizer so I'm going to make one from polystyrene sheet.
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Madguns on Fri Nov 17, 2017 7:57 am

[img][/img]
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Help! This is my solution for the tatty landing gear on this airplane.

Post  Madguns on Fri Nov 17, 2017 8:00 am

These are the wheels that are available from the Cox Canada Ebay Store.



The new wheels have the tires removed and hubs sprayed with Tamiya Silver, any Silver paint will do however.





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Help! More pics of my Comanche.

Post  Madguns on Fri Nov 17, 2017 8:04 am

Mine had a broken vertical stabilizer. Waiting years for a replacement Fuselage side to appear on Ebay is not an option. This airplane is one of the most beautiful RTF that cox made.





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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  getback on Fri Nov 17, 2017 8:48 am

That is Very special the engine from database ... Sportsman .15 (2.5 cm³)
Manufactured in 1958-1965 (#110)

This engine is similar to the Olympic, but has plain bearings, which resulted in a lower price ($7.98 in 1658, to be exact). The aluminum parts were not colorfully anodized as its stronger brother, the Olympic. Again, Dale Kirn was responsible for the design of this engine which followed the Space Hopper and Olympic design philosophy.

The engine was also used as a product engine in the beautiful "Big Comanche" C/L model. This was the only .15 powered ready to fly C/L model Cox ever manufactured. Here, the engine was equipped with a longer needle valve and a spinne >>>> http://www.mh-aerotools.de/airfoils/cox_frameset.htm Nice !! This Site Rocks!
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  Mudhen on Fri Nov 17, 2017 10:32 am

I don’t think Dale Kirn designed this engine. He started with Cox, (the first time,) in August 1962.
The Sportsman/Olympic and their .049 predecessor, the Space Hopper characterize the third generation of Cox engines and were in development following the Babe Bee/RR-1 from 1956.
This would have been 1957-1960. The engineering department consisted of William Selzer, Cole Williams, and occasionally Mark Mier. Cox followed an evolution of engine design that led to greater and more competitive performance. The idea behind the Space Hopper was mounting a modified version of the carburetor assembly from Thermal Hopper to the crankcase of the Babe Bee. (I have two prototypes of this engine buried somewhere in my home.) In any case, this was before Dale Kirn’s time with Cox. In the fifties Dale was in a traveling control line road show, of sorts, demonstrating Victor Stanzel products.
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Fri Nov 17, 2017 3:36 pm

I think we have something going on. Comanches are great airplanes, there ought to be a section started
that focuses only on these models.

We can share modifications, solution to damaged parts, etc.

Possibly a new thread? Very Happy

Regards, Alberto
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Fri Nov 17, 2017 5:01 pm

Some photos...
dang, don't know how to on this site. Please help!
Thank you
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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  getback on Fri Nov 17, 2017 5:37 pm

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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

Post  swift53 on Fri Nov 17, 2017 6:01 pm

Thank you!

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Help! Re: Bought a Comanche, but as it is 50 years old, needs a little TLC

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