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"Cox Tee Dee .010"



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Question on 049 engine choice

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Question on 049 engine choice

Post  rainyday101 on Sun Apr 30, 2017 11:12 am

I have been out of RC and control line since my youth and I am bit older now.  I am building a couple of Ace Whizard short kits from Balsa Workbench.  I am wondering what to power them with.  I currently have a new Texaco I got off the bay.  I also have the Cox 7 x 3.5 props for this.  I have been told by Rob at Balsa Work bench that this will work good for the plane.  For the second and third plane I am struggling with what to uses.  Options I am looking at:

Black Widow with a Killer Bee back plate with an external Sullivan 1 ounce tank.
Killer be as sold by Select Hobbies with an external Sullivan 1 ounce tank.
Tee Dee 049 with an external Sullivan 1 ounce tank.

The Whizard plan shows a Tee Dee.  I prefer reedies.  I want external tanks for longer flight time.  I am worried a Sure Start or would be bit under powered for this setup.  Hence as you see I am looking at higher output reedies.

I prefer the top two options but am open to suggestions.  For any of the options I would also like to go with a Galbreath head set up.  I would also like a throttle sleeve to make these 3 channel.  In my youth I flew all 2 channel RC, but now I couldn't imagine flying without a throttle anymore.  As my kids will be flying these I like the throttle option.  These will be sport planes to fly across the street from our house over the farm fields for days when we don't have time to go to the flying field.

Don't be too hard on me, I have been out of 1/2A for 30+ years.  I am done with electric and coming back home! Flying
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Re: Question on 049 engine choice

Post  roddie on Sun Apr 30, 2017 3:01 pm

Hi there, I also like the Cox .049 reed-valve engines. I think that you'll do fine with your choices. I've ran the Killer-Bee backplate.. and had some fuel-draw issues. These could have been caused by my tank though. I had made a small (6.8cc) rectangular tin tank with uni-flow venting for running 1/2A C/L profile-proto speed. The KB back-plate has a LARGE air-intake.. which directly affected a "suction-only" fuel-draw. If the engine runs-off an exhaust-prime.. but won't stay running; look for air-bubbles forming in the feed-line. This is a tell-tale sign. In my case, I solved this issue by running a larger-size silicone fuel-line from my tank to the nipple on the NVA. The larger line is less-resistant to flow under a suction-feed scenario, than a small ID line. Small-size/half-A fuel-line was too small in my case.

The larger-fuel-line needs to be compressed to fit tightly on the smaller fittings. This can be done by cutting short pieces (5/16" length) of alloy tubing; brass or aluminum having a slightly smaller OD than your fuel line. The ends of the larger silicone fuel-line can be "twisted-into" these compression-sleeves.. which effectively reduces the inner-diameter of the fuel-line enough to fit snugly onto the smaller fitting on the Killer-Bee backplate's NVA.

You may need to experiment with different sizes of fuel-line/alloy tube-sleeves to find a good fit. If you have some 7/32" to 1/4" OD alloy tubing.. (common K & S sizes).. that would be a good starting-point.




Here's a photo of what worked for me. Both; the fuel-line and the alloy-tubing have OD's of 1/4".



This helped me.. and "may" help you with your Sullivan tank set-up. Most people run pressure-bladders with the KB back-plate.

As for throttle-sleeves.. I can't offer much advice on what to do there.. but you'll want a healthy-ported cylinder to take advantage of the high-performance back-plate. Maybe look for a Tee Dee cylinder/sleeve combo. I don't know how well this would run with a Galbreath head vs. a Tee Dee HC head though. I'm sure that someone will chime-in on some things to try.

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Re: Question on 049 engine choice

Post  GallopingGhostler on Sun Apr 30, 2017 3:07 pm

The Whizard would fly with an engine as simple as the Babe Bee. Key is keeping it light weight. Back in the old days of the early 1970's, one might use an Ace pulse proportional single channel radio, flight pack weight a couple ounces including the 2.4V Ni-Cad pack. Nowadays with lightweight RC and lighter weight coverings, multichannel flight is possible. It doesn't have to be the .049 Tee Dee.

Yes, you'd have sparkling performance with the Tee Dee, but remember this plane was originally intended as a beginner and as a sport plane. One doesn't need pylon racer like performance in a sport plane and lazy summer flier. (Although I like the way my 36" Q-Tee performs on a Norvel .061 Big Mig. Laughing ) The Black Widow or even Sure Start would be fine. You may want to go with a hotter fuel with say 25% nitro, although you'd be able to get by with 15%.

On these small planes with reedies, experimenting with props is in order. My 1970's Black Widow flew best with a 6x3 prop, which also coincides with Peter Chinn's advice.

sceptreflight.com / Model EngineTests / Cox Black Widow

The throttle sleeve is a good choice. I used one on my Q-Tee as single channel in the late 1970's with a Black Widow on quick blip sequential auxiliary throttle (Lo-Med-Hi back to Lo). Sleeve without muffler doesn't inhibit SPI, so it works just fine. (SPI - Sub Piston Induction, the location where piston rises above the exhaust port opening a hair to allow a puff of cold fresh air into the crankcase to mix with the fuel air mixture there, increasing power output.)

Also, the Sure Start should work well with the throttle sleeve. Back in the 1980's, I flew my 36" Sterling Minnie Mambo with a throttled .049 R/C Bee. It was basically a throttled Sure Start with integral larger plastic tank. Main thing with using a separate tank is to keep the fuel line as short as possible, as these engines have weaker suction when compared with larger engines. A shorter line ensures more consistent fuel draw. Since the Sure Start doesn't have SPI, it can be used with the throttle sleeve muffler.

However, mufflers do take away horsepower, so if you fly where mufflers are not required is better. Also, you may already be aware of this, but these exhaust throttle sleeves are non-proportional in action. With exhaust port about 1/3rd open is half throttle.

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Re: Question on 049 engine choice

Post  pkrankow on Sun Apr 30, 2017 5:10 pm

If you feel like drilling a bee tank or backplate for the external tank there are the Ace throttles available through Coxengines.ca
https://coxengines.ca/throttle-for-cox-049-engine-bee-style.html

There are also exhaust throttles and more.

Phil
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Re: Question on 049 engine choice

Post  getback on Sun Apr 30, 2017 7:36 pm

Black Widow with a Killer Bee back plate with an external Sullivan 1 ounce tank. Killer be as sold by Select Hobbies with an external Sullivan 1 ounce tank. wrote:
This will work for you run you a 4.75x4 prop and then 5x3 for your kids //?? Good to hear there involved !! If thats not enough just add a TD pis/cly set to it and you will bee good . Got the pretty much same setup and the 4" prop will get U round 20K!! O hea WELCOME BACK!! This Site Rocks!
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Re: Question on 049 engine choice

Post  rainyday101 on Sun Apr 30, 2017 8:00 pm

Below is what I am thinking of building instead of buying.  Opinions appreciated!  Parts from Ex Model Engines or Bernie. Not shown, I will be using a Galbreath head and plug.



Tee Dee cylinder and piston with SPI

Features:
Red Anodized Bar-Stock Aluminum Crankcase
Killer Bee Style Balanced Crankshaft
Stainless Steel Thrust Washer
Large - No Drag Driveplate
New Customized Cox Items


Features:
Durable Nylon Material
High Performance Mylar Reed
High-Flow Air Intake Design
Vibration Resistant Needle
New Original Cox Items




Last edited by rainyday101 on Sun Apr 30, 2017 8:19 pm; edited 1 time in total
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Re: Question on 049 engine choice

Post  rainyday101 on Sun Apr 30, 2017 8:14 pm

getback wrote:  This will work for you run you a 4.75x4 prop and then 5x3 for your kids //?? Good to hear there involved !! If thats not enough just add a TD pis/cly set to it and you will bee good . Got the pretty much same setup and the 4" prop will get U round 20K!! O hea WELCOME BACK!! This Site Rocks!

I came back 2 years ago with Dollar Tree Foam and electric. That was fine for getting the kids started and teaching them to fly. I get tired of charging made in China lipo batteries all day that can burn down your garage. Unexpected motor starts from no name cheap speed controls also livened things up a bit. Now it's time to fly planes that make noise. Land the plane, let the engine cool, refuel, fly again, and again. Wipe the plane off and call it day. No need to spend the next 8 hours of life charging batteries.

My kids are 11 and 8 and love flying with dad. They are actually do quite good with their flying. The 11 year old can land and the 8 year old is getting close to landing. Their landings can get hairy though with a little last second disorientation when facing the plane. I have Tactic radios with the wireless trainer link and take over when things get hairy! They can both fly around the pattern and do an occasional loop and roll.

I am a kit/scratch builder that likes simple good flying rugged planes. I don't build anything exotic just simple quick building planes. The kids help build a little here and there in short spurts.

I am glad to be back!!!
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Re: Question on 049 engine choice

Post  Kim on Mon May 01, 2017 7:05 am

And also, -WELCOME TO THE CEF!!!!!- to you and your crew!!!
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Re: Question on 049 engine choice

Post  Oldenginerod on Mon May 01, 2017 7:21 am

rainyday101 wrote:

Tee Dee cylinder and piston with SPI
I got one of these from Bernie.  If you're looking for a power boost, this is your cylinder. I put one on an otherwise standard Bee engine (apart from HC head) and ended up pulling over 24,000 rpm in the Tach Race.

Rod.
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