TD 050RC's or not?

dosokies Wed Sep 19, 2012 8:11 pm

Greetings Cox engine experts,

I'm a novice poster on this forum, so please bear with me while I learn the ins-'n-outs. I have some questions about two TD 051's that I bought on ebay several years ago (no boxes or papers). The engines appeared to be TD 050 RC's, so I recently decided to disassemble them to verify that. They were supposedly used, but appear to have never been mounted or run. They were both missing the carburetor arms and idle screws, so I purchased new ones for them.

After disassembly, I noted that both had #5 cylinders, and when I checked the SPI - they both had SPI. The exhaust ports each measure about 0.120 in. in height. At this point, I figured they were not 050 RC's.

I then removed the back plates to examine the crankshafts. One engine had what appears to be a HD crank (or "helicopter" crank?). Is that what the 050RC is supposed to have? The other one has a crank similar to the HD crank; but it has some additional material removed from the flange to make it lighter than the HD crank. Photos are enclosed. Both cranks have holes in the crank pins. Both cranks appear to have been made this way originally and do not appear to have been altered from something else. I haven't found any info or pictures of the second crank in any of my searching, so far.

Anyone have any ideas or suggestions about what these engines might be? Are they TD 050's or not?

Thanks in advance for any help,
Ed

The engines

Rear view of crankshafts

Close up of crank#1 and #5 cylinder

Close up of crank#2 and #5 cylinder

View of typical SPI

**RknRusty** Wed Sep 19, 2012 8:25 pm

I'm not an expert on RC engines but I do know that SPI and Mufflers do not agree with each other, since the SPI will ingest spent exhaust gasses instead of clean cold air. The amount of SPI in the picture looks normal for an engine without a muffler, and crank #2 is what I have in my Tee Dee 049/.051 control line engines. There are others here that can give you some answers as to what you have. But to me, it doesn't appear to be a genuine pair of RC engines.

Welcome to CEF, I hope you find us helpful, or at least entertaining.
Rusty

dosokies Wed Sep 19, 2012 9:34 pm

Rusty,

Thanks for the inputs. This forum has been very helpful AND entertaining. It has ignited a passion for the sounds of these little engines that I thought I had lost 50 years ago. One of these days I expect to thrill my RC electric flying buddies with a couple of minutes of dizzying circular flight, hopefully like the ones you post on here (no crashes, please).

I agree with you that the SPI probably disqualifies these engines as the TD 050RC versions, but the crankshafts are what made me wonder. I found the following picture somewhere on the internet, and it showed the HD (or helicopter) crank (same as my #1), but not the #2 one. The crank in the middle, i.e., the "standard " Tee Dee one, is similar to my #2, but there are differences. My #2 has a hole in the conrod pin and the flange is shaped like the HD crank, not round like the Tee Dee standard. All of my Tee Dee's have the standard round crank flange and no hole.

Maybe someone on the forum can shed more light on what is going on with these cranks.

Ed

Jason_WI Wed Sep 19, 2012 9:59 pm

My NIB TD RC05 made on Jul 25 1994 has the same crank as your #2 engine. Yours is almost correct but you should have an unmarked non SPI 051 cylinder. My cylinder is unmarked and does not have SPI. I resisted taking my NIB engine apart......but only for a minute.

TD 050RC's or not? E1eb038aa3bdef2c568bada9de15341c_zps20d1e8a0

TD 050RC's or not? E1eb038aa3bdef2c568bada9de15341c_zps20d1e8a0

TD 050RC's or not? 50bf05e2691ed9af37711b449de0dfaf_zps38fed4f2

TD 050RC's or not? Fe4997ebc379094a6cddd13d7a3ccfc9_zpsa104524c

**RknRusty** Wed Sep 19, 2012 10:20 pm

dosokies wrote:Rusty,

Thanks for the inputs. This forum has been very helpful AND entertaining. It has ignited a passion for the sounds of these little engines that I thought I had lost 50 years ago. One of these days I expect to thrill my RC electric flying buddies with a couple of minutes of dizzying circular flight, hopefully like the ones you post on here (no crashes, please).

I agree with you that the SPI probably disqualifies these engines as the TD 050RC versions, but the crankshafts are what made me wonder. I found the following picture somewhere on the internet, and it showed the HD (or helicopter) crank (same as my #1), but not the #2 one. The crank in the middle, i.e., the "standard " Tee Dee one, is similar to my #2, but there are differences. My #2 has a hole in the conrod pin and the flange is shaped like the HD crank, not round like the Tee Dee standard. All of my Tee Dee's have the standard round crank flange and no hole.

Maybe someone on the forum can shed more light on what is going on with these cranks.

Ed

Ah, so you've been lurking and reading up on us. TD 050RC's or not? Biggrin

Come to think of it, my crank pins do not have holes bored in them. I forgot about that when I posted above. I just went out to the shop to take a look. Hopefully some machinist engine expert got a hold of those and modded them for performance. Though I can't imagine that heavy looking heli crank can help with RPMs. Maybe more torque in the climbs though. Like a heavy flywheel on a car engine resists changing speed between gear shifts and so gives you a better punch when you dump the clutch.

**RknRusty** Wed Sep 19, 2012 10:22 pm

Jason_WI wrote:...I resisted taking my NIB engine apart......but only for a minute.

Haha, so maybe if you put it back together quickly enough it won't remember.

dosokies Wed Sep 19, 2012 10:39 pm

I guess I'll just add some shims under the cylinder and make 'em think they are 050RC's. Then I can call them Faux TD 050RC's...

**RknRusty** Wed Sep 19, 2012 10:43 pm

dosokies wrote:I guess I'll just add some shims under the cylinder and make 'em think they are 050RC's. Then I can call them Faux TD 050RC's...

That'll solve it if you want to use the mufflers. If not, leave the SPI, they'll run a lot faster like that if you use a small enough prop to get the RPMs up to where SPI starts making a difference.

iamplanecrazy2 Wed Sep 19, 2012 11:01 pm

The carb bodies are definitely TD RC 05 parts as they have the little keeper tabs that keep the muffler from spinning around.
Carbs look correct. They could be replacement crank case assemblies to which someone added piston and cylinders they had
on hand.

Surfer_kris Thu Sep 20, 2012 12:54 am

It might just be a case of a late model where they took what they had at hand. There is nothing seriously wrong with the parts though.

Don't worry too much about the SPI, there are several engines that run just fine with it, and Norvel engines are one of those. They are still one of the strongest 1/2a engines around, and throttle well.

The high compression head gives a little too high compression, in my opinion, you'll need to chim that or you can raise the whole cylinder a little if you want too. The only problem I've had with these engines is the muffler, I could not keep mine from vibrating and eating away at the little at the little plastic tab. Another problem is the adjustment of the low end, it can't really be done with the engine running...

Performance is not bad though, mine did/does about 4000-17000rpm on a 6x3 prop (using 10% Nitro);

Surfer_kris Thu Sep 20, 2012 1:01 am

Just remembered another thing. The stock muffler has a big gap between the muffler and cylinder. They might have done that to reduce the muffler backpressure, but it sort of makes the whole muffler redundant. I've sealed the gap on my engine above, and haven't had any problems from that, it reduces the nose and the amount of oil that was pouring all over the engine.

John Goddard Thu Sep 20, 2012 5:23 am

I agree with Jason, having looked at mine.
I'm not sure about the 'whatever was to hand'
Aspect as these engines were made for such a short period
Of time.
I'd say more likely the previous owner has SPI'ed it himself.
Back to the important stuff! Run it without muffler
And enjoy the performance. The Cox 'muffler' is
An interesting description cos they just change the
Pitch a little, they certainly don't make them much
Quieter.
Very Happy

PS
If you want to see how badly an SPI ed 'muffled' TD runs chexk out my TD09 on my Utube.

Surfer_kris Thu Sep 20, 2012 6:15 am

John Goddard wrote: chexk out my TD09 on my Utube.

Where is that then?
When I click on your youtube link I get to "my_videos" not yours... lol!

microflitedude Thu Sep 20, 2012 8:30 am

Wrong video.

Surfer_kris Thu Sep 20, 2012 10:06 am

That didn't really show much regarding the issue of SPI and mufflers.
What are the numbers with and without the muffler? And with/without SPI?

The use of a regular glow plug reduces the power a lot though. That's what is holding back the Queen Bee for instance.

PV Pilot Thu Sep 20, 2012 11:22 am

Well now, this thread just fixed a problem with a RC setup I was trying. Thanks all!.

Have a RC setup TD 049 that I WAS battling a lean scream when the throttle would be snapped shut. To much SPI and actually way to rich. Everything was sealed up properly, but it was getting its own fuel load from being pig rich and breathing on its own with the SPI once the throttle closed. This, along with the fact that Nitro carries its own oxygen.

Had read that the RC 050 muffler also helped with the throttle down and idle, so I was about to tear into my still NIP RC muffler I have.

Apology for the thread jack,,sorry.

dosokies Thu Sep 20, 2012 12:16 pm

Boy!! Lots of good info here. Looks like I will have some things to meddle with and see what happens. Thanks for all the inputs and don't let your nitro get too old...

Ed

John Goddard Thu Sep 20, 2012 6:40 pm

Surfer_kris wrote:That didn't really show much regarding the issue of SPI and mufflers.
What are the numbers with and without the muffler? And with/without SPI?

The use of a regular glow plug reduces the power a lot though. That's what is holding back the Queen Bee for instance.

That's because that vid is a non SPI'ed td09rc running
On song.

The 2 vids before it are a standard spi td09 with muffler
And it runs like a dog.
Take a look
Surprised

microflitedude Thu Sep 20, 2012 7:05 pm

Oops, apologies for posting the wrong video! Embarassed

jsesere Thu Sep 20, 2012 9:09 pm

Despite the engines being sold as .050 I believe they are really .051 in bore.

**RknRusty** Thu Sep 20, 2012 9:41 pm

jsesere wrote:Despite the engines being sold as .050 I believe they are really .051 in bore.

Correct.

Surfer_kris Fri Sep 21, 2012 12:32 am

John Goddard wrote:
The 2 vids before it are a standard spi td09 with muffler
And it runs like a dog.

Are you talking about the video with an 8x4 prop?
You have to at least give the engine a fair chance to rev up...

John Goddard Fri Sep 21, 2012 8:24 am

Surfer_kris wrote:
John Goddard wrote:
The 2 vids before it are a standard spi td09 with muffler
And it runs like a dog.

Are you talking about the video with an 8x4 prop?
You have to at least give the engine a fair chance to rev up...

I ran the 7 3.5 as well Kris it made no difference.
I didn't bother to record it cos It was more of the same.

PV Pilot Fri Sep 21, 2012 9:34 am

Surfer_kris wrote:
John Goddard wrote: chexk out my TD09 on my Utube.

Where is that then?
When I click on your youtube link I get to "my_videos" not yours...

Getting the same thing when I click on your Youtube link John,,

Just added mine to the profile stuff and it seems to be working on mine.

John Goddard Fri Sep 21, 2012 4:58 pm

PV Pilot wrote:
Surfer_kris wrote:
John Goddard wrote: chexk out my TD09 on my Utube.

Where is that then?
When I click on your youtube link I get to "my_videos" not yours...

Getting the same thing when I click on your Youtube link John,,

Just added mine to the profile stuff and it seems to be working on mine.

I put the whole http on this time Keith
give it another go
Very Happy

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