Tee Dee 049/051 Needle Valve Body - Testers Wanted!

Tee Bee wrote:Thanks guys! It's nice to see someone put the effort into making quality parts so we can keep these little engines running into the future.  

Andrew, you have a good memory regarding that plane and it's wing.  I remember receiving a couple of PMs back when I had the build thread going that suggested I not build it as drawn or try to fly it with that airfoil.  Here we are still flying it over 7yrs later.  I'm sure that those naysayers probably aren't capable of having much fun in life unless things are going just right.  Some of the planes I have flown the most over time have unusual characteristics(character!) and some of the smoothest flying, well designed models get a little dull after a while.  I enjoy the variety this hobby allows, rather than being stuck in a rut of doing the same thing everyone else is doing all the time.  The fastest and most efficient is not always the most fun.  I would think anyone still flying Cox engines in this era of super efficient electric power setups should get that.

AMEN!!!

Well, I sent Matt my initial results, but I’ll go ahead and post them here also.  My test mule is a broken in TD.051 engine.  In the picture is a standard Cox needle/venturi on the left, Matt’s setup on the right, and the test mule with a Texas Timers fine needle assembly mounted.   Ignore the Texas Timers needle body, I won’t do anything with it other than swap it out and won’t say anything more about it.




Here’s what I have so far.  I did the tests Saturday afternoon.  The test engine has a standard Cox high compression glow head and two glow head gaskets.  Temperature was 87 Degrees, and pressure was 29.99.  Don’t know what the humidity was, but it hasn’t rained here in 25 days.  I used a yellow Cox 5x3 Rubber Ducky prop as I like the visibility.  Less chance of putting my fingers in the prop arc when tweaking.  I used the new formula Cox Super Power Fuel.  25% Nitro as that’s what the local hobby shop was carrying.  

I started with the standard Cox needle and venturi for a baseline before switching to the EX venturi and needle.  The Cox datasheet says to start the engine at 4 turns open, so that’s where I started, and then leaned it out to peak at 2 5/8 turns open.   That got me 20,750 RPM.  Here is the setup with the balloon tank I used for the suction tests.




Then I swapped in the EX venturi.  Trial and error showed that a good starting point for mine is 6½ turns open, and then down to a peak at 5¼ turns.  That got me a max of 20,900 RPM.  Not sure why I’m peaking 1¾ turns less than Tee Bee.  Needling was fine as it had a wide range from rich to peak.  Since it’s a friction fit with the spring and plastic spray bar seal, it does needle a bit better than the click style of the OEM Cox needle.  Mine isn’t sensitive on the needle like Tee Bee’s is.  I do see a large difference in fuel head according to the tank (balloon) position, but all TD’s are like that.  Although I do believe Matt’s is a little more sensitive than the stock assembly that I used.

I was skeptical that it would be able to run on a bladder as the needle is a coarse thread, but since it starts at 6 ½ turns out and runs at 5 ¼ turns open, I went ahead and tried it anyway.  After playing with it for about a half hour, I got it to run on a Texas Timers bladder setup.  It ran at 1¼ turns open at peak.  Still the same 20.9K RPM, but that’s physics.  Since it’s a coarse thread it only had about ¼ turn of travel from too rich to run to too lean to run.   After I figured out how to get it started and running reliably, I went ahead and filled the bladder with an ounce of fuel to see how steady it would run. It kept a steady RPM, and was consistent enough that I’d have no problem flying with it, but that ounce only lasted a little over three minutes…  Maybe one of the other beta testers is a bladder guru and can get a better needle from Matt’s setup.  Here’s the bladder rig I used.  That Dubro four ounce tank is pretty good for holding the bladder.  Hopefully, if the tubing ruptures, it won’t spray all over me.




I’ll try a different glow head setup and vary the number of head gaskets and see what I can get.  I figure I’ll try the glow head insert and adapter with five gaskets to start and see where I can go from there.   The Tee Dee .051 datasheet says I should get around 23,000 RPM on a 5x3, so I have room to work here.  Once I get things where I like them, I’ll throw the engine on a plane and do a flight report.  I’ll update Y’all as I go.

The Stoichiometric Mark

Interesting to see the differences in your testing. Seems each of my Cox engines have slightly different personalities in how they start, tune, and perform in the air. My tests were done on a hot(mid-90s) and very humid day on the TX coast. In cooler, drier air, my needle settings will surely be quite different. My TD generally runs about 5mins on a 1oz vented tank. I have another TD .049 flying with an exhaust throttle that will run 7-8mins with throttle management with the same tank setup. I'm curious to try the new NVA on that engine for comparison. I'm about to leave town for a bit, so further testing will have to wait.

Just to say Tee Bee and Mark ya'll are doing a Fantastic job of analyzing this product ,and am happy to hear it is working out well. Tee Bee with the setup on the Das splat the fuel draw is definitely working good with the tank/hose being much lower than the engine mount . Matt. !

Thanks again for the excellent detailed feedback. Still waiting on a few more testers and will share their results if they do not post directly. The bodies themselves have been run at this point.

Good deal, Matt. Thanks for the NVA and for motivating me to get out and play. Seems my box is filling with EX parts lately.

Getback, just because the fuel line loops downward, it doesn't represent the tank height. It's as high in the fuselage as reasonable. Besides , the engine is running and flying fine after some break-in. The biggest limiter of performance is the brutal summer weather we're having.

Nice results so far. Still waiting patiently for a package to arrive. I'm all set up and ready to go. Got the engine out and it was happy to hear it was going to breathe once again...

Hi, I appreciate all the information and experience that the users who have received the pieces of EXModelengines are doing. I am waiting for the arrival of Mr. Matt, I hope the postal service of my country will deliver it to me on time!

Here my experience then, first of all, I thank Mr. Matt this possibility that gave me to participate.
The first video shows the behavior with the original needle spring.
The second video shows how it behaves when the neoprene tube holds the needle, (in which case the spring was discarded for testing).

Video 1:

Video2:


These were your concerns .....
Approximate needle setting (rich, lean, etc.)
Driving range, 5 turns "fat" - 4 1/2 "fine". In 4 1/2 turns the motor works with the speed regulating ring between 7500 and 12700 rpm
Needle sensitivity (how difficult was it to dial-in)
The needle seems to have some play and is not thin at the time of adjustment. (It has micro movements) causing the engine to change.
Another problem that I detect, is that the spring when adjusting the needle, does not remain in the desired place, therefore can not be adjusted with that design perfectly.
Ease of use:
It would be interesting to make a factory mark on the needle to control the number of turns that open or close.
I had to make a mark on the needle with indelible ink in order to control the number of turns.
Anything else you wish to note:
I had to replace the original spring with a neoprene tube to let the needle set in the desired position. The original spring is discarded in this test.
The entire assembly fits perfectly to the engine even when a speed regulating ring is used. There are safe and sufficient spaces for everything to work properly. To see photos nr: 2444 and 2446.


Fuel Used:
25% Nitro
20% Ricino
Other Methanol
Propeller Used:
Cox Gray 6x4
Conclusion:
Mr. Matt with all my respect, I suggest you see how to hold the needle to avoid unwanted movements, which make the motor uneven march.
I also suggest making a mark on this needle so as not to lose control of turns when operating the engine.
(Note: information checked by Mr. Matt.)

MauricioB wrote:Here my experience then, first of all, I thank Mr. Matt this possibility that gave me to participate.
The first video shows the behavior with the original needle spring.
The second video shows how it behaves when the neoprene tube holds the needle, (in which case the spring was discarded for testing).

Video 1:

Video2:


These were your concerns .....
Approximate needle setting (rich, lean, etc.)
Driving range, 5 turns "fat" - 4 1/2 "fine". In 4 1/2 turns the motor works with the speed regulating ring between 7500 and 12700 rpm
Needle sensitivity (how difficult was it to dial-in)
The needle seems to have some play and is not thin at the time of adjustment. (It has micro movements) causing the engine to change.
Another problem that I detect, is that the spring when adjusting the needle, does not remain in the desired place, therefore can not be adjusted with that design perfectly.
Ease of use:
It would be interesting to make a factory mark on the needle to control the number of turns that open or close.
I had to make a mark on the needle with indelible ink in order to control the number of turns.
Anything else you wish to note:
I had to replace the original spring with a neoprene tube to let the needle set in the desired position. The original spring is discarded in this test.
The entire assembly fits perfectly to the engine even when a speed regulating ring is used. There are safe and sufficient spaces for everything to work properly. To see photos nr: 2444 and 2446.


Fuel Used:
25% Nitro
20% Ricino
Other Methanol
Propeller Used:
Cox Gray 6x4
Conclusion:
Mr. Matt with all my respect, I suggest you see how to hold the needle to avoid unwanted movements, which make the motor uneven march.
I also suggest making a mark on this needle so as not to lose control of turns when operating the engine.
(Note: information checked by Mr. Matt.)

Excellent - thanks!

EXModelEngines wrote:

MauricioB wrote:Here my experience then, first of all, I thank Mr. Matt this possibility that gave me to participate.
The first video shows the behavior with the original needle spring.
The second video shows how it behaves when the neoprene tube holds the needle, (in which case the spring was discarded for testing).

Video 1:

Video2:


These were your concerns .....
Approximate needle setting (rich, lean, etc.)
Driving range, 5 turns "fat" - 4 1/2 "fine". In 4 1/2 turns the motor works with the speed regulating ring between 7500 and 12700 rpm
Needle sensitivity (how difficult was it to dial-in)
The needle seems to have some play and is not thin at the time of adjustment. (It has micro movements) causing the engine to change.
Another problem that I detect, is that the spring when adjusting the needle, does not remain in the desired place, therefore can not be adjusted with that design perfectly.
Ease of use:
It would be interesting to make a factory mark on the needle to control the number of turns that open or close.
I had to make a mark on the needle with indelible ink in order to control the number of turns.
Anything else you wish to note:
I had to replace the original spring with a neoprene tube to let the needle set in the desired position. The original spring is discarded in this test.
The entire assembly fits perfectly to the engine even when a speed regulating ring is used. There are safe and sufficient spaces for everything to work properly. To see photos nr: 2444 and 2446.


Fuel Used:
25% Nitro
20% Ricino
Other Methanol
Propeller Used:
Cox Gray 6x4
Conclusion:
Mr. Matt with all my respect, I suggest you see how to hold the needle to avoid unwanted movements, which make the motor uneven march.
I also suggest making a mark on this needle so as not to lose control of turns when operating the engine.
(Note: information checked by Mr. Matt.)

Excellent - thanks!

Thank you Mr. Matt for allowing me to participate. I have left my best impression so that your product is of excellent quality and meets the satisfaction of its customers.
If you need anything else and I can be useful, just let me know.

Good Testing Mauricio , it is strange you had issues with the seal in the NVA when no one else said they did? Wonder if they're all not coming out the same off the product line ? I have had problems with the used and older nva's but not in new ones , may just bee me though.

getback wrote:Good Testing Mauricio , it is strange you had issues with the seal in the NVA when no one else said they did? Wonder if they're all not coming out the same off the product line ? I have had problems with the used and older nva's but not in new ones , may just bee me though.  

Hi Eric, hi Roddie, what happens with the needle that I received, is that it is trapped by the spring (see Video 1 - minute 1.30), as Roddie says, just place a neoprene and remove the spring so that The needle remains in the desired place, in its turn the neoprene seals the possibility of undesirable air sucking.
My proposal to Mr. Matt is that this is solved from the factory, so that the customers have already solved that detail and do not have to be devising a way to solve it. That is the purpose of this test, to find possible faults if there were and solve them.
Roddie, I also placed some flat washers in some of my engines, but sometimes the neoprene is also necessary because in some cases there is air sucking.
It is seen that in many designs is an O'Ring to avoid air intake and also a steel tongue to hold the needle, that is still the safest.
The vibrations typical of the engine often means that if there is no steel tongue that locks the needle, the needle begins to move according to the RPM of the motor by vibrations.

getback wrote:Good Testing Mauricio , it is strange you had issues with the seal in the NVA when no one else said they did? Wonder if they're all not coming out the same off the product line ? I have had problems with the used and older nva's but not in new ones , may just bee me though.  

Yes, all parts were run together and all assembly completed by myself.

I suspect one of the issues of the seal is the plastic friction seal. These are notorious for being somewhat inconsistent, even brittle with age. I will do some testing on them to ensure reliability and explore what Roddie had mentioned. Additionally, using nylon as a type of bushing may be a cost-effective way to alleviate further leaking concerns.

Thanks again for all the feedback!

Just got in and got my package in the mail. It looks great. If all goes well and I am mobile tomorrow afternoon, I will be able to try it out and run this stuff! Anyways, stay tuned.

NEW222 wrote:Just got in and got my package in the mail. It looks great. If all goes well and I am mobile tomorrow afternoon, I will be able to try it out and run this stuff! Anyways, stay tuned.

Hi, I'll be listening to your experiences !!

roddie wrote:

MauricioB wrote:
Roddie, I also placed some flat washers in some of my engines, but sometimes the neoprene is also necessary because in some cases there is air sucking.

It is seen that in many designs is an O'Ring to avoid air intake and also a steel tongue to hold the needle, that is still the safest.
The vibrations typical of the engine often means that if there is no steel tongue that locks the needle, the needle begins to move according to the RPM of the motor by vibrations.

Yes this is true. It would be very expensive for Matt to reproduce the original-style needle and steel-tab. I think he's probably using product-engine needles/springs/seals which he may already have in surplus-stock. The needle-valve "body", spray-bar and venturi are parts that needed to be made at his expense. It is a gamble whether enough modelers will buy these parts being offered, in-order to cover the expense of the machining-costs for an initial small-quantity production-run.

It is good that you and the other testers are giving some accurate and timely feed-back. This will help Matt to make decisions on how to proceed.

Yes, when looking into the OEM style that used the leaf spring the tooling cost was out of control for the size of a production run. All of these parts to assemble the needle valve body were recently run with the exception of the needle valves which we have a large box of and will most likely bring to my grave lol.

Some of the initial samples that I tested used a standard Surestart spraybar where the hole had to be approximately aligned where the drill would pass post needle valve body / spraybar assembly. This was ultimately hit and miss so a new run of spraybars was done which does not have the hole pre drilled.

Matt

Ok. So made a bit of time today to do some running in. Here are th estats as of the time of running the engine.
Temperature:
73.9°F
Dew point:
59.4°F
Humidity:
60%
Humidex:
81

Location is approximately 803 feet above sea level

Items used:
Really well run in and abused TD .051
Cox 5 x 3 Black propeller w/o safety tips
1 head gasket
TD glowhead
20% Sidewinder fuel with added castor
Homemade hotel shampoo bottle clunk tank
Balloon Tank

First, the installation of the new parts. All went well and smoothly except for one thing. The fitting of the venturi into its hole in the spraybar. On my test piece, the venturi only went in one way completely. If I put it in the other way, it would not completely seat itself and not be able to needle at all. I think if one was to drill it out ever so slightly, you could use it either way. So I had to live with mine having the needle set to the right side of the engine.

As usual, my engine was a bear to start. Then it started to easily flood. I had 'popping' almost instantaneously as I had set the needle at 4 turns (was kinda thinking of this as a starting point). Without any luck, I had thought I recalled a needle having to be open at 6 turns, so that is where I went to next. The 'popping' was actually better at this setting. But still no go. I then shut the needle completely and ran off all my excess fuel. Re-opened the needle to 3 1/2 turns and hook up the glowhead. It took off for a couple of seconds then stopped. I adjusted my tank height a bit higher and tried again. It again, fired right up. I then leaned out the needle slowly and listening. After it did not get any higher pitched, I backed the needle back out a couple of clicks for engine safety. When all was said and done, my final needle setting was set at 2 3/4 turns open overall. As well, my test RPM's were not taken as I do not have a tachometer and was all done by ear (wearing ear-muffs). Both tanks were about equal in respect of difference in needle settings. Needle settings were observed by marking the end of the needle using a Sharpie permanent marker. I cannot really think of anything else at this very moment, but if anyone has any questions in regards of my testing, I would be glad to try and help out to the best of my abilities.

Last thing to note is that I am a relative 'newbie' when it comes to running TD engines. I have only run TD a few times before this so there is probably some inexperience into setting up and starting these types of engines. Also this is my first real review of something, so if there was something I missed that you wanted to know please let me know. I had a lot of fun doing this and hope my results were what you were looking for.

NEW222 wrote:Ok. So made a bit of time today to do some running in. Here are th estats as of the time of running the engine.
Temperature:
73.9°F
Dew point:
59.4°F
Humidity:
60%
Humidex:
81

Location is approximately 803 feet above sea level

Items used:
Really well run in and abused TD .051
Cox 5 x 3 Black propeller w/o safety tips
1 head gasket
TD glowhead
20% Sidewinder fuel with added castor
Homemade hotel shampoo bottle clunk tank
Balloon Tank

First, the installation of the new parts. All went well and smoothly except for one thing. The fitting of the venturi into its hole in the spraybar. On my test piece, the venturi only went in one way completely. If I put it in the other way, it would not completely seat itself and not be able to needle at all. I think if one was to drill it out ever so slightly, you could use it either way. So I had to live with mine having the needle set to the right side of the engine.

As usual, my engine was a bear to start. Then it started to easily flood. I had 'popping' almost instantaneously as I had set the needle at 4 turns (was kinda thinking of this as a starting point). Without any luck, I had thought I recalled a needle having to be open at 6 turns, so that is where I went to next. The 'popping' was actually better at this setting. But still no go. I then shut the needle completely and ran off all my excess fuel. Re-opened the needle to 3 1/2 turns and hook up the glowhead. It took off for a couple of seconds then stopped. I adjusted my tank height a bit higher and tried again. It again, fired right up. I then leaned out the needle slowly and listening. After it did not get any higher pitched, I backed the needle back out a couple of clicks for engine safety. When all was said and done, my final needle setting was set at 2 3/4 turns open overall. As well, my test RPM's were not taken as I do not have a tachometer and was all done by ear (wearing ear-muffs). Both tanks were about equal in respect of difference in needle settings. Needle settings were observed by marking the end of the needle using a Sharpie permanent marker. I cannot really think of anything else at this very moment, but if anyone has any questions in regards of my testing, I would be glad to try and help out to the best of my abilities.

Last thing to note is that I am a relative 'newbie' when it comes to running TD engines. I have only run TD a few times before this so there is probably some inexperience into setting up and starting these types of engines. Also this is my first real review of something, so if there was something I missed that you wanted to know please let me know. I had a lot of fun doing this and hope my results were what you were looking for.

Thanks for much for the detailed review!

We are getting closer on these and hope to have a "final" version ready in a week or two.

EXModelEngines wrote:

Thanks for much for the detailed review!

We are getting closer on these and hope to have a "final" version ready in a week or two.

Excellent Mr. Matt!

Good Test Review New222 !! It sounds like you had some Fun doing the engine runs