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TD 049/051 cylinder; double or single booster is better?

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TD 049/051 cylinder; double or single booster is better?

Post  balogh on Mon Feb 08, 2016 3:24 am

The standard, classic No4 and No 5 TeeDee cylinders with stepped wall both have 2 bypass flutes with 2 symmetrically placed boosters at each flute. The double booster opens larger cross section for bypass i.e. less obstructed charge flow to the cylinder, while the latest TD 049/051 cylinders (e.g. sold by Bernie) with thick wall feature double bypass flutes with an asymetrically cut single booster on each side. This design may ensure more obstructed charge floe into the cylinder, yet, the asymetrical booster adds a spin to the charge and the vortex of the charge in the cylinder thus created  enhances combustion efficiency.

In the middle of a 049 reedie build project I am wondering if anyone has tach experience on which design i.e. the double booster stepped wall, or the single booster thick wall cylinder will yield higher rpm? (I read a post somewhere that confirms the second, i.e. asymetrical single booster design will yield higher rpm but I am not sure if this is verified by any tach measurement)

Thank you.
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Re: TD 049/051 cylinder; double or single booster is better?

Post  fredvon4 on Mon Feb 08, 2016 4:14 am

My tach testing on the bench when I was redoing 4 TeeDees did not specifically measure just the cylinder change because I was trying to see if the so called high performance cranks added anything to the game...they do not.... biggest power adder was the tweaking of the Venturi diameter

That said, one of the three engines was a used .051 and one with a used factory TeeDee .049 cly ---and two were with the Bernies .049 "teeDee" version with the slits cut open and new pistons. I did a two fuel cycle run on each engine as a base line for that engine and all were some where in the 21,990~22,850 range

I don't remember the exact RPMs but I do remember both of the Bernies versions were 500~900 rpm faster than my two older used sets and thought at the time that what I read and you just noted was the configuration must add swirl and better fuel delivery or burn

One interesting to me note was the .051 was always down 500+ rpm vs the other three and I was using a Paul Gibeault provided CYL/PC set

All were run with the Galbreath Head and Nelson plug

I did a computer change since then and the data from the testing in buried on one of my backup drives

Would love to own a good small engine dyno to see more about torque and thrust vs RPM

One other note ...while I did use same type and sized props I did not use ONE prop for each test so variances there may have crept into my non scientific testing

Bottom line is-- a lot of words to say I tend to think that Bernie's configuration is a power adder but don't really have empirical testing proof
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Re: TD 049/051 cylinder; double or single booster is better?

Post  balogh on Mon Feb 08, 2016 5:02 am

Thanks Fred this is kinda reassuring that I should go with the thick wall 049 TD for higher rpm no matter if the classic stepped wall looks cooler.

Already have 2 homebuilt reedies with killer bee backplate and thick wall cylinder...one is on my Lil Roughneck whose flight video I have posted in a thread here. Will probably swap cylinders on the newbuild and tach both designs. Will let you know the results.

Thanks again.
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Re: TD 049/051 cylinder; double or single booster is better?

Post  balogh on Mon Feb 08, 2016 6:25 am

fredvon4 wrote:My tach testing on the bench when I was redoing 4 TeeDees did not specifically measure just the cylinder change because I was trying to see if the so called high performance cranks added anything to the game...they do not.... biggest power adder was the tweaking of the Venturi diameter

Fred to what diameter did you widen the TeeDee Venturi? When a high school scooter fun I remember we with my buddies polished the venturi of our 2 stroke scooters and ramped up its power a bit.
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Re: TD 049/051 cylinder; double or single booster is better?

Post  fredvon4 on Mon Feb 08, 2016 8:33 am

I will lookup the final venturi diameter but as I recall it was close to what Rusty had posted and his numbers came from Paul Gibeualt's figures IFIRC

IN fact since the finding of the original data is such a pain, I will just measure one of my 24,000 rpm screamers...stand by

OK the best TeeDee I have has---Texas Timers fine thread NVA....Brenie's cyl/pc set....custom high performance crank....Galbreath head and Nelson plug... two inch small tube bladder fed with Sig 25% with 24~26% castor.....4.75" x 3.75" propeller (green glass from Aero works in Canada) with a venturi diameter of:

inches....0.1175
MM.....2.99
Fraction...1/8th

Note these venturies were just drilled and lightly polished.... no attempt was made to follow normal venturi design with a lead in angle, flat section, and lead out angle



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Re: TD 049/051 cylinder; double or single booster is better?

Post  fredvon4 on Mon Feb 08, 2016 8:40 am

Balogh

I truly think we are able with not much effort to make the TeeDee engines produce more power/RPM than the rod/piston will handle...NO LOAD

I have confidence that my three..( I killed one) TeeDees are performing well beyond their design in the 25,000 rpm range unloaded in the air... the one I snuffed was fed my home brew 45% N and the result was rather spectacular.....grin

These three reamaining start easy and shown no signs of grenading any time soon on the 25%N fuel
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Re: TD 049/051 cylinder; double or single booster is better?

Post  balogh on Mon Feb 08, 2016 8:56 am

Thx I have 3mm drillbits and will take an older venturi to experiment with.
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Re: TD 049/051 cylinder; double or single booster is better?

Post  getback on Mon Feb 08, 2016 9:00 am

Popcorn Popcorn  Fred are you running a lightened piston (maybe you did) /? I don't think I want to go-round any faster but maybe a larger plane>> I blew a TD.049 up at the time didn't know but had a 3 piece piston in it 218?? 4x475 P prop. was were I was but let it bench too long , the Valentine spinner went in to Orbit !! affraid Eric Football Play
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Re: TD 049/051 cylinder; double or single booster is better?

Post  fredvon4 on Mon Feb 08, 2016 9:26 am

Eric I mostly use these on larger wing combat planes and they do try to screw me into the ground but are OK out on 42" lines with no or low wind

I have them on Core House large wing hackers and Jeff Dawson Lite Hawk variants and they are NOT competitive with a real combat motor like a Cyclon, Fora, or even a well tuned .061 Norvel, but they do well for me to practice

I simply was planting too may high priced engines with front bearing in the dirt and the TeeDees don't seem to mind a little nose dirt... They restart easy and me and my son laugh our asses off crashing all the time

I love my Norvel .049s but they are a pain to clean out when you screw them into the dirt

Each of the TeeDees is running a stock piston.... The one time I did as suggested and lightened one....it is a pain to start for some reason so I stopped trying to find that extra 100 rpm that way

I am really zealous about piston rod setting and usually set then up tight and run them in to lossen
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Re: TD 049/051 cylinder; double or single booster is better?

Post  Cribbs74 on Mon Feb 08, 2016 12:26 pm

Guys,

Piston fit and compression are also big players. It's hard to compare two cylinders unless they are exactly the same.

When I was messing with tach race stuff. I used the 4 boost cylinders with good results.

Ron
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Re: TD 049/051 cylinder; double or single booster is better?

Post  RknRusty on Mon Feb 08, 2016 2:53 pm

9/64"(.141") is the size bit I use on my Tee Dee .049 bladder fed venturis. I use a 1/8 bit to test if one has been bored. A stock bore will not pass a 1/8" bit, a bored venturi will.
Rusty

fredvon4 wrote:I will lookup the final venturi diameter but as I recall it was close to what Rusty had posted and his numbers came from Paul Gibeualt's figures  IFIRC

IN fact since the finding of the original data is such a pain, I will just measure one of my 24,000 rpm screamers...stand by

OK the best TeeDee I have has---Texas Timers fine thread NVA....Brenie's cyl/pc set....custom high performance crank....Galbreath head and Nelson plug... two inch small tube bladder fed with Sig 25% with 24~26% castor.....4.75" x 3.75" propeller (green glass from Aero works in Canada) with a venturi diameter of:

inches....0.1175
MM.....2.99
Fraction...1/8th

Note these venturies were just drilled and lightly polished.... no attempt was made to follow normal venturi design with a lead in angle, flat section, and lead out angle




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Re: TD 049/051 cylinder; double or single booster is better?

Post  pkrankow on Tue Feb 09, 2016 1:22 am

Be careful making the venturi bigger. It is better to take it in stages.

The fuel feed will require pressure as soon as it gets bigger than stock. It is a valid argument that TEEDEE's require pressure when stock too.

There will be a point where it becomes much more difficult to hand start. After this it will become impossible to start without an electric starter. Thumbs Down

Good thing it is almost no effort to swap the venturi. Thumbs Up

I have found ease of operation outweighs a couple hundred RPM.

Phil
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Re: TD 049/051 cylinder; double or single booster is better?

Post  balogh on Tue Feb 09, 2016 1:28 am

I could not agree more...increased venturi diameter will reduce fuel draw capabilities...though I have never had any fuel draw issue with TD-s with stock venturi, except, maybe the 010 that is the happiest with the shortest possible fuel line if external tank is used..

Maybe I will start with cosmetics/polishing the venturi internal surface before any surgical operation with a 3mm drillbit.
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Re: TD 049/051 cylinder; double or single booster is better?

Post  getback on Tue Feb 09, 2016 4:53 am

Thanks Fred , sounds like the way to go not to tear up the more expensive engines and still have a blast , the TDs don't seem to mine a little dirt or abuse just clean them off and fire-m back up . What does one of these Jeff Dawson Lite Hawk 's look like if its not too much trouble . Until I get the Bladder thing figured out I will just keep mine stock for now. Sad
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Re: TD 049/051 cylinder; double or single booster is better?

Post  fredvon4 on Tue Feb 09, 2016 6:50 am

Hey Erik

I use "Lite Hawk" euphemistically cuz it makes Jeff nutz!  He calls one of his 1/2a versions  Lil Buzzard

Larry Driskill designed the Lite Hawk and it basically is a foam wing combat plane with arrow shaft boom

Jeff took a lot of different airfoils, and considering the weight of modern ball bearing super .049s and made his own version of a arrow shaft combat plane that is very competitive

Jeff Also has his own design Sonic Chickens that are used a LOT in some 1/2a combat circles..... no arrow shaft...the tail feathers are at the TE and If you try to fly one you better be real good....they are too fast for me

look at this thread

https://www.coxengineforum.com/t3968-combat-flying?highlight=Dawson

In this photo are a few of my foam combat fleet and a Sig Sky Ray for comparison
The orange and yellow is a regular sized CoreHouse Lil Hacker...I have some with larger wings

I takes a real hot TeeDee to fly these out at 42' But close in on 35' they are very flyable.... slap a el cheapo Norvel areo (short nosed) .049 on the nose and they will really go... slap a Cyclon 36,000 RPM screamer on and hold your butt with one hand cuz there are just plain/plane wicked fast ....grin

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