Running in a Tee Dee with 0% nitro. Wowzer, I found the right combo and it sings a beautiful song now!

Truth be told, there isn't a fuel hot enough for the TD to handle. In other words feeding a TD 50%-60% nitro isn't going to do it any harm. If your trying to make a runner, the ideal situation is to heat cycle. In the event that you go easy on the engine initially, the problem occurs when you decide to push it. The material hasn't heat cycled thoroughly enough to withstand the added heat and the piston swells causing galling. Rich Lopez in the 80's wrote an article in addition to the Lil Matador on how to successfully run your TD. On a trimmed down prop, they were shooting for a distinct rpm number which fails my memory currently. The suggestion was to let cool and do a bit of lapping just shy of the top of the landing relieving the bottom fit in the bore and running again full tilt. Always and constantly looking for a shiny piston and not a dull one which is the result of galling. They would place a bit of rottenstone into the exhaust port by dabbing it with a Q-tip and run it flat out. This certainly isn't for the novice and could do more harm then good if overdone. The point being is that running the TD on high nitro will probably due more good than bad. Running higher nitro is going to make the engine run cooler anyhow. I don't feel that running an engine on 4oz of fuel is going to mate the surfaces and especially if you ran it all at one time. Many of the fits can be successfully mated and polished prior to even running. The problem is relieving the stresses of the metals which is and only accomplished by running the engine. Ken

I really need to figure out how to get a copy of this article from a PDF onto the forum. I'm not much of a computer guru. I know the basics, maybe I could send it to someone and they would know how to post it. Dave, I don't consider it pushing the rpm's. The TD was used as a standard in combat through the 80's until the late 90's when the Shuriken came onto the scene. The Shuriken set a new high in technology but the cost factor which at the time was around $225 really allowed a limited few to use it. The more modern engines started making a appearance and the TD certainly started to become obsolete. I truly believe that the free flight guys push the engines harder than anyone. It's just that it was being done for shorter engine runs. The freeflight crew go for flatout performance. That side of the hobby also desires lightweight high powered engines. Those fellows really deserve a lot of credit for the TD and extracting the power from them. The whole idea is to run the engines in or above the max horsepower curve so that when the engine does have a load on it in the maneuvers or towing a streamer it settles into it's maximum torque curve. The TD has no problem staying together in the 24+k range. When you start heading above that is when certain parts, the crank, the crank pin start failing. I own a lot of TD's and some are strictly dedicated to my combat flying due to the fact they do turn up far greater than some others.

I had a thin wall cylinder for instance that for years was more or less an engine that ran so so. It was consistent and I just never got the power from it I thought it should have. After discovering articles like stated above and also sharing a few e-mails with Paul Gibeault, I have some real runners. Basically, it all boils down to fit. I lap many of my engines in using different polishes and grits. This process really relieves any binds and provides little resistance to the piston and bore which allows for these higher rpm's. I really wish I knew back then what I know now as I got rid of plenty of engines that probably just needed a little tweaking to make them terrific runners. Unfortunately, for those who try it also means your going to ruin pistons, cases in the process. It becomes a learning curve and practicing on parts engines is suggested. I personally found that engine break in time was really cut down and engine rpm's really increased due to better fits. These fits however didn't necessarily mean that the engine had tons of compression as I was in search of a slight pinch at top dead center.

Please don't get the impression that I like to ruin engines by just running them until things blow. I'm not going to say that hasn't happened. I have and this has been the situation using TD's on 1/2A speed stuff. Combat and speed pretty much requires all that the engine is going to give. I certainly don't have an endless supply of parts but I do keep the things that break on hand.

I've seen some discussions on this forum in regards to some that have an engine that runs well but others that don't seem to turn the same rpm's. I'm very curious to this at times with my own engines and I want all of them to be on the same level or close so I'm always striving for those performance numbers. In the past, the majority would always suggest that running high nitro is going to shorten the life of your engines. So it was taboo and this always made myself stay away from those fuels. Well I have ventured into that area and to my surprise discovered how reliable and cooler the engines run. The main problem is cost, high nitro fuels are expensive and so are plugs but using it in 1/2A makes things much easier on the wallet. Once I achieve the proper deck height on the plugs as I like the 1702, I find them to be quite durable. Taking out a plug a flight however can be quite frustrating and I've had some expensive days. Ken

Rusty, I didn't offer a prop suggestion as I use many and I try and utilize the rpm's to the plane. I generally use no props larger than a 5" on my TD's. I also rarely use a 4 pitch prop, however, I found the APC 4.2 x 4 to work quite well. I also found the 4.5 x 3.5 to work well. It all comes down to experimentation and documenting. One of our senior speed flyers, has a audible tachometer which can tell you the engine rpm's in the air just by pointing it at the plane while it's flying. This is the coolest thing I ever seen. I'm sure tools like this also carry a high price tag. Bob the gentleman I'm mentioning has been involved in speed for almost 60 years now. He keeps detailed records of the changes and the engine increases and decreases. Bob also has shown me how to fine tune certain props using a pitch gauge. Another factor is venturi size, so all this tuning in addition to shimming ultimately has an affect on rpm numbers. I realized that closing down the space for the SPI on my TD really improved rpm numbers. I would've thought just the opposite. All of the above really needs to be recorded to understand what is happening. It does for me get boring at times and changing things one thing at a time is truly necessary. I found that the Kustom Kraftmanship shims that go under the cylinder really has helped my TD's come to life. I also had a few lightened, and balanced cranks for the TD which also benefits in rpm's. Trying different heads like the Nelson Galbreath combo which I see your already using also benefits rpm's.

Seeing that you and I are running bladder, you should try keeping a variety of venturi's drilled out for experimentation. I paint mine different colors so that I know what sizes I'm using. Ken

I do like to fly on a competitive level, but I truly enjoy sport flying. I don't subscribe to the I have to win theory. I like just being present. If I finish dead last, I want to know why the guy who won, finished first. I don't feel that in any way I'm changing things as I'm not altering crank timing and porting, I'm just relieving the fit at the bottom end slightly to allow the engine to be free. I feel there's always a scientific approach to all of this. My fellow flyer Dan who's well known in the stunt circles at the Nats, is also well known in control line in general. He owns so many interesting and unobtainable engines and models in control line. He doesn't consider himself a collector and uses everything he owns. This includes about a dozen post war all aluminum models with period engines which he flies daily. Dan has a knack for running TD's and always has mine beat. He just owns some of the best runners I've ever witnessed.

In addition, I don't consider the TD to be a museum piece. It is and will always be to me an inexpensive engine. The TD though is a viable powerplant that does produce good power and is extremely light. I've taken many of them and removed the original TD cylinder and used Sure Starts from Bernie and also the cylinders which have the pistons lightened. The original TD cylinders and pistons are just becoming increasingly difficult to locate. I've run the Sure Starts extremely hard with no adverse affect. Afterall, the price of the cylinders are priced for experimentation. Initially, the ball socket was loose even prior to run in, but after 2 resets, all has been good. I've seen some impressive results and I certainly would like to try one with the exhaust slots removed to see if I even see higher rpm results. I've never been a fan of the steel crank running in a unbushed case. I just rebushed one of my Stels engines this past weekend that had worn out extremely bad. I was thinking of putting a bushing in one of my TD cases that has seen some time. When I hold the prop and wiggle it, I can see the piston moving up and down slightly with the crank. I know that this has to have a negative affect on rpm numbers as well. Ken