Are original TeeDee Pistons stronger

My Theory Ron,-

I read somewhere that some bods have found the ball needing to be re/set from the packet.
I always check mine before the first 'fire up' and have found them fine.
As you'll see from my 'numbers' they run fine for a while..
BUT
I think prolonged (ten plus tanks) high speed, high performance use and then
suddenly some just let go.

Up early for work in the Morning so not much time to investigate this at the moment but I've taken the cylinder off and as I suspected the ball/socket is looser the a lady of ill reputes knicker elastic.

IMHO the later-run Estes pistons are not of the same quality as the ones from the 80's. Tolerances were also increased.

I have been in contact with the outfit that made the blanks for Estes but their minimum run is 25,000 lol.

Needless to say Bernie my next order will include a reset tool.

John,

If you need a reset tool PM me your address. I have a Davis Diesel one I no longer use any more. You can have it.

Jason

John Goddard wrote:
Should I just fit the Norvel?

If you want to run at +20000rpm, then the Norvel will do that without any complaints, and keep on doing it for along time. The only problem is that you will not want to go back to cox engines ones you get a taste for the Norvels, they are simply much better in every aspect...

.

Wow, scary !

John Goddard wrote:Were they made any stronger than Bee type?
Are the sure start type not 'all that'?
Am I unlucky?
Am I pushing them too hard?
Should I try a TD?
Should I just fit the Norvel?

Third time it's happened to me all late Estes surestart type pistons.
This is the Dragon Extreme after it's second flight today.

Jason_WI wrote:John,

If you need a reset tool PM me your address. I have a Davis Diesel one I no longer use any more. You can have it.

Jason

That's really Kind Jason
Thanks

John Goddard wrote:Were they made any stronger than Bee type?
Are the sure start type not 'all that'?
Am I unlucky?
Am I pushing them too hard?
Should I try a TD?
Should I just fit the Norvel?

Third time it's happened to me all late Estes surestart type pistons.
This is the Dragon Extreme after it's second flight today.

John,

(I hope I am not teaching my Grandmother how to suck eggs!) (Another British saying!)

This is a classic sign of pre-ignition or "pinking" caused be the engine firing on the upstroke. This is not helped by the more softly annealed metal at the piston crown that, although it allows the ball and socket to be set and reset, weakens the strength of the piston at the "join" where the softer metal meets the more brittle.

The usual causes of this can be one or a combination of the following:-

Compression too high
Too high a nitro content for the compression ratio
Too large a propeller.

A change can also occur post launch as the engine setup has to be suited to flight rather than bench running.

Diesels are easy to adjust and usually, after finding an optimum setting when static, for flight - when the load on the propeller changes in free flow - the compression ratio is taken down a peg before launching.

However, glow engines are more "suck it and see", "trial and error" and adjustments made until the piston stops popping. Much more involved with shimming etc. on a glow! A diesel just needs a simple adjustment - usually a 1/8th turn on the compression screw.

Oddly this one went on a standard Head Ian.

The Killa B'stard may have been, cos it went pop on 60%

The surestarteedee, I can't remember.