TT Redline 53 Tuning help!

[quinnj3]

Hi All,

I have an old new TT Raptor 50 V2 SE With this old new engine in it. Ie both the heli and engine are new as they don’t appear to have flown before. I’m the 2nd owner and have taken an interest in flying this now after getting the sticks on a Hirobo Sceadu. The heli flies fine but the engine is a bear to tune. The engine is in perfect condition with no tarring or scores and great compression. It starts on the button and will idle forever. Once loaded up it will rev strongly too. The problem is the mid point. I can tune for good power and response through the Rev band but it will run lean at the hover point and get hot. I can tune for good smoke and cool temps but as soon as I put load on it the engine dies from too much fuel. Help! Please.

Exhaust is a TT hi flow, fuel is optifuel 12 and glow is r3. Head has standard shim fitted.

[quinnj3]

Well, I might just have cracked it. I fitted a 2nd thinner shim and changed plug to an O.S. no.8 which has a far superior glow to the r3 that was in it. It’s quite windy tonight and I couldn’t pump the collective in my yard but the way the engine throttled up and maintained a steady run with equal smoke throughout the rev range is indicative of a reliable run. I instantly knew on the first power up from the sound and smoke it I’m onto a winner with this base tune. It was getting dark so I left it for the night. I’m confident now it just needs dialled in a little more.
FYI I’m just past the hovering stage so no requirement for the high nitro stuff just yet.

[hedge]

A common misunderstanding is that higher nitro content is the domain of 3D higher power set ups. While this is a side effect, the main effect of higher nitro content is being able to run a much richer engine tune, hence lower temps, more oil - lubrication and a wider tuning band due to the higher power available.

Now I wont try and convince you to change - just educate - thats your prerogative but if you do decide to give it a go I recommend 20% nitro heli fuel. Now again I am assuming your 12 is heli fuel, if not then you should swap straight away. Buggy fuel is not designed for Helis, Nitro Helis fly best at or near wide open throttle "WOT" and the oils in the fuel are designed to manage this position. Buggys are rarely at WOT, they mostly play around mid/low range with the odd spurt of full power down the straight when racing and their oils are designed for this use.

[waveydavey]

TT recommend 30% for the Redline, I ran one well on 20%. I modified one to accept a 3 needle OS carb which improved it no end, the Redline is all or nothing I'm afraid and you're not helping it with the lower oil content as Hedge says

[quinnj3]

I’m running Optifuel 12 helicopter and aeroplane fuel. It is 18% oil content from memory. Definitely not car stuff. I don’t know where you get the recommendation of 30% nitro content for TT engine. The manual in my hand states 10-30% nitromethane so mix I’m using is within design parameters. It does recommend 20% oil though. Whilst I agree running higher nitro content would facilitate a more reliable burn, I think it’s reasonable to expect reliable operation on 12%. From all accounts the carb is rubbish. The O.S mod seems to be popular. I’ll know better on Sunday when I get to the club but so far the engine seems to be running much better. Years ago I run ‘planes on 5% with no issues. To me 12% is high nitro.

[waveydavey]

I remember it being in the manual but maybe I was mistaken, what do I know, have fun.

[Bell47Man]

20%

i now run my engine an OS 50 SXH on 20% in my TT X50 (old but reliable) and have no issues at all. very easy starting and reliable runs. So very happy.

[quinnj3]

Just a quick update. I had the heli out on Saturday for a few flights. I set the mixture for hovering then did a little bit of ff flight. This produced very little smoke so I brought it in and the engine was a little hot as suspected. I turned out the low idle mix and tried again. Perfect. 3 flights later and the engine and helicopter appear to be flying well, at last!