Wasted power!

[Jamin_00]

Bringing up an old thread but did anyone ever do this and find out???

[sacko]

I thought about it, but didnt want to risk it just in case..

[Rctintin]

I just seen this morning FL have YS headers in for £10 odd, so am very happy to give mine a go. Trouble is, my flying is not high enough standard to see the difference. So if there is anyone out there who is willing to push their YS with my modded header, and tell all, I'm only to happy to mod mine. Someone on helifreaks swears by it. I was searching around after I got mine and had seen the difference in port size.

[0h5h1t]

noticed this a while back on my heli's and having a two-stroke tuning background promptly dremeled away the excess to give the exhaust gasses a smoother exit from the engine.. power did increase in all cases too.... just never thought to post it.. Nice one Rob

[Rctintin]

Come on then guys, who is a stick banger with a YS to give my header a try?

[jamiem]

ive got a std header on at the mo

[Rctintin]

Jamie, i've just ordered a spare one from FL, so do you fancy being a guinea pig, and seeing how much 'extra' power you have?

[jamiem]

more than happy to give it a go

[Rctintin]

Ok, I'll wait till I have the one from FL to make sure it's the same, and flow one of them and send it down to you mate. Thanks Jamie

Watch this space!

[jamiem]

I also have a kasama header, but its seen better days since i had to slot the head of a bolt. Still useable, so could do a few back-to-back's.

[moyesboy]

10 or more years ago averyone had full tuned pipes on their helis.
Why not anymore?
Full tuned pipes work over a very narrow rpm range.
however with todays governers, so do our engines.
Maybe a setup with a full length double cone and silencer tuned pipe might work well with a modern engine and governor.

[ddracer]

As you can see from my avitar I'm also a racer. I started of at 15 on two strokes then moved to a GS750 in the earlystocks. Went through supersport 600 to powerbikes. One of the best book I every brought was Tuning for speed by Phil Irvine. If you want to know anything about tuning strokers or building tuned pipes this book is a must.

My combat wunder is running a ASP46 with a tuned pipe and I spent a long time porting the engine and matching the exhaust. The inlets are P60 to aid the mixing the crankcase is corked and the exhaust port is polished.

This is my point the engine runs like a bag of S**T at anything below 3/4 throttle but above that it spins a 10x9 prop at 18.5 rpm. This is great in the plane as I only use it for speed runs but i doubt it would be of any use at all in a heli.

Its all very well getting loads of power out of an engine but that power has to be usable and I think that is where a lot of the seemly mismatch and "bad engineering" on these stock engines comes from.

One more note the more you tune an engine the shorter its life span, below is a pic of one of the 46's pistons after pre-ignition crowned the piston. Would you want this on a heli expensive heli engine after about 30 mins of running.

[moyesboy]

As I understood it, the tuned pipe assiss the motor at the particular rpm it is has the tuned length for.
with a conventional fixed wind set up the length is tuned to be right for the rpm that the motor has at full speed and full throttle becuase you are looking to go at the maximum speed possible.

however if you are running 2100 head speed and 17000 rpm on your trex600, and you fit a tuned pipe designed to peak at 16500 then the motor will be on the pipe at half throttle and zero pitch, and hopefully still on the pipe at full pitch and full climb.
Obviously if you bog the heli then the consequences might be quite disadteous with a huge loss in power and a slow recovery - but maybe the extra power might make that less likely?

With a governor aiming for the set rpm when you spin up at zero pitch it will do whatever is necessary with the throttle to get through the lumpy bottom end rpms and onto the pipe at the intended head speed, when it should come on the pipe and then throttle back ansd stay on the target rpm nce and happy?

I'm told the old 3D helis running tuned pipes benefitted from the pipe giving them a governor effect - when they tried to overspeed the pipe went off tune...
however with a governor and a peaky tuned pipe the non-linear and rpm dependent throttle response can lead to stability problems for the governor.

[J-S-Q]

What exactly is the difference between a 'tuned pipe' and the sort of mufflers that are generally used today (or are they still 'tuned pipes'??). Many years ago I had a Kyosho Nexus running a Weston Gensis tuned pipe like this:

50 size pro pipe l/h

Unfortunately I never progressed far enough with flying at the time to assess how good it was but it did at least allow the MDS engine to run consistently compared to the stock pipe which gave me endless trouble and it certainly sounded a lot nicer/quieter. I have been wondering why you no longer see thus type of pipe (particularly as it says it suited to an OS 50 Hyper). Has anyone ever used one?

[moyesboy]

I've seen a long pipe similar to this on a millenium at our club.
You also see them on blinged up raptor .30s coming up on ebay and bmfa.

The pipes common now are designed to have a less pronounced power peak and provide a smoother wide power band (pluse they are smaller and lighter).
...but my point is that we are running our 3D helis at one constant rpm (set by the governor) so an optimised classic tuned pipe might actually work well!

One point against such a long pipe is a typical tail in the deck crash, or boomstrike, might cost you the £80+ tuned pipe as well as all the usual parts