.80 Scale Power :-)

[maderdog_1024]

Hey guys was offered an engine last night with a cut down crank shaft, apparently it had been in an accident of some sort on a plank.

Anyhow, the pictures below do all the talking !

Its an SC .80 4 Stroke and it fits like a glove.

Just working on the gearing and it will be flying my 3 blade jet ranger soon.

Mike

[maderdog_1024]

Okay, as the 4 stroke only revs to about 11,000rpm my head speed is going to suffer slightly.

What options do I have ??

I have just sent an email to Helibug who do the gasser conversions asking about 20T/17T mod1 pinions so i can run the t-rex 700 115T main gear.

Apart from looking at belt drive systems im a little stumped on gear ratios.

Mike

[Si_B]

Might be worth checking some other forums, I've sure I've seen a 4 stroke conversion of a Trex 600.

[pgkevet]

Okay, as the 4 stroke only revs to about 11,000rpm my head speed is going to suffer slightly.

What options do I have ??

I have just sent an email to Helibug who do the gasser conversions asking about 20T/17T mod1 pinions so i can run the t-rex 700 115T main gear.

Apart from looking at belt drive systems im a little stumped on gear ratios.

Mike

That's the right sort of GR but remember that the pinion size is such you'll end up having to move either engine or mainshaft to get the mesh..and if you move mainshaft then the tail gear problems happen....

[Steve]

A chap at our club had a 30 size heli once with an OS52 4 stroke in it. The engine tended to get very hot, needed regular tappet adjustments and would burn out the exhaust valve with ease.

As for flying, it was even more under-powered than the same heli with an OS32 heli engine, so presented some interesting flying characteristics, but it did none-the-less fly and made a nice noise.

[maderdog_1024]

From what I can see on the forums and other conversions people seem to only use stock gearing ?!

One guy seems to think that a his 4 stroke revs to 15,000 !

ASP .80 4S = 1.56BHP@ 11,000RPM
ASP .53 2S = 1.89BHP@ 17,500RPM

I cant seem to find Torque figures for these engines though. So I dont have much to go go against so far.

If im struggling for power, im told the .91 is the same size. So we shall see.

Mike

[maderdog_1024]

Found some interesting videos;
[ame=http://www.youtube.com/watch?v=R1rkIXjZaus]YouTube - Pantera 4 Stroke Magnum 91[/ame]

[ame=http://www.youtube.com/watch?v=QXssjSMUs_8&feature=related]YouTube - Pantera 4 Stroke Vid 2[/ame]

[ali_Helibug]

with Saito 20cc....

2 years ago, I made the design for using Saito 20cc on trex...and discontinued the product research due to massive heat issues with this engine....there was a tremandous amount of time spent on design and testing....but, unless you have some reall good cooling system to cool the 4-stroke down, i wont recommend going that route....
just my 2 cents.