OS GT 15 ?

[Zbawer]

I'm starting to think my next project could be converting my Srimok 90N to gas engine.
This new OS GT 15 looks quite promising and would be a straight fit, just maybe some slight mod to the fan shroud...
I know the 2.8 HP isn't going to get me into any hard 3D stuff, but if I can sport fly / big air aerobatics for 45 min on one tank I'd be thrilled!
Thing is, Mr. Kasama should try to come out with a solution for increasing (or is it reducing? Can never remember ) the gear ratio, maybe like a 13 teeth pinion would do the trick.
I'm still hesitating, do you agree that could be a good idea?

[thefrog]

Why do you want a different ratio? Does the gasser rev lower?
I couldn't imagine a 13T pinion, would be bog central don't you think?

[BenScoobert]

I've been thinking similar, but i might shrink her to a 600 with dune parts

[Zbawer]

Hey Ben,
You know what? That's actually a brilliant idea you got there!
I guess stock 90 rotor head (LRH with comp arm) can still be used, fitting 600mm blades would only require to pull out the metal sleeve inside the blade root hole so the M5 screw can go thru...
Only need to shorten the boom using dune parts... nice!

Yeah frog, the OS GT 15 revs slower, max power is 2.8 at 14K, so defo need to find a way to increaase GR
BTW nice pictures of yours on kasama homepage

[BenScoobert]

Originally Posted by Zbawer

Hey Ben,
You know what? That's actually a brilliant idea you got there!
I guess stock 90 rotor head (LRH with comp arm) can still be used, fitting 600mm blades would only require to pull out the metal sleeve inside the blade root hole so the M5 screw can go thru...
Only need to shorten the boom using dune parts... nice!

Yeah frog, the OS GT 15 revs slower, max power is 2.8 at 14K, so defo need to find a way to increaase GR
BTW nice pictures of yours on kasama homepage

I was considering doing a swap around on the 90N and the dune to make a 700 Dune and 600 Srimok gasser.
Not sure if it would work but I'll enjoy the tinkering.
I don't run balls out 3D so a reduced headspeed on Dune with 700 blades should be OK.

[thefrog]

Originally Posted by Zbawer

Yeah frog, the OS GT 15 revs slower, max power is 2.8 at 14K, so defo need to find a way to increaase GR
BTW nice pictures of yours on kasama homepage

I guess you could use the 98T main gear, but that hardly makes any difference - I've tested the 98, 99 and 100 and found the the difference to be marginal - maybe 200 rpm either direction. They give 8.17, 8.25 and 8.33 ratios. the 13T will give a 7.62, so about 1840 rpm.

Big thanks for the heads up on the photos! I'll feel famous for 5 minutes.

[Zbawer]

A 700 Dune?
What advantage would you get compared to the FAIFA?
You might wanna check the Dune' servo layout is still going to give you enough throw for the 90 size rotor head, and vice versa not waist servo resolution on your 90N running Dune' s rotorhead.
This is because the Dune' s rotorhead doesn't use mixing arms on the grip, if you see what I mean.

But back to this Srimok 600 with OS gas engine, that would be awesome ! But still need to sort out the GR with 13T, maybe 14T, pinion ; Is it something that can be tailor made? Who shall I ask?

[BenScoobert]

Originally Posted by Zbawer

A 700 Dune?
What advantage would you get compared to the FAIFA?
You might wanna check the Dune' servo layout is still going to give you enough throw for the 90 size rotor head, and vice versa not waist servo resolution on your 90N running Dune' s rotorhead.
This is because the Dune' s rotorhead doesn't use mixing arms on the grip, if you see what I mean.

But back to this Srimok 600 with OS gas engine, that would be awesome ! But still need to sort out the GR with 13T, maybe 14T, pinion ; Is it something that can be tailor made? Who shall I ask?

Not much really, lighter I suppose, I was just thinking if I made a 600 Srimok I'd have a 700 boom and boomless Dune :-D

[thefrog]

Originally Posted by Zbawer

But back to this Srimok 600 with OS gas engine, that would be awesome ! But still need to sort out the GR with 13T, maybe 14T, pinion ; Is it something that can be tailor made? Who shall I ask?

I'd suggest asking Kasama for the pinion first. They did make a 13T a while back - I recall Gavin testing an Eco with a 13T pinion, running 2050 rpm on the head. I'm not sure if it was a limited production run on that size as I haven't seen them on sale elsewhere.