Update on the OS 120 AX in the H9 Showtime.

Amazing engine, still only have about 6 full tanks through it but very happy. I'm spinning an APC 17x6 prop.


Exhaust report:
I was using a shortened Bisson muffler specifically made for this engine I then chopped down the expansion chamber about 2 inches to make it fit in the cowl, then narrowed the exhaust diameter to replace the lost of back pressure. With this combo I was getting about 8400 RPM far less than the reported 9200. This combo will hover at about 3/8 throttle and has great pull out even at these lower RPM numbers.

I then switched to the stock Powerbox muffler with the pitts adapter and immediately got 8900 RPM. I figure this will improve closer to the 9200 as the engine completes break-in phase. The sound is improved (quieter but deeper), at lower RPM it now doesn't have that irritating 2 stroke rattle/ratatattat sound that it had with the Bisson though full throttle does not sound as impressive. I figure the increase in backpressure will help transition performance (still breaking in) but I'm really excited about the extra 500 instant RPMs. I have not flown this combo yet.

All figures are using 15/15 PowerMaster fuel at sea level.

I may also try the APC 16.5x5W prop and switch to a plastic spinner to reduce weigh and improve transition performance.

Setup question:
The manual states 2 1/2 inches of travel for the rudder on high rates is this correct or a typo?

[sm=bananahead.gif] Maybe I'm naive but why such a huge rudder and only use such a small amout of deflection? [8D]

Do you have any pics you could show of how the fit is with the OS 120? It's good to know the 120 is working great in this plane. I'm interesting in selling another type of plane that I have (still in the box) and getting a Showtime and OS 120. Thanks

Use as much rudder as you can on high rates

I had someone else fly my plane and it does it for them too. I found out if you pull hard vertical it will do it. This is on low rates which is about 55% of the full travel. I also put higher torque servos in the tail so thats not the problem. One question though, how do you measure the incidence at the root because the robart meter isn't big enough? I just measured it as close as it would let me.

Me too.

Robart makes a long bar for that meter; they sell it for about sixteen bucks or so. I keep forgetting to order one; thanks for reminding me... again.

Sounds like it is snapping, sometimes caused by tomuch elevator all at one time.

Thats what it seems like, but it does it on low rate elevator which isn't that much travel.

Hey guys, I'm new to this thread......

I have a Showtime and a Saito 125A in a box waiting for me to get the time....I'll be paging through the thread to see what advice there is for setup.

I hope this plane is as good as people seem to think it is. I am trying to make the transition to giant scale and I have been told that this plane flies like a larger plane...any comments on that from those who are flying the Showtime?

OH....I have a bunch of those JR(sport) MG125 servos. Will they be good enough for this plane?

Nate, You need a starting point, set the plane up at the factory specs. Use the throws recommended in the instruction book.

1600+ posts, wow.

Who has the quick answer for the best rudder servo placement when using a Saito 125?

Gonna start the build tonight!

Mac

The MacDaddy...

With the Saito it will balance easier if you use the pull/pull. The battery will end up somewhere in the forward part of the fuse to balance at the manual specs. It flies good at the manual specs. Get the CG to far back and you're asking for the "Snaps".

Thanks
Barry

I vote pull pull as well

I have the 1.25 and my rudder servo is in the tail. It balanced perfectly, but I do have a Tru Turn spinner. [&:]

I think I will go the pullpull route, haven't done one yet, any tips?

Mac

I've got the 1.25 with the rudder servo mounted in the tail also. I have the battery sitting on top of the landing gear. I couldn't tell you what the CG is though, never checked it, just flew it.

There are 4 other members of my club flying this plane. 2 are flying YS110, 2 use Saito 125 and I have a Saito 100. All of us have the rudder servo in the tail, the only difference is the battery placement. all of the planes fly great.

Are you all using MG servos? I was using MG Hitec 5625's all around except 5645 on the rudder, run on 6V, any comments?

I got all the surfaces hinged and the control horn bolts in last nite, nice, very nice.

Mine does not have the best covering job for a $250 plane, I got mine for Christmas, now they are 199, damm it. When do you ever see the price drop like that?

Also, the wing tube is VERY tight, anyone else see this? what to do?

I see the tail wheel assembly is a part # in the manual, I think I will start buying it for other planes!

Mac

I'm running 5625's and a 5945 on the rudder with 2 cell 2800Mah Li Ion pack w/regulator. The RX pack with regulator weights less than a 5-cell 1650 Nimh and I can fly all weekend on one charge. [8D]

The covering is terrible.. I've been over with the iron and the gun a few times and it looks great until I take it out of the field and it sits in the sun. The pearl purple looks awesome but always lifts and bubbles in the sun. I thought I had encountered horrific flutter on one flight but it turns out it was half of the yellow trim on the botton of the wing peeling away. The red trim just behind the cowl has all lifted off, etc... [:@] I'm really not a fan of Ultracoat now. My last H9 plane had covering issues as well. It just takes a beating in the sun. Monokote holds up MUCH better in the heat and humidity we have in FL.

My wing tube was a little snug but loosened up after several flights (probably not a good thing..).

Overall, the plane flys great. I just wish it help up a little better (don't even get me started on the stab mounting).

The MacDaddy...

I use 5645 on Rudder, 5625 on elevators and 645 on ailerons. I use 4.8 volt. Seems to work fine for me.

My wing tube loosened a bit over time. I'm sure yours will loosen also.

I think your set up sounds fine. Be very careful on your initial flights. Many, including myself have experienced snaping/dead spot with this plane. It flys very nice and I love the airplane. But mine has that curious snap that has never allowed me to fully trust it. Doesn't mean I can't do everything 3D with it. I just do it higher than I normally would because I'm not will to chance "that thing".

Good luck!
Thanks
Barry

Hi all,... I run 5645's for all but the throttle all on 6v's.. I have about 35-40 flts on the S.T. and
so far no bad habits have shown itself, she lifts off and lands smooth as silk... I'm really getting
to love flying her!! after being a bit gun shy of some of the problems, my YS helped alot since
it's now clicking... So I'm in the "Love" mode with the YS:-).... Hope all stays as is
I have no covering issues in this AZ heat, But when first tightening all up I thought it was not
going to shrink, then I thought I was going to burn through it,(iron was not working for me, so I
just use the gun now) but then it shrunk up tight, and I have not touched it since.. My wing tube
seems to be holding up so far... knock on bulsa,,, My stab tube had some play after about 10 flts
but all is doing great after glueing it in...
Another great day this morning.... I'm down to 5' K.E.s and 10-15' hovers... She does them well,
but for some reason I'm still a bit nervous going lower.... But confidence is building..... And she
is starting to be one of the planes I always want to take to the field.... No SFG's yet ...
D_m... Did I just jinks myself[]

Under what conditions do you see this dead spot and snap?

Mac

I am wanting to put a Saito 150 on my showtime... And I am also curious about this snapping. Would a heavier engine cause this? I don't see how that would matter as long as it is balanced.

150 would be over kill. I have a YS 110 and have not had a snaping problem.

I've also been flying the ST for since last year with a YS110 and haven't noticed any dead spot on take off. What a sweet flying plane with the YS110. Since I've been flying the Showtime, my Funtana90 with a YS91 has seen less and less flying time. I decided to give up on the F90 because the Showtime fly's so much better.

Just noticed the CA hinges on the far end of each wing have both broken. Guess I'll replace all the CA hinges on the wing with Robart hinge points.