ftjets

I have been building/flying helis on and off for 20 years. I'm back on again with a Raptor 90 and can't decide which engine to put in it. Anyone tried the thunder tiger 91H? I will be retraining my thumbs for a few weeks and then easy flying until i get back in the habit so i don't need a supercharged powerhouse for now. I prefer O.S. but at twice the price, i figure the TT should do the job and wear it out while i am re-learning. I still have a TT .46 Pro that ran great so i am familiar with the quality. Any advice?

BarracudaHockey

My Feedback: (11)

I'd personally get the YS, once you get it broken in its set and forget.

Maybe Ed (FLYBOY) will chime in, he had some engine tribulations with a Raptor and different 90 size engines.

Rafael23cc

My Feedback: (6)

How much learning time you think you need that you are going to...
?

I know is not the same engine, but I was purposely leaning my TT36 to try to kill it and at the same time extract maximum power, to be able to purchase a better engine. Let me tell you that the helicopter flew away before I noticed any kind of power loss due to wear.

Read how my engine (and whole helicopter) died:
[link]http://runryder.com/helicopter/t142562p1/[/link]

So my question is why buy twice?

Rafael

ftjets

Thanks for the replies. I have seen several posts concerning OS and TT heli engines and have seen negative issues with both. I have not seen any posts on the YS. I don't mind paying for quality but being out of the loop for awhile, as in a ten year, 700+ jump skydiving addiction, ("Keep your eyes on the sky but your feet on the ground", sorry Rafael) i lack the knowledge i once had as far as equipment. So much has changed. I did acquire a Raptor 60 about four years ago but had no time and no place to keep it when we opened a small business and confiscated my workshop so it was sold after about a year. I did put an OS in it but i wasn't overly impressed with the power. Probably from improper set up or tuning i guess. Also, i think that i may have been either a little confused or overzealous in establishing my profile. It was very early in the morning. Intermediate may have been a wee bit misleading. I can hover without issue and usually pretty solid. I advanced to let's say, successful basic forward flight and maybe a minor trick or two. Bottom line is that i will be hovering again for a few tanks before getting the nerve for real flying. I'm not as young as i used to be either. I do need to make a decision as the kit will arrive within a few days and i will probably be at the engine install phase in about a week or two. The last heli before the Raptor 60 was a Schluter Heli-Star in which i had an ASP 61 airplane engine. Really! It flew great and had plenty of power. That was almost twenty years ago. Anyway, i welcome any other tidbits of advice and appreciate all the help. Thanks.

ftjets

I have made a decision. I have ordered an OS 91SZ-H PH Hyper with pump. Now is there any advice on setting it up?

mxracerx43

Jumping right in head first!! I like it. $$$$ I am wanting a 90 myself but I still crash to often for it to be financially fesable.
I may sell off a brand new V1 30 I have been saving for a scale platform to get some cash and possibly buy a 90 kit to start a slow build on. I do not have any advice on engine selection for you but have you considered a 30 or 50 size heli to get started again? I know it is a little late being you have
the kit already but have you priced the cost of normal crash items for a 90? You can buy all high end electronics for the 50 and then transfer them over to the 90 once you are comfortable flying again. The 50 is alot cheaper to repair.

Neriyah

xviper, some setup tips for your os91.


If you run 30% nitro add the 2 extra shims that come with the engine. If you run 30% CoolPower you should be ok with adding just 1 shim. It's shimmed for 15% so you will get pre ignition with 30%.
Your middle needle factory setting will be way off. IIRC manual says 1.5 turns out, mine is at 1/4 turns out For breakin I'd suggest you go 1 turn out and go in from there till you can actually spin up the heli.

Set up is pretty much the same as 2 needle engines.
First do the high needle, then low needle and lastly middle needle. I actually prefer 3 needle carbs, they are a lot easier to tune than 2 needle ones (IMO that is).

ftjets

I know what you mean mxracer but i didn't intend to understate my abilities either. The longest period completely without a heli was about eight years. Then, I bought the raptor 60, set it up and after five minutes was hovering solid and moving around the yard. It has only been a little less than two years since that one was gone. Of course, i may be on here whining about an expensive rebuild when i get comfortable again and start playing around. Who knows? I'll take it slow and get my thumbs retrained. (yes, i am a thumbs flyer, started that way in 1979 and never looked back) Neriyah, i appreciate the tuning tips. I've read elsewhere about the needles being way off from the factory. Thanks for the help.

mxracerx43

Oh yeah not trying to put down your abality's or learning curve. In fact the 90 should be super stable and even easier to get
reaquainted. But we all know sooner or later we all crash. I am at the point of getting into mild 3-d and I am not trying to advance to fast but I still crash to often I think to plunk down for the 90. My last crash I was doing some inverted backwards and just lost orientation flying away from me, it cost me enough the way it was and probably would be double that if it where a 90.

ftjets

I know what you mean mxracer. First of all, recall that i have been flying since 1979. While i won't reveal my true age, you get the idea. I started flying helis in 1987 with a Kalt Baron 30 if i can recall. (was there such an animal?) It was small but that was a long time ago. I even have videos of flying that one. Since then, you know the old wives tales, vision goes, confusion etc. The Raptor 90 is big so i can see it and should be quite stable. There is no doubt that after a few episodes of hovering and figure eights, the urge to go for it will finally arrive and then we will see what posts i will offer. Back in 87, i had the priveledge of knowing several accomplished heli pilots that helped me learn. I am the founding member of an AMA sanctioned club in the northeast and at that time, everyone was facinated with helis. I could get away with just hovering and be a rock star. Now adays, i watch the you tube videos and am horrified thinking about even trying some of the maneuvers. While it may have been around at the time i flew my Raptor 60, 3d still meant the goofy looking glasses at the movie theater to me. I have taught several fixed wing pilots to fly and always made them completely aware that they WILL CRASH! I am sure that i will visit the local hobby shop for replacement parts at some point. I have just gotten good at making it look like they are just spare parts in case some wear out. In any case, this forum seems to be a great place to talk and BS a little about helis and i appreciate all the help and advise from those of you who take the time to respond. Happy flying!

mxracerx43

Not trying to make anyone feel "old" but, I was born in 1979. I have seen pictures of those kalt Barons and from what I have heard
about old helis if you flew one of those animals back then, you should have absolutely no problem with a new Rappy 90.

soop7667

Glad to see you digging for the info xviper. I remember meeting you in the hobby shop...and I take it you really decided to go all out instead of the T-Rex 450 you were looking at. When you're ready, come and see us at the field...Cape Bob has a couple of the Raptor 90's and he's run both YS and OS in them I beleive. It'll be fun to have you out flying with us once you get it all set up. Most of our little Heli Flying group from the field post a lot on http://www.rchelispot.com

ftjets

Hey soop,
I thougt that was you in the picture. I found the hatiri pipe at helihobby.com. Yeah, when i saw the tiny canopy on the trex, i knew that i wouldn't be happy with it. I need something big at my age so i can see it. I thought about the 50 size electric but with a $300.00 battery figured i might as well stick with what i know and polute the atmosphere a little more. All this new electric stuff is confusing. I guess i'll probably hold out for a few more years with the "I love the smell of nitro in the morning" crowd. The kit should be here this week so i will look forward to joining you guys in a couple weeks. I also have to figure out my new futaba 7CHP which i'm sure will be a blast. For you mxracer, in 1979 (the year my daughter was born) i was serving in a Marine Corps special operations unit called 1st Recon Bn. and had a 27 inch waist. It really does suck getting old. Poor vision, a little alzeimers now and then, throw in some arthritis = big loud heli.[sm=tired.gif]

mgarciah

My first 90SE cames with the TT.91, is a good engine but i got it because it came as a kit, If I need to buy one engine it will not be my choice, this engine runs well, but it has several air leaks which avoids you to set it up correctly, in fact, is extremely hard to stop it even with the carburator air intake is totally closed. due these leaks is hard to get the right mixture, the engine will hold and work, now Im using this engine in my 90 Agusta, just for scale flight, you know, hovers, forward flight and land, I bought the OS Hyper with Pump for the 90SE.

invertmast

My Feedback: (23)

Just for those who might read this in the future..

I've got a YS91SR in my avant FX. This engine is probly the best heli engine i've ever owned.. I set the needleds per the manual, filled up with some 30% coolpower and it fired right up the first time. I haven't touched the needles since i finished getting it broken in and tuned correctly.. that was 3 gallons ago.

The only downside (which i've had with other engines also) is if you dont disconnect the pressure line immediately after shut down, or use the fuel shutoff clip, it'll push just enough fuel to hydrolock the engine on the next start. other than that, i love my YS and will probly never go back to an OS heli engine again..

archiebald

With my YS50ST, I just close the fuel line to the engine and let it stop, then unplug the pressure line. Never had a hydrolock problem yet.

soop7667

One of the guys I fly with uses the YS90 and turns his starter shaft by hand to close the exhaust port with the piston when he's done flying. He says if not, he get's hydrolock from excess fuel flowing back into the engine from the muffler.

Rafael23cc

My Feedback: (6)

Why would there be fuel flowing back from the muffler? YS engines do not require muffler pressure to run, there isn't a requrement for a pressure tap. The pressure comes from the pump on the engine. If there is fuel flowing back from the muffler, several things are wrong.

1. plumbing.
2. Faulty one-way valve.
3. probably an overly rich engine, and is oil flowing back, not fuel.

I have an OS 91 SZ-H with a pressure tap on the back plate of the engine. No muffler pressure required, just a one-way valve between the pressure tap and the pressure nipple of the tank. At the end of the flight, the pressure gets released and no fuel flows back anywhere.

Rafael

invertmast

My Feedback: (23)

I can tell you that its not just the fuel that locks mine up, but the oil in the muffler (hatori 19) also plays a roll in it also.. With the power output of the YS91SR i dont have to run it anywhere close to peak temperatures to get the power i need for the 3D flying i'm doing. And i STILL get over 10 minute flight times per tank...

I also dont pinch my fuel lines to shut the engine off every flight b/c i prefer not to starve the engine of the oil its getting. instead i pinch it off until i hear it begin to start rising in rpm's, then pinch the exhaust port off to shut off the engine. then i release the muffler pressure and stand the heli nose up to drain any oil left in the muffler out.

Using this practice everytime i dont get nearly as many hydro-locks that i used to.. but if i dont do this and i have to do a cold start after an hour or so, i'm gauranteed to get one...

archiebald

Pinching off the main fuel line is not going to starve the engine of oil in the few seconds it takes to cut out, especially if it has already been idling for a few seconds. There will be plenty of oil condensed out onto all sliding surfaces that matter.

What it will do is allow as much as possible of the volatile methanol / nitromethane to be burnt off and that is the stuff your want to get out of your engine at the end of the day as it is that which will absorb moisture.

Best reason for turning the engine to close the exhaust port is simply to keep humidity out of the engine, it ain't gonna stop a hydrolock.

invertmast

My Feedback: (23)

yea well, i still feel its un-necessary to starve the engine for fuel after every flight when you'll just be flying it again in a few minutes. end of the day flying, yes i agree with starving it to get rid of the fuel.. And the power the ys has, when u do so it revs up a good bit. i've already had to replace on clutch liner.. dont feel like having to do it again. haha