rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 847 ONLINE 20 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]852 viewsPOST REPLY
Advantage Hobby . Revolution Models . CarbonXtreme

.
.
Miniature Aircraft Nitro/Gas Helicopters > Stratus 4 stroke
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

Saito 125 4 stroke in xcell Stratus, gear ratio 6.92:1
High torque compensates to a certain extent for lower headspeed.
Much better performance than gasser.
Still trying to find lower gearing as power is more than ample to aim for higher headspeed, however as is it's awesome
I will increase pitch to see if I can get the motor to notice it's swinging 720 blades!
03-13-2008 04:38 PM
 
 
Eyefly
Veteran
Location: Charlotte, NC

Very interesting. I am going to have to require photos and vodeo for this thread.
03-13-2008 04:58 PM
 
 
kcordell
Veteran
Location: O Fallon, MO

Are you running a governor? You really need one with the four strokes (I ran the YS 91's in the mid 90's for contests). You don't want to overspeed the head (resulting in a serious overspeed of the motor) on maneauvers or you will be replacing lifters and valves at a regular rate. I agree, I really did like the torque factor. It also made a great drag race macnine. Sounded really cool too. I was running a tuned pipe also.

Team Futaba, Miniature Aircraft Pilot, YS Engines, VelTye
03-14-2008 12:33 PM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

I just fitted the multigov and set speed to max 1600, I tached it at 1800 before and was surprised as it should not go much higher than 1650, therefore agree with you that gov is neccessary. Haven't had time to see how it goes yet but expect it to go well.
So far we are all a bit surprised by the performance, seems you can do anything with it without getting the motor to bog down.
I am still looking to lower gearing further as motor seems to be able to handle the pitch rates +_11 very well.

What type of contests did you participate in? Initially I also wanted to build one with the ys, but it's not available so had to go the saito route. Did you have engine trouble due to overspeeding?
03-15-2008 01:56 PM
 
 
FOX222
Senior Heliman
Location: Atlanta, Ga. (Actually Woodstock)

I would love to see some pictures. I also had a Graphite 60 with a YS91 years ago.
03-15-2008 02:36 PM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

Here's one showing motor,as you can see, it's a close fit

03-15-2008 03:17 PM
 
 
kcordell
Veteran
Location: O Fallon, MO

I was flying FAI F3C in the US with mine. No problems with the motor overspeeding due to the governor. You will probably see a swing of 100rpm or so with it, especially when you unload the disk.

Team Futaba, Miniature Aircraft Pilot, YS Engines, VelTye
03-15-2008 05:04 PM
 
 
jake26
Senior Heliman
Location: central cali

pretty cool i bet that throttle linkage was a pain in the a$$

fly it like u stole it
03-15-2008 08:04 PM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

Yep one of them!,but all worth it, flew it today with governer and it's just getting better and better, performance is much higher than anticipated, in fact my friends say it will kick my titan 50's butt!
I'm just surprised with the coversion being so nice to fly and can seriously recommend it to anyone being addicted to 4 strokes.
I set it up with 1600 max but finds 1500 in idle 1 to be sufficient for all acrobatics, going 3d may require the higher limit but I'm not there yet, thing is the high torque factor seems to provide quicker spool up of the blades. I may go lower on gear ratio but not for higher headspeed, only to spare motor in the long run.
03-16-2008 02:32 PM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

Interesting, What kind of headspeed did you run it at? I find it surprisingly fast and agile at 1600 don't know why I would want to go higher. Also did you have an airfilter fitted.
As for the tuned pipe, is it noisier, a good pipe may help with the cooling a bit.
03-16-2008 02:38 PM
 
 
Tyler
Key Veteran
Location: Chicagoland area

Video

We need video with good sound, no music!!!

More pics would be wonderful as well.

As I recall, the problem with fourstrokes in helis was keeping them cool. The carbsmart might be a great addition to this project, especially since this is a single needle carb. One more idea can be taken from the new Compass Models Odin 90. They are using a brushless ducted fan unit and esc to keep the engine cooled. They don't even have a fan/shroud on this helicopter. All the cooling is supplied by the small brushless motor. Perhaps it would be a good backup measure to have a fan added to your already successful fan shroud arrangement.

Tyler

Airtronics, YS Power, Switchglo ignitors, Jersey Modeler filled with Magnum
03-16-2008 02:58 PM
 
 
kcordell
Veteran
Location: O Fallon, MO

The YS91 heli engine had a spacer on the carb that helped with keeping the fuel cooler during transition. This piece was not on the airplane YS motors. Other than that, I never really had any fuel issues. Only problem was if you flipped into idle up from hover and jammed the throttle/collective, it would bog way done and sometimes flame out. Just had to learn to let it spool up after switching flight modes before hitting it hard.

Team Futaba, Miniature Aircraft Pilot, YS Engines, VelTye
03-16-2008 03:20 PM
 
 
lloyd
Key Veteran
Location: Port Elizabeth,South Africa

Well we will have to get vids and pics up and by the way grand heli SAVE today.............

lloyd

future of nitro is ELECTRIC
03-16-2008 06:58 PM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

Hey lloyd, good to see you joined the discussion, now we just have to give your electric some 4 str sound!
03-18-2008 06:15 AM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

Interesting that Tyler mentioned the electric fan, exactly what I had in mind, already bough the fan unit!
Nonetheless although the motor runs hotter than 2 stroke as of yet I did not experience any sign from the motor that it's unhappy at the running temp. I am running it a little richer than optimum.However extra cooling can only benefit.
I also like the idea of the spacer although the use of the header tank may also help a little by increasing flow passage. I have also created a cooling passage between the exhaust and tank to get the exhaust gasses cooler.
Read the report on the carbsmart just concerned that 4 str may run higher temp than max setting (i think 130 c) I know for sure my plane engines run way higher temps than titan 50, will take some readings.
Alas thanks for all the positive feedback and ideas.

I'll work on some video and more pics, also hate the "sound of music"
03-18-2008 06:35 AM
 
 
Four Stroker
Veteran
Location: Atlanta

If this thing holds up, my recommendation is to put a Hatori 821 muffler and hack the corresponding 822 header to fit.

http://www.hatori-models.co.jp/

http://www.centralhobbies.com/Exhaust/hatheadr.html

http://www.centralhobbies.com/Exhaust/hatori.html

Also make sure you are using the heavy duty clutch dampers.
03-18-2008 05:02 PM
 
 
Stolla
Senior Heliman
Location: Port elizabeth South Africa

What are the benefits of a pipe except for the obvious performance increase, as is I do not want to increase performance for the existing gear ratio.
03-18-2008 05:42 PM
 
 
Tyler
Key Veteran
Location: Chicagoland area

Tuned pipe

Back in the kyosho Legato (spelling glitch) days the tuned pipe and header created a whole lot of hassle. The headers leaked, broke, came loose, rattled, caused rf noise. I wouldn't touch that option with a 10 foot pole. Additionally, you risk changing the c.g. of the model drastically and they have little crash or rough auto survivability due to the ways they are mounted.

I like the stock muffler just fine. It is small, light weight, simple, and sound great.



Cooling fan:

If you decide to run the cooling fan, be sure you use a seperate battery just for the fan. Servos and gyros can draw enough current that it will change the rpm of the fan during flight when hard stick movements are made, especially collective. This results in an irregular flow of cooling air.

Tyler

Airtronics, YS Power, Switchglo ignitors, Jersey Modeler filled with Magnum
03-18-2008 06:04 PM
 
 
Dr.Ben
Elite Veteran
Location: Richmond, VA, USA

Yeah, the Hatori heli 4C pipes never used a flex coupler......for good reason.

Can't wait to see and hear the video. More than two minutes, too, please <g>.
03-18-2008 06:56 PM
 
 
Four Stroker
Veteran
Location: Atlanta

I have trashed a dozen flex headers myself. That's why my first suggestion was to hack the Hatori #822 RIGID header. If you can weld/braze two pipes together, it should not be a problem.

The flex headers on the Kyosho, Kalt, and Vario all fall apart especially if you do not rigidly support the end opposite the engine.
03-18-2008 07:18 PM
 
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]852 viewsPOST REPLY
Midland Helicopters . HeliProz . ZoomsHobbies

.
.
Miniature Aircraft Nitro/Gas Helicopters > Stratus 4 stroke
 PRINT TOPIC Advertisers 

Subscribe to This Topic

Wednesday, December 3 - 2:59 am - Copyright © 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie