jben

Steve,

Have you flown your GSS yet?

James

SBrian

Not yet! Still snow on the ground here in NH.

jben

Steve,

I haven't been able to work much on mr GSS, but I did finish my Landing gear, except for wheel pants. I used a Hanger 9 CAP 232 gear 25%, but I did have to cut it in the center. Pictures forthcoming. The Fuji 34 is installed on the firewall, now all I have to do is make the cut-outs for the carborator and muffler in the cowl. I will send pictures when finished. I haven't even started with the assembly of the airplane, I like to get the modifications out of the way first. I went out flying yesterday, weather is getting better here.

James

bhorton

My Feedback: (26)

SBrian, thanks for the pics. I don't know why I thought you put a 35GT in the plane. I have been checking the size of the 35GT vs the Moki 180. I think the 35GT is almost 1" wider than the Moki so it would require a large cowl cutout for the muffler. The 35GT weighs 52.8 oz + the muffler so it is about 12oz heavier than the Moki. How did your plane balance? Did it need any weight added to the nose or tail? Please post some rpm figures for the Moki.

jben

As promised, here is the first pictures of how I converted my GSS to fuselage mounted landing gear.

James

SBrian

I'll confirm the size again, but I was sure they were very close in size.

I added about 4oz of weight to the tail to offset the heavier gears on the front and about a 1/4 of an oz the right wing. As far as the motor goes it is turning out to be a Monster. I'm just start to zero in on the settings, Timing, throttle, carb settings... Today I start getting some great results using an Evolution 18x6 prop. Here is what got so far.

Static thrust 18lbs
Idle 1800 to 2100 RPM
Full throttle 12000 to 13000 RPM ? More prop required for future tests. Max RPM is supposed to be 11000. I am to understand that this motor requires about 5 gal of fuel to break in the sun of a gun… Scary!

Most interesting thing is the throttle response. 2000 to 12000 RPM in the blink of an eye well ok two blinks.[X(]


Steve

jben

And some more.

James

SBrian

Nice job! Very professional...

jben

Steve,

Thank you, I see that you are online, I will post pictures of the engine as soon as I make the cutouts in the cowl.

James

fireman7875

My Feedback: (7)

Nice work! You essentially did the same thing that I did except yours is much prettier!

Brian

yyyh412

Well, I heard from someone else that's having the same issues with their GSS + Fuji 32B. The vibration is still bad. went to the MG servo's and at least the gears are holding up (But they are going sloppy fast) and this weekend lost another clevis in flight. My wife says "ground it" till I can find out whats up with this. Since I now have two other folks having the same issues as me. So if anyone else is out there having very bad vibration issues with this combo, please drop me a line.

~johnny

SBrian

John, are you having vibration through the whole power range or just at a specific RPM?

yyyh412

Just a specific range. Its some kind of harmonic resonance in the wings. Mostly on one side. I might try to add a few small sections of material to the fuse saddle and see if that helps.

Tried different props, or no spinner, didn't help

bhorton

My Feedback: (26)

Thanks for the Moki performance report. Very impressive. You may need to go to a 20x6 prop. Be careful not to blow the wings off with that monster engine.

I think the Moki is 60mm (2.4" ) wide and weighs 42 oz. From the 35GT manual it is 84mm (3.3" ) wide without the muffler and weighs 3.3 lbs. (48 oz) without the 5.8 oz ignition. I can't tell by the pics of the engines but they don't look that much different. The Bisson wrap around muffler for the 35GT is 1" wide + a 1/4" thick exhaust flange. So from the center of the motor to the outside of the muffler would be 2.9". The fuse would need to be 6" wide for it to fit inside the cowl. My GSS will be delivered today so I can check on it.

SBrian

Have you tried a motor mount that dampens the vibration? There are some out there for just this problem.

yyyh412

No not yet, Great Planes says its not needed

Its been suggested I slip over the 4-40 push rod a length of silicon tubing. Its really the push rod that has the resonance, and that keeps stressing the clevis

I might try CF push rods and hardware like the big 3D gassers

As a last resort I'll do the motor mount.


~johnny

SBrian

This was download from the link attached.

For optimal soft mounting of the engine in a competition model, nothing beats the mount designed by Merle Hyde, Chip's father. In addition to being a very good mount, it is easy to make by each and everyone, from low-cost parts. The mounts are available from Merle via several suppliers, but the price is high. The cost emerges from the labor, not the materials. I first saw this mount in Chip's Jecyll at world-champ's in Austria 1993, and Merle kindly explained the details in how to make one for myself. Since the 1994 season I have used my own made mounts exclusively, both on YS 4-stroke, OS 'Hanno', Webra 120/145 and OS 140RX, with excellent results in vibration damping. Even though the materials involved are plywood, balsa and rubber tubing glued together with CA, the durability has not been an issue for me. They lasts for more than one season of active flying, and then my needs are fulfilled. A short description of how to make one for yourself can be downloaded here (in Norwegian) : HydeFeste.pdf. To further help those who want to try themselves, I have added some pictures taken during the building process of the one used in my Alliance (2000 season).

http://home.online.no/~ofremmi/HowTo.../HydeMount.htm

Steve

SBrian

John, if I may ask, where is the Clevis failing? If the clevis is under that much stress what about the rest the wing or aircraft? Which wing Left or right from the pilot’s perspective? I have noticed more vibration on the left side of the aircraft then the right. I'm having a hard time keeping the wheel paints on with regard to the left side at idle.

Steve

yyyh412

It's the left side. Both threaded and solder have failed where the ferrule turns to become straight side.

She vibrates 3x as much on the left.

jrf

My Feedback: (551)

That is an indication that something else is loose. Check to make sure that the wing dowel is holding the front of the left wing tight against the wing saddle.

Jim

JR16

ok a few months back I started working on my GSS. I purchased the fugi 32b with the plane. for those of you with this motor how does it run? what 2 stroke oil are you using? I have read that this motor with lack of a better term "sucks", what are you thoughts? this will be my first gas plane.

Thank you
John

yyyh412

I bought the package of the GSS and 32B from Tower, After some vibration issues (My Wing dowl pins were not secured properly by me) I have had no issues with the 32B. It was plug and play. Once broken in, its performance is perfect for my needs (Sport flying) It starts easy, runs well. With the addition of the Fuji smoke muffler and a smoke system it is an awesome site to see.

I'm just using penzoil 40:1 and pump gas after break in. Thought heavy with the magneto ATM ignition, I still had to add 6oz of lead to the tail. The current 32B has no issues as shipped, some crankcases had issues very early on thought.

Does this engine suck? No. Is it the end all for your GSS? No. many engines used produce more power. But as a plug and play unit with the GSS for your average sport flyer its perfect....

~johnny

yyyh412

You were spot on, my dowel pins where loose, after securing them PROPERLY she is no longer a shaky jake!!!!

Thank you
~johnny

JR16

how do you have your electronics setup im still coming up with having to add atleast 12oz's to the plane

Hoghead385

My Feedback: (1)

SBrian, thanks for the advise on the Evo 35. Sorry for the delayed response, been on the move lately. The 35 and motor mount arrived yesterday. I was going to use the Bisson inverted pitts muffler, but I'm not sure it will fit within the cowl. Judging from the tech diagrams, it would be close. Is the stock 14 oz tank enough for this engine or do I need to go larger? I'm off the next three days, looking forward to jumping into this build!