Hobbsy

My Feedback: (102)

The 1.25 is in the new style crankcase with the cam down inside a box, the 1.25 is lighter. As to power, it depends on who you talk to, I've never owned a 1.20.

Hobbsy

My Feedback: (102)

S, be sure the throttle is open as Barry mentioned, check to see if a pushrod came out of its socket, not likely but it has happened.

beaver180

My Feedback: (10)

Hiya Hobbsy,

I notice you have fabricated a velocity stack (?) on your GK there... what are the advantages of this?? I have a 150s and a new 180 myself. The 180 is going into a 1/4 Citabria weighing about 16 pounds or so.

CFN, Paul

Hobbsy

My Feedback: (102)

Hi Paul, the stacks save fuel by keeping the fuel that gets spit out of the carb from just blowing away. They don't add or take away power but do save fuel.

Rudolph Hart

Hi bob don't think anyone has mentioned specific engine mounts and harmonic balance issues??

balsaeater

Yesterday for my Saito 180 I wanted to try out a MA three blade 16*8 intsead of the normal two bladed prop APC 18*6 W or the back up two bladed APC 17*6
I balanced out the prop best as possible but not having a suitable three baled spinner just used the normal nut to hold on prop
i fired up engine and and gunned thing and vibaration was wicked
The self tapping screws which go into the platic engine mount were coming undone
I refixxed the screws and screwed them down tight as possible and tried several times but same thing they were coming undone

I put back on the normal two bladed 18*6 prop and the 2 3/4 plastic spinner and did a few flights no issues from screws

Today I will replace the self tapping screw system with bolts and locking nuts and try the three bladed again but goes to show that changing a few varibles can affect the vibration a lot

I suspect that the prop was too light and that makes high frequency vibration

I suspect that what i need is a three bladed 17*6 prop if such an animal exists

Balsaeater

Hobbsy

My Feedback: (102)

BE, the MA three bladers are factory balanced and need no further balancing unless you enlarged the hole and got it off center.

sodbuster 1

I know I've read it in the thread, but can't seem to find it.
What do you do to keep the exhaust system from loosening up ?
Am using a Saito 90deg elbow and the stock manifold/muffler that came with the engine.
It's a 100.
So far I've tried Blue Loctite and then Teflon tape but still the nuts loosen up.
I tighten it more than I'm comfortable with knowing the threads can pull out of the jug if I go too tight.

Do I need to use some type of bracket to attach the muffler to the motor mount maybe?
The engine is mounted inverted and the muffler exits from the bottom rear of the cowling pointing straight down.

weezle

I have a Saito 220 and I am 7000 RPM's on a 20x8 Xoar prop does sound right to you guys, or should I prop it down a little. I fly an extreme flight yak and I prefer to fly acrobatics. Any prop suggestions would be greatly appreciated.

Shubova

My Feedback: (9)

sodbuster1
You might want to try making a bracket that holds the muffler from turning, it doesn't have to be tight it just has to keep it form rotating. A tie wire rapped around the muffler and anchored at the ends to the plane with screws might work also.
I use blue Loctite on a Saito 125 that I have in a Seagull Extra 260 and it works fine. I have a Saito 180 in a GP Super Stearman and it comes loose even with the Loctite. Fortunately I had to cut a “U� shaped pocket in the bottom of the plane for the muffler and that keeps the muffler from rotating.
Another thing FYI if you read the instruction for that 90 degree elbow, they say not to use them with the stock muffler. Guaranteed it will brake, I used one and it broke just as they said. The 90 degree elbow is to be used with flex pipe they sell.
Good Luck and Happy Flying!
Shubova
[8D]

Capt Lou

Sod:

I read on this thread to use teflon tape. I also have uesed blue loctite. They both worked for me but every once in a while I must tighten the muffler.

sodbuster 1

I never saw any directions on the package. Of course I was just so happy the LHS actually had one in stock that I just ripped it out of the pkg and installed it.

Think I'm going to try the flex pipe and fasten it to the motor mount.
Should lose some of the weight working as a lever on that elbow.

balsaeater

Well in terms of balance it was nearly balanced
One blade was a tad heavy and a few scrapes from leading edge maybe a few grams of plactic and it seemed to balance
I did my best to make hole center with drilling out from 7 to 7.5 to 8 to 8.5... to 10mm
seemed good to me

When the engimne ran there was no sign of vibration but at full gas or near full gas the bolts screws stated to unwind and then vibration started big time and had to shut down pronto

Never seen that before

Balsaeater

blw

My Feedback: (3)

It sounds like you need a new prop. Out of balance 3 bladed props can do a lot of damage, even on much smaller engines than what you are running.

Shubova

My Feedback: (9)

sodbuster1

I didn't make it up about the elbow breaking. It says it right on the package and if you go on line they tell you there to. As I said mine broke first flight, but thats cool. Sounds like you found the right fix for your application.

I'm 60 years old and I always at least give the instuctions a glance, just to make sure. A 7 or 8 hundred dollar plane in the dirt is not fun day for me and I have lose ever plane that I have owned since I started this hobby but I can't stop I love it. As it's been said "Better save the sorry".
Good Luck,
Shubova
[8D]

Shubova

My Feedback: (9)

balsaeater
Are you using a reamer to enlarge the hole? You said “drilling� in your post. If not you should. A reamer is a lot more accurate.
I put a reamer in a drill press and run it as slow as possible. Make sure reamer is perpendicular to the hub and hold the prop tight. I also leveled my drill press and then leveled the table. I have heard that reaming on a drill press is not the right way to do it but it has been working for me. The hole will be perpendicluter to the hub, plus or minus the inaccuracy of the drill press. I think that's better then doing it by hand or with a hand held drill gun.
Hope this helps!
Good Luck,
Shubova
[8D]

balsaeater

I have done 5 props in APC 18* 6 w with hand drilling with the eye careful to verify each drilling went senter etc all replacements from prop strikes and all balanced and tracked with no issues

I think the three blade is as well done and the engine itself seems not to vibrate and tracking seemed correct

However next time I will do a three blade in a drill press

for now I will fix engine with locking nuts and run engine ground tests first to see if there is a imbalance
issue

if that shows issues i will try a salvage job with that prop
I will look for a 10mm inside diameter insert maybe 11mm outside diameter with 1mm thickness or 12 mm outside diameter with 2 mm thickness and drill out the prop in a on the press and reamer and see if that helps

Thanks for the info

Balsaeater

Shubova

My Feedback: (9)

balsaeater
I understand you may have other problems with the engine.
I would consider using a reamer too on your next prop. I have done a lot of machining and I was a Tooling Engineer for 30 years.
A drill bit is just not as accurate as a reamer that is ground to very close tolerances. But...As I always say it's your nickle.
When I build a plane I know that everthing is not going to be perfect. I just try to make everything as accurate as I can from the go. Even if it costs a little more money or time. So I after a few flights when something goes wrong I don't have to second guess everything. And I only use info from someone I really trust. Too many people just guess at things and before you know it you have paid for a new engine and or plane.
Again Good Luck and I hope it works out for you!
Shubova
[8D]

Shubova

My Feedback: (9)

FYI
Earlier in this thread I asked about the air intake thingy that sits on top of the carb. Someone said it is called trumpet and another said it is a stack, both are exceptable. I called and talked to a tech support at Horizon and he said it is called a "Volocity Stack". They run 6 to 10 bucks depending on the engine.
Thanks,
Shubova
[8D]

H5487

Hob,
I've already got a manual for one of the current-production 40a engines and will be using that as a starting point. Can you tell me off the top of your head if there's anything different that I need to do with my open-rockered 40? I already figured that I'll need to add a drop of after-run oil to the rocker bearings and cam follower openings before each flight.

Harvey

Hobbsy

My Feedback: (102)

Shub, I don't think you're going to hold a fourstroke with the sheet metal screws, I've held some pretty good sized Diesels with them but never took the chance on a fourstroke. The power pulses are too strong and spaced too far apart on a fourstroke.

Shubova

My Feedback: (9)

Hobbsy,
I'm really not sure what you are talking about. [sm=spinnyeyes.gif]What sheet metal screw? I never said anything about holding an engine with sheet metal screws.
In a pervious post I responded to someone that was having problems keeping the muffler from coming loose. He said he was thinking about making a bracket to hold the muffler from rotating. So I suggested taking a tie wire rap it loosely around the muffler then fastening it at the ends to the plane with screws. That would stop the muffler from pivoting and working itself off. Tie wire has enough give in it to take the vibration.
If that’s what you are talking about I’m sorry that your totally misconstrued my statement.
Thanks,
Shubova
[8D]

H5487

Hobbsy, is this what you were thinking of?

Harvey

ProBroJoe

Greetings all,

I'm fairly certain I want to get a Saito FA-40a to replace a Mag XL .30 RFS that's been giving me fits since day one. I know ya'll are die-hard Saito fans here and it's going to be hard to get an unbiased opinon, but is there anything bad to say about the FA-40a? I don't know why I didn't just get the Saito .40 in the first place as my 15 year old FA-50 is starts first flip nearly every time, idles at 2,000 RPM, and is still going strong (turns an APC 12 x 6 to 9,200).

Please forgive me for going astray and accept me into your club.

Oh, are there any reputable online retailers with a good price on the '40? I've looked and looked, and it seems like a fairly fixed-price market. []

-Joe

H5487

Joe, Welcome to the club!

I've bought some Saito engines from RC Superstore at a discount price and with good service. Try them at...

http://search.stores.ebay.com/RC-Sup...110024QQsofpZ0

Their website isn't currently showing an FA-40a but they'll be able to get it. The engines are new with the standard Saito three year warranty and the shipping is free! Plus they're cheaper than the usual retailers.

Harvey