seagull2200

Hi

I've just got my first 4 stroke engine - a Saito FA-40 Special - it's in good condition with strong compression but i think is an old engine.

Anyhow, it's going onto a 1909 Bleriot replica, but when I came to buy the wooden prop from my model shop they tried to guide me away from buying a wooden prop!

They say that there's not enough weight in a wooden prop to produce the 'fly-wheel' effect required for a 4stroke, and the engine would apparently be back-firing.[]

A plastic prop would look silly on this model - any suggestions - and if ok for the wooden prop - what size would i need - it's a lightweight model which i wish to fly SLOWLY for Sundays afternoons.

Also, In line with the scale aspect - I won't be looking to put a spinner on it - as the original Bleriot didn't - but what could i use to get a 'bite' for the electric starter - or am i going to have to get used to spending hours on my knees trying to persuade the engine to start by hand?

Thanks in advance

FlyerBry

My Feedback: (8)

I have run a wooden prop on my O.S. .70 four stroke mounted in my Cub without any problems at all. Maybe this is a problem on smaller four strokes? Wooden props in the smaller sizes are cheap, why not buy one and try it. If it runs OK at idle on the ground I would think it would be fine in the air where the airspeed of the plane should aid in keeping the prop turning.

abufletcher

Nonsense! A wooden prop will be just fine. You should be able to use your electric starter just by reversing the standard plastic/rubber tip.

Edwin

My Feedback: (2)

Agreed. Nonsense. I run them on saito 120s and 180s.
Edwin

TLH101

My Feedback: (90)

Looks like you need to shop around for a hobby shop with experienced personel behind the counter. People with your interest in mind instead of theirs.
Wood props work just fine on 4 strokes.

dicknadine

What kind of a Model shop are you visting? have been flying wood 2 and 3 props on 4 strokes for years, and many other builders, flyers at our field the same without any problems. suggest you find another local expert hobby shop. dick

carlosponti

My Feedback: (1)

i had been told this as well! though i have seen bigger 4 strokes with wooden props. couldnt hurt to put on on a test stand and run it. wooden prop not having a flywheel effect would just mean it would backfire and die according to everything i was told.

grbaker

My Feedback: (29)

I used to have an OS .48 Surpass 4 stroke and ran only wood props on it with no problems.

fireplug1111

My Feedback: (21)

Unless your engine has a brain it wont know the difference. It wont know if its a wood prop, plastic prop, carbon fiber prop. or even a piece of plywood, if it spins and its balanced the engine is happy. Id go back to your LHS and take a look at thier application for employment and see if any education is required?
Most likely not.

Alan

GAP-RCU

My Saito 30 runs great with a wood prop, usually a Zinger 11x4. I've run it with and without a spinner, the engine doesn't care. I forget what it tachs at for idle, but with the large diameter and flat pitch, my Sig LT-25 slows down to a crawl for landing.

If your starter can accept a Sullivan brand cone, they make one for bare props. It's number S635; you can find it on their website.

http://www.sullivanproducts.com/index.htm

Finally, the main reason for 4 stroke backfires is too lean a needle setting. With four strokes, many folks have a harder time setting the engine by ear, myself included, so my tach is always in the flight box.

Gary

abufletcher

I bought one of these but consider them extremely hazardous! Almost every time I've used it it gets torn out and launched into the pits by the propeller outspinning it once the engine catches. You have to be prepared to pull the starting away from the prop the moment the engine starts. You can't keep it on like you would with a spinner.

A much better option (that costs nothing) is just to reverse the standard rubber insert. The hole will slip nicely over the nut yet still allow some slippage after the engine starts.

Edwin

My Feedback: (2)

I have found that the back firing is more a function of a carb tune. Sure I've have back fires with wooden props, AND composite. But a little tweeking on the carb and all is fine.
Edwin

TexasAirBoss

My Feedback: (22)

Hobby shop employees are always trying to sell you what they have rather than what you need.

And they generally have very very limited experience. I disregard everything they say after, " no we don't have that, but we can order it."

SoCalSal

My Feedback: (16)

I use a 32x12 wood prop on my RCS 215 Radial. Don't see why you can't use smaller ones on smaller engines. Horse feathers. You can use wood props on your engine.

CafeenMan

I never heard that a wood prop can't be used on a 4-stroke. I have limited experience with 4-strokes, but I use wood props almost exclusively on all my engines. No problems noted.

fredscz

My Feedback: (47)

Check and see if Master Air Screw makes a wooden scimitar prop in the size you need. They look neat on the vintage planes and they are very efficient.
I have tried the sullivan insert for the bare props and it does exactly as the previous poster said.
FEB

glowplug50

Ok all you experts, wood props do work just fine on 4 cycle engines. They do however have a problem that synthetic props do not. They compress when tightening the prop nut and and therefore can loose the tension netween the thrust washer and the prop nut. If a back fire occurs, and frequently does during the starting process or even in the air, throwing the prop is a higher risk with a wooden prop. Don't forget to use those locknuts that come with the engine.

CafeenMan

GlowPlug - you're absolutely correct, but the problem exists with wood props on any engine. But after a while they compress as much as they're going to. You should still check ANY prop as part of your pre-flight but after you've tightened a wood prop a half dozen times you should find that it isn't coming loose any more.

Propellers are dangerous and too many people just don't take them seriously enough as evidenced by behavior I've witnessed at the field and people in the hobby missing body parts due to propellers.

SoCalSal

My Feedback: (16)

I agree with this statment. I have used nothing but wood props on my RCS 215. There is a compressing of the wood the first couple of times untill it "sets" then all is well. You should ALWAYS check your prop nut (nuts) before every flight. This is just one step in basic pre-flighting any aircrafte of any size. My 215 will at times try to kick back as I turn it to get it primed and positioned for fliping and never have I had a bolt come loose. And belive me when this engine kicks back it is with a lot of force. I have to hand start it and learned very quickley that a good thick glove is a must, belive me, it kicked back one time and slapped the back side of my hand. I thought it broke my fingers but all I got was a bad bruise and a quick lesson on wearing a starting glove. Also wear some type of eye protection ALWAYS as the prop can kick up FOD from the ground into your eyes, I learned this the hard way as well. SAFETY FIRST ALWAYS

carlbecker

My Feedback: (3)

Wood props will compress. Use both nuts and make sure they are tight. Spend as little time as possible in front of the prop and don't let others watch while standing in the front 180 degrees of the spinning prop. Have them stay behind is the best rule IMHO. The engine will respond differently with props of different weight. The engine doesn't have a brain but the weight of the prop changes the flywheel effect. Wood props are more fragile, I can break them easily. APC props are heavy and tough. Carbon are light and tough. Tune your motor right and you will probably never have a backfire, which im my opinion is caused by a lean mixture. I use props to help balance the CG as the weight is right up front. I don't use wood because I'm to hard on them. I don't 3D or pattern so I'm not to concerned about instant throttle response either, lighter prop quicker rpm pickup.

Carl

khodges

My Feedback: (1)

If you're not running lean, you should have very little problems with backfires, in the air or on the ground, and the little locknut, IMO, is useless in preventing the nut from being spit off. I saw a .70 Surpass spit both the nut and locknut 30 feet after a backfire during starting. The prop looked like an APC Frisbee[X(].

I make sure my wood prop is a snug (read:tight as heck) fit on the shaft to start with, and then tighten the prop nut until it compresses the washer about a millimeter into the wood. Never had one kick off, all I fly is 4-strokes. The one thing I notice with wood props is that you get very little windmilling when you kill the engine, it just stops, because of less weight, there's less inertia. I read all the time about the heavier nylon props allowing lower idles, and maybe they do, but my wood propped Saitos idle as low as my nylon propped ones do.

The only thing I DON'T like about wood is they're more likely to break if you ground loop or strike the tips; I have a gasser that used to be bad to nose over on landing (until I modified the main gear). Cost me over a $100 in props (20-6) in less than a month.

jaka

Hi!
Totally nonsens!
I used wooden props on all my fourstrokes for decades. Of course you have to retighten a wodden prop! Nothing strange about that...I personaly never use a lock nut on any of my fourstrokes and have never had one trown a prop.

vertical grimmace

My Feedback: (1)

Unfortunately these types of comments from LHS is the reason why they are becoming extinct. When they make the comment " no, but I can order it for you" I just say," I can order it for myself"! The worst is wheen mis-information is given to beginners. I saw a guy talked into buying a super Chipmunk that had never flown before! That plane certainly had a short life along with this gentlemans flying carrer.

glowplug50

Well Jaka, I don't use them either, but I did meet a fellow with a large scar across his neck who did have one pop off on him. Time will tell for you Mr no nonsense and passing on its never happened to me info like yours is irresposible. As far as engines set to lean, yes that is a culprit, but even a properly adjusted carb if choked to much or to little can cause a backfire.

Jimmy Bananas

My Feedback: (13)

I perfer wooden props when ever possible....after my little run in with a wooden prop, last summer, if that would of been a fiberglass prop, I would of lost a finger...total stiches was 35..got caught on a wooden zinger 14-6 prop....S&$% happens......I think I'll stick with the wooden ones.........