idvir

i want to get into 3D flying with my Funtana 40. I have an O.S 91 on it and currently flying with a 14*8 prop. what will be the best prop for 3D.

Thanks

drumbum

My Feedback: (1)

2 stroke or 4?

Fletch124

My Feedback: (7)

I'm running a 14x4w on my Saito72, but some guys with larger engines go 15x4w.

idvir

The engine is O.S 91. 4 stroke.

thanks

daveopam

My Feedback: (9)

APC 15x4W would be my first pick.


David

Razor-RCU

My Feedback: (50)

Yup, 15x4W

The 14x8 is a LOT of pitch for 3D and a pretty big load anyway...

ben beyer

My Feedback: (23)

I'm putting a Saito 91 on mine with a Pro Zinger 14x5.

etai4073

I don't know guys... The engine menual says that a recommended prop is 15X6 (if using diameter of 15...). I think with the 15X4W you might get too much RPM...

tIANci

15x6 is good for the plane, sometimes you want a little more pitch, you will see that if you get the combo right, its good to use 6" pitch over 4" W. I fly my F90 with a 16x6 and not the 16x4W, the 16x6 is much better.

daveopam

My Feedback: (9)

The 15x4W is about the same load on the engine as the 15x6. Unless your straight and level at WOT. The Wide blade really grabs a lot of air. Of course everyone has there own flying style along with 100 other variables.


David

WILDCRASHWILLY

I may be screwin-up but I put a 15X4W on a Saito 82 last week. I broke the engine in on a test stand and currently get 9000 RPM after going rich 300 RPM off of peak. This is after 3/4 of a gallon of YS 20/20 as that was the only four stroke fuel I had. I have not flown the Funtanna 40 yet. That will be next weekend I hope.

tIANci

Willy - get your Saito 82 to turn at about 10K, you will see how crisp the response will be. Go for the 14x4W.

Dyehard

My Saito 82 will turn 10500 with a 14x4W on 30% heli fuel. I tried a 15x4W on it and the verticle climb speed dropped by at least a third. All this while I had the 82 in my F40. I ended up cutting the 15x4W down to 14 inchs. I now have the 82 in a Harrier 46. Last weekend, while landing in a gusty crosswind, I managed to touch the prop tips. I cut the prop down to 13.25 inches, and, if anything, the verticle performance has inproved even more. The 15x4W is to much prop for the Saito 82, that is the prop that I would use on a Saito 100.

daveopam

My Feedback: (9)

I have to disagree. I run a .82 in a F-40. On 30% nitro it is perfect. I had a 14x4W on it during break in. I was only using 15% fuel and it was still trying to overspeed the engine. My experience seems the opposite of yours. The verticle with the 15" is a lot better than with the 14".



David

Dyehard

What do you consider overspeeding the 82? As I said, mine turns 10500 on the ground with the 14x4W. That means it is probably turning well over 11000 in the air, especially when the nose is down. My F 40 definitly climbed better with the 14 inch prop.

daveopam

My Feedback: (9)

Allen, I am under the impression that a engine gains 15% more rpm in the air. If this is true then 10,500 on the ground is 12,000 plus in the air. That is valve float territory on a Saito.
Mine was turning high 10's on the ground on 15% and this was only 5 tanks into the life of the engine. I did fly it that way. It was an improvement over the .72 that was in the nose. It was using a 14x4W on 30%. Once I went to the .82 on 30% with the 15x4W there was no going back.
At my field at my ALT. the 15x4w just flat out climbs the 14x4w. It really isn't close. When I put a demo on at a fly-in most guys think I am running a 1.00.

There is one other difference between our set ups. I am using the old style straight through muffler. My cowl was already cut for it from the .72.I guess these mufflers could be showing some difference?

David

WILDCRASHWILLY

Thanks Guys, I'll experiment with the props a little. I had purchased a couple of 15X4ws and at 9000 thought it might unload another 500 rpm or so when in flight. Althoug I have not flown the plane yet, it does seem to pull really hard. I read a review somewhere, "don't remember where", that the 82a should not turn over 10,000 but I may be mistaken as their manual shows some rpm levels higher than 10k. The 82a is my first four stroke, until now I've run 2 strokes in the 25, 40, 46 and 52 ranges. Although the rpms are lower than what I'm used to, it seems to have much more power when I run it. I,m baseing this strictly on how it feels when I hold the plane by hand. I hope to fly this next week depending on work and weather.

Dyehard

David, you are right, there are too many variables here. I fly at between 2000 and 2500 feet above sea level. That's the ground level around here. That and the muffler might be effecting how the engine produces power and how the prop bites. I just know that after flying for almost a year and having the F40 almost jump out of a hover and climb like a scalded cat with a 14x4W, I tried a 15x4W and it was very sluggish coming out of a hover and climbing. I flew it about three tanks with the 15 inch prop and changed back to the forteen inch prop, the performance immediatly came back. Took the 15 inch home and cut it down to 14 inches, it's in my field box now as a spare. The 14x4W is the prop that Horizon recommended for the 72 and I also figured that the 82 would spin a bigger prop. It took a year before the local hobby shop got around to getting in a 15x4W, I tried one and it didn't work out for my. I was at the XFC last year and someone was flying a Funtana 40 there after the contest was over for the evening. I mentioned to him that I was going to put a 15x4W on mine and he said it wouldn't turn it well and I would end up going with the 14x4W, so apparently others had the same results as me. As for the airborne RPM, there is no way I can tell certain what it is, I just know that I have been flying the 82 for over a year with this setup and it has never complained. The valves have only been adjusted twice, once right after breakin and then last week. They were barely out, I probably could have kept flying the way they were. I don't think the wide blade props unload like the narrow props, it certainly doesn't sound like it is going over 12000. If it is, it is handleing it well.
Bill, the manual shows the 82 turning up to 12500 RPM. The power lives in the upper part of the band. If you expect the most performance out your engine, you will have to spin it faster than 9000 RPM. BTW, what fuel are you using. I'm curious, because if you are using 30% and only getting 9000 with the 15x4W, then you are getting the same results I did with that prop.

WILDCRASHWILLY

Allen, I used ys 20/20. I have run just over 1/2 gallon of fuel on the test stand. The engine peaked at 9300 at this time and I backed off 300rpm to the rich getting 9000. It may turn higher as I run a gallon or two of fuel through it. I have three of the 15X4Ws, looks like I need to get some 14X4Ws as well to try. Everyone ran the 14s on the 72 so I bought the 15s for the 82.

AGR413

My Feedback: (1)

Hi guys, glad I found this,
I am running the 14x4w on the .82 and have been considering trying the 15x4w, don't know if I will now. I can't really justify changing anything I am at 4000 ft and have a lot of excess power on this setup. No problem hovering, pulling out etc etc. My engine is just now finishing break in after 2 gallons, one on the ground and one in the air, I knew it is finishing breaking in because I had to adjust the idle mixture. I am running at 10K rpm, it peaks at 10,500 on the ground but I set it at 10,000 for safety sake, on 15% cool power. The manual says the high end on this engine is 12,000.

The fist thing I was going to try is using 20/20 to see if I can speed up the response a little, it's not bad now but could be better. Do you think the 20/20 will help with this? I obviously don't need more rpm's.

I have heard many folks use the 15x4w on this setup to decrease the torque rolling on this airplane. I have not tried it so I don't know.

WILDCRASHWILLY

Also, I would like to add that I'm only at about 300 to 350 feet in altitude at this location so we don't require overkill on power to get off the ground.

daveopam

My Feedback: (9)

I think the YS 20/20 is a good choice for this engine. I run the Riches Brew 30% airplane blend. It has a little castor.(don't want to start a castor debate) I should also mention I don't see a big difference in RPM going from 15% to 30%. The difference is in the spool up. I tried a 14x4W and a Zinger Pro 14x4 on my .72. The difference in throttle response between those two props. Is the difference between 15% & 30%. It is really dramatic. More so when the plane is verticle.


David

Razor-RCU

My Feedback: (50)

I was thinking you were runnin' a 91 2 cy. for some reason...

I defer to the 4 cycle experts above but my ST G-90 (2 cycle) likes a 15x4 Pro-Zinger... I get about 10K and a lot of torque!

Cheers!

AGR413

My Feedback: (1)

So which one do you feel is better the wide blade or the zinger?

mwarren400

Am also flying a Funtana .40 ...but with an Evolution .61 in it. Does anyone have any exerience with this combo. Am running a 12x7 right now with 15%. Newbie here ...so i'd appreciate any input. Elevation is approx 1500ft.