fujiman

My Feedback: (133)

rule of thumb, if you run an 11'' 2 blade prop, go down in dia. to a 10'' 3 blade or go down in pitch 1 point. try both and see which performs the best. if you have a tachometer use that or just see how well your eng. is pulling in the vertical, and/or take off and climb out. with 3 blade you will lose a little efficiency compared to a 2 blade prop., hence the need to reduce prop dia. or pitch. HOPE this helped.



remember: fly in the middle of the air, danger lurks at the edges!!!!!!!!!!!!!

Hobbsy

My Feedback: (102)

Couger, a 12x6 three blade would be perfect, Master Airscrew makes one and a better looking one can be found here. The MA one is prebalanced.

www.zingerpropeller.com

http://www.zingerpropeller.com/3_bladed_Propeller.htm

hsukaria

I tried a 12x6x3 prop on the test stand and the engine revved about the same or better than a 13x6 on my Fox 74 Eagle IV. I plan on using that on the plane I will install it on for next season.

Cougar429

My Feedback: (3)

This is the smaller Eagle IV, (60). Will that prop selection still work? Asking as I have a 13/8 on my Saito 91 and that has considerably more torque.

earlwb

Yeah I think the 12x6 three blade would be fine on the Eagle IV .60 engine.

shark again

I saw a picture of a Fox 120 twin, like two 60's put together, in another thread (forgot just where). When did Fox do this - are there any available out there? It would be fun to mess around with that motor - something different for sure!
Jim S.

carddfann

There's one on ebay right now with 7 1/2 hours left of the auction. Its at $150 with 3 bids. They pop up on ebay or rcuniverse.com once in a while.

earlwb

That might have been my twin you saw. They show up on Ebay from time to time. The price runs around $200 to $350 US or thereabouts.
Yes it is made from two Fox Eagle III engines combined. Dual carbs and a alternate firing sequence. It tends to sound more like a old twin cylinder two stroke motorcycle engine.
Fox made them in in 1979 through the early 1980's. They are very powerful engines, you also run smaller props on them, as they like to rev up and not lug down with big props.
So a 13x6 up to maybe a 14x6 is the prop range.
For whatever reason, a lot of modellers have trouble adjusting Fox carbs. So if you have trouble adjusting a Fox carb, then having to deal with two Fox carbs might be an insurmountable obstruction.

shark again

Thanks for the picture, Earl. That is a neat motor! I have messed around with Fox motors for a while, have two planes flying with them now. Something Extra and Skyshark Fantasy with 45 and 46 (forget which has which).  I know the carbs are sort of a problem sometimes and I imagine having to get two of them working together would be tricky. That's what makes modeling fun.
I see Fox has a new carb again, I'm tempted to try one - $40 I think. The guys in the club say why do that, you can buy a whole new Chinese motor for that! I tell them I don't want a new Chinese motor!
Has anyone tried one of these new carbs?
Jim S.

landeck

My Feedback: (1)

I have one on a Fox 74 Eagle IV. I find it easy to set and is a good carb.

Bruce

hsukaria

A lot of the guys here have the new Two Needle (TN) carb. I swapped my old EZ carb for a new TN, even though I did not have much trouble with the old one. The transition seems smoother with the new TN, although the EZ had rapid transition. The truth is, I have not flown it yet with the new carb. But on the bench, it runs perfect.

Sport_Pilot

Looks like the special sale is to get rid of some 55 cc gas engines.

hsukaria

I didn't know Fox sold DLE engines!! I thought they serviced them only. What do I know??

earlwb

Yes the new Fox carb is a really nice carb. I have no qualms about swapping out old carbs for the new one. I have been doing it on some of my engines already.

KeroPower

I must say I was a little disappointed. I thought the sale was going to include their glow engines. I wonder if they sold all the DLE engines? I have no use for a 55cc engine. I do not need anymore engines right now anyway. I am very happy with my Fox .40 R/C sport I bought abouttwo years ago. Runs real nice. Carb needs little to noadjusting once set. It came with their new cube shaped carb.

KeroPower

I just wish they came with quieter mufflers that did not tilt up or down. Right now I have an O.S. FSR .40 muffler on my Fox.40. I had to elongate the holes a little bit and do some filing to get it to fit. It is pretty quiet now. I am using a Zinger 10x6 wood and no nitro home brew.

Cougar429

My Feedback: (3)

Kero, I totally agree about the noise level and a few of us have done the same. Due to the performance did not want to get rid of the motors just for that problem. My 50BB now has an OS muffler and just fit a Quiet Muffler on my Eagle IV. As for the 50 I would estimate the sound level dropped to half of before. I haven't run the Eagle yet as I just picked up a plane to put it in last weekend.

If you back up in this thread you can see mine and other muffler mods. Mine required adapters and I was able to fab them out of 7075 alloy, same material as propellors.

Sport_Pilot

IMO the Fox mufflers are not bad for an unbaffled single chamber design. I don't recall the FSR muffler as being that quiet either.

hsukaria

I ended up purchasing an MVVS 2-chamber muffler (Quiet) for my Eagle 74. Really makes it quiet with no performance drop compared to the Fox Tilt up/down. Besides, the plane I will put it on this winter cannot fit a tilt up/down muffler anyway (I have both). I don't know about the 40-50 sizes, but the MVVS muffler fit the Fox Eagle 74 without modifications or adapter.

Cougar429

My Feedback: (3)

Sport pilot, I modded my OS mufflers that came without them with baffles. Made a difference in sound levels and only a slight drop in performance.

fujiman

My Feedback: (133)

i'm experimenting with mufflers using aluminum window screen material and course steel wool much like the old auto hot rod glass pack mufflers. i haven't as yet been able to test performance perimeters and noise reduction as of yet, been doing a lot of hunting, etc. this year. i'll get back on track soon and will update, stay tuned!!!!!!!

hsukaria

I plan on experimenting with a mousse can muffler next. But I don't know how to do the stinger. Weld it? JB Liquid Weld? RTV? Also, what stinger diameter and length? Questions that I will have to get answers for before I proceed.

fujiman

My Feedback: (133)

i'd use maps gas and aluminum solder rod from welding supply. stringer of course would have to be aluminum also. polk some holes in a pop can and experiment with the alum. solder to get a feel for it. maps gas burns cleaner than propane gas and others. i was able to try this method out at a trade show and fell in love with it and have used this method since. hope this helps.

hsukaria

Thanks fujiman, I'll try that. Would you (or anybody else here) know where I can get the stinger tubing?

plaurence

My Feedback: (2)

What is a stinger and MAPS gas?